| Age | Commit message (Collapse) | Author | Files | Lines |
|---|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull mm updates from Andrew Morton:
"The usual shower of singleton fixes and minor series all over MM,
documented (hopefully adequately) in the respective changelogs.
Notable series include:
- Lucas Stach has provided some page-mapping cleanup/consolidation/
maintainability work in the series "mm/treewide: Remove pXd_huge()
API".
- In the series "Allow migrate on protnone reference with
MPOL_PREFERRED_MANY policy", Donet Tom has optimized mempolicy's
MPOL_PREFERRED_MANY mode, yielding almost doubled performance in
one test.
- In their series "Memory allocation profiling" Kent Overstreet and
Suren Baghdasaryan have contributed a means of determining (via
/proc/allocinfo) whereabouts in the kernel memory is being
allocated: number of calls and amount of memory.
- Matthew Wilcox has provided the series "Various significant MM
patches" which does a number of rather unrelated things, but in
largely similar code sites.
- In his series "mm: page_alloc: freelist migratetype hygiene"
Johannes Weiner has fixed the page allocator's handling of
migratetype requests, with resulting improvements in compaction
efficiency.
- In the series "make the hugetlb migration strategy consistent"
Baolin Wang has fixed a hugetlb migration issue, which should
improve hugetlb allocation reliability.
- Liu Shixin has hit an I/O meltdown caused by readahead in a
memory-tight memcg. Addressed in the series "Fix I/O high when
memory almost met memcg limit".
- In the series "mm/filemap: optimize folio adding and splitting"
Kairui Song has optimized pagecache insertion, yielding ~10%
performance improvement in one test.
- Baoquan He has cleaned up and consolidated the early zone
initialization code in the series "mm/mm_init.c: refactor
free_area_init_core()".
- Baoquan has also redone some MM initializatio code in the series
"mm/init: minor clean up and improvement".
- MM helper cleanups from Christoph Hellwig in his series "remove
follow_pfn".
- More cleanups from Matthew Wilcox in the series "Various
page->flags cleanups".
- Vlastimil Babka has contributed maintainability improvements in the
series "memcg_kmem hooks refactoring".
- More folio conversions and cleanups in Matthew Wilcox's series:
"Convert huge_zero_page to huge_zero_folio"
"khugepaged folio conversions"
"Remove page_idle and page_young wrappers"
"Use folio APIs in procfs"
"Clean up __folio_put()"
"Some cleanups for memory-failure"
"Remove page_mapping()"
"More folio compat code removal"
- David Hildenbrand chipped in with "fs/proc/task_mmu: convert
hugetlb functions to work on folis".
- Code consolidation and cleanup work related to GUP's handling of
hugetlbs in Peter Xu's series "mm/gup: Unify hugetlb, part 2".
- Rick Edgecombe has developed some fixes to stack guard gaps in the
series "Cover a guard gap corner case".
- Jinjiang Tu has fixed KSM's behaviour after a fork+exec in the
series "mm/ksm: fix ksm exec support for prctl".
- Baolin Wang has implemented NUMA balancing for multi-size THPs.
This is a simple first-cut implementation for now. The series is
"support multi-size THP numa balancing".
- Cleanups to vma handling helper functions from Matthew Wilcox in
the series "Unify vma_address and vma_pgoff_address".
- Some selftests maintenance work from Dev Jain in the series
"selftests/mm: mremap_test: Optimizations and style fixes".
- Improvements to the swapping of multi-size THPs from Ryan Roberts
in the series "Swap-out mTHP without splitting".
- Kefeng Wang has significantly optimized the handling of arm64's
permission page faults in the series
"arch/mm/fault: accelerate pagefault when badaccess"
"mm: remove arch's private VM_FAULT_BADMAP/BADACCESS"
- GUP cleanups from David Hildenbrand in "mm/gup: consistently call
it GUP-fast".
- hugetlb fault code cleanups from Vishal Moola in "Hugetlb fault
path to use struct vm_fault".
- selftests build fixes from John Hubbard in the series "Fix
selftests/mm build without requiring "make headers"".
- Memory tiering fixes/improvements from Ho-Ren (Jack) Chuang in the
series "Improved Memory Tier Creation for CPUless NUMA Nodes".
Fixes the initialization code so that migration between different
memory types works as intended.
- David Hildenbrand has improved follow_pte() and fixed an errant
driver in the series "mm: follow_pte() improvements and acrn
follow_pte() fixes".
- David also did some cleanup work on large folio mapcounts in his
series "mm: mapcount for large folios + page_mapcount() cleanups".
- Folio conversions in KSM in Alex Shi's series "transfer page to
folio in KSM".
- Barry Song has added some sysfs stats for monitoring multi-size
THP's in the series "mm: add per-order mTHP alloc and swpout
counters".
- Some zswap cleanups from Yosry Ahmed in the series "zswap
same-filled and limit checking cleanups".
- Matthew Wilcox has been looking at buffer_head code and found the
documentation to be lacking. The series is "Improve buffer head
documentation".
- Multi-size THPs get more work, this time from Lance Yang. His
series "mm/madvise: enhance lazyfreeing with mTHP in madvise_free"
optimizes the freeing of these things.
- Kemeng Shi has added more userspace-visible writeback
instrumentation in the series "Improve visibility of writeback".
- Kemeng Shi then sent some maintenance work on top in the series
"Fix and cleanups to page-writeback".
- Matthew Wilcox reduces mmap_lock traffic in the anon vma code in
the series "Improve anon_vma scalability for anon VMAs". Intel's
test bot reported an improbable 3x improvement in one test.
- SeongJae Park adds some DAMON feature work in the series
"mm/damon: add a DAMOS filter type for page granularity access recheck"
"selftests/damon: add DAMOS quota goal test"
- Also some maintenance work in the series
"mm/damon/paddr: simplify page level access re-check for pageout"
"mm/damon: misc fixes and improvements"
- David Hildenbrand has disabled some known-to-fail selftests ni the
series "selftests: mm: cow: flag vmsplice() hugetlb tests as
XFAIL".
- memcg metadata storage optimizations from Shakeel Butt in "memcg:
reduce memory consumption by memcg stats".
- DAX fixes and maintenance work from Vishal Verma in the series
"dax/bus.c: Fixups for dax-bus locking""
* tag 'mm-stable-2024-05-17-19-19' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (426 commits)
memcg, oom: cleanup unused memcg_oom_gfp_mask and memcg_oom_order
selftests/mm: hugetlb_madv_vs_map: avoid test skipping by querying hugepage size at runtime
mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_wp
mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_fault
selftests: cgroup: add tests to verify the zswap writeback path
mm: memcg: make alloc_mem_cgroup_per_node_info() return bool
mm/damon/core: fix return value from damos_wmark_metric_value
mm: do not update memcg stats for NR_{FILE/SHMEM}_PMDMAPPED
selftests: cgroup: remove redundant enabling of memory controller
Docs/mm/damon/maintainer-profile: allow posting patches based on damon/next tree
Docs/mm/damon/maintainer-profile: change the maintainer's timezone from PST to PT
Docs/mm/damon/design: use a list for supported filters
Docs/admin-guide/mm/damon/usage: fix wrong schemes effective quota update command
Docs/admin-guide/mm/damon/usage: fix wrong example of DAMOS filter matching sysfs file
selftests/damon: classify tests for functionalities and regressions
selftests/damon/_damon_sysfs: use 'is' instead of '==' for 'None'
selftests/damon/_damon_sysfs: find sysfs mount point from /proc/mounts
selftests/damon/_damon_sysfs: check errors from nr_schemes file reads
mm/damon/core: initialize ->esz_bp from damos_quota_init_priv()
selftests/damon: add a test for DAMOS quota goal
...
|
|
Patch series "mm/ksm: fix ksm exec support for prctl", v4.
commit 3c6f33b7273a ("mm/ksm: support fork/exec for prctl") inherits
MMF_VM_MERGE_ANY flag when a task calls execve(). However, it doesn't
create the mm_slot, so ksmd will not try to scan this task. The first
patch fixes the issue.
The second patch refactors to prepare for the third patch. The third
patch extends the selftests of ksm to verfity the deduplication really
happens after fork/exec inherits ths KSM setting.
This patch (of 3):
commit 3c6f33b7273a ("mm/ksm: support fork/exec for prctl") inherits
MMF_VM_MERGE_ANY flag when a task calls execve(). Howerver, it doesn't
create the mm_slot, so ksmd will not try to scan this task.
To fix it, allocate and add the mm_slot to ksm_mm_head in __bprm_mm_init()
when the mm has MMF_VM_MERGE_ANY flag.
Link: https://lkml.kernel.org/r/20240328111010.1502191-1-tujinjiang@huawei.com
Link: https://lkml.kernel.org/r/20240328111010.1502191-2-tujinjiang@huawei.com
Fixes: 3c6f33b7273a ("mm/ksm: support fork/exec for prctl")
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Stefan Roesch <shr@devkernel.io>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Add "sched_prepare_exec" tracepoint, which is run right after the point
of no return but before the current task assumes its new exec identity.
Unlike the tracepoint "sched_process_exec", the "sched_prepare_exec"
tracepoint runs before flushing the old exec, i.e. while the task still
has the original state (such as original MM), but when the new exec
either succeeds or crashes (but never returns to the original exec).
Being able to trace this event can be helpful in a number of use cases:
* allowing tracing eBPF programs access to the original MM on exec,
before current->mm is replaced;
* counting exec in the original task (via perf event);
* profiling flush time ("sched_prepare_exec" to "sched_process_exec").
Example of tracing output:
$ cat /sys/kernel/debug/tracing/trace_pipe
<...>-379 [003] ..... 179.626921: sched_prepare_exec: interp=/usr/bin/sshd filename=/usr/bin/sshd pid=379 comm=sshd
<...>-381 [002] ..... 180.048580: sched_prepare_exec: interp=/bin/bash filename=/bin/bash pid=381 comm=sshd
<...>-385 [001] ..... 180.068277: sched_prepare_exec: interp=/usr/bin/tty filename=/usr/bin/tty pid=385 comm=bash
<...>-389 [006] ..... 192.020147: sched_prepare_exec: interp=/usr/bin/dmesg filename=/usr/bin/dmesg pid=389 comm=bash
Signed-off-by: Marco Elver <elver@google.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20240411102158.1272267-1-elver@google.com
Signed-off-by: Kees Cook <keescook@chromium.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull execve fixes from Kees Cook:
- Fix selftests to conform to the TAP output format (Muhammad Usama
Anjum)
- Fix NOMMU linux_binprm::exec pointer in auxv (Max Filippov)
- Replace deprecated strncpy usage (Justin Stitt)
- Replace another /bin/sh instance in selftests
* tag 'execve-v6.9-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
binfmt: replace deprecated strncpy
exec: Fix NOMMU linux_binprm::exec in transfer_args_to_stack()
selftests/exec: Convert remaining /bin/sh to /bin/bash
selftests/exec: execveat: Improve debug reporting
selftests/exec: recursion-depth: conform test to TAP format output
selftests/exec: load_address: conform test to TAP format output
selftests/exec: binfmt_script: Add the overall result line according to TAP
|
|
In NOMMU kernel the value of linux_binprm::p is the offset inside the
temporary program arguments array maintained in separate pages in the
linux_binprm::page. linux_binprm::exec being a copy of linux_binprm::p
thus must be adjusted when that array is copied to the user stack.
Without that adjustment the value passed by the NOMMU kernel to the ELF
program in the AT_EXECFN entry of the aux array doesn't make any sense
and it may break programs that try to access memory pointed to by that
entry.
Adjust linux_binprm::exec before the successful return from the
transfer_args_to_stack().
Cc: <stable@vger.kernel.org>
Fixes: b6a2fea39318 ("mm: variable length argument support")
Fixes: 5edc2a5123a7 ("binfmt_elf_fdpic: wire up AT_EXECFD, AT_EXECFN, AT_SECURE")
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Link: https://lore.kernel.org/r/20240320182607.1472887-1-jcmvbkbc@gmail.com
Signed-off-by: Kees Cook <keescook@chromium.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull execve updates from Kees Cook:
- Drop needless error path code in remove_arg_zero() (Li kunyu, Kees
Cook)
- binfmt_elf_efpic: Don't use missing interpreter's properties (Max
Filippov)
- Use /bin/bash for execveat selftests
* tag 'execve-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
exec: Simplify remove_arg_zero() error path
selftests/exec: Perform script checks with /bin/bash
exec: Delete unnecessary statements in remove_arg_zero()
fs: binfmt_elf_efpic: don't use missing interpreter's properties
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull pdfd updates from Christian Brauner:
- Until now pidfds could only be created for thread-group leaders but
not for threads. There was no technical reason for this. We simply
had no users that needed support for this. Now we do have users that
need support for this.
This introduces a new PIDFD_THREAD flag for pidfd_open(). If that
flag is set pidfd_open() creates a pidfd that refers to a specific
thread.
In addition, we now allow clone() and clone3() to be called with
CLONE_PIDFD | CLONE_THREAD which wasn't possible before.
A pidfd that refers to an individual thread differs from a pidfd that
refers to a thread-group leader:
(1) Pidfds are pollable. A task may poll a pidfd and get notified
when the task has exited.
For thread-group leader pidfds the polling task is woken if the
thread-group is empty. In other words, if the thread-group
leader task exits when there are still threads alive in its
thread-group the polling task will not be woken when the
thread-group leader exits but rather when the last thread in the
thread-group exits.
For thread-specific pidfds the polling task is woken if the
thread exits.
(2) Passing a thread-group leader pidfd to pidfd_send_signal() will
generate thread-group directed signals like kill(2) does.
Passing a thread-specific pidfd to pidfd_send_signal() will
generate thread-specific signals like tgkill(2) does.
The default scope of the signal is thus determined by the type
of the pidfd.
Since use-cases exist where the default scope of the provided
pidfd needs to be overriden the following flags are added to
pidfd_send_signal():
- PIDFD_SIGNAL_THREAD
Send a thread-specific signal.
- PIDFD_SIGNAL_THREAD_GROUP
Send a thread-group directed signal.
- PIDFD_SIGNAL_PROCESS_GROUP
Send a process-group directed signal.
The scope change will only work if the struct pid is actually
used for this scope.
For example, in order to send a thread-group directed signal the
provided pidfd must be used as a thread-group leader and
similarly for PIDFD_SIGNAL_PROCESS_GROUP the struct pid must be
used as a process group leader.
- Move pidfds from the anonymous inode infrastructure to a tiny pseudo
filesystem. This will unblock further work that we weren't able to do
simply because of the very justified limitations of anonymous inodes.
Moving pidfds to a tiny pseudo filesystem allows for statx on pidfds
to become useful for the first time. They can now be compared by
inode number which are unique for the system lifetime.
Instead of stashing struct pid in file->private_data we can now stash
it in inode->i_private. This makes it possible to introduce concepts
that operate on a process once all file descriptors have been closed.
A concrete example is kill-on-last-close. Another side-effect is that
file->private_data is now freed up for per-file options for pidfds.
Now, each struct pid will refer to a different inode but the same
struct pid will refer to the same inode if it's opened multiple
times. In contrast to now where each struct pid refers to the same
inode.
The tiny pseudo filesystem is not visible anywhere in userspace
exactly like e.g., pipefs and sockfs. There's no lookup, there's no
complex inode operations, nothing. Dentries and inodes are always
deleted when the last pidfd is closed.
We allocate a new inode and dentry for each struct pid and we reuse
that inode and dentry for all pidfds that refer to the same struct
pid. The code is entirely optional and fairly small. If it's not
selected we fallback to anonymous inodes. Heavily inspired by nsfs.
The dentry and inode allocation mechanism is moved into generic
infrastructure that is now shared between nsfs and pidfs. The
path_from_stashed() helper must be provided with a stashing location,
an inode number, a mount, and the private data that is supposed to be
used and it will provide a path that can be passed to dentry_open().
The helper will try retrieve an existing dentry from the provided
stashing location. If a valid dentry is found it is reused. If not a
new one is allocated and we try to stash it in the provided location.
If this fails we retry until we either find an existing dentry or the
newly allocated dentry could be stashed. Subsequent openers of the
same namespace or task are then able to reuse it.
- Currently it is only possible to get notified when a task has exited,
i.e., become a zombie and userspace gets notified with EPOLLIN. We
now also support waiting until the task has been reaped, notifying
userspace with EPOLLHUP.
- Ensure that ESRCH is reported for getfd if a task is exiting instead
of the confusing EBADF.
- Various smaller cleanups to pidfd functions.
* tag 'vfs-6.9.pidfd' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (23 commits)
libfs: improve path_from_stashed()
libfs: add stashed_dentry_prune()
libfs: improve path_from_stashed() helper
pidfs: convert to path_from_stashed() helper
nsfs: convert to path_from_stashed() helper
libfs: add path_from_stashed()
pidfd: add pidfs
pidfd: move struct pidfd_fops
pidfd: allow to override signal scope in pidfd_send_signal()
pidfd: change pidfd_send_signal() to respect PIDFD_THREAD
signal: fill in si_code in prepare_kill_siginfo()
selftests: add ESRCH tests for pidfd_getfd()
pidfd: getfd should always report ESRCH if a task is exiting
pidfd: clone: allow CLONE_THREAD | CLONE_PIDFD together
pidfd: exit: kill the no longer used thread_group_exited()
pidfd: change do_notify_pidfd() to use __wake_up(poll_to_key(EPOLLIN))
pid: kill the obsolete PIDTYPE_PID code in transfer_pid()
pidfd: kill the no longer needed do_notify_pidfd() in de_thread()
pidfd_poll: report POLLHUP when pid_task() == NULL
pidfd: implement PIDFD_THREAD flag for pidfd_open()
...
|
|
We don't need the "out" label any more, so remove "ret" and return
directly on error.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: linux-mm@kvack.org
Cc: linux-fsdevel@vger.kernel.org
|
|
'ret=0; ' In actual operation, the ret was not modified, so this
sentence can be removed.
Signed-off-by: Li kunyu <kunyu@nfschina.com>
Link: https://lore.kernel.org/r/20240220052426.62018-1-kunyu@nfschina.com
Signed-off-by: Kees Cook <keescook@chromium.org>
|
|
Now that __change_pid() does wake_up_all(&pid->wait_pidfd) we can kill
do_notify_pidfd(leader) in de_thread(), it calls release_task(leader)
right after that and this implies detach_pid(leader, PIDTYPE_PID).
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20240202131248.GA26022@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
With this flag:
- pidfd_open() doesn't require that the target task must be
a thread-group leader
- pidfd_poll() succeeds when the task exits and becomes a
zombie (iow, passes exit_notify()), even if it is a leader
and thread-group is not empty.
This means that the behaviour of pidfd_poll(PIDFD_THREAD,
pid-of-group-leader) is not well defined if it races with
exec() from its sub-thread; pidfd_poll() can succeed or not
depending on whether pidfd_task_exited() is called before
or after exchange_tids().
Perhaps we can improve this behaviour later, pidfd_poll()
can probably take sig->group_exec_task into account. But
this doesn't really differ from the case when the leader
exits before other threads (so pidfd_poll() succeeds) and
then another thread execs and pidfd_poll() will block again.
thread_group_exited() is no longer used, perhaps it can die.
Co-developed-by: Tycho Andersen <tycho@tycho.pizza>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20240131132602.GA23641@redhat.com
Tested-by: Tycho Andersen <tandersen@netflix.com>
Reviewed-by: Tycho Andersen <tandersen@netflix.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull execve fixes from Kees Cook:
- Fix error handling in begin_new_exec() (Bernd Edlinger)
- MAINTAINERS: specifically mention ELF (Alexey Dobriyan)
- Various cleanups related to earlier open() (Askar Safin, Kees Cook)
* tag 'execve-v6.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
exec: Distinguish in_execve from in_exec
exec: Fix error handling in begin_new_exec()
exec: Add do_close_execat() helper
exec: remove useless comment
ELF, MAINTAINERS: specifically mention ELF
|
|
Jann Horn points out that uselib() really shouldn't trigger the new
FMODE_EXEC logic introduced by commit 4759ff71f23e ("exec: __FMODE_EXEC
instead of in_execve for LSMs").
In fact, it shouldn't even have ever triggered the old pre-existing
logic for __FMODE_EXEC (like the NFS code that makes executables not
need read permissions). Unlike a real execve(), that can work even with
files that are purely executable by the user (not readable), uselib()
has that MAY_READ requirement becasue it's really just a convenience
wrapper around mmap() for legacy shared libraries.
The whole FMODE_EXEC bit was originally introduced by commit
b500531e6f5f ("[PATCH] Introduce FMODE_EXEC file flag"), primarily to
give ETXTBUSY error returns for distributed filesystems.
It has since grown a few other warts (like that NFS thing), but there
really isn't any reason to use it for uselib(), and now that we are
trying to use it to replace the horrid 'tsk->in_execve' flag, it's
actively wrong.
Of course, as Jann Horn also points out, nobody should be enabling
CONFIG_USELIB in the first place in this day and age, but that's a
different discussion entirely.
Reported-by: Jann Horn <jannh@google.com>
Fixes: 4759ff71f23e ("exec: __FMODE_EXEC instead of in_execve for LSMs")
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Just to help distinguish the fs->in_exec flag from the current->in_execve
flag, add comments in check_unsafe_exec() and copy_fs() for more
context. Also note that in_execve is only used by TOMOYO now.
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-mm@kvack.org
Signed-off-by: Kees Cook <keescook@chromium.org>
|
|
If get_unused_fd_flags() fails, the error handling is incomplete because
bprm->cred is already set to NULL, and therefore free_bprm will not
unlock the cred_guard_mutex. Note there are two error conditions which
end up here, one before and one after bprm->cred is cleared.
Fixes: b8a61c9e7b4a ("exec: Generic execfd support")
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Link: https://lore.kernel.org/r/AS8P193MB128517ADB5EFF29E04389EDAE4752@AS8P193MB1285.EURP193.PROD.OUTLOOK.COM
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
|
|
Consolidate the calls to allow_write_access()/fput() into a single
place, since we repeat this code pattern. Add comments around the
callers for the details on it.
Link: https://lore.kernel.org/r/202209161637.9EDAF6B18@keescook
Signed-off-by: Kees Cook <keescook@chromium.org>
|
|
Function name is wrong and the comment tells us nothing
Signed-off-by: Askar Safin <safinaskar@zohomail.com>
Link: https://lore.kernel.org/r/20240109030801.31827-1-safinaskar@zohomail.com
Signed-off-by: Kees Cook <keescook@chromium.org>
|
|
No point in allocating a new mm, counting arguments and environment
variables etc if we're just going to return ENOENT.
This patch does expose the fact that 'do_filp_open()' that execve() uses
is still unnecessarily expensive in the failure case, because it
allocates the 'struct file *' early, even if the path lookup (which is
heavily optimized) fails.
So that remains an unnecessary cost in the "no such executable" case,
but it's a separate issue. Regardless, I do not want to do _both_ a
filename_lookup() and a later do_filp_open() like the origin patch by
Josh Triplett did in [1].
Reported-by: Josh Triplett <josh@joshtriplett.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/lkml/5c7333ea4bec2fad1b47a8fa2db7c31e4ffc4f14.1663334978.git.josh@joshtriplett.org/ [1]
Link: https://lore.kernel.org/lkml/202209161637.9EDAF6B18@keescook/
Link: https://lore.kernel.org/lkml/CAHk-=wgznerM-xs+x+krDfE7eVBiy_HOam35rbsFMMOwvYuEKQ@mail.gmail.com/
Link: https://lore.kernel.org/lkml/CAHk-=whf9qLO8ipps4QhmS0BkM8mtWJhvnuDSdtw5gFjhzvKNA@mail.gmail.com/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux
Pull sysctl updates from Luis Chamberlain:
"To help make the move of sysctls out of kernel/sysctl.c not incur a
size penalty sysctl has been changed to allow us to not require the
sentinel, the final empty element on the sysctl array. Joel Granados
has been doing all this work.
In the v6.6 kernel we got the major infrastructure changes required to
support this. For v6.7 we had all arch/ and drivers/ modified to
remove the sentinel. For v6.8-rc1 we get a few more updates for fs/
directory only.
The kernel/ directory is left but we'll save that for v6.9-rc1 as
those patches are still being reviewed. After that we then can expect
also the removal of the no longer needed check for procname == NULL.
Let us recap the purpose of this work:
- this helps reduce the overall build time size of the kernel and run
time memory consumed by the kernel by about ~64 bytes per array
- the extra 64-byte penalty is no longer inncurred now when we move
sysctls out from kernel/sysctl.c to their own files
Thomas Weißschuh also sent a few cleanups, for v6.9-rc1 we expect to
see further work by Thomas Weißschuh with the constificatin of the
struct ctl_table.
Due to Joel Granados's work, and to help bring in new blood, I have
suggested for him to become a maintainer and he's accepted. So for
v6.9-rc1 I look forward to seeing him sent you a pull request for
further sysctl changes. This also removes Iurii Zaikin as a maintainer
as he has moved on to other projects and has had no time to help at
all"
* tag 'sysctl-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux:
sysctl: remove struct ctl_path
sysctl: delete unused define SYSCTL_PERM_EMPTY_DIR
coda: Remove the now superfluous sentinel elements from ctl_table array
sysctl: Remove the now superfluous sentinel elements from ctl_table array
fs: Remove the now superfluous sentinel elements from ctl_table array
cachefiles: Remove the now superfluous sentinel element from ctl_table array
sysclt: Clarify the results of selftest run
sysctl: Add a selftest for handling empty dirs
sysctl: Fix out of bounds access for empty sysctl registers
MAINTAINERS: Add Joel Granados as co-maintainer for proc sysctl
MAINTAINERS: remove Iurii Zaikin from proc sysctl
|
|
Pull header cleanups from Kent Overstreet:
"The goal is to get sched.h down to a type only header, so the main
thing happening in this patchset is splitting out various _types.h
headers and dependency fixups, as well as moving some things out of
sched.h to better locations.
This is prep work for the memory allocation profiling patchset which
adds new sched.h interdepencencies"
* tag 'header_cleanup-2024-01-10' of https://evilpiepirate.org/git/bcachefs: (51 commits)
Kill sched.h dependency on rcupdate.h
kill unnecessary thread_info.h include
Kill unnecessary kernel.h include
preempt.h: Kill dependency on list.h
rseq: Split out rseq.h from sched.h
LoongArch: signal.c: add header file to fix build error
restart_block: Trim includes
lockdep: move held_lock to lockdep_types.h
sem: Split out sem_types.h
uidgid: Split out uidgid_types.h
seccomp: Split out seccomp_types.h
refcount: Split out refcount_types.h
uapi/linux/resource.h: fix include
x86/signal: kill dependency on time.h
syscall_user_dispatch.h: split out *_types.h
mm_types_task.h: Trim dependencies
Split out irqflags_types.h
ipc: Kill bogus dependency on spinlock.h
shm: Slim down dependencies
workqueue: Split out workqueue_types.h
...
|
|
This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)
Remove sentinel elements ctl_table struct. Special attention was placed in
making sure that an empty directory for fs/verity was created when
CONFIG_FS_VERITY_BUILTIN_SIGNATURES is not defined. In this case we use the
register sysctl call that expects a size.
Signed-off-by: Joel Granados <j.granados@samsung.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
|
|
We're trying to get sched.h down to more or less just types only, not
code - rseq can live in its own header.
This helps us kill the dependency on preempt.h in sched.h.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
|
|
Cosmetic, but imho it makes the usage look more clear and simple, the new
helper doesn't require to initialize "t".
After this change while_each_thread() has only 3 users, and it is only
used in the do/while loops.
Link: https://lkml.kernel.org/r/20231030155710.GA9095@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
For the stack move happening in shift_arg_pages(), the move is happening
within the same VMA which spans the old and new ranges.
In case the aligned address happens to fall within that VMA, allow such
moves and don't abort the mremap alignment optimization.
In the regular non-stack mremap case, we cannot allow any such moves as
will end up destroying some part of the mapping (either the source of the
move, or part of the existing mapping). So just avoid it for stack moves.
Link: https://lkml.kernel.org/r/20230903151328.2981432-3-joel@joelfernandes.org
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The feature got retired in f1a7941243c1 ("mm: convert mm's rss stats into
percpu_counter"), but the patch failed to fully clean it up.
Link: https://lkml.kernel.org/r/20230823170556.2281747-1-mjguzik@gmail.com
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
- An extensive rework of kexec and crash Kconfig from Eric DeVolder
("refactor Kconfig to consolidate KEXEC and CRASH options")
- kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a
couple of macros to args.h")
- gdb feature work from Kuan-Ying Lee ("Add GDB memory helper
commands")
- vsprintf inclusion rationalization from Andy Shevchenko
("lib/vsprintf: Rework header inclusions")
- Switch the handling of kdump from a udev scheme to in-kernel
handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory
hot un/plug")
- Many singleton patches to various parts of the tree
* tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits)
document while_each_thread(), change first_tid() to use for_each_thread()
drivers/char/mem.c: shrink character device's devlist[] array
x86/crash: optimize CPU changes
crash: change crash_prepare_elf64_headers() to for_each_possible_cpu()
crash: hotplug support for kexec_load()
x86/crash: add x86 crash hotplug support
crash: memory and CPU hotplug sysfs attributes
kexec: exclude elfcorehdr from the segment digest
crash: add generic infrastructure for crash hotplug support
crash: move a few code bits to setup support of crash hotplug
kstrtox: consistently use _tolower()
kill do_each_thread()
nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse
scripts/bloat-o-meter: count weak symbol sizes
treewide: drop CONFIG_EMBEDDED
lockdep: fix static memory detection even more
lib/vsprintf: declare no_hash_pointers in sprintf.h
lib/vsprintf: split out sprintf() and friends
kernel/fork: stop playing lockless games for exe_file replacement
adfs: delete unused "union adfs_dirtail" definition
...
|
|
xchg originated in 6e399cd144d8 ("prctl: avoid using mmap_sem for exe_file
serialization"). While the commit message does not explain *why* the
change, I found the original submission [1] which ultimately claims it
cleans things up by removing dependency of exe_file on the semaphore.
However, fe69d560b5bd ("kernel/fork: always deny write access to current
MM exe_file") added a semaphore up/down cycle to synchronize the state of
exe_file against fork, defeating the point of the original change.
This is on top of semaphore trips already present both in the replacing
function and prctl (the only consumer).
Normally replacing exe_file does not happen for busy processes, thus
write-locking is not an impediment to performance in the intended use
case. If someone keeps invoking the routine for a busy processes they are
trying to play dirty and that's another reason to avoid any trickery.
As such I think the atomic here only adds complexity for no benefit.
Just write-lock around the replacement.
I also note that replacement races against the mapping check loop as
nothing synchronizes actual assignment with with said checks but I am not
addressing it in this patch. (Is the loop of any use to begin with?)
Link: https://lore.kernel.org/linux-mm/1424979417.10344.14.camel@stgolabs.net/ [1]
Link: https://lkml.kernel.org/r/20230814172140.1777161-1-mjguzik@gmail.com
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: "Christian Brauner (Microsoft)" <brauner@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Set the correct limits for vma_iter_prealloc() calls so that the maple
tree can be smarter about how many nodes are needed.
Link: https://lkml.kernel.org/r/20230724183157.3939892-11-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull fsnotify updates from Jan Kara:
- Support for fanotify events returning file handles for filesystems
not exportable via NFS
- Improved error handling exportfs functions
- Add missing FS_OPEN events when unusual open helpers are used
* tag 'fsnotify_for_v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
fsnotify: move fsnotify_open() hook into do_dentry_open()
exportfs: check for error return value from exportfs_encode_*()
fanotify: support reporting non-decodeable file handles
exportfs: allow exporting non-decodeable file handles to userspace
exportfs: add explicit flag to request non-decodeable file handles
exportfs: change connectable argument to bit flags
|
|
This modifies our user mode stack expansion code to always take the
mmap_lock for writing before modifying the VM layout.
It's actually something we always technically should have done, but
because we didn't strictly need it, we were being lazy ("opportunistic"
sounds so much better, doesn't it?) about things, and had this hack in
place where we would extend the stack vma in-place without doing the
proper locking.
And it worked fine. We just needed to change vm_start (or, in the case
of grow-up stacks, vm_end) and together with some special ad-hoc locking
using the anon_vma lock and the mm->page_table_lock, it all was fairly
straightforward.
That is, it was all fine until Ruihan Li pointed out that now that the
vma layout uses the maple tree code, we *really* don't just change
vm_start and vm_end any more, and the locking really is broken. Oops.
It's not actually all _that_ horrible to fix this once and for all, and
do proper locking, but it's a bit painful. We have basically three
different cases of stack expansion, and they all work just a bit
differently:
- the common and obvious case is the page fault handling. It's actually
fairly simple and straightforward, except for the fact that we have
something like 24 different versions of it, and you end up in a maze
of twisty little passages, all alike.
- the simplest case is the execve() code that creates a new stack.
There are no real locking concerns because it's all in a private new
VM that hasn't been exposed to anybody, but lockdep still can end up
unhappy if you get it wrong.
- and finally, we have GUP and page pinning, which shouldn't really be
expanding the stack in the first place, but in addition to execve()
we also use it for ptrace(). And debuggers do want to possibly access
memory under the stack pointer and thus need to be able to expand the
stack as a special case.
None of these cases are exactly complicated, but the page fault case in
particular is just repeated slightly differently many many times. And
ia64 in particular has a fairly complicated situation where you can have
both a regular grow-down stack _and_ a special grow-up stack for the
register backing store.
So to make this slightly more manageable, the bulk of this series is to
first create a helper function for the most common page fault case, and
convert all the straightforward architectures to it.
Thus the new 'lock_mm_and_find_vma()' helper function, which ends up
being used by x86, arm, powerpc, mips, riscv, alpha, arc, csky, hexagon,
loongarch, nios2, sh, sparc32, and xtensa. So we not only convert more
than half the architectures, we now have more shared code and avoid some
of those twisty little passages.
And largely due to this common helper function, the full diffstat of
this series ends up deleting more lines than it adds.
That still leaves eight architectures (ia64, m68k, microblaze, openrisc,
parisc, s390, sparc64 and um) that end up doing 'expand_stack()'
manually because they are doing something slightly different from the
normal pattern. Along with the couple of special cases in execve() and
GUP.
So there's a couple of patches that first create 'locked' helper
versions of the stack expansion functions, so that there's a obvious
path forward in the conversion. The execve() case is then actually
pretty simple, and is a nice cleanup from our old "grow-up stackls are
special, because at execve time even they grow down".
The #ifdef CONFIG_STACK_GROWSUP in that code just goes away, because
it's just more straightforward to write out the stack expansion there
manually, instead od having get_user_pages_remote() do it for us in some
situations but not others and have to worry about locking rules for GUP.
And the final step is then to just convert the remaining odd cases to a
new world order where 'expand_stack()' is called with the mmap_lock held
for reading, but where it might drop it and upgrade it to a write, only
to return with it held for reading (in the success case) or with it
completely dropped (in the failure case).
In the process, we remove all the stack expansion from GUP (where
dropping the lock wouldn't be ok without special rules anyway), and add
it in manually to __access_remote_vm() for ptrace().
Thanks to Adrian Glaubitz and Frank Scheiner who tested the ia64 cases.
Everything else here felt pretty straightforward, but the ia64 rules for
stack expansion are really quite odd and very different from everything
else. Also thanks to Vegard Nossum who caught me getting one of those
odd conditions entirely the wrong way around.
Anyway, I think I want to actually move all the stack expansion code to
a whole new file of its own, rather than have it split up between
mm/mmap.c and mm/memory.c, but since this will have to be backported to
the initial maple tree vma introduction anyway, I tried to keep the
patches _fairly_ minimal.
Also, while I don't think it's valid to expand the stack from GUP, the
final patch in here is a "warn if some crazy GUP user wants to try to
expand the stack" patch. That one will be reverted before the final
release, but it's left to catch any odd cases during the merge window
and release candidates.
Reported-by: Ruihan Li <lrh2000@pku.edu.cn>
* branch 'expand-stack':
gup: add warning if some caller would seem to want stack expansion
mm: always expand the stack with the mmap write lock held
execve: expand new process stack manually ahead of time
mm: make find_extend_vma() fail if write lock not held
powerpc/mm: convert coprocessor fault to lock_mm_and_find_vma()
mm/fault: convert remaining simple cases to lock_mm_and_find_vma()
arm/mm: Convert to using lock_mm_and_find_vma()
riscv/mm: Convert to using lock_mm_and_find_vma()
mips/mm: Convert to using lock_mm_and_find_vma()
powerpc/mm: Convert to using lock_mm_and_find_vma()
arm64/mm: Convert to using lock_mm_and_find_vma()
mm: make the page fault mmap locking killable
mm: introduce new 'lock_mm_and_find_vma()' page fault helper
|
|
This finishes the job of always holding the mmap write lock when
extending the user stack vma, and removes the 'write_locked' argument
from the vm helper functions again.
For some cases, we just avoid expanding the stack at all: drivers and
page pinning really shouldn't be extending any stacks. Let's see if any
strange users really wanted that.
It's worth noting that architectures that weren't converted to the new
lock_mm_and_find_vma() helper function are left using the legacy
"expand_stack()" function, but it has been changed to drop the mmap_lock
and take it for writing while expanding the vma. This makes it fairly
straightforward to convert the remaining architectures.
As a result of dropping and re-taking the lock, the calling conventions
for this function have also changed, since the old vma may no longer be
valid. So it will now return the new vma if successful, and NULL - and
the lock dropped - if the area could not be extended.
Tested-by: Vegard Nossum <vegard.nossum@oracle.com>
Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> # ia64
Tested-by: Frank Scheiner <frank.scheiner@web.de> # ia64
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
This is a small step towards a model where GUP itself would not expand
the stack, and any user that needs GUP to not look up existing mappings,
but actually expand on them, would have to do so manually before-hand,
and with the mm lock held for writing.
It turns out that execve() already did almost exactly that, except it
didn't take the mm lock at all (it's single-threaded so no locking
technically needed, but it could cause lockdep errors). And it only did
it for the CONFIG_STACK_GROWSUP case, since in that case GUP has
obviously never expanded the stack downwards.
So just make that CONFIG_STACK_GROWSUP case do the right thing with
locking, and enable it generally. This will eventually help GUP, and in
the meantime avoids a special case and the lockdep issue.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Make calls to extend_vma() and find_extend_vma() fail if the write lock
is required.
To avoid making this a flag-day event, this still allows the old
read-locking case for the trivial situations, and passes in a flag to
say "is it write-locked". That way write-lockers can say "yes, I'm
being careful", and legacy users will continue to work in all the common
cases until they have been fully converted to the new world order.
Co-Developed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
fsnotify_open() hook is called only from high level system calls
context and not called for the very many helpers to open files.
This may makes sense for many of the special file open cases, but it is
inconsistent with fsnotify_close() hook that is called for every last
fput() of on a file object with FMODE_OPENED.
As a result, it is possible to observe ACCESS, MODIFY and CLOSE events
without ever observing an OPEN event.
Fix this inconsistency by replacing all the fsnotify_open() hooks with
a single hook inside do_dentry_open().
If there are special cases that would like to opt-out of the possible
overhead of fsnotify() call in fsnotify_open(), they would probably also
want to avoid the overhead of fsnotify() call in the rest of the fsnotify
hooks, so they should be opening that file with the __FMODE_NONOTIFY flag.
However, in the majority of those cases, the s_fsnotify_connectors
optimization in fsnotify_parent() would be sufficient to avoid the
overhead of fsnotify() call anyway.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230611122429.1499617-1-amir73il@gmail.com>
|
|
The only instances of get_user_pages_remote() invocations which used the
vmas parameter were for a single page which can instead simply look up the
VMA directly. In particular:-
- __update_ref_ctr() looked up the VMA but did nothing with it so we simply
remove it.
- __access_remote_vm() was already using vma_lookup() when the original
lookup failed so by doing the lookup directly this also de-duplicates the
code.
We are able to perform these VMA operations as we already hold the
mmap_lock in order to be able to call get_user_pages_remote().
As part of this work we add get_user_page_vma_remote() which abstracts the
VMA lookup, error handling and decrementing the page reference count should
the VMA lookup fail.
This forms part of a broader set of patches intended to eliminate the vmas
parameter altogether.
[akpm@linux-foundation.org: avoid passing NULL to PTR_ERR]
Link: https://lkml.kernel.org/r/d20128c849ecdbf4dd01cc828fcec32127ed939a.1684350871.git.lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> (for arm64)
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com> (for s390)
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Christian König <christian.koenig@amd.com>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Sean Christopherson <seanjc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing updates from Steven Rostedt:
- User events are finally ready!
After lots of collaboration between various parties, we finally
locked down on a stable interface for user events that can also work
with user space only tracing.
This is implemented by telling the kernel (or user space library, but
that part is user space only and not part of this patch set), where
the variable is that the application uses to know if something is
listening to the trace.
There's also an interface to tell the kernel about these events,
which will show up in the /sys/kernel/tracing/events/user_events/
directory, where it can be enabled.
When it's enabled, the kernel will update the variable, to tell the
application to start writing to the kernel.
See https://lwn.net/Articles/927595/
- Cleaned up the direct trampolines code to simplify arm64 addition of
direct trampolines.
Direct trampolines use the ftrace interface but instead of jumping to
the ftrace trampoline, applications (mostly BPF) can register their
own trampoline for performance reasons.
- Some updates to the fprobe infrastructure. fprobes are more efficient
than kprobes, as it does not need to save all the registers that
kprobes on ftrace do. More work needs to be done before the fprobes
will be exposed as dynamic events.
- More updates to references to the obsolete path of
/sys/kernel/debug/tracing for the new /sys/kernel/tracing path.
- Add a seq_buf_do_printk() helper to seq_bufs, to print a large buffer
line by line instead of all at once.
There are users in production kernels that have a large data dump
that originally used printk() directly, but the data dump was larger
than what printk() allowed as a single print.
Using seq_buf() to do the printing fixes that.
- Add /sys/kernel/tracing/touched_functions that shows all functions
that was every traced by ftrace or a direct trampoline. This is used
for debugging issues where a traced function could have caused a
crash by a bpf program or live patching.
- Add a "fields" option that is similar to "raw" but outputs the fields
of the events. It's easier to read by humans.
- Some minor fixes and clean ups.
* tag 'trace-v6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (41 commits)
ring-buffer: Sync IRQ works before buffer destruction
tracing: Add missing spaces in trace_print_hex_seq()
ring-buffer: Ensure proper resetting of atomic variables in ring_buffer_reset_online_cpus
recordmcount: Fix memory leaks in the uwrite function
tracing/user_events: Limit max fault-in attempts
tracing/user_events: Prevent same address and bit per process
tracing/user_events: Ensure bit is cleared on unregister
tracing/user_events: Ensure write index cannot be negative
seq_buf: Add seq_buf_do_printk() helper
tracing: Fix print_fields() for __dyn_loc/__rel_loc
tracing/user_events: Set event filter_type from type
ring-buffer: Clearly check null ptr returned by rb_set_head_page()
tracing: Unbreak user events
tracing/user_events: Use print_format_fields() for trace output
tracing/user_events: Align structs with tabs for readability
tracing/user_events: Limit global user_event count
tracing/user_events: Charge event allocs to cgroups
tracing/user_events: Update documentation for ABI
tracing/user_events: Use write ABI in example
tracing/user_events: Add ABI self-test
...
|
|
During tracefs discussions it was decided instead of requiring a mapping
within a user-process to track the lifetime of memory descriptors we
should hook the appropriate calls. Do this by adding the minimal stubs
required for task fork, exec, and exit. Currently this is just a NOP.
Future patches will implement these calls fully.
Link: https://lkml.kernel.org/r/20230328235219.203-3-beaub@linux.microsoft.com
Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
Add explicit _lazy_tlb annotated functions for lazy tlb mm refcounting.
This makes the lazy tlb mm references more obvious, and allows the
refcounting scheme to be modified in later changes. There is no
functional change with this patch.
Link: https://lkml.kernel.org/r/20230203071837.1136453-3-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Daniel Verkamp has contributed a memfd series ("mm/memfd: add
F_SEAL_EXEC") which permits the setting of the memfd execute bit at
memfd creation time, with the option of sealing the state of the X
bit.
- Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
thread-safe for pmd unshare") which addresses a rare race condition
related to PMD unsharing.
- Several folioification patch serieses from Matthew Wilcox, Vishal
Moola, Sidhartha Kumar and Lorenzo Stoakes
- Johannes Weiner has a series ("mm: push down lock_page_memcg()")
which does perform some memcg maintenance and cleanup work.
- SeongJae Park has added DAMOS filtering to DAMON, with the series
"mm/damon/core: implement damos filter".
These filters provide users with finer-grained control over DAMOS's
actions. SeongJae has also done some DAMON cleanup work.
- Kairui Song adds a series ("Clean up and fixes for swap").
- Vernon Yang contributed the series "Clean up and refinement for maple
tree".
- Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
adds to MGLRU an LRU of memcgs, to improve the scalability of global
reclaim.
- David Hildenbrand has added some userfaultfd cleanup work in the
series "mm: uffd-wp + change_protection() cleanups".
- Christoph Hellwig has removed the generic_writepages() library
function in the series "remove generic_writepages".
- Baolin Wang has performed some maintenance on the compaction code in
his series "Some small improvements for compaction".
- Sidhartha Kumar is doing some maintenance work on struct page in his
series "Get rid of tail page fields".
- David Hildenbrand contributed some cleanup, bugfixing and
generalization of pte management and of pte debugging in his series
"mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with
swap PTEs".
- Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
flag in the series "Discard __GFP_ATOMIC".
- Sergey Senozhatsky has improved zsmalloc's memory utilization with
his series "zsmalloc: make zspage chain size configurable".
- Joey Gouly has added prctl() support for prohibiting the creation of
writeable+executable mappings.
The previous BPF-based approach had shortcomings. See "mm: In-kernel
support for memory-deny-write-execute (MDWE)".
- Waiman Long did some kmemleak cleanup and bugfixing in the series
"mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".
- T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
"mm: multi-gen LRU: improve".
- Jiaqi Yan has provided some enhancements to our memory error
statistics reporting, mainly by presenting the statistics on a
per-node basis. See the series "Introduce per NUMA node memory error
statistics".
- Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
regression in compaction via his series "Fix excessive CPU usage
during compaction".
- Christoph Hellwig does some vmalloc maintenance work in the series
"cleanup vfree and vunmap".
- Christoph Hellwig has removed block_device_operations.rw_page() in
ths series "remove ->rw_page".
- We get some maple_tree improvements and cleanups in Liam Howlett's
series "VMA tree type safety and remove __vma_adjust()".
- Suren Baghdasaryan has done some work on the maintainability of our
vm_flags handling in the series "introduce vm_flags modifier
functions".
- Some pagemap cleanup and generalization work in Mike Rapoport's
series "mm, arch: add generic implementation of pfn_valid() for
FLATMEM" and "fixups for generic implementation of pfn_valid()"
- Baoquan He has done some work to make /proc/vmallocinfo and
/proc/kcore better represent the real state of things in his series
"mm/vmalloc.c: allow vread() to read out vm_map_ram areas".
- Jason Gunthorpe rationalized the GUP system's interface to the rest
of the kernel in the series "Simplify the external interface for
GUP".
- SeongJae Park wishes to migrate people from DAMON's debugfs interface
over to its sysfs interface. To support this, we'll temporarily be
printing warnings when people use the debugfs interface. See the
series "mm/damon: deprecate DAMON debugfs interface".
- Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
and clean-ups" series.
- Huang Ying has provided a dramatic reduction in migration's TLB flush
IPI rates with the series "migrate_pages(): batch TLB flushing".
- Arnd Bergmann has some objtool fixups in "objtool warning fixes".
* tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits)
include/linux/migrate.h: remove unneeded externs
mm/memory_hotplug: cleanup return value handing in do_migrate_range()
mm/uffd: fix comment in handling pte markers
mm: change to return bool for isolate_movable_page()
mm: hugetlb: change to return bool for isolate_hugetlb()
mm: change to return bool for isolate_lru_page()
mm: change to return bool for folio_isolate_lru()
objtool: add UACCESS exceptions for __tsan_volatile_read/write
kmsan: disable ftrace in kmsan core code
kasan: mark addr_has_metadata __always_inline
mm: memcontrol: rename memcg_kmem_enabled()
sh: initialize max_mapnr
m68k/nommu: add missing definition of ARCH_PFN_OFFSET
mm: percpu: fix incorrect size in pcpu_obj_full_size()
maple_tree: reduce stack usage with gcc-9 and earlier
mm: page_alloc: call panic() when memoryless node allocation fails
mm: multi-gen LRU: avoid futile retries
migrate_pages: move THP/hugetlb migration support check to simplify code
migrate_pages: batch flushing TLB
migrate_pages: share more code between _unmap and _move
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
- Improve the scalability of the CFS bandwidth unthrottling logic with
large number of CPUs.
- Fix & rework various cpuidle routines, simplify interaction with the
generic scheduler code. Add __cpuidle methods as noinstr to objtool's
noinstr detection and fix boatloads of cpuidle bugs & quirks.
- Add new ABI: introduce MEMBARRIER_CMD_GET_REGISTRATIONS, to query
previously issued registrations.
- Limit scheduler slice duration to the sysctl_sched_latency period, to
improve scheduling granularity with a large number of SCHED_IDLE
tasks.
- Debuggability enhancement on sys_exit(): warn about disabled IRQs,
but also enable them to prevent a cascade of followup problems and
repeat warnings.
- Fix the rescheduling logic in prio_changed_dl().
- Micro-optimize cpufreq and sched-util methods.
- Micro-optimize ttwu_runnable()
- Micro-optimize the idle-scanning in update_numa_stats(),
select_idle_capacity() and steal_cookie_task().
- Update the RSEQ code & self-tests
- Constify various scheduler methods
- Remove unused methods
- Refine __init tags
- Documentation updates
- Misc other cleanups, fixes
* tag 'sched-core-2023-02-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (110 commits)
sched/rt: pick_next_rt_entity(): check list_entry
sched/deadline: Add more reschedule cases to prio_changed_dl()
sched/fair: sanitize vruntime of entity being placed
sched/fair: Remove capacity inversion detection
sched/fair: unlink misfit task from cpu overutilized
objtool: mem*() are not uaccess safe
cpuidle: Fix poll_idle() noinstr annotation
sched/clock: Make local_clock() noinstr
sched/clock/x86: Mark sched_clock() noinstr
x86/pvclock: Improve atomic update of last_value in pvclock_clocksource_read()
x86/atomics: Always inline arch_atomic64*()
cpuidle: tracing, preempt: Squash _rcuidle tracing
cpuidle: tracing: Warn about !rcu_is_watching()
cpuidle: lib/bug: Disable rcu_is_watching() during WARN/BUG
cpuidle: drivers: firmware: psci: Dont instrument suspend code
KVM: selftests: Fix build of rseq test
exit: Detect and fix irq disabled state in oops
cpuidle, arm64: Fix the ARM64 cpuidle logic
cpuidle: mvebu: Fix duplicate flags assignment
sched/fair: Limit sched slice duration
...
|
|
Replace direct modifications to vma->vm_flags with calls to modifier
functions to be able to track flag changes and to keep vma locking
correctness.
[akpm@linux-foundation.org: fix drivers/misc/open-dice.c, per Hyeonggon Yoo]
Link: https://lkml.kernel.org/r/20230126193752.297968-5-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjun Roy <arjunroy@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Minchan Kim <minchan@google.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Oskolkov <posk@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Introduce shrink_vma() which uses the vma_prepare() and vma_complete()
functions to reduce the vma coverage.
Convert shift_arg_pages() to use expand_vma() and the new shrink_vma()
function. Remove support from __vma_adjust() to reduce a vma size since
shift_arg_pages() is the only user that shrinks a VMA in this way.
Link: https://lkml.kernel.org/r/20230120162650.984577-46-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Use the abstracted locking and maple tree operations. Since __split_vma()
is the only user of the __vma_adjust() function to use the insert
argument, drop that argument. Remove the NULL passed through from
fs/exec's shift_arg_pages() and mremap() at the same time.
Link: https://lkml.kernel.org/r/20230120162650.984577-44-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Change the vma_adjust() function definition to accept the vma iterator and
pass it through to __vma_adjust().
Update fs/exec to use the new vma_adjust() function parameters.
Update mm/mremap to use the new vma_adjust() function parameters.
Revert the __split_vma() calls back from __vma_adjust() to vma_adjust()
and pass through the vma iterator.
Link: https://lkml.kernel.org/r/20230120162650.984577-37-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Use the vma iterator so that the iterator can be invalidated or updated to
avoid each caller doing so.
Link: https://lkml.kernel.org/r/20230120162650.984577-18-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Convert to struct mnt_idmap.
Remove legacy file_mnt_user_ns() and mnt_user_ns().
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
|
|
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
|
|
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
|
|
This feature allows the scheduler to expose a per-memory map concurrency
ID to user-space. This concurrency ID is within the possible cpus range,
and is temporarily (and uniquely) assigned while threads are actively
running within a memory map. If a memory map has fewer threads than
cores, or is limited to run on few cores concurrently through sched
affinity or cgroup cpusets, the concurrency IDs will be values close
to 0, thus allowing efficient use of user-space memory for per-cpu
data structures.
This feature is meant to be exposed by a new rseq thread area field.
The primary purpose of this feature is to do the heavy-lifting needed
by memory allocators to allow them to use per-cpu data structures
efficiently in the following situations:
- Single-threaded applications,
- Multi-threaded applications on large systems (many cores) with limited
cpu affinity mask,
- Multi-threaded applications on large systems (many cores) with
restricted cgroup cpuset per container.
One of the key concern from scheduler maintainers is the overhead
associated with additional spin locks or atomic operations in the
scheduler fast-path. This is why the following optimization is
implemented.
On context switch between threads belonging to the same memory map,
transfer the mm_cid from prev to next without any atomic ops. This
takes care of use-cases involving frequent context switch between
threads belonging to the same memory map.
Additional optimizations can be done if the spin locks added when
context switching between threads belonging to different memory maps end
up being a performance bottleneck. Those are left out of this patch
though. A performance impact would have to be clearly demonstrated to
justify the added complexity.
The credit goes to Paul Turner (Google) for the original virtual cpu id
idea. This feature is implemented based on the discussions with Paul
Turner and Peter Oskolkov (Google), but I took the liberty to implement
scheduler fast-path optimizations and my own NUMA-awareness scheme. The
rumor has it that Google have been running a rseq vcpu_id extension
internally in production for a year. The tcmalloc source code indeed has
comments hinting at a vcpu_id prototype extension to the rseq system
call [1].
The following benchmarks do not show any significant overhead added to
the scheduler context switch by this feature:
* perf bench sched messaging (process)
Baseline: 86.5±0.3 ms
With mm_cid: 86.7±2.6 ms
* perf bench sched messaging (threaded)
Baseline: 84.3±3.0 ms
With mm_cid: 84.7±2.6 ms
* hackbench (process)
Baseline: 82.9±2.7 ms
With mm_cid: 82.9±2.9 ms
* hackbench (threaded)
Baseline: 85.2±2.6 ms
With mm_cid: 84.4±2.9 ms
[1] https://github.com/google/tcmalloc/blob/master/tcmalloc/internal/linux_syscall_support.h#L26
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221122203932.231377-8-mathieu.desnoyers@efficios.com
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping
Pull vfsuid updates from Christian Brauner:
"Last cycle we introduced the vfs{g,u}id_t types and associated helpers
to gain type safety when dealing with idmapped mounts. That initial
work already converted a lot of places over but there were still some
left,
This converts all remaining places that still make use of non-type
safe idmapping helpers to rely on the new type safe vfs{g,u}id based
helpers.
Afterwards it removes all the old non-type safe helpers"
* tag 'fs.vfsuid.conversion.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping:
fs: remove unused idmapping helpers
ovl: port to vfs{g,u}id_t and associated helpers
fuse: port to vfs{g,u}id_t and associated helpers
ima: use type safe idmapping helpers
apparmor: use type safe idmapping helpers
caps: use type safe idmapping helpers
fs: use type safe idmapping helpers
mnt_idmapping: add missing helpers
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull execve updates from Kees Cook:
"Most are small refactorings and bug fixes, but three things stand out:
switching timens (which got reverted before) looks solid now,
FOLL_FORCE has been removed (no failures seen yet across several weeks
in -next), and some whitespace cleanups (which are long overdue).
- Add timens support (when switching mm). This version has survived
in -next for the entire cycle (Andrei Vagin)
- Various small bug fixes, refactoring, and readability improvements
(Bernd Edlinger, Rolf Eike Beer, Bo Liu, Li Zetao Liu Shixin)
- Remove FOLL_FORCE for stack setup (Kees Cook)
- Whitespace cleanups (Rolf Eike Beer, Kees Cook)"
* tag 'execve-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
binfmt_misc: fix shift-out-of-bounds in check_special_flags
binfmt: Fix error return code in load_elf_fdpic_binary()
exec: Remove FOLL_FORCE for stack setup
binfmt_elf: replace IS_ERR() with IS_ERR_VALUE()
binfmt_elf: simplify error handling in load_elf_phdrs()
binfmt_elf: fix documented return value for load_elf_phdrs()
exec: simplify initial stack size expansion
binfmt: Fix whitespace issues
exec: Add comments on check_unsafe_exec() fs counting
ELF uapi: add spaces before '{'
selftests/timens: add a test for vfork+exit
fs/exec: switch timens when a task gets a new mm
|
|
It does not appear that FOLL_FORCE should be needed for setting up the
stack pages. They are allocated using the nascent brpm->vma, which was
newly created with VM_STACK_FLAGS, which an arch can override, but they
all appear to include VM_WRITE | VM_MAYWRITE. Remove FOLL_FORCE.
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-mm@kvack.org
Link: https://lore.kernel.org/lkml/202211171439.CDE720EAD@keescook/
Signed-off-by: Kees Cook <keescook@chromium.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc hotfixes from Andrew Morton:
"Eight fix pre-6.0 bugs and the remainder address issues which were
introduced in the 6.1-rc merge cycle, or address issues which aren't
considered sufficiently serious to warrant a -stable backport"
* tag 'mm-hotfixes-stable-2022-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (23 commits)
mm: multi-gen LRU: move lru_gen_add_mm() out of IRQ-off region
lib: maple_tree: remove unneeded initialization in mtree_range_walk()
mmap: fix remap_file_pages() regression
mm/shmem: ensure proper fallback if page faults
mm/userfaultfd: replace kmap/kmap_atomic() with kmap_local_page()
x86: fortify: kmsan: fix KMSAN fortify builds
x86: asm: make sure __put_user_size() evaluates pointer once
Kconfig.debug: disable CONFIG_FRAME_WARN for KMSAN by default
x86/purgatory: disable KMSAN instrumentation
mm: kmsan: export kmsan_copy_page_meta()
mm: migrate: fix return value if all subpages of THPs are migrated successfully
mm/uffd: fix vma check on userfault for wp
mm: prep_compound_tail() clear page->private
mm,madvise,hugetlb: fix unexpected data loss with MADV_DONTNEED on hugetlbfs
mm/page_isolation: fix clang deadcode warning
fs/ext4/super.c: remove unused `deprecated_msg'
ipc/msg.c: fix percpu_counter use after free
memory tier, sysfs: rename attribute "nodes" to "nodelist"
MAINTAINERS: git://github.com -> https://github.com for nilfs2
mm/kmemleak: prevent soft lockup in kmemleak_scan()'s object iteration loops
...
|
|
lru_gen_add_mm() has been added within an IRQ-off region in the commit
mentioned below. The other invocations of lru_gen_add_mm() are not within
an IRQ-off region.
The invocation within IRQ-off region is problematic on PREEMPT_RT because
the function is using a spin_lock_t which must not be used within
IRQ-disabled regions.
The other invocations of lru_gen_add_mm() occur while
task_struct::alloc_lock is acquired. Move lru_gen_add_mm() after
interrupts are enabled and before task_unlock().
Link: https://lkml.kernel.org/r/20221026134830.711887-1-bigeasy@linutronix.de
Fixes: bd74fdaea1460 ("mm: multi-gen LRU: support page table walks")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Yu Zhao <yuzhao@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
We already ported most parts and filesystems over for v6.0 to the new
vfs{g,u}id_t type and associated helpers for v6.0. Convert the remaining
places so we can remove all the old helpers.
This is a non-functional change.
Reviewed-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
|
|
I had a hard time trying to understand completely why it is using vm_end in
one side of the expression and vm_start in the other one, and using
something in the "if" clause that is not an exact copy of what is used
below. The whole point is that the stack_size variable that was used in the
"if" clause is the difference between vm_start and vm_end, which is not far
away but makes this thing harder to read than it must be.
Signed-off-by: Rolf Eike Beer <eb@emlix.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/2017429.gqNitNVd0C@mobilepool36.emlix.com
|
|
Fix the annoying whitespace issues that have been following these files
around for years.
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Link: https://lore.kernel.org/r/20221018071350.never.230-kees@kernel.org
|
|
Add some comments about what the fs counting is doing in
check_unsafe_exec() and how it relates to the call graph.
Specifically, we can't force an unshare of the fs because
of at least Chrome:
https://lore.kernel.org/lkml/86CE201B-5632-4BB7-BCF6-7CB2C2895409@chromium.org/
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Link: https://lore.kernel.org/r/20221018071537.never.662-kees@kernel.org
|
|
Changing a time namespace requires remapping a vvar page, so we don't want
to allow doing that if any other tasks can use the same mm.
Currently, we install a time namespace when a task is created with a new
vm. exec() is another case when a task gets a new mm and so it can switch
a time namespace safely, but it isn't handled now.
One more issue of the current interface is that clone() with CLONE_VM isn't
allowed if the current task has unshared a time namespace
(timens_for_children doesn't match the current timens).
Both these issues make some inconvenience for users. For example, Alexey
and Florian reported that posix_spawn() uses vfork+exec and this pattern
doesn't work with time namespaces due to the both described issues.
LXC needed to workaround the exec() issue by calling setns.
In the commit 133e2d3e81de5 ("fs/exec: allow to unshare a time namespace on
vfork+exec"), we tried to fix these issues with minimal impact on UAPI. But
it adds extra complexity and some undesirable side effects. Eric suggested
fixing the issues properly because here are all the reasons to suppose that
there are no users that depend on the old behavior.
Cc: Alexey Izbyshev <izbyshev@ispras.ru>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com>
Origin-author: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220921003120.209637-1-avagin@google.com
|
|
unshare_sighand should only access oldsighand->action
while holding oldsighand->siglock, to make sure that
newsighand->action is in a consistent state.
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Cc: stable@vger.kernel.org
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/AM8PR10MB470871DEBD1DED081F9CC391E4389@AM8PR10MB4708.EURPRD10.PROD.OUTLOOK.COM
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Yu Zhao's Multi-Gen LRU patches are here. They've been under test in
linux-next for a couple of months without, to my knowledge, any
negative reports (or any positive ones, come to that).
- Also the Maple Tree from Liam Howlett. An overlapping range-based
tree for vmas. It it apparently slightly more efficient in its own
right, but is mainly targeted at enabling work to reduce mmap_lock
contention.
Liam has identified a number of other tree users in the kernel which
could be beneficially onverted to mapletrees.
Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
at [1]. This has yet to be addressed due to Liam's unfortunately
timed vacation. He is now back and we'll get this fixed up.
- Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
clang-generated instrumentation to detect used-unintialized bugs down
to the single bit level.
KMSAN keeps finding bugs. New ones, as well as the legacy ones.
- Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
memory into THPs.
- Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to
support file/shmem-backed pages.
- userfaultfd updates from Axel Rasmussen
- zsmalloc cleanups from Alexey Romanov
- cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and
memory-failure
- Huang Ying adds enhancements to NUMA balancing memory tiering mode's
page promotion, with a new way of detecting hot pages.
- memcg updates from Shakeel Butt: charging optimizations and reduced
memory consumption.
- memcg cleanups from Kairui Song.
- memcg fixes and cleanups from Johannes Weiner.
- Vishal Moola provides more folio conversions
- Zhang Yi removed ll_rw_block() :(
- migration enhancements from Peter Xu
- migration error-path bugfixes from Huang Ying
- Aneesh Kumar added ability for a device driver to alter the memory
tiering promotion paths. For optimizations by PMEM drivers, DRM
drivers, etc.
- vma merging improvements from Jakub Matěn.
- NUMA hinting cleanups from David Hildenbrand.
- xu xin added aditional userspace visibility into KSM merging
activity.
- THP & KSM code consolidation from Qi Zheng.
- more folio work from Matthew Wilcox.
- KASAN updates from Andrey Konovalov.
- DAMON cleanups from Kaixu Xia.
- DAMON work from SeongJae Park: fixes, cleanups.
- hugetlb sysfs cleanups from Muchun Song.
- Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.
Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1]
* tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits)
hugetlb: allocate vma lock for all sharable vmas
hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer
hugetlb: fix vma lock handling during split vma and range unmapping
mglru: mm/vmscan.c: fix imprecise comments
mm/mglru: don't sync disk for each aging cycle
mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol
mm: memcontrol: use do_memsw_account() in a few more places
mm: memcontrol: deprecate swapaccounting=0 mode
mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled
mm/secretmem: remove reduntant return value
mm/hugetlb: add available_huge_pages() func
mm: remove unused inline functions from include/linux/mm_inline.h
selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory
selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd
selftests/vm: add thp collapse shmem testing
selftests/vm: add thp collapse file and tmpfs testing
selftests/vm: modularize thp collapse memory operations
selftests/vm: dedup THP helpers
mm/khugepaged: add tracepoint to hpage_collapse_scan_file()
mm/madvise: add file and shmem support to MADV_COLLAPSE
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull ucounts update from Eric Biederman:
"Split rlimit and ucount values and max values
After the ucount rlimit code was merged a bunch of small but
siginificant bugs were found and fixed. At the time it was realized
that part of the problem was that while the ucount rlimits were very
similar to the oridinary ucounts (in being nested counts with limits)
the semantics were slightly different and the code would be less error
prone if there was less sharing.
This is the long awaited cleanup that should hopefully keep things
more comprehensible and less error prone for whoever needs to touch
that code next"
* tag 'ucount-rlimits-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
ucounts: Split rlimit and ucount values and max values
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull file_inode() updates from Al Vrio:
"whack-a-mole: cropped up open-coded file_inode() uses..."
* tag 'pull-file_inode' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
orangefs: use ->f_mapping
_nfs42_proc_copy(): use ->f_mapping instead of file_inode()->i_mapping
dma_buf: no need to bother with file_inode()->i_mapping
nfs_finish_open(): don't open-code file_inode()
bprm_fill_uid(): don't open-code file_inode()
sgx: use ->f_mapping...
exfat_iterate(): don't open-code file_inode(file)
ibmvmc: don't open-code file_inode()
|
|
In commit 19e8b701e258 ("a.out: Stop building a.out/osf1 support on
alpha and m68k") the last users of a.out were disabled.
As nothing has turned up to cause this change to be reverted, let's
remove the code implementing a.out support as well.
There may be userspace users of the uapi bits left so the uapi
headers have been left untouched.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Arnd Bergmann <arnd@arndb.de> # arm defconfigs
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/871qrx3hq3.fsf@email.froward.int.ebiederm.org
|
|
Remove a use of the vm_next list by doing the initial lookup with the VMA
iterator and then using it to find the next entry.
Link: https://lkml.kernel.org/r/20220906194824.2110408-42-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
By using the maple tree and the maple tree state, the vmacache is no
longer beneficial and is complicating the VMA code. Remove the vmacache
to reduce the work in keeping it up to date and code complexity.
Link: https://lkml.kernel.org/r/20220906194824.2110408-26-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
To further exploit spatial locality, the aging prefers to walk page tables
to search for young PTEs and promote hot pages. A kill switch will be
added in the next patch to disable this behavior. When disabled, the
aging relies on the rmap only.
NB: this behavior has nothing similar with the page table scanning in the
2.4 kernel [1], which searches page tables for old PTEs, adds cold pages
to swapcache and unmaps them.
To avoid confusion, the term "iteration" specifically means the traversal
of an entire mm_struct list; the term "walk" will be applied to page
tables and the rmap, as usual.
An mm_struct list is maintained for each memcg, and an mm_struct follows
its owner task to the new memcg when this task is migrated. Given an
lruvec, the aging iterates lruvec_memcg()->mm_list and calls
walk_page_range() with each mm_struct on this list to promote hot pages
before it increments max_seq.
When multiple page table walkers iterate the same list, each of them gets
a unique mm_struct; therefore they can run concurrently. Page table
walkers ignore any misplaced pages, e.g., if an mm_struct was migrated,
pages it left in the previous memcg will not be promoted when its current
memcg is under reclaim. Similarly, page table walkers will not promote
pages from nodes other than the one under reclaim.
This patch uses the following optimizations when walking page tables:
1. It tracks the usage of mm_struct's between context switches so that
page table walkers can skip processes that have been sleeping since
the last iteration.
2. It uses generational Bloom filters to record populated branches so
that page table walkers can reduce their search space based on the
query results, e.g., to skip page tables containing mostly holes or
misplaced pages.
3. It takes advantage of the accessed bit in non-leaf PMD entries when
CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG=y.
4. It does not zigzag between a PGD table and the same PMD table
spanning multiple VMAs. IOW, it finishes all the VMAs within the
range of the same PMD table before it returns to a PGD table. This
improves the cache performance for workloads that have large
numbers of tiny VMAs [2], especially when CONFIG_PGTABLE_LEVELS=5.
Server benchmark results:
Single workload:
fio (buffered I/O): no change
Single workload:
memcached (anon): +[8, 10]%
Ops/sec KB/sec
patch1-7: 1147696.57 44640.29
patch1-8: 1245274.91 48435.66
Configurations:
no change
Client benchmark results:
kswapd profiles:
patch1-7
48.16% lzo1x_1_do_compress (real work)
8.20% page_vma_mapped_walk (overhead)
7.06% _raw_spin_unlock_irq
2.92% ptep_clear_flush
2.53% __zram_bvec_write
2.11% do_raw_spin_lock
2.02% memmove
1.93% lru_gen_look_around
1.56% free_unref_page_list
1.40% memset
patch1-8
49.44% lzo1x_1_do_compress (real work)
6.19% page_vma_mapped_walk (overhead)
5.97% _raw_spin_unlock_irq
3.13% get_pfn_folio
2.85% ptep_clear_flush
2.42% __zram_bvec_write
2.08% do_raw_spin_lock
1.92% memmove
1.44% alloc_zspage
1.36% memset
Configurations:
no change
Thanks to the following developers for their efforts [3].
kernel test robot <lkp@intel.com>
[1] https://lwn.net/Articles/23732/
[2] https://llvm.org/docs/ScudoHardenedAllocator.html
[3] https://lore.kernel.org/r/202204160827.ekEARWQo-lkp@intel.com/
Link: https://lkml.kernel.org/r/20220918080010.2920238-9-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Brian Geffon <bgeffon@google.com>
Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Acked-by: Steven Barrett <steven@liquorix.net>
Acked-by: Suleiman Souhlal <suleiman@google.com>
Tested-by: Daniel Byrne <djbyrne@mtu.edu>
Tested-by: Donald Carr <d@chaos-reins.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
Tested-by: Shuang Zhai <szhai2@cs.rochester.edu>
Tested-by: Sofia Trinh <sofia.trinh@edi.works>
Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michael Larabel <Michael@MichaelLarabel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This reverts commit 133e2d3e81de5d9706cab2dd1d52d231c27382e5.
Alexey pointed out a few undesirable side effects of the reverted change.
First, it doesn't take into account that CLONE_VFORK can be used with
CLONE_THREAD. Second, a child process doesn't enter a target time name-space,
if its parent dies before the child calls exec. It happens because the parent
clears vfork_done.
Eric W. Biederman suggests installing a time namespace as a task gets a new mm.
It includes all new processes cloned without CLONE_VM and all tasks that call
exec(). This is an user API change, but we think there aren't users that depend
on the old behavior.
It is too late to make such changes in this release, so let's roll back
this patch and introduce the right one in the next release.
Cc: Alexey Izbyshev <izbyshev@ispras.ru>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220913102551.1121611-3-avagin@google.com
|
|
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull execve fix from Kees Cook:
- Replace remaining kmap() uses with kmap_local_page() (Fabio M. De
Francesco)
* tag 'execve-v6.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
exec: Replace kmap{,_atomic}() with kmap_local_page()
|
|
The use of kmap() and kmap_atomic() are being deprecated in favor of
kmap_local_page().
There are two main problems with kmap(): (1) It comes with an overhead as
mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap’s pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.
With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and are still valid.
Since the use of kmap_local_page() in exec.c is safe, it should be
preferred everywhere in exec.c.
As said, since kmap_local_page() can be also called from atomic context,
and since remove_arg_zero() doesn't (and shouldn't ever) rely on an
implicit preempt_disable(), this function can also safely replace
kmap_atomic().
Therefore, replace kmap() and kmap_atomic() with kmap_local_page() in
fs/exec.c.
Tested with xfstests on a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel
with HIGHMEM64GB enabled.
Cc: Eric W. Biederman <ebiederm@xmission.com>
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220803182856.28246-1-fmdefrancesco@gmail.com
|
|
Commit 55e8c8eb2c7b ("posix-cpu-timers: Store a reference to a pid not a
task") started looking up tasks by PID when deleting a CPU timer.
When a non-leader thread calls execve, it will switch PIDs with the leader
process. Then, as it calls exit_itimers, posix_cpu_timer_del cannot find
the task because the timer still points out to the old PID.
That means that armed timers won't be disarmed, that is, they won't be
removed from the timerqueue_list. exit_itimers will still release their
memory, and when that list is later processed, it leads to a
use-after-free.
Clean up the timers from the de-threaded task before freeing them. This
prevents a reported use-after-free.
Fixes: 55e8c8eb2c7b ("posix-cpu-timers: Store a reference to a pid not a task")
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220809170751.164716-1-cascardo@canonical.com
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull execve updates from Kees Cook:
- Allow unsharing time namespace on vfork+exec (Andrei Vagin)
- Replace usage of deprecated kmap APIs (Fabio M. De Francesco)
- Fix spelling mistake (Zhang Jiaming)
* tag 'execve-v5.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
exec: Call kmap_local_page() in copy_string_kernel()
exec: Fix a spelling mistake
selftests/timens: add a test for vfork+exit
fs/exec: allow to unshare a time namespace on vfork+exec
|
|
The use of kmap_atomic() is being deprecated in favor of kmap_local_page().
With kmap_local_page(), the mappings are per thread, CPU local and not
globally visible. Furthermore, the mappings can be acquired from any
context (including interrupts).
Therefore, replace kmap_atomic() with kmap_local_page() in
copy_string_kernel(). Instead of open-coding local mapping + memcpy(),
use memcpy_to_page(). Delete a redundant call to flush_dcache_page().
Tested with xfstests on a QEMU/ KVM x86_32 VM, 6GB RAM, booting a kernel
with HIGHMEM64GB enabled.
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220724212523.13317-1-fmdefrancesco@gmail.com
|
|
As Chris explains, the comment above exit_itimers() is not correct,
we can race with proc_timers_seq_ops. Change exit_itimers() to clear
signal->posix_timers with ->siglock held.
Cc: <stable@vger.kernel.org>
Reported-by: chris@accessvector.net
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Change 'wont't' to 'won't'.
Signed-off-by: Zhang Jiaming <jiaming@nfschina.com>
Reviewed-by: Souptick Joarder (HPE) <jrdr.linux@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220629072932.27506-1-jiaming@nfschina.com
|
|
Right now, a new process can't be forked in another time namespace
if it shares mm with its parent. It is prohibited, because each time
namespace has its own vvar page that is mapped into a process address
space.
When a process calls exec, it gets a new mm and so it could be "legal"
to switch time namespace in that case. This was not implemented and
now if we want to do this, we need to add another clone flag to not
break backward compatibility.
We don't have any user requests to switch times on exec except the
vfork+exec combination, so there is no reason to add a new clone flag.
As for vfork+exec, this should be safe to allow switching timens with
the current clone flag. Right now, vfork (CLONE_VFORK | CLONE_VM) fails
if a child is forked into another time namespace. With this change,
vfork creates a new process in parent's timens, and the following exec
does the actual switch to the target time namespace.
Suggested-by: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220613060723.197407-1-avagin@gmail.com
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull kthread updates from Eric Biederman:
"This updates init and user mode helper tasks to be ordinary user mode
tasks.
Commit 40966e316f86 ("kthread: Ensure struct kthread is present for
all kthreads") caused init and the user mode helper threads that call
kernel_execve to have struct kthread allocated for them. This struct
kthread going away during execve in turned made a use after free of
struct kthread possible.
Here, commit 343f4c49f243 ("kthread: Don't allocate kthread_struct for
init and umh") is enough to fix the use after free and is simple
enough to be backportable.
The rest of the changes pass struct kernel_clone_args to clean things
up and cause the code to make sense.
In making init and the user mode helpers tasks purely user mode tasks
I ran into two complications. The function task_tick_numa was
detecting tasks without an mm by testing for the presence of
PF_KTHREAD. The initramfs code in populate_initrd_image was using
flush_delayed_fput to ensuere the closing of all it's file descriptors
was complete, and flush_delayed_fput does not work in a userspace
thread.
I have looked and looked and more complications and in my code review
I have not found any, and neither has anyone else with the code
sitting in linux-next"
* tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
sched: Update task_tick_numa to ignore tasks without an mm
fork: Stop allowing kthreads to call execve
fork: Explicitly set PF_KTHREAD
init: Deal with the init process being a user mode process
fork: Generalize PF_IO_WORKER handling
fork: Explicity test for idle tasks in copy_thread
fork: Pass struct kernel_clone_args into copy_thread
kthread: Don't allocate kthread_struct for init and umh
|
|
Since the semantics of maximum rlimit values are different, it would be
better not to mix ucount and rlimit values. This will prevent the error
of using inc_count/dec_ucount for rlimit parameters.
This patch also renames the functions to emphasize the lack of
connection between rlimit and ucount.
v3:
- Fix BUG:KASAN:use-after-free_in_dec_ucount.
v2:
- Fix the array-index-out-of-bounds that was found by the lkp project.
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Link: https://lkml.kernel.org/r/20220518171730.l65lmnnjtnxnftpq@example.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
|
|
Patch series "mm/mprotect: avoid unnecessary TLB flushes", v6.
This patchset is intended to remove unnecessary TLB flushes during
mprotect() syscalls. Once this patch-set make it through, similar and
further optimizations for MADV_COLD and userfaultfd would be possible.
Basically, there are 3 optimizations in this patch-set:
1. Use TLB batching infrastructure to batch flushes across VMAs and do
better/fewer flushes. This would also be handy for later userfaultfd
enhancements.
2. Avoid unnecessary TLB flushes. This optimization is the one that
provides most of the performance benefits. Unlike previous versions,
we now only avoid flushes that would not result in spurious
page-faults.
3. Avoiding TLB flushes on change_huge_pmd() that are only needed to
prevent the A/D bits from changing.
Andrew asked for some benchmark numbers. I do not have an easy
determinate macrobenchmark in which it is easy to show benefit. I
therefore ran a microbenchmark: a loop that does the following on
anonymous memory, just as a sanity check to see that time is saved by
avoiding TLB flushes. The loop goes:
mprotect(p, PAGE_SIZE, PROT_READ)
mprotect(p, PAGE_SIZE, PROT_READ|PROT_WRITE)
*p = 0; // make the page writable
The test was run in KVM guest with 1 or 2 threads (the second thread was
busy-looping). I measured the time (cycles) of each operation:
1 thread 2 threads
mmots +patch mmots +patch
PROT_READ 3494 2725 (-22%) 8630 7788 (-10%)
PROT_READ|WRITE 3952 2724 (-31%) 9075 2865 (-68%)
[ mmots = v5.17-rc6-mmots-2022-03-06-20-38 ]
The exact numbers are really meaningless, but the benefit is clear. There
are 2 interesting results though.
(1) PROT_READ is cheaper, while one can expect it not to be affected.
This is presumably due to TLB miss that is saved
(2) Without memory access (*p = 0), the speedup of the patch is even
greater. In that scenario mprotect(PROT_READ) also avoids the TLB flush.
As a result both operations on the patched kernel take roughly ~1500
cycles (with either 1 or 2 threads), whereas on mmotm their cost is as
high as presented in the table.
This patch (of 3):
change_pXX_range() currently does not use mmu_gather, but instead
implements its own deferred TLB flushes scheme. This both complicates the
code, as developers need to be aware of different invalidation schemes,
and prevents opportunities to avoid TLB flushes or perform them in finer
granularity.
The use of mmu_gather for modified PTEs has benefits in various scenarios
even if pages are not released. For instance, if only a single page needs
to be flushed out of a range of many pages, only that page would be
flushed. If a THP page is flushed, on x86 a single TLB invlpg instruction
can be used instead of 512 instructions (or a full TLB flush, which would
Linux would actually use by default). mprotect() over multiple VMAs
requires a single flush.
Use mmu_gather in change_pXX_range(). As the pages are not released, only
record the flushed range using tlb_flush_pXX_range().
Handle THP similarly and get rid of flush_cache_range() which becomes
redundant since tlb_start_vma() calls it when needed.
Link: https://lkml.kernel.org/r/20220401180821.1986781-1-namit@vmware.com
Link: https://lkml.kernel.org/r/20220401180821.1986781-2-namit@vmware.com
Signed-off-by: Nadav Amit <namit@vmware.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Nick Piggin <npiggin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Now that kernel_execve is no longer called from kernel threads stop
supporting kernel threads calling kernel_execve.
Remove the code for converting a kthread to a normal thread in execve.
Document the restriction that kthreads may not call kernel_execve by
having kernel_execve fail if called by a kthread.
Link: https://lkml.kernel.org/r/20220506141512.516114-7-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
If kthread_is_per_cpu runs concurrently with free_kthread_struct the
kthread_struct that was just freed may be read from.
This bug was introduced by commit 40966e316f86 ("kthread: Ensure
struct kthread is present for all kthreads"). When kthread_struct
started to be allocated for all tasks that have PF_KTHREAD set. This
in turn required the kthread_struct to be freed in kernel_execve and
violated the assumption that kthread_struct will have the same
lifetime as the task.
Looking a bit deeper this only applies to callers of kernel_execve
which is just the init process and the user mode helper processes.
These processes really don't want to be kernel threads but are for
historical reasons. Mostly that copy_thread does not know how to take
a kernel mode function to the process with for processes without
PF_KTHREAD or PF_IO_WORKER set.
Solve this by not allocating kthread_struct for the init process and
the user mode helper processes.
This is done by adding a kthread member to struct kernel_clone_args.
Setting kthread in fork_idle and kernel_thread. Adding
user_mode_thread that works like kernel_thread except it does not set
kthread. In fork only allocating the kthread_struct if .kthread is set.
I have looked at kernel/kthread.c and since commit 40966e316f86
("kthread: Ensure struct kthread is present for all kthreads") there
have been no assumptions added that to_kthread or __to_kthread will
not return NULL.
There are a few callers of to_kthread or __to_kthread that assume a
non-NULL struct kthread pointer will be returned. These functions are
kthread_data(), kthread_parmme(), kthread_exit(), kthread(),
kthread_park(), kthread_unpark(), kthread_stop(). All of those functions
can reasonably expected to be called when it is know that a task is a
kthread so that assumption seems reasonable.
Cc: stable@vger.kernel.org
Fixes: 40966e316f86 ("kthread: Ensure struct kthread is present for all kthreads")
Reported-by: Максим Кутявин <maximkabox13@gmail.com>
Link: https://lkml.kernel.org/r/20220506141512.516114-1-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull ptrace cleanups from Eric Biederman:
"This set of changes removes tracehook.h, moves modification of all of
the ptrace fields inside of siglock to remove races, adds a missing
permission check to ptrace.c
The removal of tracehook.h is quite significant as it has been a major
source of confusion in recent years. Much of that confusion was around
task_work and TIF_NOTIFY_SIGNAL (which I have now decoupled making the
semantics clearer).
For people who don't know tracehook.h is a vestiage of an attempt to
implement uprobes like functionality that was never fully merged, and
was later superseeded by uprobes when uprobes was merged. For many
years now we have been removing what tracehook functionaly a little
bit at a time. To the point where anything left in tracehook.h was
some weird strange thing that was difficult to understand"
* tag 'ptrace-cleanups-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
ptrace: Remove duplicated include in ptrace.c
ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZE
ptrace: Return the signal to continue with from ptrace_stop
ptrace: Move setting/clearing ptrace_message into ptrace_stop
tracehook: Remove tracehook.h
resume_user_mode: Move to resume_user_mode.h
resume_user_mode: Remove #ifdef TIF_NOTIFY_RESUME in set_notify_resume
signal: Move set_notify_signal and clear_notify_signal into sched/signal.h
task_work: Decouple TIF_NOTIFY_SIGNAL and task_work
task_work: Call tracehook_notify_signal from get_signal on all architectures
task_work: Introduce task_work_pending
task_work: Remove unnecessary include from posix_timers.h
ptrace: Remove tracehook_signal_handler
ptrace: Remove arch_syscall_{enter,exit}_tracehook
ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h
ptrace/arm: Rename tracehook_report_syscall report_syscall
ptrace: Move ptrace_report_syscall into ptrace.h
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic
Pull asm-generic updates from Arnd Bergmann:
"There are three sets of updates for 5.18 in the asm-generic tree:
- The set_fs()/get_fs() infrastructure gets removed for good.
This was already gone from all major architectures, but now we can
finally remove it everywhere, which loses some particularly tricky
and error-prone code. There is a small merge conflict against a
parisc cleanup, the solution is to use their new version.
- The nds32 architecture ends its tenure in the Linux kernel.
The hardware is still used and the code is in reasonable shape, but
the mainline port is not actively maintained any more, as all
remaining users are thought to run vendor kernels that would never
be updated to a future release.
- A series from Masahiro Yamada cleans up some of the uapi header
files to pass the compile-time checks"
* tag 'asm-generic-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: (27 commits)
nds32: Remove the architecture
uaccess: remove CONFIG_SET_FS
ia64: remove CONFIG_SET_FS support
sh: remove CONFIG_SET_FS support
sparc64: remove CONFIG_SET_FS support
lib/test_lockup: fix kernel pointer check for separate address spaces
uaccess: generalize access_ok()
uaccess: fix type mismatch warnings from access_ok()
arm64: simplify access_ok()
m68k: fix access_ok for coldfire
MIPS: use simpler access_ok()
MIPS: Handle address errors for accesses above CPU max virtual user address
uaccess: add generic __{get,put}_kernel_nofault
nios2: drop access_ok() check from __put_user()
x86: use more conventional access_ok() definition
x86: remove __range_not_ok()
sparc64: add __{get,put}_kernel_nofault()
nds32: fix access_ok() checks in get/put_user
uaccess: fix nios2 and microblaze get_user_8()
sparc64: fix building assembly files
...
|
|
Now that all of the definitions have moved out of tracehook.h into
ptrace.h, sched/signal.h, resume_user_mode.h there is nothing left in
tracehook.h so remove it.
Update the few files that were depending upon tracehook.h to bring in
definitions to use the headers they need directly.
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20220309162454.123006-13-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Remove the second 'from'.
Replace 'backwords' with 'backwards'.
Replace 'visibile' with 'visible'.
Signed-off-by: Tom Rix <trix@redhat.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220211160940.2516243-1-trix@redhat.com
|
|
Quoting[1] Ariadne Conill:
"In several other operating systems, it is a hard requirement that the
second argument to execve(2) be the name of a program, thus prohibiting
a scenario where argc < 1. POSIX 2017 also recommends this behaviour,
but it is not an explicit requirement[2]:
The argument arg0 should point to a filename string that is
associated with the process being started by one of the exec
functions.
...
Interestingly, Michael Kerrisk opened an issue about this in 2008[3],
but there was no consensus to support fixing this issue then.
Hopefully now that CVE-2021-4034 shows practical exploitative use[4]
of this bug in a shellcode, we can reconsider.
This issue is being tracked in the KSPP issue tracker[5]."
While the initial code searches[6][7] turned up what appeared to be
mostly corner case tests, trying to that just reject argv == NULL
(or an immediately terminated pointer list) quickly started tripping[8]
existing userspace programs.
The next best approach is forcing a single empty string into argv and
adjusting argc to match. The number of programs depending on argc == 0
seems a smaller set than those calling execve with a NULL argv.
Account for the additional stack space in bprm_stack_limits(). Inject an
empty string when argc == 0 (and set argc = 1). Warn about the case so
userspace has some notice about the change:
process './argc0' launched './argc0' with NULL argv: empty string added
Additionally WARN() and reject NULL argv usage for kernel threads.
[1] https://lore.kernel.org/lkml/20220127000724.15106-1-ariadne@dereferenced.org/
[2] https://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html
[3] https://bugzilla.kernel.org/show_bug.cgi?id=8408
[4] https://www.qualys.com/2022/01/25/cve-2021-4034/pwnkit.txt
[5] https://github.com/KSPP/linux/issues/176
[6] https://codesearch.debian.net/search?q=execve%5C+*%5C%28%5B%5E%2C%5D%2B%2C+*NULL&literal=0
[7] https://codesearch.debian.net/search?q=execlp%3F%5Cs*%5C%28%5B%5E%2C%5D%2B%2C%5Cs*NULL&literal=0
[8] https://lore.kernel.org/lkml/20220131144352.GE16385@xsang-OptiPlex-9020/
Reported-by: Ariadne Conill <ariadne@dereferenced.org>
Reported-by: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Ariadne Conill <ariadne@dereferenced.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220201000947.2453721-1-keescook@chromium.org
|
|
There are no remaining callers of set_fs(), so CONFIG_SET_FS
can be removed globally, along with the thread_info field and
any references to it.
This turns access_ok() into a cheaper check against TASK_SIZE_MAX.
As CONFIG_SET_FS is now gone, drop all remaining references to
set_fs()/get_fs(), mm_segment_t, user_addr_max() and uaccess_kernel().
Acked-by: Sam Ravnborg <sam@ravnborg.org> # for sparc32 changes
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Tested-by: Sergey Matyukevich <sergey.matyukevich@synopsys.com> # for arc changes
Acked-by: Stafford Horne <shorne@gmail.com> # [openrisc, asm-generic]
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
|
|
This moves the fs/coredump.c respective sysctls to its own file.
Link: https://lkml.kernel.org/r/20211129211943.640266-6-mcgrof@kernel.org
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Stephen Kitt <steve@sk2.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
kernel/sysctl.c is a kitchen sink where everyone leaves their dirty
dishes, this makes it very difficult to maintain.
To help with this maintenance let's start by moving sysctls to places
where they actually belong. The proc sysctl maintainers do not want to
know what sysctl knobs you wish to add for your own piece of code, we
just care about the core logic.
So move the fs/exec.c respective sysctls to its own file.
Since checkpatch complains about style issues with the old code, this
move also fixes a few of those minor style issues:
* Use pr_warn() instead of prink(WARNING
* New empty lines are wanted at the beginning of routines
Link: https://lkml.kernel.org/r/20211129205548.605569-9-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Merge more updates from Andrew Morton:
"55 patches.
Subsystems affected by this patch series: percpu, procfs, sysctl,
misc, core-kernel, get_maintainer, lib, checkpatch, binfmt, nilfs2,
hfs, fat, adfs, panic, delayacct, kconfig, kcov, and ubsan"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (55 commits)
lib: remove redundant assignment to variable ret
ubsan: remove CONFIG_UBSAN_OBJECT_SIZE
kcov: fix generic Kconfig dependencies if ARCH_WANTS_NO_INSTR
lib/Kconfig.debug: make TEST_KMOD depend on PAGE_SIZE_LESS_THAN_256KB
btrfs: use generic Kconfig option for 256kB page size limit
arch/Kconfig: split PAGE_SIZE_LESS_THAN_256KB from PAGE_SIZE_LESS_THAN_64KB
configs: introduce debug.config for CI-like setup
delayacct: track delays from memory compact
Documentation/accounting/delay-accounting.rst: add thrashing page cache and direct compact
delayacct: cleanup flags in struct task_delay_info and functions use it
delayacct: fix incomplete disable operation when switch enable to disable
delayacct: support swapin delay accounting for swapping without blkio
panic: remove oops_id
panic: use error_report_end tracepoint on warnings
fs/adfs: remove unneeded variable make code cleaner
FAT: use io_schedule_timeout() instead of congestion_wait()
hfsplus: use struct_group_attr() for memcpy() region
nilfs2: remove redundant pointer sbufs
fs/binfmt_elf: use PT_LOAD p_align values for static PIE
const_structs.checkpatch: add frequently used ops structs
...
|
|
If the dest buffer size is smaller than sizeof(tsk->comm), the buffer
will be without null ternimator, that may cause problem. Using
strscpy_pad() instead of strncpy() in __get_task_comm() can make the
string always nul ternimated and zero padded.
Link: https://lkml.kernel.org/r/20211120112738.45980-3-laoar.shao@gmail.com
Suggested-by: Kees Cook <keescook@chromium.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "task comm cleanups", v2.
This patchset is part of the patchset "extend task comm from 16 to
24"[1]. Now we have different opinion that dynamically allocates memory
to store kthread's long name into a separate pointer, so I decide to
take the useful cleanups apart from the original patchset and send it
separately[2].
These useful cleanups can make the usage around task comm less
error-prone. Furthermore, it will be useful if we want to extend task
comm in the future.
[1]. https://lore.kernel.org/lkml/20211101060419.4682-1-laoar.shao@gmail.com/
[2]. https://lore.kernel.org/lkml/CALOAHbAx55AUo3bm8ZepZSZnw7A08cvKPdPyNTf=E_tPqmw5hw@mail.gmail.com/
This patch (of 7):
strlcpy() can trigger out-of-bound reads on the source string[1], we'd
better use strscpy() instead. To make it be robust against full tsk->comm
copies that got noticed in other places, we should make sure it's zero
padded.
[1] https://github.com/KSPP/linux/issues/89
Link: https://lkml.kernel.org/r/20211120112738.45980-1-laoar.shao@gmail.com
Link: https://lkml.kernel.org/r/20211120112738.45980-2-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
This helper is misleading. It tests for an ongoing exec as well as
the process having received a fatal signal.
Sometimes it is appropriate to treat an on-going exec differently than
a process that is shutting down due to a fatal signal. In particular
taking the fast path out of exit_signals instead of retargeting
signals is not appropriate during exec, and not changing the the exit
code in do_group_exit during exec.
Removing the helper makes it more obvious what is going on as both
cases must be coded for explicitly.
While removing the helper fix the two cases where I have observed
using signal_group_exit resulted in the wrong result.
In exit_signals only test for SIGNAL_GROUP_EXIT so that signals are
retargetted during an exec.
In do_group_exit use 0 as the exit code during an exec as de_thread
does not set group_exit_code. As best as I can determine
group_exit_code has been is set to 0 most of the time during
de_thread. During a thread group stop group_exit_code is set to the
stop signal and when the thread group receives SIGCONT group_exit_code
is reset to 0.
Link: https://lkml.kernel.org/r/20211213225350.27481-8-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
The only remaining user of group_exit_task is exec. Rename the field
so that it is clear which part of the code uses it.
Update the comment above the definition of group_exec_task to document
how it is currently used.
Link: https://lkml.kernel.org/r/20211213225350.27481-7-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Today the rules are a bit iffy and arbitrary about which kernel
threads have struct kthread present. Both idle threads and thread
started with create_kthread want struct kthread present so that is
effectively all kernel threads. Make the rule that if PF_KTHREAD
and the task is running then struct kthread is present.
This will allow the kernel thread code to using tsk->exit_code
with different semantics from ordinary processes.
To make ensure that struct kthread is present for all
kernel threads move it's allocation into copy_process.
Add a deallocation of struct kthread in exec for processes
that were kernel threads.
Move the allocation of struct kthread for the initial thread
earlier so that it is not repeated for each additional idle
thread.
Move the initialization of struct kthread into set_kthread_struct
so that the structure is always and reliably initailized.
Clear set_child_tid in free_kthread_struct to ensure the kthread
struct is reliably freed during exec. The function
free_kthread_struct does not need to clear vfork_done during exec as
exec_mm_release called from exec_mmap has already cleared vfork_done.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull exit cleanups from Eric Biederman:
"While looking at some issues related to the exit path in the kernel I
found several instances where the code is not using the existing
abstractions properly.
This set of changes introduces force_fatal_sig a way of sending a
signal and not allowing it to be caught, and corrects the misuse of
the existing abstractions that I found.
A lot of the misuse of the existing abstractions are silly things such
as doing something after calling a no return function, rolling BUG by
hand, doing more work than necessary to terminate a kernel thread, or
calling do_exit(SIGKILL) instead of calling force_sig(SIGKILL).
In the review a deficiency in force_fatal_sig and force_sig_seccomp
where ptrace or sigaction could prevent the delivery of the signal was
found. I have added a change that adds SA_IMMUTABLE to change that
makes it impossible to interrupt the delivery of those signals, and
allows backporting to fix force_sig_seccomp
And Arnd found an issue where a function passed to kthread_run had the
wrong prototype, and after my cleanup was failing to build."
* 'exit-cleanups-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (23 commits)
soc: ti: fix wkup_m3_rproc_boot_thread return type
signal: Add SA_IMMUTABLE to ensure forced siganls do not get changed
signal: Replace force_sigsegv(SIGSEGV) with force_fatal_sig(SIGSEGV)
exit/r8188eu: Replace the macro thread_exit with a simple return 0
exit/rtl8712: Replace the macro thread_exit with a simple return 0
exit/rtl8723bs: Replace the macro thread_exit with a simple return 0
signal/x86: In emulate_vsyscall force a signal instead of calling do_exit
signal/sparc32: In setup_rt_frame and setup_fram use force_fatal_sig
signal/sparc32: Exit with a fatal signal when try_to_clear_window_buffer fails
exit/syscall_user_dispatch: Send ordinary signals on failure
signal: Implement force_fatal_sig
exit/kthread: Have kernel threads return instead of calling do_exit
signal/s390: Use force_sigsegv in default_trap_handler
signal/vm86_32: Properly send SIGSEGV when the vm86 state cannot be saved.
signal/vm86_32: Replace open coded BUG_ON with an actual BUG_ON
signal/sparc: In setup_tsb_params convert open coded BUG into BUG
signal/powerpc: On swapcontext failure force SIGSEGV
signal/sh: Use force_sig(SIGKILL) instead of do_group_exit(SIGKILL)
signal/mips: Update (_save|_restore)_fp_context to fail with -EFAULT
signal/sparc32: Remove unreachable do_exit in do_sparc_fault
...
|
|
Now that force_fatal_sig exists it is unnecessary and a bit confusing
to use force_sigsegv in cases where the simpler force_fatal_sig is
wanted. So change every instance we can to make the code clearer.
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Link: https://lkml.kernel.org/r/877de7jrev.fsf@disp2133
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Prevent exec continuing when a fatal signal is pending by replacing
mmap_read_lock with mmap_read_lock_killable. This is always the right
thing to do as userspace will never observe an exec complete when
there is a fatal signal pending.
With that change it becomes unnecessary to explicitly test for a core
dump in progress. In coredump_wait zap_threads arranges under
mmap_write_lock for all tasks that use a mm to also have SIGKILL
pending, which means mmap_read_lock_killable will always return -EINTR
when old_mm->core_state is present.
Link: https://lkml.kernel.org/r/87fstux27w.fsf@disp2133
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Pull MAP_DENYWRITE removal from David Hildenbrand:
"Remove all in-tree usage of MAP_DENYWRITE from the kernel and remove
VM_DENYWRITE.
There are some (minor) user-visible changes:
- We no longer deny write access to shared libaries loaded via legacy
uselib(); this behavior matches modern user space e.g. dlopen().
- We no longer deny write access to the elf interpreter after exec
completed, treating it just like shared libraries (which it often
is).
- We always deny write access to the file linked via /proc/pid/exe:
sys_prctl(PR_SET_MM_MAP/EXE_FILE) will fail if write access to the
file cannot be denied, and write access to the file will remain
denied until the link is effectivel gone (exec, termination,
sys_prctl(PR_SET_MM_MAP/EXE_FILE)) -- just as if exec'ing the file.
Cross-compiled for a bunch of architectures (alpha, microblaze, i386,
s390x, ...) and verified via ltp that especially the relevant tests
(i.e., creat07 and execve04) continue working as expected"
* tag 'denywrite-for-5.15' of git://github.com/davidhildenbrand/linux:
fs: update documentation of get_write_access() and friends
mm: ignore MAP_DENYWRITE in ksys_mmap_pgoff()
mm: remove VM_DENYWRITE
binfmt: remove in-tree usage of MAP_DENYWRITE
kernel/fork: always deny write access to current MM exe_file
kernel/fork: factor out replacing the current MM exe_file
binfmt: don't use MAP_DENYWRITE when loading shared libraries via uselib()
|
|
Merge misc updates from Andrew Morton:
"173 patches.
Subsystems affected by this series: ia64, ocfs2, block, and mm (debug,
pagecache, gup, swap, shmem, memcg, selftests, pagemap, mremap,
bootmem, sparsemem, vmalloc, kasan, pagealloc, memory-failure,
hugetlb, userfaultfd, vmscan, compaction, mempolicy, memblock,
oom-kill, migration, ksm, percpu, vmstat, and madvise)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (173 commits)
mm/madvise: add MADV_WILLNEED to process_madvise()
mm/vmstat: remove unneeded return value
mm/vmstat: simplify the array size calculation
mm/vmstat: correct some wrong comments
mm/percpu,c: remove obsolete comments of pcpu_chunk_populated()
selftests: vm: add COW time test for KSM pages
selftests: vm: add KSM merging time test
mm: KSM: fix data type
selftests: vm: add KSM merging across nodes test
selftests: vm: add KSM zero page merging test
selftests: vm: add KSM unmerge test
selftests: vm: add KSM merge test
mm/migrate: correct kernel-doc notation
mm: wire up syscall process_mrelease
mm: introduce process_mrelease system call
memblock: make memblock_find_in_range method private
mm/mempolicy.c: use in_task() in mempolicy_slab_node()
mm/mempolicy: unify the create() func for bind/interleave/prefer-many policies
mm/mempolicy: advertise new MPOL_PREFERRED_MANY
mm/hugetlb: add support for mempolicy MPOL_PREFERRED_MANY
...
|
|
find_vma() and variants need protection when used. This patch adds
mmap_assert_lock() calls in the functions.
To make sure the invariant is satisfied, we also need to add a
mmap_read_lock() around the get_user_pages_remote() call in
get_arg_page(). The lock is not strictly necessary because the mm has
been newly created, but the extra cost is limited because the same mutex
was also acquired shortly before in __bprm_mm_init(), so it is hot and
uncontended.
[penguin-kernel@i-love.sakura.ne.jp: TOMOYO needs the same protection which get_arg_page() needs]
Link: https://lkml.kernel.org/r/58bb6bf7-a57e-8a40-e74b-39584b415152@i-love.sakura.ne.jp
Link: https://lkml.kernel.org/r/20210731175341.3458608-1-lrizzo@google.com
Signed-off-by: Luigi Rizzo <lrizzo@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
flush_kernel_dcache_page is a rather confusing interface that implements a
subset of flush_dcache_page by not being able to properly handle page
cache mapped pages.
The only callers left are in the exec code as all other previous callers
were incorrect as they could have dealt with page cache pages. Replace
the calls to flush_kernel_dcache_page with calls to flush_dcache_page,
which for all architectures does either exactly the same thing, can
contains one or more of the following:
1) an optimization to defer the cache flush for page cache pages not
mapped into userspace
2) additional flushing for mapped page cache pages if cache aliases
are possible
Link: https://lkml.kernel.org/r/20210712060928.4161649-7-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Cercueil <paul@crapouillou.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Yoshinori Sato <ysato@users.osdn.me>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
We want to remove VM_DENYWRITE only currently only used when mapping the
executable during exec. During exec, we already deny_write_access() the
executable, however, after exec completes the VMAs mapped
with VM_DENYWRITE effectively keeps write access denied via
deny_write_access().
Let's deny write access when setting or replacing the MM exe_file. With
this change, we can remove VM_DENYWRITE for mapping executables.
Make set_mm_exe_file() return an error in case deny_write_access()
fails; note that this should never happen, because exec code does a
deny_write_access() early and keeps write access denied when calling
set_mm_exe_file. However, it makes the code easier to read and makes
set_mm_exe_file() and replace_mm_exe_file() look more similar.
This represents a minor user space visible change:
sys_prctl(PR_SET_MM_MAP/EXE_FILE) can now fail if the file is already
opened writable. Also, after sys_prctl(PR_SET_MM_MAP/EXE_FILE) the file
cannot be opened writable. Note that we can already fail with -EACCES if
the file doesn't have execute permissions.
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
|
|
There are a couple of places where we already open-code the (flags &
AT_EMPTY_PATH) check and io_uring will likely add another one in the
future. Let's just add a simple helper getname_uflags() that handles
this directly and use it.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/io-uring/20210415100815.edrn4a7cy26wkowe@wittgenstein/
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20210708063447.3556403-7-dkadashev@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
|
Merge more updates from Andrew Morton:
"190 patches.
Subsystems affected by this patch series: mm (hugetlb, userfaultfd,
vmscan, kconfig, proc, z3fold, zbud, ras, mempolicy, memblock,
migration, thp, nommu, kconfig, madvise, memory-hotplug, zswap,
zsmalloc, zram, cleanups, kfence, and hmm), procfs, sysctl, misc,
core-kernel, lib, lz4, checkpatch, init, kprobes, nilfs2, hfs,
signals, exec, kcov, selftests, compress/decompress, and ipc"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (190 commits)
ipc/util.c: use binary search for max_idx
ipc/sem.c: use READ_ONCE()/WRITE_ONCE() for use_global_lock
ipc: use kmalloc for msg_queue and shmid_kernel
ipc sem: use kvmalloc for sem_undo allocation
lib/decompressors: remove set but not used variabled 'level'
selftests/vm/pkeys: exercise x86 XSAVE init state
selftests/vm/pkeys: refill shadow register after implicit kernel write
selftests/vm/pkeys: handle negative sys_pkey_alloc() return code
selftests/vm/pkeys: fix alloc_random_pkey() to make it really, really random
kcov: add __no_sanitize_coverage to fix noinstr for all architectures
exec: remove checks in __register_bimfmt()
x86: signal: don't do sas_ss_reset() until we are certain that sigframe won't be abandoned
hfsplus: report create_date to kstat.btime
hfsplus: remove unnecessary oom message
nilfs2: remove redundant continue statement in a while-loop
kprobes: remove duplicated strong free_insn_page in x86 and s390
init: print out unknown kernel parameters
checkpatch: do not complain about positive return values starting with EPOLL
checkpatch: improve the indented label test
checkpatch: scripts/spdxcheck.py now requires python3
...
|
|
Delete NULL check, all callers pass valid pointer.
Delete ->load_binary check -- failure to provide hook in a custom module
will be very noticeable at the very first execve call.
Link: https://lkml.kernel.org/r/YK1Gy1qXaLAR+tPl@localhost.localdomain
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The rlimit counter is tied to uid in the user_namespace. This allows
rlimit values to be specified in userns even if they are already
globally exceeded by the user. However, the value of the previous
user_namespaces cannot be exceeded.
To illustrate the impact of rlimits, let's say there is a program that
does not fork. Some service-A wants to run this program as user X in
multiple containers. Since the program never fork the service wants to
set RLIMIT_NPROC=1.
service-A
\- program (uid=1000, container1, rlimit_nproc=1)
\- program (uid=1000, container2, rlimit_nproc=1)
The service-A sets RLIMIT_NPROC=1 and runs the program in container1.
When the service-A tries to run a program with RLIMIT_NPROC=1 in
container2 it fails since user X already has one running process.
We cannot use existing inc_ucounts / dec_ucounts because they do not
allow us to exceed the maximum for the counter. Some rlimits can be
overlimited by root or if the user has the appropriate capability.
Changelog
v11:
* Change inc_rlimit_ucounts() which now returns top value of ucounts.
* Drop inc_rlimit_ucounts_and_test() because the return code of
inc_rlimit_ucounts() can be checked.
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Link: https://lkml.kernel.org/r/c5286a8aa16d2d698c222f7532f3d735c82bc6bc.1619094428.git.legion@kernel.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
|
|
For RLIMIT_NPROC and some other rlimits the user_struct that holds the
global limit is kept alive for the lifetime of a process by keeping it
in struct cred. Adding a pointer to ucounts in the struct cred will
allow to track RLIMIT_NPROC not only for user in the system, but for
user in the user_namespace.
Updating ucounts may require memory allocation which may fail. So, we
cannot change cred.ucounts in the commit_creds() because this function
cannot fail and it should always return 0. For this reason, we modify
cred.ucounts before calling the commit_creds().
Changelog
v6:
* Fix null-ptr-deref in is_ucounts_overlimit() detected by trinity. This
error was caused by the fact that cred_alloc_blank() left the ucounts
pointer empty.
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Link: https://lkml.kernel.org/r/b37aaef28d8b9b0d757e07ba6dd27281bbe39259.1619094428.git.legion@kernel.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
|
|
Delete duplicate words in fs/*.c.
The doubled words that are being dropped are:
that, be, the, in, and, for
Link: https://lkml.kernel.org/r/20201224052810.25315-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull idmapped mounts from Christian Brauner:
"This introduces idmapped mounts which has been in the making for some
time. Simply put, different mounts can expose the same file or
directory with different ownership. This initial implementation comes
with ports for fat, ext4 and with Christoph's port for xfs with more
filesystems being actively worked on by independent people and
maintainers.
Idmapping mounts handle a wide range of long standing use-cases. Here
are just a few:
- Idmapped mounts make it possible to easily share files between
multiple users or multiple machines especially in complex
scenarios. For example, idmapped mounts will be used in the
implementation of portable home directories in
systemd-homed.service(8) where they allow users to move their home
directory to an external storage device and use it on multiple
computers where they are assigned different uids and gids. This
effectively makes it possible to assign random uids and gids at
login time.
- It is possible to share files from the host with unprivileged
containers without having to change ownership permanently through
chown(2).
- It is possible to idmap a container's rootfs and without having to
mangle every file. For example, Chromebooks use it to share the
user's Download folder with their unprivileged containers in their
Linux subsystem.
- It is possible to share files between containers with
non-overlapping idmappings.
- Filesystem that lack a proper concept of ownership such as fat can
use idmapped mounts to implement discretionary access (DAC)
permission checking.
- They allow users to efficiently changing ownership on a per-mount
basis without having to (recursively) chown(2) all files. In
contrast to chown (2) changing ownership of large sets of files is
instantenous with idmapped mounts. This is especially useful when
ownership of a whole root filesystem of a virtual machine or
container is changed. With idmapped mounts a single syscall
mount_setattr syscall will be sufficient to change the ownership of
all files.
- Idmapped mounts always take the current ownership into account as
idmappings specify what a given uid or gid is supposed to be mapped
to. This contrasts with the chown(2) syscall which cannot by itself
take the current ownership of the files it changes into account. It
simply changes the ownership to the specified uid and gid. This is
especially problematic when recursively chown(2)ing a large set of
files which is commong with the aforementioned portable home
directory and container and vm scenario.
- Idmapped mounts allow to change ownership locally, restricting it
to specific mounts, and temporarily as the ownership changes only
apply as long as the mount exists.
Several userspace projects have either already put up patches and
pull-requests for this feature or will do so should you decide to pull
this:
- systemd: In a wide variety of scenarios but especially right away
in their implementation of portable home directories.
https://systemd.io/HOME_DIRECTORY/
- container runtimes: containerd, runC, LXD:To share data between
host and unprivileged containers, unprivileged and privileged
containers, etc. The pull request for idmapped mounts support in
containerd, the default Kubernetes runtime is already up for quite
a while now: https://github.com/containerd/containerd/pull/4734
- The virtio-fs developers and several users have expressed interest
in using this feature with virtual machines once virtio-fs is
ported.
- ChromeOS: Sharing host-directories with unprivileged containers.
I've tightly synced with all those projects and all of those listed
here have also expressed their need/desire for this feature on the
mailing list. For more info on how people use this there's a bunch of
talks about this too. Here's just two recent ones:
https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdf
https://fosdem.org/2021/schedule/event/containers_idmap/
This comes with an extensive xfstests suite covering both ext4 and
xfs:
https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts
It covers truncation, creation, opening, xattrs, vfscaps, setid
execution, setgid inheritance and more both with idmapped and
non-idmapped mounts. It already helped to discover an unrelated xfs
setgid inheritance bug which has since been fixed in mainline. It will
be sent for inclusion with the xfstests project should you decide to
merge this.
In order to support per-mount idmappings vfsmounts are marked with
user namespaces. The idmapping of the user namespace will be used to
map the ids of vfs objects when they are accessed through that mount.
By default all vfsmounts are marked with the initial user namespace.
The initial user namespace is used to indicate that a mount is not
idmapped. All operations behave as before and this is verified in the
testsuite.
Based on prior discussions we want to attach the whole user namespace
and not just a dedicated idmapping struct. This allows us to reuse all
the helpers that already exist for dealing with idmappings instead of
introducing a whole new range of helpers. In addition, if we decide in
the future that we are confident enough to enable unprivileged users
to setup idmapped mounts the permission checking can take into account
whether the caller is privileged in the user namespace the mount is
currently marked with.
The user namespace the mount will be marked with can be specified by
passing a file descriptor refering to the user namespace as an
argument to the new mount_setattr() syscall together with the new
MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern
of extensibility.
The following conditions must be met in order to create an idmapped
mount:
- The caller must currently have the CAP_SYS_ADMIN capability in the
user namespace the underlying filesystem has been mounted in.
- The underlying filesystem must support idmapped mounts.
- The mount must not already be idmapped. This also implies that the
idmapping of a mount cannot be altered once it has been idmapped.
- The mount must be a detached/anonymous mount, i.e. it must have
been created by calling open_tree() with the OPEN_TREE_CLONE flag
and it must not already have been visible in the filesystem.
The last two points guarantee easier semantics for userspace and the
kernel and make the implementation significantly simpler.
By default vfsmounts are marked with the initial user namespace and no
behavioral or performance changes are observed.
The manpage with a detailed description can be found here:
https://git.kernel.org/brauner/man-pages/c/1d7b902e2875a1ff342e036a9f866a995640aea8
In order to support idmapped mounts, filesystems need to be changed
and mark themselves with the FS_ALLOW_IDMAP flag in fs_flags. The
patches to convert individual filesystem are not very large or
complicated overall as can be seen from the included fat, ext4, and
xfs ports. Patches for other filesystems are actively worked on and
will be sent out separately. The xfstestsuite can be used to verify
that port has been done correctly.
The mount_setattr() syscall is motivated independent of the idmapped
mounts patches and it's been around since July 2019. One of the most
valuable features of the new mount api is the ability to perform
mounts based on file descriptors only.
Together with the lookup restrictions available in the openat2()
RESOLVE_* flag namespace which we added in v5.6 this is the first time
we are close to hardened and race-free (e.g. symlinks) mounting and
path resolution.
While userspace has started porting to the new mount api to mount
proper filesystems and create new bind-mounts it is currently not
possible to change mount options of an already existing bind mount in
the new mount api since the mount_setattr() syscall is missing.
With the addition of the mount_setattr() syscall we remove this last
restriction and userspace can now fully port to the new mount api,
covering every use-case the old mount api could. We also add the
crucial ability to recursively change mount options for a whole mount
tree, both removing and adding mount options at the same time. This
syscall has been requested multiple times by various people and
projects.
There is a simple tool available at
https://github.com/brauner/mount-idmapped
that allows to create idmapped mounts so people can play with this
patch series. I'll add support for the regular mount binary should you
decide to pull this in the following weeks:
Here's an example to a simple idmapped mount of another user's home
directory:
u1001@f2-vm:/$ sudo ./mount --idmap both:1000:1001:1 /home/ubuntu/ /mnt
u1001@f2-vm:/$ ls -al /home/ubuntu/
total 28
drwxr-xr-x 2 ubuntu ubuntu 4096 Oct 28 22:07 .
drwxr-xr-x 4 root root 4096 Oct 28 04:00 ..
-rw------- 1 ubuntu ubuntu 3154 Oct 28 22:12 .bash_history
-rw-r--r-- 1 ubuntu ubuntu 220 Feb 25 2020 .bash_logout
-rw-r--r-- 1 ubuntu ubuntu 3771 Feb 25 2020 .bashrc
-rw-r--r-- 1 ubuntu ubuntu 807 Feb 25 2020 .profile
-rw-r--r-- 1 ubuntu ubuntu 0 Oct 16 16:11 .sudo_as_admin_successful
-rw------- 1 ubuntu ubuntu 1144 Oct 28 00:43 .viminfo
u1001@f2-vm:/$ ls -al /mnt/
total 28
drwxr-xr-x 2 u1001 u1001 4096 Oct 28 22:07 .
drwxr-xr-x 29 root root 4096 Oct 28 22:01 ..
-rw------- 1 u1001 u1001 3154 Oct 28 22:12 .bash_history
-rw-r--r-- 1 u1001 u1001 220 Feb 25 2020 .bash_logout
-rw-r--r-- 1 u1001 u1001 3771 Feb 25 2020 .bashrc
-rw-r--r-- 1 u1001 u1001 807 Feb 25 2020 .profile
-rw-r--r-- 1 u1001 u1001 0 Oct 16 16:11 .sudo_as_admin_successful
-rw------- 1 u1001 u1001 1144 Oct 28 00:43 .viminfo
u1001@f2-vm:/$ touch /mnt/my-file
u1001@f2-vm:/$ setfacl -m u:1001:rwx /mnt/my-file
u1001@f2-vm:/$ sudo setcap -n 1001 cap_net_raw+ep /mnt/my-file
u1001@f2-vm:/$ ls -al /mnt/my-file
-rw-rwxr--+ 1 u1001 u1001 0 Oct 28 22:14 /mnt/my-file
u1001@f2-vm:/$ ls -al /home/ubuntu/my-file
-rw-rwxr--+ 1 ubuntu ubuntu 0 Oct 28 22:14 /home/ubuntu/my-file
u1001@f2-vm:/$ getfacl /mnt/my-file
getfacl: Removing leading '/' from absolute path names
# file: mnt/my-file
# owner: u1001
# group: u1001
user::rw-
user:u1001:rwx
group::rw-
mask::rwx
other::r--
u1001@f2-vm:/$ getfacl /home/ubuntu/my-file
getfacl: Removing leading '/' from absolute path names
# file: home/ubuntu/my-file
# owner: ubuntu
# group: ubuntu
user::rw-
user:ubuntu:rwx
group::rw-
mask::rwx
other::r--"
* tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: (41 commits)
xfs: remove the possibly unused mp variable in xfs_file_compat_ioctl
xfs: support idmapped mounts
ext4: support idmapped mounts
fat: handle idmapped mounts
tests: add mount_setattr() selftests
fs: introduce MOUNT_ATTR_IDMAP
fs: add mount_setattr()
fs: add attr_flags_to_mnt_flags helper
fs: split out functions to hold writers
namespace: only take read lock in do_reconfigure_mnt()
mount: make {lock,unlock}_mount_hash() static
namespace: take lock_mount_hash() directly when changing flags
nfs: do not export idmapped mounts
overlayfs: do not mount on top of idmapped mounts
ecryptfs: do not mount on top of idmapped mounts
ima: handle idmapped mounts
apparmor: handle idmapped mounts
fs: make helpers idmap mount aware
exec: handle idmapped mounts
would_dump: handle idmapped mounts
...
|
|
The 'start' and 'end' arguments to tlb_gather_mmu() are no longer
needed now that there is a separate function for 'fullmm' flushing.
Remove the unused arguments and update all callers.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Yu Zhao <yuzhao@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/CAHk-=wjQWa14_4UpfDf=fiineNP+RH74kZeDMo_f1D35xNzq9w@mail.gmail.com
|
|
Since commit 7a30df49f63a ("mm: mmu_gather: remove __tlb_reset_range()
for force flush"), the 'start' and 'end' arguments to tlb_finish_mmu()
are no longer used, since we flush the whole mm in case of a nested
invalidation.
Remove the unused arguments and update all callers.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Yu Zhao <yuzhao@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lkml.kernel.org/r/20210127235347.1402-3-will@kernel.org
|
|
When executing a setuid binary the kernel will verify in bprm_fill_uid()
that the inode has a mapping in the caller's user namespace before
setting the callers uid and gid. Let bprm_fill_uid() handle idmapped
mounts. If the inode is accessed through an idmapped mount it is mapped
according to the mount's user namespace. Afterwards the checks are
identical to non-idmapped mounts. If the initial user namespace is
passed nothing changes so non-idmapped mounts will see identical
behavior as before.
Link: https://lore.kernel.org/r/20210121131959.646623-24-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
|
|
When determining whether or not to create a coredump the vfs will verify
that the caller is privileged over the inode. Make the would_dump()
helper handle idmapped mounts by passing down the mount's user namespace
of the exec file. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.
Link: https://lore.kernel.org/r/20210121131959.646623-23-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
|
|
The two helpers inode_permission() and generic_permission() are used by
the vfs to perform basic permission checking by verifying that the
caller is privileged over an inode. In order to handle idmapped mounts
we extend the two helpers with an additional user namespace argument.
On idmapped mounts the two helpers will make sure to map the inode
according to the mount's user namespace and then peform identical
permission checks to inode_permission() and generic_permission(). If the
initial user namespace is passed nothing changes so non-idmapped mounts
will see identical behavior as before.
Link: https://lore.kernel.org/r/20210121131959.646623-6-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
|
|
In order to determine whether a caller holds privilege over a given
inode the capability framework exposes the two helpers
privileged_wrt_inode_uidgid() and capable_wrt_inode_uidgid(). The former
verifies that the inode has a mapping in the caller's user namespace and
the latter additionally verifies that the caller has the requested
capability in their current user namespace.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped inodes. If the initial user namespace is passed all
operations are a nop so non-idmapped mounts will not see a change in
behavior.
Link: https://lore.kernel.org/r/20210121131959.646623-5-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
Pull parisc updates from Helge Deller:
"A change to increase the default maximum stack size on parisc to 100MB
and the ability to further increase the stack hard limit size at
runtime with ulimit for newly started processes.
The other patches fix compile warnings, utilize the Kbuild logic and
cleanups the parisc arch code"
* 'parisc-5.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
parisc: pci-dma: fix warning unused-function
parisc/uapi: Use Kbuild logic to provide <asm/types.h>
parisc: Make user stack size configurable
parisc: Use _TIF_USER_WORK_MASK in entry.S
parisc: Drop loops_per_jiffy from per_cpu struct
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull exec-update-lock update from Eric Biederman:
"The key point of this is to transform exec_update_mutex into a
rw_semaphore so readers can be separated from writers.
This makes it easier to understand what the holders of the lock are
doing, and makes it harder to contend or deadlock on the lock.
The real deadlock fix wound up in perf_event_open"
* 'exec-update-lock-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
exec: Transform exec_update_mutex into a rw_semaphore
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull execve updates from Eric Biederman:
"This set of changes ultimately fixes the interaction of posix file
lock and exec. Fundamentally most of the change is just moving where
unshare_files is called during exec, and tweaking the users of
files_struct so that the count of files_struct is not unnecessarily
played with.
Along the way fcheck and related helpers were renamed to more
accurately reflect what they do.
There were also many other small changes that fell out, as this is the
first time in a long time much of this code has been touched.
Benchmarks haven't turned up any practical issues but Al Viro has
observed a possibility for a lot of pounding on task_lock. So I have
some changes in progress to convert put_files_struct to always rcu
free files_struct. That wasn't ready for the merge window so that will
have to wait until next time"
* 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits)
exec: Move io_uring_task_cancel after the point of no return
coredump: Document coredump code exclusively used by cell spufs
file: Remove get_files_struct
file: Rename __close_fd_get_file close_fd_get_file
file: Replace ksys_close with close_fd
file: Rename __close_fd to close_fd and remove the files parameter
file: Merge __alloc_fd into alloc_fd
file: In f_dupfd read RLIMIT_NOFILE once.
file: Merge __fd_install into fd_install
proc/fd: In fdinfo seq_show don't use get_files_struct
bpf/task_iter: In task_file_seq_get_next use task_lookup_next_fd_rcu
proc/fd: In proc_readfd_common use task_lookup_next_fd_rcu
file: Implement task_lookup_next_fd_rcu
kcmp: In get_file_raw_ptr use task_lookup_fd_rcu
proc/fd: In tid_fd_mode use task_lookup_fd_rcu
file: Implement task_lookup_fd_rcu
file: Rename fcheck lookup_fd_rcu
file: Replace fcheck_files with files_lookup_fd_rcu
file: Factor files_lookup_fd_locked out of fcheck_files
file: Rename __fcheck_files to files_lookup_fd_raw
...
|
|
Recently syzbot reported[0] that there is a deadlock amongst the users
of exec_update_mutex. The problematic lock ordering found by lockdep
was:
perf_event_open (exec_update_mutex -> ovl_i_mutex)
chown (ovl_i_mutex -> sb_writes)
sendfile (sb_writes -> p->lock)
by reading from a proc file and writing to overlayfs
proc_pid_syscall (p->lock -> exec_update_mutex)
While looking at possible solutions it occured to me that all of the
users and possible users involved only wanted to state of the given
process to remain the same. They are all readers. The only writer is
exec.
There is no reason for readers to block on each other. So fix
this deadlock by transforming exec_update_mutex into a rw_semaphore
named exec_update_lock that only exec takes for writing.
Cc: Jann Horn <jannh@google.com>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Bernd Edlinger <bernd.edlinger@hotmail.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christopher Yeoh <cyeoh@au1.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Sargun Dhillon <sargun@sargun.me>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Fixes: eea9673250db ("exec: Add exec_update_mutex to replace cred_guard_mutex")
[0] https://lkml.kernel.org/r/00000000000063640c05ade8e3de@google.com
Reported-by: syzbot+db9cdf3dd1f64252c6ef@syzkaller.appspotmail.com
Link: https://lkml.kernel.org/r/87ft4mbqen.fsf@x220.int.ebiederm.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
|
|
Now that unshare_files happens in begin_new_exec after the point of no
return, io_uring_task_cancel can also happen later.
Effectively this means io_uring activities for a task are only canceled
when exec succeeds.
Link: https://lkml.kernel.org/r/878saih2op.fsf@x220.int.ebiederm.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
|
|
Now that exec no longer needs to return the unshared files to their
previous value there is no reason to return displaced.
Instead when unshare_fd creates a copy of the file table, call
put_files_struct before returning from unshare_files.
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
v1: https://lkml.kernel.org/r/20200817220425.9389-2-ebiederm@xmission.com
Link: https://lkml.kernel.org/r/20201120231441.29911-2-ebiederm@xmission.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
|
|
Many moons ago the binfmts were doing some very questionable things
with file descriptors and an unsharing of the file descriptor table
was added to make things better[1][2]. The helper steal_lockss was
added to avoid breaking the userspace programs[3][4][6].
Unfortunately it turned out that steal_locks did not work for network
file systems[5], so it was removed to see if anyone would
complain[7][8]. It was thought at the time that NPTL would not be
affected as the unshare_files happened after the other threads were
killed[8]. Unfortunately because there was an unshare_files in
binfmt_elf.c before the threads were killed this analysis was
incorrect.
This unshare_files in binfmt_elf.c resulted in the unshares_files
happening whenever threads were present. Which led to unshare_files
being moved to the start of do_execve[9].
Later the problems were rediscovered and the suggested approach was to
readd steal_locks under a different name[10]. I happened to be
reviewing patches and I noticed that this approach was a step
backwards[11].
I proposed simply moving unshare_files[12] and it was pointed
out that moving unshare_files without auditing the code was
also unsafe[13].
There were then several attempts to solve this[14][15][16] and I even
posted this set of changes[17]. Unfortunately because auditing all of
execve is time consuming this change did not make it in at the time.
Well now that I am cleaning up exec I have made the time to read
through all of the binfmts and the only playing with file descriptors
is either the security modules closing them in
security_bprm_committing_creds or is in the generic code in fs/exec.c.
None of it happens before begin_new_exec is called.
So move unshare_files into begin_new_exec, after the point of no
return. If memory is very very very low and the application calling
exec is sharing file descriptor tables between processes we might fail
past the point of no return. Which is unfortunate but no different
than any of the other places where we allocate memory after the point
of no return.
This movement allows another process that shares the file table, or
another thread of the same process and that closes files or changes
their close on exec behavior and races with execve to cause some
unexpected things to happen. There is only one time of check to time
of use race and it is just there so that execve fails instead of
an interpreter failing when it tries to open the file it is supposed
to be interpreting. Failing later if userspace is being silly is
not a problem.
With this change it the following discription from the removal
of steal_locks[8] finally becomes true.
Apps using NPTL are not affected, since all other threads are killed before
execve.
Apps using LinuxThreads are only affected if they
- have multiple threads during exec (LinuxThreads doesn't kill other
threads, the app may do it with pthread_kill_other_threads_np())
- rely on POSIX locks being inherited across exec
Both conditions are documented, but not their interaction.
Apps using clone() natively are affected if they
- use clone(CLONE_FILES)
- rely on POSIX locks being inherited across exec
I have investigated some paths to make it possible to solve this
without moving unshare_files but they all look more complicated[18].
Reported-by: Daniel P. Berrangé <berrange@redhat.com>
Reported-by: Jeff Layton <jlayton@redhat.com>
History-tree: git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
[1] 02cda956de0b ("[PATCH] unshare_files"
[2] 04e9bcb4d106 ("[PATCH] use new unshare_files helper")
[3] 088f5d7244de ("[PATCH] add steal_locks helper")
[4] 02c541ec8ffa ("[PATCH] use new steal_locks helper")
[5] https://lkml.kernel.org/r/E1FLIlF-0007zR-00@dorka.pomaz.szeredi.hu
[6] https://lkml.kernel.org/r/0060321191605.GB15997@sorel.sous-sol.org
[7] https://lkml.kernel.org/r/E1FLwjC-0000kJ-00@dorka.pomaz.szeredi.hu
[8] c89681ed7d0e ("[PATCH] remove steal_locks()")
[9] fd8328be874f ("[PATCH] sanitize handling of shared descriptor tables in failing execve()")
[10] https://lkml.kernel.org/r/20180317142520.30520-1-jlayton@kernel.org
[11] https://lkml.kernel.org/r/87r2nwqk73.fsf@xmission.com
[12] https://lkml.kernel.org/r/87bmfgvg8w.fsf@xmission.com
[13] https://lkml.kernel.org/r/20180322111424.GE30522@ZenIV.linux.org.uk
[14] https://lkml.kernel.org/r/20180827174722.3723-1-jlayton@kernel.org
[15] https://lkml.kernel.org/r/20180830172423.21964-1-jlayton@kernel.org
[16] https://lkml.kernel.org/r/20180914105310.6454-1-jlayton@kernel.org
[17] https://lkml.kernel.org/r/87a7ohs5ow.fsf@xmission.com
[18] https://lkml.kernel.org/r/87pn8c1uj6.fsf_-_@x220.int.ebiederm.org
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
v1: https://lkml.kernel.org/r/20200817220425.9389-1-ebiederm@xmission.com
Link: https://lkml.kernel.org/r/20201120231441.29911-1-ebiederm@xmission.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
|
|
Al Viro pointed out that using the phrase "close_on_exec(fd,
rcu_dereference_raw(current->files->fdt))" instead of wrapping it in
rcu_read_lock(), rcu_read_unlock() is a very questionable
optimization[1].
Once wrapped with rcu_read_lock()/rcu_read_unlock() that phrase
becomes equivalent the helper function get_close_on_exec so
simplify the code and make it more robust by simply using
get_close_on_exec.
[1] https://lkml.kernel.org/r/20201207222214.GA4115853@ZenIV.linux.org.uk
Suggested-by: Al Viro <viro@ftp.linux.org.uk>
Link: https://lkml.kernel.org/r/87k0tqr6zi.fsf_-_@x220.int.ebiederm.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
|
|
Introduce a mechanism to quickly disable/enable syscall handling for a
specific process and redirect to userspace via SIGSYS. This is useful
for processes with parts that require syscall redirection and parts that
don't, but who need to perform this boundary crossing really fast,
without paying the cost of a system call to reconfigure syscall handling
on each boundary transition. This is particularly important for Windows
games running over Wine.
The proposed interface looks like this:
prctl(PR_SET_SYSCALL_USER_DISPATCH, <op>, <off>, <length>, [selector])
The range [<offset>,<offset>+<length>) is a part of the process memory
map that is allowed to by-pass the redirection code and dispatch
syscalls directly, such that in fast paths a process doesn't need to
disable the trap nor the kernel has to check the selector. This is
essential to return from SIGSYS to a blocked area without triggering
another SIGSYS from rt_sigreturn.
selector is an optional pointer to a char-sized userspace memory region
that has a key switch for the mechanism. This key switch is set to
either PR_SYS_DISPATCH_ON, PR_SYS_DISPATCH_OFF to enable and disable the
redirection without calling the kernel.
The feature is meant to be set per-thread and it is disabled on
fork/clone/execv.
Internally, this doesn't add overhead to the syscall hot path, and it
requires very little per-architecture support. I avoided using seccomp,
even though it duplicates some functionality, due to previous feedback
that maybe it shouldn't mix with seccomp since it is not a security
mechanism. And obviously, this should never be considered a security
mechanism, since any part of the program can by-pass it by using the
syscall dispatcher.
For the sysinfo benchmark, which measures the overhead added to
executing a native syscall that doesn't require interception, the
overhead using only the direct dispatcher region to issue syscalls is
pretty much irrelevant. The overhead of using the selector goes around
40ns for a native (unredirected) syscall in my system, and it is (as
expected) dominated by the supervisor-mode user-address access. In
fact, with SMAP off, the overhead is consistently less than 5ns on my
test box.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201127193238.821364-4-krisman@collabora.com
|
|
On parisc we need to initialize the memory layout for the user stack at
process start time to a fixed size, which up until now was limited to
the size as given by CONFIG_MAX_STACK_SIZE_MB at compile time.
This hard limit was too small and showed problems when compiling
ruby2.7, qmlcachegen and some Qt packages.
This patch changes two things:
a) It increases the default maximum stack size to 100MB.
b) Users can modify the stack hard limit size with ulimit and then newly
forked processes will use the given stack size which can even be bigger
than the default 100MB.
Reported-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
- A series from Nick adding ARCH_WANT_IRQS_OFF_ACTIVATE_MM & selecting
it for powerpc, as well as a related fix for sparc.
- Remove support for PowerPC 601.
- Some fixes for watchpoints & addition of a new ptrace flag for
detecting ISA v3.1 (Power10) watchpoint features.
- A fix for kernels using 4K pages and the hash MMU on bare metal
Power9 systems with > 16TB of RAM, or RAM on the 2nd node.
- A basic idle driver for shallow stop states on Power10.
- Tweaks to our sched domains code to better inform the scheduler about
the hardware topology on Power9/10, where two SMT4 cores can be
presented by firmware as an SMT8 core.
- A series doing further reworks & cleanups of our EEH code.
- Addition of a filter for RTAS (firmware) calls done via sys_rtas(),
to prevent root from overwriting kernel memory.
- Other smaller features, fixes & cleanups.
Thanks to: Alexey Kardashevskiy, Andrew Donnellan, Aneesh Kumar K.V,
Athira Rajeev, Biwen Li, Cameron Berkenpas, Cédric Le Goater, Christophe
Leroy, Christoph Hellwig, Colin Ian King, Daniel Axtens, David Dai, Finn
Thain, Frederic Barrat, Gautham R. Shenoy, Greg Kurz, Gustavo Romero,
Ira Weiny, Jason Yan, Joel Stanley, Jordan Niethe, Kajol Jain, Konrad
Rzeszutek Wilk, Laurent Dufour, Leonardo Bras, Liu Shixin, Luca
Ceresoli, Madhavan Srinivasan, Mahesh Salgaonkar, Nathan Lynch, Nicholas
Mc Guire, Nicholas Piggin, Nick Desaulniers, Oliver O'Halloran, Pedro
Miraglia Franco de Carvalho, Pratik Rajesh Sampat, Qian Cai, Qinglang
Miao, Ravi Bangoria, Russell Currey, Satheesh Rajendran, Scott Cheloha,
Segher Boessenkool, Srikar Dronamraju, Stan Johnson, Stephen Kitt,
Stephen Rothwell, Thiago Jung Bauermann, Tyrel Datwyler, Vaibhav Jain,
Vaidyanathan Srinivasan, Vasant Hegde, Wang Wensheng, Wolfram Sang, Yang
Yingliang, zhengbin.
* tag 'powerpc-5.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (228 commits)
Revert "powerpc/pci: unmap legacy INTx interrupts when a PHB is removed"
selftests/powerpc: Fix eeh-basic.sh exit codes
cpufreq: powernv: Fix frame-size-overflow in powernv_cpufreq_reboot_notifier
powerpc/time: Make get_tb() common to PPC32 and PPC64
powerpc/time: Make get_tbl() common to PPC32 and PPC64
powerpc/time: Remove get_tbu()
powerpc/time: Avoid using get_tbl() and get_tbu() internally
powerpc/time: Make mftb() common to PPC32 and PPC64
powerpc/time: Rename mftbl() to mftb()
powerpc/32s: Remove #ifdef CONFIG_PPC_BOOK3S_32 in head_book3s_32.S
powerpc/32s: Rename head_32.S to head_book3s_32.S
powerpc/32s: Setup the early hash table at all time.
powerpc/time: Remove ifdef in get_dec() and set_dec()
powerpc: Remove get_tb_or_rtc()
powerpc: Remove __USE_RTC()
powerpc: Tidy up a bit after removal of PowerPC 601.
powerpc: Remove support for PowerPC 601
powerpc: Remove PowerPC 601
powerpc: Drop SYNC_601() ISYNC_601() and SYNC()
powerpc: Remove CONFIG_PPC601_SYNC_FIX
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc driver updates from Greg KH:
"Here is the big set of char, misc, and other assorted driver subsystem
patches for 5.10-rc1.
There's a lot of different things in here, all over the drivers/
directory. Some summaries:
- soundwire driver updates
- habanalabs driver updates
- extcon driver updates
- nitro_enclaves new driver
- fsl-mc driver and core updates
- mhi core and bus updates
- nvmem driver updates
- eeprom driver updates
- binder driver updates and fixes
- vbox minor bugfixes
- fsi driver updates
- w1 driver updates
- coresight driver updates
- interconnect driver updates
- misc driver updates
- other minor driver updates
All of these have been in linux-next for a while with no reported
issues"
* tag 'char-misc-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (396 commits)
binder: fix UAF when releasing todo list
docs: w1: w1_therm: Fix broken xref, mistakes, clarify text
misc: Kconfig: fix a HISI_HIKEY_USB dependency
LSM: Fix type of id parameter in kernel_post_load_data prototype
misc: Kconfig: add a new dependency for HISI_HIKEY_USB
firmware_loader: fix a kernel-doc markup
w1: w1_therm: make w1_poll_completion static
binder: simplify the return expression of binder_mmap
test_firmware: Test partial read support
firmware: Add request_partial_firmware_into_buf()
firmware: Store opt_flags in fw_priv
fs/kernel_file_read: Add "offset" arg for partial reads
IMA: Add support for file reads without contents
LSM: Add "contents" flag to kernel_read_file hook
module: Call security_kernel_post_load_data()
firmware_loader: Use security_post_load_data()
LSM: Introduce kernel_post_load_data() hook
fs/kernel_read_file: Add file_size output argument
fs/kernel_read_file: Switch buffer size arg to size_t
fs/kernel_read_file: Remove redundant size argument
...
|
|
These routines are used in places outside of exec(2), so in preparation
for refactoring them, move them into a separate source file,
fs/kernel_read_file.c.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Scott Branden <scott.branden@broadcom.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-5-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Move kernel_read_file* out of linux/fs.h to its own linux/kernel_read_file.h
include file. That header gets pulled in just about everywhere
and doesn't really need functions not related to the general fs interface.
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: James Morris <jamorris@linux.microsoft.com>
Link: https://lore.kernel.org/r/20200706232309.12010-2-scott.branden@broadcom.com
Link: https://lore.kernel.org/r/20201002173828.2099543-4-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
FIRMWARE_PREALLOC_BUFFER is a "how", not a "what", and confuses the LSMs
that are interested in filtering between types of things. The "how"
should be an internal detail made uninteresting to the LSMs.
Fixes: a098ecd2fa7d ("firmware: support loading into a pre-allocated buffer")
Fixes: fd90bc559bfb ("ima: based on policy verify firmware signatures (pre-allocated buffer)")
Fixes: 4f0496d8ffa3 ("ima: based on policy warn about loading firmware (pre-allocated buffer)")
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Scott Branden <scott.branden@broadcom.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20201002173828.2099543-2-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Grab actual references to the files_struct. To avoid circular references
issues due to this, we add a per-task note that keeps track of what
io_uring contexts a task has used. When the tasks execs or exits its
assigned files, we cancel requests based on this tracking.
With that, we can grab proper references to the files table, and no
longer need to rely on stashing away ring_fd and ring_file to check
if the ring_fd may have been closed.
Cc: stable@vger.kernel.org # v5.5+
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
|
Reading and modifying current->mm and current->active_mm and switching
mm should be done with irqs off, to prevent races seeing an intermediate
state.
This is similar to commit 38cf307c1f20 ("mm: fix kthread_use_mm() vs TLB
invalidate"). At exec-time when the new mm is activated, the old one
should usually be single-threaded and no longer used, unless something
else is holding an mm_users reference (which may be possible).
Absent other mm_users, there is also a race with preemption and lazy tlb
switching. Consider the kernel_execve case where the current thread is
using a lazy tlb active mm:
call_usermodehelper()
kernel_execve()
old_mm = current->mm;
active_mm = current->active_mm;
*** preempt *** --------------------> schedule()
prev->active_mm = NULL;
mmdrop(prev active_mm);
...
<-------------------- schedule()
current->mm = mm;
current->active_mm = mm;
if (!old_mm)
mmdrop(active_mm);
If we switch back to the kernel thread from a different mm, there is a
double free of the old active_mm, and a missing free of the new one.
Closing this race only requires interrupts to be disabled while ->mm
and ->active_mm are being switched, but the TLB problem requires also
holding interrupts off over activate_mm. Unfortunately not all archs
can do that yet, e.g., arm defers the switch if irqs are disabled and
expects finish_arch_post_lock_switch() to be called to complete the
flush; um takes a blocking lock in activate_mm().
So as a first step, disable interrupts across the mm/active_mm updates
to close the lazy tlb preempt race, and provide an arch option to
extend that to activate_mm which allows architectures doing IPI based
TLB shootdowns to close the second race.
This is a bit ugly, but in the interest of fixing the bug and backporting
before all architectures are converted this is a compromise.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914045219.3736466-2-npiggin@gmail.com
|
|
After the cleanup of page fault accounting, gup does not need to pass
task_struct around any more. Remove that parameter in the whole gup
stack.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Link: http://lkml.kernel.org/r/20200707225021.200906-26-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The path_noexec() check, like the regular file check, was happening too
late, letting LSMs see impossible execve()s. Check it earlier as well in
may_open() and collect the redundant fs/exec.c path_noexec() test under
the same robustness comment as the S_ISREG() check.
My notes on the call path, and related arguments, checks, etc:
do_open_execat()
struct open_flags open_exec_flags = {
.open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
.acc_mode = MAY_EXEC,
...
do_filp_open(dfd, filename, open_flags)
path_openat(nameidata, open_flags, flags)
file = alloc_empty_file(open_flags, current_cred());
do_open(nameidata, file, open_flags)
may_open(path, acc_mode, open_flag)
/* new location of MAY_EXEC vs path_noexec() test */
inode_permission(inode, MAY_OPEN | acc_mode)
security_inode_permission(inode, acc_mode)
vfs_open(path, file)
do_dentry_open(file, path->dentry->d_inode, open)
security_file_open(f)
open()
/* old location of path_noexec() test */
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Link: http://lkml.kernel.org/r/20200605160013.3954297-4-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The execve(2)/uselib(2) syscalls have always rejected non-regular files.
Recently, it was noticed that a deadlock was introduced when trying to
execute pipes, as the S_ISREG() test was happening too late. This was
fixed in commit 73601ea5b7b1 ("fs/open.c: allow opening only regular files
during execve()"), but it was added after inode_permission() had already
run, which meant LSMs could see bogus attempts to execute non-regular
files.
Move the test into the other inode type checks (which already look for
other pathological conditions[1]). Since there is no need to use
FMODE_EXEC while we still have access to "acc_mode", also switch the test
to MAY_EXEC.
Also include a comment with the redundant S_ISREG() checks at the end of
execve(2)/uselib(2) to note that they are present to avoid any mistakes.
My notes on the call path, and related arguments, checks, etc:
do_open_execat()
struct open_flags open_exec_flags = {
.open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
.acc_mode = MAY_EXEC,
...
do_filp_open(dfd, filename, open_flags)
path_openat(nameidata, open_flags, flags)
file = alloc_empty_file(open_flags, current_cred());
do_open(nameidata, file, open_flags)
may_open(path, acc_mode, open_flag)
/* new location of MAY_EXEC vs S_ISREG() test */
inode_permission(inode, MAY_OPEN | acc_mode)
security_inode_permission(inode, acc_mode)
vfs_open(path, file)
do_dentry_open(file, path->dentry->d_inode, open)
/* old location of FMODE_EXEC vs S_ISREG() test */
security_file_open(f)
open()
[1] https://lore.kernel.org/lkml/202006041910.9EF0C602@keescook/
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Link: http://lkml.kernel.org/r/20200605160013.3954297-3-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "Relocate execve() sanity checks", v2.
While looking at the code paths for the proposed O_MAYEXEC flag, I saw
some things that looked like they should be fixed up.
exec: Change uselib(2) IS_SREG() failure to EACCES
This just regularizes the return code on uselib(2).
exec: Move S_ISREG() check earlier
This moves the S_ISREG() check even earlier than it was already.
exec: Move path_noexec() check earlier
This adds the path_noexec() check to the same place as the
S_ISREG() check.
This patch (of 3):
Change uselib(2)' S_ISREG() error return to EACCES instead of EINVAL so
the behavior matches execve(2), and the seemingly documented value. The
"not a regular file" failure mode of execve(2) is explicitly
documented[1], but it is not mentioned in uselib(2)[2] which does,
however, say that open(2) and mmap(2) errors may apply. The documentation
for open(2) does not include a "not a regular file" error[3], but mmap(2)
does[4], and it is EACCES.
[1] http://man7.org/linux/man-pages/man2/execve.2.html#ERRORS
[2] http://man7.org/linux/man-pages/man2/uselib.2.html#ERRORS
[3] http://man7.org/linux/man-pages/man2/open.2.html#ERRORS
[4] http://man7.org/linux/man-pages/man2/mmap.2.html#ERRORS
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Link: http://lkml.kernel.org/r/20200605160013.3954297-1-keescook@chromium.org
Link: http://lkml.kernel.org/r/20200605160013.3954297-2-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Both exec and exit want to ensure that the uaccess routines actually do
access user pointers. Use the newly added force_uaccess_begin helper
instead of an open coded set_fs for that to prepare for kernel builds
where set_fs() does not exist.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Link: http://lkml.kernel.org/r/20200710135706.537715-7-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
To allow the kernel not to play games with set_fs to call exec
implement kernel_execve. The function kernel_execve takes pointers
into kernel memory and copies the values pointed to onto the new
userspace stack.
The calls with arguments from kernel space of do_execve are replaced
with calls to kernel_execve.
The calls do_execve and do_execveat are made static as there are now
no callers outside of exec.
The comments that mention do_execve are updated to refer to
kernel_execve or execve depending on the circumstances. In addition
to correcting the comments, this makes it easy to grep for do_execve
and verify it is not used.
Inspired-by: https://lkml.kernel.org/r/20200627072704.2447163-1-hch@lst.de
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/87wo365ikj.fsf@x220.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
In preparation for implementiong kernel_execve (which will take kernel
pointers not userspace pointers) factor out bprm_stack_limits out of
prepare_arg_pages. This separates the counting which depends upon the
getting data from userspace from the calculations of the stack limits
which is usable in kernel_execve.
The remove prepare_args_pages and compute bprm->argc and bprm->envc
directly in do_execveat_common, before bprm_stack_limits is called.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lkml.kernel.org/r/87365u6x60.fsf@x220.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Currently it is necessary for the usermode helper code and the code
that launches init to use set_fs so that pages coming from the kernel
look like they are coming from userspace.
To allow that usage of set_fs to be removed cleanly the argument
copying from userspace needs to happen earlier. Factor bprm_execve
out of do_execve_common to separate out the copying of arguments
to the newe stack, and the rest of exec.
In separating bprm_execve from do_execve_common the copying
of the arguments onto the new stack happens earlier.
As the copying of the arguments does not depend any security hooks,
files, the file table, current->in_execve, current->fs->in_exec,
bprm->unsafe, or creds this is safe.
Likewise the security hook security_creds_for_exec does not depend upon
preventing the argument copying from happening.
In addition to making it possible to implement kernel_execve that
performs the copying differently, this separation of bprm_execve from
do_execve_common makes for a nice separation of responsibilities making
the exec code easier to navigate.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lkml.kernel.org/r/878sfm6x6x.fsf@x220.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Currently it is necessary for the usermode helper code and the code that
launches init to use set_fs so that pages coming from the kernel look like
they are coming from userspace.
To allow that usage of set_fs to be removed cleanly the argument copying
from userspace needs to happen earlier. Move the allocation and
initialization of bprm->mm into alloc_bprm so that the bprm->mm is
available early to store the new user stack into. This is a prerequisite
for copying argv and envp into the new user stack early before ther rest of
exec.
To keep the things consistent the cleanup of bprm->mm is moved into
free_bprm. So that bprm->mm will be cleaned up whenever bprm->mm is
allocated and free_bprm are called.
Moving bprm_mm_init earlier is safe as it does not depend on any files,
current->in_execve, current->fs->in_exec, bprm->unsafe, or the if the file
table is shared. (AKA bprm_mm_init does not depend on any of the code that
happens between alloc_bprm and where it was previously called.)
This moves bprm->mm cleanup after current->fs->in_exec is set to 0. This
is safe because current->fs->in_exec is only used to preventy taking an
additional reference on the fs_struct.
This moves bprm->mm cleanup after current->in_execve is set to 0. This is
safe because current->in_execve is only used by the lsms (apparmor and
tomoyou) and always for LSM specific functions, never for anything to do
with the mm.
This adds bprm->mm cleanup into the successful return path. This is safe
because being on the successful return path implies that begin_new_exec
succeeded and set brpm->mm to NULL. As bprm->mm is NULL bprm cleanup I am
moving into free_bprm will do nothing.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lkml.kernel.org/r/87eepe6x7p.fsf@x220.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Currently it is necessary for the usermode helper code and the code
that launches init to use set_fs so that pages coming from the kernel
look like they are coming from userspace.
To allow that usage of set_fs to be removed cleanly the argument
copying from userspace needs to happen earlier. Move the computation
of bprm->filename and possible allocation of a name in the case
of execveat into alloc_bprm to make that possible.
The exectuable name, the arguments, and the environment are
copied into the new usermode stack which is stored in bprm
until exec passes the point of no return.
As the executable name is copied first onto the usermode stack
it needs to be known. As there are no dependencies to computing
the executable name, compute it early in alloc_bprm.
As an implementation detail if the filename needs to be generated
because it embeds a file descriptor store that filename in a new field
bprm->fdpath, and free it in free_bprm. Previously this was done in
an independent variable pathbuf. I have renamed pathbuf fdpath
because fdpath is more suggestive of what kind of path is in the
variable. I moved fdpath into struct linux_binprm because it is
tightly tied to the other variables in struct linux_binprm, and as
such is needed to allow the call alloc_binprm to move.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lkml.kernel.org/r/87k0z66x8f.fsf@x220.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Currently it is necessary for the usermode helper code and the code
that launches init to use set_fs so that pages coming from the kernel
look like they are coming from userspace.
To allow that usage of set_fs to be removed cleanly the argument
copying from userspace needs to happen earlier. Move the allocation
of the bprm into it's own function (alloc_bprm) and move the call of
alloc_bprm before unshare_files so that bprm can ultimately be
allocated, the arguments can be placed on the new stack, and then the
bprm can be passed into the core of exec.
Neither the allocation of struct binprm nor the unsharing depend upon each
other so swapping the order in which they are called is trivially safe.
To keep things consistent the order of cleanup at the end of
do_execve_common swapped to match the order of initialization.
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/87pn8y6x9a.fsf@x220.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Now that the last callser has been removed remove this code from exec.
For anyone thinking of resurrecing do_execve_file please note that
the code was buggy in several fundamental ways.
- It did not ensure the file it was passed was read-only and that
deny_write_access had been called on it. Which subtlely breaks
invaniants in exec.
- The caller of do_execve_file was expected to hold and put a
reference to the file, but an extra reference for use by exec was
not taken so that when exec put it's reference to the file an
underflow occured on the file reference count.
- The point of the interface was so that a pathname did not need to
exist. Which breaks pathname based LSMs.
Tetsuo Handa originally reported these issues[1]. While it was clear
that deny_write_access was missing the fundamental incompatibility
with the passed in O_RDWR filehandle was not immediately recognized.
All of these issues were fixed by modifying the usermode driver code
to have a path, so it did not need this hack.
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
[1] https://lore.kernel.org/linux-fsdevel/2a8775b4-1dd5-9d5c-aa42-9872445e0942@i-love.sakura.ne.jp/
v1: https://lkml.kernel.org/r/871rm2f0hi.fsf_-_@x220.int.ebiederm.org
v2: https://lkml.kernel.org/r/87lfk54p0m.fsf_-_@x220.int.ebiederm.org
Link: https://lkml.kernel.org/r/20200702164140.4468-10-ebiederm@xmission.com
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Convert comments that reference mmap_sem to reference mmap_lock instead.
[akpm@linux-foundation.org: fix up linux-next leftovers]
[akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil]
[akpm@linux-foundation.org: more linux-next fixups, per Michel]
Signed-off-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
This change converts the existing mmap_sem rwsem calls to use the new mmap
locking API instead.
The change is generated using coccinelle with the following rule:
// spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir .
@@
expression mm;
@@
(
-init_rwsem
+mmap_init_lock
|
-down_write
+mmap_write_lock
|
-down_write_killable
+mmap_write_lock_killable
|
-down_write_trylock
+mmap_write_trylock
|
-up_write
+mmap_write_unlock
|
-downgrade_write
+mmap_write_downgrade
|
-down_read
+mmap_read_lock
|
-down_read_killable
+mmap_read_lock_killable
|
-down_read_trylock
+mmap_read_trylock
|
-up_read
+mmap_read_unlock
)
-(&mm->mmap_sem)
+(mm)
Signed-off-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
read_code operates on user addresses.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Link: http://lkml.kernel.org/r/20200515143646.3857579-27-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Only build read_code when binary formats that use it are built into the
kernel.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Link: http://lkml.kernel.org/r/20200515143646.3857579-26-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Merge yet more updates from Andrew Morton:
- More MM work. 100ish more to go. Mike Rapoport's "mm: remove
__ARCH_HAS_5LEVEL_HACK" series should fix the current ppc issue
- Various other little subsystems
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (127 commits)
lib/ubsan.c: fix gcc-10 warnings
tools/testing/selftests/vm: remove duplicate headers
selftests: vm: pkeys: fix multilib builds for x86
selftests: vm: pkeys: use the correct page size on powerpc
selftests/vm/pkeys: override access right definitions on powerpc
selftests/vm/pkeys: test correct behaviour of pkey-0
selftests/vm/pkeys: introduce a sub-page allocator
selftests/vm/pkeys: detect write violation on a mapped access-denied-key page
selftests/vm/pkeys: associate key on a mapped page and detect write violation
selftests/vm/pkeys: associate key on a mapped page and detect access violation
selftests/vm/pkeys: improve checks to determine pkey support
selftests/vm/pkeys: fix assertion in test_pkey_alloc_exhaust()
selftests/vm/pkeys: fix number of reserved powerpc pkeys
selftests/vm/pkeys: introduce powerpc support
selftests/vm/pkeys: introduce generic pkey abstractions
selftests: vm: pkeys: use the correct huge page size
selftests/vm/pkeys: fix alloc_random_pkey() to make it really random
selftests/vm/pkeys: fix assertion in pkey_disable_set/clear()
selftests/vm/pkeys: fix pkey_disable_clear()
selftests: vm: pkeys: add helpers for pkey bits
...
|
|
Currently copy_string_kernel is just a wrapper around copy_strings that
simplifies the calling conventions and uses set_fs to allow passing a
kernel pointer. But due to the fact the we only need to handle a single
kernel argument pointer, the logic can be sigificantly simplified while
getting rid of the set_fs.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Link: http://lkml.kernel.org/r/20200501104105.2621149-3-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
copy_strings_kernel is always used with a single argument,
adjust the calling convention to that.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Link: http://lkml.kernel.org/r/20200501104105.2621149-2-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull execve updates from Eric Biederman:
"Last cycle for the Nth time I ran into bugs and quality of
implementation issues related to exec that could not be easily be
fixed because of the way exec is implemented. So I have been digging
into exec and cleanup up what I can.
I don't think I have exec sorted out enough to fix the issues I
started with but I have made some headway this cycle with 4 sets of
changes.
- promised cleanups after introducing exec_update_mutex
- trivial cleanups for exec
- control flow simplifications
- remove the recomputation of bprm->cred
The net result is code that is a bit easier to understand and work
with and a decrease in the number of lines of code (if you don't count
the added tests)"
* 'exec-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (24 commits)
exec: Compute file based creds only once
exec: Add a per bprm->file version of per_clear
binfmt_elf_fdpic: fix execfd build regression
selftests/exec: Add binfmt_script regression test
exec: Remove recursion from search_binary_handler
exec: Generic execfd support
exec/binfmt_script: Don't modify bprm->buf and then return -ENOEXEC
exec: Move the call of prepare_binprm into search_binary_handler
exec: Allow load_misc_binary to call prepare_binprm unconditionally
exec: Convert security_bprm_set_creds into security_bprm_repopulate_creds
exec: Factor security_bprm_creds_for_exec out of security_bprm_set_creds
exec: Teach prepare_exec_creds how exec treats uids & gids
exec: Set the point of no return sooner
exec: Move handling of the point of no return to the top level
exec: Run sync_mm_rss before taking exec_update_mutex
exec: Fix spelling of search_binary_handler in a comment
exec: Move the comment from above de_thread to above unshare_sighand
exec: Rename flush_old_exec begin_new_exec
exec: Move most of setup_new_exec into flush_old_exec
exec: In setup_new_exec cache current in the local variable me
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull proc updates from Eric Biederman:
"This has four sets of changes:
- modernize proc to support multiple private instances
- ensure we see the exit of each process tid exactly
- remove has_group_leader_pid
- use pids not tasks in posix-cpu-timers lookup
Alexey updated proc so each mount of proc uses a new superblock. This
allows people to actually use mount options with proc with no fear of
messing up another mount of proc. Given the kernel's internal mounts
of proc for things like uml this was a real problem, and resulted in
Android's hidepid mount options being ignored and introducing security
issues.
The rest of the changes are small cleanups and fixes that came out of
my work to allow this change to proc. In essence it is swapping the
pids in de_thread during exec which removes a special case the code
had to handle. Then updating the code to stop handling that special
case"
* 'proc-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
proc: proc_pid_ns takes super_block as an argument
remove the no longer needed pid_alive() check in __task_pid_nr_ns()
posix-cpu-timers: Replace __get_task_for_clock with pid_for_clock
posix-cpu-timers: Replace cpu_timer_pid_type with clock_pid_type
posix-cpu-timers: Extend rcu_read_lock removing task_struct references
signal: Remove has_group_leader_pid
exec: Remove BUG_ON(has_group_leader_pid)
posix-cpu-timer: Unify the now redundant code in lookup_task
posix-cpu-timer: Tidy up group_leader logic in lookup_task
proc: Ensure we see the exit of each process tid exactly once
rculist: Add hlists_swap_heads_rcu
proc: Use PIDTYPE_TGID in next_tgid
Use proc_pid_ns() to get pid_namespace from the proc superblock
proc: use named enums for better readability
proc: use human-readable values for hidepid
docs: proc: add documentation for "hidepid=4" and "subset=pid" options and new mount behavior
proc: add option to mount only a pids subset
proc: instantiate only pids that we can ptrace on 'hidepid=4' mount option
proc: allow to mount many instances of proc in one pid namespace
proc: rename struct proc_fs_info to proc_fs_opts
|
|
Move the computation of creds from prepare_binfmt into begin_new_exec
so that the creds need only be computed once. This is just code
reorganization no semantic changes of any kind are made.
Moving the computation is safe. I have looked through the kernel and
verified none of the binfmts look at bprm->cred directly, and that
there are no helpers that look at bprm->cred indirectly. Which means
that it is not a problem to compute the bprm->cred later in the
execution flow as it is not used until it becomes current->cred.
A new function bprm_creds_from_file is added to contain the work that
needs to be done. bprm_creds_from_file first computes which file
bprm->executable or most likely bprm->file that the bprm->creds
will be computed from.
The funciton bprm_fill_uid is updated to receive the file instead of
accessing bprm->file. The now unnecessary work needed to reset the
bprm->cred->euid, and bprm->cred->egid is removed from brpm_fill_uid.
A small comment to document that bprm_fill_uid now only deals with the
work to handle suid and sgid files. The default case is already
heandled by prepare_exec_creds.
The function security_bprm_repopulate_creds is renamed
security_bprm_creds_from_file and now is explicitly passed the file
from which to compute the creds. The documentation of the
bprm_creds_from_file security hook is updated to explain when the hook
is called and what it needs to do. The file is passed from
cap_bprm_creds_from_file into get_file_caps so that the caps are
computed for the appropriate file. The now unnecessary work in
cap_bprm_creds_from_file to reset the ambient capabilites has been
removed. A small comment to document that the work of
cap_bprm_creds_from_file is to read capabilities from the files
secureity attribute and derive capabilities from the fact the
user had uid 0 has been added.
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
There is a small bug in the code that recomputes parts of bprm->cred
for every bprm->file. The code never recomputes the part of
clear_dangerous_personality_flags it is responsible for.
Which means that in practice if someone creates a sgid script
the interpreter will not be able to use any of:
READ_IMPLIES_EXEC
ADDR_NO_RANDOMIZE
ADDR_COMPAT_LAYOUT
MMAP_PAGE_ZERO.
This accentially clearing of personality flags probably does
not matter in practice because no one has complained
but it does make the code more difficult to understand.
Further remaining bug compatible prevents the recomputation from being
removed and replaced by simply computing bprm->cred once from the
final bprm->file.
Making this change removes the last behavior difference between
computing bprm->creds from the final file and recomputing
bprm->cred several times. Which allows this behavior change
to be justified for it's own reasons, and for any but hunts
looking into why the behavior changed to wind up here instead
of in the code that will follow that computes bprm->cred
from the final bprm->file.
This small logic bug appears to have existed since the code
started clearing dangerous personality bits.
History Tree: git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Fixes: 1bb0fa189c6a ("[PATCH] NX: clean up legacy binary support")
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Recursion in kernel code is generally a bad idea as it can overflow
the kernel stack. Recursion in exec also hides that the code is
looping and that the loop changes bprm->file.
Instead of recursing in search_binary_handler have the methods that
would recurse set bprm->interpreter and return 0. Modify exec_binprm
to loop when bprm->interpreter is set. Consolidate all of the
reassignments of bprm->file in that loop to make it clear what is
going on.
The structure of the new loop in exec_binprm is that all errors return
immediately, while successful completion (ret == 0 &&
!bprm->interpreter) just breaks out of the loop and runs what
exec_bprm has always run upon successful completion.
Fail if the an interpreter is being call after execfd has been set.
The code has never properly handled an interpreter being called with
execfd being set and with reassignments of bprm->file and the
assignment of bprm->executable in generic code it has finally become
possible to test and fail when if this problematic condition happens.
With the reassignments of bprm->file and the assignment of
bprm->executable moved into the generic code add a test to see if
bprm->executable is being reassigned.
In search_binary_handler remove the test for !bprm->file. With all
reassignments of bprm->file moved to exec_binprm bprm->file can never
be NULL in search_binary_handler.
Link: https://lkml.kernel.org/r/87sgfwyd84.fsf_-_@x220.int.ebiederm.org
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Most of the support for passing the file descriptor of an executable
to an interpreter already lives in the generic code and in binfmt_elf.
Rework the fields in binfmt_elf that deal with executable file
descriptor passing to make executable file descriptor passing a first
class concept.
Move the fd_install from binfmt_misc into begin_new_exec after the new
creds have been installed. This means that accessing the file through
/proc/<pid>/fd/N is able to see the creds for the new executable
before allowing access to the new executables files.
Performing the install of the executables file descriptor after
the point of no return also means that nothing special needs to
be done on error. The exiting of the process will close all
of it's open files.
Move the would_dump from binfmt_misc into begin_new_exec right
after would_dump is called on the bprm->file. This makes it
obvious this case exists and that no nesting of bprm->file is
currently supported.
In binfmt_misc the movement of fd_install into generic code means
that it's special error exit path is no longer needed.
Link: https://lkml.kernel.org/r/87y2poyd91.fsf_-_@x220.int.ebiederm.org
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
The code in prepare_binary_handler needs to be run every time
search_binary_handler is called so move the call into search_binary_handler
itself to make the code simpler and easier to understand.
Link: https://lkml.kernel.org/r/87d070zrvx.fsf_-_@x220.int.ebiederm.org
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Add a flag preserve_creds that binfmt_misc can set to prevent
credentials from being updated. This allows binfmt_misc to always
call prepare_binprm. Allowing the credential computation logic to be
consolidated.
Not replacing the credentials with the interpreters credentials is
safe because because an open file descriptor to the executable is
passed to the interpreter. As the interpreter does not need to
reopen the executable it is guaranteed to see the same file that
exec sees.
Ref: c407c033de84 ("[PATCH] binfmt_misc: improve calculation of interpreter's credentials")
Link: https://lkml.kernel.org/r/87imgszrwo.fsf_-_@x220.int.ebiederm.org
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Rename bprm->cap_elevated to bprm->active_secureexec and initialize it
in prepare_binprm instead of in cap_bprm_set_creds. Initializing
bprm->active_secureexec in prepare_binprm allows multiple
implementations of security_bprm_repopulate_creds to play nicely with
each other.
Rename security_bprm_set_creds to security_bprm_reopulate_creds to
emphasize that this path recomputes part of bprm->cred. This
recomputation avoids the time of check vs time of use problems that
are inherent in unix #! interpreters.
In short two renames and a move in the location of initializing
bprm->active_secureexec.
Link: https://lkml.kernel.org/r/87o8qkzrxp.fsf_-_@x220.int.ebiederm.org
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Today security_bprm_set_creds has several implementations:
apparmor_bprm_set_creds, cap_bprm_set_creds, selinux_bprm_set_creds,
smack_bprm_set_creds, and tomoyo_bprm_set_creds.
Except for cap_bprm_set_creds they all test bprm->called_set_creds and
return immediately if it is true. The function cap_bprm_set_creds
ignores bprm->calld_sed_creds entirely.
Create a new LSM hook security_bprm_creds_for_exec that is called just
before prepare_binprm in __do_execve_file, resulting in a LSM hook
that is called exactly once for the entire of exec. Modify the bits
of security_bprm_set_creds that only want to be called once per exec
into security_bprm_creds_for_exec, leaving only cap_bprm_set_creds
behind.
Remove bprm->called_set_creds all of it's former users have been moved
to security_bprm_creds_for_exec.
Add or upate comments a appropriate to bring them up to date and
to reflect this change.
Link: https://lkml.kernel.org/r/87v9kszrzh.fsf_-_@x220.int.ebiederm.org
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Casey Schaufler <casey@schaufler-ca.com> # For the LSM and Smack bits
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
The change to exec is relevant to the cleanup work I have been doing.
Merge it here so that I can build on top of it, and so hopefully
that other merge logic can pick up on this and see how to deal
with the conflict between that change and my exec cleanup work.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
I goofed when I added mm->user_ns support to would_dump. I missed the
fact that in the case of binfmt_loader, binfmt_em86, binfmt_misc, and
binfmt_script bprm->file is reassigned. Which made the move of
would_dump from setup_new_exec to __do_execve_file before exec_binprm
incorrect as it can result in would_dump running on the script instead
of the interpreter of the script.
The net result is that the code stopped making unreadable interpreters
undumpable. Which allows them to be ptraced and written to disk
without special permissions. Oops.
The move was necessary because the call in set_new_exec was after
bprm->mm was no longer valid.
To correct this mistake move the misplaced would_dump from
__do_execve_file into flos_old_exec, before exec_mmap is called.
I tested and confirmed that without this fix I can attach with gdb to
a script with an unreadable interpreter, and with this fix I can not.
Cc: stable@vger.kernel.org
Fixes: f84df2a6f268 ("exec: Ensure mm->user_ns contains the execed files")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Make the code more robust by marking the point of no return sooner.
This ensures that future code changes don't need to worry about how
they return errors if they are past this point.
This results in no actual change in behavior as __do_execve_file does
not force SIGSEGV when there is a pending fatal signal pending past
the point of no return. Further the only error returns from de_thread
and exec_mmap that can occur result in fatal signals being pending.
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/87sgga5klu.fsf_-_@x220.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Move the handing of the point of no return from search_binary_handler
into __do_execve_file so that it is easier to find, and to keep
things robust in the face of change.
Make it clear that an existing fatal signal will take precedence over
a forced SIGSEGV by not forcing SIGSEGV if a fatal signal is already
pending. This does not change the behavior but it saves a reader
of the code the tedium of reading and understanding force_sig
and the signal delivery code.
Update the comment in begin_new_exec about where SIGSEGV is forced.
Keep point_of_no_return from being a mystery by documenting
what the code is doing where it forces SIGSEGV if the
code is past the point of no return.
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/87y2q25knl.fsf_-_@x220.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Like exec_mm_release sync_mm_rss is about flushing out the state of
the old_mm, which does not need to happen under exec_update_mutex.
Make this explicit by moving sync_mm_rss outside of exec_update_mutex.
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/875zd66za3.fsf_-_@x220.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Link: https://lkml.kernel.org/r/87h7wq6zc1.fsf_-_@x220.int.ebiederm.org
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
The comment describes work that now happens in unshare_sighand so
move the comment where it makes sense.
Link: https://lkml.kernel.org/r/87mu6i6zcs.fsf_-_@x220.int.ebiederm.org
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
There is and has been for a very long time been a lot more going on in
flush_old_exec than just flushing the old state. After the movement
of code from setup_new_exec there is a whole lot more going on than
just flushing the old executables state.
Rename flush_old_exec to begin_new_exec to more accurately reflect
what this function does.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
The current idiom for the callers is:
flush_old_exec(bprm);
set_personality(...);
setup_new_exec(bprm);
In 2010 Linus split flush_old_exec into flush_old_exec and
setup_new_exec. With the intention that setup_new_exec be what is
called after the processes new personality is set.
Move the code that doesn't depend upon the personality from
setup_new_exec into flush_old_exec. This is to facilitate future
changes by having as much code together in one function as possible.
To see why it is safe to move this code please note that effectively
this change moves the personality setting in the binfmt and the following
three lines of code after everything except unlocking the mutexes:
arch_pick_mmap_layout
arch_setup_new_exec
mm->task_size = TASK_SIZE
The function arch_pick_mmap_layout at most sets:
mm->get_unmapped_area
mm->mmap_base
mm->mmap_legacy_base
mm->mmap_compat_base
mm->mmap_compat_legacy_base
which nothing in flush_old_exec or setup_new_exec depends on.
The function arch_setup_new_exec only sets architecture specific
state and the rest of the functions only deal in state that applies
to all architectures.
The last line just sets mm->task_size and again nothing in flush_old_exec
or setup_new_exec depend on task_size.
Ref: 221af7f87b97 ("Split 'flush_old_exec' into two functions")
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
At least gcc 8.3 when generating code for x86_64 has a hard time
consolidating multiple calls to current aka get_current(), and winds
up unnecessarily rereading %gs:current_task several times in
setup_new_exec.
Caching the value of current in the local variable of me generates
slightly better and shorter assembly.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
The two functions are now always called one right after the
other so merge them together to make future maintenance easier.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Update the comments and make the code easier to understand by
renaming this flag.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
With install_exec_creds updated to follow immediately after
setup_new_exec, the failure of unshare_sighand is the only
code path where exec_update_mutex is held but not explicitly
unlocked.
Update that code path to explicitly unlock exec_update_mutex.
Remove the unlocking of exec_update_mutex from free_bprm.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
With the introduction of exchange_tids thread_group_leader and
has_group_leader_pid have become equivalent. Further at this point in the
code a thread group has exactly two threads, the previous thread_group_leader
that is waiting to be reaped and tsk. So we know it is impossible for tsk to
be the thread_group_leader.
This is also the last user of has_group_leader_pid so removing this check
will allow has_group_leader_pid to be removed.
So remove the "BUG_ON(has_group_leader_pid)" that will never fire.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
When the thread group leader changes during exec and the old leaders
thread is reaped proc_flush_pid will flush the dentries for the entire
process because the leader still has it's original pid.
Fix this by exchanging the pids in an rcu safe manner,
and wrapping the code to do that up in a helper exchange_tids.
When I removed switch_exec_pids and introduced this behavior
in d73d65293e3e ("[PATCH] pidhash: kill switch_exec_pids") there
really was nothing that cared as flushing happened with
the cached dentry and de_thread flushed both of them on exec.
This lack of fully exchanging pids became a problem a few months later
when I introduced 48e6484d4902 ("[PATCH] proc: Rewrite the proc dentry
flush on exit optimization"). Which overlooked the de_thread case
was no longer swapping pids, and I was looking up proc dentries
by task->pid.
The current behavior isn't properly a bug as everything in proc will
continue to work correctly just a little bit less efficiently. Fix
this just so there are no little surprise corner cases waiting to bite
people.
-- Oleg points out this could be an issue in next_tgid in proc where
has_group_leader_pid is called, and reording some of the assignments
should fix that.
-- Oleg points out this will break the 10 year old hack in __exit_signal.c
> /*
> * This can only happen if the caller is de_thread().
> * FIXME: this is the temporary hack, we should teach
> * posix-cpu-timers to handle this case correctly.
> */
> if (unlikely(has_group_leader_pid(tsk)))
> posix_cpu_timers_exit_group(tsk);
The code in next_tgid has been changed to use PIDTYPE_TGID,
and the posix cpu timers code has been fixed so it does not
need the 10 year old hack, so this should be safe to merge
now.
Link: https://lore.kernel.org/lkml/87h7x3ajll.fsf_-_@x220.int.ebiederm.org/
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Fixes: 48e6484d4902 ("[PATCH] proc: Rewrite the proc dentry flush on exit optimization").
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull exec/proc updates from Eric Biederman:
"This contains two significant pieces of work: the work to sort out
proc_flush_task, and the work to solve a deadlock between strace and
exec.
Fixing proc_flush_task so that it no longer requires a persistent
mount makes improvements to proc possible. The removal of the
persistent mount solves an old regression that that caused the hidepid
mount option to only work on remount not on mount. The regression was
found and reported by the Android folks. This further allows Alexey
Gladkov's work making proc mount options specific to an individual
mount of proc to move forward.
The work on exec starts solving a long standing issue with exec that
it takes mutexes of blocking userspace applications, which makes exec
extremely deadlock prone. For the moment this adds a second mutex with
a narrower scope that handles all of the easy cases. Which makes the
tricky cases easy to spot. With a little luck the code to solve those
deadlocks will be ready by next merge window"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (25 commits)
signal: Extend exec_id to 64bits
pidfd: Use new infrastructure to fix deadlocks in execve
perf: Use new infrastructure to fix deadlocks in execve
proc: io_accounting: Use new infrastructure to fix deadlocks in execve
proc: Use new infrastructure to fix deadlocks in execve
kernel/kcmp.c: Use new infrastructure to fix deadlocks in execve
kernel: doc: remove outdated comment cred.c
mm: docs: Fix a comment in process_vm_rw_core
selftests/ptrace: add test cases for dead-locks
exec: Fix a deadlock in strace
exec: Add exec_update_mutex to replace cred_guard_mutex
exec: Move exec_mmap right after de_thread in flush_old_exec
exec: Move cleanup of posix timers on exec out of de_thread
exec: Factor unshare_sighand out of de_thread and call it separately
exec: Only compute current once in flush_old_exec
pid: Improve the comment about waiting in zap_pid_ns_processes
proc: Remove the now unnecessary internal mount of proc
uml: Create a private mount of proc for mconsole
uml: Don't consult current to find the proc_mnt in mconsole_proc
proc: Use a list of inodes to flush from proc
...
|
|
Replace the 32bit exec_id with a 64bit exec_id to make it impossible
to wrap the exec_id counter. With care an attacker can cause exec_id
wrap and send arbitrary signals to a newly exec'd parent. This
bypasses the signal sending checks if the parent changes their
credentials during exec.
The severity of this problem can been seen that in my limited testing
of a 32bit exec_id it can take as little as 19s to exec 65536 times.
Which means that it can take as little as 14 days to wrap a 32bit
exec_id. Adam Zabrocki has succeeded wrapping the self_exe_id in 7
days. Even my slower timing is in the uptime of a typical server.
Which means self_exec_id is simply a speed bump today, and if exec
gets noticably faster self_exec_id won't even be a speed bump.
Extending self_exec_id to 64bits introduces a problem on 32bit
architectures where reading self_exec_id is no longer atomic and can
take two read instructions. Which means that is is possible to hit
a window where the read value of exec_id does not match the written
value. So with very lucky timing after this change this still
remains expoiltable.
I have updated the update of exec_id on exec to use WRITE_ONCE
and the read of exec_id in do_notify_parent to use READ_ONCE
to make it clear that there is no locking between these two
locations.
Link: https://lore.kernel.org/kernel-hardening/20200324215049.GA3710@pi3.com.pl
Fixes: 2.3.23pre2
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
The cred_guard_mutex is problematic as it is held over possibly
indefinite waits for userspace. The possible indefinite waits for
userspace that I have identified are: The cred_guard_mutex is held in
PTRACE_EVENT_EXIT waiting for the tracer. The cred_guard_mutex is
held over "put_user(0, tsk->clear_child_tid)" in exit_mm(). The
cred_guard_mutex is held over "get_user(futex_offset, ...") in
exit_robust_list. The cred_guard_mutex held over copy_strings.
The functions get_user and put_user can trigger a page fault which can
potentially wait indefinitely in the case of userfaultfd or if
userspace implements part of the page fault path.
In any of those cases the userspace process that the kernel is waiting
for might make a different system call that winds up taking the
cred_guard_mutex and result in deadlock.
Holding a mutex over any of those possibly indefinite waits for
userspace does not appear necessary. Add exec_update_mutex that will
just cover updating the process during exec where the permissions and
the objects pointed to by the task struct may be out of sync.
The plan is to switch the users of cred_guard_mutex to
exec_update_mutex one by one. This lets us move forward while still
being careful and not introducing any regressions.
Link: https://lore.kernel.org/lkml/20160921152946.GA24210@dhcp22.suse.cz/
Link: https://lore.kernel.org/lkml/AM6PR03MB5170B06F3A2B75EFB98D071AE4E60@AM6PR03MB5170.eurprd03.prod.outlook.com/
Link: https://lore.kernel.org/linux-fsdevel/20161102181806.GB1112@redhat.com/
Link: https://lore.kernel.org/lkml/20160923095031.GA14923@redhat.com/
Link: https://lore.kernel.org/lkml/20170213141452.GA30203@redhat.com/
Ref: 45c1a159b85b ("Add PTRACE_O_TRACEVFORKDONE and PTRACE_O_TRACEEXIT facilities.")
Ref: 456f17cd1a28 ("[PATCH] user-vm-unlock-2.5.31-A2")
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
|
|
I have read through the code in exec_mmap and I do not see anything
that depends on sighand or the sighand lock, or on signals in anyway
so this should be safe.
This rearrangement of code has two significant benefits. It makes
the determination of passing the point of no return by testing bprm->mm
accurate. All failures prior to that point in flush_old_exec are
either truly recoverable or they are fatal.
Further this consolidates all of the possible indefinite waits for
userspace together at the top of flush_old_exec. The possible wait
for a ptracer on PTRACE_EVENT_EXIT, the possible wait for a page fault
to be resolved in clear_child_tid, and the possible wait for a page
fault in exit_robust_list.
This consolidation allows the creation of a mutex to replace
cred_guard_mutex that is not held over possible indefinite userspace
waits. Which will allow removing deadlock scenarios from the kernel.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
|
|
These functions have very little to do with de_thread move them out
of de_thread an into flush_old_exec proper so it can be more clearly
seen what flush_old_exec is doing.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
|
|
This makes the code clearer and makes it easier to implement a mutex
that is not taken over any locations that may block indefinitely waiting
for userspace.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
|
|
Make it clear that current only needs to be computed once in
flush_old_exec. This may have some efficiency improvements and it
makes the code easier to change.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
|
|
I have an experimental setup where almost every possible system
service (even early startup ones) runs in separate namespace, using a
dedicated, minimal file system. In process of minimizing the contents
of the file systems with regards to modules and firmware files, I
noticed that in my system, the firmware files are loaded from three
different mount namespaces, those of systemd-udevd, init and
systemd-networkd. The logic of the source namespace is not very clear,
it seems to depend on the driver, but the namespace of the current
process is used.
So, this patch tries to make things a bit clearer and changes the
loading of firmware files only from the mount namespace of init. This
may also improve security, though I think that using firmware files as
attack vector could be too impractical anyway.
Later, it might make sense to make the mount namespace configurable,
for example with a new file in /proc/sys/kernel/firmware_config/. That
would allow a dedicated file system only for firmware files and those
need not be present anywhere else. This configurability would make
more sense if made also for kernel modules and /sbin/modprobe. Modules
are already loaded from init namespace (usermodehelper uses kthreadd
namespace) except when directly loaded by systemd-udevd.
Instead of using the mount namespace of the current process to load
firmware files, use the mount namespace of init process.
Link: https://lore.kernel.org/lkml/bb46ebae-4746-90d9-ec5b-fce4c9328c86@gmail.com/
Link: https://lore.kernel.org/lkml/0e3f7653-c59d-9341-9db2-c88f5b988c68@gmail.com/
Signed-off-by: Topi Miettinen <toiwoton@gmail.com>
Link: https://lore.kernel.org/r/20200123125839.37168-1-toiwoton@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Pull updates from Andrew Morton:
"Most of -mm and quite a number of other subsystems: hotfixes, scripts,
ocfs2, misc, lib, binfmt, init, reiserfs, exec, dma-mapping, kcov.
MM is fairly quiet this time. Holidays, I assume"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (118 commits)
kcov: ignore fault-inject and stacktrace
include/linux/io-mapping.h-mapping: use PHYS_PFN() macro in io_mapping_map_atomic_wc()
execve: warn if process starts with executable stack
reiserfs: prevent NULL pointer dereference in reiserfs_insert_item()
init/main.c: fix misleading "This architecture does not have kernel memory protection" message
init/main.c: fix quoted value handling in unknown_bootoption
init/main.c: remove unnecessary repair_env_string in do_initcall_level
init/main.c: log arguments and environment passed to init
fs/binfmt_elf.c: coredump: allow process with empty address space to coredump
fs/binfmt_elf.c: coredump: delete duplicated overflow check
fs/binfmt_elf.c: coredump: allocate core ELF header on stack
fs/binfmt_elf.c: make BAD_ADDR() unlikely
fs/binfmt_elf.c: better codegen around current->mm
fs/binfmt_elf.c: don't copy ELF header around
fs/binfmt_elf.c: fix ->start_code calculation
fs/binfmt_elf.c: smaller code generation around auxv vector fill
lib/find_bit.c: uninline helper _find_next_bit()
lib/find_bit.c: join _find_next_bit{_le}
uapi: rename ext2_swab() to swab() and share globally in swab.h
lib/scatterlist.c: adjust indentation in __sg_alloc_table
...
|
|
There were few episodes of silent downgrade to an executable stack over
years:
1) linking innocent looking assembly file will silently add executable
stack if proper linker options is not given as well:
$ cat f.S
.intel_syntax noprefix
.text
.globl f
f:
ret
$ cat main.c
void f(void);
int main(void)
{
f();
return 0;
}
$ gcc main.c f.S
$ readelf -l ./a.out
GNU_STACK 0x0000000000000000 0x0000000000000000 0x0000000000000000
0x0000000000000000 0x0000000000000000 RWE 0x10
^^^
2) converting C99 nested function into a closure
https://nullprogram.com/blog/2019/11/15/
void intsort2(int *base, size_t nmemb, _Bool invert)
{
int cmp(const void *a, const void *b)
{
int r = *(int *)a - *(int *)b;
return invert ? -r : r;
}
qsort(base, nmemb, sizeof(*base), cmp);
}
will silently require stack trampolines while non-closure version will
not.
Without doubt this behaviour is documented somewhere, add a warning so
that developers and users can at least notice. After so many years of
x86_64 having proper executable stack support it should not cause too
many problems.
Link: http://lkml.kernel.org/r/20191208171918.GC19716@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Will Deacon <will@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/daveh/x86-mpx
Pull x86 MPX removal from Dave Hansen:
"MPX requires recompiling applications, which requires compiler
support. Unfortunately, GCC 9.1 is expected to be be released without
support for MPX. This means that there was only a relatively small
window where folks could have ever used MPX. It failed to gain wide
adoption in the industry, and Linux was the only mainstream OS to ever
support it widely.
Support for the feature may also disappear on future processors.
This set completes the process that we started during the 5.4 merge
window when the MPX prctl()s were removed. XSAVE support is left in
place, which allows MPX-using KVM guests to continue to function"
* tag 'mpx-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/daveh/x86-mpx:
x86/mpx: remove MPX from arch/x86
mm: remove arch_bprm_mm_init() hook
x86/mpx: remove bounds exception code
x86/mpx: remove build infrastructure
x86/alternatives: add missing insn.h include
|
|
From: Dave Hansen <dave.hansen@linux.intel.com>
MPX is being removed from the kernel due to a lack of support
in the toolchain going forward (gcc).
arch_bprm_mm_init() is used at execve() time. The only non-stub
implementation is on x86 for MPX. Remove the hook entirely from
all architectures and generic code.
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: x86@kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Ingo Molnar:
"The main changes in the timer code in this cycle were:
- Clockevent updates:
- timer-of framework cleanups. (Geert Uytterhoeven)
- Use timer-of for the renesas-ostm and the device name to prevent
name collision in case of multiple timers. (Geert Uytterhoeven)
- Check if there is an error after calling of_clk_get in asm9260
(Chuhong Yuan)
- ABI fix: Zero out high order bits of nanoseconds on compat
syscalls. This got broken a year ago, with apparently no side
effects so far.
Since the kernel would use random data otherwise I don't think we'd
have other options but to fix the bug, even if there was a side
effect to applications (Dmitry Safonov)
- Optimize ns_to_timespec64() on 32-bit systems: move away from
div_s64_rem() which can be slow, to div_u64_rem() which is faster
(Arnd Bergmann)
- Annotate KCSAN-reported false positive data races in
hrtimer_is_queued() users by moving timer->state handling over to
the READ_ONCE()/WRITE_ONCE() APIs. This documents these accesses
(Eric Dumazet)
- Misc cleanups and small fixes"
[ I undid the "ABI fix" and updated the comments instead. The reason
there were apparently no side effects is that the fix was a no-op.
The updated comment is to say _why_ it was a no-op. - Linus ]
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time: Zero the upper 32-bits in __kernel_timespec on 32-bit
time: Rename tsk->real_start_time to ->start_boottime
hrtimer: Remove the comment about not used HRTIMER_SOFTIRQ
time: Fix spelling mistake in comment
time: Optimize ns_to_timespec64()
hrtimer: Annotate lockless access to timer->state
clocksource/drivers/asm9260: Add a check for of_clk_get
clocksource/drivers/renesas-ostm: Use unique device name instead of ostm
clocksource/drivers/renesas-ostm: Convert to timer_of
clocksource/drivers/timer-of: Use unique device name instead of timer
clocksource/drivers/timer-of: Convert last full_name to %pOF
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull pipe rework from David Howells:
"This is my set of preparatory patches for building a general
notification queue on top of pipes. It makes a number of significant
changes:
- It removes the nr_exclusive argument from __wake_up_sync_key() as
this is always 1. This prepares for the next step:
- Adds wake_up_interruptible_sync_poll_locked() so that poll can be
woken up from a function that's holding the poll waitqueue
spinlock.
- Change the pipe buffer ring to be managed in terms of unbounded
head and tail indices rather than bounded index and length. This
means that reading the pipe only needs to modify one index, not
two.
- A selection of helper functions are provided to query the state of
the pipe buffer, plus a couple to apply updates to the pipe
indices.
- The pipe ring is allowed to have kernel-reserved slots. This allows
many notification messages to be spliced in by the kernel without
allowing userspace to pin too many pages if it writes to the same
pipe.
- Advance the head and tail indices inside the pipe waitqueue lock
and use wake_up_interruptible_sync_poll_locked() to poke poll
without having to take the lock twice.
- Rearrange pipe_write() to preallocate the buffer it is going to
write into and then drop the spinlock. This allows kernel
notifications to then be added the ring whilst it is filling the
buffer it allocated. The read side is stalled because the pipe
mutex is still held.
- Don't wake up readers on a pipe if there was already data in it
when we added more.
- Don't wake up writers on a pipe if the ring wasn't full before we
removed a buffer"
* tag 'notifications-pipe-prep-20191115' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
pipe: Remove sync on wake_ups
pipe: Increase the writer-wakeup threshold to reduce context-switch count
pipe: Check for ring full inside of the spinlock in pipe_write()
pipe: Remove redundant wakeup from pipe_write()
pipe: Rearrange sequence in pipe_write() to preallocate slot
pipe: Conditionalise wakeup in pipe_read()
pipe: Advance tail pointer inside of wait spinlock in pipe_read()
pipe: Allow pipes to have kernel-reserved slots
pipe: Use head and tail pointers for the ring, not cursor and length
Add wake_up_interruptible_sync_poll_locked()
Remove the nr_exclusive argument from __wake_up_sync_key()
pipe: Reduce #inclusion of pipe_fs_i.h
|
|
mm_release() contains the futex exit handling. mm_release() is called from
do_exit()->exit_mm() and from exec()->exec_mm().
In the exit_mm() case PF_EXITING and the futex state is updated. In the
exec_mm() case these states are not touched.
As the futex exit code needs further protections against exit races, this
needs to be split into two functions.
Preparatory only, no functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191106224556.240518241@linutronix.de
|
|
Since it stores CLOCK_BOOTTIME, not, as the name suggests,
CLOCK_REALTIME, let's rename ->real_start_time to ->start_bootime.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Remove some #inclusions of linux/pipe_fs_i.h that don't seem to be
necessary any more.
Signed-off-by: David Howells <dhowells@redhat.com>
|
|
The membarrier_state field is located within the mm_struct, which
is not guaranteed to exist when used from runqueue-lock-free iteration
on runqueues by the membarrier system call.
Copy the membarrier_state from the mm_struct into the scheduler runqueue
when the scheduler switches between mm.
When registering membarrier for mm, after setting the registration bit
in the mm membarrier state, issue a synchronize_rcu() to ensure the
scheduler observes the change. In order to take care of the case
where a runqueue keeps executing the target mm without swapping to
other mm, iterate over each runqueue and issue an IPI to copy the
membarrier_state from the mm_struct into each runqueue which have the
same mm which state has just been modified.
Move the mm membarrier_state field closer to pgd in mm_struct to use
a cache line already touched by the scheduler switch_mm.
The membarrier_execve() (now membarrier_exec_mmap) hook now needs to
clear the runqueue's membarrier state in addition to clear the mm
membarrier state, so move its implementation into the scheduler
membarrier code so it can access the runqueue structure.
Add memory barrier in membarrier_exec_mmap() prior to clearing
the membarrier state, ensuring memory accesses executed prior to exec
are not reordered with the stores clearing the membarrier state.
As suggested by Linus, move all membarrier.c RCU read-side locks outside
of the for each cpu loops.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190919173705.2181-5-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
When going through execve(), zero out the NUMA fault statistics instead of
freeing them.
During execve, the task is reachable through procfs and the scheduler. A
concurrent /proc/*/sched reader can read data from a freed ->numa_faults
allocation (confirmed by KASAN) and write it back to userspace.
I believe that it would also be possible for a use-after-free read to occur
through a race between a NUMA fault and execve(): task_numa_fault() can
lead to task_numa_compare(), which invokes task_weight() on the currently
running task of a different CPU.
Another way to fix this would be to make ->numa_faults RCU-managed or add
extra locking, but it seems easier to wipe the NUMA fault statistics on
execve.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Fixes: 82727018b0d3 ("sched/numa: Call task_numa_free() from do_execve()")
Link: https://lkml.kernel.org/r/20190716152047.14424-1-jannh@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull force_sig() argument change from Eric Biederman:
"A source of error over the years has been that force_sig has taken a
task parameter when it is only safe to use force_sig with the current
task.
The force_sig function is built for delivering synchronous signals
such as SIGSEGV where the userspace application caused a synchronous
fault (such as a page fault) and the kernel responded with a signal.
Because the name force_sig does not make this clear, and because the
force_sig takes a task parameter the function force_sig has been
abused for sending other kinds of signals over the years. Slowly those
have been fixed when the oopses have been tracked down.
This set of changes fixes the remaining abusers of force_sig and
carefully rips out the task parameter from force_sig and friends
making this kind of error almost impossible in the future"
* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits)
signal/x86: Move tsk inside of CONFIG_MEMORY_FAILURE in do_sigbus
signal: Remove the signal number and task parameters from force_sig_info
signal: Factor force_sig_info_to_task out of force_sig_info
signal: Generate the siginfo in force_sig
signal: Move the computation of force into send_signal and correct it.
signal: Properly set TRACE_SIGNAL_LOSE_INFO in __send_signal
signal: Remove the task parameter from force_sig_fault
signal: Use force_sig_fault_to_task for the two calls that don't deliver to current
signal: Explicitly call force_sig_fault on current
signal/unicore32: Remove tsk parameter from __do_user_fault
signal/arm: Remove tsk parameter from __do_user_fault
signal/arm: Remove tsk parameter from ptrace_break
signal/nds32: Remove tsk parameter from send_sigtrap
signal/riscv: Remove tsk parameter from do_trap
signal/sh: Remove tsk parameter from force_sig_info_fault
signal/um: Remove task parameter from send_sigtrap
signal/x86: Remove task parameter from send_sigtrap
signal: Remove task parameter from force_sig_mceerr
signal: Remove task parameter from force_sig
signal: Remove task parameter from force_sigsegv
...
|
|
The function force_sigsegv is always called on the current task
so passing in current is redundant and not passing in current
makes this fact obvious.
This also makes it clear force_sigsegv always calls force_sig
on the current task.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Add SPDX license identifiers to all files which:
- Have no license information of any form
- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the file
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
