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authorKees Cook <keescook@chromium.org>2024-01-24 11:15:33 -0800
committerKees Cook <keescook@chromium.org>2024-01-24 11:48:52 -0800
commit90383cc07895183c75a0db2460301c2ffd912359 (patch)
treeca41f9d32f052e063b48e864ac60171b55c300b5
parent84c39ec57d409e803a9bb6e4e85daf1243e0e80b (diff)
downloadlinux-90383cc07895183c75a0db2460301c2ffd912359.tar.gz
exec: Distinguish in_execve from in_exec
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>
-rw-r--r--fs/exec.c1
-rw-r--r--include/linux/sched.h2
-rw-r--r--kernel/fork.c1
3 files changed, 3 insertions, 1 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 39d773021fffd5..d179abb78a1c81 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1633,6 +1633,7 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
}
rcu_read_unlock();
+ /* "users" and "in_exec" locked for copy_fs() */
if (p->fs->users > n_fs)
bprm->unsafe |= LSM_UNSAFE_SHARE;
else
diff --git a/include/linux/sched.h b/include/linux/sched.h
index cdb8ea53c365ba..ffe8f618ab8697 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -920,7 +920,7 @@ struct task_struct {
unsigned sched_rt_mutex:1;
#endif
- /* Bit to tell LSMs we're in execve(): */
+ /* Bit to tell TOMOYO we're in execve(): */
unsigned in_execve:1;
unsigned in_iowait:1;
#ifndef TIF_RESTORE_SIGMASK
diff --git a/kernel/fork.c b/kernel/fork.c
index 47ff3b35352e0b..0d944e92a43ffa 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1748,6 +1748,7 @@ static int copy_fs(unsigned long clone_flags, struct task_struct *tsk)
if (clone_flags & CLONE_FS) {
/* tsk->fs is already what we want */
spin_lock(&fs->lock);
+ /* "users" and "in_exec" locked for check_unsafe_exec() */
if (fs->in_exec) {
spin_unlock(&fs->lock);
return -EAGAIN;