diff options
author | Jann Horn <jannh@google.com> | 2018-08-21 21:59:37 -0700 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-08-28 07:21:37 +0200 |
commit | 88f8dcdb69e35da54b5b7579403d365df457f093 (patch) | |
tree | 167db54e95204e1c236862d8897e89c0077eed5d | |
parent | 3311a3935f86e0b28cf0884b18cd26d5b6d88bc3 (diff) | |
download | linux-88f8dcdb69e35da54b5b7579403d365df457f093.tar.gz |
reiserfs: fix broken xattr handling (heap corruption, bad retval)
commit a13f085d111e90469faf2d9965eb39b11c114d7e upstream.
This fixes the following issues:
- When a buffer size is supplied to reiserfs_listxattr() such that each
individual name fits, but the concatenation of all names doesn't fit,
reiserfs_listxattr() overflows the supplied buffer. This leads to a
kernel heap overflow (verified using KASAN) followed by an out-of-bounds
usercopy and is therefore a security bug.
- When a buffer size is supplied to reiserfs_listxattr() such that a
name doesn't fit, -ERANGE should be returned. But reiserfs instead just
truncates the list of names; I have verified that if the only xattr on a
file has a longer name than the supplied buffer length, listxattr()
incorrectly returns zero.
With my patch applied, -ERANGE is returned in both cases and the memory
corruption doesn't happen anymore.
Credit for making me clean this code up a bit goes to Al Viro, who pointed
out that the ->actor calling convention is suboptimal and should be
changed.
Link: http://lkml.kernel.org/r/20180802151539.5373-1-jannh@google.com
Fixes: 48b32a3553a5 ("reiserfs: use generic xattr handlers")
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Jeff Mahoney <jeffm@suse.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | fs/reiserfs/xattr.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c index 7c36898af40266..59b29acb6419a9 100644 --- a/fs/reiserfs/xattr.c +++ b/fs/reiserfs/xattr.c @@ -842,8 +842,10 @@ static int listxattr_filler(void *buf, const char *name, int namelen, size = handler->list(b->dentry, b->buf + b->pos, b->size, name, namelen, handler->flags); - if (size > b->size) + if (b->pos + size > b->size) { + b->pos = -ERANGE; return -ERANGE; + } } else { size = handler->list(b->dentry, NULL, 0, name, namelen, handler->flags); |