diff options
| author | David Howells <dhowells@redhat.com> | 2020-12-09 00:52:03 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-09 00:59:25 +0100 |
| commit | 4cb682964706deffb4861f0a91329ab3a705039f (patch) | |
| tree | 01a8582a2b39c7d25ca8228bc784a102e2e14499 | |
| parent | Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs (diff) | |
| download | linux-4cb682964706deffb4861f0a91329ab3a705039f.tar.xz linux-4cb682964706deffb4861f0a91329ab3a705039f.zip | |
afs: Fix memory leak when mounting with multiple source parameters
There's a memory leak in afs_parse_source() whereby multiple source=
parameters overwrite fc->source in the fs_context struct without freeing
the previously recorded source.
Fix this by only permitting a single source parameter and rejecting with
an error all subsequent ones.
This was caught by syzbot with the kernel memory leak detector, showing
something like the following trace:
unreferenced object 0xffff888114375440 (size 32):
comm "repro", pid 5168, jiffies 4294923723 (age 569.948s)
backtrace:
slab_post_alloc_hook+0x42/0x79
__kmalloc_track_caller+0x125/0x16a
kmemdup_nul+0x24/0x3c
vfs_parse_fs_string+0x5a/0xa1
generic_parse_monolithic+0x9d/0xc5
do_new_mount+0x10d/0x15a
do_mount+0x5f/0x8e
__do_sys_mount+0xff/0x127
do_syscall_64+0x2d/0x3a
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: 13fcc6837049 ("afs: Add fs_context support")
Reported-by: syzbot+86dc6632faaca40133ab@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/afs/super.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/afs/super.c b/fs/afs/super.c index 6c5900df6aa5..e38bb1e7a4d2 100644 --- a/fs/afs/super.c +++ b/fs/afs/super.c @@ -230,6 +230,9 @@ static int afs_parse_source(struct fs_context *fc, struct fs_parameter *param) _enter(",%s", name); + if (fc->source) + return invalf(fc, "kAFS: Multiple sources not supported"); + if (!name) { printk(KERN_ERR "kAFS: no volume name specified\n"); return -EINVAL; |