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authorDavid Howells <dhowells@redhat.com>2020-12-09 02:52:03 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-09 02:59:25 +0300
commit4cb682964706deffb4861f0a91329ab3a705039f (patch)
tree01a8582a2b39c7d25ca8228bc784a102e2e14499 /fs/afs
parentc6f7e1510b872c281ff603a3108c084b6548d35c (diff)
downloadlinux-4cb682964706deffb4861f0a91329ab3a705039f.tar.xz
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>
Diffstat (limited to 'fs/afs')
-rw-r--r--fs/afs/super.c3
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;