From: David Howells dhowells@redhat.com
[ Upstream commit 4cb682964706deffb4861f0a91329ab3a705039f ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- fs/afs/super.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/fs/afs/super.c b/fs/afs/super.c index 7f8a9b3137bff..eb04dcc543289 100644 --- a/fs/afs/super.c +++ b/fs/afs/super.c @@ -236,6 +236,9 @@ 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;