From: David Howells <dhowells@xxxxxxxxxx>
[ 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@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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;
--
2.27.0
