* [PATCH v2] 9p/cache.c: Fix memory leak in v9fs_cache_session_get_cookie
@ 2019-05-22 19:45 Bharath Vedartham
2019-05-22 19:47 ` Dominique Martinet
0 siblings, 1 reply; 3+ messages in thread
From: Bharath Vedartham @ 2019-05-22 19:45 UTC (permalink / raw)
To: ericvh, asmadeus, lucho; +Cc: linux-kernel, v9fs-developer, linux.bhar
v9fs_cache_session_get_cookie assigns a random cachetag to v9ses->cachetag,
if the cachetag is not assigned previously.
v9fs_random_cachetag allocates memory to v9ses->cachetag with kmalloc and uses
scnprintf to fill it up with a cachetag.
But if scnprintf fails, v9ses->cachetag is not freed in the current
code causing a memory leak.
Fix this by freeing v9ses->cachetag it v9fs_random_cachetag fails.
This was reported by syzbot, the link to the report is below:
https://syzkaller.appspot.com/bug?id=f012bdf297a7a4c860c38a88b44fbee43fd9bbf3
Reported-by: syzbot+3a030a73b6c1e9833815@syzkaller.appspotmail.com
Signed-off-by: Bharath Vedartham <linux.bhar@gmail.com>
---
Changes since v2
- Made v9ses->cachetag NULL after freeing to avoid any
side effects.
---
fs/9p/cache.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/9p/cache.c b/fs/9p/cache.c
index 9eb3470..baf72da 100644
--- a/fs/9p/cache.c
+++ b/fs/9p/cache.c
@@ -66,6 +66,8 @@ void v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses)
if (!v9ses->cachetag) {
if (v9fs_random_cachetag(v9ses) < 0) {
v9ses->fscache = NULL;
+ kfree(v9ses->cachetag);
+ v9ses->cachetag = NULL;
return;
}
}
--
2.7.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] 9p/cache.c: Fix memory leak in v9fs_cache_session_get_cookie
2019-05-22 19:45 [PATCH v2] 9p/cache.c: Fix memory leak in v9fs_cache_session_get_cookie Bharath Vedartham
@ 2019-05-22 19:47 ` Dominique Martinet
2019-05-22 19:50 ` Bharath Vedartham
0 siblings, 1 reply; 3+ messages in thread
From: Dominique Martinet @ 2019-05-22 19:47 UTC (permalink / raw)
To: Bharath Vedartham; +Cc: ericvh, lucho, linux-kernel, v9fs-developer
Bharath Vedartham wrote on Thu, May 23, 2019:
> v9fs_cache_session_get_cookie assigns a random cachetag to v9ses->cachetag,
> if the cachetag is not assigned previously.
>
> v9fs_random_cachetag allocates memory to v9ses->cachetag with kmalloc and uses
> scnprintf to fill it up with a cachetag.
>
> But if scnprintf fails, v9ses->cachetag is not freed in the current
> code causing a memory leak.
>
> Fix this by freeing v9ses->cachetag it v9fs_random_cachetag fails.
>
> This was reported by syzbot, the link to the report is below:
> https://syzkaller.appspot.com/bug?id=f012bdf297a7a4c860c38a88b44fbee43fd9bbf3
>
> Reported-by: syzbot+3a030a73b6c1e9833815@syzkaller.appspotmail.com
> Signed-off-by: Bharath Vedartham <linux.bhar@gmail.com>
Thanks!
I'm on limited internet right now but will run tests and queue this up tomorrow
--
Dominique
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2019-05-22 19:45 [PATCH v2] 9p/cache.c: Fix memory leak in v9fs_cache_session_get_cookie Bharath Vedartham
2019-05-22 19:47 ` Dominique Martinet
2019-05-22 19:50 ` Bharath Vedartham
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