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+3a030a73b6c1e9833...@syzkaller.appspotmail.com Signed-off-by: Bharath Vedartham <linux.b...@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
