From: Bharath Vedartham <linux.bhar@xxxxxxxxx> commit 962a991c5de18452d6c429d99f3039387cf5cbb0 upstream. 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 Link: http://lkml.kernel.org/r/20190522194519.GA5313@bharath12345-Inspiron-5559 Reported-by: syzbot+3a030a73b6c1e9833815@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Bharath Vedartham <linux.bhar@xxxxxxxxx> Signed-off-by: Dominique Martinet <dominique.martinet@xxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/9p/cache.c | 2 ++ 1 file changed, 2 insertions(+) --- a/fs/9p/cache.c +++ b/fs/9p/cache.c @@ -51,6 +51,8 @@ void v9fs_cache_session_get_cookie(struc if (!v9ses->cachetag) { if (v9fs_random_cachetag(v9ses) < 0) { v9ses->fscache = NULL; + kfree(v9ses->cachetag); + v9ses->cachetag = NULL; return; } }
