phonet: refcount leak in pep_sock_accep

mainline inclusion
from mainline-v5.16-rc6
commit bcd0f933
category: bugfix
bugzilla: NA
CVE: CVE-2021-45095

--------------------------------

sock_hold(sk) is invoked in pep_sock_accept(), but __sock_put(sk) is not
invoked in subsequent failure branches(pep_accept_conn() != 0).
Signed-off-by: NHangyu Hua <hbh25y@gmail.com>
Link: https://lore.kernel.org/r/20211209082839.33985-1-hbh25y@gmail.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: NYue Haibing <yuehaibing@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

net/phonet/pep.c

@@ -881,6 +881,7 @@ static struct sock *pep_sock_accept(struct sock *sk, int flags, int *errp,
 
 	err = pep_accept_conn(newsk, skb);
 	if (err) {
+		__sock_put(sk);
 		sock_put(newsk);
 		newsk = NULL;
 		goto drop;