From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E169DC282DA for ; Sun, 3 Feb 2019 14:31:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AB16D2073D for ; Sun, 3 Feb 2019 14:31:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730109AbfBCObB (ORCPT ); Sun, 3 Feb 2019 09:31:01 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:55286 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729388AbfBCOUG (ORCPT ); Sun, 3 Feb 2019 09:20:06 -0500 Received: from cable-78.29.236.164.coditel.net ([78.29.236.164] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gqIcu-00069G-AZ; Sun, 03 Feb 2019 14:20:04 +0000 Received: from ben by deadeye with local (Exim 4.92-RC4) (envelope-from ) id 1gqI9h-0007D9-Pp; Sun, 03 Feb 2019 14:49:53 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Guillaume Nault" , "David S. Miller" , "Xin Long" , "Jianlin Shi" Date: Sun, 03 Feb 2019 14:45:08 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 203/305] l2tp: fix a sock refcnt leak in l2tp_tunnel_register In-Reply-To: X-SA-Exim-Connect-IP: 78.29.236.164 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.63-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Xin Long commit f8504f4ca0a0e9f84546ef86e00b24d2ea9a0bd2 upstream. This issue happens when trying to add an existent tunnel. It doesn't call sock_put() before returning -EEXIST to release the sock refcnt that was held by calling sock_hold() before the existence check. This patch is to fix it by holding the sock after doing the existence check. Fixes: f6cd651b056f ("l2tp: fix race in duplicate tunnel detection") Reported-by: Jianlin Shi Signed-off-by: Xin Long Reviewed-by: Guillaume Nault Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/l2tp/l2tp_core.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1627,12 +1627,7 @@ int l2tp_tunnel_register(struct l2tp_tun goto err_sock; } - sk = sock->sk; - - sock_hold(sk); - tunnel->sock = sk; tunnel->l2tp_net = net; - pn = l2tp_pernet(net); spin_lock_bh(&pn->l2tp_tunnel_list_lock); @@ -1647,6 +1642,10 @@ int l2tp_tunnel_register(struct l2tp_tun list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list); spin_unlock_bh(&pn->l2tp_tunnel_list_lock); + sk = sock->sk; + sock_hold(sk); + tunnel->sock = sk; + if (tunnel->encap == L2TP_ENCAPTYPE_UDP) { udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP; udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;