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=-7.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 840CFC43441 for ; Wed, 21 Nov 2018 19:07:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 41D83214DB for ; Wed, 21 Nov 2018 19:07:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="DKLL0nLq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 41D83214DB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387832AbeKVFm4 (ORCPT ); Thu, 22 Nov 2018 00:42:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:37528 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387767AbeKVFmz (ORCPT ); Thu, 22 Nov 2018 00:42:55 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9BA6F214DB; Wed, 21 Nov 2018 19:07:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1542827242; bh=QT7vzL22FBlOhQK3AgHRrgshvgpa6rBvwohncDvt6CY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DKLL0nLqPMdhEj544Ai5jTK9GH7MDrMZma9MN1juSa/AbK+43DXoPbsCTfaaqUVQn HCIShIY6v7y5pmvxuDTkQV0tdwPzamFqA8Qqm1RoKg5VC2cVm3sF2LTqSsr/47EIcH Kd22iBZqxD5nDcBtcBZk2S16/Nc6bydTNBHI1Ly8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jianlin Shi , Xin Long , Guillaume Nault , "David S. Miller" Subject: [PATCH 4.19 27/42] l2tp: fix a sock refcnt leak in l2tp_tunnel_register Date: Wed, 21 Nov 2018 20:06:03 +0100 Message-Id: <20181121183149.168507222@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181121183147.869199006@linuxfoundation.org> References: <20181121183147.869199006@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xin Long [ Upstream commit f8504f4ca0a0e9f84546ef86e00b24d2ea9a0bd2 ] 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: Greg Kroah-Hartman --- 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 @@ -1490,12 +1490,7 @@ 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); @@ -1510,6 +1505,10 @@ 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) { struct udp_tunnel_sock_cfg udp_cfg = { .sk_user_data = tunnel,