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=-6.0 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 6C56BC43381 for ; Fri, 22 Mar 2019 11:24:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 39C9E218B0 for ; Fri, 22 Mar 2019 11:24:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553253881; bh=MW9UEjgjQp2JunpCMRk/4++U5o+8k0u93p/XteIpvgk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jx19QHYu5xOTpj8rbtvlEmKHk2KoLgbbgGs8jT4P4SAJqZtp9ox/ZuNV8eCNILBfT 0DhLzj+wqujYERTG+OQEj9/TAri5TrpCVt5kT7RtvlZU9CdotPcGV6Vp8SeCo+hXgF dWpW37WhrL67QY0SiGWZBjO1UCAqcjP/2cI7Opik= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729166AbfCVLYj (ORCPT ); Fri, 22 Mar 2019 07:24:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:51716 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729146AbfCVLYi (ORCPT ); Fri, 22 Mar 2019 07:24:38 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.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 26FC8218B0; Fri, 22 Mar 2019 11:24:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553253877; bh=MW9UEjgjQp2JunpCMRk/4++U5o+8k0u93p/XteIpvgk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Cs6wL/Pw5HzZpBG3ZYVcv3XbYiCsH9BnjUnPd+Nnc5+GI9Dyypfo+oWi19GLmwYhh vCyhY1YlbQZr61nF2u1aBZWeZIfnCwo4Z/llM/006SvizM6ft2bgvJ/mDWmJFQpMGV +ZIuko9A8AkLh1GMyBq6mboGEtf/ya197zah6bRE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Xiumei Mu , Xin Long , "David S. Miller" Subject: [PATCH 3.18 084/134] pptp: dst_release sk_dst_cache in pptp_sock_destruct Date: Fri, 22 Mar 2019 12:14:57 +0100 Message-Id: <20190322111216.195203788@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190322111210.465931067@linuxfoundation.org> References: <20190322111210.465931067@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore 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 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xin Long [ Upstream commit 9417d81f4f8adfe20a12dd1fadf73a618cbd945d ] sk_setup_caps() is called to set sk->sk_dst_cache in pptp_connect, so we have to dst_release(sk->sk_dst_cache) in pptp_sock_destruct, otherwise, the dst refcnt will leak. It can be reproduced by this syz log: r1 = socket$pptp(0x18, 0x1, 0x2) bind$pptp(r1, &(0x7f0000000100)={0x18, 0x2, {0x0, @local}}, 0x1e) connect$pptp(r1, &(0x7f0000000000)={0x18, 0x2, {0x3, @remote}}, 0x1e) Consecutive dmesg warnings will occur: unregister_netdevice: waiting for lo to become free. Usage count = 1 v1->v2: - use rcu_dereference_protected() instead of rcu_dereference_check(), as suggested by Eric. Fixes: 00959ade36ac ("PPTP: PPP over IPv4 (Point-to-Point Tunneling Protocol)") Reported-by: Xiumei Mu Signed-off-by: Xin Long Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/ppp/pptp.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/net/ppp/pptp.c +++ b/drivers/net/ppp/pptp.c @@ -564,6 +564,7 @@ static void pptp_sock_destruct(struct so pppox_unbind_sock(sk); } skb_queue_purge(&sk->sk_receive_queue); + dst_release(rcu_dereference_protected(sk->sk_dst_cache, 1)); } static int pptp_create(struct net *net, struct socket *sock)