Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751551AbeAAOnP (ORCPT + 1 other); Mon, 1 Jan 2018 09:43:15 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:46156 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932249AbeAAOnN (ORCPT ); Mon, 1 Jan 2018 09:43:13 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mohamed Ghannam , Eric Dumazet , "David S. Miller" Subject: [PATCH 4.14 077/146] net: ipv4: fix for a race condition in raw_sendmsg Date: Mon, 1 Jan 2018 15:37:48 +0100 Message-Id: <20180101140135.251717455@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20180101140123.743014891@linuxfoundation.org> References: <20180101140123.743014891@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mohamed Ghannam [ Upstream commit 8f659a03a0ba9289b9aeb9b4470e6fb263d6f483 ] inet->hdrincl is racy, and could lead to uninitialized stack pointer usage, so its value should be read only once. Fixes: c008ba5bdc9f ("ipv4: Avoid reading user iov twice after raw_probe_proto_opt") Signed-off-by: Mohamed Ghannam Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/raw.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) --- a/net/ipv4/raw.c +++ b/net/ipv4/raw.c @@ -513,11 +513,16 @@ static int raw_sendmsg(struct sock *sk, int err; struct ip_options_data opt_copy; struct raw_frag_vec rfv; + int hdrincl; err = -EMSGSIZE; if (len > 0xFFFF) goto out; + /* hdrincl should be READ_ONCE(inet->hdrincl) + * but READ_ONCE() doesn't work with bit fields + */ + hdrincl = inet->hdrincl; /* * Check the flags. */ @@ -593,7 +598,7 @@ static int raw_sendmsg(struct sock *sk, /* Linux does not mangle headers on raw sockets, * so that IP options + IP_HDRINCL is non-sense. */ - if (inet->hdrincl) + if (hdrincl) goto done; if (ipc.opt->opt.srr) { if (!daddr) @@ -615,12 +620,12 @@ static int raw_sendmsg(struct sock *sk, flowi4_init_output(&fl4, ipc.oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE, - inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol, + hdrincl ? IPPROTO_RAW : sk->sk_protocol, inet_sk_flowi_flags(sk) | - (inet->hdrincl ? FLOWI_FLAG_KNOWN_NH : 0), + (hdrincl ? FLOWI_FLAG_KNOWN_NH : 0), daddr, saddr, 0, 0, sk->sk_uid); - if (!inet->hdrincl) { + if (!hdrincl) { rfv.msg = msg; rfv.hlen = 0; @@ -645,7 +650,7 @@ static int raw_sendmsg(struct sock *sk, goto do_confirm; back_from_confirm: - if (inet->hdrincl) + if (hdrincl) err = raw_send_hdrinc(sk, &fl4, msg, len, &rt, msg->msg_flags, &ipc.sockc);