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=-7.1 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 685E9C2F3BE for ; Mon, 21 Jan 2019 13:54:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3306C20861 for ; Mon, 21 Jan 2019 13:54:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548078888; bh=ZQhGRtDpuesN0sA/366nsdg5qRo2HoObkw6sQC6lN6c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=FgwRf97e/+MvEfFb97emSS9M4mSG1JBYGObdJ3SkJ3oEbS8kKxBbKzF6nQRBuURxx H/7+6dmaxpG0WaeJXxIqOxmqpUCNZLcYrgcVFqzihPp0IZmfz3rRYSScg7NmZm0+uK k9WpCKW0YrbuJ9/91THh3D1HLFpp2phOklW/pZwU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731571AbfAUNyq (ORCPT ); Mon, 21 Jan 2019 08:54:46 -0500 Received: from mail.kernel.org ([198.145.29.99]:38990 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730767AbfAUNyn (ORCPT ); Mon, 21 Jan 2019 08:54:43 -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 B853520861; Mon, 21 Jan 2019 13:54:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548078882; bh=ZQhGRtDpuesN0sA/366nsdg5qRo2HoObkw6sQC6lN6c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=V19At4V8rDTU6AiccxO+P/rHgeYBI3hGYStUjT6Z1E6/iOHlqBvK7arb+1h+ANggN lvDQ7pHhMSMRERF5ckkeLveMLXGt+qpxn//LOVUFESK7JzggHjY4eF+8sck2/hvYDA ZK9bkcvKBdvFQelCtpPMmCE59c1VKVZ+QYCHTeyY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot , Eric Dumazet , Willem de Bruijn , "David S. Miller" Subject: [PATCH 4.9 17/51] ip: on queued skb use skb_header_pointer instead of pskb_may_pull Date: Mon, 21 Jan 2019 14:44:13 +0100 Message-Id: <20190121122455.115057327@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190121122453.700446926@linuxfoundation.org> References: <20190121122453.700446926@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 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Willem de Bruijn [ Upstream commit 4a06fa67c4da20148803525151845276cdb995c1 ] Commit 2efd4fca703a ("ip: in cmsg IP(V6)_ORIGDSTADDR call pskb_may_pull") avoided a read beyond the end of the skb linear segment by calling pskb_may_pull. That function can trigger a BUG_ON in pskb_expand_head if the skb is shared, which it is when when peeking. It can also return ENOMEM. Avoid both by switching to safer skb_header_pointer. Fixes: 2efd4fca703a ("ip: in cmsg IP(V6)_ORIGDSTADDR call pskb_may_pull") Reported-by: syzbot Suggested-by: Eric Dumazet Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/ip_sockglue.c | 12 +++++------- net/ipv6/datagram.c | 10 ++++------ 2 files changed, 9 insertions(+), 13 deletions(-) --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -133,19 +133,17 @@ static void ip_cmsg_recv_security(struct static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb) { + __be16 _ports[2], *ports; struct sockaddr_in sin; - __be16 *ports; - int end; - - end = skb_transport_offset(skb) + 4; - if (end > 0 && !pskb_may_pull(skb, end)) - return; /* All current transport protocols have the port numbers in the * first four bytes of the transport header and this function is * written with this assumption in mind. */ - ports = (__be16 *)skb_transport_header(skb); + ports = skb_header_pointer(skb, skb_transport_offset(skb), + sizeof(_ports), &_ports); + if (!ports) + return; sin.sin_family = AF_INET; sin.sin_addr.s_addr = ip_hdr(skb)->daddr; --- a/net/ipv6/datagram.c +++ b/net/ipv6/datagram.c @@ -695,17 +695,15 @@ void ip6_datagram_recv_specific_ctl(stru } if (np->rxopt.bits.rxorigdstaddr) { struct sockaddr_in6 sin6; - __be16 *ports; - int end; + __be16 _ports[2], *ports; - end = skb_transport_offset(skb) + 4; - if (end <= 0 || pskb_may_pull(skb, end)) { + ports = skb_header_pointer(skb, skb_transport_offset(skb), + sizeof(_ports), &_ports); + if (ports) { /* All current transport protocols have the port numbers in the * first four bytes of the transport header and this function is * written with this assumption in mind. */ - ports = (__be16 *)skb_transport_header(skb); - sin6.sin6_family = AF_INET6; sin6.sin6_addr = ipv6_hdr(skb)->daddr; sin6.sin6_port = ports[1];