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 36917C2F3BE for ; Mon, 21 Jan 2019 13:47:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 01E9220861 for ; Mon, 21 Jan 2019 13:47:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548078437; bh=bo6k+wST40FkNPu9W0kvdK1RM/2gcF5jL9w/l8nJil0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=XkTfvrOGLjESu0cQOF0oCILttrcrgKJrBTz51PoCfMFf7M1kUxfnpwiOWmvxHdv+l oN5QJh9w6e4NcQ3MM+DgggHoP50Fr3Y9cI+/HRw9K2+zhz9/kAC801HGflW8FRP05h gAsJMrY8T2gVYUs+E4/sqhOWNoWPOQ5Z64ZsLHYw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729530AbfAUNrQ (ORCPT ); Mon, 21 Jan 2019 08:47:16 -0500 Received: from mail.kernel.org ([198.145.29.99]:56414 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729514AbfAUNrN (ORCPT ); Mon, 21 Jan 2019 08:47:13 -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 B1B4320879; Mon, 21 Jan 2019 13:47:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548078432; bh=bo6k+wST40FkNPu9W0kvdK1RM/2gcF5jL9w/l8nJil0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1UFAltA8wxtm+GJjZp+o74bPLa9oIthsZIS/mMoG29hpKoi7S6VxUYSNzoK6lMZPV b8DbU3YIdL8csw+ShhRvfmcs7VSxdXSuNN1xoRAjmHIDfmlMdAmwADrUeJb2o+HK2z SWv2chBTS6cgERuTa1SXKUClXbrXevzCn+o0mcR4= 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 4.20 029/111] ip: on queued skb use skb_header_pointer instead of pskb_may_pull Date: Mon, 21 Jan 2019 14:42:23 +0100 Message-Id: <20190121122459.045789194@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190121122455.819406896@linuxfoundation.org> References: <20190121122455.819406896@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: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.20-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 @@ -148,19 +148,17 @@ 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 @@ -701,17 +701,15 @@ 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];