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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 EC585C433FF for ; Sat, 10 Aug 2019 20:46:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CCFF3208C4 for ; Sat, 10 Aug 2019 20:46:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727373AbfHJUqu (ORCPT ); Sat, 10 Aug 2019 16:46:50 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:55322 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726907AbfHJUoH (ORCPT ); Sat, 10 Aug 2019 16:44:07 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hwYDd-00053s-2W; Sat, 10 Aug 2019 21:44:05 +0100 Received: from ben by deadeye with local (Exim 4.92) (envelope-from ) id 1hwYDK-0003cV-NP; Sat, 10 Aug 2019 21:43:46 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Steffen Klassert" Date: Sat, 10 Aug 2019 21:40:07 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 063/157] xfrm4: Fix uninitialized memory read in _decode_session4 In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.72-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Steffen Klassert commit 8742dc86d0c7a9628117a989c11f04a9b6b898f3 upstream. We currently don't reload pointers pointing into skb header after doing pskb_may_pull() in _decode_session4(). So in case pskb_may_pull() changed the pointers, we read from random memory. Fix this by putting all the needed infos on the stack, so that we don't need to access the header pointers after doing pskb_may_pull(). Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Steffen Klassert Signed-off-by: Ben Hutchings --- net/ipv4/xfrm4_policy.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) --- a/net/ipv4/xfrm4_policy.c +++ b/net/ipv4/xfrm4_policy.c @@ -103,7 +103,8 @@ static void _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse) { const struct iphdr *iph = ip_hdr(skb); - u8 *xprth = skb_network_header(skb) + iph->ihl * 4; + int ihl = iph->ihl; + u8 *xprth = skb_network_header(skb) + ihl * 4; struct flowi4 *fl4 = &fl->u.ip4; int oif = 0; @@ -114,6 +115,11 @@ _decode_session4(struct sk_buff *skb, st fl4->flowi4_mark = skb->mark; fl4->flowi4_oif = reverse ? skb->skb_iif : oif; + fl4->flowi4_proto = iph->protocol; + fl4->daddr = reverse ? iph->saddr : iph->daddr; + fl4->saddr = reverse ? iph->daddr : iph->saddr; + fl4->flowi4_tos = iph->tos; + if (!ip_is_fragment(iph)) { switch (iph->protocol) { case IPPROTO_UDP: @@ -125,7 +131,7 @@ _decode_session4(struct sk_buff *skb, st pskb_may_pull(skb, xprth + 4 - skb->data)) { __be16 *ports; - xprth = skb_network_header(skb) + iph->ihl * 4; + xprth = skb_network_header(skb) + ihl * 4; ports = (__be16 *)xprth; fl4->fl4_sport = ports[!!reverse]; @@ -138,7 +144,7 @@ _decode_session4(struct sk_buff *skb, st pskb_may_pull(skb, xprth + 2 - skb->data)) { u8 *icmp; - xprth = skb_network_header(skb) + iph->ihl * 4; + xprth = skb_network_header(skb) + ihl * 4; icmp = xprth; fl4->fl4_icmp_type = icmp[0]; @@ -151,7 +157,7 @@ _decode_session4(struct sk_buff *skb, st pskb_may_pull(skb, xprth + 4 - skb->data)) { __be32 *ehdr; - xprth = skb_network_header(skb) + iph->ihl * 4; + xprth = skb_network_header(skb) + ihl * 4; ehdr = (__be32 *)xprth; fl4->fl4_ipsec_spi = ehdr[0]; @@ -163,7 +169,7 @@ _decode_session4(struct sk_buff *skb, st pskb_may_pull(skb, xprth + 8 - skb->data)) { __be32 *ah_hdr; - xprth = skb_network_header(skb) + iph->ihl * 4; + xprth = skb_network_header(skb) + ihl * 4; ah_hdr = (__be32 *)xprth; fl4->fl4_ipsec_spi = ah_hdr[1]; @@ -175,7 +181,7 @@ _decode_session4(struct sk_buff *skb, st pskb_may_pull(skb, xprth + 4 - skb->data)) { __be16 *ipcomp_hdr; - xprth = skb_network_header(skb) + iph->ihl * 4; + xprth = skb_network_header(skb) + ihl * 4; ipcomp_hdr = (__be16 *)xprth; fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1])); @@ -188,7 +194,7 @@ _decode_session4(struct sk_buff *skb, st __be16 *greflags; __be32 *gre_hdr; - xprth = skb_network_header(skb) + iph->ihl * 4; + xprth = skb_network_header(skb) + ihl * 4; greflags = (__be16 *)xprth; gre_hdr = (__be32 *)xprth; @@ -205,10 +211,6 @@ _decode_session4(struct sk_buff *skb, st break; } } - fl4->flowi4_proto = iph->protocol; - fl4->daddr = reverse ? iph->saddr : iph->daddr; - fl4->saddr = reverse ? iph->daddr : iph->saddr; - fl4->flowi4_tos = iph->tos; } static inline int xfrm4_garbage_collect(struct dst_ops *ops)