From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752767AbcHNSHX (ORCPT ); Sun, 14 Aug 2016 14:07:23 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:54948 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750955AbcHNR7v (ORCPT ); Sun, 14 Aug 2016 13:59:51 -0400 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, "David S. Miller" , "Sven Eckelmann" , "Marek Lindner" Date: Sat, 13 Aug 2016 18:42:51 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 255/305] batman-adv: Fix ICMP RR ethernet access after skb_linearize In-Reply-To: X-SA-Exim-Connect-IP: 92.40.249.202 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.37-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Sven Eckelmann commit 3b55e4422087f9f7b241031d758a0c65584e4297 upstream. The skb_linearize may reallocate the skb. This makes the calculated pointer for ethhdr invalid. But it the pointer is used later to fill in the RR field of the batadv_icmp_packet_rr packet. Instead re-evaluate eth_hdr after the skb_linearize+skb_cow to fix the pointer and avoid the invalid read. Fixes: da6b8c20a5b8 ("batman-adv: generalize batman-adv icmp packet handling") Signed-off-by: Sven Eckelmann Signed-off-by: Marek Lindner Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/batman-adv/routing.c | 1 + 1 file changed, 1 insertion(+) --- a/net/batman-adv/routing.c +++ b/net/batman-adv/routing.c @@ -344,6 +344,7 @@ int batadv_recv_icmp_packet(struct sk_bu if (skb_cow(skb, ETH_HLEN) < 0) goto out; + ethhdr = eth_hdr(skb); icmph = (struct batadv_icmp_header *)skb->data; icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph; if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)