From patchwork Wed Dec 9 09:37:45 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 554354 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 57C941402CD; Wed, 9 Dec 2015 20:41:27 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1a6bFU-0002ds-S1; Wed, 09 Dec 2015 09:41:24 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1a6bFN-0002a2-KD for kernel-team@lists.ubuntu.com; Wed, 09 Dec 2015 09:41:17 +0000 Received: from 1.general.henrix.uk.vpn ([10.172.192.212] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1a6bFN-0007rm-98; Wed, 09 Dec 2015 09:41:17 +0000 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.16.y-ckt 095/126] packet: fix match_fanout_group() Date: Wed, 9 Dec 2015 09:37:45 +0000 Message-Id: <1449653896-5236-96-git-send-email-luis.henriques@canonical.com> In-Reply-To: <1449653896-5236-1-git-send-email-luis.henriques@canonical.com> References: <1449653896-5236-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Cc: Eric Leblond , Eric Dumazet , Willem de Bruijn , "David S. Miller" X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.16.7-ckt21 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet commit 161642e24fee40fba2c5bc2ceacc00d118a22d65 upstream. Recent TCP listener patches exposed a prior af_packet bug : match_fanout_group() blindly assumes it is always safe to cast sk to a packet socket to compare fanout with af_packet_priv But SYNACK packets can be sent while attached to request_sock, which are smaller than a "struct sock". We can read non existent memory and crash. Fixes: c0de08d04215 ("af_packet: don't emit packet on orig fanout group") Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener") Signed-off-by: Eric Dumazet Cc: Willem de Bruijn Cc: Eric Leblond Signed-off-by: David S. Miller Signed-off-by: Luis Henriques --- net/packet/af_packet.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index e6bd6df9e2a2..1f618bbce0ac 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -1412,10 +1412,10 @@ static void __fanout_unlink(struct sock *sk, struct packet_sock *po) static bool match_fanout_group(struct packet_type *ptype, struct sock *sk) { - if (ptype->af_packet_priv == (void *)((struct packet_sock *)sk)->fanout) - return true; + if (sk->sk_family != PF_PACKET) + return false; - return false; + return ptype->af_packet_priv == pkt_sk(sk)->fanout; } static int fanout_add(struct sock *sk, u16 id, u16 type_flags)