Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422928AbaDKQJb (ORCPT ); Fri, 11 Apr 2014 12:09:31 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:56306 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754288AbaDKQH3 (ORCPT ); Fri, 11 Apr 2014 12:07:29 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Stancek , =?UTF-8?q?Linus=20L=C3=BCssing?= , Hannes Frederic Sowa , "David S. Miller" Subject: [PATCH 3.10 09/41] bridge: multicast: add sanity check for query source addresses Date: Fri, 11 Apr 2014 09:09:40 -0700 Message-Id: <20140411160933.509041367@linuxfoundation.org> X-Mailer: git-send-email 1.9.0 In-Reply-To: <20140411160932.865173041@linuxfoundation.org> References: <20140411160932.865173041@linuxfoundation.org> User-Agent: quilt/0.60-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: =?UTF-8?q?Linus=20L=C3=BCssing?= [ Upstream commit 6565b9eeef194afbb3beec80d6dd2447f4091f8c ] MLD queries are supposed to have an IPv6 link-local source address according to RFC2710, section 4 and RFC3810, section 5.1.14. This patch adds a sanity check to ignore such broken MLD queries. Without this check, such malformed MLD queries can result in a denial of service: The queries are ignored by any MLD listener therefore they will not respond with an MLD report. However, without this patch these malformed MLD queries would enable the snooping part in the bridge code, potentially shutting down the according ports towards these hosts for multicast traffic as the bridge did not learn about these listeners. Reported-by: Jan Stancek Signed-off-by: Linus Lüssing Reviewed-by: Hannes Frederic Sowa Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/bridge/br_multicast.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -1176,6 +1176,12 @@ static int br_ip6_multicast_query(struct br_multicast_query_received(br, port, !ipv6_addr_any(&ip6h->saddr)); + /* RFC2710+RFC3810 (MLDv1+MLDv2) require link-local source addresses */ + if (!(ipv6_addr_type(&ip6h->saddr) & IPV6_ADDR_LINKLOCAL)) { + err = -EINVAL; + goto out; + } + if (skb->len == sizeof(*mld)) { if (!pskb_may_pull(skb, sizeof(*mld))) { err = -EINVAL; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/