Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755691AbaDPKce (ORCPT ); Wed, 16 Apr 2014 06:32:34 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:51653 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755646AbaDPKcZ (ORCPT ); Wed, 16 Apr 2014 06:32:25 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: =?UTF-8?q?Linus=20L=C3=BCssing?= , "David S. Miller" , Luis Henriques Subject: [PATCH 3.11 12/46] bridge: multicast: add sanity check for query source addresses Date: Wed, 16 Apr 2014 11:31:28 +0100 Message-Id: <1397644322-13905-13-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1397644322-13905-1-git-send-email-luis.henriques@canonical.com> References: <1397644322-13905-1-git-send-email-luis.henriques@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Extended-Stable: 3.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.11.10.8 -stable review patch. If anyone has any objections, please let me know. ------------------ From: =?UTF-8?q?Linus=20L=C3=BCssing?= commit 6565b9eeef194afbb3beec80d6dd2447f4091f8c upstream. 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: Luis Henriques --- net/bridge/br_multicast.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index b02fb47..29ff042 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -1237,6 +1237,12 @@ static int br_ip6_multicast_query(struct net_bridge *br, (port && port->state == BR_STATE_DISABLED)) goto out; + /* 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; -- 1.9.1 -- 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/