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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 1B6D1C433E0 for ; Tue, 16 Jun 2020 15:36:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE28D20C09 for ; Tue, 16 Jun 2020 15:36:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592321785; bh=f4dWbME0zvTO4lNAmFwEvgbVjHjm7e7nyr1BsvdN+HM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=KFTG7QnfyC3cG+HElFtbebW3ptYFp73YHWsYbAYIfM3JZHytpx2/dZtKs/3ZBDiFI DYUXdl9IdtSIY16fYFcSSKDbjYHMApwdfBbbd39fBbjiIA0mMAo6GD4Fvi8+jGQeWv mhvrREFoO+7n63xTgI5UUdOgblUcrhNWA7Z3YlSI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729937AbgFPPgZ (ORCPT ); Tue, 16 Jun 2020 11:36:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:46902 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729609AbgFPPgU (ORCPT ); Tue, 16 Jun 2020 11:36:20 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F080420B1F; Tue, 16 Jun 2020 15:36:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592321779; bh=f4dWbME0zvTO4lNAmFwEvgbVjHjm7e7nyr1BsvdN+HM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=D8E5EXsoDUs5W+FQ29XRa5o2BcHRC3mVRkihFmcuRmSizKsZS0ILS4zgew3vpHl3H uA/HP0457MyZRnY00a7VOGaLqAJfyKRIJ85Kj3axLfMG0coAVaM4D5bXSxZduVx4s5 UZvm9i/R/5pu0gO+W/8DcMG2vODzaODpoVdsOJgc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ido Schimmel , Alla Segal , Nikolay Aleksandrov , "David S. Miller" Subject: [PATCH 5.4 005/134] bridge: Avoid infinite loop when suppressing NS messages with invalid options Date: Tue, 16 Jun 2020 17:33:09 +0200 Message-Id: <20200616153100.917915774@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200616153100.633279950@linuxfoundation.org> References: <20200616153100.633279950@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ido Schimmel [ Upstream commit 53fc685243bd6fb90d90305cea54598b78d3cbfc ] When neighbor suppression is enabled the bridge device might reply to Neighbor Solicitation (NS) messages on behalf of remote hosts. In case the NS message includes the "Source link-layer address" option [1], the bridge device will use the specified address as the link-layer destination address in its reply. To avoid an infinite loop, break out of the options parsing loop when encountering an option with length zero and disregard the NS message. This is consistent with the IPv6 ndisc code and RFC 4886 which states that "Nodes MUST silently discard an ND packet that contains an option with length zero" [2]. [1] https://tools.ietf.org/html/rfc4861#section-4.3 [2] https://tools.ietf.org/html/rfc4861#section-4.6 Fixes: ed842faeb2bd ("bridge: suppress nd pkts on BR_NEIGH_SUPPRESS ports") Signed-off-by: Ido Schimmel Reported-by: Alla Segal Tested-by: Alla Segal Acked-by: Nikolay Aleksandrov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/bridge/br_arp_nd_proxy.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/net/bridge/br_arp_nd_proxy.c +++ b/net/bridge/br_arp_nd_proxy.c @@ -276,6 +276,10 @@ static void br_nd_send(struct net_bridge ns_olen = request->len - (skb_network_offset(request) + sizeof(struct ipv6hdr)) - sizeof(*ns); for (i = 0; i < ns_olen - 1; i += (ns->opt[i + 1] << 3)) { + if (!ns->opt[i + 1]) { + kfree_skb(reply); + return; + } if (ns->opt[i] == ND_OPT_SOURCE_LL_ADDR) { daddr = ns->opt + i + sizeof(struct nd_opt_hdr); break;