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,USER_AGENT_GIT autolearn=unavailable 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 990D0C433DF for ; Fri, 19 Jun 2020 16:30:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 66AE32100A for ; Fri, 19 Jun 2020 16:30:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592584216; bh=I/FX85UfBT6U9jsKybhzIC8feHyD/YdXxNXkjkWwris=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=krb3Uv7/4BZEt92pckzN71/lW20UG9Ha7hQTAxbrx7PqulbCWEJlm9vEj3yfAsleO lVkZSzP2/6cfDxIKzcrkbbgVpiNZapOLreTg3b6IetnBFd4aJluCT4IOFKXtgdY1MI KEtjjjgjopZ0ua2YCqp1kZoB6KaporPFUcaV5Yj8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389762AbgFSOxy (ORCPT ); Fri, 19 Jun 2020 10:53:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:48328 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389773AbgFSOxw (ORCPT ); Fri, 19 Jun 2020 10:53:52 -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 758FB21556; Fri, 19 Jun 2020 14:53:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592578432; bh=I/FX85UfBT6U9jsKybhzIC8feHyD/YdXxNXkjkWwris=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iXBfCku4viqp4H2f7qT5/xEqQ0TK6LN0Q15k0HClUZ/D4bVHuP+HCRGTEp3V2X8Z+ 2pXN5fNQqw5nO+cuEbMqnd8Aa5Q4gSOkw+/xLeZaFoUajark5uibt+/icB26O6gfDU Di3vS6QTfUlSHkYSczowsIefryZ/nMd6irJw8RHQ= 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 4.19 003/267] bridge: Avoid infinite loop when suppressing NS messages with invalid options Date: Fri, 19 Jun 2020 16:29:48 +0200 Message-Id: <20200619141649.014094153@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200619141648.840376470@linuxfoundation.org> References: <20200619141648.840376470@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 @@ -277,6 +277,10 @@ 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;