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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 4D41BC433E7 for ; Sun, 18 Oct 2020 19:27:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 150BE222C8 for ; Sun, 18 Oct 2020 19:27:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603049222; bh=COfRaJvg2+7dBYzSg/KrRKhuupG/VpnFOn0SDm05v24=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=xTH1pyfUVoUDSIDNrNbYiXQjEvMg2VudZLhJAlXVZCMZr4PhSKY9caA0HP03/kpne r7IkWnTGCQxW/XqmzmsQqooBLOzNGo0SlMdKSQgW7M0jwb44qR+LiDqpgJGrSe7MFL iDewCDKkiU4+alRIsbWN0EU1Atln9K0kIEwIkY4w= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731830AbgJRT1A (ORCPT ); Sun, 18 Oct 2020 15:27:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:38838 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730899AbgJRTYo (ORCPT ); Sun, 18 Oct 2020 15:24:44 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8CA84222E9; Sun, 18 Oct 2020 19:24:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603049084; bh=COfRaJvg2+7dBYzSg/KrRKhuupG/VpnFOn0SDm05v24=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LhbsUqk3G/5mVRdIjgh2ar+/R3Ej9PmTf8Xo2tCY1gVJrhT8TEr2F0gM3pezka4q/ jHDhR9s5OV8iixqbvqgLn5TbkxSphyIKzSHiUnQjbD7HgZ+h3YokIdVWW0mom7Nzdf DX77yklWJ01o+CEeJBjf0GmuVMDQoYl2SkpD+CAQ= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Mathieu Desnoyers , David Ahern , Jakub Kicinski , Sasha Levin , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 21/56] ipv6/icmp: l3mdev: Perform icmp error route lookup on source device routing table (v2) Date: Sun, 18 Oct 2020 15:23:42 -0400 Message-Id: <20201018192417.4055228-21-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201018192417.4055228-1-sashal@kernel.org> References: <20201018192417.4055228-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mathieu Desnoyers [ Upstream commit 272928d1cdacfc3b55f605cb0e9115832ecfb20c ] As per RFC4443, the destination address field for ICMPv6 error messages is copied from the source address field of the invoking packet. In configurations with Virtual Routing and Forwarding tables, looking up which routing table to use for sending ICMPv6 error messages is currently done by using the destination net_device. If the source and destination interfaces are within separate VRFs, or one in the global routing table and the other in a VRF, looking up the source address of the invoking packet in the destination interface's routing table will fail if the destination interface's routing table contains no route to the invoking packet's source address. One observable effect of this issue is that traceroute6 does not work in the following cases: - Route leaking between global routing table and VRF - Route leaking between VRFs Use the source device routing table when sending ICMPv6 error messages. [ In the context of ipv4, it has been pointed out that a similar issue may exist with ICMP errors triggered when forwarding between network namespaces. It would be worthwhile to investigate whether ipv6 has similar issues, but is outside of the scope of this investigation. ] [ Testing shows that similar issues exist with ipv6 unreachable / fragmentation needed messages. However, investigation of this additional failure mode is beyond this investigation's scope. ] Link: https://tools.ietf.org/html/rfc4443 Signed-off-by: Mathieu Desnoyers Reviewed-by: David Ahern Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv6/icmp.c | 7 +++++-- net/ipv6/ip6_output.c | 2 -- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index 6d14cbe443f82..c1ab17df6cb84 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -480,8 +480,11 @@ static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, if (__ipv6_addr_needs_scope_id(addr_type)) { iif = icmp6_iif(skb); } else { - dst = skb_dst(skb); - iif = l3mdev_master_ifindex(dst ? dst->dev : skb->dev); + /* + * The source device is used for looking up which routing table + * to use for sending an ICMP error. + */ + iif = l3mdev_master_ifindex(skb->dev); } /* diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 22665e3638ac4..34ff37edda54a 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -450,8 +450,6 @@ int ip6_forward(struct sk_buff *skb) * check and decrement ttl */ if (hdr->hop_limit <= 1) { - /* Force OUTPUT device used as source address */ - skb->dev = dst->dev; icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0); __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); -- 2.25.1