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,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 F311CC43457 for ; Sun, 18 Oct 2020 19:59:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C25B822269 for ; Sun, 18 Oct 2020 19:59:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603051156; bh=d1Lr4GehX4dE3kIk5kxyDTMVA52mPqEtJ0L3Pwyw6a4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=eR8WUnVNYYs5PuPE+kqJlKIFm9PbybbBgG9vT0Uu7CmgKmy06Qmw6AwnFMny4bYtD u1WCR6pD0t47844YRZ+TEj+mYR0W2JRNt8P2DxIsu83w9rKNB/JB3GCwLeq0doFzSL F88T4YDaFgvCkHQWXEBZcSws/nnZPIa6waTu/Y3U= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727917AbgJRTSy (ORCPT ); Sun, 18 Oct 2020 15:18:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:57124 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727719AbgJRTSv (ORCPT ); Sun, 18 Oct 2020 15:18:51 -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 2B9C42231B; Sun, 18 Oct 2020 19:18:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603048730; bh=d1Lr4GehX4dE3kIk5kxyDTMVA52mPqEtJ0L3Pwyw6a4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xLWOlYLGVVB7Ekmw9Ml0rryAYG0qiauFL/mGUM77YBQkekhao6bKc4YM96svrAdfc XRnyNvxOzq5ZIDvomrGU33WvtPwQlJtFa05dDz6QQ5y6eaKuEhwfPsNF1m7uQV/w3h Hwee1mARjaUJ6fpXQoEeE6cHHSv17pB/Gc+6oOWU= 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 5.9 035/111] ipv6/icmp: l3mdev: Perform icmp error route lookup on source device routing table (v2) Date: Sun, 18 Oct 2020 15:16:51 -0400 Message-Id: <20201018191807.4052726-35-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201018191807.4052726-1-sashal@kernel.org> References: <20201018191807.4052726-1-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 a4e4912ad607b..91209a2760aa5 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -501,8 +501,11 @@ 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 c78e67d7747fb..cd623068de536 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -468,8 +468,6 @@ 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