From patchwork Fri Oct 27 08:16:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Antony Antony X-Patchwork-Id: 13438227 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0A45FFC04 for ; Fri, 27 Oct 2023 08:17:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from a.mx.secunet.com (a.mx.secunet.com [62.96.220.36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 68E861AA for ; Fri, 27 Oct 2023 01:17:01 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by a.mx.secunet.com (Postfix) with ESMTP id 3DAAF20758; Fri, 27 Oct 2023 10:17:00 +0200 (CEST) X-Virus-Scanned: by secunet Received: from a.mx.secunet.com ([127.0.0.1]) by localhost (a.mx.secunet.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id pYK-HQZRXMsq; Fri, 27 Oct 2023 10:16:59 +0200 (CEST) Received: from mailout1.secunet.com (mailout1.secunet.com [62.96.220.44]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by a.mx.secunet.com (Postfix) with ESMTPS id 8E142206DF; Fri, 27 Oct 2023 10:16:59 +0200 (CEST) Received: from cas-essen-02.secunet.de (unknown [10.53.40.202]) by mailout1.secunet.com (Postfix) with ESMTP id 8B72B80004A; Fri, 27 Oct 2023 10:16:59 +0200 (CEST) Received: from mbx-essen-02.secunet.de (10.53.40.198) by cas-essen-02.secunet.de (10.53.40.202) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.32; Fri, 27 Oct 2023 10:16:59 +0200 Received: from moon.secunet.de (172.18.149.1) by mbx-essen-02.secunet.de (10.53.40.198) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.32; Fri, 27 Oct 2023 10:16:59 +0200 Date: Fri, 27 Oct 2023 10:16:52 +0200 From: Antony Antony To: Steffen Klassert CC: Herbert Xu , Antony Antony , "David S. Miller" , , Jakub Kicinski , Subject: [PATCH v2 ipsec-next 2/2] xfrm: fix source address in icmp error generation from IPsec gateway Message-ID: <300c36a0644b63228cee8d0a74be0e1e81d0fe98.1698394516.git.antony.antony@secunet.com> Reply-To: References: Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: first-class Priority: normal Organization: secunet X-ClientProxiedBy: cas-essen-01.secunet.de (10.53.40.201) To mbx-essen-02.secunet.de (10.53.40.198) X-EXCLAIMER-MD-CONFIG: 2c86f778-e09b-4440-8b15-867914633a10 X-Patchwork-Delegate: kuba@kernel.org When enabling support for xfrm lookup using reverse ICMP payload, We have identified an issue where the source address of the IPv4 e.g "Destination Host Unreachable" message is incorrect. The IPv6 appear to do the right thing. Here is example of incorrect source address for ICMP error response. When sending a ping to an unreachable host, the sender would receive an ICMP unreachable response with a fake source address. Rather the address of the host that generated ICMP Unreachable message. This is confusing and incorrect. Example: ping -W 9 -w 5 -c 1 10.1.4.3 PING 10.1.4.3 (10.1.4.3) 56(84) bytes of data. >From 10.1.4.3 icmp_seq=1 Destination Host Unreachable Notice : packet has the source address of the ICMP "Unreachable host!" This issue can be traced back to commit 415b3334a21a ("icmp: Fix regression in nexthop resolution during replies.") which introduced a change that copied the source address from the ICMP payload. This commit would force to use source address from the gatway/host. The ICMP error message source address correctly set from the host. After fixing: ping -W 5 -c 1 10.1.4.3 PING 10.1.4.3 (10.1.4.3) 56(84) bytes of data. >From 10.1.3.2 icmp_seq=1 Destination Host Unreachable Here is an example to reporduce: export AB="10.1" for i in 1 2 3 4 5; do h="host${i}" ip netns add ${h} ip -netns ${h} link set lo up ip netns exec ${h} sysctl -wq net.ipv4.ip_forward=1 if [ $i -lt 5 ]; then ip -netns ${h} link add eth0 type veth peer name eth10${i} ip -netns ${h} addr add "${AB}.${i}.1/24" dev eth0 ip -netns ${h} link set up dev eth0 fi done for i in 1 2 3 4 5; do h="host${i}" p=$((i - 1)) ph="host${p}" # connect to previous host if [ $i -gt 1 ]; then ip -netns ${ph} link set eth10${p} netns ${h} ip -netns ${h} link set eth10${p} name eth1 ip -netns ${h} link set up dev eth1 ip -netns ${h} addr add "${AB}.${p}.2/24" dev eth1 fi # add forward routes for k in $(seq ${i} $((5 - 1))); do ip -netns ${h} route 2>/dev/null | (grep "${AB}.${k}.0" 2>/dev/null) || \ ip -netns ${h} route add "${AB}.${k}.0/24" via "${AB}.${i}.2" 2>/dev/nul done # add reverse routes for k in $(seq 1 $((i - 2))); do ip -netns ${h} route 2>/dev/null | grep "${AB}.${k}.0" 2>/dev/null || \ ip -netns ${h} route add "${AB}.${k}.0/24" via "${AB}.${p}.1" 2>/dev/nul done done ip netns exec host1 ping -q -W 2 -w 1 -c 1 10.1.4.2 2>&1>/dev/null && echo "success 10.1.4.2 reachable" || echo "ERROR" ip netns exec host1 ping -W 9 -w 5 -c 1 10.1.4.3 || echo "note the source address of unreachble" ip -netns host1 route flush cache ip netns exec host3 nft add table inet filter ip netns exec host3 nft add chain inet filter FORWARD { type filter hook forward priority filter\; policy drop \; } ip netns exec host3 nft add rule inet filter FORWARD counter ip protocol icmp drop ip netns exec host3 nft add rule inet filter FORWARD counter ip protocol esp accept ip netns exec host3 nft add rule inet filter FORWARD counter drop ip -netns host2 xfrm policy add src 10.1.1.0/24 dst 10.1.4.0/24 dir out \ flag icmp tmpl src 10.1.2.1 dst 10.1.3.2 proto esp reqid 1 mode tunnel ip -netns host2 xfrm policy add src 10.1.4.0/24 dst 10.1.1.0/24 dir in \ tmpl src 10.1.3.2 dst 10.1.2.1 proto esp reqid 2 mode tunnel ip -netns host2 xfrm policy add src 10.1.4.0/24 dst 10.1.1.0/24 dir fwd \ flag icmp tmpl src 10.1.3.2 dst 10.1.2.1 proto esp reqid 2 mode tunnel ip -netns host2 xfrm state add src 10.1.2.1 dst 10.1.3.2 proto esp spi 1 \ reqid 1 replay-window 1 mode tunnel aead 'rfc4106(gcm(aes))' \ 0x1111111111111111111111111111111111111111 96 \ sel src 10.1.1.0/24 dst 10.1.4.0/24 ip -netns host2 xfrm state add src 10.1.3.2 dst 10.1.2.1 proto esp spi 2 \ flag icmp reqid 2 replay-window 10 mode tunnel aead 'rfc4106(gcm(aes))' \ 0x2222222222222222222222222222222222222222 96 ip -netns host4 xfrm policy add src 10.1.4.0/24 dst 10.1.1.0/24 dir out \ flag icmp tmpl src 10.1.3.2 dst 10.1.2.1 proto esp reqid 1 mode tunnel ip -netns host4 xfrm policy add src 10.1.1.0/24 dst 10.1.4.0/24 dir in \ tmpl src 10.1.2.1 dst 10.1.3.2 proto esp reqid 2 mode tunnel ip -netns host4 xfrm policy add src 10.1.1.0/24 dst 10.1.4.0/24 dir fwd \ flag icmp tmpl src 10.1.2.1 dst 10.1.3.2 proto esp reqid 2 mode tunnel ip -netns host4 xfrm state add src 10.1.3.2 dst 10.1.2.1 proto esp spi 2 \ reqid 1 replay-window 1 mode tunnel aead 'rfc4106(gcm(aes))' \ 0x2222222222222222222222222222222222222222 96 ip -netns host4 xfrm state add src 10.1.2.1 dst 10.1.3.2 proto esp spi 1 \ reqid 2 replay-window 20 flag icmp mode tunnel aead 'rfc4106(gcm(aes))' \ 0x1111111111111111111111111111111111111111 96 \ sel src 10.1.1.0/24 dst 10.1.4.0/24 ip netns exec host1 ping -W 5 -c 1 10.1.4.2 2>&1 > /dev/null && echo "" ip netns exec host1 ping -W 5 -c 1 10.1.4.3 || echo "note source address" Again before the fix ping -W 5 -c 1 10.1.4.3 >From 10.1.4.3 icmp_seq=1 Destination Host Unreachable After the fix >From 10.1.3.2 icmp_seq=1 Destination Host Unreachable Signed-off-by: Antony Antony --- net/ipv4/icmp.c | 1 - 1 file changed, 1 deletion(-) diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index e63a3bf99617..bec234637122 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -555,7 +555,6 @@ static struct rtable *icmp_route_lookup(struct net *net, XFRM_LOOKUP_ICMP); if (!IS_ERR(rt2)) { dst_release(&rt->dst); - memcpy(fl4, &fl4_dec, sizeof(*fl4)); rt = rt2; } else if (PTR_ERR(rt2) == -EPERM) { if (rt)