From: He Zhe <zhe...@windriver.com>

1/1 [
Author: He Zhe
Email: zhe...@windriver.com
Subject: netfilter: Fix remainder of pseudo-header protocol 0
Date: Tue, 25 Jun 2019 18:15:50 +0800

Since v5.1-rc1, some types of packets do not get unreachable reply with the
following iptables setting. Fox example,

$ iptables -A INPUT -p icmp --icmp-type 8 -j REJECT
$ ping 127.0.0.1 -c 1
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
— 127.0.0.1 ping statistics —
1 packets transmitted, 0 received, 100% packet loss, time 0ms

We should have got the following reply from command line, but we did not.
From 127.0.0.1 icmp_seq=1 Destination Port Unreachable

Yi Zhao reported it and narrowed it down to:
7fc38225363d ("netfilter: reject: skip csum verification for protocols that 
don't support it"),

This is because nf_ip_checksum still expects pseudo-header protocol type 0 for
packets that are of neither TCP or UDP, and thus ICMP packets are mistakenly
treated as TCP/UDP.

This patch corrects the conditions in nf_ip_checksum and all other places that
still call it with protocol 0.

Fixes: 7fc38225363d ("netfilter: reject: skip csum verification for protocols 
that don't support it")
Reported-by: Yi Zhao <yi.z...@windriver.com>
Signed-off-by: He Zhe <zhe...@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfi...@gmail.com>
]
Signed-off-by: He Zhe <zhe...@windriver.com>
---
 patches/net/net.scc                                |  1 +
 ...Fix-remainder-of-pseudo-header-protocol-0.patch | 92 ++++++++++++++++++++++
 2 files changed, 93 insertions(+)
 create mode 100644 
patches/net/netfilter-Fix-remainder-of-pseudo-header-protocol-0.patch

diff --git a/patches/net/net.scc b/patches/net/net.scc
index 2b32bc7..d09118a 100644
--- a/patches/net/net.scc
+++ b/patches/net/net.scc
@@ -1 +1,2 @@
 patch Resolve-jiffies-wrapping-about-arp.patch
+patch netfilter-Fix-remainder-of-pseudo-header-protocol-0.patch
diff --git 
a/patches/net/netfilter-Fix-remainder-of-pseudo-header-protocol-0.patch 
b/patches/net/netfilter-Fix-remainder-of-pseudo-header-protocol-0.patch
new file mode 100644
index 0000000..d1fdbf9
--- /dev/null
+++ b/patches/net/netfilter-Fix-remainder-of-pseudo-header-protocol-0.patch
@@ -0,0 +1,92 @@
+From b383959122e464ccdc21f6b37af88152d29cdf95 Mon Sep 17 00:00:00 2001
+From: He Zhe <zhe...@windriver.com>
+Date: Tue, 25 Jun 2019 18:15:50 +0800
+Subject: [PATCH] netfilter: Fix remainder of pseudo-header protocol 0
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Since v5.1-rc1, some types of packets do not get unreachable reply with the
+following iptables setting. Fox example,
+
+$ iptables -A INPUT -p icmp --icmp-type 8 -j REJECT
+$ ping 127.0.0.1 -c 1
+PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
+— 127.0.0.1 ping statistics —
+1 packets transmitted, 0 received, 100% packet loss, time 0ms
+
+We should have got the following reply from command line, but we did not.
+From 127.0.0.1 icmp_seq=1 Destination Port Unreachable
+
+Yi Zhao reported it and narrowed it down to:
+7fc38225363d ("netfilter: reject: skip csum verification for protocols that 
don't support it"),
+
+This is because nf_ip_checksum still expects pseudo-header protocol type 0 for
+packets that are of neither TCP or UDP, and thus ICMP packets are mistakenly
+treated as TCP/UDP.
+
+This patch corrects the conditions in nf_ip_checksum and all other places that
+still call it with protocol 0.
+
+Fixes: 7fc38225363d ("netfilter: reject: skip csum verification for protocols 
that don't support it")
+Reported-by: Yi Zhao <yi.z...@windriver.com>
+Signed-off-by: He Zhe <zhe...@windriver.com>
+Signed-off-by: Bruce Ashfield <bruce.ashfi...@gmail.com>
+---
+ net/netfilter/nf_conntrack_proto_icmp.c | 2 +-
+ net/netfilter/nf_nat_proto.c            | 2 +-
+ net/netfilter/utils.c                   | 5 +++--
+ 3 files changed, 5 insertions(+), 4 deletions(-)
+
+diff --git a/net/netfilter/nf_conntrack_proto_icmp.c 
b/net/netfilter/nf_conntrack_proto_icmp.c
+index a824367ed518..dd53e2b20f6b 100644
+--- a/net/netfilter/nf_conntrack_proto_icmp.c
++++ b/net/netfilter/nf_conntrack_proto_icmp.c
+@@ -218,7 +218,7 @@ int nf_conntrack_icmpv4_error(struct nf_conn *tmpl,
+       /* See ip_conntrack_proto_tcp.c */
+       if (state->net->ct.sysctl_checksum &&
+           state->hook == NF_INET_PRE_ROUTING &&
+-          nf_ip_checksum(skb, state->hook, dataoff, 0)) {
++          nf_ip_checksum(skb, state->hook, dataoff, IPPROTO_ICMP)) {
+               icmp_error_log(skb, state, "bad hw icmp checksum");
+               return -NF_ACCEPT;
+       }
+diff --git a/net/netfilter/nf_nat_proto.c b/net/netfilter/nf_nat_proto.c
+index 07da07788f6b..83a24cc5753b 100644
+--- a/net/netfilter/nf_nat_proto.c
++++ b/net/netfilter/nf_nat_proto.c
+@@ -564,7 +564,7 @@ int nf_nat_icmp_reply_translation(struct sk_buff *skb,
+ 
+       if (!skb_make_writable(skb, hdrlen + sizeof(*inside)))
+               return 0;
+-      if (nf_ip_checksum(skb, hooknum, hdrlen, 0))
++      if (nf_ip_checksum(skb, hooknum, hdrlen, IPPROTO_ICMP))
+               return 0;
+ 
+       inside = (void *)skb->data + hdrlen;
+diff --git a/net/netfilter/utils.c b/net/netfilter/utils.c
+index 06dc55590441..51b454d8fa9c 100644
+--- a/net/netfilter/utils.c
++++ b/net/netfilter/utils.c
+@@ -17,7 +17,8 @@ __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int 
hook,
+       case CHECKSUM_COMPLETE:
+               if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN)
+                       break;
+-              if ((protocol == 0 && !csum_fold(skb->csum)) ||
++              if ((protocol != IPPROTO_TCP && protocol != IPPROTO_UDP &&
++                  !csum_fold(skb->csum)) ||
+                   !csum_tcpudp_magic(iph->saddr, iph->daddr,
+                                      skb->len - dataoff, protocol,
+                                      skb->csum)) {
+@@ -26,7 +27,7 @@ __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int 
hook,
+               }
+               /* fall through */
+       case CHECKSUM_NONE:
+-              if (protocol == 0)
++              if (protocol != IPPROTO_TCP && protocol != IPPROTO_UDP)
+                       skb->csum = 0;
+               else
+                       skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
+-- 
+2.19.1
+
-- 
2.7.4

-- 
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