netfilter: Fix remainder of pseudo-header protocol 0 (5d154984) · Commits · 戴 / test

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: ("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: ("netfilter: reject: skip csum verification for protocols that don't support it") Reported-by:

Yi Zhao <yi.zhao@windriver.com> Signed-off-by:

He Zhe <zhe.he@windriver.com> Signed-off-by:

Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_conntrack_proto_icmp.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -221,7 +221,7 @@ 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;
		}

net/netfilter/nf_nat_proto.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -567,7 +567,7 @@ 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;

net/netfilter/utils.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -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,

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