From 5d1549847c76b1ffcf8e388ef4d0f229bdd1d7e8 Mon Sep 17 00:00:00 2001 From: He Zhe Date: Mon, 24 Jun 2019 11:17:38 +0800 Subject: 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 Signed-off-by: He Zhe Signed-off-by: Pablo Neira Ayuso --- net/netfilter/utils.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'net/netfilter/utils.c') 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, -- cgit