[ Upstream commit 5d1549847c76b1ffcf8e388ef4d0f229bdd1d7e8 ]
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.zhao@windriver.com Signed-off-by: He Zhe zhe.he@windriver.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 9becac953587..71a84a0517f3 100644 --- a/net/netfilter/nf_conntrack_proto_icmp.c +++ b/net/netfilter/nf_conntrack_proto_icmp.c @@ -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; } diff --git a/net/netfilter/nf_nat_proto.c b/net/netfilter/nf_nat_proto.c index 62743da3004f..0b0efbb953bf 100644 --- a/net/netfilter/nf_nat_proto.c +++ b/net/netfilter/nf_nat_proto.c @@ -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; 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,