From 6150bacfec95c7042678667561664efcf10d4508 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Tue, 21 Jun 2005 14:03:46 -0700 Subject: [PATCH] [NETFILTER]: Check TCP checksum in ipt_REJECT Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- net/ipv4/netfilter/ipt_REJECT.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/net/ipv4/netfilter/ipt_REJECT.c b/net/ipv4/netfilter/ipt_REJECT.c index 266d64979286..915696446020 100644 --- a/net/ipv4/netfilter/ipt_REJECT.c +++ b/net/ipv4/netfilter/ipt_REJECT.c @@ -104,10 +104,12 @@ static inline struct rtable *route_reverse(struct sk_buff *skb, static void send_reset(struct sk_buff *oldskb, int hook) { struct sk_buff *nskb; + struct iphdr *iph = oldskb->nh.iph; struct tcphdr _otcph, *oth, *tcph; struct rtable *rt; u_int16_t tmp_port; u_int32_t tmp_addr; + unsigned int tcplen; int needs_ack; int hh_len; @@ -124,7 +126,16 @@ static void send_reset(struct sk_buff *oldskb, int hook) if (oth->rst) return; - /* FIXME: Check checksum --RR */ + /* Check checksum */ + tcplen = oldskb->len - iph->ihl * 4; + if (((hook != NF_IP_LOCAL_IN && oldskb->ip_summed != CHECKSUM_HW) || + (hook == NF_IP_LOCAL_IN && + oldskb->ip_summed != CHECKSUM_UNNECESSARY)) && + csum_tcpudp_magic(iph->saddr, iph->daddr, tcplen, IPPROTO_TCP, + oldskb->ip_summed == CHECKSUM_HW ? oldskb->csum : + skb_checksum(oldskb, iph->ihl * 4, tcplen, 0))) + return; + if ((rt = route_reverse(oldskb, oth, hook)) == NULL) return; -- 2.30.2