diff -urN -X /tmp/fileVB9oIz --minimal tmp/include/linux/netfilter_ipv4/ipt_REJECT.h working-2.4.0-test3-9/include/linux/netfilter_ipv4/ipt_REJECT.h --- tmp/include/linux/netfilter_ipv4/ipt_REJECT.h Tue Mar 28 04:35:56 2000 +++ working-2.4.0-test3-9/include/linux/netfilter_ipv4/ipt_REJECT.h Tue Jul 11 17:36:54 2000 @@ -6,7 +6,10 @@ IPT_ICMP_HOST_UNREACHABLE, IPT_ICMP_PROT_UNREACHABLE, IPT_ICMP_PORT_UNREACHABLE, - IPT_ICMP_ECHOREPLY + IPT_ICMP_ECHOREPLY, + IPT_ICMP_NET_PROHIBITED, + IPT_ICMP_HOST_PROHIBITED, + IPT_TCP_RESET }; struct ipt_reject_info { diff -urN -X /tmp/fileVB9oIz --minimal tmp/net/core/netfilter.c working-2.4.0-test3-9/net/core/netfilter.c --- tmp/net/core/netfilter.c Fri Apr 14 10:19:57 2000 +++ working-2.4.0-test3-9/net/core/netfilter.c Wed Jul 12 12:18:42 2000 @@ -261,11 +261,11 @@ if (skb->nf_debug != ((1 << NF_IP_PRE_ROUTING) | (1 << NF_IP_FORWARD) | (1 << NF_IP_POST_ROUTING))) { - /* Fragments will have no owners, but still - may be local */ - if (!(skb->nh.iph->frag_off & htons(IP_MF|IP_OFFSET)) - || skb->nf_debug != ((1 << NF_IP_LOCAL_OUT) - | (1 << NF_IP_POST_ROUTING))){ + /* Fragments, entunnelled packets, TCP RSTs + generated by ipt_REJECT will have no + owners, but still may be local */ + if (skb->nf_debug != ((1 << NF_IP_LOCAL_OUT) + | (1 << NF_IP_POST_ROUTING))){ printk("ip_finish_output:" " bad unowned skb = %p: ",skb); debug_print_hooks_ip(skb->nf_debug); diff -urN -X /tmp/fileVB9oIz --minimal tmp/net/ipv4/netfilter/ip_conntrack_core.c working-2.4.0-test3-9/net/ipv4/netfilter/ip_conntrack_core.c --- tmp/net/ipv4/netfilter/ip_conntrack_core.c Tue Jul 11 12:08:17 2000 +++ working-2.4.0-test3-9/net/ipv4/netfilter/ip_conntrack_core.c Tue Jul 11 17:12:08 2000 @@ -551,6 +551,7 @@ resolve_normal_ct(struct sk_buff *skb, struct ip_conntrack_protocol *proto, int *set_reply, + unsigned int hooknum, enum ip_conntrack_info *ctinfo) { struct ip_conntrack_tuple tuple; @@ -573,6 +574,21 @@ if (DIRECTION(h) == IP_CT_DIR_REPLY) { /* Reply on unconfirmed connection => unclassifiable */ if (!(h->ctrack->status & IPS_CONFIRMED)) { + /* Exception: local TCP RSTs (generated by + REJECT target). */ + if (hooknum == NF_IP_LOCAL_OUT + && h->tuple.dst.protonum == IPPROTO_TCP) { + const struct tcphdr *tcph + = (const struct tcphdr *) + ((u_int32_t *)skb->nh.iph + + skb->nh.iph->ihl); + if (tcph->rst) { + *ctinfo = IP_CT_ESTABLISHED + + IP_CT_IS_REPLY; + *set_reply = 0; + goto set_skb; + } + } DEBUGP("Reply on unconfirmed connection\n"); ip_conntrack_put(h->ctrack); return NULL; @@ -598,6 +614,7 @@ } *set_reply = 0; } + set_skb: skb->nfct = &h->ctrack->infos[*ctinfo]; return h->ctrack; } @@ -669,7 +686,7 @@ && icmp_error_track(*pskb, &ctinfo, hooknum)) return NF_ACCEPT; - if (!(ct = resolve_normal_ct(*pskb, proto, &set_reply, &ctinfo))) + if (!(ct = resolve_normal_ct(*pskb, proto,&set_reply,hooknum,&ctinfo))) /* Not valid part of a connection */ return NF_ACCEPT; diff -urN -X /tmp/fileVB9oIz --minimal tmp/net/ipv4/netfilter/ip_conntrack_standalone.c working-2.4.0-test3-9/net/ipv4/netfilter/ip_conntrack_standalone.c --- tmp/net/ipv4/netfilter/ip_conntrack_standalone.c Fri Apr 28 08:43:15 2000 +++ working-2.4.0-test3-9/net/ipv4/netfilter/ip_conntrack_standalone.c Tue Jul 11 17:12:08 2000 @@ -169,11 +169,15 @@ const struct net_device *out, int (*okfn)(struct sk_buff *)) { - /* We've seen it coming out the other side: confirm */ + /* We've seen it coming out the other side: confirm (only if + new packet: REJECT can generate TCP RESET response, or ICMP + errors) */ if ((*pskb)->nfct) { struct ip_conntrack *ct = (struct ip_conntrack *)(*pskb)->nfct->master; - if (!(ct->status & IPS_CONFIRMED)) + /* ctinfo is the index of the nfct inside the conntrack */ + if ((*pskb)->nfct - ct->infos == IP_CT_NEW + && !(ct->status & IPS_CONFIRMED)) ip_conntrack_confirm(ct); } return NF_ACCEPT; @@ -191,7 +195,8 @@ if ((*pskb)->nfct) { struct ip_conntrack *ct = (struct ip_conntrack *)(*pskb)->nfct->master; - if (!(ct->status & IPS_CONFIRMED)) + if ((*pskb)->nfct - ct->infos == IP_CT_NEW + && !(ct->status & IPS_CONFIRMED)) ip_conntrack_confirm(ct); } diff -urN -X /tmp/fileVB9oIz --minimal tmp/net/ipv4/netfilter/ip_fw_compat.c working-2.4.0-test3-9/net/ipv4/netfilter/ip_fw_compat.c --- tmp/net/ipv4/netfilter/ip_fw_compat.c Tue Jul 11 12:08:17 2000 +++ working-2.4.0-test3-9/net/ipv4/netfilter/ip_fw_compat.c Tue Jul 11 17:12:08 2000 @@ -71,7 +71,8 @@ struct ip_conntrack *ct = (struct ip_conntrack *)skb->nfct->master; - if (!(ct->status & IPS_CONFIRMED)) + if (skb->nfct - ct->infos == IP_CT_NEW + && !(ct->status & IPS_CONFIRMED)) ip_conntrack_confirm(ct); } } diff -urN -X /tmp/fileVB9oIz --minimal tmp/net/ipv4/netfilter/ipt_REJECT.c working-2.4.0-test3-9/net/ipv4/netfilter/ipt_REJECT.c --- tmp/net/ipv4/netfilter/ipt_REJECT.c Tue Jun 27 14:52:47 2000 +++ working-2.4.0-test3-9/net/ipv4/netfilter/ipt_REJECT.c Wed Jul 12 17:46:26 2000 @@ -7,6 +7,7 @@ #include #include #include +#include struct in_device; #include #include @@ -18,6 +19,113 @@ #define DEBUGP(format, args...) #endif +/* Send RST reply */ +static void send_reset(struct sk_buff *oldskb) +{ + struct sk_buff *nskb; + struct tcphdr *tcph; + struct rtable *rt; + unsigned int tcplen; + int needs_ack; + + /* Clone skb (skb is about to be dropped, so we don't care) */ + nskb = skb_clone(oldskb, GFP_ATOMIC); + if (!nskb) + return; + + /* This packet will not be the same as the other: clear nf fields */ + nf_conntrack_put(nskb->nfct); + nskb->nfct = NULL; + nskb->nfcache = 0; +#ifdef CONFIG_NETFILTER_DEBUG + nskb->nf_debug = 0; +#endif + + /* IP header checks: fragment, too short. */ + if (nskb->nh.iph->frag_off & htons(IP_OFFSET) + || nskb->len < (nskb->nh.iph->ihl<<2) + sizeof(struct tcphdr)) + goto free_nskb; + + tcph = (struct tcphdr *)((u_int32_t*)nskb->nh.iph + nskb->nh.iph->ihl); + tcplen = nskb->len - nskb->nh.iph->ihl*4; + + /* Check checksum. */ + if (tcp_v4_check(tcph, tcplen, nskb->nh.iph->saddr, + nskb->nh.iph->daddr, + csum_partial((char *)tcph, tcplen, 0)) != 0) + goto free_nskb; + + /* No RST for RST. */ + if (tcph->rst) + goto free_nskb; + + nskb->nh.iph->daddr = xchg(&nskb->nh.iph->saddr, nskb->nh.iph->daddr); + tcph->source = xchg(&tcph->dest, tcph->source); + + /* Truncate to length (no data) */ + tcph->doff = sizeof(struct tcphdr)/4; + skb_trim(nskb, nskb->nh.iph->ihl*4 + sizeof(struct tcphdr)); + + if (tcph->ack) { + needs_ack = 0; + tcph->seq = tcph->ack_seq; + tcph->ack_seq = 0; + } else { + needs_ack = 1; + tcph->seq = 0; + tcph->ack_seq = htonl(ntohl(tcph->seq) + tcph->syn + tcph->fin + + tcplen - (tcph->doff<<2)); + } + + /* Reset flags */ + ((u_int8_t *)tcph)[13] = 0; + tcph->rst = 1; + if (needs_ack) + tcph->ack = 1; + + tcph->window = 0; + tcph->urg_ptr = 0; + + /* Adjust TCP checksum */ + tcph->check = 0; + tcph->check = tcp_v4_check(tcph, sizeof(struct tcphdr), + nskb->nh.iph->saddr, + nskb->nh.iph->daddr, + csum_partial((char *)tcph, + sizeof(struct tcphdr), 0)); + + /* Adjust IP TTL, DF */ + nskb->nh.iph->ttl = MAXTTL; + /* Set DF, id = 0 */ + nskb->nh.iph->frag_off = htons(IP_DF); + nskb->nh.iph->id = 0; + + /* Adjust IP checksum */ + nskb->nh.iph->check = 0; + nskb->nh.iph->check = ip_fast_csum((unsigned char *)nskb->nh.iph, + nskb->nh.iph->ihl); + + /* Routing */ + if (ip_route_output(&rt, nskb->nh.iph->daddr, nskb->nh.iph->saddr, + RT_TOS(nskb->nh.iph->tos) | RTO_CONN, + 0) != 0) + goto free_nskb; + + dst_release(nskb->dst); + nskb->dst = &rt->u.dst; + + /* "Never happens" */ + if (nskb->len > nskb->dst->pmtu) + goto free_nskb; + + NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, nskb, NULL, nskb->dst->dev, + ip_finish_output); + return; + + free_nskb: + kfree_skb(nskb); +} + static unsigned int reject(struct sk_buff **pskb, unsigned int hooknum, const struct net_device *in, @@ -43,6 +151,12 @@ case IPT_ICMP_PORT_UNREACHABLE: icmp_send(*pskb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0); break; + case IPT_ICMP_NET_PROHIBITED: + icmp_send(*pskb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0); + break; + case IPT_ICMP_HOST_PROHIBITED: + icmp_send(*pskb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0); + break; case IPT_ICMP_ECHOREPLY: { struct icmphdr *icmph = (struct icmphdr *) ((u_int32_t *)(*pskb)->nh.iph + (*pskb)->nh.iph->ihl); @@ -64,6 +178,9 @@ } } break; + case IPT_TCP_RESET: + send_reset(*pskb); + break; } return NF_DROP; @@ -96,7 +213,7 @@ /* Only allow these for packet filtering. */ if (strcmp(tablename, "filter") != 0) { - DEBUGP("REJECT: bad table `%s'.\n", table); + DEBUGP("REJECT: bad table `%s'.\n", tablename); return 0; } if ((hook_mask & ~((1 << NF_IP_LOCAL_IN) @@ -116,6 +233,18 @@ /* Must contain ICMP match. */ if (IPT_MATCH_ITERATE(e, find_ping_match) == 0) { DEBUGP("REJECT: ECHOREPLY illegal for non-ping\n"); + return 0; + } + } else if (rejinfo->with == IPT_TCP_RESET) { + /* Must specify that it's a TCP packet */ + if (e->ip.proto != IPPROTO_TCP + || (e->ip.invflags & IPT_INV_PROTO)) { + DEBUGP("REJECT: TCP_RESET illegal for non-tcp\n"); + return 0; + } + /* Only for local input. Rest is too dangerous. */ + if ((hook_mask & ~(1 << NF_IP_LOCAL_IN)) != 0) { + DEBUGP("REJECT: TCP_RESET only from INPUT\n"); return 0; } }