KOVACS Krisztian | 136cdc7 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Transparent proxy support for Linux/iptables |
| 3 | * |
| 4 | * Copyright (C) 2007-2008 BalaBit IT Ltd. |
| 5 | * Author: Krisztian Kovacs |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License version 2 as |
| 9 | * published by the Free Software Foundation. |
| 10 | * |
| 11 | */ |
Jan Engelhardt | ff67e4e | 2010-03-19 21:08:16 +0100 | [diff] [blame] | 12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
KOVACS Krisztian | 136cdc7 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 13 | #include <linux/module.h> |
| 14 | #include <linux/skbuff.h> |
| 15 | #include <linux/netfilter/x_tables.h> |
| 16 | #include <linux/netfilter_ipv4/ip_tables.h> |
| 17 | #include <net/tcp.h> |
| 18 | #include <net/udp.h> |
| 19 | #include <net/icmp.h> |
| 20 | #include <net/sock.h> |
| 21 | #include <net/inet_sock.h> |
| 22 | #include <net/netfilter/nf_tproxy_core.h> |
| 23 | #include <net/netfilter/ipv4/nf_defrag_ipv4.h> |
KOVACS Krisztian | f6318e5 | 2010-10-24 23:38:32 +0000 | [diff] [blame] | 24 | |
| 25 | #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE) |
| 26 | #define XT_SOCKET_HAVE_IPV6 1 |
| 27 | #include <linux/netfilter_ipv6/ip6_tables.h> |
Balazs Scheidler | b64c925 | 2010-10-21 16:19:42 +0200 | [diff] [blame] | 28 | #include <net/netfilter/ipv6/nf_defrag_ipv6.h> |
KOVACS Krisztian | f6318e5 | 2010-10-24 23:38:32 +0000 | [diff] [blame] | 29 | #endif |
KOVACS Krisztian | 136cdc7 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 30 | |
Laszlo Attila Toth | a31e1ff | 2009-06-09 15:16:34 +0200 | [diff] [blame] | 31 | #include <linux/netfilter/xt_socket.h> |
| 32 | |
KOVACS Krisztian | 136cdc7 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 33 | #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) |
| 34 | #define XT_SOCKET_HAVE_CONNTRACK 1 |
| 35 | #include <net/netfilter/nf_conntrack.h> |
| 36 | #endif |
| 37 | |
| 38 | static int |
Balazs Scheidler | b64c925 | 2010-10-21 16:19:42 +0200 | [diff] [blame] | 39 | extract_icmp4_fields(const struct sk_buff *skb, |
KOVACS Krisztian | 136cdc7 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 40 | u8 *protocol, |
| 41 | __be32 *raddr, |
| 42 | __be32 *laddr, |
| 43 | __be16 *rport, |
| 44 | __be16 *lport) |
| 45 | { |
| 46 | unsigned int outside_hdrlen = ip_hdrlen(skb); |
| 47 | struct iphdr *inside_iph, _inside_iph; |
| 48 | struct icmphdr *icmph, _icmph; |
| 49 | __be16 *ports, _ports[2]; |
| 50 | |
| 51 | icmph = skb_header_pointer(skb, outside_hdrlen, |
| 52 | sizeof(_icmph), &_icmph); |
| 53 | if (icmph == NULL) |
| 54 | return 1; |
| 55 | |
| 56 | switch (icmph->type) { |
| 57 | case ICMP_DEST_UNREACH: |
| 58 | case ICMP_SOURCE_QUENCH: |
| 59 | case ICMP_REDIRECT: |
| 60 | case ICMP_TIME_EXCEEDED: |
| 61 | case ICMP_PARAMETERPROB: |
| 62 | break; |
| 63 | default: |
| 64 | return 1; |
| 65 | } |
| 66 | |
| 67 | inside_iph = skb_header_pointer(skb, outside_hdrlen + |
| 68 | sizeof(struct icmphdr), |
| 69 | sizeof(_inside_iph), &_inside_iph); |
| 70 | if (inside_iph == NULL) |
| 71 | return 1; |
| 72 | |
| 73 | if (inside_iph->protocol != IPPROTO_TCP && |
| 74 | inside_iph->protocol != IPPROTO_UDP) |
| 75 | return 1; |
| 76 | |
| 77 | ports = skb_header_pointer(skb, outside_hdrlen + |
| 78 | sizeof(struct icmphdr) + |
| 79 | (inside_iph->ihl << 2), |
| 80 | sizeof(_ports), &_ports); |
| 81 | if (ports == NULL) |
| 82 | return 1; |
| 83 | |
| 84 | /* the inside IP packet is the one quoted from our side, thus |
| 85 | * its saddr is the local address */ |
| 86 | *protocol = inside_iph->protocol; |
| 87 | *laddr = inside_iph->saddr; |
| 88 | *lport = ports[0]; |
| 89 | *raddr = inside_iph->daddr; |
| 90 | *rport = ports[1]; |
| 91 | |
| 92 | return 0; |
| 93 | } |
| 94 | |
KOVACS Krisztian | 136cdc7 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 95 | static bool |
Jan Engelhardt | 62fc805 | 2009-07-07 20:42:08 +0200 | [diff] [blame] | 96 | socket_match(const struct sk_buff *skb, struct xt_action_param *par, |
Laszlo Attila Toth | a31e1ff | 2009-06-09 15:16:34 +0200 | [diff] [blame] | 97 | const struct xt_socket_mtinfo1 *info) |
KOVACS Krisztian | 136cdc7 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 98 | { |
| 99 | const struct iphdr *iph = ip_hdr(skb); |
| 100 | struct udphdr _hdr, *hp = NULL; |
| 101 | struct sock *sk; |
| 102 | __be32 daddr, saddr; |
| 103 | __be16 dport, sport; |
| 104 | u8 protocol; |
| 105 | #ifdef XT_SOCKET_HAVE_CONNTRACK |
| 106 | struct nf_conn const *ct; |
| 107 | enum ip_conntrack_info ctinfo; |
| 108 | #endif |
| 109 | |
| 110 | if (iph->protocol == IPPROTO_UDP || iph->protocol == IPPROTO_TCP) { |
| 111 | hp = skb_header_pointer(skb, ip_hdrlen(skb), |
| 112 | sizeof(_hdr), &_hdr); |
| 113 | if (hp == NULL) |
| 114 | return false; |
| 115 | |
| 116 | protocol = iph->protocol; |
| 117 | saddr = iph->saddr; |
| 118 | sport = hp->source; |
| 119 | daddr = iph->daddr; |
| 120 | dport = hp->dest; |
| 121 | |
| 122 | } else if (iph->protocol == IPPROTO_ICMP) { |
Balazs Scheidler | b64c925 | 2010-10-21 16:19:42 +0200 | [diff] [blame] | 123 | if (extract_icmp4_fields(skb, &protocol, &saddr, &daddr, |
KOVACS Krisztian | 136cdc7 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 124 | &sport, &dport)) |
| 125 | return false; |
| 126 | } else { |
| 127 | return false; |
| 128 | } |
| 129 | |
| 130 | #ifdef XT_SOCKET_HAVE_CONNTRACK |
| 131 | /* Do the lookup with the original socket address in case this is a |
| 132 | * reply packet of an established SNAT-ted connection. */ |
| 133 | |
| 134 | ct = nf_ct_get(skb, &ctinfo); |
Eric Dumazet | 5bfddbd | 2010-06-08 16:09:52 +0200 | [diff] [blame] | 135 | if (ct && !nf_ct_is_untracked(ct) && |
KOVACS Krisztian | 136cdc7 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 136 | ((iph->protocol != IPPROTO_ICMP && |
| 137 | ctinfo == IP_CT_IS_REPLY + IP_CT_ESTABLISHED) || |
| 138 | (iph->protocol == IPPROTO_ICMP && |
| 139 | ctinfo == IP_CT_IS_REPLY + IP_CT_RELATED)) && |
| 140 | (ct->status & IPS_SRC_NAT_DONE)) { |
| 141 | |
| 142 | daddr = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip; |
| 143 | dport = (iph->protocol == IPPROTO_TCP) ? |
| 144 | ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.tcp.port : |
| 145 | ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.udp.port; |
| 146 | } |
| 147 | #endif |
| 148 | |
| 149 | sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), protocol, |
Balazs Scheidler | 106e4c2 | 2010-10-21 12:45:14 +0200 | [diff] [blame] | 150 | saddr, daddr, sport, dport, par->in, NFT_LOOKUP_ANY); |
KOVACS Krisztian | 136cdc7 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 151 | if (sk != NULL) { |
Laszlo Attila Toth | a31e1ff | 2009-06-09 15:16:34 +0200 | [diff] [blame] | 152 | bool wildcard; |
| 153 | bool transparent = true; |
| 154 | |
| 155 | /* Ignore sockets listening on INADDR_ANY */ |
| 156 | wildcard = (sk->sk_state != TCP_TIME_WAIT && |
Eric Dumazet | c720c7e | 2009-10-15 06:30:45 +0000 | [diff] [blame] | 157 | inet_sk(sk)->inet_rcv_saddr == 0); |
Laszlo Attila Toth | a31e1ff | 2009-06-09 15:16:34 +0200 | [diff] [blame] | 158 | |
| 159 | /* Ignore non-transparent sockets, |
| 160 | if XT_SOCKET_TRANSPARENT is used */ |
| 161 | if (info && info->flags & XT_SOCKET_TRANSPARENT) |
| 162 | transparent = ((sk->sk_state != TCP_TIME_WAIT && |
| 163 | inet_sk(sk)->transparent) || |
| 164 | (sk->sk_state == TCP_TIME_WAIT && |
| 165 | inet_twsk(sk)->tw_transparent)); |
KOVACS Krisztian | 136cdc7 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 166 | |
| 167 | nf_tproxy_put_sock(sk); |
Laszlo Attila Toth | a31e1ff | 2009-06-09 15:16:34 +0200 | [diff] [blame] | 168 | |
| 169 | if (wildcard || !transparent) |
KOVACS Krisztian | 136cdc7 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 170 | sk = NULL; |
| 171 | } |
| 172 | |
Balazs Scheidler | b64c925 | 2010-10-21 16:19:42 +0200 | [diff] [blame] | 173 | pr_debug("proto %hhu %pI4:%hu -> %pI4:%hu (orig %pI4:%hu) sock %p\n", |
| 174 | protocol, &saddr, ntohs(sport), |
| 175 | &daddr, ntohs(dport), |
| 176 | &iph->daddr, hp ? ntohs(hp->dest) : 0, sk); |
KOVACS Krisztian | 136cdc7 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 177 | |
| 178 | return (sk != NULL); |
| 179 | } |
| 180 | |
Laszlo Attila Toth | a31e1ff | 2009-06-09 15:16:34 +0200 | [diff] [blame] | 181 | static bool |
Balazs Scheidler | b64c925 | 2010-10-21 16:19:42 +0200 | [diff] [blame] | 182 | socket_mt4_v0(const struct sk_buff *skb, struct xt_action_param *par) |
Laszlo Attila Toth | a31e1ff | 2009-06-09 15:16:34 +0200 | [diff] [blame] | 183 | { |
| 184 | return socket_match(skb, par, NULL); |
| 185 | } |
| 186 | |
| 187 | static bool |
Balazs Scheidler | b64c925 | 2010-10-21 16:19:42 +0200 | [diff] [blame] | 188 | socket_mt4_v1(const struct sk_buff *skb, struct xt_action_param *par) |
Laszlo Attila Toth | a31e1ff | 2009-06-09 15:16:34 +0200 | [diff] [blame] | 189 | { |
| 190 | return socket_match(skb, par, par->matchinfo); |
| 191 | } |
| 192 | |
KOVACS Krisztian | f6318e5 | 2010-10-24 23:38:32 +0000 | [diff] [blame] | 193 | #ifdef XT_SOCKET_HAVE_IPV6 |
Balazs Scheidler | b64c925 | 2010-10-21 16:19:42 +0200 | [diff] [blame] | 194 | |
| 195 | static int |
| 196 | extract_icmp6_fields(const struct sk_buff *skb, |
| 197 | unsigned int outside_hdrlen, |
David S. Miller | 089282f | 2010-10-28 12:59:53 -0700 | [diff] [blame^] | 198 | int *protocol, |
Balazs Scheidler | b64c925 | 2010-10-21 16:19:42 +0200 | [diff] [blame] | 199 | struct in6_addr **raddr, |
| 200 | struct in6_addr **laddr, |
| 201 | __be16 *rport, |
| 202 | __be16 *lport) |
| 203 | { |
| 204 | struct ipv6hdr *inside_iph, _inside_iph; |
| 205 | struct icmp6hdr *icmph, _icmph; |
| 206 | __be16 *ports, _ports[2]; |
| 207 | u8 inside_nexthdr; |
| 208 | int inside_hdrlen; |
| 209 | |
| 210 | icmph = skb_header_pointer(skb, outside_hdrlen, |
| 211 | sizeof(_icmph), &_icmph); |
| 212 | if (icmph == NULL) |
| 213 | return 1; |
| 214 | |
| 215 | if (icmph->icmp6_type & ICMPV6_INFOMSG_MASK) |
| 216 | return 1; |
| 217 | |
| 218 | inside_iph = skb_header_pointer(skb, outside_hdrlen + sizeof(_icmph), sizeof(_inside_iph), &_inside_iph); |
| 219 | if (inside_iph == NULL) |
| 220 | return 1; |
| 221 | inside_nexthdr = inside_iph->nexthdr; |
| 222 | |
| 223 | inside_hdrlen = ipv6_skip_exthdr(skb, outside_hdrlen + sizeof(_icmph) + sizeof(_inside_iph), &inside_nexthdr); |
| 224 | if (inside_hdrlen < 0) |
| 225 | return 1; /* hjm: Packet has no/incomplete transport layer headers. */ |
| 226 | |
| 227 | if (inside_nexthdr != IPPROTO_TCP && |
| 228 | inside_nexthdr != IPPROTO_UDP) |
| 229 | return 1; |
| 230 | |
| 231 | ports = skb_header_pointer(skb, inside_hdrlen, |
| 232 | sizeof(_ports), &_ports); |
| 233 | if (ports == NULL) |
| 234 | return 1; |
| 235 | |
| 236 | /* the inside IP packet is the one quoted from our side, thus |
| 237 | * its saddr is the local address */ |
| 238 | *protocol = inside_nexthdr; |
| 239 | *laddr = &inside_iph->saddr; |
| 240 | *lport = ports[0]; |
| 241 | *raddr = &inside_iph->daddr; |
| 242 | *rport = ports[1]; |
| 243 | |
| 244 | return 0; |
| 245 | } |
| 246 | |
| 247 | static bool |
| 248 | socket_mt6_v1(const struct sk_buff *skb, struct xt_action_param *par) |
| 249 | { |
| 250 | struct ipv6hdr *iph = ipv6_hdr(skb); |
| 251 | struct udphdr _hdr, *hp = NULL; |
| 252 | struct sock *sk; |
| 253 | struct in6_addr *daddr, *saddr; |
| 254 | __be16 dport, sport; |
David S. Miller | 089282f | 2010-10-28 12:59:53 -0700 | [diff] [blame^] | 255 | int thoff, tproto; |
Balazs Scheidler | b64c925 | 2010-10-21 16:19:42 +0200 | [diff] [blame] | 256 | const struct xt_socket_mtinfo1 *info = (struct xt_socket_mtinfo1 *) par->matchinfo; |
| 257 | |
| 258 | tproto = ipv6_find_hdr(skb, &thoff, -1, NULL); |
| 259 | if (tproto < 0) { |
| 260 | pr_debug("unable to find transport header in IPv6 packet, dropping\n"); |
| 261 | return NF_DROP; |
| 262 | } |
| 263 | |
| 264 | if (tproto == IPPROTO_UDP || tproto == IPPROTO_TCP) { |
| 265 | hp = skb_header_pointer(skb, thoff, |
| 266 | sizeof(_hdr), &_hdr); |
| 267 | if (hp == NULL) |
| 268 | return false; |
| 269 | |
| 270 | saddr = &iph->saddr; |
| 271 | sport = hp->source; |
| 272 | daddr = &iph->daddr; |
| 273 | dport = hp->dest; |
| 274 | |
| 275 | } else if (tproto == IPPROTO_ICMPV6) { |
| 276 | if (extract_icmp6_fields(skb, thoff, &tproto, &saddr, &daddr, |
| 277 | &sport, &dport)) |
| 278 | return false; |
| 279 | } else { |
| 280 | return false; |
| 281 | } |
| 282 | |
| 283 | sk = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto, |
| 284 | saddr, daddr, sport, dport, par->in, NFT_LOOKUP_ANY); |
| 285 | if (sk != NULL) { |
| 286 | bool wildcard; |
| 287 | bool transparent = true; |
| 288 | |
| 289 | /* Ignore sockets listening on INADDR_ANY */ |
| 290 | wildcard = (sk->sk_state != TCP_TIME_WAIT && |
| 291 | ipv6_addr_any(&inet6_sk(sk)->rcv_saddr)); |
| 292 | |
| 293 | /* Ignore non-transparent sockets, |
| 294 | if XT_SOCKET_TRANSPARENT is used */ |
| 295 | if (info && info->flags & XT_SOCKET_TRANSPARENT) |
| 296 | transparent = ((sk->sk_state != TCP_TIME_WAIT && |
| 297 | inet_sk(sk)->transparent) || |
| 298 | (sk->sk_state == TCP_TIME_WAIT && |
| 299 | inet_twsk(sk)->tw_transparent)); |
| 300 | |
| 301 | nf_tproxy_put_sock(sk); |
| 302 | |
| 303 | if (wildcard || !transparent) |
| 304 | sk = NULL; |
| 305 | } |
| 306 | |
David S. Miller | 089282f | 2010-10-28 12:59:53 -0700 | [diff] [blame^] | 307 | pr_debug("proto %hhd %pI6:%hu -> %pI6:%hu " |
Balazs Scheidler | b64c925 | 2010-10-21 16:19:42 +0200 | [diff] [blame] | 308 | "(orig %pI6:%hu) sock %p\n", |
| 309 | tproto, saddr, ntohs(sport), |
| 310 | daddr, ntohs(dport), |
| 311 | &iph->daddr, hp ? ntohs(hp->dest) : 0, sk); |
| 312 | |
| 313 | return (sk != NULL); |
| 314 | } |
| 315 | #endif |
| 316 | |
Laszlo Attila Toth | a31e1ff | 2009-06-09 15:16:34 +0200 | [diff] [blame] | 317 | static struct xt_match socket_mt_reg[] __read_mostly = { |
| 318 | { |
| 319 | .name = "socket", |
| 320 | .revision = 0, |
| 321 | .family = NFPROTO_IPV4, |
Balazs Scheidler | b64c925 | 2010-10-21 16:19:42 +0200 | [diff] [blame] | 322 | .match = socket_mt4_v0, |
Jan Engelhardt | aa3c487 | 2009-10-29 15:35:10 +0100 | [diff] [blame] | 323 | .hooks = (1 << NF_INET_PRE_ROUTING) | |
| 324 | (1 << NF_INET_LOCAL_IN), |
Laszlo Attila Toth | a31e1ff | 2009-06-09 15:16:34 +0200 | [diff] [blame] | 325 | .me = THIS_MODULE, |
| 326 | }, |
| 327 | { |
| 328 | .name = "socket", |
| 329 | .revision = 1, |
| 330 | .family = NFPROTO_IPV4, |
Balazs Scheidler | b64c925 | 2010-10-21 16:19:42 +0200 | [diff] [blame] | 331 | .match = socket_mt4_v1, |
Laszlo Attila Toth | a31e1ff | 2009-06-09 15:16:34 +0200 | [diff] [blame] | 332 | .matchsize = sizeof(struct xt_socket_mtinfo1), |
Jan Engelhardt | aa3c487 | 2009-10-29 15:35:10 +0100 | [diff] [blame] | 333 | .hooks = (1 << NF_INET_PRE_ROUTING) | |
| 334 | (1 << NF_INET_LOCAL_IN), |
Laszlo Attila Toth | a31e1ff | 2009-06-09 15:16:34 +0200 | [diff] [blame] | 335 | .me = THIS_MODULE, |
| 336 | }, |
KOVACS Krisztian | f6318e5 | 2010-10-24 23:38:32 +0000 | [diff] [blame] | 337 | #ifdef XT_SOCKET_HAVE_IPV6 |
Balazs Scheidler | b64c925 | 2010-10-21 16:19:42 +0200 | [diff] [blame] | 338 | { |
| 339 | .name = "socket", |
| 340 | .revision = 1, |
| 341 | .family = NFPROTO_IPV6, |
| 342 | .match = socket_mt6_v1, |
| 343 | .matchsize = sizeof(struct xt_socket_mtinfo1), |
| 344 | .hooks = (1 << NF_INET_PRE_ROUTING) | |
| 345 | (1 << NF_INET_LOCAL_IN), |
| 346 | .me = THIS_MODULE, |
| 347 | }, |
| 348 | #endif |
KOVACS Krisztian | 136cdc7 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 349 | }; |
| 350 | |
| 351 | static int __init socket_mt_init(void) |
| 352 | { |
| 353 | nf_defrag_ipv4_enable(); |
KOVACS Krisztian | f6318e5 | 2010-10-24 23:38:32 +0000 | [diff] [blame] | 354 | #ifdef XT_SOCKET_HAVE_IPV6 |
Balazs Scheidler | b64c925 | 2010-10-21 16:19:42 +0200 | [diff] [blame] | 355 | nf_defrag_ipv6_enable(); |
| 356 | #endif |
| 357 | |
Laszlo Attila Toth | a31e1ff | 2009-06-09 15:16:34 +0200 | [diff] [blame] | 358 | return xt_register_matches(socket_mt_reg, ARRAY_SIZE(socket_mt_reg)); |
KOVACS Krisztian | 136cdc7 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 359 | } |
| 360 | |
| 361 | static void __exit socket_mt_exit(void) |
| 362 | { |
Laszlo Attila Toth | a31e1ff | 2009-06-09 15:16:34 +0200 | [diff] [blame] | 363 | xt_unregister_matches(socket_mt_reg, ARRAY_SIZE(socket_mt_reg)); |
KOVACS Krisztian | 136cdc7 | 2008-10-08 11:35:12 +0200 | [diff] [blame] | 364 | } |
| 365 | |
| 366 | module_init(socket_mt_init); |
| 367 | module_exit(socket_mt_exit); |
| 368 | |
| 369 | MODULE_LICENSE("GPL"); |
| 370 | MODULE_AUTHOR("Krisztian Kovacs, Balazs Scheidler"); |
| 371 | MODULE_DESCRIPTION("x_tables socket match module"); |
| 372 | MODULE_ALIAS("ipt_socket"); |
Balazs Scheidler | b64c925 | 2010-10-21 16:19:42 +0200 | [diff] [blame] | 373 | MODULE_ALIAS("ip6t_socket"); |