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mfd: wm8350-i2c: Make sure the i2c regmap functions are compiled
[linux/fpc-iii.git] / net / netfilter / xt_socket.c
blobfcea773971ca4f8b148d81be92f53de74ecd9036
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 */
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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/ipv4/nf_defrag_ipv4.h>
23
24 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
25 #define XT_SOCKET_HAVE_IPV6 1
26 #include <linux/netfilter_ipv6/ip6_tables.h>
27 #include <net/inet6_hashtables.h>
28 #include <net/netfilter/ipv6/nf_defrag_ipv6.h>
29 #endif
30
31 #include <linux/netfilter/xt_socket.h>
32
33 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
34 #define XT_SOCKET_HAVE_CONNTRACK 1
35 #include <net/netfilter/nf_conntrack.h>
36 #endif
37
38 static void
39 xt_socket_put_sk(struct sock *sk)
40 {
41 if (sk->sk_state == TCP_TIME_WAIT)
42 inet_twsk_put(inet_twsk(sk));
43 else
44 sock_put(sk);
45 }
46
47 static int
48 extract_icmp4_fields(const struct sk_buff *skb,
49 u8 *protocol,
50 __be32 *raddr,
51 __be32 *laddr,
52 __be16 *rport,
53 __be16 *lport)
54 {
55 unsigned int outside_hdrlen = ip_hdrlen(skb);
56 struct iphdr *inside_iph, _inside_iph;
57 struct icmphdr *icmph, _icmph;
58 __be16 *ports, _ports[2];
59
60 icmph = skb_header_pointer(skb, outside_hdrlen,
61 sizeof(_icmph), &_icmph);
62 if (icmph == NULL)
63 return 1;
64
65 switch (icmph->type) {
66 case ICMP_DEST_UNREACH:
67 case ICMP_SOURCE_QUENCH:
68 case ICMP_REDIRECT:
69 case ICMP_TIME_EXCEEDED:
70 case ICMP_PARAMETERPROB:
71 break;
72 default:
73 return 1;
74 }
75
76 inside_iph = skb_header_pointer(skb, outside_hdrlen +
77 sizeof(struct icmphdr),
78 sizeof(_inside_iph), &_inside_iph);
79 if (inside_iph == NULL)
80 return 1;
81
82 if (inside_iph->protocol != IPPROTO_TCP &&
83 inside_iph->protocol != IPPROTO_UDP)
84 return 1;
85
86 ports = skb_header_pointer(skb, outside_hdrlen +
87 sizeof(struct icmphdr) +
88 (inside_iph->ihl << 2),
89 sizeof(_ports), &_ports);
90 if (ports == NULL)
91 return 1;
92
93 /* the inside IP packet is the one quoted from our side, thus
94 * its saddr is the local address */
95 *protocol = inside_iph->protocol;
96 *laddr = inside_iph->saddr;
97 *lport = ports[0];
98 *raddr = inside_iph->daddr;
99 *rport = ports[1];
100
101 return 0;
102 }
103
104 /* "socket" match based redirection (no specific rule)
105 * ===================================================
106 *
107 * There are connections with dynamic endpoints (e.g. FTP data
108 * connection) that the user is unable to add explicit rules
109 * for. These are taken care of by a generic "socket" rule. It is
110 * assumed that the proxy application is trusted to open such
111 * connections without explicit iptables rule (except of course the
112 * generic 'socket' rule). In this case the following sockets are
113 * matched in preference order:
114 *
115 * - match: if there's a fully established connection matching the
116 * _packet_ tuple
117 *
118 * - match: if there's a non-zero bound listener (possibly with a
119 * non-local address) We don't accept zero-bound listeners, since
120 * then local services could intercept traffic going through the
121 * box.
122 */
123 static struct sock *
124 xt_socket_get_sock_v4(struct net *net, const u8 protocol,
125 const __be32 saddr, const __be32 daddr,
126 const __be16 sport, const __be16 dport,
127 const struct net_device *in)
128 {
129 switch (protocol) {
130 case IPPROTO_TCP:
131 return __inet_lookup(net, &tcp_hashinfo,
132 saddr, sport, daddr, dport,
133 in->ifindex);
134 case IPPROTO_UDP:
135 return udp4_lib_lookup(net, saddr, sport, daddr, dport,
136 in->ifindex);
137 }
138 return NULL;
139 }
140
141 static bool
142 socket_match(const struct sk_buff *skb, struct xt_action_param *par,
143 const struct xt_socket_mtinfo1 *info)
144 {
145 const struct iphdr *iph = ip_hdr(skb);
146 struct udphdr _hdr, *hp = NULL;
147 struct sock *sk = skb->sk;
148 __be32 uninitialized_var(daddr), uninitialized_var(saddr);
149 __be16 uninitialized_var(dport), uninitialized_var(sport);
150 u8 uninitialized_var(protocol);
151 #ifdef XT_SOCKET_HAVE_CONNTRACK
152 struct nf_conn const *ct;
153 enum ip_conntrack_info ctinfo;
154 #endif
155
156 if (iph->protocol == IPPROTO_UDP || iph->protocol == IPPROTO_TCP) {
157 hp = skb_header_pointer(skb, ip_hdrlen(skb),
158 sizeof(_hdr), &_hdr);
159 if (hp == NULL)
160 return false;
161
162 protocol = iph->protocol;
163 saddr = iph->saddr;
164 sport = hp->source;
165 daddr = iph->daddr;
166 dport = hp->dest;
167
168 } else if (iph->protocol == IPPROTO_ICMP) {
169 if (extract_icmp4_fields(skb, &protocol, &saddr, &daddr,
170 &sport, &dport))
171 return false;
172 } else {
173 return false;
174 }
175
176 #ifdef XT_SOCKET_HAVE_CONNTRACK
177 /* Do the lookup with the original socket address in case this is a
178 * reply packet of an established SNAT-ted connection. */
179
180 ct = nf_ct_get(skb, &ctinfo);
181 if (ct && !nf_ct_is_untracked(ct) &&
182 ((iph->protocol != IPPROTO_ICMP &&
183 ctinfo == IP_CT_ESTABLISHED_REPLY) ||
184 (iph->protocol == IPPROTO_ICMP &&
185 ctinfo == IP_CT_RELATED_REPLY)) &&
186 (ct->status & IPS_SRC_NAT_DONE)) {
187
188 daddr = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
189 dport = (iph->protocol == IPPROTO_TCP) ?
190 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.tcp.port :
191 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.udp.port;
192 }
193 #endif
194
195 if (!sk)
196 sk = xt_socket_get_sock_v4(dev_net(skb->dev), protocol,
197 saddr, daddr, sport, dport,
198 par->in);
199 if (sk) {
200 bool wildcard;
201 bool transparent = true;
202
203 /* Ignore sockets listening on INADDR_ANY,
204 * unless XT_SOCKET_NOWILDCARD is set
205 */
206 wildcard = (!(info->flags & XT_SOCKET_NOWILDCARD) &&
207 sk->sk_state != TCP_TIME_WAIT &&
208 inet_sk(sk)->inet_rcv_saddr == 0);
209
210 /* Ignore non-transparent sockets,
211 if XT_SOCKET_TRANSPARENT is used */
212 if (info->flags & XT_SOCKET_TRANSPARENT)
213 transparent = ((sk->sk_state != TCP_TIME_WAIT &&
214 inet_sk(sk)->transparent) ||
215 (sk->sk_state == TCP_TIME_WAIT &&
216 inet_twsk(sk)->tw_transparent));
217
218 if (sk != skb->sk)
219 xt_socket_put_sk(sk);
220
221 if (wildcard || !transparent)
222 sk = NULL;
223 }
224
225 pr_debug("proto %hhu %pI4:%hu -> %pI4:%hu (orig %pI4:%hu) sock %p\n",
226 protocol, &saddr, ntohs(sport),
227 &daddr, ntohs(dport),
228 &iph->daddr, hp ? ntohs(hp->dest) : 0, sk);
229
230 return (sk != NULL);
231 }
232
233 static bool
234 socket_mt4_v0(const struct sk_buff *skb, struct xt_action_param *par)
235 {
236 static struct xt_socket_mtinfo1 xt_info_v0 = {
237 .flags = 0,
238 };
239
240 return socket_match(skb, par, &xt_info_v0);
241 }
242
243 static bool
244 socket_mt4_v1_v2(const struct sk_buff *skb, struct xt_action_param *par)
245 {
246 return socket_match(skb, par, par->matchinfo);
247 }
248
249 #ifdef XT_SOCKET_HAVE_IPV6
250
251 static int
252 extract_icmp6_fields(const struct sk_buff *skb,
253 unsigned int outside_hdrlen,
254 int *protocol,
255 const struct in6_addr **raddr,
256 const struct in6_addr **laddr,
257 __be16 *rport,
258 __be16 *lport,
259 struct ipv6hdr *ipv6_var)
260 {
261 const struct ipv6hdr *inside_iph;
262 struct icmp6hdr *icmph, _icmph;
263 __be16 *ports, _ports[2];
264 u8 inside_nexthdr;
265 __be16 inside_fragoff;
266 int inside_hdrlen;
267
268 icmph = skb_header_pointer(skb, outside_hdrlen,
269 sizeof(_icmph), &_icmph);
270 if (icmph == NULL)
271 return 1;
272
273 if (icmph->icmp6_type & ICMPV6_INFOMSG_MASK)
274 return 1;
275
276 inside_iph = skb_header_pointer(skb, outside_hdrlen + sizeof(_icmph),
277 sizeof(*ipv6_var), ipv6_var);
278 if (inside_iph == NULL)
279 return 1;
280 inside_nexthdr = inside_iph->nexthdr;
281
282 inside_hdrlen = ipv6_skip_exthdr(skb, outside_hdrlen + sizeof(_icmph) +
283 sizeof(*ipv6_var),
284 &inside_nexthdr, &inside_fragoff);
285 if (inside_hdrlen < 0)
286 return 1; /* hjm: Packet has no/incomplete transport layer headers. */
287
288 if (inside_nexthdr != IPPROTO_TCP &&
289 inside_nexthdr != IPPROTO_UDP)
290 return 1;
291
292 ports = skb_header_pointer(skb, inside_hdrlen,
293 sizeof(_ports), &_ports);
294 if (ports == NULL)
295 return 1;
296
297 /* the inside IP packet is the one quoted from our side, thus
298 * its saddr is the local address */
299 *protocol = inside_nexthdr;
300 *laddr = &inside_iph->saddr;
301 *lport = ports[0];
302 *raddr = &inside_iph->daddr;
303 *rport = ports[1];
304
305 return 0;
306 }
307
308 static struct sock *
309 xt_socket_get_sock_v6(struct net *net, const u8 protocol,
310 const struct in6_addr *saddr, const struct in6_addr *daddr,
311 const __be16 sport, const __be16 dport,
312 const struct net_device *in)
313 {
314 switch (protocol) {
315 case IPPROTO_TCP:
316 return inet6_lookup(net, &tcp_hashinfo,
317 saddr, sport, daddr, dport,
318 in->ifindex);
319 case IPPROTO_UDP:
320 return udp6_lib_lookup(net, saddr, sport, daddr, dport,
321 in->ifindex);
322 }
323
324 return NULL;
325 }
326
327 static bool
328 socket_mt6_v1_v2(const struct sk_buff *skb, struct xt_action_param *par)
329 {
330 struct ipv6hdr ipv6_var, *iph = ipv6_hdr(skb);
331 struct udphdr _hdr, *hp = NULL;
332 struct sock *sk = skb->sk;
333 const struct in6_addr *daddr = NULL, *saddr = NULL;
334 __be16 uninitialized_var(dport), uninitialized_var(sport);
335 int thoff = 0, uninitialized_var(tproto);
336 const struct xt_socket_mtinfo1 *info = (struct xt_socket_mtinfo1 *) par->matchinfo;
337
338 tproto = ipv6_find_hdr(skb, &thoff, -1, NULL, NULL);
339 if (tproto < 0) {
340 pr_debug("unable to find transport header in IPv6 packet, dropping\n");
341 return NF_DROP;
342 }
343
344 if (tproto == IPPROTO_UDP || tproto == IPPROTO_TCP) {
345 hp = skb_header_pointer(skb, thoff,
346 sizeof(_hdr), &_hdr);
347 if (hp == NULL)
348 return false;
349
350 saddr = &iph->saddr;
351 sport = hp->source;
352 daddr = &iph->daddr;
353 dport = hp->dest;
354
355 } else if (tproto == IPPROTO_ICMPV6) {
356 if (extract_icmp6_fields(skb, thoff, &tproto, &saddr, &daddr,
357 &sport, &dport, &ipv6_var))
358 return false;
359 } else {
360 return false;
361 }
362
363 if (!sk)
364 sk = xt_socket_get_sock_v6(dev_net(skb->dev), tproto,
365 saddr, daddr, sport, dport,
366 par->in);
367 if (sk) {
368 bool wildcard;
369 bool transparent = true;
370
371 /* Ignore sockets listening on INADDR_ANY
372 * unless XT_SOCKET_NOWILDCARD is set
373 */
374 wildcard = (!(info->flags & XT_SOCKET_NOWILDCARD) &&
375 sk->sk_state != TCP_TIME_WAIT &&
376 ipv6_addr_any(&inet6_sk(sk)->rcv_saddr));
377
378 /* Ignore non-transparent sockets,
379 if XT_SOCKET_TRANSPARENT is used */
380 if (info->flags & XT_SOCKET_TRANSPARENT)
381 transparent = ((sk->sk_state != TCP_TIME_WAIT &&
382 inet_sk(sk)->transparent) ||
383 (sk->sk_state == TCP_TIME_WAIT &&
384 inet_twsk(sk)->tw_transparent));
385
386 if (sk != skb->sk)
387 xt_socket_put_sk(sk);
388
389 if (wildcard || !transparent)
390 sk = NULL;
391 }
392
393 pr_debug("proto %hhd %pI6:%hu -> %pI6:%hu "
394 "(orig %pI6:%hu) sock %p\n",
395 tproto, saddr, ntohs(sport),
396 daddr, ntohs(dport),
397 &iph->daddr, hp ? ntohs(hp->dest) : 0, sk);
398
399 return (sk != NULL);
400 }
401 #endif
402
403 static int socket_mt_v1_check(const struct xt_mtchk_param *par)
404 {
405 const struct xt_socket_mtinfo1 *info = (struct xt_socket_mtinfo1 *) par->matchinfo;
406
407 if (info->flags & ~XT_SOCKET_FLAGS_V1) {
408 pr_info("unknown flags 0x%x\n", info->flags & ~XT_SOCKET_FLAGS_V1);
409 return -EINVAL;
410 }
411 return 0;
412 }
413
414 static int socket_mt_v2_check(const struct xt_mtchk_param *par)
415 {
416 const struct xt_socket_mtinfo2 *info = (struct xt_socket_mtinfo2 *) par->matchinfo;
417
418 if (info->flags & ~XT_SOCKET_FLAGS_V2) {
419 pr_info("unknown flags 0x%x\n", info->flags & ~XT_SOCKET_FLAGS_V2);
420 return -EINVAL;
421 }
422 return 0;
423 }
424
425 static struct xt_match socket_mt_reg[] __read_mostly = {
426 {
427 .name = "socket",
428 .revision = 0,
429 .family = NFPROTO_IPV4,
430 .match = socket_mt4_v0,
431 .hooks = (1 << NF_INET_PRE_ROUTING) |
432 (1 << NF_INET_LOCAL_IN),
433 .me = THIS_MODULE,
434 },
435 {
436 .name = "socket",
437 .revision = 1,
438 .family = NFPROTO_IPV4,
439 .match = socket_mt4_v1_v2,
440 .checkentry = socket_mt_v1_check,
441 .matchsize = sizeof(struct xt_socket_mtinfo1),
442 .hooks = (1 << NF_INET_PRE_ROUTING) |
443 (1 << NF_INET_LOCAL_IN),
444 .me = THIS_MODULE,
445 },
446 #ifdef XT_SOCKET_HAVE_IPV6
447 {
448 .name = "socket",
449 .revision = 1,
450 .family = NFPROTO_IPV6,
451 .match = socket_mt6_v1_v2,
452 .checkentry = socket_mt_v1_check,
453 .matchsize = sizeof(struct xt_socket_mtinfo1),
454 .hooks = (1 << NF_INET_PRE_ROUTING) |
455 (1 << NF_INET_LOCAL_IN),
456 .me = THIS_MODULE,
457 },
458 #endif
459 {
460 .name = "socket",
461 .revision = 2,
462 .family = NFPROTO_IPV4,
463 .match = socket_mt4_v1_v2,
464 .checkentry = socket_mt_v2_check,
465 .matchsize = sizeof(struct xt_socket_mtinfo1),
466 .hooks = (1 << NF_INET_PRE_ROUTING) |
467 (1 << NF_INET_LOCAL_IN),
468 .me = THIS_MODULE,
469 },
470 #ifdef XT_SOCKET_HAVE_IPV6
471 {
472 .name = "socket",
473 .revision = 2,
474 .family = NFPROTO_IPV6,
475 .match = socket_mt6_v1_v2,
476 .checkentry = socket_mt_v2_check,
477 .matchsize = sizeof(struct xt_socket_mtinfo1),
478 .hooks = (1 << NF_INET_PRE_ROUTING) |
479 (1 << NF_INET_LOCAL_IN),
480 .me = THIS_MODULE,
481 },
482 #endif
483 };
484
485 static int __init socket_mt_init(void)
486 {
487 nf_defrag_ipv4_enable();
488 #ifdef XT_SOCKET_HAVE_IPV6
489 nf_defrag_ipv6_enable();
490 #endif
491
492 return xt_register_matches(socket_mt_reg, ARRAY_SIZE(socket_mt_reg));
493 }
494
495 static void __exit socket_mt_exit(void)
496 {
497 xt_unregister_matches(socket_mt_reg, ARRAY_SIZE(socket_mt_reg));
498 }
499
500 module_init(socket_mt_init);
501 module_exit(socket_mt_exit);
502
503 MODULE_LICENSE("GPL");
504 MODULE_AUTHOR("Krisztian Kovacs, Balazs Scheidler");
505 MODULE_DESCRIPTION("x_tables socket match module");
506 MODULE_ALIAS("ipt_socket");
507 MODULE_ALIAS("ip6t_socket");
Linux with added FPC-III support