1 /* $OpenBSD: filter.c,v 1.1 2005/12/28 19:07:07 jcs Exp $ */
2 /* $FreeBSD$ */
3
4 /*
5 * Copyright (c) 2004, 2005 Camiel Dobbelaar, <cd@sentia.nl>
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 */
19
20 #include <syslog.h>
21
22 #include <sys/ioctl.h>
23 #include <sys/types.h>
24 #include <sys/socket.h>
25
26 #include <net/if.h>
27 #include <net/pfvar.h>
28 #include <netinet/in.h>
29 #include <netinet/tcp.h>
30 #include <arpa/inet.h>
31
32 #include <err.h>
33 #include <errno.h>
34 #include <fcntl.h>
35 #include <libpfctl.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include <unistd.h>
40
41 #include "filter.h"
42
43 /* From netinet/in.h, but only _KERNEL_ gets them. */
44 #define satosin(sa) ((struct sockaddr_in *)(sa))
45 #define satosin6(sa) ((struct sockaddr_in6 *)(sa))
46
47 enum { TRANS_FILTER = 0, TRANS_NAT, TRANS_RDR, TRANS_SIZE };
48
49 int prepare_rule(u_int32_t, int, struct sockaddr *, struct sockaddr *,
50 u_int16_t, u_int8_t);
51 int server_lookup4(struct sockaddr_in *, struct sockaddr_in *,
52 struct sockaddr_in *, u_int8_t);
53 int server_lookup6(struct sockaddr_in6 *, struct sockaddr_in6 *,
54 struct sockaddr_in6 *, u_int8_t);
55
56 static struct pfioc_pooladdr pfp;
57 static struct pfctl_rule pfrule;
58 static uint32_t pfticket;
59 static uint32_t pfpool_ticket;
60 static char pfanchor[PF_ANCHOR_NAME_SIZE];
61 static char pfanchor_call[PF_ANCHOR_NAME_SIZE];
62 static struct pfioc_trans pft;
63 static struct pfioc_trans_e pfte[TRANS_SIZE];
64 static int dev, rule_log;
65 static char *qname;
66
67 int
add_filter(u_int32_t id,u_int8_t dir,struct sockaddr * src,struct sockaddr * dst,u_int16_t d_port,u_int8_t proto)68 add_filter(u_int32_t id, u_int8_t dir, struct sockaddr *src,
69 struct sockaddr *dst, u_int16_t d_port, u_int8_t proto)
70 {
71 if (!src || !dst || !d_port || !proto) {
72 errno = EINVAL;
73 return (-1);
74 }
75
76 if (prepare_rule(id, PF_RULESET_FILTER, src, dst, d_port, proto) == -1)
77 return (-1);
78
79 pfrule.direction = dir;
80 if (pfctl_add_rule(dev, &pfrule, pfanchor, pfanchor_call,
81 pfticket, pfpool_ticket))
82 return (-1);
83
84 return (0);
85 }
86
87 int
add_nat(u_int32_t id,struct sockaddr * src,struct sockaddr * dst,u_int16_t d_port,struct sockaddr * nat,u_int16_t nat_range_low,u_int16_t nat_range_high,u_int8_t proto)88 add_nat(u_int32_t id, struct sockaddr *src, struct sockaddr *dst,
89 u_int16_t d_port, struct sockaddr *nat, u_int16_t nat_range_low,
90 u_int16_t nat_range_high, u_int8_t proto)
91 {
92 if (!src || !dst || !d_port || !nat || !nat_range_low || !proto ||
93 (src->sa_family != nat->sa_family)) {
94 errno = EINVAL;
95 return (-1);
96 }
97
98 if (prepare_rule(id, PF_RULESET_NAT, src, dst, d_port, proto) == -1)
99 return (-1);
100
101 if (nat->sa_family == AF_INET) {
102 memcpy(&pfp.addr.addr.v.a.addr.v4,
103 &satosin(nat)->sin_addr.s_addr, 4);
104 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 4);
105 } else {
106 memcpy(&pfp.addr.addr.v.a.addr.v6,
107 &satosin6(nat)->sin6_addr.s6_addr, 16);
108 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 16);
109 }
110 if (ioctl(dev, DIOCADDADDR, &pfp) == -1)
111 return (-1);
112
113 pfrule.rpool.proxy_port[0] = nat_range_low;
114 pfrule.rpool.proxy_port[1] = nat_range_high;
115 if (pfctl_add_rule(dev, &pfrule, pfanchor, pfanchor_call,
116 pfticket, pfpool_ticket))
117 return (-1);
118
119 return (0);
120 }
121
122 int
add_rdr(u_int32_t id,struct sockaddr * src,struct sockaddr * dst,u_int16_t d_port,struct sockaddr * rdr,u_int16_t rdr_port,u_int8_t proto)123 add_rdr(u_int32_t id, struct sockaddr *src, struct sockaddr *dst,
124 u_int16_t d_port, struct sockaddr *rdr, u_int16_t rdr_port, u_int8_t proto)
125 {
126 if (!src || !dst || !d_port || !rdr || !rdr_port || !proto ||
127 (src->sa_family != rdr->sa_family)) {
128 errno = EINVAL;
129 return (-1);
130 }
131
132 if (prepare_rule(id, PF_RULESET_RDR, src, dst, d_port, proto) == -1)
133 return (-1);
134
135 if (rdr->sa_family == AF_INET) {
136 memcpy(&pfp.addr.addr.v.a.addr.v4,
137 &satosin(rdr)->sin_addr.s_addr, 4);
138 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 4);
139 } else {
140 memcpy(&pfp.addr.addr.v.a.addr.v6,
141 &satosin6(rdr)->sin6_addr.s6_addr, 16);
142 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 16);
143 }
144 if (ioctl(dev, DIOCADDADDR, &pfp) == -1)
145 return (-1);
146
147 pfrule.rpool.proxy_port[0] = rdr_port;
148 if (pfctl_add_rule(dev, &pfrule, pfanchor, pfanchor_call,
149 pfticket, pfpool_ticket))
150 return (-1);
151
152 return (0);
153 }
154
155 int
do_commit(void)156 do_commit(void)
157 {
158 if (ioctl(dev, DIOCXCOMMIT, &pft) == -1)
159 return (-1);
160
161 return (0);
162 }
163
164 int
do_rollback(void)165 do_rollback(void)
166 {
167 if (ioctl(dev, DIOCXROLLBACK, &pft) == -1)
168 return (-1);
169
170 return (0);
171 }
172
173 void
init_filter(char * opt_qname,int opt_verbose)174 init_filter(char *opt_qname, int opt_verbose)
175 {
176 struct pfctl_status *status;
177
178 qname = opt_qname;
179
180 if (opt_verbose == 1)
181 rule_log = PF_LOG;
182 else if (opt_verbose == 2)
183 rule_log = PF_LOG_ALL;
184
185 dev = open("/dev/pf", O_RDWR);
186 if (dev == -1) {
187 syslog(LOG_ERR, "can't open /dev/pf");
188 exit(1);
189 }
190 status = pfctl_get_status(dev);
191 if (status == NULL) {
192 syslog(LOG_ERR, "DIOCGETSTATUS");
193 exit(1);
194 }
195 if (!status->running) {
196 syslog(LOG_ERR, "pf is disabled");
197 exit(1);
198 }
199
200 pfctl_free_status(status);
201 }
202
203 int
prepare_commit(u_int32_t id)204 prepare_commit(u_int32_t id)
205 {
206 char an[PF_ANCHOR_NAME_SIZE];
207 int i;
208
209 memset(&pft, 0, sizeof pft);
210 pft.size = TRANS_SIZE;
211 pft.esize = sizeof pfte[0];
212 pft.array = pfte;
213
214 snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR,
215 getpid(), id);
216 for (i = 0; i < TRANS_SIZE; i++) {
217 memset(&pfte[i], 0, sizeof pfte[0]);
218 strlcpy(pfte[i].anchor, an, PF_ANCHOR_NAME_SIZE);
219 switch (i) {
220 case TRANS_FILTER:
221 pfte[i].rs_num = PF_RULESET_FILTER;
222 break;
223 case TRANS_NAT:
224 pfte[i].rs_num = PF_RULESET_NAT;
225 break;
226 case TRANS_RDR:
227 pfte[i].rs_num = PF_RULESET_RDR;
228 break;
229 default:
230 errno = EINVAL;
231 return (-1);
232 }
233 }
234
235 if (ioctl(dev, DIOCXBEGIN, &pft) == -1)
236 return (-1);
237
238 return (0);
239 }
240
241 int
prepare_rule(u_int32_t id,int rs_num,struct sockaddr * src,struct sockaddr * dst,u_int16_t d_port,u_int8_t proto)242 prepare_rule(u_int32_t id, int rs_num, struct sockaddr *src,
243 struct sockaddr *dst, u_int16_t d_port, u_int8_t proto)
244 {
245 char an[PF_ANCHOR_NAME_SIZE];
246
247 if ((src->sa_family != AF_INET && src->sa_family != AF_INET6) ||
248 (src->sa_family != dst->sa_family)) {
249 errno = EPROTONOSUPPORT;
250 return (-1);
251 }
252
253 memset(&pfp, 0, sizeof pfp);
254 memset(&pfrule, 0, sizeof pfrule);
255 snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR,
256 getpid(), id);
257 strlcpy(pfp.anchor, an, PF_ANCHOR_NAME_SIZE);
258 strlcpy(pfanchor, an, PF_ANCHOR_NAME_SIZE);
259
260 switch (rs_num) {
261 case PF_RULESET_FILTER:
262 pfticket = pfte[TRANS_FILTER].ticket;
263 break;
264 case PF_RULESET_NAT:
265 pfticket = pfte[TRANS_NAT].ticket;
266 break;
267 case PF_RULESET_RDR:
268 pfticket = pfte[TRANS_RDR].ticket;
269 break;
270 default:
271 errno = EINVAL;
272 return (-1);
273 }
274 if (ioctl(dev, DIOCBEGINADDRS, &pfp) == -1)
275 return (-1);
276 pfpool_ticket = pfp.ticket;
277
278 /* Generic for all rule types. */
279 pfrule.af = src->sa_family;
280 pfrule.proto = proto;
281 pfrule.src.addr.type = PF_ADDR_ADDRMASK;
282 pfrule.dst.addr.type = PF_ADDR_ADDRMASK;
283 if (src->sa_family == AF_INET) {
284 memcpy(&pfrule.src.addr.v.a.addr.v4,
285 &satosin(src)->sin_addr.s_addr, 4);
286 memset(&pfrule.src.addr.v.a.mask.addr8, 255, 4);
287 memcpy(&pfrule.dst.addr.v.a.addr.v4,
288 &satosin(dst)->sin_addr.s_addr, 4);
289 memset(&pfrule.dst.addr.v.a.mask.addr8, 255, 4);
290 } else {
291 memcpy(&pfrule.src.addr.v.a.addr.v6,
292 &satosin6(src)->sin6_addr.s6_addr, 16);
293 memset(&pfrule.src.addr.v.a.mask.addr8, 255, 16);
294 memcpy(&pfrule.dst.addr.v.a.addr.v6,
295 &satosin6(dst)->sin6_addr.s6_addr, 16);
296 memset(&pfrule.dst.addr.v.a.mask.addr8, 255, 16);
297 }
298 pfrule.dst.port_op = PF_OP_EQ;
299 pfrule.dst.port[0] = htons(d_port);
300
301 switch (rs_num) {
302 case PF_RULESET_FILTER:
303 /*
304 * pass quick [log] inet[6] proto tcp \
305 * from $src to $dst port = $d_port flags S/SAFR keep state
306 * (max 1) [queue qname]
307 */
308 pfrule.action = PF_PASS;
309 pfrule.quick = 1;
310 pfrule.log = rule_log;
311 pfrule.keep_state = 1;
312 #ifdef __FreeBSD__
313 pfrule.flags = (proto == IPPROTO_TCP ? TH_SYN : 0);
314 pfrule.flagset = (proto == IPPROTO_TCP ?
315 (TH_SYN|TH_ACK|TH_FIN|TH_RST) : 0);
316 #else
317 pfrule.flags = (proto == IPPROTO_TCP ? TH_SYN : NULL);
318 pfrule.flagset = (proto == IPPROTO_TCP ?
319 (TH_SYN|TH_ACK|TH_FIN|TH_RST) : NULL);
320 #endif
321 pfrule.max_states = 1;
322 if (qname != NULL)
323 strlcpy(pfrule.qname, qname, sizeof pfrule.qname);
324 break;
325 case PF_RULESET_NAT:
326 /*
327 * nat inet[6] proto tcp from $src to $dst port $d_port -> $nat
328 */
329 pfrule.action = PF_NAT;
330 break;
331 case PF_RULESET_RDR:
332 /*
333 * rdr inet[6] proto tcp from $src to $dst port $d_port -> $rdr
334 */
335 pfrule.action = PF_RDR;
336 break;
337 default:
338 errno = EINVAL;
339 return (-1);
340 }
341
342 return (0);
343 }
344
345 int
server_lookup(struct sockaddr * client,struct sockaddr * proxy,struct sockaddr * server,u_int8_t proto)346 server_lookup(struct sockaddr *client, struct sockaddr *proxy,
347 struct sockaddr *server, u_int8_t proto)
348 {
349 if (client->sa_family == AF_INET)
350 return (server_lookup4(satosin(client), satosin(proxy),
351 satosin(server), proto));
352
353 if (client->sa_family == AF_INET6)
354 return (server_lookup6(satosin6(client), satosin6(proxy),
355 satosin6(server), proto));
356
357 errno = EPROTONOSUPPORT;
358 return (-1);
359 }
360
361 int
server_lookup4(struct sockaddr_in * client,struct sockaddr_in * proxy,struct sockaddr_in * server,u_int8_t proto)362 server_lookup4(struct sockaddr_in *client, struct sockaddr_in *proxy,
363 struct sockaddr_in *server, u_int8_t proto)
364 {
365 struct pfioc_natlook pnl;
366
367 memset(&pnl, 0, sizeof pnl);
368 pnl.direction = PF_OUT;
369 pnl.af = AF_INET;
370 pnl.proto = proto;
371 memcpy(&pnl.saddr.v4, &client->sin_addr.s_addr, sizeof pnl.saddr.v4);
372 memcpy(&pnl.daddr.v4, &proxy->sin_addr.s_addr, sizeof pnl.daddr.v4);
373 pnl.sport = client->sin_port;
374 pnl.dport = proxy->sin_port;
375
376 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1)
377 return (-1);
378
379 memset(server, 0, sizeof(struct sockaddr_in));
380 server->sin_len = sizeof(struct sockaddr_in);
381 server->sin_family = AF_INET;
382 memcpy(&server->sin_addr.s_addr, &pnl.rdaddr.v4,
383 sizeof server->sin_addr.s_addr);
384 server->sin_port = pnl.rdport;
385
386 return (0);
387 }
388
389 int
server_lookup6(struct sockaddr_in6 * client,struct sockaddr_in6 * proxy,struct sockaddr_in6 * server,u_int8_t proto)390 server_lookup6(struct sockaddr_in6 *client, struct sockaddr_in6 *proxy,
391 struct sockaddr_in6 *server, u_int8_t proto)
392 {
393 struct pfioc_natlook pnl;
394
395 memset(&pnl, 0, sizeof pnl);
396 pnl.direction = PF_OUT;
397 pnl.af = AF_INET6;
398 pnl.proto = proto;
399 memcpy(&pnl.saddr.v6, &client->sin6_addr.s6_addr, sizeof pnl.saddr.v6);
400 memcpy(&pnl.daddr.v6, &proxy->sin6_addr.s6_addr, sizeof pnl.daddr.v6);
401 pnl.sport = client->sin6_port;
402 pnl.dport = proxy->sin6_port;
403
404 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1)
405 return (-1);
406
407 memset(server, 0, sizeof(struct sockaddr_in6));
408 server->sin6_len = sizeof(struct sockaddr_in6);
409 server->sin6_family = AF_INET6;
410 memcpy(&server->sin6_addr.s6_addr, &pnl.rdaddr.v6,
411 sizeof server->sin6_addr);
412 server->sin6_port = pnl.rdport;
413
414 return (0);
415 }
416