1 /* $NetBSD: filter.c,v 1.3 2011/02/02 02:20:26 rmind Exp $ */
2 /* $OpenBSD: filter.c,v 1.6 2007/08/01 09:31:41 henning Exp $ */
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 <sys/ioctl.h>
21 #include <sys/types.h>
22 #include <sys/socket.h>
23
24 #include <net/if.h>
25 #include <net/pfvar.h>
26 #include <netinet/in.h>
27 #include <netinet/tcp.h>
28 #include <arpa/inet.h>
29
30 #include <err.h>
31 #include <errno.h>
32 #include <fcntl.h>
33 #include <stdio.h>
34 #include <string.h>
35 #include <unistd.h>
36
37 #include "filter.h"
38
39 /* From netinet/in.h, but only _KERNEL_ gets them. */
40 #define satosin(sa) ((struct sockaddr_in *)(sa))
41 #define satosin6(sa) ((struct sockaddr_in6 *)(sa))
42
43 #define FTP_PROXY_ANCHOR "ftp-proxy"
44
45 enum { TRANS_FILTER = 0, TRANS_NAT, TRANS_RDR, TRANS_SIZE };
46
47 int add_filter(u_int32_t, u_int8_t, struct sockaddr *, struct sockaddr *,
48 u_int16_t);
49 int add_nat(u_int32_t, struct sockaddr *, struct sockaddr *, u_int16_t,
50 struct sockaddr *, u_int16_t, u_int16_t);
51 int add_rdr(u_int32_t, struct sockaddr *, struct sockaddr *, u_int16_t,
52 struct sockaddr *, u_int16_t);
53 int do_commit(void);
54 int do_rollback(void);
55 void init_filter(char *, char *, int);
56 int prepare_commit(u_int32_t);
57 int server_lookup(struct sockaddr *, struct sockaddr *, struct sockaddr *);
58
59 int prepare_rule(u_int32_t, int, struct sockaddr *, struct sockaddr *,
60 u_int16_t);
61 int server_lookup4(struct sockaddr_in *, struct sockaddr_in *,
62 struct sockaddr_in *);
63 int server_lookup6(struct sockaddr_in6 *, struct sockaddr_in6 *,
64 struct sockaddr_in6 *);
65
66 static struct pfioc_pooladdr pfp;
67 static struct pfioc_rule pfr;
68 static struct pfioc_trans pft;
69 static struct pfioc_trans_e pfte[TRANS_SIZE];
70 static int dev, rule_log;
71 static char *qname, *tagname;
72
73 const ftp_proxy_ops_t pf_fprx_ops = {
74 .init_filter = init_filter,
75 .add_filter = add_filter,
76 .add_nat = add_nat,
77 .add_rdr = add_rdr,
78 .server_lookup = server_lookup,
79 .prepare_commit = prepare_commit,
80 .do_commit = do_commit,
81 .do_rollback = do_rollback
82 };
83
84 int
add_filter(u_int32_t id,u_int8_t dir,struct sockaddr * src,struct sockaddr * dst,u_int16_t d_port)85 add_filter(u_int32_t id, u_int8_t dir, struct sockaddr *src,
86 struct sockaddr *dst, u_int16_t d_port)
87 {
88
89 if (!src || !dst || !d_port) {
90 errno = EINVAL;
91 return (-1);
92 }
93
94 if (prepare_rule(id, PF_RULESET_FILTER, src, dst, d_port) == -1)
95 return (-1);
96
97 pfr.rule.direction = dir;
98 if (ioctl(dev, DIOCADDRULE, &pfr) == -1)
99 return (-1);
100
101 return (0);
102 }
103
104 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)105 add_nat(u_int32_t id, struct sockaddr *src, struct sockaddr *dst,
106 u_int16_t d_port, struct sockaddr *nat, u_int16_t nat_range_low,
107 u_int16_t nat_range_high)
108 {
109
110 if (!src || !dst || !d_port || !nat || !nat_range_low ||
111 (src->sa_family != nat->sa_family)) {
112 errno = EINVAL;
113 return (-1);
114 }
115
116 if (prepare_rule(id, PF_RULESET_NAT, src, dst, d_port) == -1)
117 return (-1);
118
119 if (nat->sa_family == AF_INET) {
120 memcpy(&pfp.addr.addr.v.a.addr.v4,
121 &satosin(nat)->sin_addr.s_addr, 4);
122 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 4);
123 } else {
124 memcpy(&pfp.addr.addr.v.a.addr.v6,
125 &satosin6(nat)->sin6_addr.s6_addr, 16);
126 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 16);
127 }
128 if (ioctl(dev, DIOCADDADDR, &pfp) == -1)
129 return (-1);
130
131 pfr.rule.rpool.proxy_port[0] = nat_range_low;
132 pfr.rule.rpool.proxy_port[1] = nat_range_high;
133 if (ioctl(dev, DIOCADDRULE, &pfr) == -1)
134 return (-1);
135
136 return (0);
137 }
138
139 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)140 add_rdr(u_int32_t id, struct sockaddr *src, struct sockaddr *dst,
141 u_int16_t d_port, struct sockaddr *rdr, u_int16_t rdr_port)
142 {
143
144 if (!src || !dst || !d_port || !rdr || !rdr_port ||
145 (src->sa_family != rdr->sa_family)) {
146 errno = EINVAL;
147 return (-1);
148 }
149
150 if (prepare_rule(id, PF_RULESET_RDR, src, dst, d_port) == -1)
151 return (-1);
152
153 if (rdr->sa_family == AF_INET) {
154 memcpy(&pfp.addr.addr.v.a.addr.v4,
155 &satosin(rdr)->sin_addr.s_addr, 4);
156 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 4);
157 } else {
158 memcpy(&pfp.addr.addr.v.a.addr.v6,
159 &satosin6(rdr)->sin6_addr.s6_addr, 16);
160 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 16);
161 }
162 if (ioctl(dev, DIOCADDADDR, &pfp) == -1)
163 return (-1);
164
165 pfr.rule.rpool.proxy_port[0] = rdr_port;
166 if (ioctl(dev, DIOCADDRULE, &pfr) == -1)
167 return (-1);
168
169 return (0);
170 }
171
172 int
do_commit(void)173 do_commit(void)
174 {
175
176 if (ioctl(dev, DIOCXCOMMIT, &pft) == -1)
177 return (-1);
178
179 return (0);
180 }
181
182 int
do_rollback(void)183 do_rollback(void)
184 {
185
186 if (ioctl(dev, DIOCXROLLBACK, &pft) == -1)
187 return (-1);
188
189 return (0);
190 }
191
192 void
init_filter(char * opt_qname,char * opt_tagname,int opt_verbose)193 init_filter(char *opt_qname, char *opt_tagname, int opt_verbose)
194 {
195 struct pf_status status;
196
197 qname = opt_qname;
198 tagname = opt_tagname;
199
200 if (opt_verbose == 1)
201 rule_log = PF_LOG;
202 else if (opt_verbose == 2)
203 rule_log = PF_LOG_ALL;
204
205 dev = open("/dev/pf", O_RDWR);
206 if (dev == -1)
207 err(1, "/dev/pf");
208 if (ioctl(dev, DIOCGETSTATUS, &status) == -1)
209 err(1, "DIOCGETSTATUS");
210 if (!status.running)
211 errx(1, "pf is disabled");
212 }
213
214 int
prepare_commit(u_int32_t id)215 prepare_commit(u_int32_t id)
216 {
217 char an[PF_ANCHOR_NAME_SIZE];
218 int i;
219
220 memset(&pft, 0, sizeof pft);
221 pft.size = TRANS_SIZE;
222 pft.esize = sizeof pfte[0];
223 pft.array = pfte;
224
225 snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR,
226 getpid(), id);
227 for (i = 0; i < TRANS_SIZE; i++) {
228 memset(&pfte[i], 0, sizeof pfte[0]);
229 strlcpy(pfte[i].anchor, an, PF_ANCHOR_NAME_SIZE);
230 switch (i) {
231 case TRANS_FILTER:
232 pfte[i].rs_num = PF_RULESET_FILTER;
233 break;
234 case TRANS_NAT:
235 pfte[i].rs_num = PF_RULESET_NAT;
236 break;
237 case TRANS_RDR:
238 pfte[i].rs_num = PF_RULESET_RDR;
239 break;
240 default:
241 errno = EINVAL;
242 return (-1);
243 }
244 }
245
246 if (ioctl(dev, DIOCXBEGIN, &pft) == -1)
247 return (-1);
248
249 return (0);
250 }
251
252 int
prepare_rule(u_int32_t id,int rs_num,struct sockaddr * src,struct sockaddr * dst,u_int16_t d_port)253 prepare_rule(u_int32_t id, int rs_num, struct sockaddr *src,
254 struct sockaddr *dst, u_int16_t d_port)
255 {
256 char an[PF_ANCHOR_NAME_SIZE];
257
258 if ((src->sa_family != AF_INET && src->sa_family != AF_INET6) ||
259 (src->sa_family != dst->sa_family)) {
260 errno = EPROTONOSUPPORT;
261 return (-1);
262 }
263
264 memset(&pfp, 0, sizeof pfp);
265 memset(&pfr, 0, sizeof pfr);
266 snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR,
267 getpid(), id);
268 strlcpy(pfp.anchor, an, PF_ANCHOR_NAME_SIZE);
269 strlcpy(pfr.anchor, an, PF_ANCHOR_NAME_SIZE);
270
271 switch (rs_num) {
272 case PF_RULESET_FILTER:
273 pfr.ticket = pfte[TRANS_FILTER].ticket;
274 break;
275 case PF_RULESET_NAT:
276 pfr.ticket = pfte[TRANS_NAT].ticket;
277 break;
278 case PF_RULESET_RDR:
279 pfr.ticket = pfte[TRANS_RDR].ticket;
280 break;
281 default:
282 errno = EINVAL;
283 return (-1);
284 }
285 if (ioctl(dev, DIOCBEGINADDRS, &pfp) == -1)
286 return (-1);
287 pfr.pool_ticket = pfp.ticket;
288
289 /* Generic for all rule types. */
290 pfr.rule.af = src->sa_family;
291 pfr.rule.proto = IPPROTO_TCP;
292 pfr.rule.src.addr.type = PF_ADDR_ADDRMASK;
293 pfr.rule.dst.addr.type = PF_ADDR_ADDRMASK;
294 if (src->sa_family == AF_INET) {
295 memcpy(&pfr.rule.src.addr.v.a.addr.v4,
296 &satosin(src)->sin_addr.s_addr, 4);
297 memset(&pfr.rule.src.addr.v.a.mask.addr8, 255, 4);
298 memcpy(&pfr.rule.dst.addr.v.a.addr.v4,
299 &satosin(dst)->sin_addr.s_addr, 4);
300 memset(&pfr.rule.dst.addr.v.a.mask.addr8, 255, 4);
301 } else {
302 memcpy(&pfr.rule.src.addr.v.a.addr.v6,
303 &satosin6(src)->sin6_addr.s6_addr, 16);
304 memset(&pfr.rule.src.addr.v.a.mask.addr8, 255, 16);
305 memcpy(&pfr.rule.dst.addr.v.a.addr.v6,
306 &satosin6(dst)->sin6_addr.s6_addr, 16);
307 memset(&pfr.rule.dst.addr.v.a.mask.addr8, 255, 16);
308 }
309 pfr.rule.dst.port_op = PF_OP_EQ;
310 pfr.rule.dst.port[0] = htons(d_port);
311 if (tagname != NULL)
312 strlcpy(pfr.rule.tagname, tagname, sizeof pfr.rule.tagname);
313
314 switch (rs_num) {
315 case PF_RULESET_FILTER:
316 /*
317 * pass quick [log] inet[6] proto tcp \
318 * from $src to $dst port = $d_port flags S/SA keep state
319 * (max 1) [queue qname]
320 */
321 pfr.rule.action = PF_PASS;
322 pfr.rule.quick = 1;
323 pfr.rule.log = rule_log;
324 pfr.rule.keep_state = 1;
325 pfr.rule.flags = TH_SYN;
326 pfr.rule.flagset = (TH_SYN|TH_ACK);
327 pfr.rule.max_states = 1;
328 if (qname != NULL)
329 strlcpy(pfr.rule.qname, qname, sizeof pfr.rule.qname);
330 break;
331 case PF_RULESET_NAT:
332 /*
333 * nat inet[6] proto tcp from $src to $dst port $d_port -> $nat
334 */
335 pfr.rule.action = PF_NAT;
336 break;
337 case PF_RULESET_RDR:
338 /*
339 * rdr inet[6] proto tcp from $src to $dst port $d_port -> $rdr
340 */
341 pfr.rule.action = PF_RDR;
342 break;
343 default:
344 errno = EINVAL;
345 return (-1);
346 }
347
348 return (0);
349 }
350
351 int
server_lookup(struct sockaddr * client,struct sockaddr * proxy,struct sockaddr * server)352 server_lookup(struct sockaddr *client, struct sockaddr *proxy,
353 struct sockaddr *server)
354 {
355
356 if (client->sa_family == AF_INET)
357 return (server_lookup4(satosin(client), satosin(proxy),
358 satosin(server)));
359
360 if (client->sa_family == AF_INET6)
361 return (server_lookup6(satosin6(client), satosin6(proxy),
362 satosin6(server)));
363
364 errno = EPROTONOSUPPORT;
365 return (-1);
366 }
367
368 int
server_lookup4(struct sockaddr_in * client,struct sockaddr_in * proxy,struct sockaddr_in * server)369 server_lookup4(struct sockaddr_in *client, struct sockaddr_in *proxy,
370 struct sockaddr_in *server)
371 {
372 struct pfioc_natlook pnl;
373
374 memset(&pnl, 0, sizeof pnl);
375 pnl.direction = PF_OUT;
376 pnl.af = AF_INET;
377 pnl.proto = IPPROTO_TCP;
378 memcpy(&pnl.saddr.v4, &client->sin_addr.s_addr, sizeof pnl.saddr.v4);
379 memcpy(&pnl.daddr.v4, &proxy->sin_addr.s_addr, sizeof pnl.daddr.v4);
380 pnl.sport = client->sin_port;
381 pnl.dport = proxy->sin_port;
382
383 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1)
384 return (-1);
385
386 memset(server, 0, sizeof(struct sockaddr_in));
387 server->sin_len = sizeof(struct sockaddr_in);
388 server->sin_family = AF_INET;
389 memcpy(&server->sin_addr.s_addr, &pnl.rdaddr.v4,
390 sizeof server->sin_addr.s_addr);
391 server->sin_port = pnl.rdport;
392
393 return (0);
394 }
395
396 int
server_lookup6(struct sockaddr_in6 * client,struct sockaddr_in6 * proxy,struct sockaddr_in6 * server)397 server_lookup6(struct sockaddr_in6 *client, struct sockaddr_in6 *proxy,
398 struct sockaddr_in6 *server)
399 {
400 struct pfioc_natlook pnl;
401
402 memset(&pnl, 0, sizeof pnl);
403 pnl.direction = PF_OUT;
404 pnl.af = AF_INET6;
405 pnl.proto = IPPROTO_TCP;
406 memcpy(&pnl.saddr.v6, &client->sin6_addr.s6_addr, sizeof pnl.saddr.v6);
407 memcpy(&pnl.daddr.v6, &proxy->sin6_addr.s6_addr, sizeof pnl.daddr.v6);
408 pnl.sport = client->sin6_port;
409 pnl.dport = proxy->sin6_port;
410
411 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1)
412 return (-1);
413
414 memset(server, 0, sizeof(struct sockaddr_in6));
415 server->sin6_len = sizeof(struct sockaddr_in6);
416 server->sin6_family = AF_INET6;
417 memcpy(&server->sin6_addr.s6_addr, &pnl.rdaddr.v6,
418 sizeof server->sin6_addr);
419 server->sin6_port = pnl.rdport;
420
421 return (0);
422 }
423