1 /* $NetBSD: filter.c,v 1.4 2025/01/07 21:15:40 joe 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 (at) 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 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 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 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 173 do_commit(void) 174 { 175 176 if (ioctl(dev, DIOCXCOMMIT, &pft) == -1) 177 return (-1); 178 179 return (0); 180 } 181 182 int 183 do_rollback(void) 184 { 185 186 if (ioctl(dev, DIOCXROLLBACK, &pft) == -1) 187 return (-1); 188 189 return (0); 190 } 191 192 void 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 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 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 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 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 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
Indexes created Sat Sep 20 22:09:52 GMT 2025