1 /* $OpenBSD: addrmatch.c,v 1.9 2014/01/19 11:21:51 dtucker Exp $ */ 2 3 /* 4 * Copyright (c) 2004-2008 Damien Miller <djm@mindrot.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <sys/types.h> 20 #include <sys/socket.h> 21 #include <netinet/in.h> 22 #include <arpa/inet.h> 23 24 #include <netdb.h> 25 #include <string.h> 26 #include <stdlib.h> 27 #include <stdio.h> 28 #include <stdarg.h> 29 30 #include "match.h" 31 #include "log.h" 32 #include "xmalloc.h" 33 34 struct xaddr { 35 sa_family_t af; 36 union { 37 struct in_addr v4; 38 struct in6_addr v6; 39 u_int8_t addr8[16]; 40 u_int32_t addr32[4]; 41 } xa; /* 128-bit address */ 42 u_int32_t scope_id; /* iface scope id for v6 */ 43 #define v4 xa.v4 44 #define v6 xa.v6 45 #define addr8 xa.addr8 46 #define addr32 xa.addr32 47 }; 48 49 static int 50 addr_unicast_masklen(int af) 51 { 52 switch (af) { 53 case AF_INET: 54 return 32; 55 case AF_INET6: 56 return 128; 57 default: 58 return -1; 59 } 60 } 61 62 static inline int 63 masklen_valid(int af, u_int masklen) 64 { 65 switch (af) { 66 case AF_INET: 67 return masklen <= 32 ? 0 : -1; 68 case AF_INET6: 69 return masklen <= 128 ? 0 : -1; 70 default: 71 return -1; 72 } 73 } 74 75 /* 76 * Convert struct sockaddr to struct xaddr 77 * Returns 0 on success, -1 on failure. 78 */ 79 static int 80 addr_sa_to_xaddr(struct sockaddr *sa, socklen_t slen, struct xaddr *xa) 81 { 82 struct sockaddr_in *in4 = (struct sockaddr_in *)sa; 83 struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)sa; 84 85 memset(xa, '\0', sizeof(*xa)); 86 87 switch (sa->sa_family) { 88 case AF_INET: 89 if (slen < (socklen_t)sizeof(*in4)) 90 return -1; 91 xa->af = AF_INET; 92 memcpy(&xa->v4, &in4->sin_addr, sizeof(xa->v4)); 93 break; 94 case AF_INET6: 95 if (slen < (socklen_t)sizeof(*in6)) 96 return -1; 97 xa->af = AF_INET6; 98 memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6)); 99 xa->scope_id = in6->sin6_scope_id; 100 break; 101 default: 102 return -1; 103 } 104 105 return 0; 106 } 107 108 /* 109 * Calculate a netmask of length 'l' for address family 'af' and 110 * store it in 'n'. 111 * Returns 0 on success, -1 on failure. 112 */ 113 static int 114 addr_netmask(int af, u_int l, struct xaddr *n) 115 { 116 int i; 117 118 if (masklen_valid(af, l) != 0 || n == NULL) 119 return -1; 120 121 memset(n, '\0', sizeof(*n)); 122 switch (af) { 123 case AF_INET: 124 n->af = AF_INET; 125 if (l == 0) 126 return 0; 127 n->v4.s_addr = htonl((0xffffffff << (32 - l)) & 0xffffffff); 128 return 0; 129 case AF_INET6: 130 n->af = AF_INET6; 131 for (i = 0; i < 4 && l >= 32; i++, l -= 32) 132 n->addr32[i] = 0xffffffffU; 133 if (i < 4 && l != 0) 134 n->addr32[i] = htonl((0xffffffff << (32 - l)) & 135 0xffffffff); 136 return 0; 137 default: 138 return -1; 139 } 140 } 141 142 /* 143 * Perform logical AND of addresses 'a' and 'b', storing result in 'dst'. 144 * Returns 0 on success, -1 on failure. 145 */ 146 static int 147 addr_and(struct xaddr *dst, const struct xaddr *a, const struct xaddr *b) 148 { 149 int i; 150 151 if (dst == NULL || a == NULL || b == NULL || a->af != b->af) 152 return -1; 153 154 memcpy(dst, a, sizeof(*dst)); 155 switch (a->af) { 156 case AF_INET: 157 dst->v4.s_addr &= b->v4.s_addr; 158 return 0; 159 case AF_INET6: 160 dst->scope_id = a->scope_id; 161 for (i = 0; i < 4; i++) 162 dst->addr32[i] &= b->addr32[i]; 163 return 0; 164 default: 165 return -1; 166 } 167 } 168 169 /* 170 * Compare addresses 'a' and 'b' 171 * Return 0 if addresses are identical, -1 if (a < b) or 1 if (a > b) 172 */ 173 static int 174 addr_cmp(const struct xaddr *a, const struct xaddr *b) 175 { 176 int i; 177 178 if (a->af != b->af) 179 return a->af == AF_INET6 ? 1 : -1; 180 181 switch (a->af) { 182 case AF_INET: 183 if (a->v4.s_addr == b->v4.s_addr) 184 return 0; 185 return ntohl(a->v4.s_addr) > ntohl(b->v4.s_addr) ? 1 : -1; 186 case AF_INET6: 187 for (i = 0; i < 16; i++) 188 if (a->addr8[i] - b->addr8[i] != 0) 189 return a->addr8[i] > b->addr8[i] ? 1 : -1; 190 if (a->scope_id == b->scope_id) 191 return 0; 192 return a->scope_id > b->scope_id ? 1 : -1; 193 default: 194 return -1; 195 } 196 } 197 198 /* 199 * Parse string address 'p' into 'n' 200 * Returns 0 on success, -1 on failure. 201 */ 202 static int 203 addr_pton(const char *p, struct xaddr *n) 204 { 205 struct addrinfo hints, *ai; 206 207 memset(&hints, '\0', sizeof(hints)); 208 hints.ai_flags = AI_NUMERICHOST; 209 210 if (p == NULL || getaddrinfo(p, NULL, &hints, &ai) != 0) 211 return -1; 212 213 if (ai == NULL || ai->ai_addr == NULL) 214 return -1; 215 216 if (n != NULL && 217 addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen, n) == -1) { 218 freeaddrinfo(ai); 219 return -1; 220 } 221 222 freeaddrinfo(ai); 223 return 0; 224 } 225 226 /* 227 * Perform bitwise negation of address 228 * Returns 0 on success, -1 on failure. 229 */ 230 static int 231 addr_invert(struct xaddr *n) 232 { 233 int i; 234 235 if (n == NULL) 236 return (-1); 237 238 switch (n->af) { 239 case AF_INET: 240 n->v4.s_addr = ~n->v4.s_addr; 241 return (0); 242 case AF_INET6: 243 for (i = 0; i < 4; i++) 244 n->addr32[i] = ~n->addr32[i]; 245 return (0); 246 default: 247 return (-1); 248 } 249 } 250 251 /* 252 * Calculate a netmask of length 'l' for address family 'af' and 253 * store it in 'n'. 254 * Returns 0 on success, -1 on failure. 255 */ 256 static int 257 addr_hostmask(int af, u_int l, struct xaddr *n) 258 { 259 if (addr_netmask(af, l, n) == -1 || addr_invert(n) == -1) 260 return (-1); 261 return (0); 262 } 263 264 /* 265 * Test whether address 'a' is all zeros (i.e. 0.0.0.0 or ::) 266 * Returns 0 on if address is all-zeros, -1 if not all zeros or on failure. 267 */ 268 static int 269 addr_is_all0s(const struct xaddr *a) 270 { 271 int i; 272 273 switch (a->af) { 274 case AF_INET: 275 return (a->v4.s_addr == 0 ? 0 : -1); 276 case AF_INET6:; 277 for (i = 0; i < 4; i++) 278 if (a->addr32[i] != 0) 279 return (-1); 280 return (0); 281 default: 282 return (-1); 283 } 284 } 285 286 /* 287 * Test whether host portion of address 'a', as determined by 'masklen' 288 * is all zeros. 289 * Returns 0 on if host portion of address is all-zeros, 290 * -1 if not all zeros or on failure. 291 */ 292 static int 293 addr_host_is_all0s(const struct xaddr *a, u_int masklen) 294 { 295 struct xaddr tmp_addr, tmp_mask, tmp_result; 296 297 memcpy(&tmp_addr, a, sizeof(tmp_addr)); 298 if (addr_hostmask(a->af, masklen, &tmp_mask) == -1) 299 return (-1); 300 if (addr_and(&tmp_result, &tmp_addr, &tmp_mask) == -1) 301 return (-1); 302 return (addr_is_all0s(&tmp_result)); 303 } 304 305 /* 306 * Parse a CIDR address (x.x.x.x/y or xxxx:yyyy::/z). 307 * Return -1 on parse error, -2 on inconsistency or 0 on success. 308 */ 309 static int 310 addr_pton_cidr(const char *p, struct xaddr *n, u_int *l) 311 { 312 struct xaddr tmp; 313 long unsigned int masklen = 999; 314 char addrbuf[64], *mp, *cp; 315 316 /* Don't modify argument */ 317 if (p == NULL || strlcpy(addrbuf, p, sizeof(addrbuf)) >= sizeof(addrbuf)) 318 return -1; 319 320 if ((mp = strchr(addrbuf, '/')) != NULL) { 321 *mp = '\0'; 322 mp++; 323 masklen = strtoul(mp, &cp, 10); 324 if (*mp == '\0' || *cp != '\0' || masklen > 128) 325 return -1; 326 } 327 328 if (addr_pton(addrbuf, &tmp) == -1) 329 return -1; 330 331 if (mp == NULL) 332 masklen = addr_unicast_masklen(tmp.af); 333 if (masklen_valid(tmp.af, masklen) == -1) 334 return -2; 335 if (addr_host_is_all0s(&tmp, masklen) != 0) 336 return -2; 337 338 if (n != NULL) 339 memcpy(n, &tmp, sizeof(*n)); 340 if (l != NULL) 341 *l = masklen; 342 343 return 0; 344 } 345 346 static int 347 addr_netmatch(const struct xaddr *host, const struct xaddr *net, u_int masklen) 348 { 349 struct xaddr tmp_mask, tmp_result; 350 351 if (host->af != net->af) 352 return -1; 353 354 if (addr_netmask(host->af, masklen, &tmp_mask) == -1) 355 return -1; 356 if (addr_and(&tmp_result, host, &tmp_mask) == -1) 357 return -1; 358 return addr_cmp(&tmp_result, net); 359 } 360 361 /* 362 * Match "addr" against list pattern list "_list", which may contain a 363 * mix of CIDR addresses and old-school wildcards. 364 * 365 * If addr is NULL, then no matching is performed, but _list is parsed 366 * and checked for well-formedness. 367 * 368 * Returns 1 on match found (never returned when addr == NULL). 369 * Returns 0 on if no match found, or no errors found when addr == NULL. 370 * Returns -1 on negated match found (never returned when addr == NULL). 371 * Returns -2 on invalid list entry. 372 */ 373 int 374 addr_match_list(const char *addr, const char *_list) 375 { 376 char *list, *cp, *o; 377 struct xaddr try_addr, match_addr; 378 u_int masklen, neg; 379 int ret = 0, r; 380 381 if (addr != NULL && addr_pton(addr, &try_addr) != 0) { 382 debug2("%s: couldn't parse address %.100s", __func__, addr); 383 return 0; 384 } 385 if ((o = list = strdup(_list)) == NULL) 386 return -1; 387 while ((cp = strsep(&list, ",")) != NULL) { 388 neg = *cp == '!'; 389 if (neg) 390 cp++; 391 if (*cp == '\0') { 392 ret = -2; 393 break; 394 } 395 /* Prefer CIDR address matching */ 396 r = addr_pton_cidr(cp, &match_addr, &masklen); 397 if (r == -2) { 398 error("Inconsistent mask length for " 399 "network \"%.100s\"", cp); 400 ret = -2; 401 break; 402 } else if (r == 0) { 403 if (addr != NULL && addr_netmatch(&try_addr, 404 &match_addr, masklen) == 0) { 405 foundit: 406 if (neg) { 407 ret = -1; 408 break; 409 } 410 ret = 1; 411 } 412 continue; 413 } else { 414 /* If CIDR parse failed, try wildcard string match */ 415 if (addr != NULL && match_pattern(addr, cp) == 1) 416 goto foundit; 417 } 418 } 419 free(o); 420 421 return ret; 422 } 423 424 /* 425 * Match "addr" against list CIDR list "_list". Lexical wildcards and 426 * negation are not supported. If "addr" == NULL, will verify structure 427 * of "_list". 428 * 429 * Returns 1 on match found (never returned when addr == NULL). 430 * Returns 0 on if no match found, or no errors found when addr == NULL. 431 * Returns -1 on error 432 */ 433 int 434 addr_match_cidr_list(const char *addr, const char *_list) 435 { 436 char *list, *cp, *o; 437 struct xaddr try_addr, match_addr; 438 u_int masklen; 439 int ret = 0, r; 440 441 if (addr != NULL && addr_pton(addr, &try_addr) != 0) { 442 debug2("%s: couldn't parse address %.100s", __func__, addr); 443 return 0; 444 } 445 if ((o = list = strdup(_list)) == NULL) 446 return -1; 447 while ((cp = strsep(&list, ",")) != NULL) { 448 if (*cp == '\0') { 449 error("%s: empty entry in list \"%.100s\"", 450 __func__, o); 451 ret = -1; 452 break; 453 } 454 455 /* 456 * NB. This function is called in pre-auth with untrusted data, 457 * so be extra paranoid about junk reaching getaddrino (via 458 * addr_pton_cidr). 459 */ 460 461 /* Stop junk from reaching getaddrinfo. +3 is for masklen */ 462 if (strlen(cp) > INET6_ADDRSTRLEN + 3) { 463 error("%s: list entry \"%.100s\" too long", 464 __func__, cp); 465 ret = -1; 466 break; 467 } 468 #define VALID_CIDR_CHARS "0123456789abcdefABCDEF.:/" 469 if (strspn(cp, VALID_CIDR_CHARS) != strlen(cp)) { 470 error("%s: list entry \"%.100s\" contains invalid " 471 "characters", __func__, cp); 472 ret = -1; 473 } 474 475 /* Prefer CIDR address matching */ 476 r = addr_pton_cidr(cp, &match_addr, &masklen); 477 if (r == -1) { 478 error("Invalid network entry \"%.100s\"", cp); 479 ret = -1; 480 break; 481 } else if (r == -2) { 482 error("Inconsistent mask length for " 483 "network \"%.100s\"", cp); 484 ret = -1; 485 break; 486 } else if (r == 0 && addr != NULL) { 487 if (addr_netmatch(&try_addr, &match_addr, 488 masklen) == 0) 489 ret = 1; 490 continue; 491 } 492 } 493 free(o); 494 495 return ret; 496 } 497