1 /* $OpenBSD: addrmatch.c,v 1.13 2016/09/21 16:55:42 djm 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 33 struct xaddr { 34 sa_family_t af; 35 union { 36 struct in_addr v4; 37 struct in6_addr v6; 38 u_int8_t addr8[16]; 39 u_int32_t addr32[4]; 40 } xa; /* 128-bit address */ 41 u_int32_t scope_id; /* iface scope id for v6 */ 42 #define v4 xa.v4 43 #define v6 xa.v6 44 #define addr8 xa.addr8 45 #define addr32 xa.addr32 46 }; 47 48 static int 49 addr_unicast_masklen(int af) 50 { 51 switch (af) { 52 case AF_INET: 53 return 32; 54 case AF_INET6: 55 return 128; 56 default: 57 return -1; 58 } 59 } 60 61 static inline int 62 masklen_valid(int af, u_int masklen) 63 { 64 switch (af) { 65 case AF_INET: 66 return masklen <= 32 ? 0 : -1; 67 case AF_INET6: 68 return masklen <= 128 ? 0 : -1; 69 default: 70 return -1; 71 } 72 } 73 74 /* 75 * Convert struct sockaddr to struct xaddr 76 * Returns 0 on success, -1 on failure. 77 */ 78 static int 79 addr_sa_to_xaddr(struct sockaddr *sa, socklen_t slen, struct xaddr *xa) 80 { 81 struct sockaddr_in *in4 = (struct sockaddr_in *)sa; 82 struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)sa; 83 84 memset(xa, '\0', sizeof(*xa)); 85 86 switch (sa->sa_family) { 87 case AF_INET: 88 if (slen < (socklen_t)sizeof(*in4)) 89 return -1; 90 xa->af = AF_INET; 91 memcpy(&xa->v4, &in4->sin_addr, sizeof(xa->v4)); 92 break; 93 case AF_INET6: 94 if (slen < (socklen_t)sizeof(*in6)) 95 return -1; 96 xa->af = AF_INET6; 97 memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6)); 98 xa->scope_id = in6->sin6_scope_id; 99 break; 100 default: 101 return -1; 102 } 103 104 return 0; 105 } 106 107 /* 108 * Calculate a netmask of length 'l' for address family 'af' and 109 * store it in 'n'. 110 * Returns 0 on success, -1 on failure. 111 */ 112 static int 113 addr_netmask(int af, u_int l, struct xaddr *n) 114 { 115 int i; 116 117 if (masklen_valid(af, l) != 0 || n == NULL) 118 return -1; 119 120 memset(n, '\0', sizeof(*n)); 121 switch (af) { 122 case AF_INET: 123 n->af = AF_INET; 124 if (l == 0) 125 return 0; 126 n->v4.s_addr = htonl((0xffffffff << (32 - l)) & 0xffffffff); 127 return 0; 128 case AF_INET6: 129 n->af = AF_INET6; 130 for (i = 0; i < 4 && l >= 32; i++, l -= 32) 131 n->addr32[i] = 0xffffffffU; 132 if (i < 4 && l != 0) 133 n->addr32[i] = htonl((0xffffffff << (32 - l)) & 134 0xffffffff); 135 return 0; 136 default: 137 return -1; 138 } 139 } 140 141 /* 142 * Perform logical AND of addresses 'a' and 'b', storing result in 'dst'. 143 * Returns 0 on success, -1 on failure. 144 */ 145 static int 146 addr_and(struct xaddr *dst, const struct xaddr *a, const struct xaddr *b) 147 { 148 int i; 149 150 if (dst == NULL || a == NULL || b == NULL || a->af != b->af) 151 return -1; 152 153 memcpy(dst, a, sizeof(*dst)); 154 switch (a->af) { 155 case AF_INET: 156 dst->v4.s_addr &= b->v4.s_addr; 157 return 0; 158 case AF_INET6: 159 dst->scope_id = a->scope_id; 160 for (i = 0; i < 4; i++) 161 dst->addr32[i] &= b->addr32[i]; 162 return 0; 163 default: 164 return -1; 165 } 166 } 167 168 /* 169 * Compare addresses 'a' and 'b' 170 * Return 0 if addresses are identical, -1 if (a < b) or 1 if (a > b) 171 */ 172 static int 173 addr_cmp(const struct xaddr *a, const struct xaddr *b) 174 { 175 int i; 176 177 if (a->af != b->af) 178 return a->af == AF_INET6 ? 1 : -1; 179 180 switch (a->af) { 181 case AF_INET: 182 if (a->v4.s_addr == b->v4.s_addr) 183 return 0; 184 return ntohl(a->v4.s_addr) > ntohl(b->v4.s_addr) ? 1 : -1; 185 case AF_INET6: 186 for (i = 0; i < 16; i++) 187 if (a->addr8[i] - b->addr8[i] != 0) 188 return a->addr8[i] > b->addr8[i] ? 1 : -1; 189 if (a->scope_id == b->scope_id) 190 return 0; 191 return a->scope_id > b->scope_id ? 1 : -1; 192 default: 193 return -1; 194 } 195 } 196 197 /* 198 * Parse string address 'p' into 'n' 199 * Returns 0 on success, -1 on failure. 200 */ 201 static int 202 addr_pton(const char *p, struct xaddr *n) 203 { 204 struct addrinfo hints, *ai; 205 206 memset(&hints, '\0', sizeof(hints)); 207 hints.ai_flags = AI_NUMERICHOST; 208 209 if (p == NULL || getaddrinfo(p, NULL, &hints, &ai) != 0) 210 return -1; 211 212 if (ai == NULL || ai->ai_addr == NULL) 213 return -1; 214 215 if (n != NULL && 216 addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen, n) == -1) { 217 freeaddrinfo(ai); 218 return -1; 219 } 220 221 freeaddrinfo(ai); 222 return 0; 223 } 224 225 /* 226 * Perform bitwise negation of address 227 * Returns 0 on success, -1 on failure. 228 */ 229 static int 230 addr_invert(struct xaddr *n) 231 { 232 int i; 233 234 if (n == NULL) 235 return (-1); 236 237 switch (n->af) { 238 case AF_INET: 239 n->v4.s_addr = ~n->v4.s_addr; 240 return (0); 241 case AF_INET6: 242 for (i = 0; i < 4; i++) 243 n->addr32[i] = ~n->addr32[i]; 244 return (0); 245 default: 246 return (-1); 247 } 248 } 249 250 /* 251 * Calculate a netmask of length 'l' for address family 'af' and 252 * store it in 'n'. 253 * Returns 0 on success, -1 on failure. 254 */ 255 static int 256 addr_hostmask(int af, u_int l, struct xaddr *n) 257 { 258 if (addr_netmask(af, l, n) == -1 || addr_invert(n) == -1) 259 return (-1); 260 return (0); 261 } 262 263 /* 264 * Test whether address 'a' is all zeros (i.e. 0.0.0.0 or ::) 265 * Returns 0 on if address is all-zeros, -1 if not all zeros or on failure. 266 */ 267 static int 268 addr_is_all0s(const struct xaddr *a) 269 { 270 int i; 271 272 switch (a->af) { 273 case AF_INET: 274 return (a->v4.s_addr == 0 ? 0 : -1); 275 case AF_INET6:; 276 for (i = 0; i < 4; i++) 277 if (a->addr32[i] != 0) 278 return (-1); 279 return (0); 280 default: 281 return (-1); 282 } 283 } 284 285 /* 286 * Test whether host portion of address 'a', as determined by 'masklen' 287 * is all zeros. 288 * Returns 0 on if host portion of address is all-zeros, 289 * -1 if not all zeros or on failure. 290 */ 291 static int 292 addr_host_is_all0s(const struct xaddr *a, u_int masklen) 293 { 294 struct xaddr tmp_addr, tmp_mask, tmp_result; 295 296 memcpy(&tmp_addr, a, sizeof(tmp_addr)); 297 if (addr_hostmask(a->af, masklen, &tmp_mask) == -1) 298 return (-1); 299 if (addr_and(&tmp_result, &tmp_addr, &tmp_mask) == -1) 300 return (-1); 301 return (addr_is_all0s(&tmp_result)); 302 } 303 304 /* 305 * Parse a CIDR address (x.x.x.x/y or xxxx:yyyy::/z). 306 * Return -1 on parse error, -2 on inconsistency or 0 on success. 307 */ 308 static int 309 addr_pton_cidr(const char *p, struct xaddr *n, u_int *l) 310 { 311 struct xaddr tmp; 312 long unsigned int masklen = 999; 313 char addrbuf[64], *mp, *cp; 314 315 /* Don't modify argument */ 316 if (p == NULL || strlcpy(addrbuf, p, sizeof(addrbuf)) >= sizeof(addrbuf)) 317 return -1; 318 319 if ((mp = strchr(addrbuf, '/')) != NULL) { 320 *mp = '\0'; 321 mp++; 322 masklen = strtoul(mp, &cp, 10); 323 if (*mp == '\0' || *cp != '\0' || masklen > 128) 324 return -1; 325 } 326 327 if (addr_pton(addrbuf, &tmp) == -1) 328 return -1; 329 330 if (mp == NULL) 331 masklen = addr_unicast_masklen(tmp.af); 332 if (masklen_valid(tmp.af, masklen) == -1) 333 return -2; 334 if (addr_host_is_all0s(&tmp, masklen) != 0) 335 return -2; 336 337 if (n != NULL) 338 memcpy(n, &tmp, sizeof(*n)); 339 if (l != NULL) 340 *l = masklen; 341 342 return 0; 343 } 344 345 static int 346 addr_netmatch(const struct xaddr *host, const struct xaddr *net, u_int masklen) 347 { 348 struct xaddr tmp_mask, tmp_result; 349 350 if (host->af != net->af) 351 return -1; 352 353 if (addr_netmask(host->af, masklen, &tmp_mask) == -1) 354 return -1; 355 if (addr_and(&tmp_result, host, &tmp_mask) == -1) 356 return -1; 357 return addr_cmp(&tmp_result, net); 358 } 359 360 /* 361 * Match "addr" against list pattern list "_list", which may contain a 362 * mix of CIDR addresses and old-school wildcards. 363 * 364 * If addr is NULL, then no matching is performed, but _list is parsed 365 * and checked for well-formedness. 366 * 367 * Returns 1 on match found (never returned when addr == NULL). 368 * Returns 0 on if no match found, or no errors found when addr == NULL. 369 * Returns -1 on negated match found (never returned when addr == NULL). 370 * Returns -2 on invalid list entry. 371 */ 372 int 373 addr_match_list(const char *addr, const char *_list) 374 { 375 char *list, *cp, *o; 376 struct xaddr try_addr, match_addr; 377 u_int masklen, neg; 378 int ret = 0, r; 379 380 if (addr != NULL && addr_pton(addr, &try_addr) != 0) { 381 debug2("%s: couldn't parse address %.100s", __func__, addr); 382 return 0; 383 } 384 if ((o = list = strdup(_list)) == NULL) 385 return -1; 386 while ((cp = strsep(&list, ",")) != NULL) { 387 neg = *cp == '!'; 388 if (neg) 389 cp++; 390 if (*cp == '\0') { 391 ret = -2; 392 break; 393 } 394 /* Prefer CIDR address matching */ 395 r = addr_pton_cidr(cp, &match_addr, &masklen); 396 if (r == -2) { 397 debug2("%s: inconsistent mask length for " 398 "match network \"%.100s\"", __func__, cp); 399 ret = -2; 400 break; 401 } else if (r == 0) { 402 if (addr != NULL && addr_netmatch(&try_addr, 403 &match_addr, masklen) == 0) { 404 foundit: 405 if (neg) { 406 ret = -1; 407 break; 408 } 409 ret = 1; 410 } 411 continue; 412 } else { 413 /* If CIDR parse failed, try wildcard string match */ 414 if (addr != NULL && match_pattern(addr, cp) == 1) 415 goto foundit; 416 } 417 } 418 free(o); 419 420 return ret; 421 } 422 423 /* 424 * Match "addr" against list CIDR list "_list". Lexical wildcards and 425 * negation are not supported. If "addr" == NULL, will verify structure 426 * of "_list". 427 * 428 * Returns 1 on match found (never returned when addr == NULL). 429 * Returns 0 on if no match found, or no errors found when addr == NULL. 430 * Returns -1 on error 431 */ 432 int 433 addr_match_cidr_list(const char *addr, const char *_list) 434 { 435 char *list, *cp, *o; 436 struct xaddr try_addr, match_addr; 437 u_int masklen; 438 int ret = 0, r; 439 440 if (addr != NULL && addr_pton(addr, &try_addr) != 0) { 441 debug2("%s: couldn't parse address %.100s", __func__, addr); 442 return 0; 443 } 444 if ((o = list = strdup(_list)) == NULL) 445 return -1; 446 while ((cp = strsep(&list, ",")) != NULL) { 447 if (*cp == '\0') { 448 error("%s: empty entry in list \"%.100s\"", 449 __func__, o); 450 ret = -1; 451 break; 452 } 453 454 /* 455 * NB. This function is called in pre-auth with untrusted data, 456 * so be extra paranoid about junk reaching getaddrino (via 457 * addr_pton_cidr). 458 */ 459 460 /* Stop junk from reaching getaddrinfo. +3 is for masklen */ 461 if (strlen(cp) > INET6_ADDRSTRLEN + 3) { 462 error("%s: list entry \"%.100s\" too long", 463 __func__, cp); 464 ret = -1; 465 break; 466 } 467 #define VALID_CIDR_CHARS "0123456789abcdefABCDEF.:/" 468 if (strspn(cp, VALID_CIDR_CHARS) != strlen(cp)) { 469 error("%s: list entry \"%.100s\" contains invalid " 470 "characters", __func__, cp); 471 ret = -1; 472 } 473 474 /* Prefer CIDR address matching */ 475 r = addr_pton_cidr(cp, &match_addr, &masklen); 476 if (r == -1) { 477 error("Invalid network entry \"%.100s\"", cp); 478 ret = -1; 479 break; 480 } else if (r == -2) { 481 error("Inconsistent mask length for " 482 "network \"%.100s\"", cp); 483 ret = -1; 484 break; 485 } else if (r == 0 && addr != NULL) { 486 if (addr_netmatch(&try_addr, &match_addr, 487 masklen) == 0) 488 ret = 1; 489 continue; 490 } 491 } 492 free(o); 493 494 return ret; 495 } 496