1 /* $OpenBSD: addrmatch.c,v 1.10 2015/07/08 19:04:21 markus 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 "includes.h" 20 21 #include <sys/types.h> 22 #include <sys/socket.h> 23 #include <netinet/in.h> 24 #include <arpa/inet.h> 25 26 #include <netdb.h> 27 #include <string.h> 28 #include <stdlib.h> 29 #include <stdio.h> 30 #include <stdarg.h> 31 32 #include "match.h" 33 #include "log.h" 34 35 struct xaddr { 36 sa_family_t af; 37 union { 38 struct in_addr v4; 39 struct in6_addr v6; 40 u_int8_t addr8[16]; 41 u_int32_t addr32[4]; 42 } xa; /* 128-bit address */ 43 u_int32_t scope_id; /* iface scope id for v6 */ 44 #define v4 xa.v4 45 #define v6 xa.v6 46 #define addr8 xa.addr8 47 #define addr32 xa.addr32 48 }; 49 50 static int 51 addr_unicast_masklen(int af) 52 { 53 switch (af) { 54 case AF_INET: 55 return 32; 56 case AF_INET6: 57 return 128; 58 default: 59 return -1; 60 } 61 } 62 63 static inline int 64 masklen_valid(int af, u_int masklen) 65 { 66 switch (af) { 67 case AF_INET: 68 return masklen <= 32 ? 0 : -1; 69 case AF_INET6: 70 return masklen <= 128 ? 0 : -1; 71 default: 72 return -1; 73 } 74 } 75 76 /* 77 * Convert struct sockaddr to struct xaddr 78 * Returns 0 on success, -1 on failure. 79 */ 80 static int 81 addr_sa_to_xaddr(struct sockaddr *sa, socklen_t slen, struct xaddr *xa) 82 { 83 struct sockaddr_in *in4 = (struct sockaddr_in *)sa; 84 struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)sa; 85 86 memset(xa, '\0', sizeof(*xa)); 87 88 switch (sa->sa_family) { 89 case AF_INET: 90 if (slen < (socklen_t)sizeof(*in4)) 91 return -1; 92 xa->af = AF_INET; 93 memcpy(&xa->v4, &in4->sin_addr, sizeof(xa->v4)); 94 break; 95 case AF_INET6: 96 if (slen < (socklen_t)sizeof(*in6)) 97 return -1; 98 xa->af = AF_INET6; 99 memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6)); 100 #ifdef HAVE_STRUCT_SOCKADDR_IN6_SIN6_SCOPE_ID 101 xa->scope_id = in6->sin6_scope_id; 102 #endif 103 break; 104 default: 105 return -1; 106 } 107 108 return 0; 109 } 110 111 /* 112 * Calculate a netmask of length 'l' for address family 'af' and 113 * store it in 'n'. 114 * Returns 0 on success, -1 on failure. 115 */ 116 static int 117 addr_netmask(int af, u_int l, struct xaddr *n) 118 { 119 int i; 120 121 if (masklen_valid(af, l) != 0 || n == NULL) 122 return -1; 123 124 memset(n, '\0', sizeof(*n)); 125 switch (af) { 126 case AF_INET: 127 n->af = AF_INET; 128 if (l == 0) 129 return 0; 130 n->v4.s_addr = htonl((0xffffffff << (32 - l)) & 0xffffffff); 131 return 0; 132 case AF_INET6: 133 n->af = AF_INET6; 134 for (i = 0; i < 4 && l >= 32; i++, l -= 32) 135 n->addr32[i] = 0xffffffffU; 136 if (i < 4 && l != 0) 137 n->addr32[i] = htonl((0xffffffff << (32 - l)) & 138 0xffffffff); 139 return 0; 140 default: 141 return -1; 142 } 143 } 144 145 /* 146 * Perform logical AND of addresses 'a' and 'b', storing result in 'dst'. 147 * Returns 0 on success, -1 on failure. 148 */ 149 static int 150 addr_and(struct xaddr *dst, const struct xaddr *a, const struct xaddr *b) 151 { 152 int i; 153 154 if (dst == NULL || a == NULL || b == NULL || a->af != b->af) 155 return -1; 156 157 memcpy(dst, a, sizeof(*dst)); 158 switch (a->af) { 159 case AF_INET: 160 dst->v4.s_addr &= b->v4.s_addr; 161 return 0; 162 case AF_INET6: 163 dst->scope_id = a->scope_id; 164 for (i = 0; i < 4; i++) 165 dst->addr32[i] &= b->addr32[i]; 166 return 0; 167 default: 168 return -1; 169 } 170 } 171 172 /* 173 * Compare addresses 'a' and 'b' 174 * Return 0 if addresses are identical, -1 if (a < b) or 1 if (a > b) 175 */ 176 static int 177 addr_cmp(const struct xaddr *a, const struct xaddr *b) 178 { 179 int i; 180 181 if (a->af != b->af) 182 return a->af == AF_INET6 ? 1 : -1; 183 184 switch (a->af) { 185 case AF_INET: 186 if (a->v4.s_addr == b->v4.s_addr) 187 return 0; 188 return ntohl(a->v4.s_addr) > ntohl(b->v4.s_addr) ? 1 : -1; 189 case AF_INET6: 190 for (i = 0; i < 16; i++) 191 if (a->addr8[i] - b->addr8[i] != 0) 192 return a->addr8[i] > b->addr8[i] ? 1 : -1; 193 if (a->scope_id == b->scope_id) 194 return 0; 195 return a->scope_id > b->scope_id ? 1 : -1; 196 default: 197 return -1; 198 } 199 } 200 201 /* 202 * Parse string address 'p' into 'n' 203 * Returns 0 on success, -1 on failure. 204 */ 205 static int 206 addr_pton(const char *p, struct xaddr *n) 207 { 208 struct addrinfo hints, *ai; 209 210 memset(&hints, '\0', sizeof(hints)); 211 hints.ai_flags = AI_NUMERICHOST; 212 213 if (p == NULL || getaddrinfo(p, NULL, &hints, &ai) != 0) 214 return -1; 215 216 if (ai == NULL || ai->ai_addr == NULL) 217 return -1; 218 219 if (n != NULL && 220 addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen, n) == -1) { 221 freeaddrinfo(ai); 222 return -1; 223 } 224 225 freeaddrinfo(ai); 226 return 0; 227 } 228 229 /* 230 * Perform bitwise negation of address 231 * Returns 0 on success, -1 on failure. 232 */ 233 static int 234 addr_invert(struct xaddr *n) 235 { 236 int i; 237 238 if (n == NULL) 239 return (-1); 240 241 switch (n->af) { 242 case AF_INET: 243 n->v4.s_addr = ~n->v4.s_addr; 244 return (0); 245 case AF_INET6: 246 for (i = 0; i < 4; i++) 247 n->addr32[i] = ~n->addr32[i]; 248 return (0); 249 default: 250 return (-1); 251 } 252 } 253 254 /* 255 * Calculate a netmask of length 'l' for address family 'af' and 256 * store it in 'n'. 257 * Returns 0 on success, -1 on failure. 258 */ 259 static int 260 addr_hostmask(int af, u_int l, struct xaddr *n) 261 { 262 if (addr_netmask(af, l, n) == -1 || addr_invert(n) == -1) 263 return (-1); 264 return (0); 265 } 266 267 /* 268 * Test whether address 'a' is all zeros (i.e. 0.0.0.0 or ::) 269 * Returns 0 on if address is all-zeros, -1 if not all zeros or on failure. 270 */ 271 static int 272 addr_is_all0s(const struct xaddr *a) 273 { 274 int i; 275 276 switch (a->af) { 277 case AF_INET: 278 return (a->v4.s_addr == 0 ? 0 : -1); 279 case AF_INET6:; 280 for (i = 0; i < 4; i++) 281 if (a->addr32[i] != 0) 282 return (-1); 283 return (0); 284 default: 285 return (-1); 286 } 287 } 288 289 /* 290 * Test whether host portion of address 'a', as determined by 'masklen' 291 * is all zeros. 292 * Returns 0 on if host portion of address is all-zeros, 293 * -1 if not all zeros or on failure. 294 */ 295 static int 296 addr_host_is_all0s(const struct xaddr *a, u_int masklen) 297 { 298 struct xaddr tmp_addr, tmp_mask, tmp_result; 299 300 memcpy(&tmp_addr, a, sizeof(tmp_addr)); 301 if (addr_hostmask(a->af, masklen, &tmp_mask) == -1) 302 return (-1); 303 if (addr_and(&tmp_result, &tmp_addr, &tmp_mask) == -1) 304 return (-1); 305 return (addr_is_all0s(&tmp_result)); 306 } 307 308 /* 309 * Parse a CIDR address (x.x.x.x/y or xxxx:yyyy::/z). 310 * Return -1 on parse error, -2 on inconsistency or 0 on success. 311 */ 312 static int 313 addr_pton_cidr(const char *p, struct xaddr *n, u_int *l) 314 { 315 struct xaddr tmp; 316 long unsigned int masklen = 999; 317 char addrbuf[64], *mp, *cp; 318 319 /* Don't modify argument */ 320 if (p == NULL || strlcpy(addrbuf, p, sizeof(addrbuf)) >= sizeof(addrbuf)) 321 return -1; 322 323 if ((mp = strchr(addrbuf, '/')) != NULL) { 324 *mp = '\0'; 325 mp++; 326 masklen = strtoul(mp, &cp, 10); 327 if (*mp == '\0' || *cp != '\0' || masklen > 128) 328 return -1; 329 } 330 331 if (addr_pton(addrbuf, &tmp) == -1) 332 return -1; 333 334 if (mp == NULL) 335 masklen = addr_unicast_masklen(tmp.af); 336 if (masklen_valid(tmp.af, masklen) == -1) 337 return -2; 338 if (addr_host_is_all0s(&tmp, masklen) != 0) 339 return -2; 340 341 if (n != NULL) 342 memcpy(n, &tmp, sizeof(*n)); 343 if (l != NULL) 344 *l = masklen; 345 346 return 0; 347 } 348 349 static int 350 addr_netmatch(const struct xaddr *host, const struct xaddr *net, u_int masklen) 351 { 352 struct xaddr tmp_mask, tmp_result; 353 354 if (host->af != net->af) 355 return -1; 356 357 if (addr_netmask(host->af, masklen, &tmp_mask) == -1) 358 return -1; 359 if (addr_and(&tmp_result, host, &tmp_mask) == -1) 360 return -1; 361 return addr_cmp(&tmp_result, net); 362 } 363 364 /* 365 * Match "addr" against list pattern list "_list", which may contain a 366 * mix of CIDR addresses and old-school wildcards. 367 * 368 * If addr is NULL, then no matching is performed, but _list is parsed 369 * and checked for well-formedness. 370 * 371 * Returns 1 on match found (never returned when addr == NULL). 372 * Returns 0 on if no match found, or no errors found when addr == NULL. 373 * Returns -1 on negated match found (never returned when addr == NULL). 374 * Returns -2 on invalid list entry. 375 */ 376 int 377 addr_match_list(const char *addr, const char *_list) 378 { 379 char *list, *cp, *o; 380 struct xaddr try_addr, match_addr; 381 u_int masklen, neg; 382 int ret = 0, r; 383 384 if (addr != NULL && addr_pton(addr, &try_addr) != 0) { 385 debug2("%s: couldn't parse address %.100s", __func__, addr); 386 return 0; 387 } 388 if ((o = list = strdup(_list)) == NULL) 389 return -1; 390 while ((cp = strsep(&list, ",")) != NULL) { 391 neg = *cp == '!'; 392 if (neg) 393 cp++; 394 if (*cp == '\0') { 395 ret = -2; 396 break; 397 } 398 /* Prefer CIDR address matching */ 399 r = addr_pton_cidr(cp, &match_addr, &masklen); 400 if (r == -2) { 401 error("Inconsistent mask length for " 402 "network \"%.100s\"", cp); 403 ret = -2; 404 break; 405 } else if (r == 0) { 406 if (addr != NULL && addr_netmatch(&try_addr, 407 &match_addr, masklen) == 0) { 408 foundit: 409 if (neg) { 410 ret = -1; 411 break; 412 } 413 ret = 1; 414 } 415 continue; 416 } else { 417 /* If CIDR parse failed, try wildcard string match */ 418 if (addr != NULL && match_pattern(addr, cp) == 1) 419 goto foundit; 420 } 421 } 422 free(o); 423 424 return ret; 425 } 426 427 /* 428 * Match "addr" against list CIDR list "_list". Lexical wildcards and 429 * negation are not supported. If "addr" == NULL, will verify structure 430 * of "_list". 431 * 432 * Returns 1 on match found (never returned when addr == NULL). 433 * Returns 0 on if no match found, or no errors found when addr == NULL. 434 * Returns -1 on error 435 */ 436 int 437 addr_match_cidr_list(const char *addr, const char *_list) 438 { 439 char *list, *cp, *o; 440 struct xaddr try_addr, match_addr; 441 u_int masklen; 442 int ret = 0, r; 443 444 if (addr != NULL && addr_pton(addr, &try_addr) != 0) { 445 debug2("%s: couldn't parse address %.100s", __func__, addr); 446 return 0; 447 } 448 if ((o = list = strdup(_list)) == NULL) 449 return -1; 450 while ((cp = strsep(&list, ",")) != NULL) { 451 if (*cp == '\0') { 452 error("%s: empty entry in list \"%.100s\"", 453 __func__, o); 454 ret = -1; 455 break; 456 } 457 458 /* 459 * NB. This function is called in pre-auth with untrusted data, 460 * so be extra paranoid about junk reaching getaddrino (via 461 * addr_pton_cidr). 462 */ 463 464 /* Stop junk from reaching getaddrinfo. +3 is for masklen */ 465 if (strlen(cp) > INET6_ADDRSTRLEN + 3) { 466 error("%s: list entry \"%.100s\" too long", 467 __func__, cp); 468 ret = -1; 469 break; 470 } 471 #define VALID_CIDR_CHARS "0123456789abcdefABCDEF.:/" 472 if (strspn(cp, VALID_CIDR_CHARS) != strlen(cp)) { 473 error("%s: list entry \"%.100s\" contains invalid " 474 "characters", __func__, cp); 475 ret = -1; 476 } 477 478 /* Prefer CIDR address matching */ 479 r = addr_pton_cidr(cp, &match_addr, &masklen); 480 if (r == -1) { 481 error("Invalid network entry \"%.100s\"", cp); 482 ret = -1; 483 break; 484 } else if (r == -2) { 485 error("Inconsistent mask length for " 486 "network \"%.100s\"", cp); 487 ret = -1; 488 break; 489 } else if (r == 0 && addr != NULL) { 490 if (addr_netmatch(&try_addr, &match_addr, 491 masklen) == 0) 492 ret = 1; 493 continue; 494 } 495 } 496 free(o); 497 498 return ret; 499 } 500