1 /* $OpenBSD: addrmatch.c,v 1.5 2010/02/26 20:29:54 djm Exp $ */ 2 3 /* 4 * Copyright (c) 2004-2008 Damien Miller <djm (at) 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 #include "xmalloc.h" 35 36 struct xaddr { 37 sa_family_t af; 38 union { 39 struct in_addr v4; 40 struct in6_addr v6; 41 u_int8_t addr8[16]; 42 u_int32_t addr32[4]; 43 } xa; /* 128-bit address */ 44 u_int32_t scope_id; /* iface scope id for v6 */ 45 #define v4 xa.v4 46 #define v6 xa.v6 47 #define addr8 xa.addr8 48 #define addr32 xa.addr32 49 }; 50 51 static int 52 addr_unicast_masklen(int af) 53 { 54 switch (af) { 55 case AF_INET: 56 return 32; 57 case AF_INET6: 58 return 128; 59 default: 60 return -1; 61 } 62 } 63 64 static inline int 65 masklen_valid(int af, u_int masklen) 66 { 67 switch (af) { 68 case AF_INET: 69 return masklen <= 32 ? 0 : -1; 70 case AF_INET6: 71 return masklen <= 128 ? 0 : -1; 72 default: 73 return -1; 74 } 75 } 76 77 /* 78 * Convert struct sockaddr to struct xaddr 79 * Returns 0 on success, -1 on failure. 80 */ 81 static int 82 addr_sa_to_xaddr(struct sockaddr *sa, socklen_t slen, struct xaddr *xa) 83 { 84 struct sockaddr_in *in4 = (struct sockaddr_in *)sa; 85 struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)sa; 86 87 memset(xa, '\0', sizeof(*xa)); 88 89 switch (sa->sa_family) { 90 case AF_INET: 91 if (slen < sizeof(*in4)) 92 return -1; 93 xa->af = AF_INET; 94 memcpy(&xa->v4, &in4->sin_addr, sizeof(xa->v4)); 95 break; 96 case AF_INET6: 97 if (slen < sizeof(*in6)) 98 return -1; 99 xa->af = AF_INET6; 100 memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6)); 101 #ifdef HAVE_STRUCT_SOCKADDR_IN6_SIN6_SCOPE_ID 102 xa->scope_id = in6->sin6_scope_id; 103 #endif 104 break; 105 default: 106 return -1; 107 } 108 109 return 0; 110 } 111 112 /* 113 * Calculate a netmask of length 'l' for address family 'af' and 114 * store it in 'n'. 115 * Returns 0 on success, -1 on failure. 116 */ 117 static int 118 addr_netmask(int af, u_int l, struct xaddr *n) 119 { 120 int i; 121 122 if (masklen_valid(af, l) != 0 || n == NULL) 123 return -1; 124 125 memset(n, '\0', sizeof(*n)); 126 switch (af) { 127 case AF_INET: 128 n->af = AF_INET; 129 if (l == 0) 130 return 0; 131 n->v4.s_addr = htonl((0xffffffff << (32 - l)) & 0xffffffff); 132 return 0; 133 case AF_INET6: 134 n->af = AF_INET6; 135 for (i = 0; i < 4 && l >= 32; i++, l -= 32) 136 n->addr32[i] = 0xffffffffU; 137 if (i < 4 && l != 0) 138 n->addr32[i] = htonl((0xffffffff << (32 - l)) & 139 0xffffffff); 140 return 0; 141 default: 142 return -1; 143 } 144 } 145 146 /* 147 * Perform logical AND of addresses 'a' and 'b', storing result in 'dst'. 148 * Returns 0 on success, -1 on failure. 149 */ 150 static int 151 addr_and(struct xaddr *dst, const struct xaddr *a, const struct xaddr *b) 152 { 153 int i; 154 155 if (dst == NULL || a == NULL || b == NULL || a->af != b->af) 156 return -1; 157 158 memcpy(dst, a, sizeof(*dst)); 159 switch (a->af) { 160 case AF_INET: 161 dst->v4.s_addr &= b->v4.s_addr; 162 return 0; 163 case AF_INET6: 164 dst->scope_id = a->scope_id; 165 for (i = 0; i < 4; i++) 166 dst->addr32[i] &= b->addr32[i]; 167 return 0; 168 default: 169 return -1; 170 } 171 } 172 173 /* 174 * Compare addresses 'a' and 'b' 175 * Return 0 if addresses are identical, -1 if (a < b) or 1 if (a > b) 176 */ 177 static int 178 addr_cmp(const struct xaddr *a, const struct xaddr *b) 179 { 180 int i; 181 182 if (a->af != b->af) 183 return a->af == AF_INET6 ? 1 : -1; 184 185 switch (a->af) { 186 case AF_INET: 187 if (a->v4.s_addr == b->v4.s_addr) 188 return 0; 189 return ntohl(a->v4.s_addr) > ntohl(b->v4.s_addr) ? 1 : -1; 190 case AF_INET6: 191 for (i = 0; i < 16; i++) 192 if (a->addr8[i] - b->addr8[i] != 0) 193 return a->addr8[i] > b->addr8[i] ? 1 : -1; 194 if (a->scope_id == b->scope_id) 195 return 0; 196 return a->scope_id > b->scope_id ? 1 : -1; 197 default: 198 return -1; 199 } 200 } 201 202 /* 203 * Parse string address 'p' into 'n' 204 * Returns 0 on success, -1 on failure. 205 */ 206 static int 207 addr_pton(const char *p, struct xaddr *n) 208 { 209 struct addrinfo hints, *ai; 210 211 memset(&hints, '\0', sizeof(hints)); 212 hints.ai_flags = AI_NUMERICHOST; 213 214 if (p == NULL || getaddrinfo(p, NULL, &hints, &ai) != 0) 215 return -1; 216 217 if (ai == NULL || ai->ai_addr == NULL) 218 return -1; 219 220 if (n != NULL && 221 addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen, n) == -1) { 222 freeaddrinfo(ai); 223 return -1; 224 } 225 226 freeaddrinfo(ai); 227 return 0; 228 } 229 230 /* 231 * Perform bitwise negation of address 232 * Returns 0 on success, -1 on failure. 233 */ 234 static int 235 addr_invert(struct xaddr *n) 236 { 237 int i; 238 239 if (n == NULL) 240 return (-1); 241 242 switch (n->af) { 243 case AF_INET: 244 n->v4.s_addr = ~n->v4.s_addr; 245 return (0); 246 case AF_INET6: 247 for (i = 0; i < 4; i++) 248 n->addr32[i] = ~n->addr32[i]; 249 return (0); 250 default: 251 return (-1); 252 } 253 } 254 255 /* 256 * Calculate a netmask of length 'l' for address family 'af' and 257 * store it in 'n'. 258 * Returns 0 on success, -1 on failure. 259 */ 260 static int 261 addr_hostmask(int af, u_int l, struct xaddr *n) 262 { 263 if (addr_netmask(af, l, n) == -1 || addr_invert(n) == -1) 264 return (-1); 265 return (0); 266 } 267 268 /* 269 * Test whether address 'a' is all zeros (i.e. 0.0.0.0 or ::) 270 * Returns 0 on if address is all-zeros, -1 if not all zeros or on failure. 271 */ 272 static int 273 addr_is_all0s(const struct xaddr *a) 274 { 275 int i; 276 277 switch (a->af) { 278 case AF_INET: 279 return (a->v4.s_addr == 0 ? 0 : -1); 280 case AF_INET6:; 281 for (i = 0; i < 4; i++) 282 if (a->addr32[i] != 0) 283 return (-1); 284 return (0); 285 default: 286 return (-1); 287 } 288 } 289 290 /* 291 * Test whether host portion of address 'a', as determined by 'masklen' 292 * is all zeros. 293 * Returns 0 on if host portion of address is all-zeros, 294 * -1 if not all zeros or on failure. 295 */ 296 static int 297 addr_host_is_all0s(const struct xaddr *a, u_int masklen) 298 { 299 struct xaddr tmp_addr, tmp_mask, tmp_result; 300 301 memcpy(&tmp_addr, a, sizeof(tmp_addr)); 302 if (addr_hostmask(a->af, masklen, &tmp_mask) == -1) 303 return (-1); 304 if (addr_and(&tmp_result, &tmp_addr, &tmp_mask) == -1) 305 return (-1); 306 return (addr_is_all0s(&tmp_result)); 307 } 308 309 /* 310 * Parse a CIDR address (x.x.x.x/y or xxxx:yyyy::/z). 311 * Return -1 on parse error, -2 on inconsistency or 0 on success. 312 */ 313 static int 314 addr_pton_cidr(const char *p, struct xaddr *n, u_int *l) 315 { 316 struct xaddr tmp; 317 long unsigned int masklen = 999; 318 char addrbuf[64], *mp, *cp; 319 320 /* Don't modify argument */ 321 if (p == NULL || strlcpy(addrbuf, p, sizeof(addrbuf)) > sizeof(addrbuf)) 322 return -1; 323 324 if ((mp = strchr(addrbuf, '/')) != NULL) { 325 *mp = '\0'; 326 mp++; 327 masklen = strtoul(mp, &cp, 10); 328 if (*mp == '\0' || *cp != '\0' || masklen > 128) 329 return -1; 330 } 331 332 if (addr_pton(addrbuf, &tmp) == -1) 333 return -1; 334 335 if (mp == NULL) 336 masklen = addr_unicast_masklen(tmp.af); 337 if (masklen_valid(tmp.af, masklen) == -1) 338 return -2; 339 if (addr_host_is_all0s(&tmp, masklen) != 0) 340 return -2; 341 342 if (n != NULL) 343 memcpy(n, &tmp, sizeof(*n)); 344 if (l != NULL) 345 *l = masklen; 346 347 return 0; 348 } 349 350 static int 351 addr_netmatch(const struct xaddr *host, const struct xaddr *net, u_int masklen) 352 { 353 struct xaddr tmp_mask, tmp_result; 354 355 if (host->af != net->af) 356 return -1; 357 358 if (addr_netmask(host->af, masklen, &tmp_mask) == -1) 359 return -1; 360 if (addr_and(&tmp_result, host, &tmp_mask) == -1) 361 return -1; 362 return addr_cmp(&tmp_result, net); 363 } 364 365 /* 366 * Match "addr" against list pattern list "_list", which may contain a 367 * mix of CIDR addresses and old-school wildcards. 368 * 369 * If addr is NULL, then no matching is performed, but _list is parsed 370 * and checked for well-formedness. 371 * 372 * Returns 1 on match found (never returned when addr == NULL). 373 * Returns 0 on if no match found, or no errors found when addr == NULL. 374 * Returns -1 on negated match found (never returned when addr == NULL). 375 * Returns -2 on invalid list entry. 376 */ 377 int 378 addr_match_list(const char *addr, const char *_list) 379 { 380 char *list, *cp, *o; 381 struct xaddr try_addr, match_addr; 382 u_int masklen, neg; 383 int ret = 0, r; 384 385 if (addr != NULL && addr_pton(addr, &try_addr) != 0) { 386 debug2("%s: couldn't parse address %.100s", __func__, addr); 387 return 0; 388 } 389 if ((o = list = strdup(_list)) == NULL) 390 return -1; 391 while ((cp = strsep(&list, ",")) != NULL) { 392 neg = *cp == '!'; 393 if (neg) 394 cp++; 395 if (*cp == '\0') { 396 ret = -2; 397 break; 398 } 399 /* Prefer CIDR address matching */ 400 r = addr_pton_cidr(cp, &match_addr, &masklen); 401 if (r == -2) { 402 error("Inconsistent mask length for " 403 "network \"%.100s\"", cp); 404 ret = -2; 405 break; 406 } else if (r == 0) { 407 if (addr != NULL && addr_netmatch(&try_addr, 408 &match_addr, masklen) == 0) { 409 foundit: 410 if (neg) { 411 ret = -1; 412 break; 413 } 414 ret = 1; 415 } 416 continue; 417 } else { 418 /* If CIDR parse failed, try wildcard string match */ 419 if (addr != NULL && match_pattern(addr, cp) == 1) 420 goto foundit; 421 } 422 } 423 xfree(o); 424 425 return ret; 426 } 427 428 /* 429 * Match "addr" against list CIDR list "_list". Lexical wildcards and 430 * negation are not supported. If "addr" == NULL, will verify structure 431 * of "_list". 432 * 433 * Returns 1 on match found (never returned when addr == NULL). 434 * Returns 0 on if no match found, or no errors found when addr == NULL. 435 * Returns -1 on error 436 */ 437 int 438 addr_match_cidr_list(const char *addr, const char *_list) 439 { 440 char *list, *cp, *o; 441 struct xaddr try_addr, match_addr; 442 u_int masklen; 443 int ret = 0, r; 444 445 if (addr != NULL && addr_pton(addr, &try_addr) != 0) { 446 debug2("%s: couldn't parse address %.100s", __func__, addr); 447 return 0; 448 } 449 if ((o = list = strdup(_list)) == NULL) 450 return -1; 451 while ((cp = strsep(&list, ",")) != NULL) { 452 if (*cp == '\0') { 453 error("%s: empty entry in list \"%.100s\"", 454 __func__, o); 455 ret = -1; 456 break; 457 } 458 459 /* 460 * NB. This function is called in pre-auth with untrusted data, 461 * so be extra paranoid about junk reaching getaddrino (via 462 * addr_pton_cidr). 463 */ 464 465 /* Stop junk from reaching getaddrinfo. +3 is for masklen */ 466 if (strlen(cp) > INET6_ADDRSTRLEN + 3) { 467 error("%s: list entry \"%.100s\" too long", 468 __func__, cp); 469 ret = -1; 470 break; 471 } 472 #define VALID_CIDR_CHARS "0123456789abcdefABCDEF.:/" 473 if (strspn(cp, VALID_CIDR_CHARS) != strlen(cp)) { 474 error("%s: list entry \"%.100s\" contains invalid " 475 "characters", __func__, cp); 476 ret = -1; 477 } 478 479 /* Prefer CIDR address matching */ 480 r = addr_pton_cidr(cp, &match_addr, &masklen); 481 if (r == -1) { 482 error("Invalid network entry \"%.100s\"", cp); 483 ret = -1; 484 break; 485 } else if (r == -2) { 486 error("Inconsistent mask length for " 487 "network \"%.100s\"", cp); 488 ret = -1; 489 break; 490 } else if (r == 0 && addr != NULL) { 491 if (addr_netmatch(&try_addr, &match_addr, 492 masklen) == 0) 493 ret = 1; 494 continue; 495 } 496 } 497 xfree(o); 498 499 return ret; 500 } 501
