1 /* $OpenBSD: addrmatch.c,v 1.14 2018/07/31 03:07:24 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 "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 = NULL; 209 int ret = -1; 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 goto out; 216 if (ai == NULL || ai->ai_addr == NULL) 217 goto out; 218 if (n != NULL && addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen, n) == -1) 219 goto out; 220 /* success */ 221 ret = 0; 222 out: 223 if (ai != NULL) 224 freeaddrinfo(ai); 225 return ret; 226 } 227 228 /* 229 * Perform bitwise negation of address 230 * Returns 0 on success, -1 on failure. 231 */ 232 static int 233 addr_invert(struct xaddr *n) 234 { 235 int i; 236 237 if (n == NULL) 238 return (-1); 239 240 switch (n->af) { 241 case AF_INET: 242 n->v4.s_addr = ~n->v4.s_addr; 243 return (0); 244 case AF_INET6: 245 for (i = 0; i < 4; i++) 246 n->addr32[i] = ~n->addr32[i]; 247 return (0); 248 default: 249 return (-1); 250 } 251 } 252 253 /* 254 * Calculate a netmask of length 'l' for address family 'af' and 255 * store it in 'n'. 256 * Returns 0 on success, -1 on failure. 257 */ 258 static int 259 addr_hostmask(int af, u_int l, struct xaddr *n) 260 { 261 if (addr_netmask(af, l, n) == -1 || addr_invert(n) == -1) 262 return (-1); 263 return (0); 264 } 265 266 /* 267 * Test whether address 'a' is all zeros (i.e. 0.0.0.0 or ::) 268 * Returns 0 on if address is all-zeros, -1 if not all zeros or on failure. 269 */ 270 static int 271 addr_is_all0s(const struct xaddr *a) 272 { 273 int i; 274 275 switch (a->af) { 276 case AF_INET: 277 return (a->v4.s_addr == 0 ? 0 : -1); 278 case AF_INET6:; 279 for (i = 0; i < 4; i++) 280 if (a->addr32[i] != 0) 281 return (-1); 282 return (0); 283 default: 284 return (-1); 285 } 286 } 287 288 /* 289 * Test whether host portion of address 'a', as determined by 'masklen' 290 * is all zeros. 291 * Returns 0 on if host portion of address is all-zeros, 292 * -1 if not all zeros or on failure. 293 */ 294 static int 295 addr_host_is_all0s(const struct xaddr *a, u_int masklen) 296 { 297 struct xaddr tmp_addr, tmp_mask, tmp_result; 298 299 memcpy(&tmp_addr, a, sizeof(tmp_addr)); 300 if (addr_hostmask(a->af, masklen, &tmp_mask) == -1) 301 return (-1); 302 if (addr_and(&tmp_result, &tmp_addr, &tmp_mask) == -1) 303 return (-1); 304 return (addr_is_all0s(&tmp_result)); 305 } 306 307 /* 308 * Parse a CIDR address (x.x.x.x/y or xxxx:yyyy::/z). 309 * Return -1 on parse error, -2 on inconsistency or 0 on success. 310 */ 311 static int 312 addr_pton_cidr(const char *p, struct xaddr *n, u_int *l) 313 { 314 struct xaddr tmp; 315 long unsigned int masklen = 999; 316 char addrbuf[64], *mp, *cp; 317 318 /* Don't modify argument */ 319 if (p == NULL || strlcpy(addrbuf, p, sizeof(addrbuf)) >= sizeof(addrbuf)) 320 return -1; 321 322 if ((mp = strchr(addrbuf, '/')) != NULL) { 323 *mp = '\0'; 324 mp++; 325 masklen = strtoul(mp, &cp, 10); 326 if (*mp == '\0' || *cp != '\0' || masklen > 128) 327 return -1; 328 } 329 330 if (addr_pton(addrbuf, &tmp) == -1) 331 return -1; 332 333 if (mp == NULL) 334 masklen = addr_unicast_masklen(tmp.af); 335 if (masklen_valid(tmp.af, masklen) == -1) 336 return -2; 337 if (addr_host_is_all0s(&tmp, masklen) != 0) 338 return -2; 339 340 if (n != NULL) 341 memcpy(n, &tmp, sizeof(*n)); 342 if (l != NULL) 343 *l = masklen; 344 345 return 0; 346 } 347 348 static int 349 addr_netmatch(const struct xaddr *host, const struct xaddr *net, u_int masklen) 350 { 351 struct xaddr tmp_mask, tmp_result; 352 353 if (host->af != net->af) 354 return -1; 355 356 if (addr_netmask(host->af, masklen, &tmp_mask) == -1) 357 return -1; 358 if (addr_and(&tmp_result, host, &tmp_mask) == -1) 359 return -1; 360 return addr_cmp(&tmp_result, net); 361 } 362 363 /* 364 * Match "addr" against list pattern list "_list", which may contain a 365 * mix of CIDR addresses and old-school wildcards. 366 * 367 * If addr is NULL, then no matching is performed, but _list is parsed 368 * and checked for well-formedness. 369 * 370 * Returns 1 on match found (never returned when addr == NULL). 371 * Returns 0 on if no match found, or no errors found when addr == NULL. 372 * Returns -1 on negated match found (never returned when addr == NULL). 373 * Returns -2 on invalid list entry. 374 */ 375 int 376 addr_match_list(const char *addr, const char *_list) 377 { 378 char *list, *cp, *o; 379 struct xaddr try_addr, match_addr; 380 u_int masklen, neg; 381 int ret = 0, r; 382 383 if (addr != NULL && addr_pton(addr, &try_addr) != 0) { 384 debug2("%s: couldn't parse address %.100s", __func__, addr); 385 return 0; 386 } 387 if ((o = list = strdup(_list)) == NULL) 388 return -1; 389 while ((cp = strsep(&list, ",")) != NULL) { 390 neg = *cp == '!'; 391 if (neg) 392 cp++; 393 if (*cp == '\0') { 394 ret = -2; 395 break; 396 } 397 /* Prefer CIDR address matching */ 398 r = addr_pton_cidr(cp, &match_addr, &masklen); 399 if (r == -2) { 400 debug2("%s: inconsistent mask length for " 401 "match network \"%.100s\"", __func__, cp); 402 ret = -2; 403 break; 404 } else if (r == 0) { 405 if (addr != NULL && addr_netmatch(&try_addr, 406 &match_addr, masklen) == 0) { 407 foundit: 408 if (neg) { 409 ret = -1; 410 break; 411 } 412 ret = 1; 413 } 414 continue; 415 } else { 416 /* If CIDR parse failed, try wildcard string match */ 417 if (addr != NULL && match_pattern(addr, cp) == 1) 418 goto foundit; 419 } 420 } 421 free(o); 422 423 return ret; 424 } 425 426 /* 427 * Match "addr" against list CIDR list "_list". Lexical wildcards and 428 * negation are not supported. If "addr" == NULL, will verify structure 429 * of "_list". 430 * 431 * Returns 1 on match found (never returned when addr == NULL). 432 * Returns 0 on if no match found, or no errors found when addr == NULL. 433 * Returns -1 on error 434 */ 435 int 436 addr_match_cidr_list(const char *addr, const char *_list) 437 { 438 char *list, *cp, *o; 439 struct xaddr try_addr, match_addr; 440 u_int masklen; 441 int ret = 0, r; 442 443 if (addr != NULL && addr_pton(addr, &try_addr) != 0) { 444 debug2("%s: couldn't parse address %.100s", __func__, addr); 445 return 0; 446 } 447 if ((o = list = strdup(_list)) == NULL) 448 return -1; 449 while ((cp = strsep(&list, ",")) != NULL) { 450 if (*cp == '\0') { 451 error("%s: empty entry in list \"%.100s\"", 452 __func__, o); 453 ret = -1; 454 break; 455 } 456 457 /* 458 * NB. This function is called in pre-auth with untrusted data, 459 * so be extra paranoid about junk reaching getaddrino (via 460 * addr_pton_cidr). 461 */ 462 463 /* Stop junk from reaching getaddrinfo. +3 is for masklen */ 464 if (strlen(cp) > INET6_ADDRSTRLEN + 3) { 465 error("%s: list entry \"%.100s\" too long", 466 __func__, cp); 467 ret = -1; 468 break; 469 } 470 #define VALID_CIDR_CHARS "0123456789abcdefABCDEF.:/" 471 if (strspn(cp, VALID_CIDR_CHARS) != strlen(cp)) { 472 error("%s: list entry \"%.100s\" contains invalid " 473 "characters", __func__, cp); 474 ret = -1; 475 } 476 477 /* Prefer CIDR address matching */ 478 r = addr_pton_cidr(cp, &match_addr, &masklen); 479 if (r == -1) { 480 error("Invalid network entry \"%.100s\"", cp); 481 ret = -1; 482 break; 483 } else if (r == -2) { 484 error("Inconsistent mask length for " 485 "network \"%.100s\"", cp); 486 ret = -1; 487 break; 488 } else if (r == 0 && addr != NULL) { 489 if (addr_netmatch(&try_addr, &match_addr, 490 masklen) == 0) 491 ret = 1; 492 continue; 493 } 494 } 495 free(o); 496 497 return ret; 498 } 499