1 /* $NetBSD: addrmatch.c,v 1.11 2017/04/18 18:41:46 christos Exp $ */ 2 /* $OpenBSD: addrmatch.c,v 1.13 2016/09/21 16:55:42 djm Exp $ */ 3 4 /* 5 * Copyright (c) 2004-2008 Damien Miller <djm@mindrot.org> 6 * 7 * Permission to use, copy, modify, and distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 18 */ 19 20 #include "includes.h" 21 __RCSID("$NetBSD: addrmatch.c,v 1.11 2017/04/18 18:41:46 christos Exp $"); 22 #include <sys/types.h> 23 #include <sys/socket.h> 24 #include <netinet/in.h> 25 #include <arpa/inet.h> 26 27 #include <netdb.h> 28 #include <string.h> 29 #include <stdlib.h> 30 #include <stdio.h> 31 #include <stdarg.h> 32 33 #include "match.h" 34 #include "log.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 *)(void *)sa; 85 struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)(void *)sa; 86 87 memset(xa, '\0', sizeof(*xa)); 88 89 switch (sa->sa_family) { 90 case AF_INET: 91 if (slen < (socklen_t)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 < (socklen_t)sizeof(*in6)) 98 return -1; 99 xa->af = AF_INET6; 100 memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6)); 101 xa->scope_id = in6->sin6_scope_id; 102 break; 103 default: 104 return -1; 105 } 106 107 return 0; 108 } 109 110 /* 111 * Calculate a netmask of length 'l' for address family 'af' and 112 * store it in 'n'. 113 * Returns 0 on success, -1 on failure. 114 */ 115 static int 116 addr_netmask(int af, u_int l, struct xaddr *n) 117 { 118 int i; 119 120 if (masklen_valid(af, l) != 0 || n == NULL) 121 return -1; 122 123 memset(n, '\0', sizeof(*n)); 124 switch (af) { 125 case AF_INET: 126 n->af = AF_INET; 127 if (l == 0) 128 return 0; 129 n->v4.s_addr = htonl((0xffffffff << (32 - l)) & 0xffffffff); 130 return 0; 131 case AF_INET6: 132 n->af = AF_INET6; 133 for (i = 0; i < 4 && l >= 32; i++, l -= 32) 134 n->addr32[i] = 0xffffffffU; 135 if (i < 4 && l != 0) 136 n->addr32[i] = htonl((0xffffffff << (32 - l)) & 137 0xffffffff); 138 return 0; 139 default: 140 return -1; 141 } 142 } 143 144 /* 145 * Perform logical AND of addresses 'a' and 'b', storing result in 'dst'. 146 * Returns 0 on success, -1 on failure. 147 */ 148 static int 149 addr_and(struct xaddr *dst, const struct xaddr *a, const struct xaddr *b) 150 { 151 int i; 152 153 if (dst == NULL || a == NULL || b == NULL || a->af != b->af) 154 return -1; 155 156 memcpy(dst, a, sizeof(*dst)); 157 switch (a->af) { 158 case AF_INET: 159 dst->v4.s_addr &= b->v4.s_addr; 160 return 0; 161 case AF_INET6: 162 dst->scope_id = a->scope_id; 163 for (i = 0; i < 4; i++) 164 dst->addr32[i] &= b->addr32[i]; 165 return 0; 166 default: 167 return -1; 168 } 169 } 170 171 /* 172 * Compare addresses 'a' and 'b' 173 * Return 0 if addresses are identical, -1 if (a < b) or 1 if (a > b) 174 */ 175 static int 176 addr_cmp(const struct xaddr *a, const struct xaddr *b) 177 { 178 int i; 179 180 if (a->af != b->af) 181 return a->af == AF_INET6 ? 1 : -1; 182 183 switch (a->af) { 184 case AF_INET: 185 if (a->v4.s_addr == b->v4.s_addr) 186 return 0; 187 return ntohl(a->v4.s_addr) > ntohl(b->v4.s_addr) ? 1 : -1; 188 case AF_INET6: 189 for (i = 0; i < 16; i++) 190 if (a->addr8[i] - b->addr8[i] != 0) 191 return a->addr8[i] > b->addr8[i] ? 1 : -1; 192 if (a->scope_id == b->scope_id) 193 return 0; 194 return a->scope_id > b->scope_id ? 1 : -1; 195 default: 196 return -1; 197 } 198 } 199 200 /* 201 * Parse string address 'p' into 'n' 202 * Returns 0 on success, -1 on failure. 203 */ 204 static int 205 addr_pton(const char *p, struct xaddr *n) 206 { 207 struct addrinfo hints, *ai; 208 209 memset(&hints, '\0', sizeof(hints)); 210 hints.ai_flags = AI_NUMERICHOST; 211 212 if (p == NULL || getaddrinfo(p, NULL, &hints, &ai) != 0) 213 return -1; 214 215 if (ai == NULL || ai->ai_addr == NULL) 216 return -1; 217 218 if (n != NULL && 219 addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen, n) == -1) { 220 freeaddrinfo(ai); 221 return -1; 222 } 223 224 freeaddrinfo(ai); 225 return 0; 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 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