1 /* $NetBSD: addrmatch.c,v 1.13 2019/01/27 02:08:33 pgoyette Exp $ */ 2 /* $OpenBSD: addrmatch.c,v 1.14 2018/07/31 03:07:24 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 1.13 2019/01/27 02:08:33 pgoyette 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 = NULL; 208 int ret = -1; 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 goto out; 215 if (ai == NULL || ai->ai_addr == NULL) 216 goto out; 217 if (n != NULL && addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen, n) == -1) 218 goto out; 219 /* success */ 220 ret = 0; 221 out: 222 if (ai != NULL) 223 freeaddrinfo(ai); 224 return ret; 225 } 226 227 /* 228 * Perform bitwise negation of address 229 * Returns 0 on success, -1 on failure. 230 */ 231 static int 232 addr_invert(struct xaddr *n) 233 { 234 int i; 235 236 if (n == NULL) 237 return (-1); 238 239 switch (n->af) { 240 case AF_INET: 241 n->v4.s_addr = ~n->v4.s_addr; 242 return (0); 243 case AF_INET6: 244 for (i = 0; i < 4; i++) 245 n->addr32[i] = ~n->addr32[i]; 246 return (0); 247 default: 248 return (-1); 249 } 250 } 251 252 /* 253 * Calculate a netmask of length 'l' for address family 'af' and 254 * store it in 'n'. 255 * Returns 0 on success, -1 on failure. 256 */ 257 static int 258 addr_hostmask(int af, u_int l, struct xaddr *n) 259 { 260 if (addr_netmask(af, l, n) == -1 || addr_invert(n) == -1) 261 return (-1); 262 return (0); 263 } 264 265 /* 266 * Test whether address 'a' is all zeros (i.e. 0.0.0.0 or ::) 267 * Returns 0 on if address is all-zeros, -1 if not all zeros or on failure. 268 */ 269 static int 270 addr_is_all0s(const struct xaddr *a) 271 { 272 int i; 273 274 switch (a->af) { 275 case AF_INET: 276 return (a->v4.s_addr == 0 ? 0 : -1); 277 case AF_INET6:; 278 for (i = 0; i < 4; i++) 279 if (a->addr32[i] != 0) 280 return (-1); 281 return (0); 282 default: 283 return (-1); 284 } 285 } 286 287 /* 288 * Test whether host portion of address 'a', as determined by 'masklen' 289 * is all zeros. 290 * Returns 0 on if host portion of address is all-zeros, 291 * -1 if not all zeros or on failure. 292 */ 293 static int 294 addr_host_is_all0s(const struct xaddr *a, u_int masklen) 295 { 296 struct xaddr tmp_addr, tmp_mask, tmp_result; 297 298 memcpy(&tmp_addr, a, sizeof(tmp_addr)); 299 if (addr_hostmask(a->af, masklen, &tmp_mask) == -1) 300 return (-1); 301 if (addr_and(&tmp_result, &tmp_addr, &tmp_mask) == -1) 302 return (-1); 303 return (addr_is_all0s(&tmp_result)); 304 } 305 306 /* 307 * Parse a CIDR address (x.x.x.x/y or xxxx:yyyy::/z). 308 * Return -1 on parse error, -2 on inconsistency or 0 on success. 309 */ 310 static int 311 addr_pton_cidr(const char *p, struct xaddr *n, u_int *l) 312 { 313 struct xaddr tmp; 314 unsigned int masklen = 999; 315 char addrbuf[64], *mp, *cp; 316 317 /* Don't modify argument */ 318 if (p == NULL || strlcpy(addrbuf, p, sizeof(addrbuf)) >= sizeof(addrbuf)) 319 return -1; 320 321 if ((mp = strchr(addrbuf, '/')) != NULL) { 322 *mp = '\0'; 323 mp++; 324 masklen = strtoul(mp, &cp, 10); 325 if (*mp == '\0' || *cp != '\0' || masklen > 128) 326 return -1; 327 } 328 329 if (addr_pton(addrbuf, &tmp) == -1) 330 return -1; 331 332 if (mp == NULL) 333 masklen = addr_unicast_masklen(tmp.af); 334 if (masklen_valid(tmp.af, masklen) == -1) 335 return -2; 336 if (addr_host_is_all0s(&tmp, masklen) != 0) 337 return -2; 338 339 if (n != NULL) 340 memcpy(n, &tmp, sizeof(*n)); 341 if (l != NULL) 342 *l = masklen; 343 344 return 0; 345 } 346 347 static int 348 addr_netmatch(const struct xaddr *host, const struct xaddr *net, u_int masklen) 349 { 350 struct xaddr tmp_mask, tmp_result; 351 352 if (host->af != net->af) 353 return -1; 354 355 if (addr_netmask(host->af, masklen, &tmp_mask) == -1) 356 return -1; 357 if (addr_and(&tmp_result, host, &tmp_mask) == -1) 358 return -1; 359 return addr_cmp(&tmp_result, net); 360 } 361 362 /* 363 * Match "addr" against list pattern list "_list", which may contain a 364 * mix of CIDR addresses and old-school wildcards. 365 * 366 * If addr is NULL, then no matching is performed, but _list is parsed 367 * and checked for well-formedness. 368 * 369 * Returns 1 on match found (never returned when addr == NULL). 370 * Returns 0 on if no match found, or no errors found when addr == NULL. 371 * Returns -1 on negated match found (never returned when addr == NULL). 372 * Returns -2 on invalid list entry. 373 */ 374 int 375 addr_match_list(const char *addr, const char *_list) 376 { 377 char *list, *cp, *o; 378 struct xaddr try_addr, match_addr; 379 u_int masklen, neg; 380 int ret = 0, r; 381 382 if (addr != NULL && addr_pton(addr, &try_addr) != 0) { 383 debug2("%s: couldn't parse address %.100s", __func__, addr); 384 return 0; 385 } 386 if ((o = list = strdup(_list)) == NULL) 387 return -1; 388 while ((cp = strsep(&list, ",")) != NULL) { 389 neg = *cp == '!'; 390 if (neg) 391 cp++; 392 if (*cp == '\0') { 393 ret = -2; 394 break; 395 } 396 /* Prefer CIDR address matching */ 397 r = addr_pton_cidr(cp, &match_addr, &masklen); 398 if (r == -2) { 399 debug2("%s: inconsistent mask length for " 400 "match network \"%.100s\"", __func__, cp); 401 ret = -2; 402 break; 403 } else if (r == 0) { 404 if (addr != NULL && addr_netmatch(&try_addr, 405 &match_addr, masklen) == 0) { 406 foundit: 407 if (neg) { 408 ret = -1; 409 break; 410 } 411 ret = 1; 412 } 413 continue; 414 } else { 415 /* If CIDR parse failed, try wildcard string match */ 416 if (addr != NULL && match_pattern(addr, cp) == 1) 417 goto foundit; 418 } 419 } 420 free(o); 421 422 return ret; 423 } 424 425 /* 426 * Match "addr" against list CIDR list "_list". Lexical wildcards and 427 * negation are not supported. If "addr" == NULL, will verify structure 428 * of "_list". 429 * 430 * Returns 1 on match found (never returned when addr == NULL). 431 * Returns 0 on if no match found, or no errors found when addr == NULL. 432 * Returns -1 on error 433 */ 434 int 435 addr_match_cidr_list(const char *addr, const char *_list) 436 { 437 char *list, *cp, *o; 438 struct xaddr try_addr, match_addr; 439 u_int masklen; 440 int ret = 0, r; 441 442 if (addr != NULL && addr_pton(addr, &try_addr) != 0) { 443 debug2("%s: couldn't parse address %.100s", __func__, addr); 444 return 0; 445 } 446 if ((o = list = strdup(_list)) == NULL) 447 return -1; 448 while ((cp = strsep(&list, ",")) != NULL) { 449 if (*cp == '\0') { 450 error("%s: empty entry in list \"%.100s\"", 451 __func__, o); 452 ret = -1; 453 break; 454 } 455 456 /* 457 * NB. This function is called in pre-auth with untrusted data, 458 * so be extra paranoid about junk reaching getaddrino (via 459 * addr_pton_cidr). 460 */ 461 462 /* Stop junk from reaching getaddrinfo. +3 is for masklen */ 463 if (strlen(cp) > INET6_ADDRSTRLEN + 3) { 464 error("%s: list entry \"%.100s\" too long", 465 __func__, cp); 466 ret = -1; 467 break; 468 } 469 #define VALID_CIDR_CHARS "0123456789abcdefABCDEF.:/" 470 if (strspn(cp, VALID_CIDR_CHARS) != strlen(cp)) { 471 error("%s: list entry \"%.100s\" contains invalid " 472 "characters", __func__, cp); 473 ret = -1; 474 } 475 476 /* Prefer CIDR address matching */ 477 r = addr_pton_cidr(cp, &match_addr, &masklen); 478 if (r == -1) { 479 error("Invalid network entry \"%.100s\"", cp); 480 ret = -1; 481 break; 482 } else if (r == -2) { 483 error("Inconsistent mask length for " 484 "network \"%.100s\"", cp); 485 ret = -1; 486 break; 487 } else if (r == 0 && addr != NULL) { 488 if (addr_netmatch(&try_addr, &match_addr, 489 masklen) == 0) 490 ret = 1; 491 continue; 492 } 493 } 494 free(o); 495 496 return ret; 497 } 498