crypto/external/bsd/openssh/dist/addrmatch.c

   1 /*      $NetBSD$        */
   2 /*      $OpenBSD: addrmatch.c,v 1.4 2008/12/10 03:55:20 stevesk 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 1.2 2009/02/16 20:53:54 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 #include "xmalloc.h"
  36
  37 struct xaddr {
  38         sa_family_t     af;
  39         union {
  40                 struct in_addr          v4;
  41                 struct in6_addr         v6;
  42                 u_int8_t                addr8[16];
  43                 u_int32_t               addr32[4];
  44         } xa;               /* 128-bit address */
  45         u_int32_t       scope_id;       /* iface scope id for v6 */
  46 #define v4      xa.v4
  47 #define v6      xa.v6
  48 #define addr8   xa.addr8
  49 #define addr32  xa.addr32
  50 };
  51
  52 static int
  53 addr_unicast_masklen(int af)
  54 {
  55         switch (af) {
  56         case AF_INET:
  57                 return 32;
  58         case AF_INET6:
  59                 return 128;
  60         default:
  61                 return -1;
  62         }
  63 }
  64
  65 static inline int
  66 masklen_valid(int af, u_int masklen)
  67 {
  68         switch (af) {
  69         case AF_INET:
  70                 return masklen <= 32 ? 0 : -1;
  71         case AF_INET6:
  72                 return masklen <= 128 ? 0 : -1;
  73         default:
  74                 return -1;
  75         }
  76 }
  77
  78 /*
  79  * Convert struct sockaddr to struct xaddr
  80  * Returns 0 on success, -1 on failure.
  81  */
  82 static int
  83 addr_sa_to_xaddr(struct sockaddr *sa, socklen_t slen, struct xaddr *xa)
  84 {
  85         struct sockaddr_in *in4 = (struct sockaddr_in *)sa;
  86         struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)sa;
  87
  88         memset(xa, '\0', sizeof(*xa));
  89
  90         switch (sa->sa_family) {
  91         case AF_INET:
  92                 if (slen < sizeof(*in4))
  93                         return -1;
  94                 xa->af = AF_INET;
  95                 memcpy(&xa->v4, &in4->sin_addr, sizeof(xa->v4));
  96                 break;
  97         case AF_INET6:
  98                 if (slen < sizeof(*in6))
  99                         return -1;
 100                 xa->af = AF_INET6;
 101                 memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6));
 102                 xa->scope_id = in6->sin6_scope_id;
 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                 n->v4.s_addr = htonl((0xffffffff << (32 - l)) & 0xffffffff);
 129                 return 0;
 130         case AF_INET6:
 131                 n->af = AF_INET6;
 132                 for (i = 0; i < 4 && l >= 32; i++, l -= 32)
 133                         n->addr32[i] = 0xffffffffU;
 134                 if (i < 4 && l != 0)
 135                         n->addr32[i] = htonl((0xffffffff << (32 - l)) &
 136                             0xffffffff);
 137                 return 0;
 138         default:
 139                 return -1;
 140         }
 141 }
 142
 143 /*
 144  * Perform logical AND of addresses 'a' and 'b', storing result in 'dst'.
 145  * Returns 0 on success, -1 on failure.
 146  */
 147 static int
 148 addr_and(struct xaddr *dst, const struct xaddr *a, const struct xaddr *b)
 149 {
 150         int i;
 151
 152         if (dst == NULL || a == NULL || b == NULL || a->af != b->af)
 153                 return -1;
 154
 155         memcpy(dst, a, sizeof(*dst));
 156         switch (a->af) {
 157         case AF_INET:
 158                 dst->v4.s_addr &= b->v4.s_addr;
 159                 return 0;
 160         case AF_INET6:
 161                 dst->scope_id = a->scope_id;
 162                 for (i = 0; i < 4; i++)
 163                         dst->addr32[i] &= b->addr32[i];
 164                 return 0;
 165         default:
 166                 return -1;
 167         }
 168 }
 169
 170 /*
 171  * Compare addresses 'a' and 'b'
 172  * Return 0 if addresses are identical, -1 if (a < b) or 1 if (a > b)
 173  */
 174 static int
 175 addr_cmp(const struct xaddr *a, const struct xaddr *b)
 176 {
 177         int i;
 178
 179         if (a->af != b->af)
 180                 return a->af == AF_INET6 ? 1 : -1;
 181
 182         switch (a->af) {
 183         case AF_INET:
 184                 if (a->v4.s_addr == b->v4.s_addr)
 185                         return 0;
 186                 return ntohl(a->v4.s_addr) > ntohl(b->v4.s_addr) ? 1 : -1;
 187         case AF_INET6:
 188                 for (i = 0; i < 16; i++)
 189                         if (a->addr8[i] - b->addr8[i] != 0)
 190                                 return a->addr8[i] > b->addr8[i] ? 1 : -1;
 191                 if (a->scope_id == b->scope_id)
 192                         return 0;
 193                 return a->scope_id > b->scope_id ? 1 : -1;
 194         default:
 195                 return -1;
 196         }
 197 }
 198
 199 /*
 200  * Parse string address 'p' into 'n'
 201  * Returns 0 on success, -1 on failure.
 202  */
 203 static int
 204 addr_pton(const char *p, struct xaddr *n)
 205 {
 206         struct addrinfo hints, *ai;
 207
 208         memset(&hints, '\0', sizeof(hints));
 209         hints.ai_flags = AI_NUMERICHOST;
 210
 211         if (p == NULL || getaddrinfo(p, NULL, &hints, &ai) != 0)
 212                 return -1;
 213
 214         if (ai == NULL || ai->ai_addr == NULL)
 215                 return -1;
 216
 217         if (n != NULL &&
 218             addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen, n) == -1) {
 219                 freeaddrinfo(ai);
 220                 return -1;
 221         }
 222
 223         freeaddrinfo(ai);
 224         return 0;
 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         long 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                         error("Inconsistent mask length for "
 400                             "network \"%.100s\"", 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         xfree(o);
 421
 422         return ret;
 423 }