crypto/dist/ssh/addrmatch.c

   1 /*      $NetBSD$        */
   2 /*      $OpenBSD: addrmatch.c,v 1.3 2008/06/10 23:06:19 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 #include "includes.h"
  20 __RCSID("$NetBSD$");
  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 < 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 < sizeof(*in6))
  97                         return -1;
  98                 xa->af = AF_INET6;
  99                 memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6));
 100                 xa->scope_id = in6->sin6_scope_id;
 101                 break;
 102         default:
 103                 return -1;
 104         }
 105
 106         return 0;
 107 }
 108
 109 /*
 110  * Calculate a netmask of length 'l' for address family 'af' and
 111  * store it in 'n'.
 112  * Returns 0 on success, -1 on failure.
 113  */
 114 static int
 115 addr_netmask(int af, u_int l, struct xaddr *n)
 116 {
 117         int i;
 118
 119         if (masklen_valid(af, l) != 0 || n == NULL)
 120                 return -1;
 121
 122         memset(n, '\0', sizeof(*n));
 123         switch (af) {
 124         case AF_INET:
 125                 n->af = AF_INET;
 126                 n->v4.s_addr = htonl((0xffffffff << (32 - l)) & 0xffffffff);
 127                 return 0;
 128         case AF_INET6:
 129                 n->af = AF_INET6;
 130                 for (i = 0; i < 4 && l >= 32; i++, l -= 32)
 131                         n->addr32[i] = 0xffffffffU;
 132                 if (i < 4 && l != 0)
 133                         n->addr32[i] = htonl((0xffffffff << (32 - l)) &
 134                             0xffffffff);
 135                 return 0;
 136         default:
 137                 return -1;
 138         }
 139 }
 140
 141 /*
 142  * Perform logical AND of addresses 'a' and 'b', storing result in 'dst'.
 143  * Returns 0 on success, -1 on failure.
 144  */
 145 static int
 146 addr_and(struct xaddr *dst, const struct xaddr *a, const struct xaddr *b)
 147 {
 148         int i;
 149
 150         if (dst == NULL || a == NULL || b == NULL || a->af != b->af)
 151                 return -1;
 152
 153         memcpy(dst, a, sizeof(*dst));
 154         switch (a->af) {
 155         case AF_INET:
 156                 dst->v4.s_addr &= b->v4.s_addr;
 157                 return 0;
 158         case AF_INET6:
 159                 dst->scope_id = a->scope_id;
 160                 for (i = 0; i < 4; i++)
 161                         dst->addr32[i] &= b->addr32[i];
 162                 return 0;
 163         default:
 164                 return -1;
 165         }
 166 }
 167
 168 /*
 169  * Compare addresses 'a' and 'b'
 170  * Return 0 if addresses are identical, -1 if (a < b) or 1 if (a > b)
 171  */
 172 static int
 173 addr_cmp(const struct xaddr *a, const struct xaddr *b)
 174 {
 175         int i;
 176
 177         if (a->af != b->af)
 178                 return a->af == AF_INET6 ? 1 : -1;
 179
 180         switch (a->af) {
 181         case AF_INET:
 182                 if (a->v4.s_addr == b->v4.s_addr)
 183                         return 0;
 184                 return ntohl(a->v4.s_addr) > ntohl(b->v4.s_addr) ? 1 : -1;
 185         case AF_INET6:
 186                 for (i = 0; i < 16; i++)
 187                         if (a->addr8[i] - b->addr8[i] != 0)
 188                                 return a->addr8[i] > b->addr8[i] ? 1 : -1;
 189                 if (a->scope_id == b->scope_id)
 190                         return 0;
 191                 return a->scope_id > b->scope_id ? 1 : -1;
 192         default:
 193                 return -1;
 194         }
 195 }
 196
 197 /*
 198  * Parse string address 'p' into 'n'
 199  * Returns 0 on success, -1 on failure.
 200  */
 201 static int
 202 addr_pton(const char *p, struct xaddr *n)
 203 {
 204         struct addrinfo hints, *ai;
 205
 206         memset(&hints, '\0', sizeof(hints));
 207         hints.ai_flags = AI_NUMERICHOST;
 208
 209         if (p == NULL || getaddrinfo(p, NULL, &hints, &ai) != 0)
 210                 return -1;
 211
 212         if (ai == NULL || ai->ai_addr == NULL)
 213                 return -1;
 214
 215         if (n != NULL &&
 216             addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen, n) == -1) {
 217                 freeaddrinfo(ai);
 218                 return -1;
 219         }
 220
 221         freeaddrinfo(ai);
 222         return 0;
 223 }
 224
 225 /*
 226  * Perform bitwise negation of address
 227  * Returns 0 on success, -1 on failure.
 228  */
 229 static int
 230 addr_invert(struct xaddr *n)
 231 {
 232         int i;
 233
 234         if (n == NULL)
 235                 return (-1);
 236
 237         switch (n->af) {
 238         case AF_INET:
 239                 n->v4.s_addr = ~n->v4.s_addr;
 240                 return (0);
 241         case AF_INET6:
 242                 for (i = 0; i < 4; i++)
 243                         n->addr32[i] = ~n->addr32[i];
 244                 return (0);
 245         default:
 246                 return (-1);
 247         }
 248 }
 249
 250 /*
 251  * Calculate a netmask of length 'l' for address family 'af' and
 252  * store it in 'n'.
 253  * Returns 0 on success, -1 on failure.
 254  */
 255 static int
 256 addr_hostmask(int af, u_int l, struct xaddr *n)
 257 {
 258         if (addr_netmask(af, l, n) == -1 || addr_invert(n) == -1)
 259                 return (-1);
 260         return (0);
 261 }
 262
 263 /*
 264  * Test whether address 'a' is all zeros (i.e. 0.0.0.0 or ::)
 265  * Returns 0 on if address is all-zeros, -1 if not all zeros or on failure.
 266  */
 267 static int
 268 addr_is_all0s(const struct xaddr *a)
 269 {
 270         int i;
 271
 272         switch (a->af) {
 273         case AF_INET:
 274                 return (a->v4.s_addr == 0 ? 0 : -1);
 275         case AF_INET6:;
 276                 for (i = 0; i < 4; i++)
 277                         if (a->addr32[i] != 0)
 278                                 return (-1);
 279                 return (0);
 280         default:
 281                 return (-1);
 282         }
 283 }
 284
 285 /*
 286  * Test whether host portion of address 'a', as determined by 'masklen'
 287  * is all zeros.
 288  * Returns 0 on if host portion of address is all-zeros,
 289  * -1 if not all zeros or on failure.
 290  */
 291 static int
 292 addr_host_is_all0s(const struct xaddr *a, u_int masklen)
 293 {
 294         struct xaddr tmp_addr, tmp_mask, tmp_result;
 295
 296         memcpy(&tmp_addr, a, sizeof(tmp_addr));
 297         if (addr_hostmask(a->af, masklen, &tmp_mask) == -1)
 298                 return (-1);
 299         if (addr_and(&tmp_result, &tmp_addr, &tmp_mask) == -1)
 300                 return (-1);
 301         return (addr_is_all0s(&tmp_result));
 302 }
 303
 304 /*
 305  * Parse a CIDR address (x.x.x.x/y or xxxx:yyyy::/z).
 306  * Return -1 on parse error, -2 on inconsistency or 0 on success.
 307  */
 308 static int
 309 addr_pton_cidr(const char *p, struct xaddr *n, u_int *l)
 310 {
 311         struct xaddr tmp;
 312         long unsigned int masklen = 999;
 313         char addrbuf[64], *mp, *cp;
 314
 315         /* Don't modify argument */
 316         if (p == NULL || strlcpy(addrbuf, p, sizeof(addrbuf)) > sizeof(addrbuf))
 317                 return -1;
 318
 319         if ((mp = strchr(addrbuf, '/')) != NULL) {
 320                 *mp = '\0';
 321                 mp++;
 322                 masklen = strtoul(mp, &cp, 10);
 323                 if (*mp == '\0' || *cp != '\0' || masklen > 128)
 324                         return -1;
 325         }
 326
 327         if (addr_pton(addrbuf, &tmp) == -1)
 328                 return -1;
 329
 330         if (mp == NULL)
 331                 masklen = addr_unicast_masklen(tmp.af);
 332         if (masklen_valid(tmp.af, masklen) == -1)
 333                 return -2;
 334         if (addr_host_is_all0s(&tmp, masklen) != 0)
 335                 return -2;
 336
 337         if (n != NULL)
 338                 memcpy(n, &tmp, sizeof(*n));
 339         if (l != NULL)
 340                 *l = masklen;
 341
 342         return 0;
 343 }
 344
 345 static int
 346 addr_netmatch(const struct xaddr *host, const struct xaddr *net, u_int masklen)
 347 {
 348         struct xaddr tmp_mask, tmp_result;
 349
 350         if (host->af != net->af)
 351                 return -1;
 352
 353         if (addr_netmask(host->af, masklen, &tmp_mask) == -1)
 354                 return -1;
 355         if (addr_and(&tmp_result, host, &tmp_mask) == -1)
 356                 return -1;
 357         return addr_cmp(&tmp_result, net);
 358 }
 359
 360 /*
 361  * Match "addr" against list pattern list "_list", which may contain a
 362  * mix of CIDR addresses and old-school wildcards.
 363  *
 364  * If addr is NULL, then no matching is performed, but _list is parsed
 365  * and checked for well-formedness.
 366  *
 367  * Returns 1 on match found (never returned when addr == NULL).
 368  * Returns 0 on if no match found, or no errors found when addr == NULL.
 369  * Returns -1 on negated match found (never returned when addr == NULL).
 370  * Returns -2 on invalid list entry.
 371  */
 372 int
 373 addr_match_list(const char *addr, const char *_list)
 374 {
 375         char *list, *cp, *o;
 376         struct xaddr try_addr, match_addr;
 377         u_int masklen, neg;
 378         int ret = 0, r;
 379
 380         if (addr != NULL && addr_pton(addr, &try_addr) != 0) {
 381                 debug2("%s: couldn't parse address %.100s", __func__, addr);
 382                 return 0;
 383         }
 384         if ((o = list = strdup(_list)) == NULL)
 385                 return -1;
 386         while ((cp = strsep(&list, ",")) != NULL) {
 387                 neg = *cp == '!';
 388                 if (neg)
 389                         cp++;
 390                 if (*cp == '\0') {
 391                         ret = -2;
 392                         break;
 393                 }
 394                 /* Prefer CIDR address matching */
 395                 r = addr_pton_cidr(cp, &match_addr, &masklen);
 396                 if (r == -2) {
 397                         error("Inconsistent mask length for "
 398                             "network \"%.100s\"", cp);
 399                         ret = -2;
 400                         break;
 401                 } else if (r == 0) {
 402                         if (addr != NULL && addr_netmatch(&try_addr,
 403                            &match_addr, masklen) == 0) {
 404  foundit:
 405                                 if (neg) {
 406                                         ret = -1;
 407                                         break;
 408                                 }
 409                                 ret = 1;
 410                         }
 411                         continue;
 412                 } else {
 413                         /* If CIDR parse failed, try wildcard string match */
 414                         if (addr != NULL && match_pattern(addr, cp) == 1)
 415                                 goto foundit;
 416                 }
 417         }
 418         free(o);
 419
 420         return ret;
 421 }