crypto/openssh/addrmatch.c

   1 /*      $OpenBSD: addrmatch.c,v 1.4 2008/12/10 03:55:20 stevesk 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 #include "xmalloc.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 *)sa;
  85         struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)sa;
  86
  87         memset(xa, '\0', sizeof(*xa));
  88
  89         switch (sa->sa_family) {
  90         case AF_INET:
  91                 if (slen < 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 < sizeof(*in6))
  98                         return -1;
  99                 xa->af = AF_INET6;
 100                 memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6));
 101 #ifdef HAVE_STRUCT_SOCKADDR_IN6_SIN6_SCOPE_ID
 102                 xa->scope_id = in6->sin6_scope_id;
 103 #endif
 104                 break;
 105         default:
 106                 return -1;
 107         }
 108
 109         return 0;
 110 }
 111
 112 /*
 113  * Calculate a netmask of length 'l' for address family 'af' and
 114  * store it in 'n'.
 115  * Returns 0 on success, -1 on failure.
 116  */
 117 static int
 118 addr_netmask(int af, u_int l, struct xaddr *n)
 119 {
 120         int i;
 121
 122         if (masklen_valid(af, l) != 0 || n == NULL)
 123                 return -1;
 124
 125         memset(n, '\0', sizeof(*n));
 126         switch (af) {
 127         case AF_INET:
 128                 n->af = AF_INET;
 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         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                         error("Inconsistent mask length for "
 401                             "network \"%.100s\"", 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         xfree(o);
 422
 423         return ret;
 424 }