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 /* LINTED E_BAD_PTR_CAST_ALIGN */
85 struct sockaddr_in *in4 = (struct sockaddr_in *)sa;
86 /* LINTED E_BAD_PTR_CAST_ALIGN */
87 struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)sa;
88
89 memset(xa, '\0', sizeof(*xa));
90
91 switch (sa->sa_family) {
92 case AF_INET:
93 if (slen < sizeof(*in4))
94 return -1;
95 xa->af = AF_INET;
96 memcpy(&xa->v4, &in4->sin_addr, sizeof(xa->v4));
97 break;
98 case AF_INET6:
99 if (slen < sizeof(*in6))
100 return -1;
101 xa->af = AF_INET6;
102 memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6));
103 #ifdef HAVE_STRUCT_SOCKADDR_IN6_SIN6_SCOPE_ID
104 xa->scope_id = in6->sin6_scope_id;
105 #endif
106 break;
107 default:
108 return -1;
109 }
110
111 return 0;
112 }
113
114 /*
115 * Calculate a netmask of length 'l' for address family 'af' and
116 * store it in 'n'.
117 * Returns 0 on success, -1 on failure.
118 */
119 static int
120 addr_netmask(int af, u_int l, struct xaddr *n)
121 {
122 int i;
123
124 if (masklen_valid(af, l) != 0 || n == NULL)
125 return -1;
126
127 memset(n, '\0', sizeof(*n));
128 switch (af) {
129 case AF_INET:
130 n->af = AF_INET;
131 n->v4.s_addr = htonl((0xffffffff << (32 - l)) & 0xffffffff);
132 return 0;
133 case AF_INET6:
134 n->af = AF_INET6;
135 for (i = 0; i < 4 && l >= 32; i++, l -= 32)
136 n->addr32[i] = 0xffffffffU;
137 if (i < 4 && l != 0)
138 n->addr32[i] = htonl((0xffffffff << (32 - l)) &
139 0xffffffff);
140 return 0;
141 default:
142 return -1;
143 }
144 }
145
146 /*
147 * Perform logical AND of addresses 'a' and 'b', storing result in 'dst'.
148 * Returns 0 on success, -1 on failure.
149 */
150 static int
151 addr_and(struct xaddr *dst, const struct xaddr *a, const struct xaddr *b)
152 {
153 int i;
154
155 if (dst == NULL || a == NULL || b == NULL || a->af != b->af)
156 return -1;
157
158 memcpy(dst, a, sizeof(*dst));
159 switch (a->af) {
160 case AF_INET:
161 dst->v4.s_addr &= b->v4.s_addr;
162 return 0;
163 case AF_INET6:
164 dst->scope_id = a->scope_id;
165 for (i = 0; i < 4; i++)
166 dst->addr32[i] &= b->addr32[i];
167 return 0;
168 default:
169 return -1;
170 }
171 }
172
173 /*
174 * Compare addresses 'a' and 'b'
175 * Return 0 if addresses are identical, -1 if (a < b) or 1 if (a > b)
176 */
177 static int
178 addr_cmp(const struct xaddr *a, const struct xaddr *b)
179 {
180 int i;
181
182 if (a->af != b->af)
183 return a->af == AF_INET6 ? 1 : -1;
184
185 switch (a->af) {
186 case AF_INET:
187 if (a->v4.s_addr == b->v4.s_addr)
188 return 0;
189 return ntohl(a->v4.s_addr) > ntohl(b->v4.s_addr) ? 1 : -1;
190 case AF_INET6:
191 for (i = 0; i < 16; i++)
192 if (a->addr8[i] - b->addr8[i] != 0)
193 return a->addr8[i] > b->addr8[i] ? 1 : -1;
194 if (a->scope_id == b->scope_id)
195 return 0;
196 return a->scope_id > b->scope_id ? 1 : -1;
197 default:
198 return -1;
199 }
200 }
201
202 /*
203 * Parse string address 'p' into 'n'
204 * Returns 0 on success, -1 on failure.
205 */
206 static int
207 addr_pton(const char *p, struct xaddr *n)
208 {
209 struct addrinfo hints, *ai;
210
211 memset(&hints, '\0', sizeof(hints));
212 hints.ai_flags = AI_NUMERICHOST;
213
214 if (p == NULL || getaddrinfo(p, NULL, &hints, &ai) != 0)
215 return -1;
216
217 if (ai == NULL || ai->ai_addr == NULL)
218 return -1;
219
220 if (n != NULL &&
221 addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen, n) == -1) {
222 freeaddrinfo(ai);
223 return -1;
224 }
225
226 freeaddrinfo(ai);
227 return 0;
228 }
229
230 /*
231 * Perform bitwise negation of address
232 * Returns 0 on success, -1 on failure.
233 */
234 static int
235 addr_invert(struct xaddr *n)
236 {
237 int i;
238
239 if (n == NULL)
240 return (-1);
241
242 switch (n->af) {
243 case AF_INET:
244 n->v4.s_addr = ~n->v4.s_addr;
245 return (0);
246 case AF_INET6:
247 for (i = 0; i < 4; i++)
248 n->addr32[i] = ~n->addr32[i];
249 return (0);
250 default:
251 return (-1);
252 }
253 }
254
255 /*
256 * Calculate a netmask of length 'l' for address family 'af' and
257 * store it in 'n'.
258 * Returns 0 on success, -1 on failure.
259 */
260 static int
261 addr_hostmask(int af, u_int l, struct xaddr *n)
262 {
263 if (addr_netmask(af, l, n) == -1 || addr_invert(n) == -1)
264 return (-1);
265 return (0);
266 }
267
268 /*
269 * Test whether address 'a' is all zeros (i.e. 0.0.0.0 or ::)
270 * Returns 0 on if address is all-zeros, -1 if not all zeros or on failure.
271 */
272 static int
273 addr_is_all0s(const struct xaddr *a)
274 {
275 int i;
276
277 switch (a->af) {
278 case AF_INET:
279 return (a->v4.s_addr == 0 ? 0 : -1);
280 case AF_INET6:;
281 for (i = 0; i < 4; i++)
282 if (a->addr32[i] != 0)
283 return (-1);
284 return (0);
285 default:
286 return (-1);
287 }
288 }
289
290 /*
291 * Test whether host portion of address 'a', as determined by 'masklen'
292 * is all zeros.
293 * Returns 0 on if host portion of address is all-zeros,
294 * -1 if not all zeros or on failure.
295 */
296 static int
297 addr_host_is_all0s(const struct xaddr *a, u_int masklen)
298 {
299 struct xaddr tmp_addr, tmp_mask, tmp_result;
300
301 memcpy(&tmp_addr, a, sizeof(tmp_addr));
302 if (addr_hostmask(a->af, masklen, &tmp_mask) == -1)
303 return (-1);
304 if (addr_and(&tmp_result, &tmp_addr, &tmp_mask) == -1)
305 return (-1);
306 return (addr_is_all0s(&tmp_result));
307 }
308
309 /*
310 * Parse a CIDR address (x.x.x.x/y or xxxx:yyyy::/z).
311 * Return -1 on parse error, -2 on inconsistency or 0 on success.
312 */
313 static int
314 addr_pton_cidr(const char *p, struct xaddr *n, u_int *l)
315 {
316 struct xaddr tmp;
317 long unsigned int masklen = 999;
318 char addrbuf[64], *mp, *cp;
319
320 /* Don't modify argument */
321 if (p == NULL || strlcpy(addrbuf, p, sizeof(addrbuf)) > sizeof(addrbuf))
322 return -1;
323
324 if ((mp = strchr(addrbuf, '/')) != NULL) {
325 *mp = '\0';
326 mp++;
327 masklen = strtoul(mp, &cp, 10);
328 if (*mp == '\0' || *cp != '\0' || masklen > 128)
329 return -1;
330 }
331
332 if (addr_pton(addrbuf, &tmp) == -1)
333 return -1;
334
335 if (mp == NULL)
336 masklen = addr_unicast_masklen(tmp.af);
337 if (masklen_valid(tmp.af, masklen) == -1)
338 return -2;
339 if (addr_host_is_all0s(&tmp, masklen) != 0)
340 return -2;
341
342 if (n != NULL)
343 memcpy(n, &tmp, sizeof(*n));
344 if (l != NULL)
345 *l = masklen;
346
347 return 0;
348 }
349
350 static int
351 addr_netmatch(const struct xaddr *host, const struct xaddr *net, u_int masklen)
352 {
353 struct xaddr tmp_mask, tmp_result;
354
355 if (host->af != net->af)
356 return -1;
357
358 if (addr_netmask(host->af, masklen, &tmp_mask) == -1)
359 return -1;
360 if (addr_and(&tmp_result, host, &tmp_mask) == -1)
361 return -1;
362 return addr_cmp(&tmp_result, net);
363 }
364
365 /*
366 * Match "addr" against list pattern list "_list", which may contain a
367 * mix of CIDR addresses and old-school wildcards.
368 *
369 * If addr is NULL, then no matching is performed, but _list is parsed
370 * and checked for well-formedness.
371 *
372 * Returns 1 on match found (never returned when addr == NULL).
373 * Returns 0 on if no match found, or no errors found when addr == NULL.
374 * Returns -1 on negated match found (never returned when addr == NULL).
375 * Returns -2 on invalid list entry.
376 */
377 int
378 addr_match_list(const char *addr, const char *_list)
379 {
380 char *list, *cp, *o;
381 struct xaddr try_addr, match_addr;
382 u_int masklen, neg;
383 int ret = 0, r;
384
385 if (addr != NULL && addr_pton(addr, &try_addr) != 0) {
386 debug2("%s: couldn't parse address %.100s", __func__, addr);
387 return 0;
388 }
389 if ((o = list = strdup(_list)) == NULL)
390 return -1;
391 while ((cp = strsep(&list, ",")) != NULL) {
392 neg = *cp == '!';
393 if (neg)
394 cp++;
395 if (*cp == '\0') {
396 ret = -2;
397 break;
398 }
399 /* Prefer CIDR address matching */
400 r = addr_pton_cidr(cp, &match_addr, &masklen);
401 if (r == -2) {
402 error("Inconsistent mask length for "
403 "network \"%.100s\"", cp);
404 ret = -2;
405 break;
406 } else if (r == 0) {
407 if (addr != NULL && addr_netmatch(&try_addr,
408 &match_addr, masklen) == 0) {
409 foundit:
410 if (neg) {
411 ret = -1;
412 break;
413 }
414 ret = 1;
415 }
416 continue;
417 } else {
418 /* If CIDR parse failed, try wildcard string match */
419 if (addr != NULL && match_pattern(addr, cp) == 1)
420 goto foundit;
421 }
422 }
423 xfree(o);
424
425 return ret;
426 }