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1/* $OpenBSD: addrmatch.c,v 1.3 2008/06/10 23:06:19 djm 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
35struct 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
50static int
51addr_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
63static inline int
64masklen_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 */
80static int
81addr_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 */
114static int
115addr_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 */
145static int
146addr_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 */
172static int
173addr_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 */
201static int
202addr_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 */
229static int
230addr_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 */
255static int
256addr_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 */
267static int
268addr_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 */
291static int
292addr_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 */
308static int
309addr_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
345static int
346addr_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 */
372int
373addr_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}