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djm@openbsd.orga5ad3a92016-09-21 16:55:42 +00001/* $OpenBSD: addrmatch.c,v 1.13 2016/09/21 16:55:42 djm Exp $ */
Darren Tucker7a3935d2008-06-10 22:59:10 +10002
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:
Darren Tucker7eee3582014-01-19 22:37:02 +110090 if (slen < (socklen_t)sizeof(*in4))
Darren Tucker7a3935d2008-06-10 22:59:10 +100091 return -1;
92 xa->af = AF_INET;
93 memcpy(&xa->v4, &in4->sin_addr, sizeof(xa->v4));
94 break;
95 case AF_INET6:
Darren Tucker7eee3582014-01-19 22:37:02 +110096 if (slen < (socklen_t)sizeof(*in6))
Darren Tucker7a3935d2008-06-10 22:59:10 +100097 return -1;
98 xa->af = AF_INET6;
99 memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6));
Tim Rice0f4d2c02008-11-18 21:26:41 -0800100#ifdef HAVE_STRUCT_SOCKADDR_IN6_SIN6_SCOPE_ID
Darren Tucker7a3935d2008-06-10 22:59:10 +1000101 xa->scope_id = in6->sin6_scope_id;
Tim Rice0f4d2c02008-11-18 21:26:41 -0800102#endif
Darren Tucker7a3935d2008-06-10 22:59:10 +1000103 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 */
116static int
117addr_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;
Damien Miller0a80ca12010-02-27 07:55:05 +1100128 if (l == 0)
129 return 0;
Darren Tucker7a3935d2008-06-10 22:59:10 +1000130 n->v4.s_addr = htonl((0xffffffff << (32 - l)) & 0xffffffff);
131 return 0;
132 case AF_INET6:
133 n->af = AF_INET6;
134 for (i = 0; i < 4 && l >= 32; i++, l -= 32)
135 n->addr32[i] = 0xffffffffU;
136 if (i < 4 && l != 0)
137 n->addr32[i] = htonl((0xffffffff << (32 - l)) &
138 0xffffffff);
139 return 0;
140 default:
141 return -1;
142 }
143}
144
145/*
146 * Perform logical AND of addresses 'a' and 'b', storing result in 'dst'.
147 * Returns 0 on success, -1 on failure.
148 */
149static int
150addr_and(struct xaddr *dst, const struct xaddr *a, const struct xaddr *b)
151{
152 int i;
153
154 if (dst == NULL || a == NULL || b == NULL || a->af != b->af)
155 return -1;
156
157 memcpy(dst, a, sizeof(*dst));
158 switch (a->af) {
159 case AF_INET:
160 dst->v4.s_addr &= b->v4.s_addr;
161 return 0;
162 case AF_INET6:
163 dst->scope_id = a->scope_id;
164 for (i = 0; i < 4; i++)
165 dst->addr32[i] &= b->addr32[i];
166 return 0;
167 default:
168 return -1;
169 }
170}
171
172/*
173 * Compare addresses 'a' and 'b'
174 * Return 0 if addresses are identical, -1 if (a < b) or 1 if (a > b)
175 */
176static int
177addr_cmp(const struct xaddr *a, const struct xaddr *b)
178{
179 int i;
180
181 if (a->af != b->af)
182 return a->af == AF_INET6 ? 1 : -1;
183
184 switch (a->af) {
185 case AF_INET:
186 if (a->v4.s_addr == b->v4.s_addr)
187 return 0;
188 return ntohl(a->v4.s_addr) > ntohl(b->v4.s_addr) ? 1 : -1;
189 case AF_INET6:
190 for (i = 0; i < 16; i++)
191 if (a->addr8[i] - b->addr8[i] != 0)
192 return a->addr8[i] > b->addr8[i] ? 1 : -1;
193 if (a->scope_id == b->scope_id)
194 return 0;
195 return a->scope_id > b->scope_id ? 1 : -1;
196 default:
197 return -1;
198 }
199}
200
201/*
202 * Parse string address 'p' into 'n'
203 * Returns 0 on success, -1 on failure.
204 */
205static int
206addr_pton(const char *p, struct xaddr *n)
207{
208 struct addrinfo hints, *ai;
209
210 memset(&hints, '\0', sizeof(hints));
211 hints.ai_flags = AI_NUMERICHOST;
212
213 if (p == NULL || getaddrinfo(p, NULL, &hints, &ai) != 0)
214 return -1;
215
216 if (ai == NULL || ai->ai_addr == NULL)
217 return -1;
218
219 if (n != NULL &&
220 addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen, n) == -1) {
221 freeaddrinfo(ai);
222 return -1;
223 }
224
225 freeaddrinfo(ai);
226 return 0;
227}
228
229/*
230 * Perform bitwise negation of address
231 * Returns 0 on success, -1 on failure.
232 */
233static int
234addr_invert(struct xaddr *n)
235{
236 int i;
237
238 if (n == NULL)
239 return (-1);
240
241 switch (n->af) {
242 case AF_INET:
243 n->v4.s_addr = ~n->v4.s_addr;
244 return (0);
245 case AF_INET6:
246 for (i = 0; i < 4; i++)
247 n->addr32[i] = ~n->addr32[i];
248 return (0);
249 default:
250 return (-1);
251 }
252}
253
254/*
255 * Calculate a netmask of length 'l' for address family 'af' and
256 * store it in 'n'.
257 * Returns 0 on success, -1 on failure.
258 */
259static int
260addr_hostmask(int af, u_int l, struct xaddr *n)
261{
262 if (addr_netmask(af, l, n) == -1 || addr_invert(n) == -1)
263 return (-1);
264 return (0);
265}
266
267/*
268 * Test whether address 'a' is all zeros (i.e. 0.0.0.0 or ::)
269 * Returns 0 on if address is all-zeros, -1 if not all zeros or on failure.
270 */
271static int
272addr_is_all0s(const struct xaddr *a)
273{
274 int i;
275
276 switch (a->af) {
277 case AF_INET:
278 return (a->v4.s_addr == 0 ? 0 : -1);
279 case AF_INET6:;
280 for (i = 0; i < 4; i++)
281 if (a->addr32[i] != 0)
282 return (-1);
283 return (0);
284 default:
285 return (-1);
286 }
287}
288
289/*
290 * Test whether host portion of address 'a', as determined by 'masklen'
291 * is all zeros.
292 * Returns 0 on if host portion of address is all-zeros,
293 * -1 if not all zeros or on failure.
294 */
295static int
296addr_host_is_all0s(const struct xaddr *a, u_int masklen)
297{
298 struct xaddr tmp_addr, tmp_mask, tmp_result;
299
300 memcpy(&tmp_addr, a, sizeof(tmp_addr));
301 if (addr_hostmask(a->af, masklen, &tmp_mask) == -1)
302 return (-1);
303 if (addr_and(&tmp_result, &tmp_addr, &tmp_mask) == -1)
304 return (-1);
305 return (addr_is_all0s(&tmp_result));
306}
307
308/*
309 * Parse a CIDR address (x.x.x.x/y or xxxx:yyyy::/z).
310 * Return -1 on parse error, -2 on inconsistency or 0 on success.
311 */
312static int
313addr_pton_cidr(const char *p, struct xaddr *n, u_int *l)
314{
315 struct xaddr tmp;
316 long unsigned int masklen = 999;
317 char addrbuf[64], *mp, *cp;
318
319 /* Don't modify argument */
Damien Miller97f43bb2012-06-30 08:32:29 +1000320 if (p == NULL || strlcpy(addrbuf, p, sizeof(addrbuf)) >= sizeof(addrbuf))
Darren Tucker7a3935d2008-06-10 22:59:10 +1000321 return -1;
322
323 if ((mp = strchr(addrbuf, '/')) != NULL) {
324 *mp = '\0';
325 mp++;
326 masklen = strtoul(mp, &cp, 10);
327 if (*mp == '\0' || *cp != '\0' || masklen > 128)
328 return -1;
329 }
330
331 if (addr_pton(addrbuf, &tmp) == -1)
332 return -1;
333
334 if (mp == NULL)
335 masklen = addr_unicast_masklen(tmp.af);
336 if (masklen_valid(tmp.af, masklen) == -1)
337 return -2;
338 if (addr_host_is_all0s(&tmp, masklen) != 0)
339 return -2;
340
341 if (n != NULL)
342 memcpy(n, &tmp, sizeof(*n));
343 if (l != NULL)
344 *l = masklen;
345
346 return 0;
347}
348
349static int
350addr_netmatch(const struct xaddr *host, const struct xaddr *net, u_int masklen)
351{
352 struct xaddr tmp_mask, tmp_result;
353
354 if (host->af != net->af)
355 return -1;
356
357 if (addr_netmask(host->af, masklen, &tmp_mask) == -1)
358 return -1;
359 if (addr_and(&tmp_result, host, &tmp_mask) == -1)
360 return -1;
361 return addr_cmp(&tmp_result, net);
362}
363
364/*
365 * Match "addr" against list pattern list "_list", which may contain a
366 * mix of CIDR addresses and old-school wildcards.
367 *
368 * If addr is NULL, then no matching is performed, but _list is parsed
369 * and checked for well-formedness.
370 *
371 * Returns 1 on match found (never returned when addr == NULL).
372 * Returns 0 on if no match found, or no errors found when addr == NULL.
Darren Tucker896ad5a2008-06-11 09:34:46 +1000373 * Returns -1 on negated match found (never returned when addr == NULL).
374 * Returns -2 on invalid list entry.
Darren Tucker7a3935d2008-06-10 22:59:10 +1000375 */
376int
377addr_match_list(const char *addr, const char *_list)
378{
379 char *list, *cp, *o;
380 struct xaddr try_addr, match_addr;
381 u_int masklen, neg;
382 int ret = 0, r;
383
384 if (addr != NULL && addr_pton(addr, &try_addr) != 0) {
385 debug2("%s: couldn't parse address %.100s", __func__, addr);
386 return 0;
387 }
388 if ((o = list = strdup(_list)) == NULL)
389 return -1;
390 while ((cp = strsep(&list, ",")) != NULL) {
391 neg = *cp == '!';
392 if (neg)
393 cp++;
394 if (*cp == '\0') {
Darren Tucker896ad5a2008-06-11 09:34:46 +1000395 ret = -2;
Darren Tucker7a3935d2008-06-10 22:59:10 +1000396 break;
397 }
398 /* Prefer CIDR address matching */
399 r = addr_pton_cidr(cp, &match_addr, &masklen);
400 if (r == -2) {
djm@openbsd.org23555eb2016-08-23 08:17:42 +0000401 debug2("%s: inconsistent mask length for "
402 "match network \"%.100s\"", __func__, cp);
Darren Tucker896ad5a2008-06-11 09:34:46 +1000403 ret = -2;
Darren Tucker7a3935d2008-06-10 22:59:10 +1000404 break;
405 } else if (r == 0) {
406 if (addr != NULL && addr_netmatch(&try_addr,
407 &match_addr, masklen) == 0) {
408 foundit:
409 if (neg) {
Darren Tucker896ad5a2008-06-11 09:34:46 +1000410 ret = -1;
Darren Tucker7a3935d2008-06-10 22:59:10 +1000411 break;
412 }
413 ret = 1;
djm@openbsd.orga5ad3a92016-09-21 16:55:42 +0000414 }
Darren Tucker7a3935d2008-06-10 22:59:10 +1000415 continue;
416 } else {
417 /* If CIDR parse failed, try wildcard string match */
418 if (addr != NULL && match_pattern(addr, cp) == 1)
419 goto foundit;
420 }
421 }
Darren Tuckera627d422013-06-02 07:31:17 +1000422 free(o);
Darren Tucker7a3935d2008-06-10 22:59:10 +1000423
424 return ret;
425}
Damien Miller0a80ca12010-02-27 07:55:05 +1100426
427/*
428 * Match "addr" against list CIDR list "_list". Lexical wildcards and
429 * negation are not supported. If "addr" == NULL, will verify structure
430 * of "_list".
431 *
432 * Returns 1 on match found (never returned when addr == NULL).
433 * Returns 0 on if no match found, or no errors found when addr == NULL.
434 * Returns -1 on error
435 */
436int
437addr_match_cidr_list(const char *addr, const char *_list)
438{
439 char *list, *cp, *o;
440 struct xaddr try_addr, match_addr;
441 u_int masklen;
442 int ret = 0, r;
443
444 if (addr != NULL && addr_pton(addr, &try_addr) != 0) {
445 debug2("%s: couldn't parse address %.100s", __func__, addr);
446 return 0;
447 }
448 if ((o = list = strdup(_list)) == NULL)
449 return -1;
450 while ((cp = strsep(&list, ",")) != NULL) {
451 if (*cp == '\0') {
452 error("%s: empty entry in list \"%.100s\"",
453 __func__, o);
454 ret = -1;
455 break;
456 }
457
458 /*
459 * NB. This function is called in pre-auth with untrusted data,
460 * so be extra paranoid about junk reaching getaddrino (via
461 * addr_pton_cidr).
462 */
463
464 /* Stop junk from reaching getaddrinfo. +3 is for masklen */
465 if (strlen(cp) > INET6_ADDRSTRLEN + 3) {
466 error("%s: list entry \"%.100s\" too long",
467 __func__, cp);
468 ret = -1;
469 break;
470 }
471#define VALID_CIDR_CHARS "0123456789abcdefABCDEF.:/"
472 if (strspn(cp, VALID_CIDR_CHARS) != strlen(cp)) {
473 error("%s: list entry \"%.100s\" contains invalid "
474 "characters", __func__, cp);
475 ret = -1;
476 }
477
478 /* Prefer CIDR address matching */
479 r = addr_pton_cidr(cp, &match_addr, &masklen);
480 if (r == -1) {
481 error("Invalid network entry \"%.100s\"", cp);
482 ret = -1;
483 break;
484 } else if (r == -2) {
485 error("Inconsistent mask length for "
486 "network \"%.100s\"", cp);
487 ret = -1;
488 break;
489 } else if (r == 0 && addr != NULL) {
490 if (addr_netmatch(&try_addr, &match_addr,
491 masklen) == 0)
492 ret = 1;
493 continue;
494 }
495 }
Darren Tuckera627d422013-06-02 07:31:17 +1000496 free(o);
Damien Miller0a80ca12010-02-27 07:55:05 +1100497
498 return ret;
499}