1/* $NetBSD: addrmatch.c,v 1.13 2019/01/27 02:08:33 pgoyette Exp $ */
2/* $OpenBSD: addrmatch.c,v 1.14 2018/07/31 03:07:24 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
20#include "includes.h"
21__RCSID("$NetBSD: addrmatch.c,v 1.13 2019/01/27 02:08:33 pgoyette Exp $");
22#include <sys/types.h>
23#include <sys/socket.h>
24#include <netinet/in.h>
25#include <arpa/inet.h>
26
27#include <netdb.h>
28#include <string.h>
29#include <stdlib.h>
30#include <stdio.h>
31#include <stdarg.h>
32
33#include "match.h"
34#include "log.h"
35
36struct 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
51static int
52addr_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
64static inline int
65masklen_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 */
81static int
82addr_sa_to_xaddr(struct sockaddr *sa, socklen_t slen, struct xaddr *xa)
83{
84 struct sockaddr_in *in4 = (struct sockaddr_in *)(void *)sa;
85 struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)(void *)sa;
86
87 memset(xa, '\0', sizeof(*xa));
88
89 switch (sa->sa_family) {
90 case AF_INET:
91 if (slen < (socklen_t)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 < (socklen_t)sizeof(*in6))
98 return -1;
99 xa->af = AF_INET6;
100 memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6));
101 xa->scope_id = in6->sin6_scope_id;
102 break;
103 default:
104 return -1;
105 }
106
107 return 0;
108}
109
110/*
111 * Calculate a netmask of length 'l' for address family 'af' and
112 * store it in 'n'.
113 * Returns 0 on success, -1 on failure.
114 */
115static int
116addr_netmask(int af, u_int l, struct xaddr *n)
117{
118 int i;
119
120 if (masklen_valid(af, l) != 0 || n == NULL)
121 return -1;
122
123 memset(n, '\0', sizeof(*n));
124 switch (af) {
125 case AF_INET:
126 n->af = AF_INET;
127 if (l == 0)
128 return 0;
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 */
148static int
149addr_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 */
175static int
176addr_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 */
204static int
205addr_pton(const char *p, struct xaddr *n)
206{
207 struct addrinfo hints, *ai = NULL;
208 int ret = -1;
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 goto out;
215 if (ai == NULL || ai->ai_addr == NULL)
216 goto out;
217 if (n != NULL && addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen, n) == -1)
218 goto out;
219 /* success */
220 ret = 0;
221 out:
222 if (ai != NULL)
223 freeaddrinfo(ai);
224 return ret;
225}
226
227/*
228 * Perform bitwise negation of address
229 * Returns 0 on success, -1 on failure.
230 */
231static int
232addr_invert(struct xaddr *n)
233{
234 int i;
235
236 if (n == NULL)
237 return (-1);
238
239 switch (n->af) {
240 case AF_INET:
241 n->v4.s_addr = ~n->v4.s_addr;
242 return (0);
243 case AF_INET6:
244 for (i = 0; i < 4; i++)
245 n->addr32[i] = ~n->addr32[i];
246 return (0);
247 default:
248 return (-1);
249 }
250}
251
252/*
253 * Calculate a netmask of length 'l' for address family 'af' and
254 * store it in 'n'.
255 * Returns 0 on success, -1 on failure.
256 */
257static int
258addr_hostmask(int af, u_int l, struct xaddr *n)
259{
260 if (addr_netmask(af, l, n) == -1 || addr_invert(n) == -1)
261 return (-1);
262 return (0);
263}
264
265/*
266 * Test whether address 'a' is all zeros (i.e. 0.0.0.0 or ::)
267 * Returns 0 on if address is all-zeros, -1 if not all zeros or on failure.
268 */
269static int
270addr_is_all0s(const struct xaddr *a)
271{
272 int i;
273
274 switch (a->af) {
275 case AF_INET:
276 return (a->v4.s_addr == 0 ? 0 : -1);
277 case AF_INET6:;
278 for (i = 0; i < 4; i++)
279 if (a->addr32[i] != 0)
280 return (-1);
281 return (0);
282 default:
283 return (-1);
284 }
285}
286
287/*
288 * Test whether host portion of address 'a', as determined by 'masklen'
289 * is all zeros.
290 * Returns 0 on if host portion of address is all-zeros,
291 * -1 if not all zeros or on failure.
292 */
293static int
294addr_host_is_all0s(const struct xaddr *a, u_int masklen)
295{
296 struct xaddr tmp_addr, tmp_mask, tmp_result;
297
298 memcpy(&tmp_addr, a, sizeof(tmp_addr));
299 if (addr_hostmask(a->af, masklen, &tmp_mask) == -1)
300 return (-1);
301 if (addr_and(&tmp_result, &tmp_addr, &tmp_mask) == -1)
302 return (-1);
303 return (addr_is_all0s(&tmp_result));
304}
305
306/*
307 * Parse a CIDR address (x.x.x.x/y or xxxx:yyyy::/z).
308 * Return -1 on parse error, -2 on inconsistency or 0 on success.
309 */
310static int
311addr_pton_cidr(const char *p, struct xaddr *n, u_int *l)
312{
313 struct xaddr tmp;
314 unsigned int masklen = 999;
315 char addrbuf[64], *mp, *cp;
316
317 /* Don't modify argument */
318 if (p == NULL || strlcpy(addrbuf, p, sizeof(addrbuf)) >= sizeof(addrbuf))
319 return -1;
320
321 if ((mp = strchr(addrbuf, '/')) != NULL) {
322 *mp = '\0';
323 mp++;
324 masklen = strtoul(mp, &cp, 10);
325 if (*mp == '\0' || *cp != '\0' || masklen > 128)
326 return -1;
327 }
328
329 if (addr_pton(addrbuf, &tmp) == -1)
330 return -1;
331
332 if (mp == NULL)
333 masklen = addr_unicast_masklen(tmp.af);
334 if (masklen_valid(tmp.af, masklen) == -1)
335 return -2;
336 if (addr_host_is_all0s(&tmp, masklen) != 0)
337 return -2;
338
339 if (n != NULL)
340 memcpy(n, &tmp, sizeof(*n));
341 if (l != NULL)
342 *l = masklen;
343
344 return 0;
345}
346
347static int
348addr_netmatch(const struct xaddr *host, const struct xaddr *net, u_int masklen)
349{
350 struct xaddr tmp_mask, tmp_result;
351
352 if (host->af != net->af)
353 return -1;
354
355 if (addr_netmask(host->af, masklen, &tmp_mask) == -1)
356 return -1;
357 if (addr_and(&tmp_result, host, &tmp_mask) == -1)
358 return -1;
359 return addr_cmp(&tmp_result, net);
360}
361
362/*
363 * Match "addr" against list pattern list "_list", which may contain a
364 * mix of CIDR addresses and old-school wildcards.
365 *
366 * If addr is NULL, then no matching is performed, but _list is parsed
367 * and checked for well-formedness.
368 *
369 * Returns 1 on match found (never returned when addr == NULL).
370 * Returns 0 on if no match found, or no errors found when addr == NULL.
371 * Returns -1 on negated match found (never returned when addr == NULL).
372 * Returns -2 on invalid list entry.
373 */
374int
375addr_match_list(const char *addr, const char *_list)
376{
377 char *list, *cp, *o;
378 struct xaddr try_addr, match_addr;
379 u_int masklen, neg;
380 int ret = 0, r;
381
382 if (addr != NULL && addr_pton(addr, &try_addr) != 0) {
383 debug2("%s: couldn't parse address %.100s", __func__, addr);
384 return 0;
385 }
386 if ((o = list = strdup(_list)) == NULL)
387 return -1;
388 while ((cp = strsep(&list, ",")) != NULL) {
389 neg = *cp == '!';
390 if (neg)
391 cp++;
392 if (*cp == '\0') {
393 ret = -2;
394 break;
395 }
396 /* Prefer CIDR address matching */
397 r = addr_pton_cidr(cp, &match_addr, &masklen);
398 if (r == -2) {
399 debug2("%s: inconsistent mask length for "
400 "match network \"%.100s\"", __func__, cp);
401 ret = -2;
402 break;
403 } else if (r == 0) {
404 if (addr != NULL && addr_netmatch(&try_addr,
405 &match_addr, masklen) == 0) {
406 foundit:
407 if (neg) {
408 ret = -1;
409 break;
410 }
411 ret = 1;
412 }
413 continue;
414 } else {
415 /* If CIDR parse failed, try wildcard string match */
416 if (addr != NULL && match_pattern(addr, cp) == 1)
417 goto foundit;
418 }
419 }
420 free(o);
421
422 return ret;
423}
424
425/*
426 * Match "addr" against list CIDR list "_list". Lexical wildcards and
427 * negation are not supported. If "addr" == NULL, will verify structure
428 * of "_list".
429 *
430 * Returns 1 on match found (never returned when addr == NULL).
431 * Returns 0 on if no match found, or no errors found when addr == NULL.
432 * Returns -1 on error
433 */
434int
435addr_match_cidr_list(const char *addr, const char *_list)
436{
437 char *list, *cp, *o;
438 struct xaddr try_addr, match_addr;
439 u_int masklen;
440 int ret = 0, r;
441
442 if (addr != NULL && addr_pton(addr, &try_addr) != 0) {
443 debug2("%s: couldn't parse address %.100s", __func__, addr);
444 return 0;
445 }
446 if ((o = list = strdup(_list)) == NULL)
447 return -1;
448 while ((cp = strsep(&list, ",")) != NULL) {
449 if (*cp == '\0') {
450 error("%s: empty entry in list \"%.100s\"",
451 __func__, o);
452 ret = -1;
453 break;
454 }
455
456 /*
457 * NB. This function is called in pre-auth with untrusted data,
458 * so be extra paranoid about junk reaching getaddrino (via
459 * addr_pton_cidr).
460 */
461
462 /* Stop junk from reaching getaddrinfo. +3 is for masklen */
463 if (strlen(cp) > INET6_ADDRSTRLEN + 3) {
464 error("%s: list entry \"%.100s\" too long",
465 __func__, cp);
466 ret = -1;
467 break;
468 }
469#define VALID_CIDR_CHARS "0123456789abcdefABCDEF.:/"
470 if (strspn(cp, VALID_CIDR_CHARS) != strlen(cp)) {
471 error("%s: list entry \"%.100s\" contains invalid "
472 "characters", __func__, cp);
473 ret = -1;
474 }
475
476 /* Prefer CIDR address matching */
477 r = addr_pton_cidr(cp, &match_addr, &masklen);
478 if (r == -1) {
479 error("Invalid network entry \"%.100s\"", cp);
480 ret = -1;
481 break;
482 } else if (r == -2) {
483 error("Inconsistent mask length for "
484 "network \"%.100s\"", cp);
485 ret = -1;
486 break;
487 } else if (r == 0 && addr != NULL) {
488 if (addr_netmatch(&try_addr, &match_addr,
489 masklen) == 0)
490 ret = 1;
491 continue;
492 }
493 }
494 free(o);
495
496 return ret;
497}
498