addrmatch.c revision 192595 
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
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 *)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 */
117static int
118addr_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 */
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;
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 */
232static int
233addr_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 */
258static int
259addr_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 */
270static int
271addr_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 */
294static int
295addr_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 */
311static int
312addr_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
348static int
349addr_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 */
375int
376addr_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}
425