xref: /dragonfly/crypto/openssh/addrmatch.c (revision dcd37f7d) 
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 	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  */
117 static int
118 addr_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  */
148 static int
149 addr_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  */
175 static int
176 addr_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  */
204 static int
205 addr_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  */
232 static int
233 addr_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  */
258 static int
259 addr_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  */
270 static int
271 addr_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  */
294 static int
295 addr_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  */
311 static int
312 addr_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 
348 static int
349 addr_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  */
375 int
376 addr_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