xref: /openbsd-src/usr.bin/ssh/addr.c (revision 3374c67d44f9b75b98444cbf63020f777792342e) 
1 /* $OpenBSD: addr.c,v 1.6 2022/10/28 02:29:34 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 <sys/types.h>
20 #include <sys/socket.h>
21 #include <netinet/in.h>
22 #include <arpa/inet.h>
23 
24 #include <netdb.h>
25 #include <string.h>
26 #include <stdlib.h>
27 #include <stdio.h>
28 
29 #include "addr.h"
30 
31 #define _SA(x)	((struct sockaddr *)(x))
32 
33 int
34 addr_unicast_masklen(int af)
35 {
36 	switch (af) {
37 	case AF_INET:
38 		return 32;
39 	case AF_INET6:
40 		return 128;
41 	default:
42 		return -1;
43 	}
44 }
45 
46 static inline int
47 masklen_valid(int af, u_int masklen)
48 {
49 	switch (af) {
50 	case AF_INET:
51 		return masklen <= 32 ? 0 : -1;
52 	case AF_INET6:
53 		return masklen <= 128 ? 0 : -1;
54 	default:
55 		return -1;
56 	}
57 }
58 
59 int
60 addr_xaddr_to_sa(const struct xaddr *xa, struct sockaddr *sa, socklen_t *len,
61     u_int16_t port)
62 {
63 	struct sockaddr_in *in4 = (struct sockaddr_in *)sa;
64 	struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)sa;
65 
66 	if (xa == NULL || sa == NULL || len == NULL)
67 		return -1;
68 
69 	switch (xa->af) {
70 	case AF_INET:
71 		if (*len < sizeof(*in4))
72 			return -1;
73 		memset(sa, '\0', sizeof(*in4));
74 		*len = sizeof(*in4);
75 #ifdef SOCK_HAS_LEN
76 		in4->sin_len = sizeof(*in4);
77 #endif
78 		in4->sin_family = AF_INET;
79 		in4->sin_port = htons(port);
80 		memcpy(&in4->sin_addr, &xa->v4, sizeof(in4->sin_addr));
81 		break;
82 	case AF_INET6:
83 		if (*len < sizeof(*in6))
84 			return -1;
85 		memset(sa, '\0', sizeof(*in6));
86 		*len = sizeof(*in6);
87 #ifdef SOCK_HAS_LEN
88 		in6->sin6_len = sizeof(*in6);
89 #endif
90 		in6->sin6_family = AF_INET6;
91 		in6->sin6_port = htons(port);
92 		memcpy(&in6->sin6_addr, &xa->v6, sizeof(in6->sin6_addr));
93 		in6->sin6_scope_id = xa->scope_id;
94 		break;
95 	default:
96 		return -1;
97 	}
98 	return 0;
99 }
100 
101 /*
102  * Convert struct sockaddr to struct xaddr
103  * Returns 0 on success, -1 on failure.
104  */
105 int
106 addr_sa_to_xaddr(struct sockaddr *sa, socklen_t slen, struct xaddr *xa)
107 {
108 	struct sockaddr_in *in4 = (struct sockaddr_in *)sa;
109 	struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)sa;
110 
111 	memset(xa, '\0', sizeof(*xa));
112 
113 	switch (sa->sa_family) {
114 	case AF_INET:
115 		if (slen < (socklen_t)sizeof(*in4))
116 			return -1;
117 		xa->af = AF_INET;
118 		memcpy(&xa->v4, &in4->sin_addr, sizeof(xa->v4));
119 		break;
120 	case AF_INET6:
121 		if (slen < (socklen_t)sizeof(*in6))
122 			return -1;
123 		xa->af = AF_INET6;
124 		memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6));
125 #ifdef HAVE_STRUCT_SOCKADDR_IN6_SIN6_SCOPE_ID
126 		xa->scope_id = in6->sin6_scope_id;
127 #endif
128 		break;
129 	default:
130 		return -1;
131 	}
132 
133 	return 0;
134 }
135 
136 int
137 addr_invert(struct xaddr *n)
138 {
139 	int i;
140 
141 	if (n == NULL)
142 		return -1;
143 
144 	switch (n->af) {
145 	case AF_INET:
146 		n->v4.s_addr = ~n->v4.s_addr;
147 		return 0;
148 	case AF_INET6:
149 		for (i = 0; i < 4; i++)
150 			n->addr32[i] = ~n->addr32[i];
151 		return 0;
152 	default:
153 		return -1;
154 	}
155 }
156 
157 /*
158  * Calculate a netmask of length 'l' for address family 'af' and
159  * store it in 'n'.
160  * Returns 0 on success, -1 on failure.
161  */
162 int
163 addr_netmask(int af, u_int l, struct xaddr *n)
164 {
165 	int i;
166 
167 	if (masklen_valid(af, l) != 0 || n == NULL)
168 		return -1;
169 
170 	memset(n, '\0', sizeof(*n));
171 	switch (af) {
172 	case AF_INET:
173 		n->af = AF_INET;
174 		if (l == 0)
175 			return 0;
176 		n->v4.s_addr = htonl((0xffffffff << (32 - l)) & 0xffffffff);
177 		return 0;
178 	case AF_INET6:
179 		n->af = AF_INET6;
180 		for (i = 0; i < 4 && l >= 32; i++, l -= 32)
181 			n->addr32[i] = 0xffffffffU;
182 		if (i < 4 && l != 0)
183 			n->addr32[i] = htonl((0xffffffff << (32 - l)) &
184 			    0xffffffff);
185 		return 0;
186 	default:
187 		return -1;
188 	}
189 }
190 
191 int
192 addr_hostmask(int af, u_int l, struct xaddr *n)
193 {
194 	if (addr_netmask(af, l, n) == -1 || addr_invert(n) == -1)
195 		return -1;
196 	return 0;
197 }
198 
199 /*
200  * Perform logical AND of addresses 'a' and 'b', storing result in 'dst'.
201  * Returns 0 on success, -1 on failure.
202  */
203 int
204 addr_and(struct xaddr *dst, const struct xaddr *a, const struct xaddr *b)
205 {
206 	int i;
207 
208 	if (dst == NULL || a == NULL || b == NULL || a->af != b->af)
209 		return -1;
210 
211 	memcpy(dst, a, sizeof(*dst));
212 	switch (a->af) {
213 	case AF_INET:
214 		dst->v4.s_addr &= b->v4.s_addr;
215 		return 0;
216 	case AF_INET6:
217 		dst->scope_id = a->scope_id;
218 		for (i = 0; i < 4; i++)
219 			dst->addr32[i] &= b->addr32[i];
220 		return 0;
221 	default:
222 		return -1;
223 	}
224 }
225 
226 int
227 addr_or(struct xaddr *dst, const struct xaddr *a, const struct xaddr *b)
228 {
229 	int i;
230 
231 	if (dst == NULL || a == NULL || b == NULL || a->af != b->af)
232 		return (-1);
233 
234 	memcpy(dst, a, sizeof(*dst));
235 	switch (a->af) {
236 	case AF_INET:
237 		dst->v4.s_addr |= b->v4.s_addr;
238 		return (0);
239 	case AF_INET6:
240 		for (i = 0; i < 4; i++)
241 			dst->addr32[i] |= b->addr32[i];
242 		return (0);
243 	default:
244 		return (-1);
245 	}
246 }
247 
248 int
249 addr_cmp(const struct xaddr *a, const struct xaddr *b)
250 {
251 	int i;
252 
253 	if (a->af != b->af)
254 		return (a->af == AF_INET6 ? 1 : -1);
255 
256 	switch (a->af) {
257 	case AF_INET:
258 		/*
259 		 * Can't just subtract here as 255.255.255.255 - 0.0.0.0 is
260 		 * too big to fit into a signed int
261 		 */
262 		if (a->v4.s_addr == b->v4.s_addr)
263 			return 0;
264 		return (ntohl(a->v4.s_addr) > ntohl(b->v4.s_addr) ? 1 : -1);
265 	case AF_INET6:
266 		/*
267 		 * Do this a byte at a time to avoid the above issue and
268 		 * any endian problems
269 		 */
270 		for (i = 0; i < 16; i++)
271 			if (a->addr8[i] - b->addr8[i] != 0)
272 				return (a->addr8[i] - b->addr8[i]);
273 		if (a->scope_id == b->scope_id)
274 			return (0);
275 		return (a->scope_id > b->scope_id ? 1 : -1);
276 	default:
277 		return (-1);
278 	}
279 }
280 
281 int
282 addr_is_all0s(const struct xaddr *a)
283 {
284 	int i;
285 
286 	switch (a->af) {
287 	case AF_INET:
288 		return (a->v4.s_addr == 0 ? 0 : -1);
289 	case AF_INET6:
290 		for (i = 0; i < 4; i++)
291 			if (a->addr32[i] != 0)
292 				return -1;
293 		return 0;
294 	default:
295 		return -1;
296 	}
297 }
298 
299 /* Increment the specified address. Note, does not do overflow checking */
300 void
301 addr_increment(struct xaddr *a)
302 {
303 	int i;
304 	uint32_t n;
305 
306 	switch (a->af) {
307 	case AF_INET:
308 		a->v4.s_addr = htonl(ntohl(a->v4.s_addr) + 1);
309 		break;
310 	case AF_INET6:
311 		for (i = 0; i < 4; i++) {
312 			/* Increment with carry */
313 			n = ntohl(a->addr32[3 - i]) + 1;
314 			a->addr32[3 - i] = htonl(n);
315 			if (n != 0)
316 				break;
317 		}
318 		break;
319 	}
320 }
321 
322 /*
323  * Test whether host portion of address 'a', as determined by 'masklen'
324  * is all zeros.
325  * Returns 0 if host portion of address is all-zeros,
326  * -1 if not all zeros or on failure.
327  */
328 int
329 addr_host_is_all0s(const struct xaddr *a, u_int masklen)
330 {
331 	struct xaddr tmp_addr, tmp_mask, tmp_result;
332 
333 	memcpy(&tmp_addr, a, sizeof(tmp_addr));
334 	if (addr_hostmask(a->af, masklen, &tmp_mask) == -1)
335 		return -1;
336 	if (addr_and(&tmp_result, &tmp_addr, &tmp_mask) == -1)
337 		return -1;
338 	return addr_is_all0s(&tmp_result);
339 }
340 
341 #if 0
342 int
343 addr_host_to_all0s(struct xaddr *a, u_int masklen)
344 {
345 	struct xaddr tmp_mask;
346 
347 	if (addr_netmask(a->af, masklen, &tmp_mask) == -1)
348 		return (-1);
349 	if (addr_and(a, a, &tmp_mask) == -1)
350 		return (-1);
351 	return (0);
352 }
353 #endif
354 
355 int
356 addr_host_to_all1s(struct xaddr *a, u_int masklen)
357 {
358 	struct xaddr tmp_mask;
359 
360 	if (addr_hostmask(a->af, masklen, &tmp_mask) == -1)
361 		return (-1);
362 	if (addr_or(a, a, &tmp_mask) == -1)
363 		return (-1);
364 	return (0);
365 }
366 
367 /*
368  * Parse string address 'p' into 'n'.
369  * Returns 0 on success, -1 on failure.
370  */
371 int
372 addr_pton(const char *p, struct xaddr *n)
373 {
374 	struct addrinfo hints, *ai;
375 
376 	memset(&hints, '\0', sizeof(hints));
377 	hints.ai_flags = AI_NUMERICHOST;
378 
379 	if (p == NULL || getaddrinfo(p, NULL, &hints, &ai) != 0)
380 		return -1;
381 
382 	if (ai == NULL)
383 		return -1;
384 
385 	if (ai->ai_addr == NULL) {
386 		freeaddrinfo(ai);
387 		return -1;
388 	}
389 
390 	if (n != NULL && addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen,
391 	    n) == -1) {
392 		freeaddrinfo(ai);
393 		return -1;
394 	}
395 
396 	freeaddrinfo(ai);
397 	return 0;
398 }
399 
400 int
401 addr_sa_pton(const char *h, const char *s, struct sockaddr *sa, socklen_t slen)
402 {
403 	struct addrinfo hints, *ai;
404 
405 	memset(&hints, '\0', sizeof(hints));
406 	hints.ai_flags = AI_NUMERICHOST;
407 
408 	if (h == NULL || getaddrinfo(h, s, &hints, &ai) != 0)
409 		return -1;
410 
411 	if (ai == NULL)
412 		return -1;
413 
414 	if (ai->ai_addr == NULL) {
415 		freeaddrinfo(ai);
416 		return -1;
417 	}
418 
419 	if (sa != NULL) {
420 		if (slen < ai->ai_addrlen) {
421 			freeaddrinfo(ai);
422 			return -1;
423 		}
424 		memcpy(sa, &ai->ai_addr, ai->ai_addrlen);
425 	}
426 
427 	freeaddrinfo(ai);
428 	return 0;
429 }
430 
431 int
432 addr_ntop(const struct xaddr *n, char *p, size_t len)
433 {
434 	struct sockaddr_storage ss;
435 	socklen_t slen = sizeof(ss);
436 
437 	if (addr_xaddr_to_sa(n, _SA(&ss), &slen, 0) == -1)
438 		return -1;
439 	if (p == NULL || len == 0)
440 		return -1;
441 	if (getnameinfo(_SA(&ss), slen, p, len, NULL, 0,
442 	    NI_NUMERICHOST) == -1)
443 		return -1;
444 
445 	return 0;
446 }
447 
448 /*
449  * Parse a CIDR address (x.x.x.x/y or xxxx:yyyy::/z).
450  * Return -1 on parse error, -2 on inconsistency or 0 on success.
451  */
452 int
453 addr_pton_cidr(const char *p, struct xaddr *n, u_int *l)
454 {
455 	struct xaddr tmp;
456 	long unsigned int masklen = 999;
457 	char addrbuf[64], *mp, *cp;
458 
459 	/* Don't modify argument */
460 	if (p == NULL || strlcpy(addrbuf, p, sizeof(addrbuf)) >= sizeof(addrbuf))
461 		return -1;
462 
463 	if ((mp = strchr(addrbuf, '/')) != NULL) {
464 		*mp = '\0';
465 		mp++;
466 		masklen = strtoul(mp, &cp, 10);
467 		if (*mp < '0' || *mp > '9' || *cp != '\0' || masklen > 128)
468 			return -1;
469 	}
470 
471 	if (addr_pton(addrbuf, &tmp) == -1)
472 		return -1;
473 
474 	if (mp == NULL)
475 		masklen = addr_unicast_masklen(tmp.af);
476 	if (masklen_valid(tmp.af, masklen) == -1)
477 		return -2;
478 	if (addr_host_is_all0s(&tmp, masklen) != 0)
479 		return -2;
480 
481 	if (n != NULL)
482 		memcpy(n, &tmp, sizeof(*n));
483 	if (l != NULL)
484 		*l = masklen;
485 
486 	return 0;
487 }
488 
489 int
490 addr_netmatch(const struct xaddr *host, const struct xaddr *net, u_int masklen)
491 {
492 	struct xaddr tmp_mask, tmp_result;
493 
494 	if (host->af != net->af)
495 		return -1;
496 
497 	if (addr_netmask(host->af, masklen, &tmp_mask) == -1)
498 		return -1;
499 	if (addr_and(&tmp_result, host, &tmp_mask) == -1)
500 		return -1;
501 	return addr_cmp(&tmp_result, net);
502 }
503