xref: /openbsd-src/usr.bin/ssh/addr.c (revision 632d59bf82ef1c5ae20fd4a1838ec4a541a50a00) 
1 /* $OpenBSD: addr.c,v 1.9 2024/10/18 04:30:09 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 #include <limits.h>
29 
30 #include "addr.h"
31 
32 #define _SA(x)	((struct sockaddr *)(x))
33 
34 static int
35 addr_unicast_masklen(int af)
36 {
37 	switch (af) {
38 	case AF_INET:
39 		return 32;
40 	case AF_INET6:
41 		return 128;
42 	default:
43 		return -1;
44 	}
45 }
46 
47 static inline int
48 masklen_valid(int af, u_int masklen)
49 {
50 	switch (af) {
51 	case AF_INET:
52 		return masklen <= 32 ? 0 : -1;
53 	case AF_INET6:
54 		return masklen <= 128 ? 0 : -1;
55 	default:
56 		return -1;
57 	}
58 }
59 
60 static int
61 addr_xaddr_to_sa(const struct xaddr *xa, struct sockaddr *sa, socklen_t *len,
62     u_int16_t port)
63 {
64 	struct sockaddr_in *in4 = (struct sockaddr_in *)sa;
65 	struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)sa;
66 
67 	if (xa == NULL || sa == NULL || len == NULL)
68 		return -1;
69 
70 	switch (xa->af) {
71 	case AF_INET:
72 		if (*len < sizeof(*in4))
73 			return -1;
74 		memset(sa, '\0', sizeof(*in4));
75 		*len = sizeof(*in4);
76 #ifdef SOCK_HAS_LEN
77 		in4->sin_len = sizeof(*in4);
78 #endif
79 		in4->sin_family = AF_INET;
80 		in4->sin_port = htons(port);
81 		memcpy(&in4->sin_addr, &xa->v4, sizeof(in4->sin_addr));
82 		break;
83 	case AF_INET6:
84 		if (*len < sizeof(*in6))
85 			return -1;
86 		memset(sa, '\0', sizeof(*in6));
87 		*len = sizeof(*in6);
88 #ifdef SOCK_HAS_LEN
89 		in6->sin6_len = sizeof(*in6);
90 #endif
91 		in6->sin6_family = AF_INET6;
92 		in6->sin6_port = htons(port);
93 		memcpy(&in6->sin6_addr, &xa->v6, sizeof(in6->sin6_addr));
94 		in6->sin6_scope_id = xa->scope_id;
95 		break;
96 	default:
97 		return -1;
98 	}
99 	return 0;
100 }
101 
102 /*
103  * Convert struct sockaddr to struct xaddr
104  * Returns 0 on success, -1 on failure.
105  */
106 int
107 addr_sa_to_xaddr(struct sockaddr *sa, socklen_t slen, struct xaddr *xa)
108 {
109 	struct sockaddr_in *in4 = (struct sockaddr_in *)sa;
110 	struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)sa;
111 
112 	memset(xa, '\0', sizeof(*xa));
113 
114 	switch (sa->sa_family) {
115 	case AF_INET:
116 		if (slen < (socklen_t)sizeof(*in4))
117 			return -1;
118 		xa->af = AF_INET;
119 		memcpy(&xa->v4, &in4->sin_addr, sizeof(xa->v4));
120 		break;
121 	case AF_INET6:
122 		if (slen < (socklen_t)sizeof(*in6))
123 			return -1;
124 		xa->af = AF_INET6;
125 		memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6));
126 #ifdef HAVE_STRUCT_SOCKADDR_IN6_SIN6_SCOPE_ID
127 		xa->scope_id = in6->sin6_scope_id;
128 #endif
129 		break;
130 	default:
131 		return -1;
132 	}
133 
134 	return 0;
135 }
136 
137 static int
138 addr_invert(struct xaddr *n)
139 {
140 	int i;
141 
142 	if (n == NULL)
143 		return -1;
144 
145 	switch (n->af) {
146 	case AF_INET:
147 		n->v4.s_addr = ~n->v4.s_addr;
148 		return 0;
149 	case AF_INET6:
150 		for (i = 0; i < 4; i++)
151 			n->addr32[i] = ~n->addr32[i];
152 		return 0;
153 	default:
154 		return -1;
155 	}
156 }
157 
158 /*
159  * Calculate a netmask of length 'l' for address family 'af' and
160  * store it in 'n'.
161  * Returns 0 on success, -1 on failure.
162  */
163 int
164 addr_netmask(int af, u_int l, struct xaddr *n)
165 {
166 	int i;
167 
168 	if (masklen_valid(af, l) != 0 || n == NULL)
169 		return -1;
170 
171 	memset(n, '\0', sizeof(*n));
172 	switch (af) {
173 	case AF_INET:
174 		n->af = AF_INET;
175 		if (l == 0)
176 			return 0;
177 		n->v4.s_addr = htonl((0xffffffff << (32 - l)) & 0xffffffff);
178 		return 0;
179 	case AF_INET6:
180 		n->af = AF_INET6;
181 		for (i = 0; i < 4 && l >= 32; i++, l -= 32)
182 			n->addr32[i] = 0xffffffffU;
183 		if (i < 4 && l != 0)
184 			n->addr32[i] = htonl((0xffffffff << (32 - l)) &
185 			    0xffffffff);
186 		return 0;
187 	default:
188 		return -1;
189 	}
190 }
191 
192 static int
193 addr_hostmask(int af, u_int l, struct xaddr *n)
194 {
195 	if (addr_netmask(af, l, n) == -1 || addr_invert(n) == -1)
196 		return -1;
197 	return 0;
198 }
199 
200 /*
201  * Perform logical AND of addresses 'a' and 'b', storing result in 'dst'.
202  * Returns 0 on success, -1 on failure.
203  */
204 int
205 addr_and(struct xaddr *dst, const struct xaddr *a, const struct xaddr *b)
206 {
207 	int i;
208 
209 	if (dst == NULL || a == NULL || b == NULL || a->af != b->af)
210 		return -1;
211 
212 	memcpy(dst, a, sizeof(*dst));
213 	switch (a->af) {
214 	case AF_INET:
215 		dst->v4.s_addr &= b->v4.s_addr;
216 		return 0;
217 	case AF_INET6:
218 		dst->scope_id = a->scope_id;
219 		for (i = 0; i < 4; i++)
220 			dst->addr32[i] &= b->addr32[i];
221 		return 0;
222 	default:
223 		return -1;
224 	}
225 }
226 
227 static int
228 addr_or(struct xaddr *dst, const struct xaddr *a, const struct xaddr *b)
229 {
230 	int i;
231 
232 	if (dst == NULL || a == NULL || b == NULL || a->af != b->af)
233 		return (-1);
234 
235 	memcpy(dst, a, sizeof(*dst));
236 	switch (a->af) {
237 	case AF_INET:
238 		dst->v4.s_addr |= b->v4.s_addr;
239 		return (0);
240 	case AF_INET6:
241 		for (i = 0; i < 4; i++)
242 			dst->addr32[i] |= b->addr32[i];
243 		return (0);
244 	default:
245 		return (-1);
246 	}
247 }
248 
249 int
250 addr_cmp(const struct xaddr *a, const struct xaddr *b)
251 {
252 	int i;
253 
254 	if (a->af != b->af)
255 		return (a->af == AF_INET6 ? 1 : -1);
256 
257 	switch (a->af) {
258 	case AF_INET:
259 		/*
260 		 * Can't just subtract here as 255.255.255.255 - 0.0.0.0 is
261 		 * too big to fit into a signed int
262 		 */
263 		if (a->v4.s_addr == b->v4.s_addr)
264 			return 0;
265 		return (ntohl(a->v4.s_addr) > ntohl(b->v4.s_addr) ? 1 : -1);
266 	case AF_INET6:
267 		/*
268 		 * Do this a byte at a time to avoid the above issue and
269 		 * any endian problems
270 		 */
271 		for (i = 0; i < 16; i++)
272 			if (a->addr8[i] - b->addr8[i] != 0)
273 				return (a->addr8[i] - b->addr8[i]);
274 		if (a->scope_id == b->scope_id)
275 			return (0);
276 		return (a->scope_id > b->scope_id ? 1 : -1);
277 	default:
278 		return (-1);
279 	}
280 }
281 
282 static int
283 addr_is_all0s(const struct xaddr *a)
284 {
285 	int i;
286 
287 	switch (a->af) {
288 	case AF_INET:
289 		return (a->v4.s_addr == 0 ? 0 : -1);
290 	case AF_INET6:
291 		for (i = 0; i < 4; i++)
292 			if (a->addr32[i] != 0)
293 				return -1;
294 		return 0;
295 	default:
296 		return -1;
297 	}
298 }
299 
300 /* Increment the specified address. Note, does not do overflow checking */
301 void
302 addr_increment(struct xaddr *a)
303 {
304 	int i;
305 	uint32_t n;
306 
307 	switch (a->af) {
308 	case AF_INET:
309 		a->v4.s_addr = htonl(ntohl(a->v4.s_addr) + 1);
310 		break;
311 	case AF_INET6:
312 		for (i = 0; i < 4; i++) {
313 			/* Increment with carry */
314 			n = ntohl(a->addr32[3 - i]) + 1;
315 			a->addr32[3 - i] = htonl(n);
316 			if (n != 0)
317 				break;
318 		}
319 		break;
320 	}
321 }
322 
323 /*
324  * Test whether host portion of address 'a', as determined by 'masklen'
325  * is all zeros.
326  * Returns 0 if host portion of address is all-zeros,
327  * -1 if not all zeros or on failure.
328  */
329 static int
330 addr_host_is_all0s(const struct xaddr *a, u_int masklen)
331 {
332 	struct xaddr tmp_addr, tmp_mask, tmp_result;
333 
334 	memcpy(&tmp_addr, a, sizeof(tmp_addr));
335 	if (addr_hostmask(a->af, masklen, &tmp_mask) == -1)
336 		return -1;
337 	if (addr_and(&tmp_result, &tmp_addr, &tmp_mask) == -1)
338 		return -1;
339 	return addr_is_all0s(&tmp_result);
340 }
341 
342 #if 0
343 static int
344 addr_host_to_all0s(struct xaddr *a, u_int masklen)
345 {
346 	struct xaddr tmp_mask;
347 
348 	if (addr_netmask(a->af, masklen, &tmp_mask) == -1)
349 		return (-1);
350 	if (addr_and(a, a, &tmp_mask) == -1)
351 		return (-1);
352 	return (0);
353 }
354 #endif
355 
356 int
357 addr_host_to_all1s(struct xaddr *a, u_int masklen)
358 {
359 	struct xaddr tmp_mask;
360 
361 	if (addr_hostmask(a->af, masklen, &tmp_mask) == -1)
362 		return (-1);
363 	if (addr_or(a, a, &tmp_mask) == -1)
364 		return (-1);
365 	return (0);
366 }
367 
368 /*
369  * Parse string address 'p' into 'n'.
370  * Returns 0 on success, -1 on failure.
371  */
372 int
373 addr_pton(const char *p, struct xaddr *n)
374 {
375 	struct addrinfo hints, *ai;
376 
377 	memset(&hints, '\0', sizeof(hints));
378 	hints.ai_flags = AI_NUMERICHOST;
379 
380 	if (p == NULL || getaddrinfo(p, NULL, &hints, &ai) != 0)
381 		return -1;
382 
383 	if (ai == NULL)
384 		return -1;
385 
386 	if (ai->ai_addr == NULL) {
387 		freeaddrinfo(ai);
388 		return -1;
389 	}
390 
391 	if (n != NULL && addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen,
392 	    n) == -1) {
393 		freeaddrinfo(ai);
394 		return -1;
395 	}
396 
397 	freeaddrinfo(ai);
398 	return 0;
399 }
400 
401 #if 0
402 static int
403 addr_sa_pton(const char *h, const char *s, struct sockaddr *sa, socklen_t slen)
404 {
405 	struct addrinfo hints, *ai;
406 
407 	memset(&hints, '\0', sizeof(hints));
408 	hints.ai_flags = AI_NUMERICHOST;
409 
410 	if (h == NULL || getaddrinfo(h, s, &hints, &ai) != 0)
411 		return -1;
412 
413 	if (ai == NULL)
414 		return -1;
415 
416 	if (ai->ai_addr == NULL) {
417 		freeaddrinfo(ai);
418 		return -1;
419 	}
420 
421 	if (sa != NULL) {
422 		if (slen < ai->ai_addrlen) {
423 			freeaddrinfo(ai);
424 			return -1;
425 		}
426 		memcpy(sa, &ai->ai_addr, ai->ai_addrlen);
427 	}
428 
429 	freeaddrinfo(ai);
430 	return 0;
431 }
432 #endif
433 
434 int
435 addr_ntop(const struct xaddr *n, char *p, size_t len)
436 {
437 	struct sockaddr_storage ss;
438 	socklen_t slen = sizeof(ss);
439 
440 	if (addr_xaddr_to_sa(n, _SA(&ss), &slen, 0) == -1)
441 		return -1;
442 	if (p == NULL || len == 0)
443 		return -1;
444 	if (getnameinfo(_SA(&ss), slen, p, len, NULL, 0,
445 	    NI_NUMERICHOST) != 0)
446 		return -1;
447 
448 	return 0;
449 }
450 
451 /*
452  * Parse a CIDR address (x.x.x.x/y or xxxx:yyyy::/z).
453  * Return -1 on parse error, -2 on inconsistency or 0 on success.
454  */
455 int
456 addr_pton_cidr(const char *p, struct xaddr *n, u_int *l)
457 {
458 	struct xaddr tmp;
459 	u_int masklen = 999;
460 	char addrbuf[64], *mp;
461 	const char *errstr;
462 
463 	/* Don't modify argument */
464 	if (p == NULL || strlcpy(addrbuf, p, sizeof(addrbuf)) >= sizeof(addrbuf))
465 		return -1;
466 
467 	if ((mp = strchr(addrbuf, '/')) != NULL) {
468 		*mp = '\0';
469 		mp++;
470 		masklen = (u_int)strtonum(mp, 0, INT_MAX, &errstr);
471 		if (errstr)
472 			return -1;
473 	}
474 
475 	if (addr_pton(addrbuf, &tmp) == -1)
476 		return -1;
477 
478 	if (mp == NULL)
479 		masklen = addr_unicast_masklen(tmp.af);
480 	if (masklen_valid(tmp.af, masklen) == -1)
481 		return -2;
482 	if (addr_host_is_all0s(&tmp, masklen) != 0)
483 		return -2;
484 
485 	if (n != NULL)
486 		memcpy(n, &tmp, sizeof(*n));
487 	if (l != NULL)
488 		*l = masklen;
489 
490 	return 0;
491 }
492 
493 int
494 addr_netmatch(const struct xaddr *host, const struct xaddr *net, u_int masklen)
495 {
496 	struct xaddr tmp_mask, tmp_result;
497 
498 	if (host->af != net->af)
499 		return -1;
500 
501 	if (addr_netmask(host->af, masklen, &tmp_mask) == -1)
502 		return -1;
503 	if (addr_and(&tmp_result, host, &tmp_mask) == -1)
504 		return -1;
505 	return addr_cmp(&tmp_result, net);
506 }
507