xref: /openssh-portable/addr.c (revision 95eca1e1)
1 /* $OpenBSD: addr.c,v 1.1 2021/01/09 11:58:50 dtucker 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 
31 #include "addr.h"
32 
33 #define _SA(x)	((struct sockaddr *)(x))
34 
35 int
addr_unicast_masklen(int af)36 addr_unicast_masklen(int af)
37 {
38 	switch (af) {
39 	case AF_INET:
40 		return 32;
41 	case AF_INET6:
42 		return 128;
43 	default:
44 		return -1;
45 	}
46 }
47 
48 static inline int
masklen_valid(int af,u_int masklen)49 masklen_valid(int af, u_int masklen)
50 {
51 	switch (af) {
52 	case AF_INET:
53 		return masklen <= 32 ? 0 : -1;
54 	case AF_INET6:
55 		return masklen <= 128 ? 0 : -1;
56 	default:
57 		return -1;
58 	}
59 }
60 
61 int
addr_xaddr_to_sa(const struct xaddr * xa,struct sockaddr * sa,socklen_t * len,u_int16_t port)62 addr_xaddr_to_sa(const struct xaddr *xa, struct sockaddr *sa, socklen_t *len,
63     u_int16_t port)
64 {
65 	struct sockaddr_in *in4 = (struct sockaddr_in *)sa;
66 	struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)sa;
67 
68 	if (xa == NULL || sa == NULL || len == NULL)
69 		return -1;
70 
71 	switch (xa->af) {
72 	case AF_INET:
73 		if (*len < sizeof(*in4))
74 			return -1;
75 		memset(sa, '\0', sizeof(*in4));
76 		*len = sizeof(*in4);
77 #ifdef SOCK_HAS_LEN
78 		in4->sin_len = sizeof(*in4);
79 #endif
80 		in4->sin_family = AF_INET;
81 		in4->sin_port = htons(port);
82 		memcpy(&in4->sin_addr, &xa->v4, sizeof(in4->sin_addr));
83 		break;
84 	case AF_INET6:
85 		if (*len < sizeof(*in6))
86 			return -1;
87 		memset(sa, '\0', sizeof(*in6));
88 		*len = sizeof(*in6);
89 #ifdef SOCK_HAS_LEN
90 		in6->sin6_len = sizeof(*in6);
91 #endif
92 		in6->sin6_family = AF_INET6;
93 		in6->sin6_port = htons(port);
94 		memcpy(&in6->sin6_addr, &xa->v6, sizeof(in6->sin6_addr));
95 #ifdef HAVE_STRUCT_SOCKADDR_IN6_SIN6_SCOPE_ID
96 		in6->sin6_scope_id = xa->scope_id;
97 #endif
98 		break;
99 	default:
100 		return -1;
101 	}
102 	return 0;
103 }
104 
105 /*
106  * Convert struct sockaddr to struct xaddr
107  * Returns 0 on success, -1 on failure.
108  */
109 int
addr_sa_to_xaddr(struct sockaddr * sa,socklen_t slen,struct xaddr * xa)110 addr_sa_to_xaddr(struct sockaddr *sa, socklen_t slen, struct xaddr *xa)
111 {
112 	struct sockaddr_in *in4 = (struct sockaddr_in *)sa;
113 	struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)sa;
114 
115 	memset(xa, '\0', sizeof(*xa));
116 
117 	switch (sa->sa_family) {
118 	case AF_INET:
119 		if (slen < (socklen_t)sizeof(*in4))
120 			return -1;
121 		xa->af = AF_INET;
122 		memcpy(&xa->v4, &in4->sin_addr, sizeof(xa->v4));
123 		break;
124 	case AF_INET6:
125 		if (slen < (socklen_t)sizeof(*in6))
126 			return -1;
127 		xa->af = AF_INET6;
128 		memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6));
129 #ifdef HAVE_STRUCT_SOCKADDR_IN6_SIN6_SCOPE_ID
130 		xa->scope_id = in6->sin6_scope_id;
131 #endif
132 		break;
133 	default:
134 		return -1;
135 	}
136 
137 	return 0;
138 }
139 
140 int
addr_invert(struct xaddr * n)141 addr_invert(struct xaddr *n)
142 {
143 	int i;
144 
145 	if (n == NULL)
146 		return -1;
147 
148 	switch (n->af) {
149 	case AF_INET:
150 		n->v4.s_addr = ~n->v4.s_addr;
151 		return 0;
152 	case AF_INET6:
153 		for (i = 0; i < 4; i++)
154 			n->addr32[i] = ~n->addr32[i];
155 		return 0;
156 	default:
157 		return -1;
158 	}
159 }
160 
161 /*
162  * Calculate a netmask of length 'l' for address family 'af' and
163  * store it in 'n'.
164  * Returns 0 on success, -1 on failure.
165  */
166 int
addr_netmask(int af,u_int l,struct xaddr * n)167 addr_netmask(int af, u_int l, struct xaddr *n)
168 {
169 	int i;
170 
171 	if (masklen_valid(af, l) != 0 || n == NULL)
172 		return -1;
173 
174 	memset(n, '\0', sizeof(*n));
175 	switch (af) {
176 	case AF_INET:
177 		n->af = AF_INET;
178 		if (l == 0)
179 			return 0;
180 		n->v4.s_addr = htonl((0xffffffff << (32 - l)) & 0xffffffff);
181 		return 0;
182 	case AF_INET6:
183 		n->af = AF_INET6;
184 		for (i = 0; i < 4 && l >= 32; i++, l -= 32)
185 			n->addr32[i] = 0xffffffffU;
186 		if (i < 4 && l != 0)
187 			n->addr32[i] = htonl((0xffffffff << (32 - l)) &
188 			    0xffffffff);
189 		return 0;
190 	default:
191 		return -1;
192 	}
193 }
194 
195 int
addr_hostmask(int af,u_int l,struct xaddr * n)196 addr_hostmask(int af, u_int l, struct xaddr *n)
197 {
198 	if (addr_netmask(af, l, n) == -1 || addr_invert(n) == -1)
199 		return -1;
200 	return 0;
201 }
202 
203 /*
204  * Perform logical AND of addresses 'a' and 'b', storing result in 'dst'.
205  * Returns 0 on success, -1 on failure.
206  */
207 int
addr_and(struct xaddr * dst,const struct xaddr * a,const struct xaddr * b)208 addr_and(struct xaddr *dst, const struct xaddr *a, const struct xaddr *b)
209 {
210 	int i;
211 
212 	if (dst == NULL || a == NULL || b == NULL || a->af != b->af)
213 		return -1;
214 
215 	memcpy(dst, a, sizeof(*dst));
216 	switch (a->af) {
217 	case AF_INET:
218 		dst->v4.s_addr &= b->v4.s_addr;
219 		return 0;
220 	case AF_INET6:
221 		dst->scope_id = a->scope_id;
222 		for (i = 0; i < 4; i++)
223 			dst->addr32[i] &= b->addr32[i];
224 		return 0;
225 	default:
226 		return -1;
227 	}
228 }
229 
230 int
addr_cmp(const struct xaddr * a,const struct xaddr * b)231 addr_cmp(const struct xaddr *a, const struct xaddr *b)
232 {
233 	int i;
234 
235 	if (a->af != b->af)
236 		return (a->af == AF_INET6 ? 1 : -1);
237 
238 	switch (a->af) {
239 	case AF_INET:
240 		/*
241 		 * Can't just subtract here as 255.255.255.255 - 0.0.0.0 is
242 		 * too big to fit into a signed int
243 		 */
244 		if (a->v4.s_addr == b->v4.s_addr)
245 			return 0;
246 		return (ntohl(a->v4.s_addr) > ntohl(b->v4.s_addr) ? 1 : -1);
247 	case AF_INET6:;
248 		/*
249 		 * Do this a byte at a time to avoid the above issue and
250 		 * any endian problems
251 		 */
252 		for (i = 0; i < 16; i++)
253 			if (a->addr8[i] - b->addr8[i] != 0)
254 				return (a->addr8[i] - b->addr8[i]);
255 		if (a->scope_id == b->scope_id)
256 			return (0);
257 		return (a->scope_id > b->scope_id ? 1 : -1);
258 	default:
259 		return (-1);
260 	}
261 }
262 
263 int
addr_is_all0s(const struct xaddr * a)264 addr_is_all0s(const struct xaddr *a)
265 {
266 	int i;
267 
268 	switch (a->af) {
269 	case AF_INET:
270 		return (a->v4.s_addr == 0 ? 0 : -1);
271 	case AF_INET6:;
272 		for (i = 0; i < 4; i++)
273 			if (a->addr32[i] != 0)
274 				return -1;
275 		return 0;
276 	default:
277 		return -1;
278 	}
279 }
280 
281 /*
282  * Test whether host portion of address 'a', as determined by 'masklen'
283  * is all zeros.
284  * Returns 0 on if host portion of address is all-zeros,
285  * -1 if not all zeros or on failure.
286  */
287 int
addr_host_is_all0s(const struct xaddr * a,u_int masklen)288 addr_host_is_all0s(const struct xaddr *a, u_int masklen)
289 {
290 	struct xaddr tmp_addr, tmp_mask, tmp_result;
291 
292 	memcpy(&tmp_addr, a, sizeof(tmp_addr));
293 	if (addr_hostmask(a->af, masklen, &tmp_mask) == -1)
294 		return -1;
295 	if (addr_and(&tmp_result, &tmp_addr, &tmp_mask) == -1)
296 		return -1;
297 	return addr_is_all0s(&tmp_result);
298 }
299 
300 /*
301  * Parse string address 'p' into 'n'
302  * Returns 0 on success, -1 on failure.
303  */
304 int
addr_pton(const char * p,struct xaddr * n)305 addr_pton(const char *p, struct xaddr *n)
306 {
307 	struct addrinfo hints, *ai;
308 
309 	memset(&hints, '\0', sizeof(hints));
310 	hints.ai_flags = AI_NUMERICHOST;
311 
312 	if (p == NULL || getaddrinfo(p, NULL, &hints, &ai) != 0)
313 		return -1;
314 
315 	if (ai == NULL || ai->ai_addr == NULL)
316 		return -1;
317 
318 	if (n != NULL && addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen,
319 	    n) == -1) {
320 		freeaddrinfo(ai);
321 		return -1;
322 	}
323 
324 	freeaddrinfo(ai);
325 	return 0;
326 }
327 
328 int
addr_sa_pton(const char * h,const char * s,struct sockaddr * sa,socklen_t slen)329 addr_sa_pton(const char *h, const char *s, struct sockaddr *sa, socklen_t slen)
330 {
331 	struct addrinfo hints, *ai;
332 
333 	memset(&hints, '\0', sizeof(hints));
334 	hints.ai_flags = AI_NUMERICHOST;
335 
336 	if (h == NULL || getaddrinfo(h, s, &hints, &ai) != 0)
337 		return -1;
338 
339 	if (ai == NULL || ai->ai_addr == NULL)
340 		return -1;
341 
342 	if (sa != NULL) {
343 		if (slen < ai->ai_addrlen)
344 			return -1;
345 		memcpy(sa, &ai->ai_addr, ai->ai_addrlen);
346 	}
347 
348 	freeaddrinfo(ai);
349 	return 0;
350 }
351 
352 int
addr_ntop(const struct xaddr * n,char * p,size_t len)353 addr_ntop(const struct xaddr *n, char *p, size_t len)
354 {
355 	struct sockaddr_storage ss;
356 	socklen_t slen = sizeof(ss);
357 
358 	if (addr_xaddr_to_sa(n, _SA(&ss), &slen, 0) == -1)
359 		return -1;
360 	if (n == NULL || p == NULL || len == 0)
361 		return -1;
362 	if (getnameinfo(_SA(&ss), slen, p, len, NULL, 0,
363 	    NI_NUMERICHOST) == -1)
364 		return -1;
365 
366 	return 0;
367 }
368 
369 /*
370  * Parse a CIDR address (x.x.x.x/y or xxxx:yyyy::/z).
371  * Return -1 on parse error, -2 on inconsistency or 0 on success.
372  */
373 int
addr_pton_cidr(const char * p,struct xaddr * n,u_int * l)374 addr_pton_cidr(const char *p, struct xaddr *n, u_int *l)
375 {
376 	struct xaddr tmp;
377 	long unsigned int masklen = 999;
378 	char addrbuf[64], *mp, *cp;
379 
380 	/* Don't modify argument */
381 	if (p == NULL || strlcpy(addrbuf, p, sizeof(addrbuf)) >= sizeof(addrbuf))
382 		return -1;
383 
384 	if ((mp = strchr(addrbuf, '/')) != NULL) {
385 		*mp = '\0';
386 		mp++;
387 		masklen = strtoul(mp, &cp, 10);
388 		if (*mp == '\0' || *cp != '\0' || masklen > 128)
389 			return -1;
390 	}
391 
392 	if (addr_pton(addrbuf, &tmp) == -1)
393 		return -1;
394 
395 	if (mp == NULL)
396 		masklen = addr_unicast_masklen(tmp.af);
397 	if (masklen_valid(tmp.af, masklen) == -1)
398 		return -2;
399 	if (addr_host_is_all0s(&tmp, masklen) != 0)
400 		return -2;
401 
402 	if (n != NULL)
403 		memcpy(n, &tmp, sizeof(*n));
404 	if (l != NULL)
405 		*l = masklen;
406 
407 	return 0;
408 }
409 
410 int
addr_netmatch(const struct xaddr * host,const struct xaddr * net,u_int masklen)411 addr_netmatch(const struct xaddr *host, const struct xaddr *net, u_int masklen)
412 {
413 	struct xaddr tmp_mask, tmp_result;
414 
415 	if (host->af != net->af)
416 		return -1;
417 
418 	if (addr_netmask(host->af, masklen, &tmp_mask) == -1)
419 		return -1;
420 	if (addr_and(&tmp_result, host, &tmp_mask) == -1)
421 		return -1;
422 	return addr_cmp(&tmp_result, net);
423 }
424