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-rw-r--r--src/lib/libc/net/ruserok.c438
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diff --git a/src/lib/libc/net/ruserok.c b/src/lib/libc/net/ruserok.c
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1/*
2 * Copyright (c) 1995, 1996, 1998 Theo de Raadt. All rights reserved.
3 * Copyright (c) 1983, 1993, 1994
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <sys/socket.h>
32#include <sys/stat.h>
33
34#include <netinet/in.h>
35#include <arpa/inet.h>
36
37#include <ctype.h>
38#include <errno.h>
39#include <fcntl.h>
40#include <limits.h>
41#include <netdb.h>
42#include <netgroup.h>
43#include <pwd.h>
44#include <signal.h>
45#include <stdio.h>
46#include <stdlib.h>
47#include <string.h>
48#include <syslog.h>
49#include <unistd.h>
50
51int __ivaliduser(FILE *, in_addr_t, const char *, const char *);
52int __ivaliduser_sa(FILE *, struct sockaddr *, socklen_t,
53 const char *, const char *);
54static int __icheckhost(struct sockaddr *, socklen_t, const char *);
55static char *__gethostloop(struct sockaddr *, socklen_t);
56
57int __check_rhosts_file = 1;
58char *__rcmd_errstr;
59
60int
61ruserok(const char *rhost, int superuser, const char *ruser, const char *luser)
62{
63 struct addrinfo hints, *res, *r;
64 int error;
65
66 memset(&hints, 0, sizeof(hints));
67 hints.ai_family = PF_UNSPEC;
68 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
69 error = getaddrinfo(rhost, "0", &hints, &res);
70 if (error)
71 return (-1);
72
73 for (r = res; r; r = r->ai_next) {
74 if (iruserok_sa(r->ai_addr, r->ai_addrlen, superuser, ruser,
75 luser) == 0) {
76 freeaddrinfo(res);
77 return (0);
78 }
79 }
80 freeaddrinfo(res);
81 return (-1);
82}
83
84/*
85 * New .rhosts strategy: We are passed an ip address. We spin through
86 * hosts.equiv and .rhosts looking for a match. When the .rhosts only
87 * has ip addresses, we don't have to trust a nameserver. When it
88 * contains hostnames, we spin through the list of addresses the nameserver
89 * gives us and look for a match.
90 *
91 * Returns 0 if ok, -1 if not ok.
92 */
93int
94iruserok(u_int32_t raddr, int superuser, const char *ruser, const char *luser)
95{
96 struct sockaddr_in sin;
97
98 memset(&sin, 0, sizeof(sin));
99 sin.sin_family = AF_INET;
100 sin.sin_len = sizeof(struct sockaddr_in);
101 memcpy(&sin.sin_addr, &raddr, sizeof(sin.sin_addr));
102 return iruserok_sa(&sin, sizeof(struct sockaddr_in), superuser, ruser,
103 luser);
104}
105
106int
107iruserok_sa(const void *raddr, int rlen, int superuser, const char *ruser,
108 const char *luser)
109{
110 struct sockaddr *sa;
111 char *cp;
112 struct stat sbuf;
113 struct passwd *pwd;
114 FILE *hostf;
115 uid_t uid;
116 int first;
117 char pbuf[PATH_MAX];
118
119 sa = (struct sockaddr *)raddr;
120 first = 1;
121 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
122again:
123 if (hostf) {
124 if (__ivaliduser_sa(hostf, sa, rlen, luser, ruser) == 0) {
125 (void)fclose(hostf);
126 return (0);
127 }
128 (void)fclose(hostf);
129 }
130 if (first == 1 && (__check_rhosts_file || superuser)) {
131 int len;
132
133 first = 0;
134 if ((pwd = getpwnam(luser)) == NULL)
135 return (-1);
136 len = snprintf(pbuf, sizeof pbuf, "%s/.rhosts", pwd->pw_dir);
137 if (len < 0 || len >= sizeof pbuf)
138 return (-1);
139
140 /*
141 * Change effective uid while opening .rhosts. If root and
142 * reading an NFS mounted file system, can't read files that
143 * are protected read/write owner only.
144 */
145 uid = geteuid();
146 (void)seteuid(pwd->pw_uid);
147 hostf = fopen(pbuf, "r");
148 (void)seteuid(uid);
149
150 if (hostf == NULL)
151 return (-1);
152 /*
153 * If not a regular file, or is owned by someone other than
154 * user or root or if writeable by anyone but the owner, quit.
155 */
156 cp = NULL;
157 if (lstat(pbuf, &sbuf) < 0)
158 cp = ".rhosts lstat failed";
159 else if (!S_ISREG(sbuf.st_mode))
160 cp = ".rhosts not regular file";
161 else if (fstat(fileno(hostf), &sbuf) < 0)
162 cp = ".rhosts fstat failed";
163 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
164 cp = "bad .rhosts owner";
165 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
166 cp = ".rhosts writable by other than owner";
167 /* If there were any problems, quit. */
168 if (cp) {
169 __rcmd_errstr = cp;
170 (void)fclose(hostf);
171 return (-1);
172 }
173 goto again;
174 }
175 return (-1);
176}
177
178/*
179 * XXX
180 * Don't make static, used by lpd(8).
181 *
182 * Returns 0 if ok, -1 if not ok.
183 */
184int
185__ivaliduser(FILE *hostf, in_addr_t raddrl, const char *luser,
186 const char *ruser)
187{
188 struct sockaddr_in sin;
189
190 memset(&sin, 0, sizeof(sin));
191 sin.sin_family = AF_INET;
192 sin.sin_len = sizeof(struct sockaddr_in);
193 memcpy(&sin.sin_addr, &raddrl, sizeof(sin.sin_addr));
194 return __ivaliduser_sa(hostf, (struct sockaddr *)&sin, sin.sin_len,
195 luser, ruser);
196}
197
198int
199__ivaliduser_sa(FILE *hostf, struct sockaddr *raddr, socklen_t salen,
200 const char *luser, const char *ruser)
201{
202 char *user, *p;
203 char *buf;
204 const char *auser, *ahost;
205 int hostok, userok;
206 char *rhost = (char *)-1;
207 char domain[MAXHOSTNAMELEN];
208 size_t buflen;
209
210 getdomainname(domain, sizeof(domain));
211
212 while ((buf = fgetln(hostf, &buflen))) {
213 p = buf;
214 if (*p == '#')
215 continue;
216 while (p < buf + buflen && *p != '\n' && *p != ' ' && *p != '\t') {
217 if (!isprint((unsigned char)*p))
218 goto bail;
219 *p = isupper((unsigned char)*p) ?
220 tolower((unsigned char)*p) : *p;
221 p++;
222 }
223 if (p >= buf + buflen)
224 continue;
225 if (*p == ' ' || *p == '\t') {
226 *p++ = '\0';
227 while (p < buf + buflen && (*p == ' ' || *p == '\t'))
228 p++;
229 if (p >= buf + buflen)
230 continue;
231 user = p;
232 while (p < buf + buflen && *p != '\n' && *p != ' ' &&
233 *p != '\t') {
234 if (!isprint((unsigned char)*p))
235 goto bail;
236 p++;
237 }
238 } else
239 user = p;
240 *p = '\0';
241
242 if (p == buf)
243 continue;
244
245 auser = *user ? user : luser;
246 ahost = buf;
247
248 if (strlen(ahost) >= MAXHOSTNAMELEN)
249 continue;
250
251 /*
252 * innetgr() must lookup a hostname (we do not attempt
253 * to change the semantics so that netgroups may have
254 * #.#.#.# addresses in the list.)
255 */
256 if (ahost[0] == '+')
257 switch (ahost[1]) {
258 case '\0':
259 hostok = 1;
260 break;
261 case '@':
262 if (rhost == (char *)-1)
263 rhost = __gethostloop(raddr, salen);
264 hostok = 0;
265 if (rhost)
266 hostok = innetgr(&ahost[2], rhost,
267 NULL, domain);
268 break;
269 default:
270 hostok = __icheckhost(raddr, salen, &ahost[1]);
271 break;
272 }
273 else if (ahost[0] == '-')
274 switch (ahost[1]) {
275 case '\0':
276 hostok = -1;
277 break;
278 case '@':
279 if (rhost == (char *)-1)
280 rhost = __gethostloop(raddr, salen);
281 hostok = 0;
282 if (rhost)
283 hostok = -innetgr(&ahost[2], rhost,
284 NULL, domain);
285 break;
286 default:
287 hostok = -__icheckhost(raddr, salen, &ahost[1]);
288 break;
289 }
290 else
291 hostok = __icheckhost(raddr, salen, ahost);
292
293
294 if (auser[0] == '+')
295 switch (auser[1]) {
296 case '\0':
297 userok = 1;
298 break;
299 case '@':
300 userok = innetgr(&auser[2], NULL, ruser,
301 domain);
302 break;
303 default:
304 userok = strcmp(ruser, &auser[1]) ? 0 : 1;
305 break;
306 }
307 else if (auser[0] == '-')
308 switch (auser[1]) {
309 case '\0':
310 userok = -1;
311 break;
312 case '@':
313 userok = -innetgr(&auser[2], NULL, ruser,
314 domain);
315 break;
316 default:
317 userok = strcmp(ruser, &auser[1]) ? 0 : -1;
318 break;
319 }
320 else
321 userok = strcmp(ruser, auser) ? 0 : 1;
322
323 /* Check if one component did not match */
324 if (hostok == 0 || userok == 0)
325 continue;
326
327 /* Check if we got a forbidden pair */
328 if (userok <= -1 || hostok <= -1)
329 return (-1);
330
331 /* Check if we got a valid pair */
332 if (hostok >= 1 && userok >= 1)
333 return (0);
334 }
335bail:
336 return (-1);
337}
338
339/*
340 * Returns "true" if match, 0 if no match. If we do not find any
341 * semblance of an A->PTR->A loop, allow a simple #.#.#.# match to work.
342 */
343static int
344__icheckhost(struct sockaddr *raddr, socklen_t salen, const char *lhost)
345{
346 struct addrinfo hints, *res, *r;
347 char h1[NI_MAXHOST], h2[NI_MAXHOST];
348 int error;
349 const int niflags = NI_NUMERICHOST;
350
351 h1[0] = '\0';
352 if (getnameinfo(raddr, salen, h1, sizeof(h1), NULL, 0,
353 niflags) != 0)
354 return (0);
355
356 /* Resolve laddr into sockaddr */
357 memset(&hints, 0, sizeof(hints));
358 hints.ai_family = raddr->sa_family;
359 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
360 res = NULL;
361 error = getaddrinfo(lhost, "0", &hints, &res);
362 if (error)
363 return (0);
364
365 /*
366 * Try string comparisons between raddr and laddr.
367 */
368 for (r = res; r; r = r->ai_next) {
369 h2[0] = '\0';
370 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2),
371 NULL, 0, niflags) != 0)
372 continue;
373 if (strcmp(h1, h2) == 0) {
374 freeaddrinfo(res);
375 return (1);
376 }
377 }
378
379 /* No match. */
380 freeaddrinfo(res);
381 return (0);
382}
383
384/*
385 * Return the hostname associated with the supplied address.
386 * Do a reverse lookup as well for security. If a loop cannot
387 * be found, pack the result of inet_ntoa() into the string.
388 */
389static char *
390__gethostloop(struct sockaddr *raddr, socklen_t salen)
391{
392 static char remotehost[NI_MAXHOST];
393 char h1[NI_MAXHOST], h2[NI_MAXHOST];
394 struct addrinfo hints, *res, *r;
395 int error;
396 const int niflags = NI_NUMERICHOST;
397
398 h1[0] = remotehost[0] = '\0';
399 if (getnameinfo(raddr, salen, remotehost, sizeof(remotehost),
400 NULL, 0, NI_NAMEREQD) != 0)
401 return (NULL);
402 if (getnameinfo(raddr, salen, h1, sizeof(h1), NULL, 0,
403 niflags) != 0)
404 return (NULL);
405
406 /*
407 * Look up the name and check that the supplied
408 * address is in the list
409 */
410 memset(&hints, 0, sizeof(hints));
411 hints.ai_family = raddr->sa_family;
412 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
413 hints.ai_flags = AI_CANONNAME;
414 res = NULL;
415 error = getaddrinfo(remotehost, "0", &hints, &res);
416 if (error)
417 return (NULL);
418
419 for (r = res; r; r = r->ai_next) {
420 h2[0] = '\0';
421 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2),
422 NULL, 0, niflags) != 0)
423 continue;
424 if (strcmp(h1, h2) == 0) {
425 freeaddrinfo(res);
426 return (remotehost);
427 }
428 }
429
430 /*
431 * either the DNS adminstrator has made a configuration
432 * mistake, or someone has attempted to spoof us
433 */
434 syslog(LOG_NOTICE, "rcmd: address %s not listed for host %s",
435 h1, res->ai_canonname ? res->ai_canonname : remotehost);
436 freeaddrinfo(res);
437 return (NULL);
438}
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