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-rw-r--r--src/lib/libc/net/rcmd.c691
1 files changed, 691 insertions, 0 deletions
diff --git a/src/lib/libc/net/rcmd.c b/src/lib/libc/net/rcmd.c
new file mode 100644
index 0000000000..bfe8c3ae56
--- /dev/null
+++ b/src/lib/libc/net/rcmd.c
@@ -0,0 +1,691 @@
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#if defined(LIBC_SCCS) && !defined(lint)
32static char *rcsid = "$OpenBSD: rcmd.c,v 1.52 2005/03/25 13:24:12 otto Exp $";
33#endif /* LIBC_SCCS and not lint */
34
35#include <sys/param.h>
36#include <sys/socket.h>
37#include <sys/stat.h>
38
39#include <netinet/in.h>
40#include <arpa/inet.h>
41
42#include <signal.h>
43#include <fcntl.h>
44#include <netdb.h>
45#include <unistd.h>
46#include <pwd.h>
47#include <errno.h>
48#include <stdio.h>
49#include <ctype.h>
50#include <string.h>
51#include <syslog.h>
52#include <stdlib.h>
53#include <netgroup.h>
54
55int __ivaliduser(FILE *, in_addr_t, const char *, const char *);
56int __ivaliduser_sa(FILE *, struct sockaddr *, socklen_t,
57 const char *, const char *);
58static int __icheckhost(struct sockaddr *, socklen_t, const char *);
59static char *__gethostloop(struct sockaddr *, socklen_t);
60
61int
62rcmd(char **ahost, int rport, const char *locuser, const char *remuser,
63 const char *cmd, int *fd2p)
64{
65 return rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET);
66}
67
68int
69rcmd_af(char **ahost, int porta, const char *locuser, const char *remuser,
70 const char *cmd, int *fd2p, int af)
71{
72 static char hbuf[MAXHOSTNAMELEN];
73 char pbuf[NI_MAXSERV];
74 struct addrinfo hints, *res, *r;
75 int error;
76 struct sockaddr_storage from;
77 fd_set *readsp = NULL;
78 sigset_t oldmask, mask;
79 pid_t pid;
80 int s, lport, timo;
81 char c, *p;
82 int refused;
83 in_port_t rport = porta;
84
85 /* call rcmdsh() with specified remote shell if appropriate. */
86 if (!issetugid() && (p = getenv("RSH")) && *p) {
87 struct servent *sp = getservbyname("shell", "tcp");
88
89 if (sp && sp->s_port == rport)
90 return (rcmdsh(ahost, rport, locuser, remuser,
91 cmd, p));
92 }
93
94 /* use rsh(1) if non-root and remote port is shell. */
95 if (geteuid()) {
96 struct servent *sp = getservbyname("shell", "tcp");
97
98 if (sp && sp->s_port == rport)
99 return (rcmdsh(ahost, rport, locuser, remuser,
100 cmd, NULL));
101 }
102
103 pid = getpid();
104 snprintf(pbuf, sizeof(pbuf), "%u", ntohs(rport));
105 memset(&hints, 0, sizeof(hints));
106 hints.ai_family = af;
107 hints.ai_socktype = SOCK_STREAM;
108 hints.ai_flags = AI_CANONNAME;
109 error = getaddrinfo(*ahost, pbuf, &hints, &res);
110 if (error) {
111#if 0
112 warnx("%s: %s", *ahost, gai_strerror(error));
113#endif
114 return (-1);
115 }
116 if (res->ai_canonname) {
117 strlcpy(hbuf, res->ai_canonname, sizeof(hbuf));
118 *ahost = hbuf;
119 } else
120 ; /*XXX*/
121
122 r = res;
123 refused = 0;
124 sigemptyset(&mask);
125 sigaddset(&mask, SIGURG);
126 oldmask = sigprocmask(SIG_BLOCK, &mask, &oldmask);
127 for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
128 s = rresvport_af(&lport, r->ai_family);
129 if (s < 0) {
130 if (errno == EAGAIN)
131 (void)fprintf(stderr,
132 "rcmd: socket: All ports in use\n");
133 else
134 (void)fprintf(stderr, "rcmd: socket: %s\n",
135 strerror(errno));
136 if (r->ai_next) {
137 r = r->ai_next;
138 continue;
139 } else {
140 sigprocmask(SIG_SETMASK, &oldmask, NULL);
141 freeaddrinfo(res);
142 return (-1);
143 }
144 }
145 fcntl(s, F_SETOWN, pid);
146 if (connect(s, r->ai_addr, r->ai_addrlen) >= 0)
147 break;
148 (void)close(s);
149 if (errno == EADDRINUSE) {
150 lport--;
151 continue;
152 }
153 if (errno == ECONNREFUSED)
154 refused++;
155 if (r->ai_next) {
156 int oerrno = errno;
157 char hbuf[NI_MAXHOST];
158 const int niflags = NI_NUMERICHOST;
159
160 hbuf[0] = '\0';
161 if (getnameinfo(r->ai_addr, r->ai_addrlen,
162 hbuf, sizeof(hbuf), NULL, 0, niflags) != 0)
163 strlcpy(hbuf, "(invalid)", sizeof hbuf);
164 (void)fprintf(stderr, "connect to address %s: ", hbuf);
165 errno = oerrno;
166 perror(0);
167 r = r->ai_next;
168 hbuf[0] = '\0';
169 if (getnameinfo(r->ai_addr, r->ai_addrlen,
170 hbuf, sizeof(hbuf), NULL, 0, niflags) != 0)
171 strlcpy(hbuf, "(invalid)", sizeof hbuf);
172 (void)fprintf(stderr, "Trying %s...\n", hbuf);
173 continue;
174 }
175 if (refused && timo <= 16) {
176 (void)sleep(timo);
177 timo *= 2;
178 r = res;
179 refused = 0;
180 continue;
181 }
182 (void)fprintf(stderr, "%s: %s\n", res->ai_canonname,
183 strerror(errno));
184 sigprocmask(SIG_SETMASK, &oldmask, NULL);
185 freeaddrinfo(res);
186 return (-1);
187 }
188 /* given "af" can be PF_UNSPEC, we need the real af for "s" */
189 af = r->ai_family;
190 freeaddrinfo(res);
191#if 0
192 /*
193 * try to rresvport() to the same port. This will make rresvport()
194 * fail it's first bind, resulting in it choosing a random port.
195 */
196 lport--;
197#endif
198 if (fd2p == 0) {
199 write(s, "", 1);
200 lport = 0;
201 } else {
202 char num[8];
203 int s2 = rresvport_af(&lport, af), s3;
204 socklen_t len = sizeof(from);
205 int fdssize = howmany(MAX(s, s2)+1, NFDBITS) * sizeof(fd_mask);
206
207 if (s2 < 0)
208 goto bad;
209 readsp = (fd_set *)malloc(fdssize);
210 if (readsp == NULL) {
211 close(s2);
212 goto bad;
213 }
214 listen(s2, 1);
215 (void)snprintf(num, sizeof(num), "%d", lport);
216 if (write(s, num, strlen(num)+1) != strlen(num)+1) {
217 (void)fprintf(stderr,
218 "rcmd: write (setting up stderr): %s\n",
219 strerror(errno));
220 (void)close(s2);
221 goto bad;
222 }
223again:
224 bzero(readsp, fdssize);
225 FD_SET(s, readsp);
226 FD_SET(s2, readsp);
227 errno = 0;
228 if (select(MAX(s, s2) + 1, readsp, 0, 0, 0) < 1 ||
229 !FD_ISSET(s2, readsp)) {
230 if (errno != 0)
231 (void)fprintf(stderr,
232 "rcmd: select (setting up stderr): %s\n",
233 strerror(errno));
234 else
235 (void)fprintf(stderr,
236 "select: protocol failure in circuit setup\n");
237 (void)close(s2);
238 goto bad;
239 }
240 s3 = accept(s2, (struct sockaddr *)&from, &len);
241 if (s3 < 0) {
242 (void)fprintf(stderr,
243 "rcmd: accept: %s\n", strerror(errno));
244 lport = 0;
245 close(s2);
246 goto bad;
247 }
248
249 /*
250 * XXX careful for ftp bounce attacks. If discovered, shut them
251 * down and check for the real auxiliary channel to connect.
252 */
253 switch (from.ss_family) {
254 case AF_INET:
255 case AF_INET6:
256 if (getnameinfo((struct sockaddr *)&from, len,
257 NULL, 0, num, sizeof(num), NI_NUMERICSERV) == 0 &&
258 atoi(num) != 20) {
259 break;
260 }
261 close(s3);
262 goto again;
263 default:
264 break;
265 }
266 (void)close(s2);
267
268 *fd2p = s3;
269 switch (from.ss_family) {
270 case AF_INET:
271 case AF_INET6:
272 if (getnameinfo((struct sockaddr *)&from, len,
273 NULL, 0, num, sizeof(num), NI_NUMERICSERV) != 0 ||
274 (atoi(num) >= IPPORT_RESERVED ||
275 atoi(num) < IPPORT_RESERVED / 2)) {
276 (void)fprintf(stderr,
277 "socket: protocol failure in circuit setup.\n");
278 goto bad2;
279 }
280 break;
281 default:
282 break;
283 }
284 }
285 (void)write(s, locuser, strlen(locuser)+1);
286 (void)write(s, remuser, strlen(remuser)+1);
287 (void)write(s, cmd, strlen(cmd)+1);
288 if (read(s, &c, 1) != 1) {
289 (void)fprintf(stderr,
290 "rcmd: %s: %s\n", *ahost, strerror(errno));
291 goto bad2;
292 }
293 if (c != 0) {
294 while (read(s, &c, 1) == 1) {
295 (void)write(STDERR_FILENO, &c, 1);
296 if (c == '\n')
297 break;
298 }
299 goto bad2;
300 }
301 sigprocmask(SIG_SETMASK, &oldmask, NULL);
302 free(readsp);
303 return (s);
304bad2:
305 if (lport)
306 (void)close(*fd2p);
307bad:
308 if (readsp)
309 free(readsp);
310 (void)close(s);
311 sigprocmask(SIG_SETMASK, &oldmask, NULL);
312 return (-1);
313}
314
315int __check_rhosts_file = 1;
316char *__rcmd_errstr;
317
318int
319ruserok(const char *rhost, int superuser, const char *ruser, const char *luser)
320{
321 struct addrinfo hints, *res, *r;
322 int error;
323
324 memset(&hints, 0, sizeof(hints));
325 hints.ai_family = PF_UNSPEC;
326 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
327 error = getaddrinfo(rhost, "0", &hints, &res);
328 if (error)
329 return (-1);
330
331 for (r = res; r; r = r->ai_next) {
332 if (iruserok_sa(r->ai_addr, r->ai_addrlen, superuser, ruser,
333 luser) == 0) {
334 freeaddrinfo(res);
335 return (0);
336 }
337 }
338 freeaddrinfo(res);
339 return (-1);
340}
341
342/*
343 * New .rhosts strategy: We are passed an ip address. We spin through
344 * hosts.equiv and .rhosts looking for a match. When the .rhosts only
345 * has ip addresses, we don't have to trust a nameserver. When it
346 * contains hostnames, we spin through the list of addresses the nameserver
347 * gives us and look for a match.
348 *
349 * Returns 0 if ok, -1 if not ok.
350 */
351int
352iruserok(u_int32_t raddr, int superuser, const char *ruser, const char *luser)
353{
354 struct sockaddr_in sin;
355
356 memset(&sin, 0, sizeof(sin));
357 sin.sin_family = AF_INET;
358 sin.sin_len = sizeof(struct sockaddr_in);
359 memcpy(&sin.sin_addr, &raddr, sizeof(sin.sin_addr));
360 return iruserok_sa(&sin, sizeof(struct sockaddr_in), superuser, ruser,
361 luser);
362}
363
364int
365iruserok_sa(const void *raddr, int rlen, int superuser, const char *ruser,
366 const char *luser)
367{
368 struct sockaddr *sa;
369 char *cp;
370 struct stat sbuf;
371 struct passwd *pwd;
372 FILE *hostf;
373 uid_t uid;
374 int first;
375 char pbuf[MAXPATHLEN];
376
377 sa = (struct sockaddr *)raddr;
378 first = 1;
379 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
380again:
381 if (hostf) {
382 if (__ivaliduser_sa(hostf, sa, rlen, luser, ruser) == 0) {
383 (void)fclose(hostf);
384 return (0);
385 }
386 (void)fclose(hostf);
387 }
388 if (first == 1 && (__check_rhosts_file || superuser)) {
389 first = 0;
390 if ((pwd = getpwnam(luser)) == NULL)
391 return (-1);
392 snprintf(pbuf, sizeof pbuf, "%s/.rhosts", pwd->pw_dir);
393
394 /*
395 * Change effective uid while opening .rhosts. If root and
396 * reading an NFS mounted file system, can't read files that
397 * are protected read/write owner only.
398 */
399 uid = geteuid();
400 (void)seteuid(pwd->pw_uid);
401 hostf = fopen(pbuf, "r");
402 (void)seteuid(uid);
403
404 if (hostf == NULL)
405 return (-1);
406 /*
407 * If not a regular file, or is owned by someone other than
408 * user or root or if writeable by anyone but the owner, quit.
409 */
410 cp = NULL;
411 if (lstat(pbuf, &sbuf) < 0)
412 cp = ".rhosts lstat failed";
413 else if (!S_ISREG(sbuf.st_mode))
414 cp = ".rhosts not regular file";
415 else if (fstat(fileno(hostf), &sbuf) < 0)
416 cp = ".rhosts fstat failed";
417 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
418 cp = "bad .rhosts owner";
419 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
420 cp = ".rhosts writable by other than owner";
421 /* If there were any problems, quit. */
422 if (cp) {
423 __rcmd_errstr = cp;
424 (void)fclose(hostf);
425 return (-1);
426 }
427 goto again;
428 }
429 return (-1);
430}
431
432/*
433 * XXX
434 * Don't make static, used by lpd(8).
435 *
436 * Returns 0 if ok, -1 if not ok.
437 */
438int
439__ivaliduser(FILE *hostf, in_addr_t raddrl, const char *luser,
440 const char *ruser)
441{
442 struct sockaddr_in sin;
443
444 memset(&sin, 0, sizeof(sin));
445 sin.sin_family = AF_INET;
446 sin.sin_len = sizeof(struct sockaddr_in);
447 memcpy(&sin.sin_addr, &raddrl, sizeof(sin.sin_addr));
448 return __ivaliduser_sa(hostf, (struct sockaddr *)&sin, sin.sin_len,
449 luser, ruser);
450}
451
452int
453__ivaliduser_sa(FILE *hostf, struct sockaddr *raddr, socklen_t salen,
454 const char *luser, const char *ruser)
455{
456 char *user, *p;
457 char *buf;
458 const char *auser, *ahost;
459 int hostok, userok;
460 char *rhost = (char *)-1;
461 char domain[MAXHOSTNAMELEN];
462 size_t buflen;
463
464 getdomainname(domain, sizeof(domain));
465
466 while ((buf = fgetln(hostf, &buflen))) {
467 p = buf;
468 if (*p == '#')
469 continue;
470 while (p < buf + buflen && *p != '\n' && *p != ' ' && *p != '\t') {
471 if (!isprint(*p))
472 goto bail;
473 *p = isupper(*p) ? tolower(*p) : *p;
474 p++;
475 }
476 if (p >= buf + buflen)
477 continue;
478 if (*p == ' ' || *p == '\t') {
479 *p++ = '\0';
480 while (p < buf + buflen && (*p == ' ' || *p == '\t'))
481 p++;
482 if (p >= buf + buflen)
483 continue;
484 user = p;
485 while (p < buf + buflen && *p != '\n' && *p != ' ' &&
486 *p != '\t') {
487 if (!isprint(*p))
488 goto bail;
489 p++;
490 }
491 } else
492 user = p;
493 *p = '\0';
494
495 if (p == buf)
496 continue;
497
498 auser = *user ? user : luser;
499 ahost = buf;
500
501 if (strlen(ahost) >= MAXHOSTNAMELEN)
502 continue;
503
504 /*
505 * innetgr() must lookup a hostname (we do not attempt
506 * to change the semantics so that netgroups may have
507 * #.#.#.# addresses in the list.)
508 */
509 if (ahost[0] == '+')
510 switch (ahost[1]) {
511 case '\0':
512 hostok = 1;
513 break;
514 case '@':
515 if (rhost == (char *)-1)
516 rhost = __gethostloop(raddr, salen);
517 hostok = 0;
518 if (rhost)
519 hostok = innetgr(&ahost[2], rhost,
520 NULL, domain);
521 break;
522 default:
523 hostok = __icheckhost(raddr, salen, &ahost[1]);
524 break;
525 }
526 else if (ahost[0] == '-')
527 switch (ahost[1]) {
528 case '\0':
529 hostok = -1;
530 break;
531 case '@':
532 if (rhost == (char *)-1)
533 rhost = __gethostloop(raddr, salen);
534 hostok = 0;
535 if (rhost)
536 hostok = -innetgr(&ahost[2], rhost,
537 NULL, domain);
538 break;
539 default:
540 hostok = -__icheckhost(raddr, salen, &ahost[1]);
541 break;
542 }
543 else
544 hostok = __icheckhost(raddr, salen, ahost);
545
546
547 if (auser[0] == '+')
548 switch (auser[1]) {
549 case '\0':
550 userok = 1;
551 break;
552 case '@':
553 userok = innetgr(&auser[2], NULL, ruser,
554 domain);
555 break;
556 default:
557 userok = strcmp(ruser, &auser[1]) ? 0 : 1;
558 break;
559 }
560 else if (auser[0] == '-')
561 switch (auser[1]) {
562 case '\0':
563 userok = -1;
564 break;
565 case '@':
566 userok = -innetgr(&auser[2], NULL, ruser,
567 domain);
568 break;
569 default:
570 userok = strcmp(ruser, &auser[1]) ? 0 : -1;
571 break;
572 }
573 else
574 userok = strcmp(ruser, auser) ? 0 : 1;
575
576 /* Check if one component did not match */
577 if (hostok == 0 || userok == 0)
578 continue;
579
580 /* Check if we got a forbidden pair */
581 if (userok <= -1 || hostok <= -1)
582 return (-1);
583
584 /* Check if we got a valid pair */
585 if (hostok >= 1 && userok >= 1)
586 return (0);
587 }
588bail:
589 return (-1);
590}
591
592/*
593 * Returns "true" if match, 0 if no match. If we do not find any
594 * semblance of an A->PTR->A loop, allow a simple #.#.#.# match to work.
595 */
596static int
597__icheckhost(struct sockaddr *raddr, socklen_t salen, const char *lhost)
598{
599 struct addrinfo hints, *res, *r;
600 char h1[NI_MAXHOST], h2[NI_MAXHOST];
601 int error;
602 const int niflags = NI_NUMERICHOST;
603
604 h1[0] = '\0';
605 if (getnameinfo(raddr, salen, h1, sizeof(h1), NULL, 0,
606 niflags) != 0)
607 return (0);
608
609 /* Resolve laddr into sockaddr */
610 memset(&hints, 0, sizeof(hints));
611 hints.ai_family = raddr->sa_family;
612 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
613 res = NULL;
614 error = getaddrinfo(lhost, "0", &hints, &res);
615 if (error)
616 return (0);
617
618 /*
619 * Try string comparisons between raddr and laddr.
620 */
621 for (r = res; r; r = r->ai_next) {
622 h2[0] = '\0';
623 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2),
624 NULL, 0, niflags) != 0)
625 continue;
626 if (strcmp(h1, h2) == 0) {
627 freeaddrinfo(res);
628 return (1);
629 }
630 }
631
632 /* No match. */
633 freeaddrinfo(res);
634 return (0);
635}
636
637/*
638 * Return the hostname associated with the supplied address.
639 * Do a reverse lookup as well for security. If a loop cannot
640 * be found, pack the result of inet_ntoa() into the string.
641 */
642static char *
643__gethostloop(struct sockaddr *raddr, socklen_t salen)
644{
645 static char remotehost[NI_MAXHOST];
646 char h1[NI_MAXHOST], h2[NI_MAXHOST];
647 struct addrinfo hints, *res, *r;
648 int error;
649 const int niflags = NI_NUMERICHOST;
650
651 h1[0] = remotehost[0] = '\0';
652 if (getnameinfo(raddr, salen, remotehost, sizeof(remotehost),
653 NULL, 0, NI_NAMEREQD) != 0)
654 return (NULL);
655 if (getnameinfo(raddr, salen, h1, sizeof(h1), NULL, 0,
656 niflags) != 0)
657 return (NULL);
658
659 /*
660 * Look up the name and check that the supplied
661 * address is in the list
662 */
663 memset(&hints, 0, sizeof(hints));
664 hints.ai_family = raddr->sa_family;
665 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
666 hints.ai_flags = AI_CANONNAME;
667 res = NULL;
668 error = getaddrinfo(remotehost, "0", &hints, &res);
669 if (error)
670 return (NULL);
671
672 for (r = res; r; r = r->ai_next) {
673 h2[0] = '\0';
674 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2),
675 NULL, 0, niflags) != 0)
676 continue;
677 if (strcmp(h1, h2) == 0) {
678 freeaddrinfo(res);
679 return (remotehost);
680 }
681 }
682
683 /*
684 * either the DNS adminstrator has made a configuration
685 * mistake, or someone has attempted to spoof us
686 */
687 syslog(LOG_NOTICE, "rcmd: address %s not listed for host %s",
688 h1, res->ai_canonname ? res->ai_canonname : remotehost);
689 freeaddrinfo(res);
690 return (NULL);
691}