1/*-
2 * Copyright (c) 1983, 1990, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifndef lint
35static const char copyright[] =
36"@(#) Copyright (c) 1983, 1990, 1993, 1994\n\
37 The Regents of the University of California. All rights reserved.\n";
38#endif /* not lint */
39
40#ifndef lint
41static const char sccsid[] = "From: @(#)rsh.c 8.3 (Berkeley) 4/6/94";
42#endif /* not lint */
43
44#include <sys/cdefs.h>
45__FBSDID("$FreeBSD: head/usr.bin/rsh/rsh.c 93412 2002-03-30 08:51:21Z obrien $");
46
47#include <sys/param.h>
48#include <sys/signal.h>
49#include <sys/socket.h>
50#include <sys/ioctl.h>
51#include <sys/file.h>
52#include <sys/time.h>
53
54#include <netinet/in.h>
55#include <netdb.h>
56
57#include <err.h>
58#include <errno.h>
59#include <libutil.h>
60#include <pwd.h>
61#include <signal.h>
62#include <stdio.h>
63#include <stdlib.h>
64#include <string.h>
65#include <unistd.h>
66#include <err.h>
67
68#include "pathnames.h"
69
70#ifdef KERBEROS
71#include <openssl/des.h>
72#include <krb.h>
73#include "krb.h"
74
75CREDENTIALS cred;
76Key_schedule schedule;
77int use_kerberos = 1, doencrypt;
78char dst_realm_buf[REALM_SZ], *dest_realm;
79extern char *krb_realmofhost();
80#endif
81
82/*
83 * rsh - remote shell
84 */
85int rfd2;
86
87int family = PF_UNSPEC;
88char rlogin[] = "rlogin";
89
90char *copyargs(char * const *);
91void sendsig(int);
92void talk(int, long, pid_t, int, int);
93void usage(void);
94
95int
96main(int argc, char *argv[])
97{
98 struct passwd const *pw;
99 struct servent const *sp;
100 long omask;
101 int argoff, asrsh, ch, dflag, nflag, one, rem;
102 pid_t pid = 0;
103 uid_t uid;
104 char *args, *host, *p, *user;
105 int timeout = 0;
106#ifdef KERBEROS
107 const char *k;
108#endif
109
110 argoff = asrsh = dflag = nflag = 0;
111 one = 1;
112 host = user = NULL;
113
114 /* if called as something other than "rsh", use it as the host name */
115 if ((p = strrchr(argv[0], '/')))
116 ++p;
117 else
118 p = argv[0];
119 if (strcmp(p, "rsh"))
120 host = p;
121 else
122 asrsh = 1;
123
124 /* handle "rsh host flags" */
125 if (!host && argc > 2 && argv[1][0] != '-') {
126 host = argv[1];
127 argoff = 1;
128 }
129
130#ifdef KERBEROS
131#ifdef CRYPT
132#define OPTIONS "468KLde:k:l:nt:wx"
133#else
134#define OPTIONS "468KLde:k:l:nt:w"
135#endif
136#else
137#define OPTIONS "468KLde:l:nt:w"
138#endif
139 while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != -1)
140 switch(ch) {
141 case '4':
142 family = PF_INET;
143 break;
144
145 case '6':
146 family = PF_INET6;
147 break;
148
149 case 'K':
150#ifdef KERBEROS
151 use_kerberos = 0;
152#endif
153 break;
154 case 'L': /* -8Lew are ignored to allow rlogin aliases */
155 case 'e':
156 case 'w':
157 case '8':
158 break;
159 case 'd':
160 dflag = 1;
161 break;
162 case 'l':
163 user = optarg;
164 break;
165#ifdef KERBEROS
166 case 'k':
167 dest_realm = dst_realm_buf;
168 strncpy(dest_realm, optarg, REALM_SZ);
169 break;
170#endif
171 case 'n':
172 nflag = 1;
173 break;
174#ifdef KERBEROS
175#ifdef CRYPT
176 case 'x':
177 doencrypt = 1;
178 break;
179#endif
180#endif
181 case 't':
182 timeout = atoi(optarg);
183 break;
184 case '?':
185 default:
186 usage();
187 }
188 optind += argoff;
189
190 /* if haven't gotten a host yet, do so */
191 if (!host && !(host = argv[optind++]))
192 usage();
193
194 /* if no further arguments, must have been called as rlogin. */
195 if (!argv[optind]) {
196 if (asrsh)
197 *argv = rlogin;
198 execv(_PATH_RLOGIN, argv);
199 err(1, "can't exec %s", _PATH_RLOGIN);
200 }
201
202 argc -= optind;
203 argv += optind;
204
205 if (!(pw = getpwuid(uid = getuid())))
206 errx(1, "unknown user id");
207 if (!user)
208 user = pw->pw_name;
209
210#ifdef KERBEROS
211#ifdef CRYPT
212 /* -x turns off -n */
213 if (doencrypt)
214 nflag = 0;
215#endif
216#endif
217
218 args = copyargs(argv);
219
220 sp = NULL;
221#ifdef KERBEROS
222 k = auth_getval("auth_list");
223 if (k && !strstr(k, "kerberos"))
224 use_kerberos = 0;
225 if (use_kerberos) {
226 sp = getservbyname((doencrypt ? "ekshell" : "kshell"), "tcp");
227 if (sp == NULL) {
228 use_kerberos = 0;
229 warnx(
230 "warning, using standard rsh: can't get entry for %s/tcp service",
231 doencrypt ? "ekshell" : "kshell");
232 }
233 }
234#endif
235 if (sp == NULL)
236 sp = getservbyname("shell", "tcp");
237 if (sp == NULL)
238 errx(1, "shell/tcp: unknown service");
239
240#ifdef KERBEROS
241try_connect:
242 if (use_kerberos) {
243 struct hostent *hp;
244
245 /* fully qualify hostname (needed for krb_realmofhost) */
246 hp = gethostbyname(host);
247 if (hp != NULL && !(host = strdup(hp->h_name)))
248 err(1, NULL);
249
250 rem = KSUCCESS;
251 errno = 0;
252 if (dest_realm == NULL)
253 dest_realm = krb_realmofhost(host);
254
255#ifdef CRYPT
256 if (doencrypt) {
257 rem = krcmd_mutual(&host, sp->s_port, user, args,
258 &rfd2, dest_realm, &cred, schedule);
259 des_set_key(&cred.session, schedule);
260 } else
261#endif
262 rem = krcmd(&host, sp->s_port, user, args, &rfd2,
263 dest_realm);
264 if (rem < 0) {
265 use_kerberos = 0;
266 sp = getservbyname("shell", "tcp");
267 if (sp == NULL)
268 errx(1, "shell/tcp: unknown service");
269 if (errno == ECONNREFUSED)
270 warnx(
271 "warning, using standard rsh: remote host doesn't support Kerberos");
272 if (errno == ENOENT)
273 warnx(
274 "warning, using standard rsh: can't provide Kerberos auth data");
275 goto try_connect;
276 }
277 } else {
278 if (doencrypt)
279 errx(1, "the -x flag requires Kerberos authentication");
280 rem = rcmd_af(&host, sp->s_port, pw->pw_name, user, args,
281 &rfd2, family);
282 }
283#else
284 rem = rcmd_af(&host, sp->s_port, pw->pw_name, user, args, &rfd2,
285 family);
286#endif
287
288 if (rem < 0)
289 exit(1);
290
291 if (rfd2 < 0)
292 errx(1, "can't establish stderr");
293 if (dflag) {
294 if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one,
295 sizeof(one)) < 0)
296 warn("setsockopt");
297 if (setsockopt(rfd2, SOL_SOCKET, SO_DEBUG, &one,
298 sizeof(one)) < 0)
299 warn("setsockopt");
300 }
301
302 (void)setuid(uid);
303 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGTERM));
304 if (signal(SIGINT, SIG_IGN) != SIG_IGN)
305 (void)signal(SIGINT, sendsig);
306 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
307 (void)signal(SIGQUIT, sendsig);
308 if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
309 (void)signal(SIGTERM, sendsig);
310
311 if (!nflag) {
312 pid = fork();
313 if (pid < 0)
314 err(1, "fork");
315 }
316 else
317 (void)shutdown(rem, 1);
318
319#ifdef KERBEROS
320#ifdef CRYPT
321 if (!doencrypt)
322#endif
323#endif
324 {
325 (void)ioctl(rfd2, FIONBIO, &one);
326 (void)ioctl(rem, FIONBIO, &one);
327 }
328
329 talk(nflag, omask, pid, rem, timeout);
330
331 if (!nflag)
332 (void)kill(pid, SIGKILL);
333 exit(0);
334}
335
336void
337talk(int nflag, long omask, pid_t pid, int rem, int timeout)
338{
339 int cc, wc;
340 fd_set readfrom, ready, rembits;
341 char buf[BUFSIZ];
342 const char *bp;
343 struct timeval tvtimeout;
344 int nfds, srval;
345
346 if (!nflag && pid == 0) {
347 (void)close(rfd2);
348
349reread: errno = 0;
350 if ((cc = read(0, buf, sizeof buf)) <= 0)
351 goto done;
352 bp = buf;
353
354rewrite:
355 FD_ZERO(&rembits);
356 FD_SET(rem, &rembits);
357 nfds = rem + 1;
358 if (select(nfds, 0, &rembits, 0, 0) < 0) {
359 if (errno != EINTR)
360 err(1, "select");
361 goto rewrite;
362 }
363 if (!FD_ISSET(rem, &rembits))
364 goto rewrite;
365#ifdef KERBEROS
366#ifdef CRYPT
367 if (doencrypt)
368 wc = des_enc_write(rem, bp, cc, schedule, &cred.session);
369 else
370#endif
371#endif
372 wc = write(rem, bp, cc);
373 if (wc < 0) {
374 if (errno == EWOULDBLOCK)
375 goto rewrite;
376 goto done;
377 }
378 bp += wc;
379 cc -= wc;
380 if (cc == 0)
381 goto reread;
382 goto rewrite;
383done:
384 (void)shutdown(rem, 1);
385 exit(0);
386 }
387
388 tvtimeout.tv_sec = timeout;
389 tvtimeout.tv_usec = 0;
390
391 (void)sigsetmask(omask);
392 FD_ZERO(&readfrom);
393 FD_SET(rfd2, &readfrom);
394 FD_SET(rem, &readfrom);
395 nfds = MAX(rfd2+1, rem+1);
396 do {
397 ready = readfrom;
398 if (timeout) {
399 srval = select(nfds, &ready, 0, 0, &tvtimeout);
400 } else {
401 srval = select(nfds, &ready, 0, 0, 0);
402 }
403
404 if (srval < 0) {
405 if (errno != EINTR)
406 err(1, "select");
407 continue;
408 }
409 if (srval == 0)
410 errx(1, "timeout reached (%d seconds)\n", timeout);
411 if (FD_ISSET(rfd2, &ready)) {
412 errno = 0;
413#ifdef KERBEROS
414#ifdef CRYPT
415 if (doencrypt)
416 cc = des_enc_read(rfd2, buf, sizeof buf, schedule, &cred.session);
417 else
418#endif
419#endif
420 cc = read(rfd2, buf, sizeof buf);
421 if (cc <= 0) {
422 if (errno != EWOULDBLOCK)
423 FD_CLR(rfd2, &readfrom);
424 } else
425 (void)write(STDERR_FILENO, buf, cc);
426 }
427 if (FD_ISSET(rem, &ready)) {
428 errno = 0;
429#ifdef KERBEROS
430#ifdef CRYPT
431 if (doencrypt)
432 cc = des_enc_read(rem, buf, sizeof buf, schedule, &cred.session);
433 else
434#endif
435#endif
436 cc = read(rem, buf, sizeof buf);
437 if (cc <= 0) {
438 if (errno != EWOULDBLOCK)
439 FD_CLR(rem, &readfrom);
440 } else
441 (void)write(STDOUT_FILENO, buf, cc);
442 }
443 } while (FD_ISSET(rfd2, &readfrom) || FD_ISSET(rem, &readfrom));
444}
445
446void
447sendsig(int sig)
448{
449 char signo;
450
451 signo = sig;
452#ifdef KERBEROS
453#ifdef CRYPT
454 if (doencrypt)
455 (void)des_enc_write(rfd2, &signo, 1, schedule, &cred.session);
456 else
457#endif
458#endif
459 (void)write(rfd2, &signo, 1);
460}
461
462char *
463copyargs(char * const *argv)
464{
465 int cc;
466 char *args, *p;
467 char * const *ap;
468
469 cc = 0;
470 for (ap = argv; *ap; ++ap)
471 cc += strlen(*ap) + 1;
472 if (!(args = malloc((u_int)cc)))
473 err(1, NULL);
474 for (p = args, ap = argv; *ap; ++ap) {
475 (void)strcpy(p, *ap);
476 for (p = strcpy(p, *ap); *p; ++p);
477 if (ap[1])
478 *p++ = ' ';
479 }
480 return (args);
481}
482
483void
484usage(void)
485{
486
487 (void)fprintf(stderr,
488 "usage: rsh [-46] [-ndK%s]%s[-l login] [-t timeout] host [command]\n",
489#ifdef KERBEROS
490#ifdef CRYPT
491 "x", " [-k realm] ");
492#else
493 "", " [-k realm] ");
494#endif
495#else
496 "", " ");
497#endif
498 exit(1);
499}
500