rsh.c revision 29922 
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
41#if 0
42static char sccsid[] = "From: @(#)rsh.c	8.3 (Berkeley) 4/6/94";
43#endif
44static char rcsid[] =
45	"$Id$";
46#endif /* not lint */
47
48#include <sys/types.h>
49#include <sys/signal.h>
50#include <sys/socket.h>
51#include <sys/ioctl.h>
52#include <sys/file.h>
53#include <sys/time.h>
54
55#include <netinet/in.h>
56#include <netdb.h>
57
58#include <err.h>
59#include <errno.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 <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
87char   *copyargs __P((char **));
88void	sendsig __P((int));
89void	talk __P((int, long, pid_t, int, int));
90void	usage __P((void));
91
92int
93main(argc, argv)
94	int argc;
95	char **argv;
96{
97	struct passwd *pw;
98	struct servent *sp;
99	long omask;
100	int argoff, asrsh, ch, dflag, nflag, one, rem;
101	pid_t pid;
102	uid_t uid;
103	char *args, *host, *p, *user;
104	int timeout = 0;
105
106	argoff = asrsh = dflag = nflag = 0;
107	one = 1;
108	host = user = NULL;
109
110	/* if called as something other than "rsh", use it as the host name */
111	if ((p = strrchr(argv[0], '/')))
112		++p;
113	else
114		p = argv[0];
115	if (strcmp(p, "rsh"))
116		host = p;
117	else
118		asrsh = 1;
119
120	/* handle "rsh host flags" */
121	if (!host && argc > 2 && argv[1][0] != '-') {
122		host = argv[1];
123		argoff = 1;
124	}
125
126#ifdef KERBEROS
127#ifdef CRYPT
128#define	OPTIONS	"8KLde:k:l:nt:wx"
129#else
130#define	OPTIONS	"8KLde:k:l:nt:w"
131#endif
132#else
133#define	OPTIONS	"8KLde:l:nt:w"
134#endif
135	while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != -1)
136		switch(ch) {
137		case 'K':
138#ifdef KERBEROS
139			use_kerberos = 0;
140#endif
141			break;
142		case 'L':	/* -8Lew are ignored to allow rlogin aliases */
143		case 'e':
144		case 'w':
145		case '8':
146			break;
147		case 'd':
148			dflag = 1;
149			break;
150		case 'l':
151			user = optarg;
152			break;
153#ifdef KERBEROS
154		case 'k':
155			dest_realm = dst_realm_buf;
156			strncpy(dest_realm, optarg, REALM_SZ);
157			break;
158#endif
159		case 'n':
160			nflag = 1;
161			break;
162#ifdef KERBEROS
163#ifdef CRYPT
164		case 'x':
165			doencrypt = 1;
166			break;
167#endif
168#endif
169		case 't':
170			timeout = atoi(optarg);
171			break;
172		case '?':
173		default:
174			usage();
175		}
176	optind += argoff;
177
178	/* if haven't gotten a host yet, do so */
179	if (!host && !(host = argv[optind++]))
180		usage();
181
182	/* if no further arguments, must have been called as rlogin. */
183	if (!argv[optind]) {
184		if (asrsh)
185			*argv = "rlogin";
186		execv(_PATH_RLOGIN, argv);
187		err(1, "can't exec %s", _PATH_RLOGIN);
188	}
189
190	argc -= optind;
191	argv += optind;
192
193	if (!(pw = getpwuid(uid = getuid())))
194		errx(1, "unknown user id");
195	if (!user)
196		user = pw->pw_name;
197
198#ifdef KERBEROS
199#ifdef CRYPT
200	/* -x turns off -n */
201	if (doencrypt)
202		nflag = 0;
203#endif
204#endif
205
206	args = copyargs(argv);
207
208	sp = NULL;
209#ifdef KERBEROS
210	if (use_kerberos) {
211		sp = getservbyname((doencrypt ? "ekshell" : "kshell"), "tcp");
212		if (sp == NULL) {
213			use_kerberos = 0;
214			warnx(
215	"warning, using standard rsh: can't get entry for %s/tcp service",
216			    doencrypt ? "ekshell" : "kshell");
217		}
218	}
219#endif
220	if (sp == NULL)
221		sp = getservbyname("shell", "tcp");
222	if (sp == NULL)
223		errx(1, "shell/tcp: unknown service");
224
225#ifdef KERBEROS
226try_connect:
227	if (use_kerberos) {
228		struct hostent *hp;
229
230		/* fully qualify hostname (needed for krb_realmofhost) */
231		hp = gethostbyname(host);
232		if (hp != NULL && !(host = strdup(hp->h_name)))
233			err(1, NULL);
234
235		rem = KSUCCESS;
236		errno = 0;
237		if (dest_realm == NULL)
238			dest_realm = krb_realmofhost(host);
239
240#ifdef CRYPT
241		if (doencrypt) {
242			rem = krcmd_mutual(&host, sp->s_port, user, args,
243			    &rfd2, dest_realm, &cred, schedule);
244			des_set_key(&cred.session, schedule);
245		} else
246#endif
247			rem = krcmd(&host, sp->s_port, user, args, &rfd2,
248			    dest_realm);
249		if (rem < 0) {
250			use_kerberos = 0;
251			sp = getservbyname("shell", "tcp");
252			if (sp == NULL)
253				errx(1, "shell/tcp: unknown service");
254			if (errno == ECONNREFUSED)
255				warnx(
256		"warning, using standard rsh: remote host doesn't support Kerberos");
257			if (errno == ENOENT)
258				warnx(
259		"warning, using standard rsh: can't provide Kerberos auth data");
260			goto try_connect;
261		}
262	} else {
263		if (doencrypt)
264			errx(1, "the -x flag requires Kerberos authentication");
265		rem = rcmd(&host, sp->s_port, pw->pw_name, user, args, &rfd2);
266	}
267#else
268	rem = rcmd(&host, sp->s_port, pw->pw_name, user, args, &rfd2);
269#endif
270
271	if (rem < 0)
272		exit(1);
273
274	if (rfd2 < 0)
275		errx(1, "can't establish stderr");
276	if (dflag) {
277		if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one,
278		    sizeof(one)) < 0)
279			warn("setsockopt");
280		if (setsockopt(rfd2, SOL_SOCKET, SO_DEBUG, &one,
281		    sizeof(one)) < 0)
282			warn("setsockopt");
283	}
284
285	(void)setuid(uid);
286	omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGTERM));
287	if (signal(SIGINT, SIG_IGN) != SIG_IGN)
288		(void)signal(SIGINT, sendsig);
289	if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
290		(void)signal(SIGQUIT, sendsig);
291	if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
292		(void)signal(SIGTERM, sendsig);
293
294	if (!nflag) {
295		pid = fork();
296		if (pid < 0)
297			err(1, "fork");
298	}
299
300#ifdef KERBEROS
301#ifdef CRYPT
302	if (!doencrypt)
303#endif
304#endif
305	{
306		(void)ioctl(rfd2, FIONBIO, &one);
307		(void)ioctl(rem, FIONBIO, &one);
308	}
309
310	talk(nflag, omask, pid, rem, timeout);
311
312	if (!nflag)
313		(void)kill(pid, SIGKILL);
314	exit(0);
315}
316
317void
318talk(nflag, omask, pid, rem, timeout)
319	int nflag;
320	long omask;
321	pid_t pid;
322	int rem;
323{
324	int cc, wc;
325	fd_set readfrom, ready, rembits;
326	char *bp, buf[BUFSIZ];
327	struct timeval tvtimeout;
328	int srval;
329
330	if (!nflag && pid == 0) {
331		(void)close(rfd2);
332
333reread:		errno = 0;
334		if ((cc = read(0, buf, sizeof buf)) <= 0)
335			goto done;
336		bp = buf;
337
338rewrite:
339		FD_ZERO(&rembits);
340		FD_SET(rem, &rembits);
341		if (select(16, 0, &rembits, 0, 0) < 0) {
342			if (errno != EINTR)
343				err(1, "select");
344			goto rewrite;
345		}
346		if (!FD_ISSET(rem, &rembits))
347			goto rewrite;
348#ifdef KERBEROS
349#ifdef CRYPT
350		if (doencrypt)
351			wc = des_enc_write(rem, bp, cc, schedule, &cred.session);
352		else
353#endif
354#endif
355			wc = write(rem, bp, cc);
356		if (wc < 0) {
357			if (errno == EWOULDBLOCK)
358				goto rewrite;
359			goto done;
360		}
361		bp += wc;
362		cc -= wc;
363		if (cc == 0)
364			goto reread;
365		goto rewrite;
366done:
367		(void)shutdown(rem, 1);
368		exit(0);
369	}
370
371	tvtimeout.tv_sec = timeout;
372	tvtimeout.tv_usec = 0;
373
374	(void)sigsetmask(omask);
375	FD_ZERO(&readfrom);
376	FD_SET(rfd2, &readfrom);
377	FD_SET(rem, &readfrom);
378	do {
379		ready = readfrom;
380		if (timeout) {
381			srval = select(16, &ready, 0, 0, &tvtimeout);
382		} else {
383			srval = select(16, &ready, 0, 0, 0);
384		}
385
386		if (srval < 0) {
387			if (errno != EINTR)
388				err(1, "select");
389			continue;
390		}
391		if (srval == 0)
392			errx(1, "timeout reached (%d seconds)\n", timeout);
393		if (FD_ISSET(rfd2, &ready)) {
394			errno = 0;
395#ifdef KERBEROS
396#ifdef CRYPT
397			if (doencrypt)
398				cc = des_enc_read(rfd2, buf, sizeof buf, schedule, &cred.session);
399			else
400#endif
401#endif
402				cc = read(rfd2, buf, sizeof buf);
403			if (cc <= 0) {
404				if (errno != EWOULDBLOCK)
405					FD_CLR(rfd2, &readfrom);
406			} else
407				(void)write(2, buf, cc);
408		}
409		if (FD_ISSET(rem, &ready)) {
410			errno = 0;
411#ifdef KERBEROS
412#ifdef CRYPT
413			if (doencrypt)
414				cc = des_enc_read(rem, buf, sizeof buf, schedule, &cred.session);
415			else
416#endif
417#endif
418				cc = read(rem, buf, sizeof buf);
419			if (cc <= 0) {
420				if (errno != EWOULDBLOCK)
421					FD_CLR(rem, &readfrom);
422			} else
423				(void)write(1, buf, cc);
424		}
425	} while (FD_ISSET(rfd2, &readfrom) || FD_ISSET(rem, &readfrom));
426}
427
428void
429sendsig(sig)
430	int sig;
431{
432	char signo;
433
434	signo = sig;
435#ifdef KERBEROS
436#ifdef CRYPT
437	if (doencrypt)
438		(void)des_enc_write(rfd2, &signo, 1, schedule, &cred.session);
439	else
440#endif
441#endif
442		(void)write(rfd2, &signo, 1);
443}
444
445char *
446copyargs(argv)
447	char **argv;
448{
449	int cc;
450	char **ap, *args, *p;
451
452	cc = 0;
453	for (ap = argv; *ap; ++ap)
454		cc += strlen(*ap) + 1;
455	if (!(args = malloc((u_int)cc)))
456		err(1, NULL);
457	for (p = args, ap = argv; *ap; ++ap) {
458		(void)strcpy(p, *ap);
459		for (p = strcpy(p, *ap); *p; ++p);
460		if (ap[1])
461			*p++ = ' ';
462	}
463	return (args);
464}
465
466void
467usage()
468{
469
470	(void)fprintf(stderr,
471	    "usage: rsh [-nd%s]%s[-l login] [-t timeout] host [command]\n",
472#ifdef KERBEROS
473#ifdef CRYPT
474	    "x", " [-k realm] ");
475#else
476	    "", " [-k realm] ");
477#endif
478#else
479	    "", " ");
480#endif
481	exit(1);
482}
483
484