rsh.c revision 57232 
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 const char rcsid[] =
45  "$FreeBSD: head/usr.bin/rsh/rsh.c 57232 2000-02-15 15:11:40Z shin $";
46#endif /* not lint */
47
48#include <sys/param.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 <libutil.h>
61#include <pwd.h>
62#include <signal.h>
63#include <stdio.h>
64#include <stdlib.h>
65#include <string.h>
66#include <unistd.h>
67#include <err.h>
68
69#include "pathnames.h"
70
71#ifdef KERBEROS
72#include <des.h>
73#include <krb.h>
74#include "krb.h"
75
76CREDENTIALS cred;
77Key_schedule schedule;
78int use_kerberos = 1, doencrypt;
79char dst_realm_buf[REALM_SZ], *dest_realm;
80extern char *krb_realmofhost();
81#endif
82
83/*
84 * rsh - remote shell
85 */
86int	rfd2;
87
88int family = PF_UNSPEC;
89
90char   *copyargs __P((char **));
91void	sendsig __P((int));
92void	talk __P((int, long, pid_t, int, int));
93void	usage __P((void));
94
95int
96main(argc, argv)
97	int argc;
98	char **argv;
99{
100	struct passwd *pw;
101	struct servent *sp;
102	long omask;
103	int argoff, asrsh, ch, dflag, nflag, one, rem;
104	pid_t pid = 0;
105	uid_t uid;
106	char *args, *host, *p, *user;
107	int timeout = 0;
108#ifdef KERBEROS
109	char *k;
110#endif
111
112	argoff = asrsh = dflag = nflag = 0;
113	one = 1;
114	host = user = NULL;
115
116	/* if called as something other than "rsh", use it as the host name */
117	if ((p = strrchr(argv[0], '/')))
118		++p;
119	else
120		p = argv[0];
121	if (strcmp(p, "rsh"))
122		host = p;
123	else
124		asrsh = 1;
125
126	/* handle "rsh host flags" */
127	if (!host && argc > 2 && argv[1][0] != '-') {
128		host = argv[1];
129		argoff = 1;
130	}
131
132#ifdef KERBEROS
133#ifdef CRYPT
134#define	OPTIONS	"468KLde:k:l:nt:wx"
135#else
136#define	OPTIONS	"468KLde:k:l:nt:w"
137#endif
138#else
139#define	OPTIONS	"468KLde:l:nt:w"
140#endif
141	while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != -1)
142		switch(ch) {
143		case '4':
144			family = PF_INET;
145			break;
146
147		case '6':
148			family = PF_INET6;
149			break;
150
151		case 'K':
152#ifdef KERBEROS
153			use_kerberos = 0;
154#endif
155			break;
156		case 'L':	/* -8Lew are ignored to allow rlogin aliases */
157		case 'e':
158		case 'w':
159		case '8':
160			break;
161		case 'd':
162			dflag = 1;
163			break;
164		case 'l':
165			user = optarg;
166			break;
167#ifdef KERBEROS
168		case 'k':
169			dest_realm = dst_realm_buf;
170			strncpy(dest_realm, optarg, REALM_SZ);
171			break;
172#endif
173		case 'n':
174			nflag = 1;
175			break;
176#ifdef KERBEROS
177#ifdef CRYPT
178		case 'x':
179			doencrypt = 1;
180			break;
181#endif
182#endif
183		case 't':
184			timeout = atoi(optarg);
185			break;
186		case '?':
187		default:
188			usage();
189		}
190	optind += argoff;
191
192	/* if haven't gotten a host yet, do so */
193	if (!host && !(host = argv[optind++]))
194		usage();
195
196	/* if no further arguments, must have been called as rlogin. */
197	if (!argv[optind]) {
198		if (asrsh)
199			*argv = "rlogin";
200		execv(_PATH_RLOGIN, argv);
201		err(1, "can't exec %s", _PATH_RLOGIN);
202	}
203
204	argc -= optind;
205	argv += optind;
206
207	if (!(pw = getpwuid(uid = getuid())))
208		errx(1, "unknown user id");
209	if (!user)
210		user = pw->pw_name;
211
212#ifdef KERBEROS
213#ifdef CRYPT
214	/* -x turns off -n */
215	if (doencrypt)
216		nflag = 0;
217#endif
218#endif
219
220	args = copyargs(argv);
221
222	sp = NULL;
223#ifdef KERBEROS
224	k = auth_getval("auth_list");
225	if (k && !strstr(k, "kerberos"))
226	    use_kerberos = 0;
227	if (use_kerberos) {
228		sp = getservbyname((doencrypt ? "ekshell" : "kshell"), "tcp");
229		if (sp == NULL) {
230			use_kerberos = 0;
231			warnx(
232	"warning, using standard rsh: can't get entry for %s/tcp service",
233			    doencrypt ? "ekshell" : "kshell");
234		}
235	}
236#endif
237	if (sp == NULL)
238		sp = getservbyname("shell", "tcp");
239	if (sp == NULL)
240		errx(1, "shell/tcp: unknown service");
241
242#ifdef KERBEROS
243try_connect:
244	if (use_kerberos) {
245		struct hostent *hp;
246
247		/* fully qualify hostname (needed for krb_realmofhost) */
248		hp = gethostbyname(host);
249		if (hp != NULL && !(host = strdup(hp->h_name)))
250			err(1, NULL);
251
252		rem = KSUCCESS;
253		errno = 0;
254		if (dest_realm == NULL)
255			dest_realm = krb_realmofhost(host);
256
257#ifdef CRYPT
258		if (doencrypt) {
259			rem = krcmd_mutual(&host, sp->s_port, user, args,
260			    &rfd2, dest_realm, &cred, schedule);
261			des_set_key(&cred.session, schedule);
262		} else
263#endif
264			rem = krcmd(&host, sp->s_port, user, args, &rfd2,
265			    dest_realm);
266		if (rem < 0) {
267			use_kerberos = 0;
268			sp = getservbyname("shell", "tcp");
269			if (sp == NULL)
270				errx(1, "shell/tcp: unknown service");
271			if (errno == ECONNREFUSED)
272				warnx(
273		"warning, using standard rsh: remote host doesn't support Kerberos");
274			if (errno == ENOENT)
275				warnx(
276		"warning, using standard rsh: can't provide Kerberos auth data");
277			goto try_connect;
278		}
279	} else {
280		if (doencrypt)
281			errx(1, "the -x flag requires Kerberos authentication");
282		rem = rcmd_af(&host, sp->s_port, pw->pw_name, user, args,
283			      &rfd2, family);
284	}
285#else
286	rem = rcmd_af(&host, sp->s_port, pw->pw_name, user, args, &rfd2,
287		      family);
288#endif
289
290	if (rem < 0)
291		exit(1);
292
293	if (rfd2 < 0)
294		errx(1, "can't establish stderr");
295	if (dflag) {
296		if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one,
297		    sizeof(one)) < 0)
298			warn("setsockopt");
299		if (setsockopt(rfd2, SOL_SOCKET, SO_DEBUG, &one,
300		    sizeof(one)) < 0)
301			warn("setsockopt");
302	}
303
304	(void)setuid(uid);
305	omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGTERM));
306	if (signal(SIGINT, SIG_IGN) != SIG_IGN)
307		(void)signal(SIGINT, sendsig);
308	if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
309		(void)signal(SIGQUIT, sendsig);
310	if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
311		(void)signal(SIGTERM, sendsig);
312
313	if (!nflag) {
314		pid = fork();
315		if (pid < 0)
316			err(1, "fork");
317	}
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(nflag, omask, pid, rem, timeout)
338	int nflag;
339	long omask;
340	pid_t pid;
341	int rem;
342{
343	int cc, wc;
344	fd_set readfrom, ready, rembits;
345	char *bp, buf[BUFSIZ];
346	struct timeval tvtimeout;
347	int nfds, srval;
348
349	if (!nflag && pid == 0) {
350		(void)close(rfd2);
351
352reread:		errno = 0;
353		if ((cc = read(0, buf, sizeof buf)) <= 0)
354			goto done;
355		bp = buf;
356
357rewrite:
358		FD_ZERO(&rembits);
359		FD_SET(rem, &rembits);
360		nfds = rem + 1;
361		if (select(nfds, 0, &rembits, 0, 0) < 0) {
362			if (errno != EINTR)
363				err(1, "select");
364			goto rewrite;
365		}
366		if (!FD_ISSET(rem, &rembits))
367			goto rewrite;
368#ifdef KERBEROS
369#ifdef CRYPT
370		if (doencrypt)
371			wc = des_enc_write(rem, bp, cc, schedule, &cred.session);
372		else
373#endif
374#endif
375			wc = write(rem, bp, cc);
376		if (wc < 0) {
377			if (errno == EWOULDBLOCK)
378				goto rewrite;
379			goto done;
380		}
381		bp += wc;
382		cc -= wc;
383		if (cc == 0)
384			goto reread;
385		goto rewrite;
386done:
387		(void)shutdown(rem, 1);
388		exit(0);
389	}
390
391	tvtimeout.tv_sec = timeout;
392	tvtimeout.tv_usec = 0;
393
394	(void)sigsetmask(omask);
395	FD_ZERO(&readfrom);
396	FD_SET(rfd2, &readfrom);
397	FD_SET(rem, &readfrom);
398	nfds = MAX(rfd2+1, rem+1);
399	do {
400		ready = readfrom;
401		if (timeout) {
402			srval = select(nfds, &ready, 0, 0, &tvtimeout);
403		} else {
404			srval = select(nfds, &ready, 0, 0, 0);
405		}
406
407		if (srval < 0) {
408			if (errno != EINTR)
409				err(1, "select");
410			continue;
411		}
412		if (srval == 0)
413			errx(1, "timeout reached (%d seconds)\n", timeout);
414		if (FD_ISSET(rfd2, &ready)) {
415			errno = 0;
416#ifdef KERBEROS
417#ifdef CRYPT
418			if (doencrypt)
419				cc = des_enc_read(rfd2, buf, sizeof buf, schedule, &cred.session);
420			else
421#endif
422#endif
423				cc = read(rfd2, buf, sizeof buf);
424			if (cc <= 0) {
425				if (errno != EWOULDBLOCK)
426					FD_CLR(rfd2, &readfrom);
427			} else
428				(void)write(2, buf, cc);
429		}
430		if (FD_ISSET(rem, &ready)) {
431			errno = 0;
432#ifdef KERBEROS
433#ifdef CRYPT
434			if (doencrypt)
435				cc = des_enc_read(rem, buf, sizeof buf, schedule, &cred.session);
436			else
437#endif
438#endif
439				cc = read(rem, buf, sizeof buf);
440			if (cc <= 0) {
441				if (errno != EWOULDBLOCK)
442					FD_CLR(rem, &readfrom);
443			} else
444				(void)write(1, buf, cc);
445		}
446	} while (FD_ISSET(rfd2, &readfrom) || FD_ISSET(rem, &readfrom));
447}
448
449void
450sendsig(sig)
451	int sig;
452{
453	char signo;
454
455	signo = sig;
456#ifdef KERBEROS
457#ifdef CRYPT
458	if (doencrypt)
459		(void)des_enc_write(rfd2, &signo, 1, schedule, &cred.session);
460	else
461#endif
462#endif
463		(void)write(rfd2, &signo, 1);
464}
465
466char *
467copyargs(argv)
468	char **argv;
469{
470	int cc;
471	char **ap, *args, *p;
472
473	cc = 0;
474	for (ap = argv; *ap; ++ap)
475		cc += strlen(*ap) + 1;
476	if (!(args = malloc((u_int)cc)))
477		err(1, NULL);
478	for (p = args, ap = argv; *ap; ++ap) {
479		(void)strcpy(p, *ap);
480		for (p = strcpy(p, *ap); *p; ++p);
481		if (ap[1])
482			*p++ = ' ';
483	}
484	return (args);
485}
486
487void
488usage()
489{
490
491	(void)fprintf(stderr,
492	    "usage: rsh [-46] [-nd%s]%s[-l login] [-t timeout] host [command]\n",
493#ifdef KERBEROS
494#ifdef CRYPT
495	    "x", " [-k realm] ");
496#else
497	    "", " [-k realm] ");
498#endif
499#else
500	    "", " ");
501#endif
502	exit(1);
503}
504
505