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rsh.c revision 1.3
      1 /*-
      2  * Copyright (c) 1983, 1990 The Regents of the University of California.
      3  * 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
     35 char copyright[] =
     36 "@(#) Copyright (c) 1983, 1990 The Regents of the University of California.\n\
     37  All rights reserved.\n";
     38 #endif /* not lint */
     39 
     40 #ifndef lint
     41 /*static char sccsid[] = "from: @(#)rsh.c	5.24 (Berkeley) 7/1/91";*/
     42 static char rcsid[] = "$Id: rsh.c,v 1.3 1995/06/27 00:31:00 jtc Exp $";
     43 #endif /* not lint */
     44 
     45 /*
     46  * $Source: /tank/opengrok/rsync2/NetBSD/src/usr.bin/rsh/rsh.c,v $
     47  * $Header: /tank/opengrok/rsync2/NetBSD/src/usr.bin/rsh/rsh.c,v 1.3 1995/06/27 00:31:00 jtc Exp $
     48  */
     49 
     50 #include <sys/types.h>
     51 #include <sys/socket.h>
     52 #include <sys/ioctl.h>
     53 #include <sys/file.h>
     54 
     55 #include <netinet/in.h>
     56 #include <netdb.h>
     57 
     58 #include <pwd.h>
     59 #include <signal.h>
     60 #include <stdio.h>
     61 #include <errno.h>
     62 #include <string.h>
     63 #include <varargs.h>
     64 #include "pathnames.h"
     65 
     66 #ifdef KERBEROS
     67 #include <kerberosIV/des.h>
     68 #include <kerberosIV/krb.h>
     69 
     70 CREDENTIALS cred;
     71 Key_schedule schedule;
     72 int use_kerberos = 1, doencrypt;
     73 char dst_realm_buf[REALM_SZ], *dest_realm;
     74 extern char *krb_realmofhost();
     75 #endif
     76 
     77 /*
     78  * rsh - remote shell
     79  */
     80 extern int errno;
     81 int rfd2;
     82 
     83 main(argc, argv)
     84 	int argc;
     85 	char **argv;
     86 {
     87 	extern char *optarg;
     88 	extern int optind;
     89 	struct passwd *pw;
     90 	struct servent *sp;
     91 	long omask;
     92 	int argoff, asrsh, ch, dflag, nflag, one, pid, rem, uid;
     93 	register char *p;
     94 	char *args, *host, *user, *copyargs();
     95 	void sendsig();
     96 
     97 	argoff = asrsh = dflag = nflag = 0;
     98 	one = 1;
     99 	host = user = NULL;
    100 
    101 	/* if called as something other than "rsh", use it as the host name */
    102 	if (p = rindex(argv[0], '/'))
    103 		++p;
    104 	else
    105 		p = argv[0];
    106 	if (strcmp(p, "rsh"))
    107 		host = p;
    108 	else
    109 		asrsh = 1;
    110 
    111 	/* handle "rsh host flags" */
    112 	if (!host && argc > 2 && argv[1][0] != '-') {
    113 		host = argv[1];
    114 		argoff = 1;
    115 	}
    116 
    117 #ifdef KERBEROS
    118 #ifdef CRYPT
    119 #define	OPTIONS	"8KLdek:l:nwx"
    120 #else
    121 #define	OPTIONS	"8KLdek:l:nw"
    122 #endif
    123 #else
    124 #define	OPTIONS	"8KLdel:nw"
    125 #endif
    126 	while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != EOF)
    127 		switch(ch) {
    128 		case 'K':
    129 #ifdef KERBEROS
    130 			use_kerberos = 0;
    131 #endif
    132 			break;
    133 		case 'L':	/* -8Lew are ignored to allow rlogin aliases */
    134 		case 'e':
    135 		case 'w':
    136 		case '8':
    137 			break;
    138 		case 'd':
    139 			dflag = 1;
    140 			break;
    141 		case 'l':
    142 			user = optarg;
    143 			break;
    144 #ifdef KERBEROS
    145 		case 'k':
    146 			dest_realm = dst_realm_buf;
    147 			strncpy(dest_realm, optarg, REALM_SZ);
    148 			break;
    149 #endif
    150 		case 'n':
    151 			nflag = 1;
    152 			break;
    153 #ifdef KERBEROS
    154 #ifdef CRYPT
    155 		case 'x':
    156 			doencrypt = 1;
    157 			des_set_key(cred.session, schedule);
    158 			break;
    159 #endif
    160 #endif
    161 		case '?':
    162 		default:
    163 			usage();
    164 		}
    165 	optind += argoff;
    166 
    167 	/* if haven't gotten a host yet, do so */
    168 	if (!host && !(host = argv[optind++]))
    169 		usage();
    170 
    171 	/* if no further arguments, must have been called as rlogin. */
    172 	if (!argv[optind]) {
    173 		if (asrsh)
    174 			*argv = "rlogin";
    175 		execv(_PATH_RLOGIN, argv);
    176 		(void)fprintf(stderr, "rsh: can't exec %s.\n", _PATH_RLOGIN);
    177 		exit(1);
    178 	}
    179 
    180 	argc -= optind;
    181 	argv += optind;
    182 
    183 	if (!(pw = getpwuid(uid = getuid()))) {
    184 		(void)fprintf(stderr, "rsh: unknown user id.\n");
    185 		exit(1);
    186 	}
    187 	if (!user)
    188 		user = pw->pw_name;
    189 
    190 #ifdef KERBEROS
    191 #ifdef CRYPT
    192 	/* -x turns off -n */
    193 	if (doencrypt)
    194 		nflag = 0;
    195 #endif
    196 #endif
    197 
    198 	args = copyargs(argv);
    199 
    200 	sp = NULL;
    201 #ifdef KERBEROS
    202 	if (use_kerberos) {
    203 		sp = getservbyname((doencrypt ? "ekshell" : "kshell"), "tcp");
    204 		if (sp == NULL) {
    205 			use_kerberos = 0;
    206 			warning("can't get entry for %s/tcp service",
    207 			    doencrypt ? "ekshell" : "kshell");
    208 		}
    209 	}
    210 #endif
    211 	if (sp == NULL)
    212 		sp = getservbyname("shell", "tcp");
    213 	if (sp == NULL) {
    214 		(void)fprintf(stderr, "rsh: shell/tcp: unknown service.\n");
    215 		exit(1);
    216 	}
    217 
    218 #ifdef KERBEROS
    219 try_connect:
    220 	if (use_kerberos) {
    221 		rem = KSUCCESS;
    222 		errno = 0;
    223 		if (dest_realm == NULL)
    224 			dest_realm = krb_realmofhost(host);
    225 
    226 #ifdef CRYPT
    227 		if (doencrypt)
    228 			rem = krcmd_mutual(&host, sp->s_port, user, args,
    229 			    &rfd2, dest_realm, &cred, schedule);
    230 		else
    231 #endif
    232 			rem = krcmd(&host, sp->s_port, user, args, &rfd2,
    233 			    dest_realm);
    234 		if (rem < 0) {
    235 			use_kerberos = 0;
    236 			sp = getservbyname("shell", "tcp");
    237 			if (sp == NULL) {
    238 				(void)fprintf(stderr,
    239 				    "rsh: unknown service shell/tcp.\n");
    240 				exit(1);
    241 			}
    242 			if (errno == ECONNREFUSED)
    243 				warning("remote host doesn't support Kerberos");
    244 			if (errno == ENOENT)
    245 				warning("can't provide Kerberos auth data");
    246 			goto try_connect;
    247 		}
    248 	} else {
    249 		if (doencrypt) {
    250 			(void)fprintf(stderr,
    251 			    "rsh: the -x flag requires Kerberos authentication.\n");
    252 			exit(1);
    253 		}
    254 		rem = rcmd(&host, sp->s_port, pw->pw_name, user, args, &rfd2);
    255 	}
    256 #else
    257 	rem = rcmd(&host, sp->s_port, pw->pw_name, user, args, &rfd2);
    258 #endif
    259 
    260 	if (rem < 0)
    261 		exit(1);
    262 
    263 	if (rfd2 < 0) {
    264 		(void)fprintf(stderr, "rsh: can't establish stderr.\n");
    265 		exit(1);
    266 	}
    267 	if (dflag) {
    268 		if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one,
    269 		    sizeof(one)) < 0)
    270 			(void)fprintf(stderr, "rsh: setsockopt: %s.\n",
    271 			    strerror(errno));
    272 		if (setsockopt(rfd2, SOL_SOCKET, SO_DEBUG, &one,
    273 		    sizeof(one)) < 0)
    274 			(void)fprintf(stderr, "rsh: setsockopt: %s.\n",
    275 			    strerror(errno));
    276 	}
    277 
    278 	(void)setuid(uid);
    279 	omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGTERM));
    280 	if (signal(SIGINT, SIG_IGN) != SIG_IGN)
    281 		(void)signal(SIGINT, sendsig);
    282 	if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
    283 		(void)signal(SIGQUIT, sendsig);
    284 	if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
    285 		(void)signal(SIGTERM, sendsig);
    286 
    287 	if (!nflag) {
    288 		pid = fork();
    289 		if (pid < 0) {
    290 			(void)fprintf(stderr,
    291 			    "rsh: fork: %s.\n", strerror(errno));
    292 			exit(1);
    293 		}
    294 	}
    295 
    296 #ifdef KERBEROS
    297 #ifdef CRYPT
    298 	if (!doencrypt)
    299 #endif
    300 #endif
    301 	{
    302 		(void)ioctl(rfd2, FIONBIO, &one);
    303 		(void)ioctl(rem, FIONBIO, &one);
    304 	}
    305 
    306 	talk(nflag, omask, pid, rem);
    307 
    308 	if (!nflag)
    309 		(void)kill(pid, SIGKILL);
    310 	exit(0);
    311 }
    312 
    313 talk(nflag, omask, pid, rem)
    314 	int nflag, pid;
    315 	long omask;
    316 	register int rem;
    317 {
    318 	register int cc, wc;
    319 	register char *bp;
    320 	int readfrom, ready, rembits;
    321 	char buf[BUFSIZ];
    322 
    323 	if (!nflag && pid == 0) {
    324 		(void)close(rfd2);
    325 
    326 reread:		errno = 0;
    327 		if ((cc = read(0, buf, sizeof buf)) <= 0)
    328 			goto done;
    329 		bp = buf;
    330 
    331 rewrite:	rembits = 1 << rem;
    332 		if (select(16, 0, &rembits, 0, 0) < 0) {
    333 			if (errno != EINTR) {
    334 				(void)fprintf(stderr,
    335 				    "rsh: select: %s.\n", strerror(errno));
    336 				exit(1);
    337 			}
    338 			goto rewrite;
    339 		}
    340 		if ((rembits & (1 << rem)) == 0)
    341 			goto rewrite;
    342 #ifdef KERBEROS
    343 #ifdef CRYPT
    344 		if (doencrypt)
    345 			wc = des_write(rem, bp, cc);
    346 		else
    347 #endif
    348 #endif
    349 			wc = write(rem, bp, cc);
    350 		if (wc < 0) {
    351 			if (errno == EWOULDBLOCK)
    352 				goto rewrite;
    353 			goto done;
    354 		}
    355 		bp += wc;
    356 		cc -= wc;
    357 		if (cc == 0)
    358 			goto reread;
    359 		goto rewrite;
    360 done:
    361 		(void)shutdown(rem, 1);
    362 		exit(0);
    363 	}
    364 
    365 	(void)sigsetmask(omask);
    366 	readfrom = (1 << rfd2) | (1 << rem);
    367 	do {
    368 		ready = readfrom;
    369 		if (select(16, &ready, 0, 0, 0) < 0) {
    370 			if (errno != EINTR) {
    371 				(void)fprintf(stderr,
    372 				    "rsh: select: %s.\n", strerror(errno));
    373 				exit(1);
    374 			}
    375 			continue;
    376 		}
    377 		if (ready & (1 << rfd2)) {
    378 			errno = 0;
    379 #ifdef KERBEROS
    380 #ifdef CRYPT
    381 			if (doencrypt)
    382 				cc = des_read(rfd2, buf, sizeof buf);
    383 			else
    384 #endif
    385 #endif
    386 				cc = read(rfd2, buf, sizeof buf);
    387 			if (cc <= 0) {
    388 				if (errno != EWOULDBLOCK)
    389 					readfrom &= ~(1 << rfd2);
    390 			} else
    391 				(void)write(2, buf, cc);
    392 		}
    393 		if (ready & (1 << rem)) {
    394 			errno = 0;
    395 #ifdef KERBEROS
    396 #ifdef CRYPT
    397 			if (doencrypt)
    398 				cc = des_read(rem, buf, sizeof buf);
    399 			else
    400 #endif
    401 #endif
    402 				cc = read(rem, buf, sizeof buf);
    403 			if (cc <= 0) {
    404 				if (errno != EWOULDBLOCK)
    405 					readfrom &= ~(1 << rem);
    406 			} else
    407 				(void)write(1, buf, cc);
    408 		}
    409 	} while (readfrom);
    410 }
    411 
    412 void
    413 sendsig(signo)
    414 	char signo;
    415 {
    416 #ifdef KERBEROS
    417 #ifdef CRYPT
    418 	if (doencrypt)
    419 		(void)des_write(rfd2, &signo, 1);
    420 	else
    421 #endif
    422 #endif
    423 		(void)write(rfd2, &signo, 1);
    424 }
    425 
    426 #ifdef KERBEROS
    427 /* VARARGS */
    428 warning(va_alist)
    429 va_dcl
    430 {
    431 	va_list ap;
    432 	char *fmt;
    433 
    434 	(void)fprintf(stderr, "rsh: warning, using standard rsh: ");
    435 	va_start(ap);
    436 	fmt = va_arg(ap, char *);
    437 	vfprintf(stderr, fmt, ap);
    438 	va_end(ap);
    439 	(void)fprintf(stderr, ".\n");
    440 }
    441 #endif
    442 
    443 char *
    444 copyargs(argv)
    445 	char **argv;
    446 {
    447 	register int cc;
    448 	register char **ap, *p;
    449 	char *args, *malloc();
    450 
    451 	cc = 0;
    452 	for (ap = argv; *ap; ++ap)
    453 		cc += strlen(*ap) + 1;
    454 	if (!(args = malloc((u_int)cc))) {
    455 		(void)fprintf(stderr, "rsh: %s.\n", strerror(ENOMEM));
    456 		exit(1);
    457 	}
    458 	for (p = args, ap = argv; *ap; ++ap) {
    459 		(void)strcpy(p, *ap);
    460 		for (p = strcpy(p, *ap); *p; ++p);
    461 		if (ap[1])
    462 			*p++ = ' ';
    463 	}
    464 	return(args);
    465 }
    466 
    467 usage()
    468 {
    469 	(void)fprintf(stderr,
    470 	    "usage: rsh [-nd%s]%s[-l login] host [command]\n",
    471 #ifdef KERBEROS
    472 #ifdef CRYPT
    473 	    "x", " [-k realm] ");
    474 #else
    475 	    "", " [-k realm] ");
    476 #endif
    477 #else
    478 	    "", " ");
    479 #endif
    480 	exit(1);
    481 }
    482