rsh.c revision 1.9
1 /* $NetBSD: rsh.c,v 1.9 1997/06/05 16:10:50 mrg Exp $ */ 2 3 /*- 4 * Copyright (c) 1983, 1990, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #ifndef lint 37 static char copyright[] = 38 "@(#) Copyright (c) 1983, 1990, 1993, 1994\n\ 39 The Regents of the University of California. All rights reserved.\n"; 40 #endif /* not lint */ 41 42 #ifndef lint 43 /*static char sccsid[] = "from: @(#)rsh.c 8.4 (Berkeley) 4/29/95";*/ 44 static char rcsid[] = "$NetBSD: rsh.c,v 1.9 1997/06/05 16:10:50 mrg Exp $"; 45 #endif /* not lint */ 46 47 #include <sys/types.h> 48 #include <sys/socket.h> 49 #include <sys/ioctl.h> 50 #include <sys/file.h> 51 #include <poll.h> 52 53 #include <netinet/in.h> 54 #include <netdb.h> 55 56 #include <err.h> 57 #include <errno.h> 58 #include <pwd.h> 59 #include <signal.h> 60 #include <stdio.h> 61 #include <stdlib.h> 62 #include <string.h> 63 #include <unistd.h> 64 #include <varargs.h> 65 66 #include "pathnames.h" 67 68 #ifdef KERBEROS 69 #include <kerberosIV/des.h> 70 #include <kerberosIV/krb.h> 71 72 CREDENTIALS cred; 73 Key_schedule schedule; 74 int use_kerberos = 1, doencrypt; 75 char dst_realm_buf[REALM_SZ], *dest_realm; 76 extern char *krb_realmofhost(); 77 #endif 78 79 /* 80 * rsh - remote shell 81 */ 82 extern char *__progname; /* XXX */ 83 int rfd2; 84 85 char *copyargs __P((char **)); 86 void sendsig __P((int)); 87 void talk __P((int, long, pid_t, int)); 88 void usage __P((void)); 89 void warning __P(()); 90 91 int 92 main(argc, argv) 93 int argc; 94 char **argv; 95 { 96 struct passwd *pw; 97 struct servent *sp; 98 long omask; 99 #ifdef IN_RCMD 100 char *locuser = 0, *loop; 101 #endif /* IN_RCMD */ 102 int argoff, asrsh, ch, dflag, nflag, one, rem; 103 pid_t pid; 104 uid_t uid; 105 char *args, *host, *p, *user, *name; 106 107 argoff = asrsh = dflag = nflag = 0; 108 one = 1; 109 host = user = NULL; 110 111 #ifndef IN_RCMD 112 /* 113 * If called as something other than "rsh" use it as the host name, 114 * only for rsh. 115 */ 116 p = __progname; 117 if (strcmp(p, "rsh") == 0) 118 asrsh = 1; 119 else 120 host = p; 121 #endif /* IN_RCMD */ 122 123 /* handle "rsh host flags" */ 124 if (!host && argc > 2 && argv[1][0] != '-') { 125 host = argv[1]; 126 argoff = 1; 127 } 128 129 #ifdef IN_RCMD 130 if ((loop = getenv("RCMD_LOOP")) && strcmp(loop, "YES") == 0) 131 warnx("rcmd appears to be looping!"); 132 133 putenv("RCMD_LOOP=YES"); 134 135 # ifdef KERBEROS 136 # ifdef CRYPT 137 # define OPTIONS "8KLdek:l:nu:wx" 138 # else 139 # define OPTIONS "8KLdek:l:nu:w" 140 # endif 141 # else 142 # define OPTIONS "8KLdel:nu:w" 143 # endif 144 145 #else /* IN_RCMD */ 146 147 # ifdef KERBEROS 148 # ifdef CRYPT 149 # define OPTIONS "8KLdek:l:nwx" 150 # else 151 # define OPTIONS "8KLdek:l:nw" 152 # endif 153 # else 154 # define OPTIONS "8KLdel:nw" 155 # endif 156 157 #endif /* IN_RCMD */ 158 159 if (!(pw = getpwuid(uid = getuid()))) 160 errx(1, "unknown user id"); 161 162 if ((name = strdup(pw->pw_name)) == NULL) 163 err(1, "malloc"); 164 while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != EOF) 165 switch(ch) { 166 case 'K': 167 #ifdef KERBEROS 168 use_kerberos = 0; 169 #endif 170 break; 171 case 'L': /* -8Lew are ignored to allow rlogin aliases */ 172 case 'e': 173 case 'w': 174 case '8': 175 break; 176 case 'd': 177 dflag = 1; 178 break; 179 case 'l': 180 user = optarg; 181 break; 182 #ifdef KERBEROS 183 case 'k': 184 dest_realm = dst_realm_buf; 185 strncpy(dest_realm, optarg, REALM_SZ); 186 break; 187 #endif 188 case 'n': 189 nflag = 1; 190 break; 191 #ifdef IN_RCMD 192 case 'u': 193 if (getuid() != 0 && optarg && name && 194 strcmp(name, optarg) != 0) 195 errx(1,"only super user can use the -u option"); 196 locuser = optarg; 197 break; 198 #endif /* IN_RCMD */ 199 #ifdef KERBEROS 200 #ifdef CRYPT 201 case 'x': 202 doencrypt = 1; 203 des_set_key(cred.session, schedule); 204 break; 205 #endif 206 #endif 207 case '?': 208 default: 209 usage(); 210 } 211 optind += argoff; 212 213 /* if haven't gotten a host yet, do so */ 214 if (!host && !(host = argv[optind++])) 215 usage(); 216 217 /* if no further arguments, must have been called as rlogin. */ 218 if (!argv[optind]) { 219 #ifdef IN_RCMD 220 usage(); 221 #else 222 if (asrsh) 223 *argv = "rlogin"; 224 execv(_PATH_RLOGIN, argv); 225 err(1, "can't exec %s", _PATH_RLOGIN); 226 #endif 227 } 228 229 argc -= optind; 230 argv += optind; 231 232 /* Accept user1@host format, though "-l user2" overrides user1 */ 233 p = strchr(host, '@'); 234 if (p) { 235 *p = '\0'; 236 if (!user && p > host) 237 user = host; 238 host = p + 1; 239 if (*host == '\0') 240 usage(); 241 } 242 if (!user) 243 user = name; 244 245 #ifdef KERBEROS 246 #ifdef CRYPT 247 /* -x turns off -n */ 248 if (doencrypt) 249 nflag = 0; 250 #endif 251 #endif 252 253 args = copyargs(argv); 254 255 sp = NULL; 256 #ifdef KERBEROS 257 if (use_kerberos) { 258 sp = getservbyname((doencrypt ? "ekshell" : "kshell"), "tcp"); 259 if (sp == NULL) { 260 use_kerberos = 0; 261 warning("can't get entry for %s/tcp service", 262 doencrypt ? "ekshell" : "kshell"); 263 } 264 } 265 #endif 266 if (sp == NULL) 267 sp = getservbyname("shell", "tcp"); 268 if (sp == NULL) 269 errx(1, "shell/tcp: unknown service"); 270 271 #ifdef KERBEROS 272 try_connect: 273 if (use_kerberos) { 274 #if 1 275 struct hostent *hp; 276 277 /* fully qualify hostname (needed for krb_realmofhost) */ 278 hp = gethostbyname(host); 279 if (hp != NULL && !(host = strdup(hp->h_name))) 280 err(1, NULL); 281 #endif 282 283 rem = KSUCCESS; 284 errno = 0; 285 if (dest_realm == NULL) 286 dest_realm = krb_realmofhost(host); 287 288 #ifdef CRYPT 289 if (doencrypt) 290 rem = krcmd_mutual(&host, sp->s_port, user, args, 291 &rfd2, dest_realm, &cred, schedule); 292 else 293 #endif 294 rem = krcmd(&host, sp->s_port, user, args, &rfd2, 295 dest_realm); 296 if (rem < 0) { 297 use_kerberos = 0; 298 sp = getservbyname("shell", "tcp"); 299 if (sp == NULL) 300 errx(1, "shell/tcp: unknown service"); 301 if (errno == ECONNREFUSED) 302 warning("remote host doesn't support Kerberos"); 303 if (errno == ENOENT) 304 warning("can't provide Kerberos auth data"); 305 goto try_connect; 306 } 307 } else { 308 if (doencrypt) 309 errx(1, "the -x flag requires Kerberos authentication."); 310 #ifdef IN_RCMD 311 rem = orcmd(&host, sp->s_port, locuser ? locuser : 312 #else 313 rem = rcmd(&host, sp->s_port, 314 #endif 315 name, 316 user, args, &rfd2); 317 } 318 #else /* KERBEROS */ 319 320 #ifdef IN_RCMD 321 rem = orcmd(&host, sp->s_port, locuser ? locuser : 322 #else 323 rem = rcmd(&host, sp->s_port, 324 #endif 325 name, user, args, &rfd2); 326 #endif /* KERBEROS */ 327 (void)free(name); 328 329 if (rem < 0) 330 exit(1); 331 332 if (rfd2 < 0) 333 errx(1, "can't establish stderr"); 334 if (dflag) { 335 if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one, 336 sizeof(one)) < 0) 337 warn("setsockopt remote"); 338 if (setsockopt(rfd2, SOL_SOCKET, SO_DEBUG, &one, 339 sizeof(one)) < 0) 340 warn("setsockopt stderr"); 341 } 342 343 (void)setuid(uid); 344 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGTERM)); 345 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 346 (void)signal(SIGINT, sendsig); 347 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 348 (void)signal(SIGQUIT, sendsig); 349 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 350 (void)signal(SIGTERM, sendsig); 351 352 if (!nflag) { 353 pid = fork(); 354 if (pid < 0) 355 err(1, "fork"); 356 } 357 358 #ifdef KERBEROS 359 #ifdef CRYPT 360 if (!doencrypt) 361 #endif 362 #endif 363 { 364 (void)ioctl(rfd2, FIONBIO, &one); 365 (void)ioctl(rem, FIONBIO, &one); 366 } 367 368 talk(nflag, omask, pid, rem); 369 370 if (!nflag) 371 (void)kill(pid, SIGKILL); 372 exit(0); 373 } 374 375 void 376 talk(nflag, omask, pid, rem) 377 int nflag; 378 long omask; 379 pid_t pid; 380 int rem; 381 { 382 int cc, wc, nfds; 383 struct pollfd fds[2], *fdp = &fds[0]; 384 char *bp, buf[BUFSIZ]; 385 386 if (!nflag && pid == 0) { 387 (void)close(rfd2); 388 389 reread: errno = 0; 390 if ((cc = read(0, buf, sizeof buf)) <= 0) 391 goto done; 392 bp = buf; 393 394 rewrite: fdp->events = POLLOUT; 395 fdp->fd = rem; 396 if (poll(fdp, 1, 0) < 0) { 397 if (errno != EINTR) 398 err(1, "poll"); 399 goto rewrite; 400 } 401 if ((fdp->revents & POLLOUT) == 0) 402 goto rewrite; 403 #ifdef KERBEROS 404 #ifdef CRYPT 405 if (doencrypt) 406 wc = des_write(rem, bp, cc); 407 else 408 #endif 409 #endif 410 wc = write(rem, bp, cc); 411 if (wc < 0) { 412 if (errno == EWOULDBLOCK) 413 goto rewrite; 414 goto done; 415 } 416 bp += wc; 417 cc -= wc; 418 if (cc == 0) 419 goto reread; 420 goto rewrite; 421 done: 422 (void)shutdown(rem, 1); 423 exit(0); 424 } 425 426 (void)sigsetmask(omask); 427 fds[0].events = fds[1].events = POLLIN; 428 fds[0].fd = rfd2; 429 fds[1].fd = rem; 430 fdp = &fds[0]; 431 nfds = 2; 432 do { 433 if (poll(fdp, nfds, 0) < 0) { 434 if (errno != EINTR) 435 err(1, "poll"); 436 continue; 437 } 438 if (fds[0].events == POLLIN && (fds[0].revents & POLLIN)) { 439 errno = 0; 440 #ifdef KERBEROS 441 #ifdef CRYPT 442 if (doencrypt) 443 cc = des_read(rfd2, buf, sizeof buf); 444 else 445 #endif 446 #endif 447 cc = read(rfd2, buf, sizeof buf); 448 if (cc <= 0) { 449 if (errno != EWOULDBLOCK) { 450 nfds--; 451 fds[0].events = 0; 452 fdp = &fds[1]; 453 } 454 } else 455 (void)write(2, buf, cc); 456 } 457 if (fds[1].events == POLLIN && (fds[1].revents & POLLIN)) { 458 errno = 0; 459 #ifdef KERBEROS 460 #ifdef CRYPT 461 if (doencrypt) 462 cc = des_read(rem, buf, sizeof buf); 463 else 464 #endif 465 #endif 466 cc = read(rem, buf, sizeof buf); 467 if (cc <= 0) { 468 if (errno != EWOULDBLOCK) { 469 nfds--; 470 fds[1].events = 0; 471 } 472 } else 473 (void)write(1, buf, cc); 474 } 475 } while (nfds); 476 } 477 478 void 479 sendsig(sig) 480 int sig; 481 { 482 char signo; 483 484 signo = sig; 485 #ifdef KERBEROS 486 #ifdef CRYPT 487 if (doencrypt) 488 (void)des_write(rfd2, &signo, 1); 489 else 490 #endif 491 #endif 492 (void)write(rfd2, &signo, 1); 493 } 494 495 #ifdef KERBEROS 496 /* VARARGS */ 497 void 498 warning(va_alist) 499 va_dcl 500 { 501 va_list ap; 502 char *fmt; 503 504 (void)fprintf(stderr, "rsh: warning, using standard rsh: "); 505 va_start(ap); 506 fmt = va_arg(ap, char *); 507 vfprintf(stderr, fmt, ap); 508 va_end(ap); 509 (void)fprintf(stderr, ".\n"); 510 } 511 #endif 512 513 char * 514 copyargs(argv) 515 char **argv; 516 { 517 int cc; 518 char **ap, *args, *p; 519 520 cc = 0; 521 for (ap = argv; *ap; ++ap) 522 cc += strlen(*ap) + 1; 523 if (!(args = malloc((u_int)cc))) 524 errx(1, "%s", strerror(ENOMEM)); 525 for (p = args, *p = '\0', ap = argv; *ap; ++ap) { 526 (void)strcpy(p, *ap); 527 p += strlen(p); 528 if (ap[1]) 529 *p++ = ' '; 530 } 531 *p = '\0'; 532 return (args); 533 } 534 535 void 536 usage() 537 { 538 539 (void)fprintf(stderr, 540 "usage: %s [-nd%s]%s[-l login]%s [login@]host %s\n", __progname, 541 #ifdef KERBEROS 542 #ifdef CRYPT 543 "x", " [-k realm] ", 544 #else 545 "", " [-k realm] ", 546 #endif 547 #else 548 "", " ", 549 #endif 550 #ifdef IN_RCMD 551 " [-u locuser]", "command" 552 #else 553 "", "[command]" 554 #endif 555 ); 556 exit(1); 557 } 558
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