1 /* $NetBSD: rsh.c,v 1.17 2003/04/07 01:46:41 hubertf 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 #include <sys/cdefs.h> 37 #ifndef lint 38 __COPYRIGHT("@(#) 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 #if 0 44 static char sccsid[] = "@(#)rsh.c 8.4 (Berkeley) 4/29/95"; 45 #else 46 __RCSID("$NetBSD: rsh.c,v 1.17 2003/04/07 01:46:41 hubertf Exp $"); 47 #endif 48 #endif /* not lint */ 49 50 #include <sys/types.h> 51 #include <sys/socket.h> 52 #include <sys/ioctl.h> 53 #include <sys/file.h> 54 #include <poll.h> 55 56 #include <netinet/in.h> 57 #include <netdb.h> 58 59 #include <err.h> 60 #include <errno.h> 61 #include <pwd.h> 62 #include <signal.h> 63 #include <stdarg.h> 64 #include <stdio.h> 65 #include <stdlib.h> 66 #include <string.h> 67 #include <unistd.h> 68 69 #include "pathnames.h" 70 71 #ifdef KERBEROS 72 #include <kerberosIV/des.h> 73 #include <kerberosIV/krb.h> 74 75 CREDENTIALS cred; 76 Key_schedule schedule; 77 int use_kerberos = 1, doencrypt; 78 char dst_realm_buf[REALM_SZ], *dest_realm; 79 80 void warning(const char *, ...); 81 #endif 82 83 /* 84 * rsh - remote shell 85 */ 86 int remerr; 87 88 static int sigs[] = { SIGINT, SIGTERM, SIGQUIT }; 89 90 char *copyargs(char **); 91 void sendsig(int); 92 int checkfd(struct pollfd *, int); 93 void talk(int, sigset_t *, pid_t, int); 94 void usage(void); 95 int main(int, char **); 96 #ifdef IN_RCMD 97 int orcmd(char **, int, const char *, 98 const char *, const char *, int *); 99 int orcmd_af(char **, int, const char *, 100 const char *, const char *, int *, int); 101 #endif 102 103 int 104 main(int argc, char **argv) 105 { 106 struct passwd *pw; 107 struct servent *sp; 108 sigset_t oset, nset; 109 110 #ifdef IN_RCMD 111 char *locuser = 0, *loop; 112 #endif /* IN_RCMD */ 113 int argoff, asrsh, ch, dflag, nflag, one, rem, i; 114 pid_t pid; 115 uid_t uid; 116 char *args, *host, *p, *user, *name; 117 char *service=NULL; 118 119 argoff = asrsh = dflag = nflag = 0; 120 one = 1; 121 host = user = NULL; 122 sp = NULL; 123 124 #ifndef IN_RCMD 125 /* 126 * If called as something other than "rsh" use it as the host name, 127 * only for rsh. 128 */ 129 if (strcmp(getprogname(), "rsh") == 0) 130 asrsh = 1; 131 else { 132 host = strdup(getprogname()); 133 if (host == NULL) 134 err(1, NULL); 135 } 136 #endif /* IN_RCMD */ 137 138 /* handle "rsh host flags" */ 139 if (!host && argc > 2 && argv[1][0] != '-') { 140 host = argv[1]; 141 argoff = 1; 142 } 143 144 #ifdef IN_RCMD 145 if ((loop = getenv("RCMD_LOOP")) && strcmp(loop, "YES") == 0) 146 warnx("rcmd appears to be looping!"); 147 148 putenv("RCMD_LOOP=YES"); 149 150 # ifdef KERBEROS 151 # ifdef CRYPT 152 # define OPTIONS "8KLdek:l:np:u:wx" 153 # else 154 # define OPTIONS "8KLdek:l:np:u:w" 155 # endif 156 # else 157 # define OPTIONS "8KLdel:np:u:w" 158 # endif 159 160 #else /* IN_RCMD */ 161 162 # ifdef KERBEROS 163 # ifdef CRYPT 164 # define OPTIONS "8KLdek:l:np:wx" 165 # else 166 # define OPTIONS "8KLdek:l:np:w" 167 # endif 168 # else 169 # define OPTIONS "8KLdel:np:w" 170 # endif 171 172 #endif /* IN_RCMD */ 173 174 if (!(pw = getpwuid(uid = getuid()))) 175 errx(1, "unknown user id"); 176 177 if ((name = strdup(pw->pw_name)) == NULL) 178 err(1, "malloc"); 179 while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != -1) 180 switch(ch) { 181 case 'K': 182 #ifdef KERBEROS 183 use_kerberos = 0; 184 #endif 185 break; 186 case 'L': /* -8Lew are ignored to allow rlogin aliases */ 187 case 'e': 188 case 'w': 189 case '8': 190 break; 191 case 'd': 192 dflag = 1; 193 break; 194 case 'l': 195 user = optarg; 196 break; 197 #ifdef KERBEROS 198 case 'k': 199 strlcpy(dest_realm_buf, optarg, sizeof(dest_realm_buf)); 200 dest_realm = dst_realm_buf; 201 break; 202 #endif 203 case 'n': 204 nflag = 1; 205 break; 206 case 'p': 207 service = optarg; 208 sp = getservbyname(service, "tcp"); 209 if (sp == NULL) { /* number given, no name */ 210 sp = malloc(sizeof(*sp)); 211 memset(sp, 0, sizeof(*sp)); 212 sp->s_name = service; 213 sp->s_port = atoi(service); 214 if (sp->s_port <= 0 || sp->s_port > IPPORT_ANONMAX) 215 errx(1,"port must be between 1 and %d", IPPORT_ANONMAX); 216 } 217 break; 218 #ifdef IN_RCMD 219 case 'u': 220 if (getuid() != 0 && optarg && name && 221 strcmp(name, optarg) != 0) 222 errx(1,"only super user can use the -u option"); 223 locuser = optarg; 224 break; 225 #endif /* IN_RCMD */ 226 #ifdef KERBEROS 227 #ifdef CRYPT 228 case 'x': 229 doencrypt = 1; 230 des_set_key((des_cblock *) cred.session, schedule); 231 break; 232 #endif 233 #endif 234 case '?': 235 default: 236 usage(); 237 } 238 optind += argoff; 239 240 /* if haven't gotten a host yet, do so */ 241 if (!host && !(host = argv[optind++])) 242 usage(); 243 244 /* if no further arguments, must have been called as rlogin. */ 245 if (!argv[optind]) { 246 #ifdef IN_RCMD 247 usage(); 248 #else 249 if (asrsh) 250 *argv = "rlogin"; 251 execv(_PATH_RLOGIN, argv); 252 err(1, "can't exec %s", _PATH_RLOGIN); 253 #endif 254 } 255 256 argc -= optind; 257 argv += optind; 258 259 /* Accept user1@host format, though "-l user2" overrides user1 */ 260 p = strchr(host, '@'); 261 if (p) { 262 *p = '\0'; 263 if (!user && p > host) 264 user = host; 265 host = p + 1; 266 if (*host == '\0') 267 usage(); 268 } 269 if (!user) 270 user = name; 271 272 #ifdef KERBEROS 273 #ifdef CRYPT 274 /* -x turns off -n */ 275 if (doencrypt) 276 nflag = 0; 277 #endif 278 #endif 279 280 args = copyargs(argv); 281 282 #ifdef KERBEROS 283 if (use_kerberos) { 284 if (sp == NULL) { 285 sp = getservbyname((doencrypt ? "ekshell" : "kshell"), "tcp"); 286 } 287 if (sp == NULL) { 288 use_kerberos = 0; 289 warning("can't get entry for %s/tcp service", 290 doencrypt ? "ekshell" : "kshell"); 291 } 292 } 293 #endif 294 if (sp == NULL) 295 sp = getservbyname("shell", "tcp"); 296 if (sp == NULL) 297 errx(1, "shell/tcp: unknown service"); 298 299 #ifdef KERBEROS 300 try_connect: 301 if (use_kerberos) { 302 #if 1 303 struct hostent *hp; 304 305 /* fully qualify hostname (needed for krb_realmofhost) */ 306 hp = gethostbyname(host); 307 if (hp != NULL && !(host = strdup(hp->h_name))) 308 err(1, "strdup"); 309 #endif 310 311 rem = KSUCCESS; 312 errno = 0; 313 if (dest_realm == NULL) 314 dest_realm = krb_realmofhost(host); 315 316 #ifdef CRYPT 317 if (doencrypt) 318 rem = krcmd_mutual(&host, sp->s_port, user, args, 319 &remerr, dest_realm, &cred, schedule); 320 else 321 #endif 322 rem = krcmd(&host, sp->s_port, user, args, &remerr, 323 dest_realm); 324 if (rem < 0) { 325 use_kerberos = 0; 326 sp = getservbyname("shell", "tcp"); 327 if (sp == NULL) 328 errx(1, "shell/tcp: unknown service"); 329 if (errno == ECONNREFUSED) 330 warning("remote host doesn't support Kerberos"); 331 if (errno == ENOENT) 332 warning("can't provide Kerberos auth data"); 333 goto try_connect; 334 } 335 } else { 336 if (doencrypt) 337 errx(1, "the -x flag requires Kerberos authentication."); 338 #ifdef IN_RCMD 339 rem = orcmd_af(&host, sp->s_port, locuser ? locuser : 340 #else 341 rem = rcmd_af(&host, sp->s_port, 342 #endif 343 name, 344 user, args, &remerr, PF_UNSPEC); 345 } 346 #else /* KERBEROS */ 347 348 #ifdef IN_RCMD 349 rem = orcmd_af(&host, sp->s_port, locuser ? locuser : 350 #else 351 rem = rcmd_af(&host, sp->s_port, 352 #endif 353 name, user, args, &remerr, PF_UNSPEC); 354 #endif /* KERBEROS */ 355 (void)free(name); 356 357 if (rem < 0) 358 exit(1); 359 360 if (remerr < 0) 361 errx(1, "can't establish stderr"); 362 if (dflag) { 363 if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one, 364 sizeof(one)) < 0) 365 warn("setsockopt remote"); 366 if (setsockopt(remerr, SOL_SOCKET, SO_DEBUG, &one, 367 sizeof(one)) < 0) 368 warn("setsockopt stderr"); 369 } 370 371 (void) setuid(uid); 372 373 (void) sigemptyset(&nset); 374 for (i = 0; i < sizeof(sigs) / sizeof(sigs[0]); i++) 375 (void) sigaddset(&nset, sigs[i]); 376 377 (void) sigprocmask(SIG_BLOCK, &nset, &oset); 378 379 for (i = 0; i < sizeof(sigs) / sizeof(sigs[0]); i++) { 380 struct sigaction sa; 381 382 if (sa.sa_handler != SIG_IGN) { 383 sa.sa_handler = sendsig; 384 (void) sigaction(sigs[i], &sa, NULL); 385 } 386 } 387 388 if (!nflag) { 389 pid = fork(); 390 if (pid < 0) 391 err(1, "fork"); 392 } 393 else 394 pid = -1; 395 396 #if defined(KERBEROS) && defined(CRYPT) 397 if (!doencrypt) 398 #endif 399 { 400 (void)ioctl(remerr, FIONBIO, &one); 401 (void)ioctl(rem, FIONBIO, &one); 402 } 403 404 talk(nflag, &oset, pid, rem); 405 406 if (!nflag) 407 (void)kill(pid, SIGKILL); 408 exit(0); 409 } 410 411 int 412 checkfd(struct pollfd *fdp, int outfd) 413 { 414 int nr, nw; 415 char buf[BUFSIZ]; 416 417 if (fdp->revents & (POLLNVAL|POLLERR|POLLHUP)) 418 return -1; 419 420 if ((fdp->revents & POLLIN) == 0) 421 return 0; 422 423 errno = 0; 424 #if defined(KERBEROS) && defined(CRYPT) 425 if (doencrypt) 426 nr = des_read(fdp->fd, buf, sizeof buf); 427 else 428 #endif 429 nr = read(fdp->fd, buf, sizeof buf); 430 431 if (nr <= 0) { 432 if (errno != EAGAIN) 433 return -1; 434 else 435 return 0; 436 } 437 else { 438 char *bc = buf; 439 while (nr) { 440 if ((nw = write(outfd, bc, nr)) <= 0) 441 return -1; 442 nr -= nw; 443 bc += nw; 444 } 445 return 0; 446 } 447 } 448 449 void 450 talk(int nflag, sigset_t *oset, __pid_t pid, int rem) 451 { 452 int nr, nw, nfds; 453 struct pollfd fds[2], *fdp = &fds[0]; 454 char *bp, buf[BUFSIZ]; 455 456 457 if (!nflag && pid == 0) { 458 (void)close(remerr); 459 460 fdp->events = POLLOUT|POLLNVAL|POLLERR|POLLHUP; 461 fdp->fd = rem; 462 nr = 0; 463 bp = buf; 464 465 for (;;) { 466 errno = 0; 467 468 if (nr == 0) { 469 if ((nr = read(0, buf, sizeof buf)) == 0) 470 goto done; 471 if (nr == -1) { 472 if (errno == EIO) 473 goto done; 474 if (errno == EINTR) 475 continue; 476 err(1, "read"); 477 } 478 bp = buf; 479 } 480 481 rewrite: if (poll(fdp, 1, INFTIM) == -1) { 482 if (errno != EINTR) 483 err(1, "poll"); 484 goto rewrite; 485 } 486 487 if (fdp->revents & (POLLNVAL|POLLERR|POLLHUP)) 488 err(1, "poll"); 489 490 if ((fdp->revents & POLLOUT) == 0) 491 goto rewrite; 492 493 #if defined(KERBEROS) && defined(CRYPT) 494 if (doencrypt) 495 nw = des_write(rem, bp, nr); 496 else 497 #endif 498 nw = write(rem, bp, nr); 499 500 if (nw < 0) { 501 if (errno == EAGAIN) 502 continue; 503 err(1, "write"); 504 } 505 bp += nw; 506 nr -= nw; 507 } 508 done: 509 (void)shutdown(rem, 1); 510 exit(0); 511 } 512 513 (void) sigprocmask(SIG_SETMASK, oset, NULL); 514 fds[0].events = fds[1].events = POLLIN|POLLNVAL|POLLERR|POLLHUP; 515 fds[0].fd = remerr; 516 fds[1].fd = rem; 517 fdp = &fds[0]; 518 nfds = 2; 519 do { 520 if (poll(fdp, nfds, INFTIM) == -1) { 521 if (errno != EINTR) 522 err(1, "poll"); 523 continue; 524 } 525 if (fds[0].events != 0 && checkfd(&fds[0], 2) == -1) { 526 nfds--; 527 fds[0].events = 0; 528 fdp = &fds[1]; 529 } 530 if (fds[1].events != 0 && checkfd(&fds[1], 1) == -1) { 531 nfds--; 532 fds[1].events = 0; 533 } 534 } 535 while (nfds); 536 } 537 538 void 539 sendsig(int sig) 540 { 541 char signo; 542 543 signo = sig; 544 #ifdef KERBEROS 545 #ifdef CRYPT 546 if (doencrypt) 547 (void)des_write(remerr, &signo, 1); 548 else 549 #endif 550 #endif 551 (void)write(remerr, &signo, 1); 552 } 553 554 #ifdef KERBEROS 555 /* VARARGS */ 556 void 557 warning(const char *fmt, ...) 558 { 559 va_list ap; 560 561 va_start(ap, fmt); 562 (void) fprintf(stderr, "%s: warning, using standard rsh: ", 563 getprogname()); 564 (void) vfprintf(stderr, fmt, ap); 565 va_end(ap); 566 (void) fprintf(stderr, ".\n"); 567 } 568 #endif 569 570 char * 571 copyargs(char **argv) 572 { 573 int cc; 574 char **ap, *args, *p; 575 576 cc = 0; 577 for (ap = argv; *ap; ++ap) 578 cc += strlen(*ap) + 1; 579 if (!(args = malloc((u_int)cc))) 580 err(1, "malloc"); 581 for (p = args, *p = '\0', ap = argv; *ap; ++ap) { 582 (void)strcpy(p, *ap); 583 p += strlen(p); 584 if (ap[1]) 585 *p++ = ' '; 586 } 587 *p = '\0'; 588 return (args); 589 } 590 591 void 592 usage(void) 593 { 594 595 (void)fprintf(stderr, 596 "usage: %s [-nd%s]%s[-l login] [-p port]%s [login@]host %s\n", getprogname(), 597 #ifdef KERBEROS 598 #ifdef CRYPT 599 "x", " [-k realm] ", 600 #else 601 "", " [-k realm] ", 602 #endif 603 #else 604 "", " ", 605 #endif 606 #ifdef IN_RCMD 607 " [-u locuser]", "command" 608 #else 609 "", "[command]" 610 #endif 611 ); 612 exit(1); 613 } 614