1 /* $NetBSD: rsh.c,v 1.13 2000/01/31 14:19:34 itojun 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 1.13 2000/01/31 14:19:34 itojun 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 <stdio.h> 64 #include <stdlib.h> 65 #include <string.h> 66 #include <unistd.h> 67 #ifdef __STDC__ 68 #include <stdarg.h> 69 #else 70 #include <varargs.h> 71 #endif 72 73 #include "pathnames.h" 74 75 #ifdef KERBEROS 76 #include <kerberosIV/des.h> 77 #include <kerberosIV/krb.h> 78 79 CREDENTIALS cred; 80 Key_schedule schedule; 81 int use_kerberos = 1, doencrypt; 82 char dst_realm_buf[REALM_SZ], *dest_realm; 83 84 void warning __P((const char *, ...)); 85 #endif 86 87 /* 88 * rsh - remote shell 89 */ 90 extern char *__progname; /* XXX */ 91 int remerr; 92 93 static int sigs[] = { SIGINT, SIGTERM, SIGQUIT }; 94 95 char *copyargs __P((char **)); 96 void sendsig __P((int)); 97 int checkfd __P((struct pollfd *, int)); 98 void talk __P((int, sigset_t *, pid_t, int)); 99 void usage __P((void)); 100 int main __P((int, char **)); 101 #ifdef IN_RCMD 102 int orcmd __P((char **, int, const char *, 103 const char *, const char *, int *)); 104 int orcmd_af __P((char **, int, const char *, 105 const char *, const char *, int *, int)); 106 #endif 107 108 int 109 main(argc, argv) 110 int argc; 111 char **argv; 112 { 113 struct passwd *pw; 114 struct servent *sp; 115 sigset_t oset, nset; 116 117 #ifdef IN_RCMD 118 char *locuser = 0, *loop; 119 #endif /* IN_RCMD */ 120 int argoff, asrsh, ch, dflag, nflag, one, rem, i; 121 pid_t pid; 122 uid_t uid; 123 char *args, *host, *p, *user, *name; 124 125 argoff = asrsh = dflag = nflag = 0; 126 one = 1; 127 host = user = NULL; 128 129 #ifndef IN_RCMD 130 /* 131 * If called as something other than "rsh" use it as the host name, 132 * only for rsh. 133 */ 134 p = __progname; 135 if (strcmp(p, "rsh") == 0) 136 asrsh = 1; 137 else 138 host = p; 139 #endif /* IN_RCMD */ 140 141 /* handle "rsh host flags" */ 142 if (!host && argc > 2 && argv[1][0] != '-') { 143 host = argv[1]; 144 argoff = 1; 145 } 146 147 #ifdef IN_RCMD 148 if ((loop = getenv("RCMD_LOOP")) && strcmp(loop, "YES") == 0) 149 warnx("rcmd appears to be looping!"); 150 151 putenv("RCMD_LOOP=YES"); 152 153 # ifdef KERBEROS 154 # ifdef CRYPT 155 # define OPTIONS "8KLdek:l:nu:wx" 156 # else 157 # define OPTIONS "8KLdek:l:nu:w" 158 # endif 159 # else 160 # define OPTIONS "8KLdel:nu:w" 161 # endif 162 163 #else /* IN_RCMD */ 164 165 # ifdef KERBEROS 166 # ifdef CRYPT 167 # define OPTIONS "8KLdek:l:nwx" 168 # else 169 # define OPTIONS "8KLdek:l:nw" 170 # endif 171 # else 172 # define OPTIONS "8KLdel:nw" 173 # endif 174 175 #endif /* IN_RCMD */ 176 177 if (!(pw = getpwuid(uid = getuid()))) 178 errx(1, "unknown user id"); 179 180 if ((name = strdup(pw->pw_name)) == NULL) 181 err(1, "malloc"); 182 while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != -1) 183 switch(ch) { 184 case 'K': 185 #ifdef KERBEROS 186 use_kerberos = 0; 187 #endif 188 break; 189 case 'L': /* -8Lew are ignored to allow rlogin aliases */ 190 case 'e': 191 case 'w': 192 case '8': 193 break; 194 case 'd': 195 dflag = 1; 196 break; 197 case 'l': 198 user = optarg; 199 break; 200 #ifdef KERBEROS 201 case 'k': 202 dest_realm = dst_realm_buf; 203 strncpy(dest_realm, optarg, REALM_SZ); 204 break; 205 #endif 206 case 'n': 207 nflag = 1; 208 break; 209 #ifdef IN_RCMD 210 case 'u': 211 if (getuid() != 0 && optarg && name && 212 strcmp(name, optarg) != 0) 213 errx(1,"only super user can use the -u option"); 214 locuser = optarg; 215 break; 216 #endif /* IN_RCMD */ 217 #ifdef KERBEROS 218 #ifdef CRYPT 219 case 'x': 220 doencrypt = 1; 221 des_set_key((des_cblock *) cred.session, schedule); 222 break; 223 #endif 224 #endif 225 case '?': 226 default: 227 usage(); 228 } 229 optind += argoff; 230 231 /* if haven't gotten a host yet, do so */ 232 if (!host && !(host = argv[optind++])) 233 usage(); 234 235 /* if no further arguments, must have been called as rlogin. */ 236 if (!argv[optind]) { 237 #ifdef IN_RCMD 238 usage(); 239 #else 240 if (asrsh) 241 *argv = "rlogin"; 242 execv(_PATH_RLOGIN, argv); 243 err(1, "can't exec %s", _PATH_RLOGIN); 244 #endif 245 } 246 247 argc -= optind; 248 argv += optind; 249 250 /* Accept user1@host format, though "-l user2" overrides user1 */ 251 p = strchr(host, '@'); 252 if (p) { 253 *p = '\0'; 254 if (!user && p > host) 255 user = host; 256 host = p + 1; 257 if (*host == '\0') 258 usage(); 259 } 260 if (!user) 261 user = name; 262 263 #ifdef KERBEROS 264 #ifdef CRYPT 265 /* -x turns off -n */ 266 if (doencrypt) 267 nflag = 0; 268 #endif 269 #endif 270 271 args = copyargs(argv); 272 273 sp = NULL; 274 #ifdef KERBEROS 275 if (use_kerberos) { 276 sp = getservbyname((doencrypt ? "ekshell" : "kshell"), "tcp"); 277 if (sp == NULL) { 278 use_kerberos = 0; 279 warning("can't get entry for %s/tcp service", 280 doencrypt ? "ekshell" : "kshell"); 281 } 282 } 283 #endif 284 if (sp == NULL) 285 sp = getservbyname("shell", "tcp"); 286 if (sp == NULL) 287 errx(1, "shell/tcp: unknown service"); 288 289 #ifdef KERBEROS 290 try_connect: 291 if (use_kerberos) { 292 #if 1 293 struct hostent *hp; 294 295 /* fully qualify hostname (needed for krb_realmofhost) */ 296 hp = gethostbyname(host); 297 if (hp != NULL && !(host = strdup(hp->h_name))) 298 err(1, "strdup"); 299 #endif 300 301 rem = KSUCCESS; 302 errno = 0; 303 if (dest_realm == NULL) 304 dest_realm = krb_realmofhost(host); 305 306 #ifdef CRYPT 307 if (doencrypt) 308 rem = krcmd_mutual(&host, sp->s_port, user, args, 309 &remerr, dest_realm, &cred, schedule); 310 else 311 #endif 312 rem = krcmd(&host, sp->s_port, user, args, &remerr, 313 dest_realm); 314 if (rem < 0) { 315 use_kerberos = 0; 316 sp = getservbyname("shell", "tcp"); 317 if (sp == NULL) 318 errx(1, "shell/tcp: unknown service"); 319 if (errno == ECONNREFUSED) 320 warning("remote host doesn't support Kerberos"); 321 if (errno == ENOENT) 322 warning("can't provide Kerberos auth data"); 323 goto try_connect; 324 } 325 } else { 326 if (doencrypt) 327 errx(1, "the -x flag requires Kerberos authentication."); 328 #ifdef IN_RCMD 329 rem = orcmd_af(&host, sp->s_port, locuser ? locuser : 330 #else 331 rem = rcmd_af(&host, sp->s_port, 332 #endif 333 name, 334 user, args, &remerr, PF_UNSPEC); 335 } 336 #else /* KERBEROS */ 337 338 #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, user, args, &remerr, PF_UNSPEC); 344 #endif /* KERBEROS */ 345 (void)free(name); 346 347 if (rem < 0) 348 exit(1); 349 350 if (remerr < 0) 351 errx(1, "can't establish stderr"); 352 if (dflag) { 353 if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one, 354 sizeof(one)) < 0) 355 warn("setsockopt remote"); 356 if (setsockopt(remerr, SOL_SOCKET, SO_DEBUG, &one, 357 sizeof(one)) < 0) 358 warn("setsockopt stderr"); 359 } 360 361 (void) setuid(uid); 362 363 (void) sigemptyset(&nset); 364 for (i = 0; i < sizeof(sigs) / sizeof(sigs[0]); i++) 365 (void) sigaddset(&nset, sigs[i]); 366 367 (void) sigprocmask(SIG_BLOCK, &nset, &oset); 368 369 for (i = 0; i < sizeof(sigs) / sizeof(sigs[0]); i++) { 370 struct sigaction sa; 371 372 if (sa.sa_handler != SIG_IGN) { 373 sa.sa_handler = sendsig; 374 (void) sigaction(sigs[i], &sa, NULL); 375 } 376 } 377 378 if (!nflag) { 379 pid = fork(); 380 if (pid < 0) 381 err(1, "fork"); 382 } 383 else 384 pid = -1; 385 386 #if defined(KERBEROS) && defined(CRYPT) 387 if (!doencrypt) 388 #endif 389 { 390 (void)ioctl(remerr, FIONBIO, &one); 391 (void)ioctl(rem, FIONBIO, &one); 392 } 393 394 talk(nflag, &oset, pid, rem); 395 396 if (!nflag) 397 (void)kill(pid, SIGKILL); 398 exit(0); 399 } 400 401 int 402 checkfd(fdp, outfd) 403 struct pollfd *fdp; 404 int outfd; 405 { 406 int nr, nw; 407 char buf[BUFSIZ]; 408 409 if (fdp->revents & (POLLNVAL|POLLERR|POLLHUP)) 410 return -1; 411 412 if ((fdp->revents & POLLIN) == 0) 413 return 0; 414 415 errno = 0; 416 #if defined(KERBEROS) && defined(CRYPT) 417 if (doencrypt) 418 nr = des_read(fdp->fd, buf, sizeof buf); 419 else 420 #endif 421 nr = read(fdp->fd, buf, sizeof buf); 422 423 if (nr <= 0) { 424 if (errno != EAGAIN) 425 return -1; 426 else 427 return 0; 428 } 429 else { 430 char *bc = buf; 431 while (nr) { 432 if ((nw = write(outfd, bc, nr)) <= 0) 433 return -1; 434 nr -= nw; 435 bc += nw; 436 } 437 return 0; 438 } 439 } 440 441 void 442 talk(nflag, oset, pid, rem) 443 int nflag; 444 sigset_t *oset; 445 pid_t pid; 446 int rem; 447 { 448 int nr, nw, nfds; 449 struct pollfd fds[2], *fdp = &fds[0]; 450 char *bp, buf[BUFSIZ]; 451 452 453 if (!nflag && pid == 0) { 454 (void)close(remerr); 455 456 fdp->events = POLLOUT|POLLNVAL|POLLERR|POLLHUP; 457 fdp->fd = rem; 458 nr = 0; 459 bp = buf; 460 461 for (;;) { 462 errno = 0; 463 464 if (nr == 0) { 465 if ((nr = read(0, buf, sizeof buf)) == 0) 466 goto done; 467 if (nr == -1) { 468 if (errno == EIO) 469 goto done; 470 if (errno == EINTR) 471 continue; 472 err(1, "read"); 473 } 474 bp = buf; 475 } 476 477 rewrite: if (poll(fdp, 1, INFTIM) == -1) { 478 if (errno != EINTR) 479 err(1, "poll"); 480 goto rewrite; 481 } 482 483 if (fdp->revents & (POLLNVAL|POLLERR|POLLHUP)) 484 err(1, "poll"); 485 486 if ((fdp->revents & POLLOUT) == 0) 487 goto rewrite; 488 489 #if defined(KERBEROS) && defined(CRYPT) 490 if (doencrypt) 491 nw = des_write(rem, bp, nr); 492 else 493 #endif 494 nw = write(rem, bp, nr); 495 496 if (nw < 0) { 497 if (errno == EAGAIN) 498 continue; 499 err(1, "write"); 500 } 501 bp += nw; 502 nr -= nw; 503 } 504 done: 505 (void)shutdown(rem, 1); 506 exit(0); 507 } 508 509 (void) sigprocmask(SIG_SETMASK, oset, NULL); 510 fds[0].events = fds[1].events = POLLIN|POLLNVAL|POLLERR|POLLHUP; 511 fds[0].fd = remerr; 512 fds[1].fd = rem; 513 fdp = &fds[0]; 514 nfds = 2; 515 do { 516 if (poll(fdp, nfds, INFTIM) == -1) { 517 if (errno != EINTR) 518 err(1, "poll"); 519 continue; 520 } 521 if (fds[0].events != 0 && checkfd(&fds[0], 2) == -1) { 522 nfds--; 523 fds[0].events = 0; 524 fdp = &fds[1]; 525 } 526 if (fds[1].events != 0 && checkfd(&fds[1], 1) == -1) { 527 nfds--; 528 fds[1].events = 0; 529 } 530 } 531 while (nfds); 532 } 533 534 void 535 sendsig(sig) 536 int sig; 537 { 538 char signo; 539 540 signo = sig; 541 #ifdef KERBEROS 542 #ifdef CRYPT 543 if (doencrypt) 544 (void)des_write(remerr, &signo, 1); 545 else 546 #endif 547 #endif 548 (void)write(remerr, &signo, 1); 549 } 550 551 #ifdef KERBEROS 552 /* VARARGS */ 553 void 554 #ifdef __STDC__ 555 warning(const char *fmt, ...) 556 #else 557 warning(va_alist) 558 va_dcl 559 #endif 560 { 561 va_list ap; 562 #ifndef __STDC__ 563 const char *fmt; 564 565 va_start(ap); 566 fmt = va_arg(ap, const char *); 567 #else 568 va_start(ap, fmt); 569 #endif 570 571 (void) fprintf(stderr, "%s: warning, using standard rsh: ", __progname); 572 (void) vfprintf(stderr, fmt, ap); 573 va_end(ap); 574 (void) fprintf(stderr, ".\n"); 575 } 576 #endif 577 578 char * 579 copyargs(argv) 580 char **argv; 581 { 582 int cc; 583 char **ap, *args, *p; 584 585 cc = 0; 586 for (ap = argv; *ap; ++ap) 587 cc += strlen(*ap) + 1; 588 if (!(args = malloc((u_int)cc))) 589 err(1, "malloc"); 590 for (p = args, *p = '\0', ap = argv; *ap; ++ap) { 591 (void)strcpy(p, *ap); 592 p += strlen(p); 593 if (ap[1]) 594 *p++ = ' '; 595 } 596 *p = '\0'; 597 return (args); 598 } 599 600 void 601 usage() 602 { 603 604 (void)fprintf(stderr, 605 "usage: %s [-nd%s]%s[-l login]%s [login@]host %s\n", __progname, 606 #ifdef KERBEROS 607 #ifdef CRYPT 608 "x", " [-k realm] ", 609 #else 610 "", " [-k realm] ", 611 #endif 612 #else 613 "", " ", 614 #endif 615 #ifdef IN_RCMD 616 " [-u locuser]", "command" 617 #else 618 "", "[command]" 619 #endif 620 ); 621 exit(1); 622 } 623