commands/rsh/rsh.c

   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 #if 0
  42 static char sccsid[] = "@(#)rsh.c       5.24 (Berkeley) 7/1/91";
  43 #endif
  44 #endif /* not lint */
  45
  46 /*
  47  * $Source$
  48  * $Header$
  49  */
  50
  51 #if _MINIX
  52 #include <sys/types.h>
  53 #include <sys/ioctl.h>
  54 #include <errno.h>
  55 #include <pwd.h>
  56 #include <signal.h>
  57 #include <stdio.h>
  58 #include <stdlib.h>
  59 #include <string.h>
  60 #include <unistd.h>
  61
  62 #include <net/netlib.h>
  63 #include <net/gen/netdb.h>
  64 int main( int argc, char *argv[] );
  65 void usage( void );
  66 char *copyargs( char **argv );
  67 void sendsig( int signo );
  68 void talk( int nflag, long omask, int pid, int rem );
  69
  70 #define _PATH_RLOGIN1   "/bin/rlogin"
  71 #define _PATH_RLOGIN2   "/usr/bin/rlogin"
  72
  73 #else
  74 #include <sys/types.h>
  75 #include <sys/signal.h>
  76 #include <sys/socket.h>
  77 #include <sys/ioctl.h>
  78 #include <sys/file.h>
  79
  80 #include <netinet/in.h>
  81 #include <netdb.h>
  82
  83 #include <pwd.h>
  84 #include <stdio.h>
  85 #include <errno.h>
  86 #include <string.h>
  87 #include <varargs.h>
  88 #include "pathnames.h"
  89 #endif
  90
  91 #ifdef KERBEROS
  92 #include <kerberosIV/des.h>
  93 #include <kerberosIV/krb.h>
  94
  95 CREDENTIALS cred;
  96 Key_schedule schedule;
  97 int use_kerberos = 1, doencrypt;
  98 char dst_realm_buf[REALM_SZ], *dest_realm;
  99 extern char *krb_realmofhost();
 100 #endif
 101
 102 /*
 103  * rsh - remote shell
 104  */
 105 extern int errno;
 106 int rfd2;
 107
 108 int
 109 main(argc, argv)
 110         int argc;
 111         char **argv;
 112 {
 113         extern char *optarg;
 114         extern int optind;
 115         struct passwd *pw;
 116         struct servent *sp;
 117         long omask;
 118         int argoff, asrsh, ch, dflag, nflag, one, pid, rem, uid;
 119         register char *p;
 120         char *args, *host, *user;
 121 #if !_MINIX
 122         char *copyargs();
 123         void sendsig();
 124 #endif
 125
 126         argoff = asrsh = dflag = nflag = 0;
 127         one = 1;
 128         host = user = NULL;
 129
 130         /* if called as something other than "rsh", use it as the host name */
 131         if ((p = rindex(argv[0], '/')))
 132                 ++p;
 133         else
 134                 p = argv[0];
 135         if (strcmp(p, "rsh"))
 136                 host = p;
 137         else
 138                 asrsh = 1;
 139
 140         /* handle "rsh host flags" */
 141         if (!host && argc > 2 && argv[1][0] != '-') {
 142                 host = argv[1];
 143                 argoff = 1;
 144         }
 145
 146 #ifdef KERBEROS
 147 #ifdef CRYPT
 148 #define OPTIONS "8KLdek:l:nwx"
 149 #else
 150 #define OPTIONS "8KLdek:l:nw"
 151 #endif
 152 #else
 153 #define OPTIONS "8KLdel:nw"
 154 #endif
 155         while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != EOF)
 156                 switch(ch) {
 157                 case 'K':
 158 #ifdef KERBEROS
 159                         use_kerberos = 0;
 160 #endif
 161                         break;
 162                 case 'L':       /* -8Lew are ignored to allow rlogin aliases */
 163                 case 'e':
 164                 case 'w':
 165                 case '8':
 166                         break;
 167                 case 'd':
 168                         dflag = 1;
 169                         break;
 170                 case 'l':
 171                         user = optarg;
 172                         break;
 173 #ifdef KERBEROS
 174                 case 'k':
 175                         dest_realm = dst_realm_buf;
 176                         strncpy(dest_realm, optarg, REALM_SZ);
 177                         break;
 178 #endif
 179                 case 'n':
 180                         nflag = 1;
 181                         break;
 182 #ifdef KERBEROS
 183 #ifdef CRYPT
 184                 case 'x':
 185                         doencrypt = 1;
 186                         des_set_key(cred.session, schedule);
 187                         break;
 188 #endif
 189 #endif
 190                 case '?':
 191                 default:
 192                         usage();
 193                 }
 194         optind += argoff;
 195
 196         /* if haven't gotten a host yet, do so */
 197         if (!host && !(host = argv[optind++]))
 198                 usage();
 199
 200         /* if no further arguments, must have been called as rlogin. */
 201         if (!argv[optind]) {
 202                 if (asrsh)
 203                         *argv = "rlogin";
 204                 execv(_PATH_RLOGIN1, argv);
 205                 execv(_PATH_RLOGIN2, argv);
 206                 (void)fprintf(stderr, "rsh: can't exec rlogin\n");
 207                 exit(1);
 208         }
 209
 210         argc -= optind;
 211         argv += optind;
 212
 213         if (!(pw = getpwuid(uid = getuid()))) {
 214                 (void)fprintf(stderr, "rsh: unknown user id.\n");
 215                 exit(1);
 216         }
 217         if (!user)
 218                 user = pw->pw_name;
 219
 220 #ifdef KERBEROS
 221 #ifdef CRYPT
 222         /* -x turns off -n */
 223         if (doencrypt)
 224                 nflag = 0;
 225 #endif
 226 #endif
 227
 228         args = copyargs(argv);
 229
 230         sp = NULL;
 231 #ifdef KERBEROS
 232         if (use_kerberos) {
 233                 sp = getservbyname((doencrypt ? "ekshell" : "kshell"), "tcp");
 234                 if (sp == NULL) {
 235                         use_kerberos = 0;
 236                         warning("can't get entry for %s/tcp service",
 237                             doencrypt ? "ekshell" : "kshell");
 238                 }
 239         }
 240 #endif
 241         if (sp == NULL)
 242                 sp = getservbyname("shell", "tcp");
 243         if (sp == NULL) {
 244                 (void)fprintf(stderr, "rsh: shell/tcp: unknown service.\n");
 245                 exit(1);
 246         }
 247
 248 #ifdef KERBEROS
 249 try_connect:
 250         if (use_kerberos) {
 251                 rem = KSUCCESS;
 252                 errno = 0;
 253                 if (dest_realm == NULL)
 254                         dest_realm = krb_realmofhost(host);
 255
 256 #ifdef CRYPT
 257                 if (doencrypt)
 258                         rem = krcmd_mutual(&host, sp->s_port, user, args,
 259                             &rfd2, dest_realm, &cred, schedule);
 260                 else
 261 #endif
 262                         rem = krcmd(&host, sp->s_port, user, args, &rfd2,
 263                             dest_realm);
 264                 if (rem < 0) {
 265                         use_kerberos = 0;
 266                         sp = getservbyname("shell", "tcp");
 267                         if (sp == NULL) {
 268                                 (void)fprintf(stderr,
 269                                     "rsh: unknown service shell/tcp.\n");
 270                                 exit(1);
 271                         }
 272                         if (errno == ECONNREFUSED)
 273                                 warning("remote host doesn't support Kerberos");
 274                         if (errno == ENOENT)
 275                                 warning("can't provide Kerberos auth data");
 276                         goto try_connect;
 277                 }
 278         } else {
 279                 if (doencrypt) {
 280                         (void)fprintf(stderr,
 281                             "rsh: the -x flag requires Kerberos authentication.\n");
 282                         exit(1);
 283                 }
 284                 rem = rcmd(&host, sp->s_port, pw->pw_name, user, args, &rfd2);
 285         }
 286 #else
 287         rem = rcmd(&host, sp->s_port, pw->pw_name, user, args, &rfd2);
 288 #endif
 289
 290         if (rem < 0)
 291                 exit(1);
 292
 293         if (rfd2 < 0) {
 294                 (void)fprintf(stderr, "rsh: can't establish stderr.\n");
 295                 exit(1);
 296         }
 297 #if !_MINIX
 298         if (dflag) {
 299                 if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one,
 300                     sizeof(one)) < 0)
 301                         (void)fprintf(stderr, "rsh: setsockopt: %s.\n",
 302                             strerror(errno));
 303                 if (setsockopt(rfd2, SOL_SOCKET, SO_DEBUG, &one,
 304                     sizeof(one)) < 0)
 305                         (void)fprintf(stderr, "rsh: setsockopt: %s.\n",
 306                             strerror(errno));
 307         }
 308 #endif
 309
 310         (void)setuid(uid);
 311 #if !_MINIX
 312         omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGTERM));
 313 #endif
 314         if (signal(SIGINT, SIG_IGN) != SIG_IGN)
 315                 (void)signal(SIGINT, sendsig);
 316         if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
 317                 (void)signal(SIGQUIT, sendsig);
 318         if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
 319                 (void)signal(SIGTERM, sendsig);
 320
 321         if (!nflag) {
 322                 pid = fork();
 323                 if (pid < 0) {
 324                         (void)fprintf(stderr,
 325                             "rsh: fork: %s.\n", strerror(errno));
 326                         exit(1);
 327                 }
 328         }
 329
 330 #ifdef KERBEROS
 331 #ifdef CRYPT
 332         if (!doencrypt)
 333 #endif
 334 #endif
 335         {
 336 #if _MINIX
 337                 ;
 338 #else
 339                 (void)ioctl(rfd2, FIONBIO, &one);
 340                 (void)ioctl(rem, FIONBIO, &one);
 341 #endif
 342         }
 343
 344         talk(nflag, omask, pid, rem);
 345
 346         if (!nflag && pid)
 347         {
 348 #if DEBUG
 349                 printf("killing %d with %d\n", pid, SIGKILL);
 350 #endif
 351                 (void)kill(pid, SIGKILL);
 352         }
 353         exit(0);
 354 }
 355
 356 void
 357 talk(nflag, omask, pid, rem)
 358         int nflag, pid;
 359         long omask;
 360         register int rem;
 361 {
 362         register int cc, wc;
 363         register char *bp;
 364 #if !_MINIX
 365         int readfrom, ready, rembits;
 366 #endif
 367         char buf[BUFSIZ];
 368 #if _MINIX
 369         int pid1;
 370 #endif
 371
 372         if (!nflag && pid == 0) {
 373                 (void)close(rfd2);
 374
 375 reread:         errno = 0;
 376                 if ((cc = read(0, buf, sizeof buf)) <= 0)
 377                         goto done;
 378                 bp = buf;
 379
 380 rewrite:
 381 #if !_MINIX
 382                 rembits = 1 << rem;
 383                 if (select(16, 0, &rembits, 0, 0) < 0) {
 384                         if (errno != EINTR) {
 385                                 (void)fprintf(stderr,
 386                                     "rsh: select: %s.\n", strerror(errno));
 387                                 exit(1);
 388                         }
 389                         goto rewrite;
 390                 }
 391                 if ((rembits & (1 << rem)) == 0)
 392                         goto rewrite;
 393 #endif
 394 #ifdef KERBEROS
 395 #ifdef CRYPT
 396                 if (doencrypt)
 397                         wc = des_write(rem, bp, cc);
 398                 else
 399 #endif
 400 #endif
 401                         wc = write(rem, bp, cc);
 402                 if (wc < 0) {
 403 #if !_MINIX
 404                         if (errno == EWOULDBLOCK)
 405                                 goto rewrite;
 406 #endif
 407                         goto done;
 408                 }
 409                 bp += wc;
 410                 cc -= wc;
 411                 if (cc == 0)
 412                         goto reread;
 413                 goto rewrite;
 414 done:
 415 #if _MINIX
 416                 ioctl(rem, NWIOTCPSHUTDOWN, NULL);
 417 #else
 418                 (void)shutdown(rem, 1);
 419 #endif
 420                 exit(0);
 421         }
 422
 423 #if _MINIX
 424         pid1= fork();
 425         if (pid1 == -1)
 426         {
 427                 (void)fprintf(stderr, "rsh: fork: %s.\n", strerror(errno));
 428                 exit(1);
 429         }
 430         close (pid1 ? rfd2 : rem);
 431         for(;;)
 432         {
 433                 errno = 0;
 434                 cc = read(pid1 ? rem : rfd2, buf, sizeof buf);
 435                 if (cc <= 0)
 436                 {
 437                         if (pid1)
 438                         {
 439 #if DEBUG
 440                                 printf("killing %d with %d\n", pid1, SIGKILL);
 441 #endif
 442                                 kill(pid1, SIGKILL);
 443                                 return;
 444                         }
 445                         exit(0);
 446                 }
 447                 (void)write(pid1 ? 1 : 2, buf, cc);
 448         }
 449 #else
 450         (void)sigsetmask(omask);
 451         readfrom = (1 << rfd2) | (1 << rem);
 452         do {
 453                 ready = readfrom;
 454                 if (select(16, &ready, 0, 0, 0) < 0) {
 455                         if (errno != EINTR) {
 456                                 (void)fprintf(stderr,
 457                                     "rsh: select: %s.\n", strerror(errno));
 458                                 exit(1);
 459                         }
 460                         continue;
 461                 }
 462                 if (ready & (1 << rfd2)) {
 463                         errno = 0;
 464 #ifdef KERBEROS
 465 #ifdef CRYPT
 466                         if (doencrypt)
 467                                 cc = des_read(rfd2, buf, sizeof buf);
 468                         else
 469 #endif
 470 #endif
 471                                 cc = read(rfd2, buf, sizeof buf);
 472                         if (cc <= 0) {
 473                                 if (errno != EWOULDBLOCK)
 474                                         readfrom &= ~(1 << rfd2);
 475                         } else
 476                                 (void)write(2, buf, cc);
 477                 }
 478                 if (ready & (1 << rem)) {
 479                         errno = 0;
 480 #ifdef KERBEROS
 481 #ifdef CRYPT
 482                         if (doencrypt)
 483                                 cc = des_read(rem, buf, sizeof buf);
 484                         else
 485 #endif
 486 #endif
 487                                 cc = read(rem, buf, sizeof buf);
 488                         if (cc <= 0) {
 489                                 if (errno != EWOULDBLOCK)
 490                                         readfrom &= ~(1 << rem);
 491                         } else
 492                                 (void)write(1, buf, cc);
 493                 }
 494         } while (readfrom);
 495 #endif
 496 }
 497
 498 void
 499 sendsig(signo)
 500         char signo;
 501 {
 502 #ifdef KERBEROS
 503 #ifdef CRYPT
 504         if (doencrypt)
 505                 (void)des_write(rfd2, &signo, 1);
 506         else
 507 #endif
 508 #endif
 509                 (void)write(rfd2, &signo, 1);
 510 }
 511
 512 #ifdef KERBEROS
 513 /* VARARGS */
 514 warning(va_alist)
 515 va_dcl
 516 {
 517         va_list ap;
 518         char *fmt;
 519
 520         (void)fprintf(stderr, "rsh: warning, using standard rsh: ");
 521         va_start(ap);
 522         fmt = va_arg(ap, char *);
 523         vfprintf(stderr, fmt, ap);
 524         va_end(ap);
 525         (void)fprintf(stderr, ".\n");
 526 }
 527 #endif
 528
 529 char *
 530 copyargs(argv)
 531         char **argv;
 532 {
 533         register int cc;
 534         register char **ap, *p;
 535         char *args;
 536 #if !_MINIX
 537         char *malloc();
 538 #endif
 539
 540         cc = 0;
 541         for (ap = argv; *ap; ++ap)
 542                 cc += strlen(*ap) + 1;
 543         if (!(args = malloc((u_int)cc))) {
 544                 (void)fprintf(stderr, "rsh: %s.\n", strerror(ENOMEM));
 545                 exit(1);
 546         }
 547         for (p = args, ap = argv; *ap; ++ap) {
 548                 (void)strcpy(p, *ap);
 549                 for (p = strcpy(p, *ap); *p; ++p);
 550                 if (ap[1])
 551                         *p++ = ' ';
 552         }
 553         return(args);
 554 }
 555
 556 void
 557 usage()
 558 {
 559         (void)fprintf(stderr,
 560             "usage: rsh [-nd%s]%s[-l login] host [command]\n",
 561 #ifdef KERBEROS
 562 #ifdef CRYPT
 563             "x", " [-k realm] ");
 564 #else
 565             "", " [-k realm] ");
 566 #endif
 567 #else
 568             "", " ");
 569 #endif
 570         exit(1);
 571 }