1 /* 2 * Copyright (c) 1983, 1988, 1989 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 */ 17 18 #ifndef lint 19 char copyright[] = 20 "@(#) Copyright (c) 1983, 1988, 1989 The Regents of the University of California.\n\ 21 All rights reserved.\n"; 22 #endif /* not lint */ 23 24 #ifndef lint 25 static char sccsid[] = "@(#)rlogind.c 5.38 (Berkeley) 09/11/89"; 26 #endif /* not lint */ 27 28 #ifdef KERBEROS 29 /* From: 30 * $Source: /mit/kerberos/ucb/mit/rlogind/RCS/rlogind.c,v $ 31 * $Header: rlogind.c,v 5.0 89/06/26 18:31:01 kfall Locked $ 32 */ 33 34 #endif 35 /* 36 * remote login server: 37 * \0 38 * remuser\0 39 * locuser\0 40 * terminal_type/speed\0 41 * data 42 */ 43 44 #include <sys/param.h> 45 #include <sys/stat.h> 46 #include <sys/socket.h> 47 #include <sys/wait.h> 48 #include <sys/file.h> 49 #include <sys/signal.h> 50 #include <sys/ioctl.h> 51 #include <sys/termios.h> 52 53 #include <netinet/in.h> 54 55 #include <errno.h> 56 #include <pwd.h> 57 #include <netdb.h> 58 #include <syslog.h> 59 #include <strings.h> 60 #include <stdio.h> 61 #include "pathnames.h" 62 63 #ifndef TIOCPKT_WINDOW 64 #define TIOCPKT_WINDOW 0x80 65 #endif 66 67 #ifdef KERBEROS 68 #include <krb.h> 69 #define SECURE_MESSAGE "This rlogin session is using DES encryption for all transmissions.\r\n" 70 71 AUTH_DAT *kdata; 72 KTEXT ticket; 73 u_char auth_buf[sizeof(AUTH_DAT)]; 74 u_char tick_buf[sizeof(KTEXT_ST)]; 75 Key_schedule schedule; 76 int encrypt = 0, retval, use_kerberos = 0, vacuous = 0; 77 int do_krb_login(); 78 79 #define ARGSTR "alnkvx" 80 #else 81 #define ARGSTR "aln" 82 #endif /* KERBEROS */ 83 84 char *env[2]; 85 #define NMAX 30 86 char lusername[NMAX+1], rusername[NMAX+1]; 87 static char term[64] = "TERM="; 88 #define ENVSIZE (sizeof("TERM=")-1) /* skip null for concatenation */ 89 int keepalive = 1; 90 int check_all = 0; 91 92 #define SUPERUSER(pwd) ((pwd)->pw_uid == 0) 93 94 extern int errno; 95 int reapchild(); 96 struct passwd *getpwnam(), *pwd; 97 char *malloc(); 98 99 main(argc, argv) 100 int argc; 101 char **argv; 102 { 103 extern int opterr, optind; 104 extern int _check_rhosts_file; 105 int ch; 106 int on = 1, fromlen; 107 struct sockaddr_in from; 108 109 openlog("rlogind", LOG_PID | LOG_CONS, LOG_AUTH); 110 111 opterr = 0; 112 while ((ch = getopt(argc, argv, ARGSTR)) != EOF) 113 switch (ch) { 114 case 'a': 115 check_all = 1; 116 break; 117 case 'l': 118 _check_rhosts_file = 0; 119 break; 120 case 'n': 121 keepalive = 0; 122 break; 123 #ifdef KERBEROS 124 case 'k': 125 use_kerberos = 1; 126 break; 127 case 'v': 128 vacuous = 1; 129 break; 130 case 'x': 131 encrypt = 1; 132 break; 133 #endif 134 case '?': 135 default: 136 usage(); 137 break; 138 } 139 argc -= optind; 140 argv += optind; 141 142 #ifdef KERBEROS 143 if (use_kerberos && vacuous) { 144 usage(); 145 fatal("only one of -k and -v allowed"); 146 } 147 #endif 148 fromlen = sizeof (from); 149 if (getpeername(0, &from, &fromlen) < 0) { 150 syslog(LOG_ERR,"Can't get peer name of remote host: %m"); 151 fatalperror("Can't get peer name of remote host"); 152 } 153 if (keepalive && 154 setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof (on)) < 0) 155 syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m"); 156 doit(0, &from); 157 } 158 159 int child; 160 int cleanup(); 161 int netf; 162 char *line; 163 extern char *inet_ntoa(); 164 165 struct winsize win = { 0, 0, 0, 0 }; 166 167 168 doit(f, fromp) 169 int f; 170 struct sockaddr_in *fromp; 171 { 172 int i, p, t, pid, on = 1; 173 int authenticated = 0, hostok = 0; 174 register struct hostent *hp; 175 char remotehost[2 * MAXHOSTNAMELEN + 1]; 176 struct hostent hostent; 177 char c; 178 179 alarm(60); 180 read(f, &c, 1); 181 182 if(c != 0) 183 exit(1); 184 #ifdef KERBEROS 185 if (vacuous) 186 fatal(f, "Remote host requires Kerberos authentication"); 187 #endif 188 189 alarm(0); 190 fromp->sin_port = ntohs((u_short)fromp->sin_port); 191 hp = gethostbyaddr(&fromp->sin_addr, sizeof (struct in_addr), 192 fromp->sin_family); 193 if (hp == 0) { 194 /* 195 * Only the name is used below. 196 */ 197 hp = &hostent; 198 hp->h_name = inet_ntoa(fromp->sin_addr); 199 hostok++; 200 } else if (check_all || local_domain(hp->h_name)) { 201 /* 202 * If name returned by gethostbyaddr is in our domain, 203 * attempt to verify that we haven't been fooled by someone 204 * in a remote net; look up the name and check that this 205 * address corresponds to the name. 206 */ 207 strncpy(remotehost, hp->h_name, sizeof(remotehost) - 1); 208 remotehost[sizeof(remotehost) - 1] = 0; 209 hp = gethostbyname(remotehost); 210 if (hp) 211 for (; hp->h_addr_list[0]; hp->h_addr_list++) 212 if (!bcmp(hp->h_addr_list[0], (caddr_t)&fromp->sin_addr, 213 sizeof(fromp->sin_addr))) { 214 hostok++; 215 break; 216 } 217 } else 218 hostok++; 219 220 #ifdef KERBEROS 221 if (use_kerberos) { 222 retval = do_krb_login(hp->h_name, fromp, encrypt); 223 write(f, &c, 1); 224 if (retval == 0 && hostok) 225 authenticated++; 226 else if (retval > 0) 227 fatal(f, krb_err_txt[retval]); 228 else if(!hostok) 229 fatal(f, "krlogind: Host address mismatch."); 230 } else 231 #endif 232 { 233 if (fromp->sin_family != AF_INET || 234 fromp->sin_port >= IPPORT_RESERVED || 235 fromp->sin_port < IPPORT_RESERVED/2) { 236 syslog(LOG_NOTICE, "Connection from %s on illegal port", 237 inet_ntoa(fromp->sin_addr)); 238 fatal(f, "Permission denied"); 239 } 240 #ifdef IP_OPTIONS 241 { 242 u_char optbuf[BUFSIZ/3], *cp; 243 char lbuf[BUFSIZ], *lp; 244 int optsize = sizeof(optbuf), ipproto; 245 struct protoent *ip; 246 247 if ((ip = getprotobyname("ip")) != NULL) 248 ipproto = ip->p_proto; 249 else 250 ipproto = IPPROTO_IP; 251 if (getsockopt(0, ipproto, IP_OPTIONS, (char *)optbuf, 252 &optsize) == 0 && optsize != 0) { 253 lp = lbuf; 254 for (cp = optbuf; optsize > 0; cp++, optsize--, lp += 3) 255 sprintf(lp, " %2.2x", *cp); 256 syslog(LOG_NOTICE, 257 "Connection received using IP options (ignored):%s", 258 lbuf); 259 if (setsockopt(0, ipproto, IP_OPTIONS, 260 (char *)NULL, &optsize) != 0) { 261 syslog(LOG_ERR, "setsockopt IP_OPTIONS NULL: %m"); 262 exit(1); 263 } 264 } 265 } 266 #endif 267 write(f, "", 1); 268 269 if (do_rlogin(hp->h_name) == 0) { 270 if (hostok) 271 authenticated++; 272 else 273 write(f, "rlogind: Host address mismatch.\r\n", 274 sizeof("rlogind: Host address mismatch.\r\n") - 1); 275 } 276 } 277 278 for (c = 'p'; c <= 's'; c++) { 279 struct stat stb; 280 line = "/dev/ptyXX"; 281 line[strlen("/dev/pty")] = c; 282 line[strlen("/dev/ptyp")] = '0'; 283 if (stat(line, &stb) < 0) 284 break; 285 for (i = 0; i < 16; i++) { 286 line[sizeof("/dev/ptyp") - 1] = "0123456789abcdef"[i]; 287 p = open(line, O_RDWR); 288 if (p > 0) 289 goto gotpty; 290 } 291 } 292 fatal(f, "Out of ptys"); 293 /*NOTREACHED*/ 294 gotpty: 295 (void) ioctl(p, TIOCSWINSZ, &win); 296 netf = f; 297 line[strlen("/dev/")] = 't'; 298 t = open(line, O_RDWR); 299 if (t < 0) 300 fatalperror(f, line); 301 if (fchmod(t, 0)) 302 fatalperror(f, line); 303 (void)signal(SIGHUP, SIG_IGN); 304 vhangup(); 305 (void)signal(SIGHUP, SIG_DFL); 306 t = open(line, O_RDWR); 307 if (t < 0) 308 fatalperror(f, line); 309 setup_term(t); 310 311 pid = fork(); 312 if (pid < 0) 313 fatalperror(f, ""); 314 if (pid == 0) { 315 if (setsid() < 0) 316 fatalperror(f, "setsid"); 317 if (ioctl(t, TIOCSCTTY, 0) < 0) 318 fatalperror(f, "ioctl(sctty)"); 319 close(f), close(p); 320 dup2(t, 0), dup2(t, 1), dup2(t, 2); 321 close(t); 322 323 if (authenticated) 324 execl(_PATH_LOGIN, "login", "-p", 325 "-h", hp->h_name, "-f", lusername, 0); 326 else 327 execl(_PATH_LOGIN, "login", "-p", 328 "-h", hp->h_name, lusername, 0); 329 fatalperror(2, _PATH_LOGIN); 330 /*NOTREACHED*/ 331 } 332 close(t); 333 334 #ifdef KERBEROS 335 /* 336 * If encrypted, don't turn on NBIO or the des read/write 337 * routines will croak. 338 */ 339 340 if (encrypt) 341 (void) des_write(f, SECURE_MESSAGE, sizeof(SECURE_MESSAGE)); 342 else 343 #endif 344 ioctl(f, FIONBIO, &on); 345 ioctl(p, FIONBIO, &on); 346 ioctl(p, TIOCPKT, &on); 347 signal(SIGTSTP, SIG_IGN); 348 signal(SIGCHLD, cleanup); 349 setpgrp(0, 0); 350 protocol(f, p); 351 signal(SIGCHLD, SIG_IGN); 352 cleanup(); 353 } 354 355 char magic[2] = { 0377, 0377 }; 356 char oobdata[] = {TIOCPKT_WINDOW}; 357 358 /* 359 * Handle a "control" request (signaled by magic being present) 360 * in the data stream. For now, we are only willing to handle 361 * window size changes. 362 */ 363 control(pty, cp, n) 364 int pty; 365 char *cp; 366 int n; 367 { 368 struct winsize w; 369 370 if (n < 4+sizeof (w) || cp[2] != 's' || cp[3] != 's') 371 return (0); 372 oobdata[0] &= ~TIOCPKT_WINDOW; /* we know he heard */ 373 bcopy(cp+4, (char *)&w, sizeof(w)); 374 w.ws_row = ntohs(w.ws_row); 375 w.ws_col = ntohs(w.ws_col); 376 w.ws_xpixel = ntohs(w.ws_xpixel); 377 w.ws_ypixel = ntohs(w.ws_ypixel); 378 (void)ioctl(pty, TIOCSWINSZ, &w); 379 return (4+sizeof (w)); 380 } 381 382 /* 383 * rlogin "protocol" machine. 384 */ 385 protocol(f, p) 386 int f, p; 387 { 388 char pibuf[1024], fibuf[1024], *pbp, *fbp; 389 register pcc = 0, fcc = 0; 390 int cc, nfd, pmask, fmask; 391 char cntl; 392 393 /* 394 * Must ignore SIGTTOU, otherwise we'll stop 395 * when we try and set slave pty's window shape 396 * (our controlling tty is the master pty). 397 */ 398 (void) signal(SIGTTOU, SIG_IGN); 399 send(f, oobdata, 1, MSG_OOB); /* indicate new rlogin */ 400 if (f > p) 401 nfd = f + 1; 402 else 403 nfd = p + 1; 404 fmask = 1 << f; 405 pmask = 1 << p; 406 for (;;) { 407 int ibits, obits, ebits; 408 409 ibits = 0; 410 obits = 0; 411 if (fcc) 412 obits |= pmask; 413 else 414 ibits |= fmask; 415 if (pcc >= 0) 416 if (pcc) 417 obits |= fmask; 418 else 419 ibits |= pmask; 420 ebits = pmask; 421 if (select(nfd, &ibits, obits ? &obits : (int *)NULL, 422 &ebits, 0) < 0) { 423 if (errno == EINTR) 424 continue; 425 fatalperror(f, "select"); 426 } 427 if (ibits == 0 && obits == 0 && ebits == 0) { 428 /* shouldn't happen... */ 429 sleep(5); 430 continue; 431 } 432 #define pkcontrol(c) ((c)&(TIOCPKT_FLUSHWRITE|TIOCPKT_NOSTOP|TIOCPKT_DOSTOP)) 433 if (ebits & pmask) { 434 cc = read(p, &cntl, 1); 435 if (cc == 1 && pkcontrol(cntl)) { 436 cntl |= oobdata[0]; 437 send(f, &cntl, 1, MSG_OOB); 438 if (cntl & TIOCPKT_FLUSHWRITE) { 439 pcc = 0; 440 ibits &= ~pmask; 441 } 442 } 443 } 444 if (ibits & fmask) { 445 #ifdef KERBEROS 446 if (encrypt) 447 fcc = des_read(f, fibuf, sizeof(fibuf)); 448 else 449 #endif 450 fcc = read(f, fibuf, sizeof(fibuf)); 451 if (fcc < 0 && errno == EWOULDBLOCK) 452 fcc = 0; 453 else { 454 register char *cp; 455 int left, n; 456 457 if (fcc <= 0) 458 break; 459 fbp = fibuf; 460 461 top: 462 for (cp = fibuf; cp < fibuf+fcc-1; cp++) 463 if (cp[0] == magic[0] && 464 cp[1] == magic[1]) { 465 left = fcc - (cp-fibuf); 466 n = control(p, cp, left); 467 if (n) { 468 left -= n; 469 if (left > 0) 470 bcopy(cp+n, cp, left); 471 fcc -= n; 472 goto top; /* n^2 */ 473 } 474 } 475 obits |= pmask; /* try write */ 476 } 477 } 478 479 if ((obits & pmask) && fcc > 0) { 480 cc = write(p, fbp, fcc); 481 if (cc > 0) { 482 fcc -= cc; 483 fbp += cc; 484 } 485 } 486 487 if (ibits & pmask) { 488 pcc = read(p, pibuf, sizeof (pibuf)); 489 pbp = pibuf; 490 if (pcc < 0 && errno == EWOULDBLOCK) 491 pcc = 0; 492 else if (pcc <= 0) 493 break; 494 else if (pibuf[0] == 0) { 495 pbp++, pcc--; 496 #ifdef KERBEROS 497 if (!encrypt) 498 #endif 499 obits |= fmask; /* try a write */ 500 } else { 501 if (pkcontrol(pibuf[0])) { 502 pibuf[0] |= oobdata[0]; 503 send(f, &pibuf[0], 1, MSG_OOB); 504 } 505 pcc = 0; 506 } 507 } 508 if ((obits & fmask) && pcc > 0) { 509 #ifdef KERBEROS 510 if (encrypt) 511 cc = des_write(f, pbp, pcc); 512 else 513 #endif 514 cc = write(f, pbp, pcc); 515 if (cc < 0 && errno == EWOULDBLOCK) { 516 /* also shouldn't happen */ 517 sleep(5); 518 continue; 519 } 520 if (cc > 0) { 521 pcc -= cc; 522 pbp += cc; 523 } 524 } 525 } 526 } 527 528 cleanup() 529 { 530 char *p; 531 532 p = line + sizeof("/dev/") - 1; 533 if (logout(p)) 534 logwtmp(p, "", ""); 535 (void)chmod(line, 0666); 536 (void)chown(line, 0, 0); 537 *p = 'p'; 538 (void)chmod(line, 0666); 539 (void)chown(line, 0, 0); 540 shutdown(netf, 2); 541 exit(1); 542 } 543 544 fatal(f, msg) 545 int f; 546 char *msg; 547 { 548 char buf[BUFSIZ]; 549 550 buf[0] = '\01'; /* error indicator */ 551 (void) sprintf(buf + 1, "rlogind: %s.\r\n", msg); 552 (void) write(f, buf, strlen(buf)); 553 exit(1); 554 } 555 556 fatalperror(f, msg) 557 int f; 558 char *msg; 559 { 560 char buf[BUFSIZ]; 561 extern int sys_nerr; 562 extern char *sys_errlist[]; 563 564 if ((unsigned)errno < sys_nerr) 565 (void) sprintf(buf, "%s: %s", msg, sys_errlist[errno]); 566 else 567 (void) sprintf(buf, "%s: Error %d", msg, errno); 568 fatal(f, buf); 569 } 570 571 do_rlogin(host) 572 char *host; 573 { 574 575 getstr(rusername, sizeof(rusername), "remuser too long"); 576 getstr(lusername, sizeof(lusername), "locuser too long"); 577 getstr(term+ENVSIZE, sizeof(term)-ENVSIZE, "Terminal type too long"); 578 579 if (getuid()) 580 return(-1); 581 pwd = getpwnam(lusername); 582 if (pwd == NULL) 583 return(-1); 584 return(ruserok(host, SUPERUSER(pwd), rusername, lusername)); 585 } 586 587 588 getstr(buf, cnt, errmsg) 589 char *buf; 590 int cnt; 591 char *errmsg; 592 { 593 char c; 594 595 do { 596 if (read(0, &c, 1) != 1) 597 exit(1); 598 if (--cnt < 0) 599 fatal(1, errmsg); 600 *buf++ = c; 601 } while (c != 0); 602 } 603 604 extern char **environ; 605 606 setup_term(fd) 607 int fd; 608 { 609 register char *cp = index(term+ENVSIZE, '/'); 610 char *speed; 611 struct termios tt; 612 613 #ifndef notyet 614 tcgetattr(fd, &tt); 615 if (cp) { 616 *cp++ = '\0'; 617 speed = cp; 618 cp = index(speed, '/'); 619 if (cp) 620 *cp++ = '\0'; 621 cfsetspeed(&tt, atoi(speed)); 622 } 623 624 tt.c_iflag = TTYDEF_IFLAG; 625 tt.c_oflag = TTYDEF_OFLAG; 626 tt.c_lflag = TTYDEF_LFLAG; 627 tcsetattr(fd, TCSADFLUSH, &tt); 628 #else 629 if (cp) { 630 *cp++ = '\0'; 631 speed = cp; 632 cp = index(speed, '/'); 633 if (cp) 634 *cp++ = '\0'; 635 tcgetattr(fd, &tt); 636 cfsetspeed(&tt, atoi(speed)); 637 tcsetattr(fd, TCSADFLUSH, &tt); 638 } 639 #endif 640 641 env[0] = term; 642 env[1] = 0; 643 environ = env; 644 } 645 646 #ifdef KERBEROS 647 #define VERSION_SIZE 9 648 649 /* 650 * Do the remote kerberos login to the named host with the 651 * given inet address 652 * 653 * Return 0 on valid authorization 654 * Return -1 on valid authentication, no authorization 655 * Return >0 for error conditions 656 */ 657 do_krb_login(host, dest, encrypt) 658 char *host; 659 struct sockaddr_in *dest; 660 int encrypt; 661 { 662 int rc; 663 char instance[INST_SZ], version[VERSION_SIZE]; 664 long authopts = 0L; /* !mutual */ 665 struct sockaddr_in faddr; 666 667 if (getuid()) 668 return(KFAILURE); 669 670 kdata = (AUTH_DAT *) auth_buf; 671 ticket = (KTEXT) tick_buf; 672 strcpy(instance, "*"); 673 674 if (encrypt) { 675 rc = sizeof(faddr); 676 if (getsockname(0, &faddr, &rc)) 677 return(-1); 678 authopts = KOPT_DO_MUTUAL; 679 rc = krb_recvauth( 680 authopts, 0, 681 ticket, "rcmd", 682 instance, dest, &faddr, 683 kdata, "", schedule, version); 684 des_set_key(kdata->session, schedule); 685 686 } else { 687 rc = krb_recvauth( 688 authopts, 0, 689 ticket, "rcmd", 690 instance, dest, (struct sockaddr_in *) 0, 691 kdata, "", (bit_64 *) 0, version); 692 } 693 694 if (rc != KSUCCESS) 695 return(rc); 696 697 getstr(lusername, sizeof(lusername), "locuser"); 698 /* get the "cmd" in the rcmd protocol */ 699 getstr(term+ENVSIZE, sizeof(term)-ENVSIZE, "Terminal type"); 700 701 pwd = getpwnam(lusername); 702 if (pwd == NULL) 703 return(-1); 704 705 /* returns nonzero for no access */ 706 /* return(ruserok(host, SUPERUSER(pwd), rusername, lusername)); */ 707 if (kuserok(kdata,lusername) != 0) 708 return(-1); 709 710 return(0); 711 712 } 713 714 #endif /* KERBEROS */ 715 716 usage() 717 { 718 #ifdef KERBEROS 719 syslog(LOG_ERR, "usage: rlogind [-k | -v] [-a] [-l] [-n]"); 720 #else 721 syslog(LOG_ERR, "usage: rlogind [-a] [-l] [-n]"); 722 #endif 723 } 724 725 /* 726 * Check whether host h is in our local domain, 727 * defined as sharing the last two components of the domain part, 728 * or the entire domain part if the local domain has only one component. 729 * If either name is unqualified (contains no '.'), 730 * assume that the host is local, as it will be 731 * interpreted as such. 732 */ 733 local_domain(h) 734 char *h; 735 { 736 char localhost[MAXHOSTNAMELEN]; 737 char *p1, *p2, *topdomain(); 738 739 localhost[0] = 0; 740 (void) gethostname(localhost, sizeof(localhost)); 741 p1 = topdomain(localhost); 742 p2 = topdomain(h); 743 if (p1 == NULL || p2 == NULL || !strcasecmp(p1, p2)) 744 return(1); 745 return(0); 746 } 747 748 char * 749 topdomain(h) 750 char *h; 751 { 752 register char *p; 753 char *maybe = NULL; 754 int dots = 0; 755 756 for (p = h + strlen(h); p >= h; p--) { 757 if (*p == '.') { 758 if (++dots == 2) 759 return (p); 760 maybe = p; 761 } 762 } 763 return (maybe); 764 } 765