telnetd.c revision 302408
1/* 2 * Copyright (c) 1989, 1993 3 * The Regents of the University of California. 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#if 0 35#ifndef lint 36static const char sccsid[] = "@(#)telnetd.c 8.4 (Berkeley) 5/30/95"; 37#endif 38#endif 39#include <sys/cdefs.h> 40__FBSDID("$FreeBSD: stable/11/contrib/telnet/telnetd/telnetd.c 262679 2014-03-02 03:34:06Z marcel $"); 41 42#include "telnetd.h" 43#include "pathnames.h" 44 45#include <sys/mman.h> 46#include <err.h> 47#include <libutil.h> 48#include <paths.h> 49#include <termcap.h> 50 51#include <arpa/inet.h> 52 53#ifdef AUTHENTICATION 54#include <libtelnet/auth.h> 55int auth_level = 0; 56#endif 57#ifdef ENCRYPTION 58#include <libtelnet/encrypt.h> 59#endif 60#include <libtelnet/misc.h> 61 62char remote_hostname[MAXHOSTNAMELEN]; 63size_t utmp_len = sizeof(remote_hostname) - 1; 64int registerd_host_only = 0; 65 66 67/* 68 * I/O data buffers, 69 * pointers, and counters. 70 */ 71char ptyibuf[BUFSIZ], *ptyip = ptyibuf; 72char ptyibuf2[BUFSIZ]; 73 74int readstream(int, char *, int); 75void doit(struct sockaddr *); 76int terminaltypeok(char *); 77 78int hostinfo = 1; /* do we print login banner? */ 79 80static int debug = 0; 81int keepalive = 1; 82const char *altlogin; 83 84void doit(struct sockaddr *); 85int terminaltypeok(char *); 86void startslave(char *, int, char *); 87extern void usage(void); 88static void _gettermname(void); 89 90/* 91 * The string to pass to getopt(). We do it this way so 92 * that only the actual options that we support will be 93 * passed off to getopt(). 94 */ 95char valid_opts[] = { 96 'd', ':', 'h', 'k', 'n', 'p', ':', 'S', ':', 'u', ':', 'U', 97 '4', '6', 98#ifdef AUTHENTICATION 99 'a', ':', 'X', ':', 100#endif 101#ifdef BFTPDAEMON 102 'B', 103#endif 104#ifdef DIAGNOSTICS 105 'D', ':', 106#endif 107#ifdef ENCRYPTION 108 'e', ':', 109#endif 110#ifdef LINEMODE 111 'l', 112#endif 113 '\0' 114}; 115 116int family = AF_INET; 117 118#ifndef MAXHOSTNAMELEN 119#define MAXHOSTNAMELEN 256 120#endif /* MAXHOSTNAMELEN */ 121 122char *hostname; 123char host_name[MAXHOSTNAMELEN]; 124 125extern void telnet(int, int, char *); 126 127int level; 128char user_name[256]; 129 130int 131main(int argc, char *argv[]) 132{ 133 u_long ultmp; 134 struct sockaddr_storage from; 135 int on = 1, fromlen; 136 int ch; 137#if defined(IPPROTO_IP) && defined(IP_TOS) 138 int tos = -1; 139#endif 140 char *ep; 141 142 pfrontp = pbackp = ptyobuf; 143 netip = netibuf; 144 nfrontp = nbackp = netobuf; 145#ifdef ENCRYPTION 146 nclearto = 0; 147#endif /* ENCRYPTION */ 148 149 /* 150 * This initialization causes linemode to default to a configuration 151 * that works on all telnet clients, including the FreeBSD client. 152 * This is not quite the same as the telnet client issuing a "mode 153 * character" command, but has most of the same benefits, and is 154 * preferable since some clients (like usofts) don't have the 155 * mode character command anyway and linemode breaks things. 156 * The most notable symptom of fix is that csh "set filec" operations 157 * like <ESC> (filename completion) and ^D (choices) keys now work 158 * in telnet sessions and can be used more than once on the same line. 159 * CR/LF handling is also corrected in some termio modes. This 160 * change resolves problem reports bin/771 and bin/1037. 161 */ 162 163 linemode=1; /*Default to mode that works on bulk of clients*/ 164 165 while ((ch = getopt(argc, argv, valid_opts)) != -1) { 166 switch(ch) { 167 168#ifdef AUTHENTICATION 169 case 'a': 170 /* 171 * Check for required authentication level 172 */ 173 if (strcmp(optarg, "debug") == 0) { 174 extern int auth_debug_mode; 175 auth_debug_mode = 1; 176 } else if (strcasecmp(optarg, "none") == 0) { 177 auth_level = 0; 178 } else if (strcasecmp(optarg, "other") == 0) { 179 auth_level = AUTH_OTHER; 180 } else if (strcasecmp(optarg, "user") == 0) { 181 auth_level = AUTH_USER; 182 } else if (strcasecmp(optarg, "valid") == 0) { 183 auth_level = AUTH_VALID; 184 } else if (strcasecmp(optarg, "off") == 0) { 185 /* 186 * This hack turns off authentication 187 */ 188 auth_level = -1; 189 } else { 190 warnx("unknown authorization level for -a"); 191 } 192 break; 193#endif /* AUTHENTICATION */ 194 195#ifdef BFTPDAEMON 196 case 'B': 197 bftpd++; 198 break; 199#endif /* BFTPDAEMON */ 200 201 case 'd': 202 if (strcmp(optarg, "ebug") == 0) { 203 debug++; 204 break; 205 } 206 usage(); 207 /* NOTREACHED */ 208 break; 209 210#ifdef DIAGNOSTICS 211 case 'D': 212 /* 213 * Check for desired diagnostics capabilities. 214 */ 215 if (!strcmp(optarg, "report")) { 216 diagnostic |= TD_REPORT|TD_OPTIONS; 217 } else if (!strcmp(optarg, "exercise")) { 218 diagnostic |= TD_EXERCISE; 219 } else if (!strcmp(optarg, "netdata")) { 220 diagnostic |= TD_NETDATA; 221 } else if (!strcmp(optarg, "ptydata")) { 222 diagnostic |= TD_PTYDATA; 223 } else if (!strcmp(optarg, "options")) { 224 diagnostic |= TD_OPTIONS; 225 } else { 226 usage(); 227 /* NOT REACHED */ 228 } 229 break; 230#endif /* DIAGNOSTICS */ 231 232#ifdef ENCRYPTION 233 case 'e': 234 if (strcmp(optarg, "debug") == 0) { 235 extern int encrypt_debug_mode; 236 encrypt_debug_mode = 1; 237 break; 238 } 239 usage(); 240 /* NOTREACHED */ 241 break; 242#endif /* ENCRYPTION */ 243 244 case 'h': 245 hostinfo = 0; 246 break; 247 248#ifdef LINEMODE 249 case 'l': 250 alwayslinemode = 1; 251 break; 252#endif /* LINEMODE */ 253 254 case 'k': 255#if defined(LINEMODE) && defined(KLUDGELINEMODE) 256 lmodetype = NO_AUTOKLUDGE; 257#else 258 /* ignore -k option if built without kludge linemode */ 259#endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */ 260 break; 261 262 case 'n': 263 keepalive = 0; 264 break; 265 266 case 'p': 267 altlogin = optarg; 268 break; 269 270 case 'S': 271#ifdef HAS_GETTOS 272 if ((tos = parsetos(optarg, "tcp")) < 0) 273 warnx("%s%s%s", 274 "bad TOS argument '", optarg, 275 "'; will try to use default TOS"); 276#else 277#define MAXTOS 255 278 ultmp = strtoul(optarg, &ep, 0); 279 if (*ep || ep == optarg || ultmp > MAXTOS) 280 warnx("%s%s%s", 281 "bad TOS argument '", optarg, 282 "'; will try to use default TOS"); 283 else 284 tos = ultmp; 285#endif 286 break; 287 288 case 'u': 289 utmp_len = (size_t)atoi(optarg); 290 if (utmp_len >= sizeof(remote_hostname)) 291 utmp_len = sizeof(remote_hostname) - 1; 292 break; 293 294 case 'U': 295 registerd_host_only = 1; 296 break; 297 298#ifdef AUTHENTICATION 299 case 'X': 300 /* 301 * Check for invalid authentication types 302 */ 303 auth_disable_name(optarg); 304 break; 305#endif /* AUTHENTICATION */ 306 307 case '4': 308 family = AF_INET; 309 break; 310 311#ifdef INET6 312 case '6': 313 family = AF_INET6; 314 break; 315#endif 316 317 default: 318 warnx("%c: unknown option", ch); 319 /* FALLTHROUGH */ 320 case '?': 321 usage(); 322 /* NOTREACHED */ 323 } 324 } 325 326 argc -= optind; 327 argv += optind; 328 329 if (debug) { 330 int s, ns, foo, error; 331 const char *service = "telnet"; 332 struct addrinfo hints, *res; 333 334 if (argc > 1) { 335 usage(); 336 /* NOT REACHED */ 337 } else if (argc == 1) 338 service = *argv; 339 340 memset(&hints, 0, sizeof(hints)); 341 hints.ai_flags = AI_PASSIVE; 342 hints.ai_family = family; 343 hints.ai_socktype = SOCK_STREAM; 344 hints.ai_protocol = 0; 345 error = getaddrinfo(NULL, service, &hints, &res); 346 347 if (error) { 348 errx(1, "tcp/%s: %s\n", service, gai_strerror(error)); 349 if (error == EAI_SYSTEM) 350 errx(1, "tcp/%s: %s\n", service, strerror(errno)); 351 usage(); 352 } 353 354 s = socket(res->ai_family, res->ai_socktype, res->ai_protocol); 355 if (s < 0) 356 err(1, "socket"); 357 (void) setsockopt(s, SOL_SOCKET, SO_REUSEADDR, 358 (char *)&on, sizeof(on)); 359 if (debug > 1) 360 (void) setsockopt(s, SOL_SOCKET, SO_DEBUG, 361 (char *)&on, sizeof(on)); 362 if (bind(s, res->ai_addr, res->ai_addrlen) < 0) 363 err(1, "bind"); 364 if (listen(s, 1) < 0) 365 err(1, "listen"); 366 foo = res->ai_addrlen; 367 ns = accept(s, res->ai_addr, &foo); 368 if (ns < 0) 369 err(1, "accept"); 370 (void) setsockopt(ns, SOL_SOCKET, SO_DEBUG, 371 (char *)&on, sizeof(on)); 372 (void) dup2(ns, 0); 373 (void) close(ns); 374 (void) close(s); 375#ifdef convex 376 } else if (argc == 1) { 377 ; /* VOID*/ /* Just ignore the host/port name */ 378#endif 379 } else if (argc > 0) { 380 usage(); 381 /* NOT REACHED */ 382 } 383 384 openlog("telnetd", LOG_PID | LOG_ODELAY, LOG_DAEMON); 385 fromlen = sizeof (from); 386 if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) { 387 warn("getpeername"); 388 _exit(1); 389 } 390 if (keepalive && 391 setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, 392 (char *)&on, sizeof (on)) < 0) { 393 syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m"); 394 } 395 396#if defined(IPPROTO_IP) && defined(IP_TOS) 397 if (from.ss_family == AF_INET) { 398# if defined(HAS_GETTOS) 399 struct tosent *tp; 400 if (tos < 0 && (tp = gettosbyname("telnet", "tcp"))) 401 tos = tp->t_tos; 402# endif 403 if (tos < 0) 404 tos = 020; /* Low Delay bit */ 405 if (tos 406 && (setsockopt(0, IPPROTO_IP, IP_TOS, 407 (char *)&tos, sizeof(tos)) < 0) 408 && (errno != ENOPROTOOPT) ) 409 syslog(LOG_WARNING, "setsockopt (IP_TOS): %m"); 410 } 411#endif /* defined(IPPROTO_IP) && defined(IP_TOS) */ 412 net = 0; 413 doit((struct sockaddr *)&from); 414 /* NOTREACHED */ 415 return(0); 416} /* end of main */ 417 418 void 419usage() 420{ 421 fprintf(stderr, "usage: telnetd"); 422#ifdef AUTHENTICATION 423 fprintf(stderr, 424 " [-4] [-6] [-a (debug|other|user|valid|off|none)]\n\t"); 425#endif 426#ifdef BFTPDAEMON 427 fprintf(stderr, " [-B]"); 428#endif 429 fprintf(stderr, " [-debug]"); 430#ifdef DIAGNOSTICS 431 fprintf(stderr, " [-D (options|report|exercise|netdata|ptydata)]\n\t"); 432#endif 433#ifdef AUTHENTICATION 434 fprintf(stderr, " [-edebug]"); 435#endif 436 fprintf(stderr, " [-h]"); 437#if defined(LINEMODE) && defined(KLUDGELINEMODE) 438 fprintf(stderr, " [-k]"); 439#endif 440#ifdef LINEMODE 441 fprintf(stderr, " [-l]"); 442#endif 443 fprintf(stderr, " [-n]"); 444 fprintf(stderr, "\n\t"); 445#ifdef HAS_GETTOS 446 fprintf(stderr, " [-S tos]"); 447#endif 448#ifdef AUTHENTICATION 449 fprintf(stderr, " [-X auth-type]"); 450#endif 451 fprintf(stderr, " [-u utmp_hostname_length] [-U]"); 452 fprintf(stderr, " [port]\n"); 453 exit(1); 454} 455 456/* 457 * getterminaltype 458 * 459 * Ask the other end to send along its terminal type and speed. 460 * Output is the variable terminaltype filled in. 461 */ 462static unsigned char ttytype_sbbuf[] = { 463 IAC, SB, TELOPT_TTYPE, TELQUAL_SEND, IAC, SE 464}; 465 466 467#ifndef AUTHENTICATION 468#define undef2 __unused 469#else 470#define undef2 471#endif 472 473static int 474getterminaltype(char *name undef2) 475{ 476 int retval = -1; 477 478 settimer(baseline); 479#ifdef AUTHENTICATION 480 /* 481 * Handle the Authentication option before we do anything else. 482 */ 483 if (auth_level >= 0) { 484 send_do(TELOPT_AUTHENTICATION, 1); 485 while (his_will_wont_is_changing(TELOPT_AUTHENTICATION)) 486 ttloop(); 487 if (his_state_is_will(TELOPT_AUTHENTICATION)) { 488 retval = auth_wait(name); 489 } 490 } 491#endif 492 493#ifdef ENCRYPTION 494 send_will(TELOPT_ENCRYPT, 1); 495#endif /* ENCRYPTION */ 496 send_do(TELOPT_TTYPE, 1); 497 send_do(TELOPT_TSPEED, 1); 498 send_do(TELOPT_XDISPLOC, 1); 499 send_do(TELOPT_NEW_ENVIRON, 1); 500 send_do(TELOPT_OLD_ENVIRON, 1); 501 while ( 502#ifdef ENCRYPTION 503 his_do_dont_is_changing(TELOPT_ENCRYPT) || 504#endif /* ENCRYPTION */ 505 his_will_wont_is_changing(TELOPT_TTYPE) || 506 his_will_wont_is_changing(TELOPT_TSPEED) || 507 his_will_wont_is_changing(TELOPT_XDISPLOC) || 508 his_will_wont_is_changing(TELOPT_NEW_ENVIRON) || 509 his_will_wont_is_changing(TELOPT_OLD_ENVIRON)) { 510 ttloop(); 511 } 512#ifdef ENCRYPTION 513 /* 514 * Wait for the negotiation of what type of encryption we can 515 * send with. If autoencrypt is not set, this will just return. 516 */ 517 if (his_state_is_will(TELOPT_ENCRYPT)) { 518 encrypt_wait(); 519 } 520#endif /* ENCRYPTION */ 521 if (his_state_is_will(TELOPT_TSPEED)) { 522 static unsigned char sb[] = 523 { IAC, SB, TELOPT_TSPEED, TELQUAL_SEND, IAC, SE }; 524 525 output_datalen(sb, sizeof sb); 526 DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2);); 527 } 528 if (his_state_is_will(TELOPT_XDISPLOC)) { 529 static unsigned char sb[] = 530 { IAC, SB, TELOPT_XDISPLOC, TELQUAL_SEND, IAC, SE }; 531 532 output_datalen(sb, sizeof sb); 533 DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2);); 534 } 535 if (his_state_is_will(TELOPT_NEW_ENVIRON)) { 536 static unsigned char sb[] = 537 { IAC, SB, TELOPT_NEW_ENVIRON, TELQUAL_SEND, IAC, SE }; 538 539 output_datalen(sb, sizeof sb); 540 DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2);); 541 } 542 else if (his_state_is_will(TELOPT_OLD_ENVIRON)) { 543 static unsigned char sb[] = 544 { IAC, SB, TELOPT_OLD_ENVIRON, TELQUAL_SEND, IAC, SE }; 545 546 output_datalen(sb, sizeof sb); 547 DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2);); 548 } 549 if (his_state_is_will(TELOPT_TTYPE)) { 550 551 output_datalen(ttytype_sbbuf, sizeof ttytype_sbbuf); 552 DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2, 553 sizeof ttytype_sbbuf - 2);); 554 } 555 if (his_state_is_will(TELOPT_TSPEED)) { 556 while (sequenceIs(tspeedsubopt, baseline)) 557 ttloop(); 558 } 559 if (his_state_is_will(TELOPT_XDISPLOC)) { 560 while (sequenceIs(xdisplocsubopt, baseline)) 561 ttloop(); 562 } 563 if (his_state_is_will(TELOPT_NEW_ENVIRON)) { 564 while (sequenceIs(environsubopt, baseline)) 565 ttloop(); 566 } 567 if (his_state_is_will(TELOPT_OLD_ENVIRON)) { 568 while (sequenceIs(oenvironsubopt, baseline)) 569 ttloop(); 570 } 571 if (his_state_is_will(TELOPT_TTYPE)) { 572 char first[256], last[256]; 573 574 while (sequenceIs(ttypesubopt, baseline)) 575 ttloop(); 576 577 /* 578 * If the other side has already disabled the option, then 579 * we have to just go with what we (might) have already gotten. 580 */ 581 if (his_state_is_will(TELOPT_TTYPE) && !terminaltypeok(terminaltype)) { 582 (void) strncpy(first, terminaltype, sizeof(first)-1); 583 first[sizeof(first)-1] = '\0'; 584 for(;;) { 585 /* 586 * Save the unknown name, and request the next name. 587 */ 588 (void) strncpy(last, terminaltype, sizeof(last)-1); 589 last[sizeof(last)-1] = '\0'; 590 _gettermname(); 591 if (terminaltypeok(terminaltype)) 592 break; 593 if ((strncmp(last, terminaltype, sizeof(last)) == 0) || 594 his_state_is_wont(TELOPT_TTYPE)) { 595 /* 596 * We've hit the end. If this is the same as 597 * the first name, just go with it. 598 */ 599 if (strncmp(first, terminaltype, sizeof(first)) == 0) 600 break; 601 /* 602 * Get the terminal name one more time, so that 603 * RFC1091 compliant telnets will cycle back to 604 * the start of the list. 605 */ 606 _gettermname(); 607 if (strncmp(first, terminaltype, sizeof(first)) != 0) { 608 (void) strncpy(terminaltype, first, sizeof(terminaltype)-1); 609 terminaltype[sizeof(terminaltype)-1] = '\0'; 610 } 611 break; 612 } 613 } 614 } 615 } 616 return(retval); 617} /* end of getterminaltype */ 618 619static void 620_gettermname(void) 621{ 622 /* 623 * If the client turned off the option, 624 * we can't send another request, so we 625 * just return. 626 */ 627 if (his_state_is_wont(TELOPT_TTYPE)) 628 return; 629 settimer(baseline); 630 output_datalen(ttytype_sbbuf, sizeof ttytype_sbbuf); 631 DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2, 632 sizeof ttytype_sbbuf - 2);); 633 while (sequenceIs(ttypesubopt, baseline)) 634 ttloop(); 635} 636 637int 638terminaltypeok(char *s) 639{ 640 char buf[1024]; 641 642 if (terminaltype == NULL) 643 return(1); 644 645 /* 646 * tgetent() will return 1 if the type is known, and 647 * 0 if it is not known. If it returns -1, it couldn't 648 * open the database. But if we can't open the database, 649 * it won't help to say we failed, because we won't be 650 * able to verify anything else. So, we treat -1 like 1. 651 */ 652 if (tgetent(buf, s) == 0) 653 return(0); 654 return(1); 655} 656 657/* 658 * Get a pty, scan input lines. 659 */ 660void 661doit(struct sockaddr *who) 662{ 663 int err_; /* XXX */ 664 int ptynum; 665 666 /* 667 * Find an available pty to use. 668 */ 669#ifndef convex 670 pty = getpty(&ptynum); 671 if (pty < 0) 672 fatal(net, "All network ports in use"); 673#else 674 for (;;) { 675 char *lp; 676 677 if ((lp = getpty()) == NULL) 678 fatal(net, "Out of ptys"); 679 680 if ((pty = open(lp, 2)) >= 0) { 681 strlcpy(line,lp,sizeof(line)); 682 line[5] = 't'; 683 break; 684 } 685 } 686#endif 687 688 /* get name of connected client */ 689 if (realhostname_sa(remote_hostname, sizeof(remote_hostname) - 1, 690 who, who->sa_len) == HOSTNAME_INVALIDADDR && registerd_host_only) 691 fatal(net, "Couldn't resolve your address into a host name.\r\n\ 692 Please contact your net administrator"); 693 remote_hostname[sizeof(remote_hostname) - 1] = '\0'; 694 695 if (!isdigit(remote_hostname[0]) && strlen(remote_hostname) > utmp_len) 696 err_ = getnameinfo(who, who->sa_len, remote_hostname, 697 sizeof(remote_hostname), NULL, 0, 698 NI_NUMERICHOST); 699 /* XXX: do 'err_' check */ 700 701 (void) gethostname(host_name, sizeof(host_name) - 1); 702 host_name[sizeof(host_name) - 1] = '\0'; 703 hostname = host_name; 704 705#ifdef AUTHENTICATION 706#ifdef ENCRYPTION 707/* The above #ifdefs should actually be "or"'ed, not "and"'ed. 708 * This is a byproduct of needing "#ifdef" and not "#if defined()" 709 * for unifdef. XXX MarkM 710 */ 711 auth_encrypt_init(hostname, remote_hostname, "TELNETD", 1); 712#endif 713#endif 714 715 init_env(); 716 /* 717 * get terminal type. 718 */ 719 *user_name = 0; 720 level = getterminaltype(user_name); 721 setenv("TERM", terminaltype ? terminaltype : "network", 1); 722 723 telnet(net, pty, remote_hostname); /* begin server process */ 724 725 /*NOTREACHED*/ 726} /* end of doit */ 727 728/* 729 * Main loop. Select from pty and network, and 730 * hand data to telnet receiver finite state machine. 731 */ 732void 733telnet(int f, int p, char *host) 734{ 735 int on = 1; 736#define TABBUFSIZ 512 737 char defent[TABBUFSIZ]; 738 char defstrs[TABBUFSIZ]; 739#undef TABBUFSIZ 740 char *HE; 741 char *HN; 742 char *IM; 743 char *IF; 744 char *if_buf; 745 int if_fd = -1; 746 struct stat statbuf; 747 int nfd; 748 749 /* 750 * Initialize the slc mapping table. 751 */ 752 get_slc_defaults(); 753 754 /* 755 * Do some tests where it is desireable to wait for a response. 756 * Rather than doing them slowly, one at a time, do them all 757 * at once. 758 */ 759 if (my_state_is_wont(TELOPT_SGA)) 760 send_will(TELOPT_SGA, 1); 761 /* 762 * Is the client side a 4.2 (NOT 4.3) system? We need to know this 763 * because 4.2 clients are unable to deal with TCP urgent data. 764 * 765 * To find out, we send out a "DO ECHO". If the remote system 766 * answers "WILL ECHO" it is probably a 4.2 client, and we note 767 * that fact ("WILL ECHO" ==> that the client will echo what 768 * WE, the server, sends it; it does NOT mean that the client will 769 * echo the terminal input). 770 */ 771 send_do(TELOPT_ECHO, 1); 772 773#ifdef LINEMODE 774 if (his_state_is_wont(TELOPT_LINEMODE)) { 775 /* Query the peer for linemode support by trying to negotiate 776 * the linemode option. 777 */ 778 linemode = 0; 779 editmode = 0; 780 send_do(TELOPT_LINEMODE, 1); /* send do linemode */ 781 } 782#endif /* LINEMODE */ 783 784 /* 785 * Send along a couple of other options that we wish to negotiate. 786 */ 787 send_do(TELOPT_NAWS, 1); 788 send_will(TELOPT_STATUS, 1); 789 flowmode = 1; /* default flow control state */ 790 restartany = -1; /* uninitialized... */ 791 send_do(TELOPT_LFLOW, 1); 792 793 /* 794 * Spin, waiting for a response from the DO ECHO. However, 795 * some REALLY DUMB telnets out there might not respond 796 * to the DO ECHO. So, we spin looking for NAWS, (most dumb 797 * telnets so far seem to respond with WONT for a DO that 798 * they don't understand...) because by the time we get the 799 * response, it will already have processed the DO ECHO. 800 * Kludge upon kludge. 801 */ 802 while (his_will_wont_is_changing(TELOPT_NAWS)) 803 ttloop(); 804 805 /* 806 * But... 807 * The client might have sent a WILL NAWS as part of its 808 * startup code; if so, we'll be here before we get the 809 * response to the DO ECHO. We'll make the assumption 810 * that any implementation that understands about NAWS 811 * is a modern enough implementation that it will respond 812 * to our DO ECHO request; hence we'll do another spin 813 * waiting for the ECHO option to settle down, which is 814 * what we wanted to do in the first place... 815 */ 816 if (his_want_state_is_will(TELOPT_ECHO) && 817 his_state_is_will(TELOPT_NAWS)) { 818 while (his_will_wont_is_changing(TELOPT_ECHO)) 819 ttloop(); 820 } 821 /* 822 * On the off chance that the telnet client is broken and does not 823 * respond to the DO ECHO we sent, (after all, we did send the 824 * DO NAWS negotiation after the DO ECHO, and we won't get here 825 * until a response to the DO NAWS comes back) simulate the 826 * receipt of a will echo. This will also send a WONT ECHO 827 * to the client, since we assume that the client failed to 828 * respond because it believes that it is already in DO ECHO 829 * mode, which we do not want. 830 */ 831 if (his_want_state_is_will(TELOPT_ECHO)) { 832 DIAG(TD_OPTIONS, output_data("td: simulating recv\r\n")); 833 willoption(TELOPT_ECHO); 834 } 835 836 /* 837 * Finally, to clean things up, we turn on our echo. This 838 * will break stupid 4.2 telnets out of local terminal echo. 839 */ 840 841 if (my_state_is_wont(TELOPT_ECHO)) 842 send_will(TELOPT_ECHO, 1); 843 844 /* 845 * Turn on packet mode 846 */ 847 (void) ioctl(p, TIOCPKT, (char *)&on); 848 849#if defined(LINEMODE) && defined(KLUDGELINEMODE) 850 /* 851 * Continuing line mode support. If client does not support 852 * real linemode, attempt to negotiate kludge linemode by sending 853 * the do timing mark sequence. 854 */ 855 if (lmodetype < REAL_LINEMODE) 856 send_do(TELOPT_TM, 1); 857#endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */ 858 859 /* 860 * Call telrcv() once to pick up anything received during 861 * terminal type negotiation, 4.2/4.3 determination, and 862 * linemode negotiation. 863 */ 864 telrcv(); 865 866 (void) ioctl(f, FIONBIO, (char *)&on); 867 (void) ioctl(p, FIONBIO, (char *)&on); 868 869#if defined(SO_OOBINLINE) 870 (void) setsockopt(net, SOL_SOCKET, SO_OOBINLINE, 871 (char *)&on, sizeof on); 872#endif /* defined(SO_OOBINLINE) */ 873 874#ifdef SIGTSTP 875 (void) signal(SIGTSTP, SIG_IGN); 876#endif 877#ifdef SIGTTOU 878 /* 879 * Ignoring SIGTTOU keeps the kernel from blocking us 880 * in ttioct() in /sys/tty.c. 881 */ 882 (void) signal(SIGTTOU, SIG_IGN); 883#endif 884 885 (void) signal(SIGCHLD, cleanup); 886 887#ifdef TIOCNOTTY 888 { 889 int t; 890 t = open(_PATH_TTY, O_RDWR); 891 if (t >= 0) { 892 (void) ioctl(t, TIOCNOTTY, (char *)0); 893 (void) close(t); 894 } 895 } 896#endif 897 898 /* 899 * Show banner that getty never gave. 900 * 901 * We put the banner in the pty input buffer. This way, it 902 * gets carriage return null processing, etc., just like all 903 * other pty --> client data. 904 */ 905 906 if (getent(defent, "default") == 1) { 907 char *cp=defstrs; 908 909 HE = Getstr("he", &cp); 910 HN = Getstr("hn", &cp); 911 IM = Getstr("im", &cp); 912 IF = Getstr("if", &cp); 913 if (HN && *HN) 914 (void) strlcpy(host_name, HN, sizeof(host_name)); 915 if (IF) { 916 if_fd = open(IF, O_RDONLY, 000); 917 IM = 0; 918 } 919 if (IM == 0) 920 IM = strdup(""); 921 } else { 922 IM = strdup(DEFAULT_IM); 923 HE = 0; 924 } 925 edithost(HE, host_name); 926 if (hostinfo && *IM) 927 putf(IM, ptyibuf2); 928 if (IF && if_fd != -1) { 929 if (fstat(if_fd, &statbuf) != -1 && statbuf.st_size > 0) { 930 if_buf = (char *) mmap (0, statbuf.st_size, 931 PROT_READ, 0, if_fd, 0); 932 if (if_buf != MAP_FAILED) { 933 putf(if_buf, ptyibuf2); 934 munmap(if_buf, statbuf.st_size); 935 } 936 } 937 close (if_fd); 938 } 939 940 if (pcc) 941 (void) strncat(ptyibuf2, ptyip, pcc+1); 942 ptyip = ptyibuf2; 943 pcc = strlen(ptyip); 944#ifdef LINEMODE 945 /* 946 * Last check to make sure all our states are correct. 947 */ 948 init_termbuf(); 949 localstat(); 950#endif /* LINEMODE */ 951 952 DIAG(TD_REPORT, output_data("td: Entering processing loop\r\n")); 953 954 /* 955 * Startup the login process on the slave side of the terminal 956 * now. We delay this until here to insure option negotiation 957 * is complete. 958 */ 959 startslave(host, level, user_name); 960 961 nfd = ((f > p) ? f : p) + 1; 962 for (;;) { 963 fd_set ibits, obits, xbits; 964 int c; 965 966 if (ncc < 0 && pcc < 0) 967 break; 968 969 FD_ZERO(&ibits); 970 FD_ZERO(&obits); 971 FD_ZERO(&xbits); 972 /* 973 * Never look for input if there's still 974 * stuff in the corresponding output buffer 975 */ 976 if (nfrontp - nbackp || pcc > 0) { 977 FD_SET(f, &obits); 978 } else { 979 FD_SET(p, &ibits); 980 } 981 if (pfrontp - pbackp || ncc > 0) { 982 FD_SET(p, &obits); 983 } else { 984 FD_SET(f, &ibits); 985 } 986 if (!SYNCHing) { 987 FD_SET(f, &xbits); 988 } 989 if ((c = select(nfd, &ibits, &obits, &xbits, 990 (struct timeval *)0)) < 1) { 991 if (c == -1) { 992 if (errno == EINTR) { 993 continue; 994 } 995 } 996 sleep(5); 997 continue; 998 } 999 1000 /* 1001 * Any urgent data? 1002 */ 1003 if (FD_ISSET(net, &xbits)) { 1004 SYNCHing = 1; 1005 } 1006 1007 /* 1008 * Something to read from the network... 1009 */ 1010 if (FD_ISSET(net, &ibits)) { 1011#if !defined(SO_OOBINLINE) 1012 /* 1013 * In 4.2 (and 4.3 beta) systems, the 1014 * OOB indication and data handling in the kernel 1015 * is such that if two separate TCP Urgent requests 1016 * come in, one byte of TCP data will be overlaid. 1017 * This is fatal for Telnet, but we try to live 1018 * with it. 1019 * 1020 * In addition, in 4.2 (and...), a special protocol 1021 * is needed to pick up the TCP Urgent data in 1022 * the correct sequence. 1023 * 1024 * What we do is: if we think we are in urgent 1025 * mode, we look to see if we are "at the mark". 1026 * If we are, we do an OOB receive. If we run 1027 * this twice, we will do the OOB receive twice, 1028 * but the second will fail, since the second 1029 * time we were "at the mark", but there wasn't 1030 * any data there (the kernel doesn't reset 1031 * "at the mark" until we do a normal read). 1032 * Once we've read the OOB data, we go ahead 1033 * and do normal reads. 1034 * 1035 * There is also another problem, which is that 1036 * since the OOB byte we read doesn't put us 1037 * out of OOB state, and since that byte is most 1038 * likely the TELNET DM (data mark), we would 1039 * stay in the TELNET SYNCH (SYNCHing) state. 1040 * So, clocks to the rescue. If we've "just" 1041 * received a DM, then we test for the 1042 * presence of OOB data when the receive OOB 1043 * fails (and AFTER we did the normal mode read 1044 * to clear "at the mark"). 1045 */ 1046 if (SYNCHing) { 1047 int atmark; 1048 1049 (void) ioctl(net, SIOCATMARK, (char *)&atmark); 1050 if (atmark) { 1051 ncc = recv(net, netibuf, sizeof (netibuf), MSG_OOB); 1052 if ((ncc == -1) && (errno == EINVAL)) { 1053 ncc = read(net, netibuf, sizeof (netibuf)); 1054 if (sequenceIs(didnetreceive, gotDM)) { 1055 SYNCHing = stilloob(net); 1056 } 1057 } 1058 } else { 1059 ncc = read(net, netibuf, sizeof (netibuf)); 1060 } 1061 } else { 1062 ncc = read(net, netibuf, sizeof (netibuf)); 1063 } 1064 settimer(didnetreceive); 1065#else /* !defined(SO_OOBINLINE)) */ 1066 ncc = read(net, netibuf, sizeof (netibuf)); 1067#endif /* !defined(SO_OOBINLINE)) */ 1068 if (ncc < 0 && errno == EWOULDBLOCK) 1069 ncc = 0; 1070 else { 1071 if (ncc <= 0) { 1072 break; 1073 } 1074 netip = netibuf; 1075 } 1076 DIAG((TD_REPORT | TD_NETDATA), 1077 output_data("td: netread %d chars\r\n", ncc)); 1078 DIAG(TD_NETDATA, printdata("nd", netip, ncc)); 1079 } 1080 1081 /* 1082 * Something to read from the pty... 1083 */ 1084 if (FD_ISSET(p, &ibits)) { 1085 pcc = read(p, ptyibuf, BUFSIZ); 1086 /* 1087 * On some systems, if we try to read something 1088 * off the master side before the slave side is 1089 * opened, we get EIO. 1090 */ 1091 if (pcc < 0 && (errno == EWOULDBLOCK || 1092#ifdef EAGAIN 1093 errno == EAGAIN || 1094#endif 1095 errno == EIO)) { 1096 pcc = 0; 1097 } else { 1098 if (pcc <= 0) 1099 break; 1100#ifdef LINEMODE 1101 /* 1102 * If ioctl from pty, pass it through net 1103 */ 1104 if (ptyibuf[0] & TIOCPKT_IOCTL) { 1105 copy_termbuf(ptyibuf+1, pcc-1); 1106 localstat(); 1107 pcc = 1; 1108 } 1109#endif /* LINEMODE */ 1110 if (ptyibuf[0] & TIOCPKT_FLUSHWRITE) { 1111 netclear(); /* clear buffer back */ 1112#ifndef NO_URGENT 1113 /* 1114 * There are client telnets on some 1115 * operating systems get screwed up 1116 * royally if we send them urgent 1117 * mode data. 1118 */ 1119 output_data("%c%c", IAC, DM); 1120 neturg = nfrontp-1; /* off by one XXX */ 1121 DIAG(TD_OPTIONS, 1122 printoption("td: send IAC", DM)); 1123 1124#endif 1125 } 1126 if (his_state_is_will(TELOPT_LFLOW) && 1127 (ptyibuf[0] & 1128 (TIOCPKT_NOSTOP|TIOCPKT_DOSTOP))) { 1129 int newflow = 1130 ptyibuf[0] & TIOCPKT_DOSTOP ? 1 : 0; 1131 if (newflow != flowmode) { 1132 flowmode = newflow; 1133 output_data("%c%c%c%c%c%c", 1134 IAC, SB, TELOPT_LFLOW, 1135 flowmode ? LFLOW_ON 1136 : LFLOW_OFF, 1137 IAC, SE); 1138 DIAG(TD_OPTIONS, printsub('>', 1139 (unsigned char *)nfrontp-4, 1140 4);); 1141 } 1142 } 1143 pcc--; 1144 ptyip = ptyibuf+1; 1145 } 1146 } 1147 1148 while (pcc > 0) { 1149 if ((&netobuf[BUFSIZ] - nfrontp) < 2) 1150 break; 1151 c = *ptyip++ & 0377, pcc--; 1152 if (c == IAC) 1153 output_data("%c", c); 1154 output_data("%c", c); 1155 if ((c == '\r') && (my_state_is_wont(TELOPT_BINARY))) { 1156 if (pcc > 0 && ((*ptyip & 0377) == '\n')) { 1157 output_data("%c", *ptyip++ & 0377); 1158 pcc--; 1159 } else 1160 output_data("%c", '\0'); 1161 } 1162 } 1163 1164 if (FD_ISSET(f, &obits) && (nfrontp - nbackp) > 0) 1165 netflush(); 1166 if (ncc > 0) 1167 telrcv(); 1168 if (FD_ISSET(p, &obits) && (pfrontp - pbackp) > 0) 1169 ptyflush(); 1170 } 1171 cleanup(0); 1172} /* end of telnet */ 1173 1174#ifndef TCSIG 1175# ifdef TIOCSIG 1176# define TCSIG TIOCSIG 1177# endif 1178#endif 1179 1180/* 1181 * Send interrupt to process on other side of pty. 1182 * If it is in raw mode, just write NULL; 1183 * otherwise, write intr char. 1184 */ 1185void 1186interrupt(void) 1187{ 1188 ptyflush(); /* half-hearted */ 1189 1190#ifdef TCSIG 1191 (void) ioctl(pty, TCSIG, SIGINT); 1192#else /* TCSIG */ 1193 init_termbuf(); 1194 *pfrontp++ = slctab[SLC_IP].sptr ? 1195 (unsigned char)*slctab[SLC_IP].sptr : '\177'; 1196#endif /* TCSIG */ 1197} 1198 1199/* 1200 * Send quit to process on other side of pty. 1201 * If it is in raw mode, just write NULL; 1202 * otherwise, write quit char. 1203 */ 1204void 1205sendbrk(void) 1206{ 1207 ptyflush(); /* half-hearted */ 1208#ifdef TCSIG 1209 (void) ioctl(pty, TCSIG, SIGQUIT); 1210#else /* TCSIG */ 1211 init_termbuf(); 1212 *pfrontp++ = slctab[SLC_ABORT].sptr ? 1213 (unsigned char)*slctab[SLC_ABORT].sptr : '\034'; 1214#endif /* TCSIG */ 1215} 1216 1217void 1218sendsusp(void) 1219{ 1220#ifdef SIGTSTP 1221 ptyflush(); /* half-hearted */ 1222# ifdef TCSIG 1223 (void) ioctl(pty, TCSIG, SIGTSTP); 1224# else /* TCSIG */ 1225 *pfrontp++ = slctab[SLC_SUSP].sptr ? 1226 (unsigned char)*slctab[SLC_SUSP].sptr : '\032'; 1227# endif /* TCSIG */ 1228#endif /* SIGTSTP */ 1229} 1230 1231/* 1232 * When we get an AYT, if ^T is enabled, use that. Otherwise, 1233 * just send back "[Yes]". 1234 */ 1235void 1236recv_ayt(void) 1237{ 1238#if defined(SIGINFO) && defined(TCSIG) 1239 if (slctab[SLC_AYT].sptr && *slctab[SLC_AYT].sptr != _POSIX_VDISABLE) { 1240 (void) ioctl(pty, TCSIG, SIGINFO); 1241 return; 1242 } 1243#endif 1244 output_data("\r\n[Yes]\r\n"); 1245} 1246 1247void 1248doeof(void) 1249{ 1250 init_termbuf(); 1251 1252#if defined(LINEMODE) && defined(USE_TERMIO) && (VEOF == VMIN) 1253 if (!tty_isediting()) { 1254 extern char oldeofc; 1255 *pfrontp++ = oldeofc; 1256 return; 1257 } 1258#endif 1259 *pfrontp++ = slctab[SLC_EOF].sptr ? 1260 (unsigned char)*slctab[SLC_EOF].sptr : '\004'; 1261} 1262