libexec/telnetd/telnetd.c

   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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#)telnetd.c        8.4 (Berkeley) 5/30/95
  30  * $FreeBSD: src/crypto/telnet/telnetd/telnetd.c,v 1.11.2.5 2002/04/13 10:59:09 markm Exp $
  31  */
  32
  33 #include "telnetd.h"
  34 #include "pathnames.h"
  35
  36 #include <sys/mman.h>
  37 #include <err.h>
  38 #include <libutil.h>
  39 #include <paths.h>
  40 #include <termcap.h>
  41 #include <utmp.h>
  42
  43 #include <arpa/inet.h>
  44
  45 #ifdef  AUTHENTICATION
  46 #include <libtelnet/auth.h>
  47 int     auth_level = 0;
  48 #endif
  49 #ifdef  ENCRYPTION
  50 #include <libtelnet/encrypt.h>
  51 #endif
  52 #include <libtelnet/misc.h>
  53
  54 char    remote_hostname[MAXHOSTNAMELEN];
  55 size_t  utmp_len = sizeof(remote_hostname) - 1;
  56 int     registerd_host_only = 0;
  57
  58
  59 /*
  60  * I/O data buffers,
  61  * pointers, and counters.
  62  */
  63 char    ptyibuf[BUFSIZ], *ptyip = ptyibuf;
  64 char    ptyibuf2[BUFSIZ];
  65
  66 int readstream(int, char *, int);
  67 void doit(struct sockaddr *) __dead2;
  68 int terminaltypeok(char *);
  69
  70 int     hostinfo = 1;                   /* do we print login banner? */
  71
  72 static int debug = 0;
  73 int keepalive = 1;
  74 const char *altlogin;
  75
  76 void startslave(char *, int, char *);
  77 extern void usage(void) __dead2;
  78 static void _gettermname(void);
  79
  80 /*
  81  * The string to pass to getopt().  We do it this way so
  82  * that only the actual options that we support will be
  83  * passed off to getopt().
  84  */
  85 char valid_opts[] = {
  86         'd', ':', 'h', 'k', 'n', 'p', ':', 'S', ':', 'u', ':', 'U',
  87         '4', '6',
  88 #ifdef  AUTHENTICATION
  89         'a', ':', 'X', ':',
  90 #endif
  91 #ifdef BFTPDAEMON
  92         'B',
  93 #endif
  94 #ifdef DIAGNOSTICS
  95         'D', ':',
  96 #endif
  97 #ifdef  ENCRYPTION
  98         'e', ':',
  99 #endif
 100 #ifdef  LINEMODE
 101         'l',
 102 #endif
 103         '\0'
 104 };
 105
 106 int family = AF_INET;
 107
 108 #ifndef MAXHOSTNAMELEN
 109 #define MAXHOSTNAMELEN 256
 110 #endif  /* MAXHOSTNAMELEN */
 111
 112 char *hostname;
 113 char host_name[MAXHOSTNAMELEN];
 114
 115 extern void telnet(int, int, char *) __dead2;
 116
 117 int level;
 118 char user_name[256];
 119
 120 int
 121 main(int argc, char *argv[])
 122 {
 123         struct sockaddr_storage from;
 124         int on = 1, fromlen;
 125         int ch;
 126 #if     defined(IPPROTO_IP) && defined(IP_TOS)
 127         int tos = -1;
 128 #endif
 129
 130         pfrontp = pbackp = ptyobuf;
 131         netip = netibuf;
 132         nfrontp = nbackp = netobuf;
 133 #ifdef  ENCRYPTION
 134         nclearto = 0;
 135 #endif  /* ENCRYPTION */
 136
 137         /*
 138          * This initialization causes linemode to default to a configuration
 139          * that works on all telnet clients, including the FreeBSD client.
 140          * This is not quite the same as the telnet client issuing a "mode
 141          * character" command, but has most of the same benefits, and is
 142          * preferable since some clients (like usofts) don't have the
 143          * mode character command anyway and linemode breaks things.
 144          * The most notable symptom of fix is that csh "set filec" operations
 145          * like <ESC> (filename completion) and ^D (choices) keys now work
 146          * in telnet sessions and can be used more than once on the same line.
 147          * CR/LF handling is also corrected in some termio modes.  This
 148          * change resolves problem reports bin/771 and bin/1037.
 149          */
 150
 151         linemode=1;     /*Default to mode that works on bulk of clients*/
 152
 153         while ((ch = getopt(argc, argv, valid_opts)) != -1) {
 154                 switch(ch) {
 155
 156 #ifdef  AUTHENTICATION
 157                 case 'a':
 158                         /*
 159                          * Check for required authentication level
 160                          */
 161                         if (strcmp(optarg, "debug") == 0) {
 162                                 extern int auth_debug_mode;
 163                                 auth_debug_mode = 1;
 164                         } else if (strcasecmp(optarg, "none") == 0) {
 165                                 auth_level = 0;
 166                         } else if (strcasecmp(optarg, "other") == 0) {
 167                                 auth_level = AUTH_OTHER;
 168                         } else if (strcasecmp(optarg, "user") == 0) {
 169                                 auth_level = AUTH_USER;
 170                         } else if (strcasecmp(optarg, "valid") == 0) {
 171                                 auth_level = AUTH_VALID;
 172                         } else if (strcasecmp(optarg, "off") == 0) {
 173                                 /*
 174                                  * This hack turns off authentication
 175                                  */
 176                                 auth_level = -1;
 177                         } else {
 178                                 warnx("unknown authorization level for -a");
 179                         }
 180                         break;
 181 #endif  /* AUTHENTICATION */
 182
 183 #ifdef BFTPDAEMON
 184                 case 'B':
 185                         bftpd++;
 186                         break;
 187 #endif /* BFTPDAEMON */
 188
 189                 case 'd':
 190                         if (strcmp(optarg, "ebug") == 0) {
 191                                 debug++;
 192                                 break;
 193                         }
 194                         usage();
 195                         /* NOTREACHED */
 196                         break;
 197
 198 #ifdef DIAGNOSTICS
 199                 case 'D':
 200                         /*
 201                          * Check for desired diagnostics capabilities.
 202                          */
 203                         if (!strcmp(optarg, "report")) {
 204                                 diagnostic |= TD_REPORT|TD_OPTIONS;
 205                         } else if (!strcmp(optarg, "exercise")) {
 206                                 diagnostic |= TD_EXERCISE;
 207                         } else if (!strcmp(optarg, "netdata")) {
 208                                 diagnostic |= TD_NETDATA;
 209                         } else if (!strcmp(optarg, "ptydata")) {
 210                                 diagnostic |= TD_PTYDATA;
 211                         } else if (!strcmp(optarg, "options")) {
 212                                 diagnostic |= TD_OPTIONS;
 213                         } else {
 214                                 usage();
 215                                 /* NOT REACHED */
 216                         }
 217                         break;
 218 #endif /* DIAGNOSTICS */
 219
 220 #ifdef  ENCRYPTION
 221                 case 'e':
 222                         if (strcmp(optarg, "debug") == 0) {
 223                                 extern int encrypt_debug_mode;
 224                                 encrypt_debug_mode = 1;
 225                                 break;
 226                         }
 227                         usage();
 228                         /* NOTREACHED */
 229                         break;
 230 #endif  /* ENCRYPTION */
 231
 232                 case 'h':
 233                         hostinfo = 0;
 234                         break;
 235
 236 #ifdef  LINEMODE
 237                 case 'l':
 238                         alwayslinemode = 1;
 239                         break;
 240 #endif  /* LINEMODE */
 241
 242                 case 'k':
 243 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
 244                         lmodetype = NO_AUTOKLUDGE;
 245 #else
 246                         /* ignore -k option if built without kludge linemode */
 247 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
 248                         break;
 249
 250                 case 'n':
 251                         keepalive = 0;
 252                         break;
 253
 254                 case 'p':
 255                         altlogin = optarg;
 256                         break;
 257
 258                 case 'S':
 259 #ifdef  HAS_GETTOS
 260                         if ((tos = parsetos(optarg, "tcp")) < 0)
 261                                 warnx("%s%s%s",
 262                                         "bad TOS argument '", optarg,
 263                                         "'; will try to use default TOS");
 264 #else
 265                         warnx("TOS option unavailable; -S flag not supported");
 266 #endif
 267                         break;
 268
 269                 case 'u':
 270                         utmp_len = (size_t)atoi(optarg);
 271                         if (utmp_len >= sizeof(remote_hostname))
 272                                 utmp_len = sizeof(remote_hostname) - 1;
 273                         break;
 274
 275                 case 'U':
 276                         registerd_host_only = 1;
 277                         break;
 278
 279 #ifdef  AUTHENTICATION
 280                 case 'X':
 281                         /*
 282                          * Check for invalid authentication types
 283                          */
 284                         auth_disable_name(optarg);
 285                         break;
 286 #endif  /* AUTHENTICATION */
 287
 288                 case '4':
 289                         family = AF_INET;
 290                         break;
 291
 292 #ifdef INET6
 293                 case '6':
 294                         family = AF_INET6;
 295                         break;
 296 #endif
 297
 298                 default:
 299                         warnx("%c: unknown option", ch);
 300                         /* FALLTHROUGH */
 301                 case '?':
 302                         usage();
 303                         /* NOTREACHED */
 304                 }
 305         }
 306
 307         argc -= optind;
 308         argv += optind;
 309
 310         if (debug) {
 311             int s, ns, foo, error;
 312             const char *service = "telnet";
 313             struct addrinfo hints, *res;
 314
 315             if (argc > 1) {
 316                 usage();
 317                 /* NOT REACHED */
 318             } else if (argc == 1)
 319                 service = *argv;
 320
 321             memset(&hints, 0, sizeof(hints));
 322             hints.ai_flags = AI_PASSIVE;
 323             hints.ai_family = family;
 324             hints.ai_socktype = SOCK_STREAM;
 325             hints.ai_protocol = 0;
 326             error = getaddrinfo(NULL, service, &hints, &res);
 327
 328             if (error) {
 329                 errx(1, "tcp/%s: %s\n", service, gai_strerror(error));
 330                 if (error == EAI_SYSTEM)
 331                     errx(1, "tcp/%s: %s\n", service, strerror(errno));
 332                 usage();
 333             }
 334
 335             s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
 336             if (s < 0)
 337                     err(1, "socket");
 338             (void) setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
 339                                 (char *)&on, sizeof(on));
 340             if (bind(s, res->ai_addr, res->ai_addrlen) < 0)
 341                 err(1, "bind");
 342             if (listen(s, 1) < 0)
 343                 err(1, "listen");
 344             foo = res->ai_addrlen;
 345             ns = accept(s, res->ai_addr, &foo);
 346             if (ns < 0)
 347                 err(1, "accept");
 348             (void) dup2(ns, 0);
 349             (void) close(ns);
 350             (void) close(s);
 351 #ifdef convex
 352         } else if (argc == 1) {
 353                 ; /* VOID*/             /* Just ignore the host/port name */
 354 #endif
 355         } else if (argc > 0) {
 356                 usage();
 357                 /* NOT REACHED */
 358         }
 359
 360         openlog("telnetd", LOG_PID | LOG_ODELAY, LOG_DAEMON);
 361         fromlen = sizeof (from);
 362         if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) {
 363                 warn("getpeername");
 364                 _exit(1);
 365         }
 366         if (keepalive &&
 367             setsockopt(0, SOL_SOCKET, SO_KEEPALIVE,
 368                         (char *)&on, sizeof (on)) < 0) {
 369                 syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
 370         }
 371
 372 #if     defined(IPPROTO_IP) && defined(IP_TOS)
 373         if (from.ss_family == AF_INET) {
 374 # if    defined(HAS_GETTOS)
 375                 struct tosent *tp;
 376                 if (tos < 0 && (tp = gettosbyname("telnet", "tcp")))
 377                         tos = tp->t_tos;
 378 # endif
 379                 if (tos < 0)
 380                         tos = 020;      /* Low Delay bit */
 381                 if (tos
 382                    && (setsockopt(0, IPPROTO_IP, IP_TOS,
 383                                   (char *)&tos, sizeof(tos)) < 0)
 384                    && (errno != ENOPROTOOPT) )
 385                         syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
 386         }
 387 #endif  /* defined(IPPROTO_IP) && defined(IP_TOS) */
 388         net = 0;
 389         doit((struct sockaddr *)&from);
 390         /* NOTREACHED */
 391         return(0);
 392 }  /* end of main */
 393
 394 void
 395 usage(void)
 396 {
 397         fprintf(stderr, "usage: telnetd");
 398 #ifdef  AUTHENTICATION
 399         fprintf(stderr, " [-a (debug|other|user|valid|off|none)]\n\t");
 400 #endif
 401 #ifdef BFTPDAEMON
 402         fprintf(stderr, " [-B]");
 403 #endif
 404         fprintf(stderr, " [-debug]");
 405 #ifdef DIAGNOSTICS
 406         fprintf(stderr, " [-D (options|report|exercise|netdata|ptydata)]\n\t");
 407 #endif
 408 #ifdef  AUTHENTICATION
 409         fprintf(stderr, " [-edebug]");
 410 #endif
 411         fprintf(stderr, " [-h]");
 412 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
 413         fprintf(stderr, " [-k]");
 414 #endif
 415 #ifdef LINEMODE
 416         fprintf(stderr, " [-l]");
 417 #endif
 418         fprintf(stderr, " [-n]");
 419         fprintf(stderr, "\n\t");
 420 #ifdef  HAS_GETTOS
 421         fprintf(stderr, " [-S tos]");
 422 #endif
 423 #ifdef  AUTHENTICATION
 424         fprintf(stderr, " [-X auth-type]");
 425 #endif
 426         fprintf(stderr, " [-u utmp_hostname_length] [-U]");
 427         fprintf(stderr, " [port]\n");
 428         exit(1);
 429 }
 430
 431 /*
 432  * getterminaltype
 433  *
 434  *      Ask the other end to send along its terminal type and speed.
 435  * Output is the variable terminaltype filled in.
 436  */
 437 static unsigned char ttytype_sbbuf[] = {
 438         IAC, SB, TELOPT_TTYPE, TELQUAL_SEND, IAC, SE
 439 };
 440
 441
 442 #ifndef AUTHENTICATION
 443 #define undef2 __unused
 444 #else
 445 #define undef2
 446 #endif
 447
 448 static int
 449 getterminaltype(char *name undef2)
 450 {
 451     int retval = -1;
 452
 453     settimer(baseline);
 454 #ifdef  AUTHENTICATION
 455     /*
 456      * Handle the Authentication option before we do anything else.
 457      */
 458     send_do(TELOPT_AUTHENTICATION, 1);
 459     while (his_will_wont_is_changing(TELOPT_AUTHENTICATION))
 460         ttloop();
 461     if (his_state_is_will(TELOPT_AUTHENTICATION)) {
 462         retval = auth_wait(name);
 463     }
 464 #endif
 465
 466 #ifdef  ENCRYPTION
 467     send_will(TELOPT_ENCRYPT, 1);
 468 #endif  /* ENCRYPTION */
 469     send_do(TELOPT_TTYPE, 1);
 470     send_do(TELOPT_TSPEED, 1);
 471     send_do(TELOPT_XDISPLOC, 1);
 472     send_do(TELOPT_NEW_ENVIRON, 1);
 473     send_do(TELOPT_OLD_ENVIRON, 1);
 474     while (
 475 #ifdef  ENCRYPTION
 476            his_do_dont_is_changing(TELOPT_ENCRYPT) ||
 477 #endif  /* ENCRYPTION */
 478            his_will_wont_is_changing(TELOPT_TTYPE) ||
 479            his_will_wont_is_changing(TELOPT_TSPEED) ||
 480            his_will_wont_is_changing(TELOPT_XDISPLOC) ||
 481            his_will_wont_is_changing(TELOPT_NEW_ENVIRON) ||
 482            his_will_wont_is_changing(TELOPT_OLD_ENVIRON)) {
 483         ttloop();
 484     }
 485 #ifdef  ENCRYPTION
 486     /*
 487      * Wait for the negotiation of what type of encryption we can
 488      * send with.  If autoencrypt is not set, this will just return.
 489      */
 490     if (his_state_is_will(TELOPT_ENCRYPT)) {
 491         encrypt_wait();
 492     }
 493 #endif  /* ENCRYPTION */
 494     if (his_state_is_will(TELOPT_TSPEED)) {
 495         static unsigned char sb[] =
 496                         { IAC, SB, TELOPT_TSPEED, TELQUAL_SEND, IAC, SE };
 497
 498         output_datalen(sb, sizeof sb);
 499         DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
 500     }
 501     if (his_state_is_will(TELOPT_XDISPLOC)) {
 502         static unsigned char sb[] =
 503                         { IAC, SB, TELOPT_XDISPLOC, TELQUAL_SEND, IAC, SE };
 504
 505         output_datalen(sb, sizeof sb);
 506         DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
 507     }
 508     if (his_state_is_will(TELOPT_NEW_ENVIRON)) {
 509         static unsigned char sb[] =
 510                         { IAC, SB, TELOPT_NEW_ENVIRON, TELQUAL_SEND, IAC, SE };
 511
 512         output_datalen(sb, sizeof sb);
 513         DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
 514     }
 515     else if (his_state_is_will(TELOPT_OLD_ENVIRON)) {
 516         static unsigned char sb[] =
 517                         { IAC, SB, TELOPT_OLD_ENVIRON, TELQUAL_SEND, IAC, SE };
 518
 519         output_datalen(sb, sizeof sb);
 520         DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
 521     }
 522     if (his_state_is_will(TELOPT_TTYPE)) {
 523
 524         output_datalen(ttytype_sbbuf, sizeof ttytype_sbbuf);
 525         DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2,
 526                                         sizeof ttytype_sbbuf - 2););
 527     }
 528     if (his_state_is_will(TELOPT_TSPEED)) {
 529         while (sequenceIs(tspeedsubopt, baseline))
 530             ttloop();
 531     }
 532     if (his_state_is_will(TELOPT_XDISPLOC)) {
 533         while (sequenceIs(xdisplocsubopt, baseline))
 534             ttloop();
 535     }
 536     if (his_state_is_will(TELOPT_NEW_ENVIRON)) {
 537         while (sequenceIs(environsubopt, baseline))
 538             ttloop();
 539     }
 540     if (his_state_is_will(TELOPT_OLD_ENVIRON)) {
 541         while (sequenceIs(oenvironsubopt, baseline))
 542             ttloop();
 543     }
 544     if (his_state_is_will(TELOPT_TTYPE)) {
 545         char first[256], last[256];
 546
 547         while (sequenceIs(ttypesubopt, baseline))
 548             ttloop();
 549
 550         /*
 551          * If the other side has already disabled the option, then
 552          * we have to just go with what we (might) have already gotten.
 553          */
 554         if (his_state_is_will(TELOPT_TTYPE) && !terminaltypeok(terminaltype)) {
 555             (void) strncpy(first, terminaltype, sizeof(first)-1);
 556             first[sizeof(first)-1] = '\0';
 557             for(;;) {
 558                 /*
 559                  * Save the unknown name, and request the next name.
 560                  */
 561                 (void) strncpy(last, terminaltype, sizeof(last)-1);
 562                 last[sizeof(last)-1] = '\0';
 563                 _gettermname();
 564                 if (terminaltypeok(terminaltype))
 565                     break;
 566                 if ((strncmp(last, terminaltype, sizeof(last)) == 0) ||
 567                     his_state_is_wont(TELOPT_TTYPE)) {
 568                     /*
 569                      * We've hit the end.  If this is the same as
 570                      * the first name, just go with it.
 571                      */
 572                     if (strncmp(first, terminaltype, sizeof(first)) == 0)
 573                         break;
 574                     /*
 575                      * Get the terminal name one more time, so that
 576                      * RFC1091 compliant telnets will cycle back to
 577                      * the start of the list.
 578                      */
 579                      _gettermname();
 580                     if (strncmp(first, terminaltype, sizeof(first)) != 0) {
 581                         (void) strncpy(terminaltype, first, TERMINAL_TYPE_SIZE-1);
 582                         terminaltype[TERMINAL_TYPE_SIZE-1] = '\0';
 583                     }
 584                     break;
 585                 }
 586             }
 587         }
 588     }
 589     return(retval);
 590 }  /* end of getterminaltype */
 591
 592 static void
 593 _gettermname(void)
 594 {
 595     /*
 596      * If the client turned off the option,
 597      * we can't send another request, so we
 598      * just return.
 599      */
 600     if (his_state_is_wont(TELOPT_TTYPE))
 601         return;
 602     settimer(baseline);
 603     output_datalen(ttytype_sbbuf, sizeof ttytype_sbbuf);
 604     DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2,
 605                                         sizeof ttytype_sbbuf - 2););
 606     while (sequenceIs(ttypesubopt, baseline))
 607         ttloop();
 608 }
 609
 610 int
 611 terminaltypeok(char *s)
 612 {
 613     char buf[1024];
 614
 615     if (terminaltype == NULL)
 616         return(1);
 617
 618     /*
 619      * tgetent() will return 1 if the type is known, and
 620      * 0 if it is not known.  If it returns -1, it couldn't
 621      * open the database.  But if we can't open the database,
 622      * it won't help to say we failed, because we won't be
 623      * able to verify anything else.  So, we treat -1 like 1.
 624      */
 625     if (tgetent(buf, s) == 0)
 626         return(0);
 627     return(1);
 628 }
 629
 630 /*
 631  * Get a pty, scan input lines.
 632  */
 633 void
 634 doit(struct sockaddr *who)
 635 {
 636         int err_; /* XXX */
 637         int ptynum;
 638
 639         /*
 640          * Find an available pty to use.
 641          */
 642 #ifndef convex
 643         pty = getpty(&ptynum);
 644         if (pty < 0)
 645                 fatal(net, "All network ports in use");
 646 #else
 647         for (;;) {
 648                 char *lp;
 649
 650                 if ((lp = getpty()) == NULL)
 651                         fatal(net, "Out of ptys");
 652
 653                 if ((pty = open(lp, 2)) >= 0) {
 654                         strlcpy(line,lp,sizeof(line));
 655                         line[5] = 't';
 656                         break;
 657                 }
 658         }
 659 #endif
 660
 661         /* get name of connected client */
 662         if (realhostname_sa(remote_hostname, sizeof(remote_hostname) - 1,
 663             who, who->sa_len) == HOSTNAME_INVALIDADDR && registerd_host_only)
 664                 fatal(net, "Couldn't resolve your address into a host name.\r\n\
 665         Please contact your net administrator");
 666         remote_hostname[sizeof(remote_hostname) - 1] = '\0';
 667
 668         trimdomain(remote_hostname, UT_HOSTSIZE);
 669         if (!isdigit(remote_hostname[0]) && strlen(remote_hostname) > utmp_len)
 670                 err_ = getnameinfo(who, who->sa_len, remote_hostname,
 671                                   sizeof(remote_hostname), NULL, 0,
 672                                   NI_NUMERICHOST|NI_WITHSCOPEID);
 673                 /* XXX: do 'err_' check */
 674
 675         (void) gethostname(host_name, sizeof(host_name) - 1);
 676         host_name[sizeof(host_name) - 1] = '\0';
 677         hostname = host_name;
 678
 679 #ifdef  AUTHENTICATION
 680 #ifdef  ENCRYPTION
 681 /* The above #ifdefs should actually be "or"'ed, not "and"'ed.
 682  * This is a byproduct of needing "#ifdef" and not "#if defined()"
 683  * for unifdef. XXX MarkM
 684  */
 685         auth_encrypt_init(hostname, remote_hostname, "TELNETD", 1);
 686 #endif
 687 #endif
 688
 689         init_env();
 690         /*
 691          * get terminal type.
 692          */
 693         *user_name = 0;
 694         level = getterminaltype(user_name);
 695         if (setenv("TERM", terminaltype ? terminaltype : "network", 1) == -1)
 696                 syslog(LOG_ERR, "setenv: cannot set TERM=%s: %m", terminaltype ? terminaltype : "network");
 697
 698         telnet(net, pty, remote_hostname);      /* begin server process */
 699
 700         /*NOTREACHED*/
 701 }  /* end of doit */
 702
 703 /*
 704  * Main loop.  Select from pty and network, and
 705  * hand data to telnet receiver finite state machine.
 706  */
 707 void
 708 telnet(int f, int p, char *host)
 709 {
 710         int on = 1;
 711 #define TABBUFSIZ       512
 712         char    defent[TABBUFSIZ];
 713         char    defstrs[TABBUFSIZ];
 714 #undef  TABBUFSIZ
 715         char *HE;
 716         char *HN;
 717         char *IM;
 718         int nfd;
 719
 720         /*
 721          * Initialize the slc mapping table.
 722          */
 723         get_slc_defaults();
 724
 725         /*
 726          * Do some tests where it is desireable to wait for a response.
 727          * Rather than doing them slowly, one at a time, do them all
 728          * at once.
 729          */
 730         if (my_state_is_wont(TELOPT_SGA))
 731                 send_will(TELOPT_SGA, 1);
 732         /*
 733          * Is the client side a 4.2 (NOT 4.3) system?  We need to know this
 734          * because 4.2 clients are unable to deal with TCP urgent data.
 735          *
 736          * To find out, we send out a "DO ECHO".  If the remote system
 737          * answers "WILL ECHO" it is probably a 4.2 client, and we note
 738          * that fact ("WILL ECHO" ==> that the client will echo what
 739          * WE, the server, sends it; it does NOT mean that the client will
 740          * echo the terminal input).
 741          */
 742         send_do(TELOPT_ECHO, 1);
 743
 744 #ifdef  LINEMODE
 745         if (his_state_is_wont(TELOPT_LINEMODE)) {
 746                 /* Query the peer for linemode support by trying to negotiate
 747                  * the linemode option.
 748                  */
 749                 linemode = 0;
 750                 editmode = 0;
 751                 send_do(TELOPT_LINEMODE, 1);  /* send do linemode */
 752         }
 753 #endif  /* LINEMODE */
 754
 755         /*
 756          * Send along a couple of other options that we wish to negotiate.
 757          */
 758         send_do(TELOPT_NAWS, 1);
 759         send_will(TELOPT_STATUS, 1);
 760         flowmode = 1;           /* default flow control state */
 761         restartany = -1;        /* uninitialized... */
 762         send_do(TELOPT_LFLOW, 1);
 763
 764         /*
 765          * Spin, waiting for a response from the DO ECHO.  However,
 766          * some REALLY DUMB telnets out there might not respond
 767          * to the DO ECHO.  So, we spin looking for NAWS, (most dumb
 768          * telnets so far seem to respond with WONT for a DO that
 769          * they don't understand...) because by the time we get the
 770          * response, it will already have processed the DO ECHO.
 771          * Kludge upon kludge.
 772          */
 773         while (his_will_wont_is_changing(TELOPT_NAWS))
 774                 ttloop();
 775
 776         /*
 777          * But...
 778          * The client might have sent a WILL NAWS as part of its
 779          * startup code; if so, we'll be here before we get the
 780          * response to the DO ECHO.  We'll make the assumption
 781          * that any implementation that understands about NAWS
 782          * is a modern enough implementation that it will respond
 783          * to our DO ECHO request; hence we'll do another spin
 784          * waiting for the ECHO option to settle down, which is
 785          * what we wanted to do in the first place...
 786          */
 787         if (his_want_state_is_will(TELOPT_ECHO) &&
 788             his_state_is_will(TELOPT_NAWS)) {
 789                 while (his_will_wont_is_changing(TELOPT_ECHO))
 790                         ttloop();
 791         }
 792         /*
 793          * On the off chance that the telnet client is broken and does not
 794          * respond to the DO ECHO we sent, (after all, we did send the
 795          * DO NAWS negotiation after the DO ECHO, and we won't get here
 796          * until a response to the DO NAWS comes back) simulate the
 797          * receipt of a will echo.  This will also send a WONT ECHO
 798          * to the client, since we assume that the client failed to
 799          * respond because it believes that it is already in DO ECHO
 800          * mode, which we do not want.
 801          */
 802         if (his_want_state_is_will(TELOPT_ECHO)) {
 803                 DIAG(TD_OPTIONS, output_data("td: simulating recv\r\n"));
 804                 willoption(TELOPT_ECHO);
 805         }
 806
 807         /*
 808          * Finally, to clean things up, we turn on our echo.  This
 809          * will break stupid 4.2 telnets out of local terminal echo.
 810          */
 811
 812         if (my_state_is_wont(TELOPT_ECHO))
 813                 send_will(TELOPT_ECHO, 1);
 814
 815         /*
 816          * Turn on packet mode
 817          */
 818         (void) ioctl(p, TIOCPKT, (char *)&on);
 819
 820 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
 821         /*
 822          * Continuing line mode support.  If client does not support
 823          * real linemode, attempt to negotiate kludge linemode by sending
 824          * the do timing mark sequence.
 825          */
 826         if (lmodetype < REAL_LINEMODE)
 827                 send_do(TELOPT_TM, 1);
 828 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
 829
 830         /*
 831          * Call telrcv() once to pick up anything received during
 832          * terminal type negotiation, 4.2/4.3 determination, and
 833          * linemode negotiation.
 834          */
 835         telrcv();
 836
 837         (void) ioctl(f, FIONBIO, (char *)&on);
 838         (void) ioctl(p, FIONBIO, (char *)&on);
 839
 840 #if     defined(SO_OOBINLINE)
 841         (void) setsockopt(net, SOL_SOCKET, SO_OOBINLINE,
 842                                 (char *)&on, sizeof on);
 843 #endif  /* defined(SO_OOBINLINE) */
 844
 845 #ifdef  SIGTSTP
 846         (void) signal(SIGTSTP, SIG_IGN);
 847 #endif
 848 #ifdef  SIGTTOU
 849         /*
 850          * Ignoring SIGTTOU keeps the kernel from blocking us
 851          * in ttioct() in /sys/tty.c.
 852          */
 853         (void) signal(SIGTTOU, SIG_IGN);
 854 #endif
 855
 856         (void) signal(SIGCHLD, cleanup);
 857
 858 #ifdef  TIOCNOTTY
 859         {
 860                 int t;
 861                 t = open(_PATH_TTY, O_RDWR);
 862                 if (t >= 0) {
 863                         (void) ioctl(t, TIOCNOTTY, NULL);
 864                         (void) close(t);
 865                 }
 866         }
 867 #endif
 868
 869         /*
 870          * Show banner that getty never gave.
 871          *
 872          * We put the banner in the pty input buffer.  This way, it
 873          * gets carriage return null processing, etc., just like all
 874          * other pty --> client data.
 875          */
 876
 877         if (getent(defent, "default") == 1) {
 878                 char *cp=defstrs;
 879
 880                 HE = Getstr("he", &cp);
 881                 HN = Getstr("hn", &cp);
 882                 IM = Getstr("im", &cp);
 883                 if (HN && *HN)
 884                         (void) strlcpy(host_name, HN, sizeof(host_name));
 885                 if (IM == NULL)
 886                         IM = strdup("");
 887         } else {
 888                 IM = strdup(DEFAULT_IM);
 889                 HE = NULL;
 890         }
 891         edithost(HE, host_name);
 892         if (hostinfo && *IM)
 893                 putf(IM, ptyibuf2);
 894
 895         if (pcc)
 896                 (void) strncat(ptyibuf2, ptyip, pcc+1);
 897         ptyip = ptyibuf2;
 898         pcc = strlen(ptyip);
 899 #ifdef  LINEMODE
 900         /*
 901          * Last check to make sure all our states are correct.
 902          */
 903         init_termbuf();
 904         localstat();
 905 #endif  /* LINEMODE */
 906
 907         DIAG(TD_REPORT, output_data("td: Entering processing loop\r\n"));
 908
 909         /*
 910          * Startup the login process on the slave side of the terminal
 911          * now.  We delay this until here to insure option negotiation
 912          * is complete.
 913          */
 914         startslave(host, level, user_name);
 915
 916         nfd = ((f > p) ? f : p) + 1;
 917         for (;;) {
 918                 fd_set ibits, obits, xbits;
 919                 int c;
 920
 921                 if (ncc < 0 && pcc < 0)
 922                         break;
 923
 924                 FD_ZERO(&ibits);
 925                 FD_ZERO(&obits);
 926                 FD_ZERO(&xbits);
 927                 /*
 928                  * Never look for input if there's still
 929                  * stuff in the corresponding output buffer
 930                  */
 931                 if (nfrontp - nbackp || pcc > 0) {
 932                         FD_SET(f, &obits);
 933                 } else {
 934                         FD_SET(p, &ibits);
 935                 }
 936                 if (pfrontp - pbackp || ncc > 0) {
 937                         FD_SET(p, &obits);
 938                 } else {
 939                         FD_SET(f, &ibits);
 940                 }
 941                 if (!SYNCHing) {
 942                         FD_SET(f, &xbits);
 943                 }
 944                 if ((c = select(nfd, &ibits, &obits, &xbits, NULL)) < 1) {
 945                         if (c == -1) {
 946                                 if (errno == EINTR) {
 947                                         continue;
 948                                 }
 949                         }
 950                         sleep(5);
 951                         continue;
 952                 }
 953
 954                 /*
 955                  * Any urgent data?
 956                  */
 957                 if (FD_ISSET(net, &xbits)) {
 958                     SYNCHing = 1;
 959                 }
 960
 961                 /*
 962                  * Something to read from the network...
 963                  */
 964                 if (FD_ISSET(net, &ibits)) {
 965 #if     !defined(SO_OOBINLINE)
 966                         /*
 967                          * In 4.2 (and 4.3 beta) systems, the
 968                          * OOB indication and data handling in the kernel
 969                          * is such that if two separate TCP Urgent requests
 970                          * come in, one byte of TCP data will be overlaid.
 971                          * This is fatal for Telnet, but we try to live
 972                          * with it.
 973                          *
 974                          * In addition, in 4.2 (and...), a special protocol
 975                          * is needed to pick up the TCP Urgent data in
 976                          * the correct sequence.
 977                          *
 978                          * What we do is:  if we think we are in urgent
 979                          * mode, we look to see if we are "at the mark".
 980                          * If we are, we do an OOB receive.  If we run
 981                          * this twice, we will do the OOB receive twice,
 982                          * but the second will fail, since the second
 983                          * time we were "at the mark", but there wasn't
 984                          * any data there (the kernel doesn't reset
 985                          * "at the mark" until we do a normal read).
 986                          * Once we've read the OOB data, we go ahead
 987                          * and do normal reads.
 988                          *
 989                          * There is also another problem, which is that
 990                          * since the OOB byte we read doesn't put us
 991                          * out of OOB state, and since that byte is most
 992                          * likely the TELNET DM (data mark), we would
 993                          * stay in the TELNET SYNCH (SYNCHing) state.
 994                          * So, clocks to the rescue.  If we've "just"
 995                          * received a DM, then we test for the
 996                          * presence of OOB data when the receive OOB
 997                          * fails (and AFTER we did the normal mode read
 998                          * to clear "at the mark").
 999                          */
1000                     if (SYNCHing) {
1001                         int atmark;
1002
1003                         (void) ioctl(net, SIOCATMARK, (char *)&atmark);
1004                         if (atmark) {
1005                             ncc = recv(net, netibuf, sizeof (netibuf), MSG_OOB);
1006                             if ((ncc == -1) && (errno == EINVAL)) {
1007                                 ncc = read(net, netibuf, sizeof (netibuf));
1008                                 if (sequenceIs(didnetreceive, gotDM)) {
1009                                     SYNCHing = stilloob(net);
1010                                 }
1011                             }
1012                         } else {
1013                             ncc = read(net, netibuf, sizeof (netibuf));
1014                         }
1015                     } else {
1016                         ncc = read(net, netibuf, sizeof (netibuf));
1017                     }
1018                     settimer(didnetreceive);
1019 #else   /* !defined(SO_OOBINLINE)) */
1020                     ncc = read(net, netibuf, sizeof (netibuf));
1021 #endif  /* !defined(SO_OOBINLINE)) */
1022                     if (ncc < 0 && errno == EWOULDBLOCK)
1023                         ncc = 0;
1024                     else {
1025                         if (ncc <= 0) {
1026                             break;
1027                         }
1028                         netip = netibuf;
1029                     }
1030                     DIAG((TD_REPORT | TD_NETDATA),
1031                         output_data("td: netread %d chars\r\n", ncc));
1032                     DIAG(TD_NETDATA, printdata("nd", netip, ncc));
1033                 }
1034
1035                 /*
1036                  * Something to read from the pty...
1037                  */
1038                 if (FD_ISSET(p, &ibits)) {
1039                         pcc = read(p, ptyibuf, BUFSIZ);
1040                         /*
1041                          * On some systems, if we try to read something
1042                          * off the master side before the slave side is
1043                          * opened, we get EIO.
1044                          */
1045                         if (pcc < 0 && (errno == EWOULDBLOCK ||
1046 #ifdef  EAGAIN
1047                                         errno == EAGAIN ||
1048 #endif
1049                                         errno == EIO)) {
1050                                 pcc = 0;
1051                         } else {
1052                                 if (pcc <= 0)
1053                                         break;
1054 #ifdef  LINEMODE
1055                                 /*
1056                                  * If ioctl from pty, pass it through net
1057                                  */
1058                                 if (ptyibuf[0] & TIOCPKT_IOCTL) {
1059                                         copy_termbuf(ptyibuf+1, pcc-1);
1060                                         localstat();
1061                                         pcc = 1;
1062                                 }
1063 #endif  /* LINEMODE */
1064                                 if (ptyibuf[0] & TIOCPKT_FLUSHWRITE) {
1065                                         netclear();     /* clear buffer back */
1066 #ifndef NO_URGENT
1067                                         /*
1068                                          * There are client telnets on some
1069                                          * operating systems get screwed up
1070                                          * royally if we send them urgent
1071                                          * mode data.
1072                                          */
1073                                         output_data("%c%c", IAC, DM);
1074                                         neturg = nfrontp-1; /* off by one XXX */
1075                                         DIAG(TD_OPTIONS,
1076                                             printoption("td: send IAC", DM));
1077
1078 #endif
1079                                 }
1080                                 if (his_state_is_will(TELOPT_LFLOW) &&
1081                                     (ptyibuf[0] &
1082                                      (TIOCPKT_NOSTOP|TIOCPKT_DOSTOP))) {
1083                                         int newflow =
1084                                             ptyibuf[0] & TIOCPKT_DOSTOP ? 1 : 0;
1085                                         if (newflow != flowmode) {
1086                                                 flowmode = newflow;
1087                                                 output_data("%c%c%c%c%c%c",
1088                                                         IAC, SB, TELOPT_LFLOW,
1089                                                         flowmode ? LFLOW_ON
1090                                                                  : LFLOW_OFF,
1091                                                         IAC, SE);
1092                                                 DIAG(TD_OPTIONS, printsub('>',
1093                                                     (unsigned char *)nfrontp-4,
1094                                                     4););
1095                                         }
1096                                 }
1097                                 pcc--;
1098                                 ptyip = ptyibuf+1;
1099                         }
1100                 }
1101
1102                 while (pcc > 0) {
1103                         if ((&netobuf[BUFSIZ] - nfrontp) < 2)
1104                                 break;
1105                         c = *ptyip++ & 0377, pcc--;
1106                         if (c == IAC)
1107                                 output_data("%c", c);
1108                         output_data("%c", c);
1109                         if ((c == '\r') && (my_state_is_wont(TELOPT_BINARY))) {
1110                                 if (pcc > 0 && ((*ptyip & 0377) == '\n')) {
1111                                         output_data("%c", *ptyip++ & 0377);
1112                                         pcc--;
1113                                 } else
1114                                         output_data("%c", '\0');
1115                         }
1116                 }
1117
1118                 if (FD_ISSET(f, &obits) && (nfrontp - nbackp) > 0)
1119                         netflush();
1120                 if (ncc > 0)
1121                         telrcv();
1122                 if (FD_ISSET(p, &obits) && (pfrontp - pbackp) > 0)
1123                         ptyflush();
1124         }
1125         cleanup(0);
1126 }  /* end of telnet */
1127
1128 #ifndef TCSIG
1129 # ifdef TIOCSIG
1130 #  define TCSIG TIOCSIG
1131 # endif
1132 #endif
1133
1134 /*
1135  * Send interrupt to process on other side of pty.
1136  * If it is in raw mode, just write NULL;
1137  * otherwise, write intr char.
1138  */
1139 void
1140 interrupt(void)
1141 {
1142         ptyflush();     /* half-hearted */
1143
1144 #ifdef  TCSIG
1145         (void) ioctl(pty, TCSIG, (char *)SIGINT);
1146 #else   /* TCSIG */
1147         init_termbuf();
1148         *pfrontp++ = slctab[SLC_IP].sptr ?
1149                         (unsigned char)*slctab[SLC_IP].sptr : '\177';
1150 #endif  /* TCSIG */
1151 }
1152
1153 /*
1154  * Send quit to process on other side of pty.
1155  * If it is in raw mode, just write NULL;
1156  * otherwise, write quit char.
1157  */
1158 void
1159 sendbrk(void)
1160 {
1161         ptyflush();     /* half-hearted */
1162 #ifdef  TCSIG
1163         (void) ioctl(pty, TCSIG, (char *)SIGQUIT);
1164 #else   /* TCSIG */
1165         init_termbuf();
1166         *pfrontp++ = slctab[SLC_ABORT].sptr ?
1167                         (unsigned char)*slctab[SLC_ABORT].sptr : '\034';
1168 #endif  /* TCSIG */
1169 }
1170
1171 void
1172 sendsusp(void)
1173 {
1174 #ifdef  SIGTSTP
1175         ptyflush();     /* half-hearted */
1176 # ifdef TCSIG
1177         (void) ioctl(pty, TCSIG, (char *)SIGTSTP);
1178 # else  /* TCSIG */
1179         *pfrontp++ = slctab[SLC_SUSP].sptr ?
1180                         (unsigned char)*slctab[SLC_SUSP].sptr : '\032';
1181 # endif /* TCSIG */
1182 #endif  /* SIGTSTP */
1183 }
1184
1185 /*
1186  * When we get an AYT, if ^T is enabled, use that.  Otherwise,
1187  * just send back "[Yes]".
1188  */
1189 void
1190 recv_ayt(void)
1191 {
1192 #if     defined(SIGINFO) && defined(TCSIG)
1193         if (slctab[SLC_AYT].sptr && *slctab[SLC_AYT].sptr != _POSIX_VDISABLE) {
1194                 (void) ioctl(pty, TCSIG, (char *)SIGINFO);
1195                 return;
1196         }
1197 #endif
1198         output_data("\r\n[Yes]\r\n");
1199 }
1200
1201 void
1202 doeof(void)
1203 {
1204         init_termbuf();
1205
1206 #if     defined(LINEMODE) && defined(USE_TERMIO) && (VEOF == VMIN)
1207         if (!tty_isediting()) {
1208                 extern char oldeofc;
1209                 *pfrontp++ = oldeofc;
1210                 return;
1211         }
1212 #endif
1213         *pfrontp++ = slctab[SLC_EOF].sptr ?
1214                         (unsigned char)*slctab[SLC_EOF].sptr : '\004';
1215 }