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
36 static const char sccsid[] = "@(#)telnetd.c 8.4 (Berkeley) 5/30/95";
37 #endif
38 #endif
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
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>
55 int auth_level = 0;
56 #endif
57 #ifdef ENCRYPTION
58 #include <libtelnet/encrypt.h>
59 #endif
60 #include <libtelnet/misc.h>
61
62 char remote_hostname[MAXHOSTNAMELEN];
63 size_t utmp_len = sizeof(remote_hostname) - 1;
64 int registerd_host_only = 0;
65
66
67 /*
68 * I/O data buffers,
69 * pointers, and counters.
70 */
71 char ptyibuf[BUFSIZ], *ptyip = ptyibuf;
72 char ptyibuf2[BUFSIZ];
73
74 int readstream(int, char *, int);
75 void doit(struct sockaddr *);
76 int terminaltypeok(char *);
77
78 int hostinfo = 1; /* do we print login banner? */
79
80 static int debug = 0;
81 int keepalive = 1;
82 const char *altlogin;
83
84 void doit(struct sockaddr *);
85 int terminaltypeok(char *);
86 void startslave(char *, int, char *);
87 extern void usage(void);
88 static 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 */
95 char 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
116 int family = AF_INET;
117
118 #ifndef MAXHOSTNAMELEN
119 #define MAXHOSTNAMELEN 256
120 #endif /* MAXHOSTNAMELEN */
121
122 char *hostname;
123 char host_name[MAXHOSTNAMELEN];
124
125 extern void telnet(int, int, char *);
126
127 int level;
128 char user_name[256];
129
130 int
main(int argc,char * argv[])131 main(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
usage()419 usage()
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 */
462 static 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
473 static int
getterminaltype(char * name undef2)474 getterminaltype(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
619 static void
_gettermname(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
637 int
terminaltypeok(char * s)638 terminaltypeok(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 */
660 void
doit(struct sockaddr * who)661 doit(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 */
732 void
telnet(int f,int p,char * host)733 telnet(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 */
1185 void
interrupt(void)1186 interrupt(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 */
1204 void
sendbrk(void)1205 sendbrk(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
1217 void
sendsusp(void)1218 sendsusp(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 */
1235 void
recv_ayt(void)1236 recv_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
1247 void
doeof(void)1248 doeof(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