telnetd.c revision 351433 
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
30#if 0
31#ifndef lint
32static const char sccsid[] = "@(#)telnetd.c	8.4 (Berkeley) 5/30/95";
33#endif
34#endif
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD: stable/11/contrib/telnet/telnetd/telnetd.c 351433 2019-08-23 17:43:41Z emaste $");
37
38#include "telnetd.h"
39#include "pathnames.h"
40
41#include <sys/mman.h>
42#include <err.h>
43#include <libutil.h>
44#include <paths.h>
45#include <termcap.h>
46
47#include <arpa/inet.h>
48
49#ifdef	AUTHENTICATION
50#include <libtelnet/auth.h>
51int	auth_level = 0;
52#endif
53#ifdef	ENCRYPTION
54#include <libtelnet/encrypt.h>
55#endif
56#include <libtelnet/misc.h>
57
58char	remote_hostname[MAXHOSTNAMELEN];
59size_t	utmp_len = sizeof(remote_hostname) - 1;
60int	registerd_host_only = 0;
61
62
63/*
64 * I/O data buffers,
65 * pointers, and counters.
66 */
67char	ptyibuf[BUFSIZ], *ptyip = ptyibuf;
68char	ptyibuf2[BUFSIZ];
69
70int readstream(int, char *, int);
71void doit(struct sockaddr *);
72int terminaltypeok(char *);
73
74int	hostinfo = 1;			/* do we print login banner? */
75
76static int debug = 0;
77int keepalive = 1;
78const char *altlogin;
79
80void doit(struct sockaddr *);
81int terminaltypeok(char *);
82void startslave(char *, int, char *);
83extern void usage(void);
84static void _gettermname(void);
85
86/*
87 * The string to pass to getopt().  We do it this way so
88 * that only the actual options that we support will be
89 * passed off to getopt().
90 */
91char valid_opts[] = {
92	'd', ':', 'h', 'k', 'n', 'p', ':', 'S', ':', 'u', ':', 'U',
93	'4', '6',
94#ifdef	AUTHENTICATION
95	'a', ':', 'X', ':',
96#endif
97#ifdef BFTPDAEMON
98	'B',
99#endif
100#ifdef DIAGNOSTICS
101	'D', ':',
102#endif
103#ifdef	ENCRYPTION
104	'e', ':',
105#endif
106#ifdef	LINEMODE
107	'l',
108#endif
109	'\0'
110};
111
112int family = AF_INET;
113
114#ifndef	MAXHOSTNAMELEN
115#define	MAXHOSTNAMELEN 256
116#endif	/* MAXHOSTNAMELEN */
117
118char *hostname;
119char host_name[MAXHOSTNAMELEN];
120
121extern void telnet(int, int, char *);
122
123int level;
124char user_name[256];
125
126int
127main(int argc, char *argv[])
128{
129	u_long ultmp;
130	struct sockaddr_storage from;
131	int on = 1, fromlen;
132	int ch;
133#if	defined(IPPROTO_IP) && defined(IP_TOS)
134	int tos = -1;
135#endif
136	char *ep;
137
138	pfrontp = pbackp = ptyobuf;
139	netip = netibuf;
140	nfrontp = nbackp = netobuf;
141#ifdef	ENCRYPTION
142	nclearto = 0;
143#endif	/* ENCRYPTION */
144
145	/*
146	 * This initialization causes linemode to default to a configuration
147	 * that works on all telnet clients, including the FreeBSD client.
148	 * This is not quite the same as the telnet client issuing a "mode
149	 * character" command, but has most of the same benefits, and is
150	 * preferable since some clients (like usofts) don't have the
151	 * mode character command anyway and linemode breaks things.
152	 * The most notable symptom of fix is that csh "set filec" operations
153	 * like <ESC> (filename completion) and ^D (choices) keys now work
154	 * in telnet sessions and can be used more than once on the same line.
155	 * CR/LF handling is also corrected in some termio modes.  This
156	 * change resolves problem reports bin/771 and bin/1037.
157	 */
158
159	linemode=1;	/*Default to mode that works on bulk of clients*/
160
161	while ((ch = getopt(argc, argv, valid_opts)) != -1) {
162		switch(ch) {
163
164#ifdef	AUTHENTICATION
165		case 'a':
166			/*
167			 * Check for required authentication level
168			 */
169			if (strcmp(optarg, "debug") == 0) {
170				extern int auth_debug_mode;
171				auth_debug_mode = 1;
172			} else if (strcasecmp(optarg, "none") == 0) {
173				auth_level = 0;
174			} else if (strcasecmp(optarg, "other") == 0) {
175				auth_level = AUTH_OTHER;
176			} else if (strcasecmp(optarg, "user") == 0) {
177				auth_level = AUTH_USER;
178			} else if (strcasecmp(optarg, "valid") == 0) {
179				auth_level = AUTH_VALID;
180			} else if (strcasecmp(optarg, "off") == 0) {
181				/*
182				 * This hack turns off authentication
183				 */
184				auth_level = -1;
185			} else {
186				warnx("unknown authorization level for -a");
187			}
188			break;
189#endif	/* AUTHENTICATION */
190
191#ifdef BFTPDAEMON
192		case 'B':
193			bftpd++;
194			break;
195#endif /* BFTPDAEMON */
196
197		case 'd':
198			if (strcmp(optarg, "ebug") == 0) {
199				debug++;
200				break;
201			}
202			usage();
203			/* NOTREACHED */
204			break;
205
206#ifdef DIAGNOSTICS
207		case 'D':
208			/*
209			 * Check for desired diagnostics capabilities.
210			 */
211			if (!strcmp(optarg, "report")) {
212				diagnostic |= TD_REPORT|TD_OPTIONS;
213			} else if (!strcmp(optarg, "exercise")) {
214				diagnostic |= TD_EXERCISE;
215			} else if (!strcmp(optarg, "netdata")) {
216				diagnostic |= TD_NETDATA;
217			} else if (!strcmp(optarg, "ptydata")) {
218				diagnostic |= TD_PTYDATA;
219			} else if (!strcmp(optarg, "options")) {
220				diagnostic |= TD_OPTIONS;
221			} else {
222				usage();
223				/* NOT REACHED */
224			}
225			break;
226#endif /* DIAGNOSTICS */
227
228#ifdef	ENCRYPTION
229		case 'e':
230			if (strcmp(optarg, "debug") == 0) {
231				extern int encrypt_debug_mode;
232				encrypt_debug_mode = 1;
233				break;
234			}
235			usage();
236			/* NOTREACHED */
237			break;
238#endif	/* ENCRYPTION */
239
240		case 'h':
241			hostinfo = 0;
242			break;
243
244#ifdef	LINEMODE
245		case 'l':
246			alwayslinemode = 1;
247			break;
248#endif	/* LINEMODE */
249
250		case 'k':
251#if	defined(LINEMODE) && defined(KLUDGELINEMODE)
252			lmodetype = NO_AUTOKLUDGE;
253#else
254			/* ignore -k option if built without kludge linemode */
255#endif	/* defined(LINEMODE) && defined(KLUDGELINEMODE) */
256			break;
257
258		case 'n':
259			keepalive = 0;
260			break;
261
262		case 'p':
263			altlogin = optarg;
264			break;
265
266		case 'S':
267#ifdef	HAS_GETTOS
268			if ((tos = parsetos(optarg, "tcp")) < 0)
269				warnx("%s%s%s",
270					"bad TOS argument '", optarg,
271					"'; will try to use default TOS");
272#else
273#define	MAXTOS	255
274			ultmp = strtoul(optarg, &ep, 0);
275			if (*ep || ep == optarg || ultmp > MAXTOS)
276				warnx("%s%s%s",
277					"bad TOS argument '", optarg,
278					"'; will try to use default TOS");
279			else
280				tos = ultmp;
281#endif
282			break;
283
284		case 'u':
285			utmp_len = (size_t)atoi(optarg);
286			if (utmp_len >= sizeof(remote_hostname))
287				utmp_len = sizeof(remote_hostname) - 1;
288			break;
289
290		case 'U':
291			registerd_host_only = 1;
292			break;
293
294#ifdef	AUTHENTICATION
295		case 'X':
296			/*
297			 * Check for invalid authentication types
298			 */
299			auth_disable_name(optarg);
300			break;
301#endif	/* AUTHENTICATION */
302
303		case '4':
304			family = AF_INET;
305			break;
306
307#ifdef INET6
308		case '6':
309			family = AF_INET6;
310			break;
311#endif
312
313		default:
314			warnx("%c: unknown option", ch);
315			/* FALLTHROUGH */
316		case '?':
317			usage();
318			/* NOTREACHED */
319		}
320	}
321
322	argc -= optind;
323	argv += optind;
324
325	if (debug) {
326	    int s, ns, foo, error;
327	    const char *service = "telnet";
328	    struct addrinfo hints, *res;
329
330	    if (argc > 1) {
331		usage();
332		/* NOT REACHED */
333	    } else if (argc == 1)
334		service = *argv;
335
336	    memset(&hints, 0, sizeof(hints));
337	    hints.ai_flags = AI_PASSIVE;
338	    hints.ai_family = family;
339	    hints.ai_socktype = SOCK_STREAM;
340	    hints.ai_protocol = 0;
341	    error = getaddrinfo(NULL, service, &hints, &res);
342
343	    if (error) {
344		errx(1, "tcp/%s: %s\n", service, gai_strerror(error));
345		if (error == EAI_SYSTEM)
346		    errx(1, "tcp/%s: %s\n", service, strerror(errno));
347		usage();
348	    }
349
350	    s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
351	    if (s < 0)
352		    err(1, "socket");
353	    (void) setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
354				(char *)&on, sizeof(on));
355	    if (debug > 1)
356	        (void) setsockopt(s, SOL_SOCKET, SO_DEBUG,
357				(char *)&on, sizeof(on));
358	    if (bind(s, res->ai_addr, res->ai_addrlen) < 0)
359		err(1, "bind");
360	    if (listen(s, 1) < 0)
361		err(1, "listen");
362	    foo = res->ai_addrlen;
363	    ns = accept(s, res->ai_addr, &foo);
364	    if (ns < 0)
365		err(1, "accept");
366	    (void) setsockopt(ns, SOL_SOCKET, SO_DEBUG,
367				(char *)&on, sizeof(on));
368	    (void) dup2(ns, 0);
369	    (void) close(ns);
370	    (void) close(s);
371#ifdef convex
372	} else if (argc == 1) {
373		; /* VOID*/		/* Just ignore the host/port name */
374#endif
375	} else if (argc > 0) {
376		usage();
377		/* NOT REACHED */
378	}
379
380	openlog("telnetd", LOG_PID | LOG_ODELAY, LOG_DAEMON);
381	fromlen = sizeof (from);
382	if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) {
383		warn("getpeername");
384		_exit(1);
385	}
386	if (keepalive &&
387	    setsockopt(0, SOL_SOCKET, SO_KEEPALIVE,
388			(char *)&on, sizeof (on)) < 0) {
389		syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
390	}
391
392#if	defined(IPPROTO_IP) && defined(IP_TOS)
393	if (from.ss_family == AF_INET) {
394# if	defined(HAS_GETTOS)
395		struct tosent *tp;
396		if (tos < 0 && (tp = gettosbyname("telnet", "tcp")))
397			tos = tp->t_tos;
398# endif
399		if (tos < 0)
400			tos = 020;	/* Low Delay bit */
401		if (tos
402		   && (setsockopt(0, IPPROTO_IP, IP_TOS,
403				  (char *)&tos, sizeof(tos)) < 0)
404		   && (errno != ENOPROTOOPT) )
405			syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
406	}
407#endif	/* defined(IPPROTO_IP) && defined(IP_TOS) */
408	net = 0;
409	doit((struct sockaddr *)&from);
410	/* NOTREACHED */
411	return(0);
412}  /* end of main */
413
414	void
415usage()
416{
417	fprintf(stderr, "usage: telnetd");
418#ifdef	AUTHENTICATION
419	fprintf(stderr,
420	    " [-4] [-6] [-a (debug|other|user|valid|off|none)]\n\t");
421#endif
422#ifdef BFTPDAEMON
423	fprintf(stderr, " [-B]");
424#endif
425	fprintf(stderr, " [-debug]");
426#ifdef DIAGNOSTICS
427	fprintf(stderr, " [-D (options|report|exercise|netdata|ptydata)]\n\t");
428#endif
429#ifdef	AUTHENTICATION
430	fprintf(stderr, " [-edebug]");
431#endif
432	fprintf(stderr, " [-h]");
433#if	defined(LINEMODE) && defined(KLUDGELINEMODE)
434	fprintf(stderr, " [-k]");
435#endif
436#ifdef LINEMODE
437	fprintf(stderr, " [-l]");
438#endif
439	fprintf(stderr, " [-n]");
440	fprintf(stderr, "\n\t");
441#ifdef	HAS_GETTOS
442	fprintf(stderr, " [-S tos]");
443#endif
444#ifdef	AUTHENTICATION
445	fprintf(stderr, " [-X auth-type]");
446#endif
447	fprintf(stderr, " [-u utmp_hostname_length] [-U]");
448	fprintf(stderr, " [port]\n");
449	exit(1);
450}
451
452/*
453 * getterminaltype
454 *
455 *	Ask the other end to send along its terminal type and speed.
456 * Output is the variable terminaltype filled in.
457 */
458static unsigned char ttytype_sbbuf[] = {
459	IAC, SB, TELOPT_TTYPE, TELQUAL_SEND, IAC, SE
460};
461
462
463#ifndef	AUTHENTICATION
464#define undef2 __unused
465#else
466#define undef2
467#endif
468
469static int
470getterminaltype(char *name undef2)
471{
472    int retval = -1;
473
474    settimer(baseline);
475#ifdef	AUTHENTICATION
476    /*
477     * Handle the Authentication option before we do anything else.
478     */
479    if (auth_level >= 0) {
480	send_do(TELOPT_AUTHENTICATION, 1);
481	while (his_will_wont_is_changing(TELOPT_AUTHENTICATION))
482	    ttloop();
483	if (his_state_is_will(TELOPT_AUTHENTICATION)) {
484	    retval = auth_wait(name);
485	}
486    }
487#endif
488
489#ifdef	ENCRYPTION
490    send_will(TELOPT_ENCRYPT, 1);
491#endif	/* ENCRYPTION */
492    send_do(TELOPT_TTYPE, 1);
493    send_do(TELOPT_TSPEED, 1);
494    send_do(TELOPT_XDISPLOC, 1);
495    send_do(TELOPT_NEW_ENVIRON, 1);
496    send_do(TELOPT_OLD_ENVIRON, 1);
497    while (
498#ifdef	ENCRYPTION
499	   his_do_dont_is_changing(TELOPT_ENCRYPT) ||
500#endif	/* ENCRYPTION */
501	   his_will_wont_is_changing(TELOPT_TTYPE) ||
502	   his_will_wont_is_changing(TELOPT_TSPEED) ||
503	   his_will_wont_is_changing(TELOPT_XDISPLOC) ||
504	   his_will_wont_is_changing(TELOPT_NEW_ENVIRON) ||
505	   his_will_wont_is_changing(TELOPT_OLD_ENVIRON)) {
506	ttloop();
507    }
508#ifdef	ENCRYPTION
509    /*
510     * Wait for the negotiation of what type of encryption we can
511     * send with.  If autoencrypt is not set, this will just return.
512     */
513    if (his_state_is_will(TELOPT_ENCRYPT)) {
514	encrypt_wait();
515    }
516#endif	/* ENCRYPTION */
517    if (his_state_is_will(TELOPT_TSPEED)) {
518	static unsigned char sb[] =
519			{ IAC, SB, TELOPT_TSPEED, TELQUAL_SEND, IAC, SE };
520
521	output_datalen(sb, sizeof sb);
522	DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
523    }
524    if (his_state_is_will(TELOPT_XDISPLOC)) {
525	static unsigned char sb[] =
526			{ IAC, SB, TELOPT_XDISPLOC, TELQUAL_SEND, IAC, SE };
527
528	output_datalen(sb, sizeof sb);
529	DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
530    }
531    if (his_state_is_will(TELOPT_NEW_ENVIRON)) {
532	static unsigned char sb[] =
533			{ IAC, SB, TELOPT_NEW_ENVIRON, TELQUAL_SEND, IAC, SE };
534
535	output_datalen(sb, sizeof sb);
536	DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
537    }
538    else if (his_state_is_will(TELOPT_OLD_ENVIRON)) {
539	static unsigned char sb[] =
540			{ IAC, SB, TELOPT_OLD_ENVIRON, TELQUAL_SEND, IAC, SE };
541
542	output_datalen(sb, sizeof sb);
543	DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
544    }
545    if (his_state_is_will(TELOPT_TTYPE)) {
546
547	output_datalen(ttytype_sbbuf, sizeof ttytype_sbbuf);
548	DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2,
549					sizeof ttytype_sbbuf - 2););
550    }
551    if (his_state_is_will(TELOPT_TSPEED)) {
552	while (sequenceIs(tspeedsubopt, baseline))
553	    ttloop();
554    }
555    if (his_state_is_will(TELOPT_XDISPLOC)) {
556	while (sequenceIs(xdisplocsubopt, baseline))
557	    ttloop();
558    }
559    if (his_state_is_will(TELOPT_NEW_ENVIRON)) {
560	while (sequenceIs(environsubopt, baseline))
561	    ttloop();
562    }
563    if (his_state_is_will(TELOPT_OLD_ENVIRON)) {
564	while (sequenceIs(oenvironsubopt, baseline))
565	    ttloop();
566    }
567    if (his_state_is_will(TELOPT_TTYPE)) {
568	char first[256], last[256];
569
570	while (sequenceIs(ttypesubopt, baseline))
571	    ttloop();
572
573	/*
574	 * If the other side has already disabled the option, then
575	 * we have to just go with what we (might) have already gotten.
576	 */
577	if (his_state_is_will(TELOPT_TTYPE) && !terminaltypeok(terminaltype)) {
578	    (void) strncpy(first, terminaltype, sizeof(first)-1);
579	    first[sizeof(first)-1] = '\0';
580	    for(;;) {
581		/*
582		 * Save the unknown name, and request the next name.
583		 */
584		(void) strncpy(last, terminaltype, sizeof(last)-1);
585		last[sizeof(last)-1] = '\0';
586		_gettermname();
587		if (terminaltypeok(terminaltype))
588		    break;
589		if ((strncmp(last, terminaltype, sizeof(last)) == 0) ||
590		    his_state_is_wont(TELOPT_TTYPE)) {
591		    /*
592		     * We've hit the end.  If this is the same as
593		     * the first name, just go with it.
594		     */
595		    if (strncmp(first, terminaltype, sizeof(first)) == 0)
596			break;
597		    /*
598		     * Get the terminal name one more time, so that
599		     * RFC1091 compliant telnets will cycle back to
600		     * the start of the list.
601		     */
602		     _gettermname();
603		    if (strncmp(first, terminaltype, sizeof(first)) != 0) {
604			(void) strncpy(terminaltype, first, sizeof(terminaltype)-1);
605			terminaltype[sizeof(terminaltype)-1] = '\0';
606		    }
607		    break;
608		}
609	    }
610	}
611    }
612    return(retval);
613}  /* end of getterminaltype */
614
615static void
616_gettermname(void)
617{
618    /*
619     * If the client turned off the option,
620     * we can't send another request, so we
621     * just return.
622     */
623    if (his_state_is_wont(TELOPT_TTYPE))
624	return;
625    settimer(baseline);
626    output_datalen(ttytype_sbbuf, sizeof ttytype_sbbuf);
627    DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2,
628					sizeof ttytype_sbbuf - 2););
629    while (sequenceIs(ttypesubopt, baseline))
630	ttloop();
631}
632
633int
634terminaltypeok(char *s)
635{
636    char buf[1024];
637
638    if (terminaltype == NULL)
639	return(1);
640
641    /*
642     * tgetent() will return 1 if the type is known, and
643     * 0 if it is not known.  If it returns -1, it couldn't
644     * open the database.  But if we can't open the database,
645     * it won't help to say we failed, because we won't be
646     * able to verify anything else.  So, we treat -1 like 1.
647     */
648    if (tgetent(buf, s) == 0)
649	return(0);
650    return(1);
651}
652
653/*
654 * Get a pty, scan input lines.
655 */
656void
657doit(struct sockaddr *who)
658{
659	int err_; /* XXX */
660	int ptynum;
661
662	/*
663	 * Find an available pty to use.
664	 */
665#ifndef	convex
666	pty = getpty(&ptynum);
667	if (pty < 0)
668		fatal(net, "All network ports in use");
669#else
670	for (;;) {
671		char *lp;
672
673		if ((lp = getpty()) == NULL)
674			fatal(net, "Out of ptys");
675
676		if ((pty = open(lp, 2)) >= 0) {
677			strlcpy(line,lp,sizeof(line));
678			line[5] = 't';
679			break;
680		}
681	}
682#endif
683
684	/* get name of connected client */
685	if (realhostname_sa(remote_hostname, sizeof(remote_hostname) - 1,
686	    who, who->sa_len) == HOSTNAME_INVALIDADDR && registerd_host_only)
687		fatal(net, "Couldn't resolve your address into a host name.\r\n\
688	Please contact your net administrator");
689	remote_hostname[sizeof(remote_hostname) - 1] = '\0';
690
691	if (!isdigit(remote_hostname[0]) && strlen(remote_hostname) > utmp_len)
692		err_ = getnameinfo(who, who->sa_len, remote_hostname,
693				  sizeof(remote_hostname), NULL, 0,
694				  NI_NUMERICHOST);
695		/* XXX: do 'err_' check */
696
697	(void) gethostname(host_name, sizeof(host_name) - 1);
698	host_name[sizeof(host_name) - 1] = '\0';
699	hostname = host_name;
700
701#ifdef	AUTHENTICATION
702#ifdef	ENCRYPTION
703/* The above #ifdefs should actually be "or"'ed, not "and"'ed.
704 * This is a byproduct of needing "#ifdef" and not "#if defined()"
705 * for unifdef. XXX MarkM
706 */
707	auth_encrypt_init(hostname, remote_hostname, "TELNETD", 1);
708#endif
709#endif
710
711	init_env();
712	/*
713	 * get terminal type.
714	 */
715	*user_name = 0;
716	level = getterminaltype(user_name);
717	setenv("TERM", terminaltype ? terminaltype : "network", 1);
718
719	telnet(net, pty, remote_hostname);	/* begin server process */
720
721	/*NOTREACHED*/
722}  /* end of doit */
723
724/*
725 * Main loop.  Select from pty and network, and
726 * hand data to telnet receiver finite state machine.
727 */
728void
729telnet(int f, int p, char *host)
730{
731	int on = 1;
732#define	TABBUFSIZ	512
733	char	defent[TABBUFSIZ];
734	char	defstrs[TABBUFSIZ];
735#undef	TABBUFSIZ
736	char *HE;
737	char *HN;
738	char *IM;
739	char *IF;
740	char *if_buf;
741	int if_fd = -1;
742	struct stat statbuf;
743	int nfd;
744
745	/*
746	 * Initialize the slc mapping table.
747	 */
748	get_slc_defaults();
749
750	/*
751	 * Do some tests where it is desireable to wait for a response.
752	 * Rather than doing them slowly, one at a time, do them all
753	 * at once.
754	 */
755	if (my_state_is_wont(TELOPT_SGA))
756		send_will(TELOPT_SGA, 1);
757	/*
758	 * Is the client side a 4.2 (NOT 4.3) system?  We need to know this
759	 * because 4.2 clients are unable to deal with TCP urgent data.
760	 *
761	 * To find out, we send out a "DO ECHO".  If the remote system
762	 * answers "WILL ECHO" it is probably a 4.2 client, and we note
763	 * that fact ("WILL ECHO" ==> that the client will echo what
764	 * WE, the server, sends it; it does NOT mean that the client will
765	 * echo the terminal input).
766	 */
767	send_do(TELOPT_ECHO, 1);
768
769#ifdef	LINEMODE
770	if (his_state_is_wont(TELOPT_LINEMODE)) {
771		/* Query the peer for linemode support by trying to negotiate
772		 * the linemode option.
773		 */
774		linemode = 0;
775		editmode = 0;
776		send_do(TELOPT_LINEMODE, 1);  /* send do linemode */
777	}
778#endif	/* LINEMODE */
779
780	/*
781	 * Send along a couple of other options that we wish to negotiate.
782	 */
783	send_do(TELOPT_NAWS, 1);
784	send_will(TELOPT_STATUS, 1);
785	flowmode = 1;		/* default flow control state */
786	restartany = -1;	/* uninitialized... */
787	send_do(TELOPT_LFLOW, 1);
788
789	/*
790	 * Spin, waiting for a response from the DO ECHO.  However,
791	 * some REALLY DUMB telnets out there might not respond
792	 * to the DO ECHO.  So, we spin looking for NAWS, (most dumb
793	 * telnets so far seem to respond with WONT for a DO that
794	 * they don't understand...) because by the time we get the
795	 * response, it will already have processed the DO ECHO.
796	 * Kludge upon kludge.
797	 */
798	while (his_will_wont_is_changing(TELOPT_NAWS))
799		ttloop();
800
801	/*
802	 * But...
803	 * The client might have sent a WILL NAWS as part of its
804	 * startup code; if so, we'll be here before we get the
805	 * response to the DO ECHO.  We'll make the assumption
806	 * that any implementation that understands about NAWS
807	 * is a modern enough implementation that it will respond
808	 * to our DO ECHO request; hence we'll do another spin
809	 * waiting for the ECHO option to settle down, which is
810	 * what we wanted to do in the first place...
811	 */
812	if (his_want_state_is_will(TELOPT_ECHO) &&
813	    his_state_is_will(TELOPT_NAWS)) {
814		while (his_will_wont_is_changing(TELOPT_ECHO))
815			ttloop();
816	}
817	/*
818	 * On the off chance that the telnet client is broken and does not
819	 * respond to the DO ECHO we sent, (after all, we did send the
820	 * DO NAWS negotiation after the DO ECHO, and we won't get here
821	 * until a response to the DO NAWS comes back) simulate the
822	 * receipt of a will echo.  This will also send a WONT ECHO
823	 * to the client, since we assume that the client failed to
824	 * respond because it believes that it is already in DO ECHO
825	 * mode, which we do not want.
826	 */
827	if (his_want_state_is_will(TELOPT_ECHO)) {
828		DIAG(TD_OPTIONS, output_data("td: simulating recv\r\n"));
829		willoption(TELOPT_ECHO);
830	}
831
832	/*
833	 * Finally, to clean things up, we turn on our echo.  This
834	 * will break stupid 4.2 telnets out of local terminal echo.
835	 */
836
837	if (my_state_is_wont(TELOPT_ECHO))
838		send_will(TELOPT_ECHO, 1);
839
840	/*
841	 * Turn on packet mode
842	 */
843	(void) ioctl(p, TIOCPKT, (char *)&on);
844
845#if	defined(LINEMODE) && defined(KLUDGELINEMODE)
846	/*
847	 * Continuing line mode support.  If client does not support
848	 * real linemode, attempt to negotiate kludge linemode by sending
849	 * the do timing mark sequence.
850	 */
851	if (lmodetype < REAL_LINEMODE)
852		send_do(TELOPT_TM, 1);
853#endif	/* defined(LINEMODE) && defined(KLUDGELINEMODE) */
854
855	/*
856	 * Call telrcv() once to pick up anything received during
857	 * terminal type negotiation, 4.2/4.3 determination, and
858	 * linemode negotiation.
859	 */
860	telrcv();
861
862	(void) ioctl(f, FIONBIO, (char *)&on);
863	(void) ioctl(p, FIONBIO, (char *)&on);
864
865#if	defined(SO_OOBINLINE)
866	(void) setsockopt(net, SOL_SOCKET, SO_OOBINLINE,
867				(char *)&on, sizeof on);
868#endif	/* defined(SO_OOBINLINE) */
869
870#ifdef	SIGTSTP
871	(void) signal(SIGTSTP, SIG_IGN);
872#endif
873#ifdef	SIGTTOU
874	/*
875	 * Ignoring SIGTTOU keeps the kernel from blocking us
876	 * in ttioct() in /sys/tty.c.
877	 */
878	(void) signal(SIGTTOU, SIG_IGN);
879#endif
880
881	(void) signal(SIGCHLD, cleanup);
882
883#ifdef  TIOCNOTTY
884	{
885		int t;
886		t = open(_PATH_TTY, O_RDWR);
887		if (t >= 0) {
888			(void) ioctl(t, TIOCNOTTY, (char *)0);
889			(void) close(t);
890		}
891	}
892#endif
893
894	/*
895	 * Show banner that getty never gave.
896	 *
897	 * We put the banner in the pty input buffer.  This way, it
898	 * gets carriage return null processing, etc., just like all
899	 * other pty --> client data.
900	 */
901
902	if (getent(defent, "default") == 1) {
903		char *cp=defstrs;
904
905		HE = Getstr("he", &cp);
906		HN = Getstr("hn", &cp);
907		IM = Getstr("im", &cp);
908		IF = Getstr("if", &cp);
909		if (HN && *HN)
910			(void) strlcpy(host_name, HN, sizeof(host_name));
911		if (IF) {
912		    if_fd = open(IF, O_RDONLY, 000);
913		    IM = 0;
914		}
915		if (IM == 0)
916			IM = strdup("");
917	} else {
918		IM = strdup(DEFAULT_IM);
919		HE = 0;
920	}
921	edithost(HE, host_name);
922	if (hostinfo && *IM)
923		putf(IM, ptyibuf2);
924	if (if_fd != -1) {
925		if (fstat(if_fd, &statbuf) != -1 && statbuf.st_size > 0) {
926			if_buf = (char *) mmap (0, statbuf.st_size,
927			    PROT_READ, 0, if_fd, 0);
928			if (if_buf != MAP_FAILED) {
929				putf(if_buf, ptyibuf2);
930				munmap(if_buf, statbuf.st_size);
931			}
932		}
933		close (if_fd);
934	}
935
936	if (pcc)
937		(void) strncat(ptyibuf2, ptyip, pcc+1);
938	ptyip = ptyibuf2;
939	pcc = strlen(ptyip);
940#ifdef	LINEMODE
941	/*
942	 * Last check to make sure all our states are correct.
943	 */
944	init_termbuf();
945	localstat();
946#endif	/* LINEMODE */
947
948	DIAG(TD_REPORT, output_data("td: Entering processing loop\r\n"));
949
950	/*
951	 * Startup the login process on the slave side of the terminal
952	 * now.  We delay this until here to insure option negotiation
953	 * is complete.
954	 */
955	startslave(host, level, user_name);
956
957	nfd = ((f > p) ? f : p) + 1;
958	for (;;) {
959		fd_set ibits, obits, xbits;
960		int c;
961
962		if (ncc < 0 && pcc < 0)
963			break;
964
965		FD_ZERO(&ibits);
966		FD_ZERO(&obits);
967		FD_ZERO(&xbits);
968		/*
969		 * Never look for input if there's still
970		 * stuff in the corresponding output buffer
971		 */
972		if (nfrontp - nbackp || pcc > 0) {
973			FD_SET(f, &obits);
974		} else {
975			FD_SET(p, &ibits);
976		}
977		if (pfrontp - pbackp || ncc > 0) {
978			FD_SET(p, &obits);
979		} else {
980			FD_SET(f, &ibits);
981		}
982		if (!SYNCHing) {
983			FD_SET(f, &xbits);
984		}
985		if ((c = select(nfd, &ibits, &obits, &xbits,
986						(struct timeval *)0)) < 1) {
987			if (c == -1) {
988				if (errno == EINTR) {
989					continue;
990				}
991			}
992			sleep(5);
993			continue;
994		}
995
996		/*
997		 * Any urgent data?
998		 */
999		if (FD_ISSET(net, &xbits)) {
1000		    SYNCHing = 1;
1001		}
1002
1003		/*
1004		 * Something to read from the network...
1005		 */
1006		if (FD_ISSET(net, &ibits)) {
1007#if	!defined(SO_OOBINLINE)
1008			/*
1009			 * In 4.2 (and 4.3 beta) systems, the
1010			 * OOB indication and data handling in the kernel
1011			 * is such that if two separate TCP Urgent requests
1012			 * come in, one byte of TCP data will be overlaid.
1013			 * This is fatal for Telnet, but we try to live
1014			 * with it.
1015			 *
1016			 * In addition, in 4.2 (and...), a special protocol
1017			 * is needed to pick up the TCP Urgent data in
1018			 * the correct sequence.
1019			 *
1020			 * What we do is:  if we think we are in urgent
1021			 * mode, we look to see if we are "at the mark".
1022			 * If we are, we do an OOB receive.  If we run
1023			 * this twice, we will do the OOB receive twice,
1024			 * but the second will fail, since the second
1025			 * time we were "at the mark", but there wasn't
1026			 * any data there (the kernel doesn't reset
1027			 * "at the mark" until we do a normal read).
1028			 * Once we've read the OOB data, we go ahead
1029			 * and do normal reads.
1030			 *
1031			 * There is also another problem, which is that
1032			 * since the OOB byte we read doesn't put us
1033			 * out of OOB state, and since that byte is most
1034			 * likely the TELNET DM (data mark), we would
1035			 * stay in the TELNET SYNCH (SYNCHing) state.
1036			 * So, clocks to the rescue.  If we've "just"
1037			 * received a DM, then we test for the
1038			 * presence of OOB data when the receive OOB
1039			 * fails (and AFTER we did the normal mode read
1040			 * to clear "at the mark").
1041			 */
1042		    if (SYNCHing) {
1043			int atmark;
1044
1045			(void) ioctl(net, SIOCATMARK, (char *)&atmark);
1046			if (atmark) {
1047			    ncc = recv(net, netibuf, sizeof (netibuf), MSG_OOB);
1048			    if ((ncc == -1) && (errno == EINVAL)) {
1049				ncc = read(net, netibuf, sizeof (netibuf));
1050				if (sequenceIs(didnetreceive, gotDM)) {
1051				    SYNCHing = stilloob(net);
1052				}
1053			    }
1054			} else {
1055			    ncc = read(net, netibuf, sizeof (netibuf));
1056			}
1057		    } else {
1058			ncc = read(net, netibuf, sizeof (netibuf));
1059		    }
1060		    settimer(didnetreceive);
1061#else	/* !defined(SO_OOBINLINE)) */
1062		    ncc = read(net, netibuf, sizeof (netibuf));
1063#endif	/* !defined(SO_OOBINLINE)) */
1064		    if (ncc < 0 && errno == EWOULDBLOCK)
1065			ncc = 0;
1066		    else {
1067			if (ncc <= 0) {
1068			    break;
1069			}
1070			netip = netibuf;
1071		    }
1072		    DIAG((TD_REPORT | TD_NETDATA),
1073			output_data("td: netread %d chars\r\n", ncc));
1074		    DIAG(TD_NETDATA, printdata("nd", netip, ncc));
1075		}
1076
1077		/*
1078		 * Something to read from the pty...
1079		 */
1080		if (FD_ISSET(p, &ibits)) {
1081			pcc = read(p, ptyibuf, BUFSIZ);
1082			/*
1083			 * On some systems, if we try to read something
1084			 * off the master side before the slave side is
1085			 * opened, we get EIO.
1086			 */
1087			if (pcc < 0 && (errno == EWOULDBLOCK ||
1088#ifdef	EAGAIN
1089					errno == EAGAIN ||
1090#endif
1091					errno == EIO)) {
1092				pcc = 0;
1093			} else {
1094				if (pcc <= 0)
1095					break;
1096#ifdef	LINEMODE
1097				/*
1098				 * If ioctl from pty, pass it through net
1099				 */
1100				if (ptyibuf[0] & TIOCPKT_IOCTL) {
1101					copy_termbuf(ptyibuf+1, pcc-1);
1102					localstat();
1103					pcc = 1;
1104				}
1105#endif	/* LINEMODE */
1106				if (ptyibuf[0] & TIOCPKT_FLUSHWRITE) {
1107					netclear();	/* clear buffer back */
1108#ifndef	NO_URGENT
1109					/*
1110					 * There are client telnets on some
1111					 * operating systems get screwed up
1112					 * royally if we send them urgent
1113					 * mode data.
1114					 */
1115					output_data("%c%c", IAC, DM);
1116					neturg = nfrontp-1; /* off by one XXX */
1117					DIAG(TD_OPTIONS,
1118					    printoption("td: send IAC", DM));
1119
1120#endif
1121				}
1122				if (his_state_is_will(TELOPT_LFLOW) &&
1123				    (ptyibuf[0] &
1124				     (TIOCPKT_NOSTOP|TIOCPKT_DOSTOP))) {
1125					int newflow =
1126					    ptyibuf[0] & TIOCPKT_DOSTOP ? 1 : 0;
1127					if (newflow != flowmode) {
1128						flowmode = newflow;
1129						output_data("%c%c%c%c%c%c",
1130							IAC, SB, TELOPT_LFLOW,
1131							flowmode ? LFLOW_ON
1132								 : LFLOW_OFF,
1133							IAC, SE);
1134						DIAG(TD_OPTIONS, printsub('>',
1135						    (unsigned char *)nfrontp-4,
1136						    4););
1137					}
1138				}
1139				pcc--;
1140				ptyip = ptyibuf+1;
1141			}
1142		}
1143
1144		while (pcc > 0) {
1145			if ((&netobuf[BUFSIZ] - nfrontp) < 2)
1146				break;
1147			c = *ptyip++ & 0377, pcc--;
1148			if (c == IAC)
1149				output_data("%c", c);
1150			output_data("%c", c);
1151			if ((c == '\r') && (my_state_is_wont(TELOPT_BINARY))) {
1152				if (pcc > 0 && ((*ptyip & 0377) == '\n')) {
1153					output_data("%c", *ptyip++ & 0377);
1154					pcc--;
1155				} else
1156					output_data("%c", '\0');
1157			}
1158		}
1159
1160		if (FD_ISSET(f, &obits) && (nfrontp - nbackp) > 0)
1161			netflush();
1162		if (ncc > 0)
1163			telrcv();
1164		if (FD_ISSET(p, &obits) && (pfrontp - pbackp) > 0)
1165			ptyflush();
1166	}
1167	cleanup(0);
1168}  /* end of telnet */
1169
1170#ifndef	TCSIG
1171# ifdef	TIOCSIG
1172#  define TCSIG TIOCSIG
1173# endif
1174#endif
1175
1176/*
1177 * Send interrupt to process on other side of pty.
1178 * If it is in raw mode, just write NULL;
1179 * otherwise, write intr char.
1180 */
1181void
1182interrupt(void)
1183{
1184	ptyflush();	/* half-hearted */
1185
1186#ifdef	TCSIG
1187	(void) ioctl(pty, TCSIG, SIGINT);
1188#else	/* TCSIG */
1189	init_termbuf();
1190	*pfrontp++ = slctab[SLC_IP].sptr ?
1191			(unsigned char)*slctab[SLC_IP].sptr : '\177';
1192#endif	/* TCSIG */
1193}
1194
1195/*
1196 * Send quit to process on other side of pty.
1197 * If it is in raw mode, just write NULL;
1198 * otherwise, write quit char.
1199 */
1200void
1201sendbrk(void)
1202{
1203	ptyflush();	/* half-hearted */
1204#ifdef	TCSIG
1205	(void) ioctl(pty, TCSIG, SIGQUIT);
1206#else	/* TCSIG */
1207	init_termbuf();
1208	*pfrontp++ = slctab[SLC_ABORT].sptr ?
1209			(unsigned char)*slctab[SLC_ABORT].sptr : '\034';
1210#endif	/* TCSIG */
1211}
1212
1213void
1214sendsusp(void)
1215{
1216#ifdef	SIGTSTP
1217	ptyflush();	/* half-hearted */
1218# ifdef	TCSIG
1219	(void) ioctl(pty, TCSIG, SIGTSTP);
1220# else	/* TCSIG */
1221	*pfrontp++ = slctab[SLC_SUSP].sptr ?
1222			(unsigned char)*slctab[SLC_SUSP].sptr : '\032';
1223# endif	/* TCSIG */
1224#endif	/* SIGTSTP */
1225}
1226
1227/*
1228 * When we get an AYT, if ^T is enabled, use that.  Otherwise,
1229 * just send back "[Yes]".
1230 */
1231void
1232recv_ayt(void)
1233{
1234#if	defined(SIGINFO) && defined(TCSIG)
1235	if (slctab[SLC_AYT].sptr && *slctab[SLC_AYT].sptr != _POSIX_VDISABLE) {
1236		(void) ioctl(pty, TCSIG, SIGINFO);
1237		return;
1238	}
1239#endif
1240	output_data("\r\n[Yes]\r\n");
1241}
1242
1243void
1244doeof(void)
1245{
1246	init_termbuf();
1247
1248#if	defined(LINEMODE) && defined(USE_TERMIO) && (VEOF == VMIN)
1249	if (!tty_isediting()) {
1250		extern char oldeofc;
1251		*pfrontp++ = oldeofc;
1252		return;
1253	}
1254#endif
1255	*pfrontp++ = slctab[SLC_EOF].sptr ?
1256			(unsigned char)*slctab[SLC_EOF].sptr : '\004';
1257}
1258