1/*-
2 * Copyright (c) 1983, 1988, 1989, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 * Copyright (c) 2002 Networks Associates Technology, Inc.
5 * All rights reserved.
6 *
7 * Portions of this software were developed for the FreeBSD Project by
8 * ThinkSec AS and NAI Labs, the Security Research Division of Network
9 * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
10 * ("CBOSS"), as part of the DARPA CHATS research program.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 *    notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 *    notice, this list of conditions and the following disclaimer in the
19 *    documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#if 0
38#ifndef lint
39static const char copyright[] =
40"@(#) Copyright (c) 1983, 1988, 1989, 1993\n\
41	The Regents of the University of California.  All rights reserved.\n";
42#endif /* not lint */
43
44#ifndef lint
45static const char sccsid[] = "@(#)rlogind.c	8.1 (Berkeley) 6/4/93";
46#endif /* not lint */
47#endif
48#include <sys/cdefs.h>
49__FBSDID("$FreeBSD$");
50
51/*
52 * remote login server:
53 *	\0
54 *	remuser\0
55 *	locuser\0
56 *	terminal_type/speed\0
57 *	data
58 */
59
60#define	FD_SETSIZE	16		/* don't need many bits for select */
61#include <sys/types.h>
62#include <sys/param.h>
63#include <sys/stat.h>
64#include <sys/ioctl.h>
65#include <signal.h>
66#include <termios.h>
67
68#include <sys/socket.h>
69#include <netinet/in.h>
70#include <netinet/in_systm.h>
71#include <netinet/ip.h>
72#include <netinet/tcp.h>
73#include <arpa/inet.h>
74#include <netdb.h>
75
76#include <errno.h>
77#include <libutil.h>
78#include <paths.h>
79#include <poll.h>
80#include <pwd.h>
81#include <syslog.h>
82#include <stdio.h>
83#include <stdlib.h>
84#include <string.h>
85#include <unistd.h>
86#ifdef USE_BLACKLIST
87#include <blacklist.h>
88#endif
89
90#ifndef TIOCPKT_WINDOW
91#define TIOCPKT_WINDOW 0x80
92#endif
93
94#define		ARGSTR			"Daln"
95
96char	*env[2];
97#define	NMAX 30
98char	lusername[NMAX+1], rusername[NMAX+1];
99static	char term[64] = "TERM=";
100#define	ENVSIZE	(sizeof("TERM=")-1)	/* skip null for concatenation */
101int	keepalive = 1;
102int	check_all = 0;
103int	no_delay;
104
105struct	passwd *pwd;
106
107union sockunion {
108	struct sockinet {
109		u_char si_len;
110		u_char si_family;
111		u_short si_port;
112	} su_si;
113	struct sockaddr_in  su_sin;
114	struct sockaddr_in6 su_sin6;
115};
116#define su_len		su_si.si_len
117#define su_family	su_si.si_family
118#define su_port		su_si.si_port
119
120void	doit(int, union sockunion *);
121int	control(int, char *, int);
122void	protocol(int, int);
123void	cleanup(int);
124void	fatal(int, char *, int);
125int	do_rlogin(union sockunion *);
126void	getstr(char *, int, char *);
127void	setup_term(int);
128int	do_krb_login(struct sockaddr_in *);
129void	usage(void);
130
131
132int
133main(int argc, char *argv[])
134{
135	extern int __check_rhosts_file;
136	union sockunion from;
137	socklen_t fromlen;
138	int ch, on;
139
140	openlog("rlogind", LOG_PID | LOG_CONS, LOG_AUTH);
141
142	opterr = 0;
143	while ((ch = getopt(argc, argv, ARGSTR)) != -1)
144		switch (ch) {
145		case 'D':
146			no_delay = 1;
147			break;
148		case 'a':
149			check_all = 1;
150			break;
151		case 'l':
152			__check_rhosts_file = 0;
153			break;
154		case 'n':
155			keepalive = 0;
156			break;
157		case '?':
158		default:
159			usage();
160			break;
161		}
162	argc -= optind;
163	argv += optind;
164
165	fromlen = sizeof (from);
166	if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) {
167		syslog(LOG_ERR,"Can't get peer name of remote host: %m");
168		fatal(STDERR_FILENO, "Can't get peer name of remote host", 1);
169	}
170	on = 1;
171	if (keepalive &&
172	    setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof (on)) < 0)
173		syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
174	if (no_delay &&
175	    setsockopt(0, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on)) < 0)
176		syslog(LOG_WARNING, "setsockopt (TCP_NODELAY): %m");
177	if (from.su_family == AF_INET)
178      {
179	on = IPTOS_LOWDELAY;
180	if (setsockopt(0, IPPROTO_IP, IP_TOS, (char *)&on, sizeof(int)) < 0)
181		syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
182      }
183
184	doit(0, &from);
185	return 0;
186}
187
188int	child;
189int	netf;
190char	line[MAXPATHLEN];
191int	confirmed;
192
193struct winsize win = { 0, 0, 0, 0 };
194
195
196void
197doit(int f, union sockunion *fromp)
198{
199	int master, pid, on = 1;
200	int authenticated = 0;
201	char hostname[2 * MAXHOSTNAMELEN + 1];
202	char nameinfo[2 * INET6_ADDRSTRLEN + 1];
203	char c;
204
205	alarm(60);
206	read(f, &c, 1);
207
208	if (c != 0)
209		exit(1);
210
211	alarm(0);
212
213	realhostname_sa(hostname, sizeof(hostname) - 1,
214			    (struct sockaddr *)fromp, fromp->su_len);
215	/* error check ? */
216	fromp->su_port = ntohs((u_short)fromp->su_port);
217	hostname[sizeof(hostname) - 1] = '\0';
218
219	{
220		if ((fromp->su_family != AF_INET
221#ifdef INET6
222		  && fromp->su_family != AF_INET6
223#endif
224		     ) ||
225		    fromp->su_port >= IPPORT_RESERVED ||
226		    fromp->su_port < IPPORT_RESERVED/2) {
227			getnameinfo((struct sockaddr *)fromp,
228				    fromp->su_len,
229				    nameinfo, sizeof(nameinfo), NULL, 0,
230				    NI_NUMERICHOST);
231			/* error check ? */
232			syslog(LOG_NOTICE, "Connection from %s on illegal port",
233			       nameinfo);
234#ifdef USE_BLACKLIST
235			blacklist(1, STDIN_FILENO, "illegal port");
236#endif
237			fatal(f, "Permission denied", 0);
238		}
239#ifdef IP_OPTIONS
240		if (fromp->su_family == AF_INET)
241	      {
242		u_char optbuf[BUFSIZ/3];
243		socklen_t optsize = sizeof(optbuf);
244		int ipproto, i;
245		struct protoent *ip;
246
247		if ((ip = getprotobyname("ip")) != NULL)
248			ipproto = ip->p_proto;
249		else
250			ipproto = IPPROTO_IP;
251		if (getsockopt(0, ipproto, IP_OPTIONS, (char *)optbuf,
252		    &optsize) == 0 && optsize != 0) {
253			for (i = 0; i < optsize; ) {
254				u_char c = optbuf[i];
255				if (c == IPOPT_LSRR || c == IPOPT_SSRR) {
256					syslog(LOG_NOTICE,
257						"Connection refused from %s with IP option %s",
258						inet_ntoa(fromp->su_sin.sin_addr),
259						c == IPOPT_LSRR ? "LSRR" : "SSRR");
260#ifdef USE_BLACKLIST
261					blacklist(1, STDIN_FILENO, "source routing present");
262#endif
263					exit(1);
264				}
265				if (c == IPOPT_EOL)
266					break;
267				i += (c == IPOPT_NOP) ? 1 : optbuf[i+1];
268			}
269		}
270	      }
271#endif
272		if (do_rlogin(fromp) == 0)
273			authenticated++;
274	}
275	if (confirmed == 0) {
276		write(f, "", 1);
277		confirmed = 1;		/* we sent the null! */
278	}
279	netf = f;
280
281	pid = forkpty(&master, line, NULL, &win);
282	if (pid < 0) {
283		if (errno == ENOENT)
284			fatal(f, "Out of ptys", 0);
285		else
286			fatal(f, "Forkpty", 1);
287	}
288	if (pid == 0) {
289		if (f > 2)	/* f should always be 0, but... */
290			(void) close(f);
291		setup_term(0);
292		if (*lusername=='-') {
293			syslog(LOG_ERR, "tried to pass user \"%s\" to login",
294			       lusername);
295#ifdef USE_BLACKLIST
296			blacklist(1, STDIN_FILENO, "invalid user");
297#endif
298			fatal(STDERR_FILENO, "invalid user", 0);
299		}
300#ifdef USE_BLACKLIST
301		blacklist(0, STDIN_FILENO, "success");
302#endif
303		if (authenticated) {
304			execl(_PATH_LOGIN, "login", "-p",
305			    "-h", hostname, "-f", lusername, (char *)NULL);
306		} else
307			execl(_PATH_LOGIN, "login", "-p",
308			    "-h", hostname, lusername, (char *)NULL);
309		fatal(STDERR_FILENO, _PATH_LOGIN, 1);
310		/*NOTREACHED*/
311	}
312	ioctl(f, FIONBIO, &on);
313	ioctl(master, FIONBIO, &on);
314	ioctl(master, TIOCPKT, &on);
315	signal(SIGCHLD, cleanup);
316	protocol(f, master);
317	signal(SIGCHLD, SIG_IGN);
318	cleanup(0);
319}
320
321char	magic[2] = { 0377, 0377 };
322char	oobdata[] = {TIOCPKT_WINDOW};
323
324/*
325 * Handle a "control" request (signaled by magic being present)
326 * in the data stream.  For now, we are only willing to handle
327 * window size changes.
328 */
329int
330control(int pty, char *cp, int n)
331{
332	struct winsize w;
333
334	if (n < 4 + (int)sizeof(w) || cp[2] != 's' || cp[3] != 's')
335		return (0);
336	oobdata[0] &= ~TIOCPKT_WINDOW;	/* we know he heard */
337	bcopy(cp+4, (char *)&w, sizeof(w));
338	w.ws_row = ntohs(w.ws_row);
339	w.ws_col = ntohs(w.ws_col);
340	w.ws_xpixel = ntohs(w.ws_xpixel);
341	w.ws_ypixel = ntohs(w.ws_ypixel);
342	(void)ioctl(pty, TIOCSWINSZ, &w);
343	return (4+sizeof (w));
344}
345
346/*
347 * rlogin "protocol" machine.
348 */
349void
350protocol(int f, int p)
351{
352	char pibuf[1024+1], fibuf[1024], *pbp = NULL, *fbp = NULL;
353	int pcc = 0, fcc = 0;
354	int cc, nfd, n;
355	char cntl;
356
357	/*
358	 * Must ignore SIGTTOU, otherwise we'll stop
359	 * when we try and set slave pty's window shape
360	 * (our controlling tty is the master pty).
361	 */
362	(void) signal(SIGTTOU, SIG_IGN);
363	send(f, oobdata, 1, MSG_OOB);	/* indicate new rlogin */
364	if (f > p)
365		nfd = f + 1;
366	else
367		nfd = p + 1;
368	for (;;) {
369		struct pollfd set[2];
370
371		set[0].fd = p;
372		set[0].events = POLLPRI;
373		set[1].fd = f;
374		set[1].events = 0;
375		if (fcc)
376			set[0].events |= POLLOUT;
377		else
378			set[1].events |= POLLIN;
379		if (pcc >= 0) {
380			if (pcc)
381				set[1].events |= POLLOUT;
382			else
383				set[0].events |= POLLIN;
384		}
385		if ((n = poll(set, 2, INFTIM)) < 0) {
386			if (errno == EINTR)
387				continue;
388			fatal(f, "poll", 1);
389		}
390		if (n == 0) {
391			/* shouldn't happen... */
392			sleep(5);
393			continue;
394		}
395#define	pkcontrol(c)	((c)&(TIOCPKT_FLUSHWRITE|TIOCPKT_NOSTOP|TIOCPKT_DOSTOP))
396		if (set[0].revents & POLLPRI) {
397			cc = read(p, &cntl, 1);
398			if (cc == 1 && pkcontrol(cntl)) {
399				cntl |= oobdata[0];
400				send(f, &cntl, 1, MSG_OOB);
401				if (cntl & TIOCPKT_FLUSHWRITE)
402					pcc = 0;
403			}
404		}
405		if (set[1].revents & POLLIN) {
406			fcc = read(f, fibuf, sizeof(fibuf));
407			if (fcc < 0 && errno == EWOULDBLOCK)
408				fcc = 0;
409			else {
410				char *cp;
411				int left, n;
412
413				if (fcc <= 0)
414					break;
415				fbp = fibuf;
416
417			top:
418				for (cp = fibuf; cp < fibuf+fcc-1; cp++)
419					if (cp[0] == magic[0] &&
420					    cp[1] == magic[1]) {
421						left = fcc - (cp-fibuf);
422						n = control(p, cp, left);
423						if (n) {
424							left -= n;
425							if (left > 0)
426								bcopy(cp+n, cp, left);
427							fcc -= n;
428							goto top; /* n^2 */
429						}
430					}
431			}
432		}
433
434		if (set[0].revents & POLLOUT && fcc > 0) {
435			cc = write(p, fbp, fcc);
436			if (cc > 0) {
437				fcc -= cc;
438				fbp += cc;
439			}
440		}
441
442		if (set[0].revents & POLLIN) {
443			pcc = read(p, pibuf, sizeof (pibuf));
444			pbp = pibuf;
445			if (pcc < 0 && errno == EWOULDBLOCK)
446				pcc = 0;
447			else if (pcc <= 0)
448				break;
449			else if (pibuf[0] == 0) {
450				pbp++, pcc--;
451			} else {
452				if (pkcontrol(pibuf[0])) {
453					pibuf[0] |= oobdata[0];
454					send(f, &pibuf[0], 1, MSG_OOB);
455				}
456				pcc = 0;
457			}
458		}
459		if (set[1].revents & POLLOUT && pcc > 0) {
460			cc = write(f, pbp, pcc);
461			if (cc > 0) {
462				pcc -= cc;
463				pbp += cc;
464			}
465		}
466	}
467}
468
469void
470cleanup(int signo __unused)
471{
472
473	shutdown(netf, SHUT_RDWR);
474	exit(1);
475}
476
477void
478fatal(int f, char *msg, int syserr)
479{
480	int len;
481	char buf[BUFSIZ], *bp = buf;
482
483	/*
484	 * Prepend binary one to message if we haven't sent
485	 * the magic null as confirmation.
486	 */
487	if (!confirmed)
488		*bp++ = '\01';		/* error indicator */
489	if (syserr)
490		len = snprintf(bp, sizeof(buf), "rlogind: %s: %s.\r\n",
491		    msg, strerror(errno));
492	else
493		len = snprintf(bp, sizeof(buf), "rlogind: %s.\r\n", msg);
494	if (len < 0)
495		len = 0;
496	(void) write(f, buf, bp + len - buf);
497	exit(1);
498}
499
500int
501do_rlogin(union sockunion *dest)
502{
503
504	getstr(rusername, sizeof(rusername), "remuser too long");
505	getstr(lusername, sizeof(lusername), "locuser too long");
506	getstr(term+ENVSIZE, sizeof(term)-ENVSIZE, "Terminal type too long");
507
508	pwd = getpwnam(lusername);
509	if (pwd == NULL)
510		return (-1);
511	/* XXX why don't we syslog() failure? */
512
513	return (iruserok_sa(dest, dest->su_len, pwd->pw_uid == 0, rusername,
514			    lusername));
515}
516
517void
518getstr(char *buf, int cnt, char *errmsg)
519{
520	char c;
521
522	do {
523		if (read(STDIN_FILENO, &c, 1) != 1)
524			exit(1);
525		if (--cnt < 0) {
526#ifdef USE_BLACKLIST
527			blacklist(1, STDIN_FILENO, "buffer overflow");
528#endif
529			fatal(STDOUT_FILENO, errmsg, 0);
530		}
531		*buf++ = c;
532	} while (c != 0);
533}
534
535extern	char **environ;
536
537void
538setup_term(int fd)
539{
540	char *cp;
541	char *speed;
542	struct termios tt, def;
543
544	cp = strchr(term + ENVSIZE, '/');
545#ifndef notyet
546	tcgetattr(fd, &tt);
547	if (cp) {
548		*cp++ = '\0';
549		speed = cp;
550		cp = strchr(speed, '/');
551		if (cp)
552			*cp++ = '\0';
553		cfsetspeed(&tt, atoi(speed));
554	}
555
556	cfmakesane(&def);
557	tt.c_iflag = def.c_iflag;
558	tt.c_oflag = def.c_oflag;
559	tt.c_lflag = def.c_lflag;
560	tcsetattr(fd, TCSAFLUSH, &tt);
561#else
562	if (cp) {
563		*cp++ = '\0';
564		speed = cp;
565		cp = strchr(speed, '/');
566		if (cp)
567			*cp++ = '\0';
568		tcgetattr(fd, &tt);
569		cfsetspeed(&tt, atoi(speed));
570		tcsetattr(fd, TCSAFLUSH, &tt);
571	}
572#endif
573
574	env[0] = term;
575	env[1] = 0;
576	environ = env;
577}
578
579void
580usage(void)
581{
582	syslog(LOG_ERR, "usage: rlogind [-" ARGSTR "]");
583}
584