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. All advertising materials mentioning features or use of this software
21 *    must display the following acknowledgement:
22 *	This product includes software developed by the University of
23 *	California, Berkeley and its contributors.
24 * 4. Neither the name of the University nor the names of its contributors
25 *    may be used to endorse or promote products derived from this software
26 *    without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * SUCH DAMAGE.
39 */
40
41#if 0
42#ifndef lint
43static const char copyright[] =
44"@(#) Copyright (c) 1983, 1988, 1989, 1993\n\
45	The Regents of the University of California.  All rights reserved.\n";
46#endif /* not lint */
47
48#ifndef lint
49static const char sccsid[] = "@(#)rlogind.c	8.1 (Berkeley) 6/4/93";
50#endif /* not lint */
51#endif
52#include <sys/cdefs.h>
53__FBSDID("$FreeBSD$");
54
55/*
56 * remote login server:
57 *	\0
58 *	remuser\0
59 *	locuser\0
60 *	terminal_type/speed\0
61 *	data
62 */
63
64#define	FD_SETSIZE	16		/* don't need many bits for select */
65#include <sys/types.h>
66#include <sys/param.h>
67#include <sys/stat.h>
68#include <sys/ioctl.h>
69#include <signal.h>
70#include <termios.h>
71
72#include <sys/socket.h>
73#include <netinet/in.h>
74#include <netinet/in_systm.h>
75#include <netinet/ip.h>
76#include <netinet/tcp.h>
77#include <arpa/inet.h>
78#include <netdb.h>
79
80#include <errno.h>
81#include <libutil.h>
82#include <paths.h>
83#include <pwd.h>
84#include <syslog.h>
85#include <stdio.h>
86#include <stdlib.h>
87#include <string.h>
88#include <unistd.h>
89
90
91#ifndef TIOCPKT_WINDOW
92#define TIOCPKT_WINDOW 0x80
93#endif
94
95#define		ARGSTR			"Daln"
96
97char	*env[2];
98#define	NMAX 30
99char	lusername[NMAX+1], rusername[NMAX+1];
100static	char term[64] = "TERM=";
101#define	ENVSIZE	(sizeof("TERM=")-1)	/* skip null for concatenation */
102int	keepalive = 1;
103int	check_all = 0;
104int	no_delay;
105
106struct	passwd *pwd;
107
108union sockunion {
109	struct sockinet {
110		u_char si_len;
111		u_char si_family;
112		u_short si_port;
113	} su_si;
114	struct sockaddr_in  su_sin;
115	struct sockaddr_in6 su_sin6;
116};
117#define su_len		su_si.si_len
118#define su_family	su_si.si_family
119#define su_port		su_si.si_port
120
121void	doit(int, union sockunion *);
122int	control(int, char *, int);
123void	protocol(int, int);
124void	cleanup(int);
125void	fatal(int, char *, int);
126int	do_rlogin(union sockunion *);
127void	getstr(char *, int, char *);
128void	setup_term(int);
129int	do_krb_login(struct sockaddr_in *);
130void	usage(void);
131
132
133int
134main(int argc, char *argv[])
135{
136	extern int __check_rhosts_file;
137	union sockunion from;
138	socklen_t fromlen;
139	int ch, on;
140
141	openlog("rlogind", LOG_PID | LOG_CONS, LOG_AUTH);
142
143	opterr = 0;
144	while ((ch = getopt(argc, argv, ARGSTR)) != -1)
145		switch (ch) {
146		case 'D':
147			no_delay = 1;
148			break;
149		case 'a':
150			check_all = 1;
151			break;
152		case 'l':
153			__check_rhosts_file = 0;
154			break;
155		case 'n':
156			keepalive = 0;
157			break;
158		case '?':
159		default:
160			usage();
161			break;
162		}
163	argc -= optind;
164	argv += optind;
165
166	fromlen = sizeof (from);
167	if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) {
168		syslog(LOG_ERR,"Can't get peer name of remote host: %m");
169		fatal(STDERR_FILENO, "Can't get peer name of remote host", 1);
170	}
171	on = 1;
172	if (keepalive &&
173	    setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof (on)) < 0)
174		syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
175	if (no_delay &&
176	    setsockopt(0, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on)) < 0)
177		syslog(LOG_WARNING, "setsockopt (TCP_NODELAY): %m");
178	if (from.su_family == AF_INET)
179      {
180	on = IPTOS_LOWDELAY;
181	if (setsockopt(0, IPPROTO_IP, IP_TOS, (char *)&on, sizeof(int)) < 0)
182		syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
183      }
184
185	doit(0, &from);
186	return 0;
187}
188
189int	child;
190int	netf;
191char	line[MAXPATHLEN];
192int	confirmed;
193
194struct winsize win = { 0, 0, 0, 0 };
195
196
197void
198doit(int f, union sockunion *fromp)
199{
200	int master, pid, on = 1;
201	int authenticated = 0;
202	char hostname[2 * MAXHOSTNAMELEN + 1];
203	char nameinfo[2 * INET6_ADDRSTRLEN + 1];
204	char c;
205
206	alarm(60);
207	read(f, &c, 1);
208
209	if (c != 0)
210		exit(1);
211
212	alarm(0);
213
214	realhostname_sa(hostname, sizeof(hostname) - 1,
215			    (struct sockaddr *)fromp, fromp->su_len);
216	/* error check ? */
217	fromp->su_port = ntohs((u_short)fromp->su_port);
218	hostname[sizeof(hostname) - 1] = '\0';
219
220	{
221		if ((fromp->su_family != AF_INET
222#ifdef INET6
223		  && fromp->su_family != AF_INET6
224#endif
225		     ) ||
226		    fromp->su_port >= IPPORT_RESERVED ||
227		    fromp->su_port < IPPORT_RESERVED/2) {
228			getnameinfo((struct sockaddr *)fromp,
229				    fromp->su_len,
230				    nameinfo, sizeof(nameinfo), NULL, 0,
231				    NI_NUMERICHOST);
232			/* error check ? */
233			syslog(LOG_NOTICE, "Connection from %s on illegal port",
234			       nameinfo);
235			fatal(f, "Permission denied", 0);
236		}
237#ifdef IP_OPTIONS
238		if (fromp->su_family == AF_INET)
239	      {
240		u_char optbuf[BUFSIZ/3];
241		socklen_t optsize = sizeof(optbuf);
242		int ipproto, i;
243		struct protoent *ip;
244
245		if ((ip = getprotobyname("ip")) != NULL)
246			ipproto = ip->p_proto;
247		else
248			ipproto = IPPROTO_IP;
249		if (getsockopt(0, ipproto, IP_OPTIONS, (char *)optbuf,
250		    &optsize) == 0 && optsize != 0) {
251			for (i = 0; i < optsize; ) {
252				u_char c = optbuf[i];
253				if (c == IPOPT_LSRR || c == IPOPT_SSRR) {
254					syslog(LOG_NOTICE,
255						"Connection refused from %s with IP option %s",
256						inet_ntoa(fromp->su_sin.sin_addr),
257						c == IPOPT_LSRR ? "LSRR" : "SSRR");
258					exit(1);
259				}
260				if (c == IPOPT_EOL)
261					break;
262				i += (c == IPOPT_NOP) ? 1 : optbuf[i+1];
263			}
264		}
265	      }
266#endif
267		if (do_rlogin(fromp) == 0)
268			authenticated++;
269	}
270	if (confirmed == 0) {
271		write(f, "", 1);
272		confirmed = 1;		/* we sent the null! */
273	}
274	netf = f;
275
276	pid = forkpty(&master, line, NULL, &win);
277	if (pid < 0) {
278		if (errno == ENOENT)
279			fatal(f, "Out of ptys", 0);
280		else
281			fatal(f, "Forkpty", 1);
282	}
283	if (pid == 0) {
284		if (f > 2)	/* f should always be 0, but... */
285			(void) close(f);
286		setup_term(0);
287		 if (*lusername=='-') {
288			syslog(LOG_ERR, "tried to pass user \"%s\" to login",
289			       lusername);
290			fatal(STDERR_FILENO, "invalid user", 0);
291		}
292		if (authenticated) {
293			execl(_PATH_LOGIN, "login", "-p",
294			    "-h", hostname, "-f", lusername, (char *)NULL);
295		} else
296			execl(_PATH_LOGIN, "login", "-p",
297			    "-h", hostname, lusername, (char *)NULL);
298		fatal(STDERR_FILENO, _PATH_LOGIN, 1);
299		/*NOTREACHED*/
300	}
301	ioctl(f, FIONBIO, &on);
302	ioctl(master, FIONBIO, &on);
303	ioctl(master, TIOCPKT, &on);
304	signal(SIGCHLD, cleanup);
305	protocol(f, master);
306	signal(SIGCHLD, SIG_IGN);
307	cleanup(0);
308}
309
310char	magic[2] = { 0377, 0377 };
311char	oobdata[] = {TIOCPKT_WINDOW};
312
313/*
314 * Handle a "control" request (signaled by magic being present)
315 * in the data stream.  For now, we are only willing to handle
316 * window size changes.
317 */
318int
319control(int pty, char *cp, int n)
320{
321	struct winsize w;
322
323	if (n < 4 + (int)sizeof(w) || cp[2] != 's' || cp[3] != 's')
324		return (0);
325	oobdata[0] &= ~TIOCPKT_WINDOW;	/* we know he heard */
326	bcopy(cp+4, (char *)&w, sizeof(w));
327	w.ws_row = ntohs(w.ws_row);
328	w.ws_col = ntohs(w.ws_col);
329	w.ws_xpixel = ntohs(w.ws_xpixel);
330	w.ws_ypixel = ntohs(w.ws_ypixel);
331	(void)ioctl(pty, TIOCSWINSZ, &w);
332	return (4+sizeof (w));
333}
334
335/*
336 * rlogin "protocol" machine.
337 */
338void
339protocol(int f, int p)
340{
341	char pibuf[1024+1], fibuf[1024], *pbp = NULL, *fbp = NULL;
342	int pcc = 0, fcc = 0;
343	int cc, nfd, n;
344	char cntl;
345
346	/*
347	 * Must ignore SIGTTOU, otherwise we'll stop
348	 * when we try and set slave pty's window shape
349	 * (our controlling tty is the master pty).
350	 */
351	(void) signal(SIGTTOU, SIG_IGN);
352	send(f, oobdata, 1, MSG_OOB);	/* indicate new rlogin */
353	if (f > p)
354		nfd = f + 1;
355	else
356		nfd = p + 1;
357	if (nfd > FD_SETSIZE) {
358		syslog(LOG_ERR, "select mask too small, increase FD_SETSIZE");
359		fatal(f, "internal error (select mask too small)", 0);
360	}
361	for (;;) {
362		fd_set ibits, obits, ebits, *omask;
363
364		FD_ZERO(&ebits);
365		FD_ZERO(&ibits);
366		FD_ZERO(&obits);
367		omask = (fd_set *)NULL;
368		if (fcc) {
369			FD_SET(p, &obits);
370			omask = &obits;
371		} else
372			FD_SET(f, &ibits);
373		if (pcc >= 0) {
374			if (pcc) {
375				FD_SET(f, &obits);
376				omask = &obits;
377			} else
378				FD_SET(p, &ibits);
379		}
380		FD_SET(p, &ebits);
381		if ((n = select(nfd, &ibits, omask, &ebits, 0)) < 0) {
382			if (errno == EINTR)
383				continue;
384			fatal(f, "select", 1);
385		}
386		if (n == 0) {
387			/* shouldn't happen... */
388			sleep(5);
389			continue;
390		}
391#define	pkcontrol(c)	((c)&(TIOCPKT_FLUSHWRITE|TIOCPKT_NOSTOP|TIOCPKT_DOSTOP))
392		if (FD_ISSET(p, &ebits)) {
393			cc = read(p, &cntl, 1);
394			if (cc == 1 && pkcontrol(cntl)) {
395				cntl |= oobdata[0];
396				send(f, &cntl, 1, MSG_OOB);
397				if (cntl & TIOCPKT_FLUSHWRITE) {
398					pcc = 0;
399					FD_CLR(p, &ibits);
400				}
401			}
402		}
403		if (FD_ISSET(f, &ibits)) {
404			fcc = read(f, fibuf, sizeof(fibuf));
405			if (fcc < 0 && errno == EWOULDBLOCK)
406				fcc = 0;
407			else {
408				char *cp;
409				int left, n;
410
411				if (fcc <= 0)
412					break;
413				fbp = fibuf;
414
415			top:
416				for (cp = fibuf; cp < fibuf+fcc-1; cp++)
417					if (cp[0] == magic[0] &&
418					    cp[1] == magic[1]) {
419						left = fcc - (cp-fibuf);
420						n = control(p, cp, left);
421						if (n) {
422							left -= n;
423							if (left > 0)
424								bcopy(cp+n, cp, left);
425							fcc -= n;
426							goto top; /* n^2 */
427						}
428					}
429				FD_SET(p, &obits);		/* try write */
430			}
431		}
432
433		if (FD_ISSET(p, &obits) && fcc > 0) {
434			cc = write(p, fbp, fcc);
435			if (cc > 0) {
436				fcc -= cc;
437				fbp += cc;
438			}
439		}
440
441		if (FD_ISSET(p, &ibits)) {
442			pcc = read(p, pibuf, sizeof (pibuf));
443			pbp = pibuf;
444			if (pcc < 0 && errno == EWOULDBLOCK)
445				pcc = 0;
446			else if (pcc <= 0)
447				break;
448			else if (pibuf[0] == 0) {
449				pbp++, pcc--;
450				FD_SET(f, &obits);	/* try write */
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 ((FD_ISSET(f, &obits)) && pcc > 0) {
460			cc = write(f, pbp, pcc);
461			if (cc < 0 && errno == EWOULDBLOCK) {
462				/*
463				 * This happens when we try write after read
464				 * from p, but some old kernels balk at large
465				 * writes even when select returns true.
466				 */
467				if (!FD_ISSET(p, &ibits))
468					sleep(5);
469				continue;
470			}
471			if (cc > 0) {
472				pcc -= cc;
473				pbp += cc;
474			}
475		}
476	}
477}
478
479void
480cleanup(int signo __unused)
481{
482
483	shutdown(netf, SHUT_RDWR);
484	exit(1);
485}
486
487void
488fatal(int f, char *msg, int syserr)
489{
490	int len;
491	char buf[BUFSIZ], *bp = buf;
492
493	/*
494	 * Prepend binary one to message if we haven't sent
495	 * the magic null as confirmation.
496	 */
497	if (!confirmed)
498		*bp++ = '\01';		/* error indicator */
499	if (syserr)
500		len = snprintf(bp, sizeof(buf), "rlogind: %s: %s.\r\n",
501		    msg, strerror(errno));
502	else
503		len = snprintf(bp, sizeof(buf), "rlogind: %s.\r\n", msg);
504	if (len < 0)
505		len = 0;
506	(void) write(f, buf, bp + len - buf);
507	exit(1);
508}
509
510int
511do_rlogin(union sockunion *dest)
512{
513
514	getstr(rusername, sizeof(rusername), "remuser too long");
515	getstr(lusername, sizeof(lusername), "locuser too long");
516	getstr(term+ENVSIZE, sizeof(term)-ENVSIZE, "Terminal type too long");
517
518	pwd = getpwnam(lusername);
519	if (pwd == NULL)
520		return (-1);
521	/* XXX why don't we syslog() failure? */
522
523	return (iruserok_sa(dest, dest->su_len, pwd->pw_uid == 0, rusername,
524			    lusername));
525}
526
527void
528getstr(char *buf, int cnt, char *errmsg)
529{
530	char c;
531
532	do {
533		if (read(STDIN_FILENO, &c, 1) != 1)
534			exit(1);
535		if (--cnt < 0)
536			fatal(STDOUT_FILENO, errmsg, 0);
537		*buf++ = c;
538	} while (c != 0);
539}
540
541extern	char **environ;
542
543void
544setup_term(int fd)
545{
546	char *cp = index(term+ENVSIZE, '/');
547	char *speed;
548	struct termios tt, def;
549
550#ifndef notyet
551	tcgetattr(fd, &tt);
552	if (cp) {
553		*cp++ = '\0';
554		speed = cp;
555		cp = index(speed, '/');
556		if (cp)
557			*cp++ = '\0';
558		cfsetspeed(&tt, atoi(speed));
559	}
560
561	cfmakesane(&def);
562	tt.c_iflag = def.c_iflag;
563	tt.c_oflag = def.c_oflag;
564	tt.c_lflag = def.c_lflag;
565	tcsetattr(fd, TCSAFLUSH, &tt);
566#else
567	if (cp) {
568		*cp++ = '\0';
569		speed = cp;
570		cp = index(speed, '/');
571		if (cp)
572			*cp++ = '\0';
573		tcgetattr(fd, &tt);
574		cfsetspeed(&tt, atoi(speed));
575		tcsetattr(fd, TCSAFLUSH, &tt);
576	}
577#endif
578
579	env[0] = term;
580	env[1] = 0;
581	environ = env;
582}
583
584void
585usage(void)
586{
587	syslog(LOG_ERR, "usage: rlogind [-" ARGSTR "]");
588}
589