[apple/network_cmds.git] / rlogind.tproj / rlogind.c

/*
 * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * "Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
 * Reserved.  This file contains Original Code and/or Modifications of
 * Original Code as defined in and that are subject to the Apple Public
 * Source License Version 1.0 (the 'License').  You may not use this file
 * except in compliance with the License.  Please obtain a copy of the
 * License at http://www.apple.com/publicsource and read it before using
 * this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License."
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*-
 * Copyright (c) 1983, 1988, 1989, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char copyright[] =
"@(#) Copyright (c) 1983, 1988, 1989, 1993\n\
	The Regents of the University of California.  All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)rlogind.c	8.2 (Berkeley) 4/28/95";
#endif /* not lint */

/*
 * remote login server:
 *	\0
 *	remuser\0
 *	locuser\0
 *	terminal_type/speed\0
 *	data
 */

#define	FD_SETSIZE	16		/* don't need many bits for select */
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <signal.h>
#ifdef __APPLE__
#include <sys/termios.h>
#else
#include <termios.h>
#endif

#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <arpa/inet.h>
#include <netdb.h>

#include <pwd.h>
#include <syslog.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include "pathnames.h"

#ifndef TIOCPKT_WINDOW
#define TIOCPKT_WINDOW 0x80
#endif

#ifdef	KERBEROS
#include <kerberosIV/des.h>
#include <kerberosIV/krb.h>
#define	SECURE_MESSAGE "This rlogin session is using DES encryption for all transmissions.\r\n"

AUTH_DAT	*kdata;
KTEXT		ticket;
u_char		auth_buf[sizeof(AUTH_DAT)];
u_char		tick_buf[sizeof(KTEXT_ST)];
Key_schedule	schedule;
int		doencrypt, retval, use_kerberos, vacuous;

#define		ARGSTR			"alnkvx"
#else
#define		ARGSTR			"aln"
#endif	/* KERBEROS */

char	*env[2];
#define	NMAX 30
char	lusername[NMAX+1], rusername[NMAX+1];
static	char term[64] = "TERM=";
#define	ENVSIZE	(sizeof("TERM=")-1)	/* skip null for concatenation */
int	keepalive = 1;
int	check_all = 0;

struct	passwd *pwd;

void	doit __P((int, struct sockaddr_in *));
int	control __P((int, char *, int));
void	protocol __P((int, int));
void	cleanup __P((int));
void	fatal __P((int, char *, int));
int	do_rlogin __P((struct sockaddr_in *));
void	getstr __P((char *, int, char *));
void	setup_term __P((int));
int	do_krb_login __P((struct sockaddr_in *));
void	usage __P((void));
int	local_domain __P((char *));
char	*topdomain __P((char *));

int
main(argc, argv)
	int argc;
	char *argv[];
{
	extern int __check_rhosts_file;
	struct sockaddr_in from;
	int ch, fromlen, on;

	openlog("rlogind", LOG_PID | LOG_CONS, LOG_AUTH);

	opterr = 0;
	while ((ch = getopt(argc, argv, ARGSTR)) != EOF)
		switch (ch) {
		case 'a':
			check_all = 1;
			break;
		case 'l':
			__check_rhosts_file = 0;
			break;
		case 'n':
			keepalive = 0;
			break;
#ifdef KERBEROS
		case 'k':
			use_kerberos = 1;
			break;
		case 'v':
			vacuous = 1;
			break;
#ifdef CRYPT
		case 'x':
			doencrypt = 1;
			break;
#endif
#endif
		case '?':
		default:
			usage();
			break;
		}
	argc -= optind;
	argv += optind;

#ifdef	KERBEROS
	if (use_kerberos && vacuous) {
		usage();
		fatal(STDERR_FILENO, "only one of -k and -v allowed", 0);
	}
#endif
	fromlen = sizeof (from);
	if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) {
		syslog(LOG_ERR,"Can't get peer name of remote host: %m");
		fatal(STDERR_FILENO, "Can't get peer name of remote host", 1);
	}
	on = 1;
	if (keepalive &&
	    setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof (on)) < 0)
		syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
	on = IPTOS_LOWDELAY;
	if (setsockopt(0, IPPROTO_IP, IP_TOS, (char *)&on, sizeof(int)) < 0)
		syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
	doit(0, &from);
}

int	child;
int	netf;
char	line[MAXPATHLEN];
int	confirmed;

struct winsize win = { 0, 0, 0, 0 };


void
doit(f, fromp)
	int f;
	struct sockaddr_in *fromp;
{
	int master, pid, on = 1;
	int authenticated = 0;
	register struct hostent *hp;
	char hostname[2 * MAXHOSTNAMELEN + 1];
	char c;

	alarm(60);
	read(f, &c, 1);

	if (c != 0)
		exit(1);
#ifdef	KERBEROS
	if (vacuous)
		fatal(f, "Remote host requires Kerberos authentication", 0);
#endif

	alarm(0);
	fromp->sin_port = ntohs((u_short)fromp->sin_port);
	hp = gethostbyaddr((char *)&fromp->sin_addr, sizeof(struct in_addr),
	    fromp->sin_family);
	if (hp)
		(void)strcpy(hostname, hp->h_name);
	else
		(void)strcpy(hostname, inet_ntoa(fromp->sin_addr));

#ifdef	KERBEROS
	if (use_kerberos) {
		retval = do_krb_login(fromp);
		if (retval == 0)
			authenticated++;
		else if (retval > 0)
			fatal(f, krb_err_txt[retval], 0);
		write(f, &c, 1);
		confirmed = 1;		/* we sent the null! */
	} else
#endif
	{
		if (fromp->sin_family != AF_INET ||
		    fromp->sin_port >= IPPORT_RESERVED ||
		    fromp->sin_port < IPPORT_RESERVED/2) {
			syslog(LOG_NOTICE, "Connection from %s on illegal port",
				inet_ntoa(fromp->sin_addr));
			fatal(f, "Permission denied", 0);
		}
#ifdef IP_OPTIONS
		{
		u_char optbuf[BUFSIZ/3], *cp;
		char lbuf[BUFSIZ], *lp;
		int optsize = sizeof(optbuf), ipproto;
		struct protoent *ip;

		if ((ip = getprotobyname("ip")) != NULL)
			ipproto = ip->p_proto;
		else
			ipproto = IPPROTO_IP;
		if (getsockopt(0, ipproto, IP_OPTIONS, (char *)optbuf,
		    &optsize) == 0 && optsize != 0) {
			lp = lbuf;
			for (cp = optbuf; optsize > 0; cp++, optsize--, lp += 3)
				sprintf(lp, " %2.2x", *cp);
			syslog(LOG_NOTICE,
			    "Connection received using IP options (ignored):%s",
			    lbuf);
			if (setsockopt(0, ipproto, IP_OPTIONS,
			    (char *)NULL, optsize) != 0) {
				syslog(LOG_ERR,
				    "setsockopt IP_OPTIONS NULL: %m");
				exit(1);
			}
		}
		}
#endif
		if (do_rlogin(fromp) == 0)
			authenticated++;
	}
	if (confirmed == 0) {
		write(f, "", 1);
		confirmed = 1;		/* we sent the null! */
	}
#ifdef	KERBEROS
#ifdef	CRYPT
	if (doencrypt)
		(void) des_write(f, SECURE_MESSAGE, sizeof(SECURE_MESSAGE) - 1);
#endif
#endif
	netf = f;

	pid = forkpty(&master, line, NULL, &win);
	if (pid < 0) {
		if (errno == ENOENT)
			fatal(f, "Out of ptys", 0);
		else
			fatal(f, "Forkpty", 1);
	}
	if (pid == 0) {
		if (f > 2)	/* f should always be 0, but... */
			(void) close(f);
		setup_term(0);
		if (authenticated) {
#ifdef	KERBEROS
			if (use_kerberos && (pwd->pw_uid == 0))
				syslog(LOG_INFO|LOG_AUTH,
				    "ROOT Kerberos login from %s.%s@%s on %s\n",
				    kdata->pname, kdata->pinst, kdata->prealm,
				    hostname);
#endif

			execle(_PATH_LOGIN, "login", "-p",
			    "-h", hostname, "-f", "--", lusername, NULL, env);
		} else
			execle(_PATH_LOGIN, "login", "-p",
			    "-h", hostname, "--", lusername, NULL, env);
		fatal(STDERR_FILENO, _PATH_LOGIN, 1);
		/*NOTREACHED*/
	}
#ifdef	CRYPT
#ifdef	KERBEROS
	/*
	 * If encrypted, don't turn on NBIO or the des read/write
	 * routines will croak.
	 */

	if (!doencrypt)
#endif
#endif
		ioctl(f, FIONBIO, &on);
	ioctl(master, FIONBIO, &on);
	ioctl(master, TIOCPKT, &on);
	signal(SIGCHLD, cleanup);
	protocol(f, master);
	signal(SIGCHLD, SIG_IGN);
	cleanup(0);
}

char	magic[2] = { 0377, 0377 };
char	oobdata[] = {TIOCPKT_WINDOW};

/*
 * Handle a "control" request (signaled by magic being present)
 * in the data stream.  For now, we are only willing to handle
 * window size changes.
 */
int
control(pty, cp, n)
	int pty;
	char *cp;
	int n;
{
	struct winsize w;

	if (n < 4+sizeof (w) || cp[2] != 's' || cp[3] != 's')
		return (0);
	oobdata[0] &= ~TIOCPKT_WINDOW;	/* we know he heard */
	memmove(&w, cp+4, sizeof(w));
	w.ws_row = ntohs(w.ws_row);
	w.ws_col = ntohs(w.ws_col);
	w.ws_xpixel = ntohs(w.ws_xpixel);
	w.ws_ypixel = ntohs(w.ws_ypixel);
	(void)ioctl(pty, TIOCSWINSZ, &w);
	return (4+sizeof (w));
}

/*
 * rlogin "protocol" machine.
 */
void
protocol(f, p)
	register int f, p;
{
	char pibuf[1024+1], fibuf[1024], *pbp, *fbp;
	register pcc = 0, fcc = 0;
	int cc, nfd, n;
	char cntl;

	/*
	 * Must ignore SIGTTOU, otherwise we'll stop
	 * when we try and set slave pty's window shape
	 * (our controlling tty is the master pty).
	 */
	(void) signal(SIGTTOU, SIG_IGN);
	send(f, oobdata, 1, MSG_OOB);	/* indicate new rlogin */
	if (f > p)
		nfd = f + 1;
	else
		nfd = p + 1;
	if (nfd > FD_SETSIZE) {
		syslog(LOG_ERR, "select mask too small, increase FD_SETSIZE");
		fatal(f, "internal error (select mask too small)", 0);
	}
	for (;;) {
		fd_set ibits, obits, ebits, *omask;

		FD_ZERO(&ebits);
		FD_ZERO(&ibits);
		FD_ZERO(&obits);
		omask = (fd_set *)NULL;
		if (fcc) {
			FD_SET(p, &obits);
			omask = &obits;
		} else
			FD_SET(f, &ibits);
		if (pcc >= 0)
			if (pcc) {
				FD_SET(f, &obits);
				omask = &obits;
			} else
				FD_SET(p, &ibits);
		FD_SET(p, &ebits);
		if ((n = select(nfd, &ibits, omask, &ebits, 0)) < 0) {
			if (errno == EINTR)
				continue;
			fatal(f, "select", 1);
		}
		if (n == 0) {
			/* shouldn't happen... */
			sleep(5);
			continue;
		}
#define	pkcontrol(c)	((c)&(TIOCPKT_FLUSHWRITE|TIOCPKT_NOSTOP|TIOCPKT_DOSTOP))
		if (FD_ISSET(p, &ebits)) {
			cc = read(p, &cntl, 1);
			if (cc == 1 && pkcontrol(cntl)) {
				cntl |= oobdata[0];
				send(f, &cntl, 1, MSG_OOB);
				if (cntl & TIOCPKT_FLUSHWRITE) {
					pcc = 0;
					FD_CLR(p, &ibits);
				}
			}
		}
		if (FD_ISSET(f, &ibits)) {
#ifdef	CRYPT
#ifdef	KERBEROS
			if (doencrypt)
				fcc = des_read(f, fibuf, sizeof(fibuf));
			else
#endif
#endif
				fcc = read(f, fibuf, sizeof(fibuf));
			if (fcc < 0 && errno == EWOULDBLOCK)
				fcc = 0;
			else {
				register char *cp;
				int left, n;

				if (fcc <= 0)
					break;
				fbp = fibuf;

			top:
				for (cp = fibuf; cp < fibuf+fcc-1; cp++)
					if (cp[0] == magic[0] &&
					    cp[1] == magic[1]) {
						left = fcc - (cp-fibuf);
						n = control(p, cp, left);
						if (n) {
							left -= n;
							if (left > 0)
								bcopy(cp+n, cp, left);
							fcc -= n;
							goto top; /* n^2 */
						}
					}
				FD_SET(p, &obits);		/* try write */
			}
		}

		if (FD_ISSET(p, &obits) && fcc > 0) {
			cc = write(p, fbp, fcc);
			if (cc > 0) {
				fcc -= cc;
				fbp += cc;
			}
		}

		if (FD_ISSET(p, &ibits)) {
			pcc = read(p, pibuf, sizeof (pibuf));
			pbp = pibuf;
			if (pcc < 0 && errno == EWOULDBLOCK)
				pcc = 0;
			else if (pcc <= 0)
				break;
			else if (pibuf[0] == 0) {
				pbp++, pcc--;
#ifdef	CRYPT
#ifdef	KERBEROS
				if (!doencrypt)
#endif
#endif
					FD_SET(f, &obits);	/* try write */
			} else {
				if (pkcontrol(pibuf[0])) {
					pibuf[0] |= oobdata[0];
					send(f, &pibuf[0], 1, MSG_OOB);
				}
				pcc = 0;
			}
		}
		if ((FD_ISSET(f, &obits)) && pcc > 0) {
#ifdef	CRYPT
#ifdef	KERBEROS
			if (doencrypt)
				cc = des_write(f, pbp, pcc);
			else
#endif
#endif
				cc = write(f, pbp, pcc);
			if (cc < 0 && errno == EWOULDBLOCK) {
				/*
				 * This happens when we try write after read
				 * from p, but some old kernels balk at large
				 * writes even when select returns true.
				 */
				if (!FD_ISSET(p, &ibits))
					sleep(5);
				continue;
			}
			if (cc > 0) {
				pcc -= cc;
				pbp += cc;
			}
		}
	}
}

void
cleanup(signo)
	int signo;
{
	char *p;

	p = line + sizeof(_PATH_DEV) - 1;
	if (logout(p))
		logwtmp(p, "", "");
	(void)chmod(line, 0666);
	(void)chown(line, 0, 0);
	*p = 'p';
	(void)chmod(line, 0666);
	(void)chown(line, 0, 0);
	shutdown(netf, 2);
	exit(1);
}

void
fatal(f, msg, syserr)
	int f;
	char *msg;
	int syserr;
{
	int len;
	char buf[BUFSIZ], *bp = buf;

	/*
	 * Prepend binary one to message if we haven't sent
	 * the magic null as confirmation.
	 */
	if (!confirmed)
		*bp++ = '\01';		/* error indicator */
	if (syserr)
		len = sprintf(bp, "rlogind: %s: %s.\r\n",
		    msg, strerror(errno));
	else
		len = sprintf(bp, "rlogind: %s.\r\n", msg);
	(void) write(f, buf, bp + len - buf);
	exit(1);
}

int
do_rlogin(dest)
	struct sockaddr_in *dest;
{
	getstr(rusername, sizeof(rusername), "remuser too long");
	getstr(lusername, sizeof(lusername), "locuser too long");
	getstr(term+ENVSIZE, sizeof(term)-ENVSIZE, "Terminal type too long");

	pwd = getpwnam(lusername);
	if (pwd == NULL)
		return (-1);
	if (pwd->pw_uid == 0)
		return (-1);
	/* XXX why don't we syslog() failure? */
	return (iruserok(dest->sin_addr.s_addr, 0, rusername, lusername));
}

void
getstr(buf, cnt, errmsg)
	char *buf;
	int cnt;
	char *errmsg;
{
	char c;

	do {
		if (read(0, &c, 1) != 1)
			exit(1);
		if (--cnt < 0)
			fatal(STDOUT_FILENO, errmsg, 0);
		*buf++ = c;
	} while (c != 0);
}

void
setup_term(fd)
	int fd;
{
	register char *cp = index(term+ENVSIZE, '/');
	char *speed;
	struct termios tt;

#ifndef notyet
	tcgetattr(fd, &tt);
	if (cp) {
		*cp++ = '\0';
		speed = cp;
		cp = index(speed, '/');
		if (cp)
			*cp++ = '\0';
		cfsetspeed(&tt, atoi(speed));
	}

	tt.c_iflag = TTYDEF_IFLAG;
	tt.c_oflag = TTYDEF_OFLAG;
	tt.c_lflag = TTYDEF_LFLAG;
	tcsetattr(fd, TCSAFLUSH, &tt);
#else
	if (cp) {
		*cp++ = '\0';
		speed = cp;
		cp = index(speed, '/');
		if (cp)
			*cp++ = '\0';
		tcgetattr(fd, &tt);
		cfsetspeed(&tt, atoi(speed));
		tcsetattr(fd, TCSAFLUSH, &tt);
	}
#endif

	env[0] = term;
	env[1] = 0;
}

#ifdef	KERBEROS
#define	VERSION_SIZE	9

/*
 * Do the remote kerberos login to the named host with the
 * given inet address
 *
 * Return 0 on valid authorization
 * Return -1 on valid authentication, no authorization
 * Return >0 for error conditions
 */
int
do_krb_login(dest)
	struct sockaddr_in *dest;
{
	int rc;
	char instance[INST_SZ], version[VERSION_SIZE];
	long authopts = 0L;	/* !mutual */
	struct sockaddr_in faddr;

	kdata = (AUTH_DAT *) auth_buf;
	ticket = (KTEXT) tick_buf;

	instance[0] = '*';
	instance[1] = '\0';

#ifdef	CRYPT
	if (doencrypt) {
		rc = sizeof(faddr);
		if (getsockname(0, (struct sockaddr *)&faddr, &rc))
			return (-1);
		authopts = KOPT_DO_MUTUAL;
		rc = krb_recvauth(
			authopts, 0,
			ticket, "rcmd",
			instance, dest, &faddr,
			kdata, "", schedule, version);
		 des_set_key(kdata->session, schedule);

	} else
#endif
		rc = krb_recvauth(
			authopts, 0,
			ticket, "rcmd",
			instance, dest, (struct sockaddr_in *) 0,
			kdata, "", (bit_64 *) 0, version);

	if (rc != KSUCCESS)
		return (rc);

	getstr(lusername, sizeof(lusername), "locuser");
	/* get the "cmd" in the rcmd protocol */
	getstr(term+ENVSIZE, sizeof(term)-ENVSIZE, "Terminal type");

	pwd = getpwnam(lusername);
	if (pwd == NULL)
		return (-1);

	/* returns nonzero for no access */
	if (kuserok(kdata, lusername) != 0)
		return (-1);
	
	return (0);

}
#endif /* KERBEROS */

void
usage()
{
#ifdef KERBEROS
	syslog(LOG_ERR, "usage: rlogind [-aln] [-k | -v]");
#else
	syslog(LOG_ERR, "usage: rlogind [-aln]");
#endif
}

/*
 * Check whether host h is in our local domain,
 * defined as sharing the last two components of the domain part,
 * or the entire domain part if the local domain has only one component.
 * If either name is unqualified (contains no '.'),
 * assume that the host is local, as it will be
 * interpreted as such.
 */
int
local_domain(h)
	char *h;
{
	char localhost[MAXHOSTNAMELEN];
	char *p1, *p2;

	localhost[0] = 0;
	(void) gethostname(localhost, sizeof(localhost));
	p1 = topdomain(localhost);
	p2 = topdomain(h);
	if (p1 == NULL || p2 == NULL || !strcasecmp(p1, p2))
		return (1);
	return (0);
}

char *
topdomain(h)
	char *h;
{
	register char *p;
	char *maybe = NULL;
	int dots = 0;

	for (p = h + strlen(h); p >= h; p--) {
		if (*p == '.') {
			if (++dots == 2)
				return (p);
			maybe = p;
		}
	}
	return (maybe);
}
Commit	Line	Data
b7080c8e A	1	/*
	2	* Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
921c0aec A	6	* "Portions Copyright (c) 1999 Apple Computer, Inc. All Rights
	7	* Reserved. This file contains Original Code and/or Modifications of
	8	* Original Code as defined in and that are subject to the Apple Public
	9	* Source License Version 1.0 (the 'License'). You may not use this file
	10	* except in compliance with the License. Please obtain a copy of the
	11	* License at http://www.apple.com/publicsource and read it before using
	12	* this file.
b7080c8e A	13	*
	14	* The Original Code and all software distributed under the License are
	15	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	16	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	17	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
921c0aec A	18	* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
	19	* License for the specific language governing rights and limitations
	20	* under the License."
b7080c8e A	21	*
	22	* @APPLE_LICENSE_HEADER_END@
	23	*/
	24	/*-
	25	* Copyright (c) 1983, 1988, 1989, 1993
	26	* The Regents of the University of California. All rights reserved.
	27	*
	28	* Redistribution and use in source and binary forms, with or without
	29	* modification, are permitted provided that the following conditions
	30	* are met:
	31	* 1. Redistributions of source code must retain the above copyright
	32	* notice, this list of conditions and the following disclaimer.
	33	* 2. Redistributions in binary form must reproduce the above copyright
	34	* notice, this list of conditions and the following disclaimer in the
	35	* documentation and/or other materials provided with the distribution.
	36	* 3. All advertising materials mentioning features or use of this software
	37	* must display the following acknowledgement:
	38	* This product includes software developed by the University of
	39	* California, Berkeley and its contributors.
	40	* 4. Neither the name of the University nor the names of its contributors
	41	* may be used to endorse or promote products derived from this software
	42	* without specific prior written permission.
	43	*
	44	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	45	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	46	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	47	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	48	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	49	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	50	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	51	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	52	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	53	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	54	* SUCH DAMAGE.
	55	*/
	56
	57	#ifndef lint
	58	static char copyright[] =
	59	"@(#) Copyright (c) 1983, 1988, 1989, 1993\n\
	60	The Regents of the University of California. All rights reserved.\n";
	61	#endif /* not lint */
	62
	63	#ifndef lint
	64	static char sccsid[] = "@(#)rlogind.c 8.2 (Berkeley) 4/28/95";
	65	#endif /* not lint */
	66
	67	/*
	68	* remote login server:
	69	* \0
	70	* remuser\0
	71	* locuser\0
	72	* terminal_type/speed\0
	73	* data
	74	*/
	75
	76	#define FD_SETSIZE 16 /* don't need many bits for select */
	77	#include <sys/param.h>
	78	#include <sys/stat.h>
	79	#include <sys/ioctl.h>
	80	#include <signal.h>
	81	#ifdef __APPLE__
	82	#include <sys/termios.h>
	83	#else
	84	#include <termios.h>
85	#endif
86
87	#include <sys/socket.h>
88	#include <netinet/in.h>
89	#include <netinet/in_systm.h>
90	#include <netinet/ip.h>
91	#include <arpa/inet.h>
92	#include <netdb.h>
93
94	#include <pwd.h>
95	#include <syslog.h>
96	#include <errno.h>
97	#include <stdio.h>
98	#include <unistd.h>
99	#include <stdlib.h>
100	#include <string.h>
101	#include "pathnames.h"
102
103	#ifndef TIOCPKT_WINDOW
104	#define TIOCPKT_WINDOW 0x80
105	#endif
106
107	#ifdef KERBEROS
108	#include <kerberosIV/des.h>
109	#include <kerberosIV/krb.h>
110	#define SECURE_MESSAGE "This rlogin session is using DES encryption for all transmissions.\r\n"
111
112	AUTH_DAT *kdata;
113	KTEXT ticket;
114	u_char auth_buf[sizeof(AUTH_DAT)];
115	u_char tick_buf[sizeof(KTEXT_ST)];
116	Key_schedule schedule;
117	int doencrypt, retval, use_kerberos, vacuous;
118
119	#define ARGSTR "alnkvx"
120	#else
121	#define ARGSTR "aln"
122	#endif /* KERBEROS */
123
124	char *env[2];
125	#define NMAX 30
126	char lusername[NMAX+1], rusername[NMAX+1];
127	static char term[64] = "TERM=";
128	#define ENVSIZE (sizeof("TERM=")-1) /* skip null for concatenation */
129	int keepalive = 1;
130	int check_all = 0;
131
132	struct passwd *pwd;
133
134	void doit __P((int, struct sockaddr_in *));
135	int control __P((int, char *, int));
136	void protocol __P((int, int));
137	void cleanup __P((int));
138	void fatal __P((int, char *, int));
139	int do_rlogin __P((struct sockaddr_in *));
140	void getstr __P((char , int, char ));
141	void setup_term __P((int));
142	int do_krb_login __P((struct sockaddr_in *));
143	void usage __P((void));
144	int local_domain __P((char *));
145	char topdomain __P((char ));
146
147	int
148	main(argc, argv)
149	int argc;
150	char *argv[];
151	{
152	extern int __check_rhosts_file;
153	struct sockaddr_in from;
154	int ch, fromlen, on;
155
156	openlog("rlogind", LOG_PID \| LOG_CONS, LOG_AUTH);
157
158	opterr = 0;
159	while ((ch = getopt(argc, argv, ARGSTR)) != EOF)
160	switch (ch) {
161	case 'a':
162	check_all = 1;
163	break;
164	case 'l':
165	__check_rhosts_file = 0;
166	break;
167	case 'n':
168	keepalive = 0;
169	break;
170	#ifdef KERBEROS
171	case 'k':
172	use_kerberos = 1;
173	break;
174	case 'v':
175	vacuous = 1;
176	break;
177	#ifdef CRYPT
178	case 'x':
179	doencrypt = 1;
180	break;
181	#endif
182	#endif
183	case '?':
184	default:
185	usage();
186	break;
187	}
188	argc -= optind;
189	argv += optind;
190
191	#ifdef KERBEROS
192	if (use_kerberos && vacuous) {
193	usage();
194	fatal(STDERR_FILENO, "only one of -k and -v allowed", 0);
195	}
196	#endif
197	fromlen = sizeof (from);
198	if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) {
199	syslog(LOG_ERR,"Can't get peer name of remote host: %m");
200	fatal(STDERR_FILENO, "Can't get peer name of remote host", 1);
201	}
202	on = 1;
203	if (keepalive &&
204	setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof (on)) < 0)
205	syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
206	on = IPTOS_LOWDELAY;
207	if (setsockopt(0, IPPROTO_IP, IP_TOS, (char *)&on, sizeof(int)) < 0)
208	syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
209	doit(0, &from);
210	}
211
212	int child;
213	int netf;
214	char line[MAXPATHLEN];
215	int confirmed;
216
217	struct winsize win = { 0, 0, 0, 0 };
218
219
220	void
221	doit(f, fromp)
222	int f;
223	struct sockaddr_in *fromp;
224	{
225	int master, pid, on = 1;
226	int authenticated = 0;
227	register struct hostent *hp;
228	char hostname[2 * MAXHOSTNAMELEN + 1];
229	char c;
230
231	alarm(60);
232	read(f, &c, 1);
233
234	if (c != 0)
235	exit(1);
236	#ifdef KERBEROS
237	if (vacuous)
238	fatal(f, "Remote host requires Kerberos authentication", 0);
239	#endif
240
241	alarm(0);
242	fromp->sin_port = ntohs((u_short)fromp->sin_port);
243	hp = gethostbyaddr((char *)&fromp->sin_addr, sizeof(struct in_addr),
244	fromp->sin_family);
245	if (hp)
246	(void)strcpy(hostname, hp->h_name);
247	else
248	(void)strcpy(hostname, inet_ntoa(fromp->sin_addr));
249
250	#ifdef KERBEROS
251	if (use_kerberos) {
252	retval = do_krb_login(fromp);
253	if (retval == 0)
254	authenticated++;
255	else if (retval > 0)
256	fatal(f, krb_err_txt[retval], 0);
257	write(f, &c, 1);
258	confirmed = 1; /* we sent the null! */
259	} else
260	#endif
261	{
262	if (fromp->sin_family != AF_INET \|\|
263	fromp->sin_port >= IPPORT_RESERVED \|\|
264	fromp->sin_port < IPPORT_RESERVED/2) {
265	syslog(LOG_NOTICE, "Connection from %s on illegal port",
266	inet_ntoa(fromp->sin_addr));
267	fatal(f, "Permission denied", 0);
268	}
269	#ifdef IP_OPTIONS
270	{
271	u_char optbuf[BUFSIZ/3], *cp;
272	char lbuf[BUFSIZ], *lp;
273	int optsize = sizeof(optbuf), ipproto;
274	struct protoent *ip;
275
276	if ((ip = getprotobyname("ip")) != NULL)
277	ipproto = ip->p_proto;
278	else
279	ipproto = IPPROTO_IP;
280	if (getsockopt(0, ipproto, IP_OPTIONS, (char *)optbuf,
281	&optsize) == 0 && optsize != 0) {
282	lp = lbuf;
283	for (cp = optbuf; optsize > 0; cp++, optsize--, lp += 3)
284	sprintf(lp, " %2.2x", *cp);
285	syslog(LOG_NOTICE,
286	"Connection received using IP options (ignored):%s",
287	lbuf);
288	if (setsockopt(0, ipproto, IP_OPTIONS,
289	(char *)NULL, optsize) != 0) {
290	syslog(LOG_ERR,
291	"setsockopt IP_OPTIONS NULL: %m");
292	exit(1);
293	}
294	}
295	}
296	#endif
297	if (do_rlogin(fromp) == 0)
298	authenticated++;
299	}
300	if (confirmed == 0) {
301	write(f, "", 1);
302	confirmed = 1; /* we sent the null! */
303	}
304	#ifdef KERBEROS
305	#ifdef CRYPT
306	if (doencrypt)
307	(void) des_write(f, SECURE_MESSAGE, sizeof(SECURE_MESSAGE) - 1);
308	#endif
309	#endif
310	netf = f;
311
312	pid = forkpty(&master, line, NULL, &win);
313	if (pid < 0) {
314	if (errno == ENOENT)
315	fatal(f, "Out of ptys", 0);
316	else
317	fatal(f, "Forkpty", 1);
318	}
319	if (pid == 0) {
320	if (f > 2) /* f should always be 0, but... */
321	(void) close(f);
322	setup_term(0);
323	if (authenticated) {
324	#ifdef KERBEROS
325	if (use_kerberos && (pwd->pw_uid == 0))
326	syslog(LOG_INFO\|LOG_AUTH,
327	"ROOT Kerberos login from %s.%s@%s on %s\n",
328	kdata->pname, kdata->pinst, kdata->prealm,
329	hostname);
330	#endif
331
332	execle(_PATH_LOGIN, "login", "-p",
333	"-h", hostname, "-f", "--", lusername, NULL, env);
334	} else
335	execle(_PATH_LOGIN, "login", "-p",
336	"-h", hostname, "--", lusername, NULL, env);
337	fatal(STDERR_FILENO, _PATH_LOGIN, 1);
338	/NOTREACHED/
339	}
340	#ifdef CRYPT
341	#ifdef KERBEROS
342	/*
343	* If encrypted, don't turn on NBIO or the des read/write
344	* routines will croak.
345	*/
346
347	if (!doencrypt)
348	#endif
349	#endif
350	ioctl(f, FIONBIO, &on);
351	ioctl(master, FIONBIO, &on);
352	ioctl(master, TIOCPKT, &on);
353	signal(SIGCHLD, cleanup);
354	protocol(f, master);
355	signal(SIGCHLD, SIG_IGN);
356	cleanup(0);
357	}
358
359	char magic[2] = { 0377, 0377 };
360	char oobdata[] = {TIOCPKT_WINDOW};
361
362	/*
363	* Handle a "control" request (signaled by magic being present)
364	* in the data stream. For now, we are only willing to handle
365	* window size changes.
366	*/
367	int
368	control(pty, cp, n)
369	int pty;
370	char *cp;
371	int n;
372	{
373	struct winsize w;
374
375	if (n < 4+sizeof (w) \|\| cp[2] != 's' \|\| cp[3] != 's')
376	return (0);
377	oobdata[0] &= ~TIOCPKT_WINDOW; /* we know he heard */
378	memmove(&w, cp+4, sizeof(w));
379	w.ws_row = ntohs(w.ws_row);
380	w.ws_col = ntohs(w.ws_col);
381	w.ws_xpixel = ntohs(w.ws_xpixel);
382	w.ws_ypixel = ntohs(w.ws_ypixel);
383	(void)ioctl(pty, TIOCSWINSZ, &w);
384	return (4+sizeof (w));
385	}
386
387	/*
388	* rlogin "protocol" machine.
389	*/
390	void
391	protocol(f, p)
392	register int f, p;
393	{
394	char pibuf[1024+1], fibuf[1024], pbp, fbp;
395	register pcc = 0, fcc = 0;
396	int cc, nfd, n;
397	char cntl;
398
399	/*
400	* Must ignore SIGTTOU, otherwise we'll stop
401	* when we try and set slave pty's window shape
402	* (our controlling tty is the master pty).
403	*/
404	(void) signal(SIGTTOU, SIG_IGN);
405	send(f, oobdata, 1, MSG_OOB); /* indicate new rlogin */
406	if (f > p)
407	nfd = f + 1;
408	else
409	nfd = p + 1;
410	if (nfd > FD_SETSIZE) {
411	syslog(LOG_ERR, "select mask too small, increase FD_SETSIZE");
412	fatal(f, "internal error (select mask too small)", 0);
413	}
414	for (;;) {
415	fd_set ibits, obits, ebits, *omask;
416
417	FD_ZERO(&ebits);
418	FD_ZERO(&ibits);
419	FD_ZERO(&obits);
420	omask = (fd_set *)NULL;
421	if (fcc) {
422	FD_SET(p, &obits);
423	omask = &obits;
424	} else
425	FD_SET(f, &ibits);
426	if (pcc >= 0)
427	if (pcc) {
428	FD_SET(f, &obits);
429	omask = &obits;
430	} else
431	FD_SET(p, &ibits);
432	FD_SET(p, &ebits);
433	if ((n = select(nfd, &ibits, omask, &ebits, 0)) < 0) {
434	if (errno == EINTR)
435	continue;
436	fatal(f, "select", 1);
437	}
438	if (n == 0) {
439	/* shouldn't happen... */
440	sleep(5);
441	continue;
442	}
443	#define pkcontrol(c) ((c)&(TIOCPKT_FLUSHWRITE\|TIOCPKT_NOSTOP\|TIOCPKT_DOSTOP))
444	if (FD_ISSET(p, &ebits)) {
445	cc = read(p, &cntl, 1);
446	if (cc == 1 && pkcontrol(cntl)) {
447	cntl \|= oobdata[0];
448	send(f, &cntl, 1, MSG_OOB);
449	if (cntl & TIOCPKT_FLUSHWRITE) {
450	pcc = 0;
451	FD_CLR(p, &ibits);
452	}
453	}
454	}
455	if (FD_ISSET(f, &ibits)) {
456	#ifdef CRYPT
457	#ifdef KERBEROS
458	if (doencrypt)
459	fcc = des_read(f, fibuf, sizeof(fibuf));
460	else
461	#endif
462	#endif
463	fcc = read(f, fibuf, sizeof(fibuf));
464	if (fcc < 0 && errno == EWOULDBLOCK)
465	fcc = 0;
466	else {
467	register char *cp;
468	int left, n;
469
470	if (fcc <= 0)
471	break;
472	fbp = fibuf;
473
474	top:
475	for (cp = fibuf; cp < fibuf+fcc-1; cp++)
476	if (cp[0] == magic[0] &&
477	cp[1] == magic[1]) {
478	left = fcc - (cp-fibuf);
479	n = control(p, cp, left);
480	if (n) {
481	left -= n;
482	if (left > 0)
483	bcopy(cp+n, cp, left);
484	fcc -= n;
485	goto top; /* n^2 */
486	}
487	}
488	FD_SET(p, &obits); /* try write */
489	}
490	}
491
492	if (FD_ISSET(p, &obits) && fcc > 0) {
493	cc = write(p, fbp, fcc);
494	if (cc > 0) {
495	fcc -= cc;
496	fbp += cc;
497	}
498	}
499
500	if (FD_ISSET(p, &ibits)) {
501	pcc = read(p, pibuf, sizeof (pibuf));
502	pbp = pibuf;
503	if (pcc < 0 && errno == EWOULDBLOCK)
504	pcc = 0;
505	else if (pcc <= 0)
506	break;
507	else if (pibuf[0] == 0) {
508	pbp++, pcc--;
509	#ifdef CRYPT
510	#ifdef KERBEROS
511	if (!doencrypt)
512	#endif
513	#endif
514	FD_SET(f, &obits); /* try write */
515	} else {
516	if (pkcontrol(pibuf[0])) {
517	pibuf[0] \|= oobdata[0];
518	send(f, &pibuf[0], 1, MSG_OOB);
519	}
520	pcc = 0;
521	}
522	}
523	if ((FD_ISSET(f, &obits)) && pcc > 0) {
524	#ifdef CRYPT
525	#ifdef KERBEROS
526	if (doencrypt)
527	cc = des_write(f, pbp, pcc);
528	else
529	#endif
530	#endif
531	cc = write(f, pbp, pcc);
532	if (cc < 0 && errno == EWOULDBLOCK) {
533	/*
534	* This happens when we try write after read
535	* from p, but some old kernels balk at large
536	* writes even when select returns true.
537	*/
538	if (!FD_ISSET(p, &ibits))
539	sleep(5);
540	continue;
541	}
542	if (cc > 0) {
543	pcc -= cc;
544	pbp += cc;
545	}
546	}
547	}
548	}
549
550	void
551	cleanup(signo)
552	int signo;
553	{
554	char *p;
555
556	p = line + sizeof(_PATH_DEV) - 1;
557	if (logout(p))
558	logwtmp(p, "", "");
559	(void)chmod(line, 0666);
560	(void)chown(line, 0, 0);
561	*p = 'p';
562	(void)chmod(line, 0666);
563	(void)chown(line, 0, 0);
564	shutdown(netf, 2);
565	exit(1);
566	}
567
568	void
569	fatal(f, msg, syserr)
570	int f;
571	char *msg;
572	int syserr;
573	{
574	int len;
575	char buf[BUFSIZ], *bp = buf;
576
577	/*
578	* Prepend binary one to message if we haven't sent
579	* the magic null as confirmation.
580	*/
581	if (!confirmed)
582	bp++ = '\01'; / error indicator */
583	if (syserr)
584	len = sprintf(bp, "rlogind: %s: %s.\r\n",
585	msg, strerror(errno));
586	else
587	len = sprintf(bp, "rlogind: %s.\r\n", msg);
588	(void) write(f, buf, bp + len - buf);
589	exit(1);
590	}
591
592	int
593	do_rlogin(dest)
594	struct sockaddr_in *dest;
595	{
596	getstr(rusername, sizeof(rusername), "remuser too long");
597	getstr(lusername, sizeof(lusername), "locuser too long");
598	getstr(term+ENVSIZE, sizeof(term)-ENVSIZE, "Terminal type too long");
599
600	pwd = getpwnam(lusername);
601	if (pwd == NULL)
602	return (-1);
603	if (pwd->pw_uid == 0)
604	return (-1);
605	/* XXX why don't we syslog() failure? */
606	return (iruserok(dest->sin_addr.s_addr, 0, rusername, lusername));
607	}
608
609	void
610	getstr(buf, cnt, errmsg)
611	char *buf;
612	int cnt;
613	char *errmsg;
614	{
615	char c;
616
617	do {
618	if (read(0, &c, 1) != 1)
619	exit(1);
620	if (--cnt < 0)
621	fatal(STDOUT_FILENO, errmsg, 0);
622	*buf++ = c;
623	} while (c != 0);
624	}
625
626	void
627	setup_term(fd)
628	int fd;
629	{
630	register char *cp = index(term+ENVSIZE, '/');
631	char *speed;
632	struct termios tt;
633
634	#ifndef notyet
635	tcgetattr(fd, &tt);
636	if (cp) {
637	*cp++ = '\0';
638	speed = cp;
639	cp = index(speed, '/');
640	if (cp)
641	*cp++ = '\0';
642	cfsetspeed(&tt, atoi(speed));
643	}
644
645	tt.c_iflag = TTYDEF_IFLAG;
646	tt.c_oflag = TTYDEF_OFLAG;
647	tt.c_lflag = TTYDEF_LFLAG;
648	tcsetattr(fd, TCSAFLUSH, &tt);
649	#else
650	if (cp) {
651	*cp++ = '\0';
652	speed = cp;
653	cp = index(speed, '/');
654	if (cp)
655	*cp++ = '\0';
656	tcgetattr(fd, &tt);
657	cfsetspeed(&tt, atoi(speed));
658	tcsetattr(fd, TCSAFLUSH, &tt);
659	}
660	#endif
661
662	env[0] = term;
663	env[1] = 0;
664	}
665
666	#ifdef KERBEROS
667	#define VERSION_SIZE 9
668
669	/*
670	* Do the remote kerberos login to the named host with the
671	* given inet address
672	*
673	* Return 0 on valid authorization
674	* Return -1 on valid authentication, no authorization
675	* Return >0 for error conditions
676	*/
677	int
678	do_krb_login(dest)
679	struct sockaddr_in *dest;
680	{
681	int rc;
682	char instance[INST_SZ], version[VERSION_SIZE];
683	long authopts = 0L; /* !mutual */
684	struct sockaddr_in faddr;
685
686	kdata = (AUTH_DAT *) auth_buf;
687	ticket = (KTEXT) tick_buf;
688
689	instance[0] = '*';
690	instance[1] = '\0';
691
692	#ifdef CRYPT
693	if (doencrypt) {
694	rc = sizeof(faddr);
695	if (getsockname(0, (struct sockaddr *)&faddr, &rc))
696	return (-1);
697	authopts = KOPT_DO_MUTUAL;
698	rc = krb_recvauth(
699	authopts, 0,
700	ticket, "rcmd",
701	instance, dest, &faddr,
702	kdata, "", schedule, version);
703	des_set_key(kdata->session, schedule);
704
705	} else
706	#endif
707	rc = krb_recvauth(
708	authopts, 0,
709	ticket, "rcmd",
710	instance, dest, (struct sockaddr_in *) 0,
711	kdata, "", (bit_64 *) 0, version);
712
713	if (rc != KSUCCESS)
714	return (rc);
715
716	getstr(lusername, sizeof(lusername), "locuser");
717	/* get the "cmd" in the rcmd protocol */
718	getstr(term+ENVSIZE, sizeof(term)-ENVSIZE, "Terminal type");
719
720	pwd = getpwnam(lusername);
721	if (pwd == NULL)
722	return (-1);
723
724	/* returns nonzero for no access */
725	if (kuserok(kdata, lusername) != 0)
726	return (-1);
727
728	return (0);
729
730	}
731	#endif /* KERBEROS */
732
733	void
734	usage()
735	{
736	#ifdef KERBEROS
737	syslog(LOG_ERR, "usage: rlogind [-aln] [-k \| -v]");
738	#else
739	syslog(LOG_ERR, "usage: rlogind [-aln]");
740	#endif
741	}
742
743	/*
744	* Check whether host h is in our local domain,
745	* defined as sharing the last two components of the domain part,
746	* or the entire domain part if the local domain has only one component.
747	* If either name is unqualified (contains no '.'),
748	* assume that the host is local, as it will be
749	* interpreted as such.
750	*/
751	int
752	local_domain(h)
753	char *h;
754	{
755	char localhost[MAXHOSTNAMELEN];
756	char p1, p2;
757
758	localhost[0] = 0;
759	(void) gethostname(localhost, sizeof(localhost));
760	p1 = topdomain(localhost);
761	p2 = topdomain(h);
762	if (p1 == NULL \|\| p2 == NULL \|\| !strcasecmp(p1, p2))
763	return (1);
764	return (0);
765	}
766
767	char *
768	topdomain(h)
769	char *h;
770	{
771	register char *p;
772	char *maybe = NULL;
773	int dots = 0;
774
775	for (p = h + strlen(h); p >= h; p--) {
776	if (*p == '.') {
777	if (++dots == 2)
778	return (p);
779	maybe = p;
780	}
781	}
782	return (maybe);
783	}