rlogind.c

早期freebsd实现

/*-
 * 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	8.1 (Berkeley) 6/4/93";
#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>
#include <termios.h>

#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

			execl(_PATH_LOGIN, "login", "-p",
			    "-h", hostname, "-f", lusername, (char *)NULL);
		} else
			execl(_PATH_LOGIN, "login", "-p",
			    "-h", hostname, lusername, (char *)NULL);
		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 */
	bcopy(cp+4, (char *)&w, 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;