add a man page from Chris Demetrios

[unix-history] / usr / src / libexec / rlogind / rlogind.c

/*-
 * Copyright (c) 1983, 1988, 1989, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * %sccs.include.redist.c%
 */

#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) %G%";
#endif /* not lint */

/*
 * remote login server:
 *	\0
 *	remuser\0
 *	locuser\0
 *	terminal_type/speed\0
 *	data
 *
 * Automatic login protocol is done here, using login -f upon success,
 * unless OLD_LOGIN is defined (then done in login, ala 4.2/4.3BSD).
 */

#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

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;
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 '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;
#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, "Couldn't get peer name of remote host: %m");
		fatalperror("Can't get peer name of remote host");
	}
	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;
#endif
	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);

	alarm(0);
	fromp->sin_port = ntohs((u_short)fromp->sin_port);
	hp = gethostbyaddr((char *)&fromp->sin_addr, sizeof(struct in_addr),

	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
#ifndef OLD_LOGIN
	{
		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);
		}
		if (do_rlogin(fromp) == 0)
			authenticated++;
	}
	if (confirmed == 0) {
		write(f, "", 1);
		confirmed = 1;		/* we sent the null! */
	}
#ifdef	KERBEROS
#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);
#ifdef OLD_LOGIN
		execl("/bin/login", "login", "-r", hp->h_name, 0);
#else /* OLD_LOGIN */
		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);
#endif /* OLD_LOGIN */
		fatal(STDERR_FILENO, _PATH_LOGIN, 1);
		/*NOTREACHED*/
	}
	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;
	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);
				}
			}
		}
			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--;
				obits |= fmask;	/* try a write */
			} else {
				if (pkcontrol(pibuf[0])) {
					pibuf[0] |= oobdata[0];
					send(f, &pibuf[0], 1, MSG_OOB);
				}
				pcc = 0;
			}
		}
			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);
}

#ifndef OLD_LOGIN
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);
}

extern	char **environ;

void
char *speeds[] = {
	"0", "50", "75", "110", "134", "150", "200", "300", "600",
	"1200", "1800", "2400", "4800", "9600", "19200", "38400",
};
#define	NSPEEDS	(sizeof(speeds) / sizeof(speeds[0]))

setup_term(fd)
	int fd;
{
	register char *cp = index(term, '/'), **cpp;
	char *speed;
#if BSD > 43
	struct termios tt;

	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, TCSADFLUSH, &tt);
#else
	struct sgttyb sgttyb;

	(void)ioctl(fd, TIOCGETP, &sgttyb);
	if (cp) {
		*cp++ = '\0';
		speed = cp;
		cp = index(speed, '/');
		if (cp)
			*cp++ = '\0';
		for (cpp = speeds; cpp < &speeds[NSPEEDS]; cpp++)
		    if (strcmp(*cpp, speed) == 0) {
			sgttyb.sg_ispeed = sgttyb.sg_ospeed = cpp - speeds;
			break;
		    }
	}
	sgttyb.sg_flags = ECHO|CRMOD|ANYP|XTABS;
	(void)ioctl(fd, TIOCSETP, &sgttyb);
#endif

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

/*
 * 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.
 */
local_domain(h)
	char *h;
{
	char localhost[MAXHOSTNAMELEN];
	char *p1, *p2, *topdomain();

	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);
}
#endif /* OLD_LOGIN */