FreeBSD-5.3/libexec/rlogind/rlogind.c
/*-
* Copyright (c) 1983, 1988, 1989, 1993
* The Regents of the University of California. All rights reserved.
* Copyright (c) 2002 Networks Associates Technology, Inc.
* All rights reserved.
*
* Portions of this software were developed for the FreeBSD Project by
* ThinkSec AS and NAI Labs, the Security Research Division of Network
* Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
* ("CBOSS"), as part of the DARPA CHATS research program.
*
* 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.
*/
#if 0
#ifndef lint
static const 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 const char sccsid[] = "@(#)rlogind.c 8.1 (Berkeley) 6/4/93";
#endif /* not lint */
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/libexec/rlogind/rlogind.c,v 1.40 2003/05/04 00:43:39 obrien Exp $");
/*
* 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/types.h>
#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 <netinet/tcp.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>
#include <libutil.h>
#include <paths.h>
#include <pwd.h>
#include <syslog.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#ifndef TIOCPKT_WINDOW
#define TIOCPKT_WINDOW 0x80
#endif
#define ARGSTR "Dalnx"
/* wrapper for KAME-special getnameinfo() */
#ifndef NI_WITHSCOPEID
#define NI_WITHSCOPEID 0
#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 no_delay;
struct passwd *pwd;
union sockunion {
struct sockinet {
u_char si_len;
u_char si_family;
u_short si_port;
} su_si;
struct sockaddr_in su_sin;
struct sockaddr_in6 su_sin6;
};
#define su_len su_si.si_len
#define su_family su_si.si_family
#define su_port su_si.si_port
void doit(int, union sockunion *);
int control(int, char *, int);
void protocol(int, int);
void cleanup(int);
void fatal(int, char *, int);
int do_rlogin(union sockunion *);
void getstr(char *, int, char *);
void setup_term(int);
int do_krb_login(struct sockaddr_in *);
void usage(void);
int
main(int argc, char *argv[])
{
extern int __check_rhosts_file;
union sockunion from;
int ch, fromlen, on;
openlog("rlogind", LOG_PID | LOG_CONS, LOG_AUTH);
opterr = 0;
while ((ch = getopt(argc, argv, ARGSTR)) != -1)
switch (ch) {
case 'D':
no_delay = 1;
break;
case 'a':
check_all = 1;
break;
case 'l':
__check_rhosts_file = 0;
break;
case 'n':
keepalive = 0;
break;
#ifdef CRYPT
case 'x':
doencrypt = 1;
break;
#endif
case '?':
default:
usage();
break;
}
argc -= optind;
argv += optind;
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");
if (no_delay &&
setsockopt(0, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on)) < 0)
syslog(LOG_WARNING, "setsockopt (TCP_NODELAY): %m");
if (from.su_family == AF_INET)
{
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);
return 0;
}
int child;
int netf;
char line[MAXPATHLEN];
int confirmed;
struct winsize win = { 0, 0, 0, 0 };
void
doit(int f, union sockunion *fromp)
{
int master, pid, on = 1;
int authenticated = 0;
char hostname[2 * MAXHOSTNAMELEN + 1];
char nameinfo[2 * INET6_ADDRSTRLEN + 1];
char c;
alarm(60);
read(f, &c, 1);
if (c != 0)
exit(1);
alarm(0);
realhostname_sa(hostname, sizeof(hostname) - 1,
(struct sockaddr *)fromp, fromp->su_len);
/* error check ? */
fromp->su_port = ntohs((u_short)fromp->su_port);
hostname[sizeof(hostname) - 1] = '\0';
{
if ((fromp->su_family != AF_INET
#ifdef INET6
&& fromp->su_family != AF_INET6
#endif
) ||
fromp->su_port >= IPPORT_RESERVED ||
fromp->su_port < IPPORT_RESERVED/2) {
getnameinfo((struct sockaddr *)fromp,
fromp->su_len,
nameinfo, sizeof(nameinfo), NULL, 0,
NI_NUMERICHOST|NI_WITHSCOPEID);
/* error check ? */
syslog(LOG_NOTICE, "Connection from %s on illegal port",
nameinfo);
fatal(f, "Permission denied", 0);
}
#ifdef IP_OPTIONS
if (fromp->su_family == AF_INET)
{
u_char optbuf[BUFSIZ/3];
int optsize = sizeof(optbuf), ipproto, i;
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) {
for (i = 0; i < optsize; ) {
u_char c = optbuf[i];
if (c == IPOPT_LSRR || c == IPOPT_SSRR) {
syslog(LOG_NOTICE,
"Connection refused from %s with IP option %s",
inet_ntoa(fromp->su_sin.sin_addr),
c == IPOPT_LSRR ? "LSRR" : "SSRR");
exit(1);
}
if (c == IPOPT_EOL)
break;
i += (c == IPOPT_NOP) ? 1 : optbuf[i+1];
}
}
}
#endif
if (do_rlogin(fromp) == 0)
authenticated++;
}
if (confirmed == 0) {
write(f, "", 1);
confirmed = 1; /* we sent the null! */
}
#ifdef CRYPT
if (doencrypt)
(void) des_enc_write(f,
SECURE_MESSAGE,
strlen(SECURE_MESSAGE),
schedule, &kdata->session);
#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 (*lusername=='-') {
syslog(LOG_ERR, "tried to pass user \"%s\" to login",
lusername);
fatal(STDERR_FILENO, "invalid user", 0);
}
if (authenticated) {
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
/*
* If encrypted, don't turn on NBIO or the des read/write
* routines will croak.
*/
if (!doencrypt)
#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(int pty, char *cp, int n)
{
struct winsize w;
if (n < 4 + (int)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(int f, int p)
{
char pibuf[1024+1], fibuf[1024], *pbp = NULL, *fbp = NULL;
int 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
if (doencrypt)
fcc = des_enc_read(f, fibuf, sizeof(fibuf),
schedule, &kdata->session);
else
#endif
fcc = read(f, fibuf, sizeof(fibuf));
if (fcc < 0 && errno == EWOULDBLOCK)
fcc = 0;
else {
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
if (!doencrypt)
#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
if (doencrypt)
cc = des_enc_write(f, pbp, pcc,
schedule, &kdata->session);
else
#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(int signo)
{
char *p;
p = line + sizeof(_PATH_DEV) - 1;
if (logout(p))
logwtmp(p, "", "");
(void)chflags(line, 0);
(void)chmod(line, 0666);
(void)chown(line, 0, 0);
*p = 'p';
(void)chflags(line, 0);
(void)chmod(line, 0666);
(void)chown(line, 0, 0);
shutdown(netf, 2);
exit(1);
}
void
fatal(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 = snprintf(bp, sizeof(buf), "rlogind: %s: %s.\r\n",
msg, strerror(errno));
else
len = snprintf(bp, sizeof(buf), "rlogind: %s.\r\n", msg);
if (len < 0)
len = 0;
(void) write(f, buf, bp + len - buf);
exit(1);
}
int
do_rlogin(union sockunion *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);
/* XXX why don't we syslog() failure? */
return (iruserok_sa(dest, dest->su_len, pwd->pw_uid == 0, rusername,
lusername));
}
void
getstr(char *buf, int cnt, char *errmsg)
{
char c;
do {
if (read(STDIN_FILENO, &c, 1) != 1)
exit(1);
if (--cnt < 0)
fatal(STDOUT_FILENO, errmsg, 0);
*buf++ = c;
} while (c != 0);
}
extern char **environ;
void
setup_term(int fd)
{
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;
environ = env;
}
void
usage(void)
{
syslog(LOG_ERR, "usage: rlogind [-" ARGSTR "]");
}