NetBSD/libexec/rlogind/rlogind.c

600 lines
13 KiB
C

/*-
* 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
/* from: static char sccsid[] = "@(#)rlogind.c 8.1 (Berkeley) 6/4/93"; */
static char *rcsid = "$Id: rlogind.c,v 1.8 1996/05/21 12:22:31 mrg Exp $";
#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 <utmp.h>
#include "pathnames.h"
#ifndef TIOCPKT_WINDOW
#define TIOCPKT_WINDOW 0x80
#endif
#define ARGSTR "aln"
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;
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");
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);
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 && (strlen(hp->h_name) <= UT_HOSTSIZE))
(void)strcpy(hostname, hp->h_name);
else
(void)strcpy(hostname, inet_ntoa(fromp->sin_addr));
{
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! */
}
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)
execl(_PATH_LOGIN, "login", "-p",
"-h", hostname, "-f", "--", lusername, (char *)0);
else
execl(_PATH_LOGIN, "login", "-p",
"-h", hostname, "--", lusername, (char *)0);
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);
}
}
}
if (FD_ISSET(f, &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--;
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) {
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);
}
extern char **environ;
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;
environ = env;
}
void
usage()
{
syslog(LOG_ERR, "usage: rlogind [-aln]");
}
/*
* 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);
}