Ultrix-3.1/src/etc/rshd.c
/**********************************************************************
* Copyright (c) Digital Equipment Corporation 1984, 1985, 1986. *
* All Rights Reserved. *
* Reference "/usr/src/COPYRIGHT" for applicable restrictions. *
**********************************************************************/
#ifndef lint
static char sccsid[] = "@(#)rshd.c 3.0 (ULTRIX-11) 4/22/86";
/*
* Based on "@(#)rshd.c 1.2 (ULTRIX-32) 4/11/85";
* and "@(#)rshd.c 5.1 (Berkeley) 5/28/85";
*/
#endif
/*-----------------------------------------------------------------------
* Modification History
*
* 4/5/85 -- jrs
* Revise to allow inetd to perform front end functions,
* following the Berkeley model.
*
* Based on 4.2BSD labeled:
* rshd.c 4.21 84/09/13
*
*-----------------------------------------------------------------------
*/
/*
* remote shell server:
* remuser\0
* locuser\0
* command\0
* data
*/
#include <sys/ioctl.h>
#include <sys/param.h>
#ifdef pdp11
#define NCARGS 5120
#endif pdp11
#include <sys/socket.h>
#ifndef pdp11
#include <sys/wait.h>
#else pdp11
#include <wait.h>
#endif pdp11
#include <netinet/in.h>
#include <stdio.h>
#include <errno.h>
#include <pwd.h>
#include <signal.h>
#ifdef pdp11
#define sigset signal
#endif pdp11
#include <netdb.h>
#include <syslog.h>
int errno;
char *index(), *rindex();
/* VARARGS 1 */
int error();
main(argc, argv)
int argc;
char **argv;
{
struct linger linger;
int on = 1, fromlen;
struct sockaddr_in from;
fromlen = sizeof (from);
if (getpeername(0, &from, &fromlen) < 0) {
openlog(argv[0], LOG_PID);
syslog(LOG_ERR, "getpeername: %m");
closelog();
exit(1);
}
if (setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof (on)) < 0) {
openlog(argv[0], LOG_PID, 0);
syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
closelog();
}
linger.l_onoff = 1;
linger.l_linger = 60; /* XXX */
if (setsockopt(0, SOL_SOCKET, SO_LINGER, &linger, sizeof (linger)) < 0) {
openlog(argv[0], LOG_PID, 0);
syslog(LOG_WARNING, "setsockopt (SO_LINGER): %m");
closelog();
}
doit(dup(0), &from);
}
char username[20] = "USER=";
char homedir[64] = "HOME=";
char shell[64] = "SHELL=";
char *envinit[] =
{homedir, shell, "PATH=:/usr/ucb:/bin:/usr/bin", username, 0};
char **environ;
doit(f, fromp)
int f;
struct sockaddr_in *fromp;
{
char cmdbuf[NCARGS+1], *cp;
char locuser[16], remuser[16];
struct passwd *pwd;
int s, backoff;
struct hostent *hp;
short port;
int pv[2], pid, ready, readfrom, cc;
char buf[BUFSIZ], sig;
int one = 1;
(void) signal(SIGINT, SIG_DFL);
(void) signal(SIGQUIT, SIG_DFL);
(void) signal(SIGTERM, SIG_DFL);
#ifdef DEBUG
{ int t = open("/dev/tty", 2);
if (t >= 0) {
ioctl(t, TIOCNOTTY, (char *)0);
(void) close(t);
}
}
#endif
fromp->sin_port = ntohs((u_short)fromp->sin_port);
if (fromp->sin_family != AF_INET ||
fromp->sin_port >= IPPORT_RESERVED) {
openlog("rshd", LOG_PID, 0);
syslog(LOG_ERR, "malformed from address\n");
closelog();
exit(1);
}
(void) alarm(60);
port = 0;
for (;;) {
char c;
if (read(f, &c, 1) != 1) {
openlog("rshd", LOG_PID, 0);
syslog(LOG_ERR, "read: %m");
closelog();
(void) shutdown(f, 1+1);
exit(1);
}
if (c == 0)
break;
port = port * 10 + c - '0';
}
(void) alarm(0);
if (port != 0) {
int lport = IPPORT_RESERVED - 1, retryshift;
s = rresvport(&lport);
if (s < 0) {
openlog("rshd", LOG_PID, 0);
syslog(LOG_ERR, "can't get stderr port: %m");
closelog();
exit(1);
}
if (port >= IPPORT_RESERVED) {
openlog("rshd", LOG_PID, 0);
syslog(LOG_ERR, "2nd port not reserved\n");
closelog();
exit(1);
}
fromp->sin_port = htons((u_short)port);
if (connect(s, fromp, sizeof (*fromp)) < 0) {
openlog("rshd", LOG_PID, 0);
syslog(LOG_ERR, "connect: %m");
closelog();
exit(1);
}
}
dup2(f, 0);
dup2(f, 1);
dup2(f, 2);
hp = gethostbyaddr(&fromp->sin_addr, sizeof (struct in_addr),
fromp->sin_family);
if (hp == 0) {
error("Host name for your address unknown\n");
exit(1);
}
getstr(remuser, sizeof(remuser), "remuser");
getstr(locuser, sizeof(locuser), "locuser");
getstr(cmdbuf, sizeof(cmdbuf), "command");
setpwent();
pwd = getpwnam(locuser);
if (pwd == NULL) {
error("Login incorrect.\n");
exit(1);
}
endpwent();
if (chdir(pwd->pw_dir) < 0) {
chdir("/");
#ifdef notdef
error("No remote directory.\n");
exit(1);
#endif
}
if (ruserok(hp->h_name, pwd->pw_uid == 0, remuser, locuser) < 0) {
error("Permission denied.\n");
exit(1);
}
(void) write(2, "\0", 1);
if (port) {
if (pipe(pv) < 0) {
error("Can't make pipe.\n");
exit(1);
}
pid = fork();
if (pid == -1) {
error("Try again.\n");
exit(1);
}
if (pid) {
(void) close(0); (void) close(1); (void) close(2);
(void) close(f); (void) close(pv[1]);
readfrom = (1<<s) | (1<<pv[0]);
ioctl(pv[1], FIONBIO, (char *)&one);
/* should set s nbio! */
do {
ready = readfrom;
if (select(16, &ready, 0, 0, 0) < 0)
break;
if (ready & (1<<s)) {
if (read(s, &sig, 1) <= 0)
readfrom &= ~(1<<s);
else
killpg(pid, sig);
}
if (ready & (1<<pv[0])) {
errno = 0;
cc = read(pv[0], buf, sizeof (buf));
if (cc <= 0) {
shutdown(s, 1+1);
readfrom &= ~(1<<pv[0]);
} else
(void) write(s, buf, cc);
}
} while (readfrom);
exit(0);
}
setpgrp(0, getpid());
(void) close(s); (void) close(pv[0]);
dup2(pv[1], 2);
}
if (*pwd->pw_shell == '\0')
pwd->pw_shell = "/bin/sh";
(void) close(f);
(void) setgid(pwd->pw_gid);
#ifndef pdp11
initgroups(pwd->pw_name, pwd->pw_gid);
#endif pdp11
(void) setuid(pwd->pw_uid);
environ = envinit;
strncat(homedir, pwd->pw_dir, sizeof(homedir)-6);
strncat(shell, pwd->pw_shell, sizeof(shell)-7);
strncat(username, pwd->pw_name, sizeof(username)-6);
cp = rindex(pwd->pw_shell, '/');
if (cp)
cp++;
else
cp = pwd->pw_shell;
execl(pwd->pw_shell, cp, "-c", cmdbuf, 0);
perror(pwd->pw_shell);
exit(1);
protofail:
error("rsh: protocol failure detected by remote\n");
exit(1);
}
/* VARARGS 1 */
error(fmt)
char *fmt;
{
char buf[BUFSIZ];
buf[0] = 1;
(void) sprintf(buf+1, fmt);
(void) write(2, buf, strlen(buf));
}
getstr(buf, cnt, err)
char *buf;
int cnt;
char *err;
{
char c;
do {
if (read(0, &c, 1) != 1)
exit(1);
*buf++ = c;
if (--cnt == 0) {
error("%s too long\n", err);
exit(1);
}
} while (c != 0);
}