freebsd-dev/usr.bin/rsh/rsh.c
2002-09-09 16:14:03 +00:00

528 lines
11 KiB
C

/*-
* Copyright (c) 1983, 1990, 1993, 1994
* 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.
*/
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1983, 1990, 1993, 1994\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static const char sccsid[] = "From: @(#)rsh.c 8.3 (Berkeley) 4/6/94";
#endif /* not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/signal.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/file.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <netdb.h>
#include <err.h>
#include <errno.h>
#include <libutil.h>
#include <paths.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <err.h>
#ifdef KERBEROS
#include <openssl/des.h>
#include <krb.h>
#include "krb.h"
CREDENTIALS cred;
Key_schedule schedule;
int use_kerberos = 1, doencrypt;
char dst_realm_buf[REALM_SZ], *dest_realm;
extern char *krb_realmofhost();
#endif
/*
* rsh - remote shell
*/
int rfd2;
int family = PF_UNSPEC;
char rlogin[] = "rlogin";
void connect_timeout(int);
char *copyargs(char * const *);
void sendsig(int);
void talk(int, long, pid_t, int, int);
void usage(void);
int
main(int argc, char *argv[])
{
struct passwd const *pw;
struct servent const *sp;
long omask;
int argoff, asrsh, ch, dflag, nflag, one, rem;
pid_t pid = 0;
uid_t uid;
char *args, *host, *p, *user;
int timeout = 0;
#ifdef KERBEROS
const char *k;
#endif
argoff = asrsh = dflag = nflag = 0;
one = 1;
host = user = NULL;
/* if called as something other than "rsh", use it as the host name */
if ((p = strrchr(argv[0], '/')))
++p;
else
p = argv[0];
if (strcmp(p, "rsh"))
host = p;
else
asrsh = 1;
/* handle "rsh host flags" */
if (!host && argc > 2 && argv[1][0] != '-') {
host = argv[1];
argoff = 1;
}
#ifdef KERBEROS
#ifdef CRYPT
#define OPTIONS "468KLde:k:l:nt:wx"
#else
#define OPTIONS "468KLde:k:l:nt:w"
#endif
#else
#define OPTIONS "468KLde:l:nt:w"
#endif
while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != -1)
switch(ch) {
case '4':
family = PF_INET;
break;
case '6':
family = PF_INET6;
break;
case 'K':
#ifdef KERBEROS
use_kerberos = 0;
#endif
break;
case 'L': /* -8Lew are ignored to allow rlogin aliases */
case 'e':
case 'w':
case '8':
break;
case 'd':
dflag = 1;
break;
case 'l':
user = optarg;
break;
#ifdef KERBEROS
case 'k':
dest_realm = dst_realm_buf;
strncpy(dest_realm, optarg, REALM_SZ);
break;
#endif
case 'n':
nflag = 1;
break;
#ifdef KERBEROS
#ifdef CRYPT
case 'x':
doencrypt = 1;
break;
#endif
#endif
case 't':
timeout = atoi(optarg);
break;
case '?':
default:
usage();
}
optind += argoff;
/* if haven't gotten a host yet, do so */
if (!host && !(host = argv[optind++]))
usage();
/* if no further arguments, must have been called as rlogin. */
if (!argv[optind]) {
if (asrsh)
*argv = rlogin;
execv(_PATH_RLOGIN, argv);
err(1, "can't exec %s", _PATH_RLOGIN);
}
argc -= optind;
argv += optind;
if (!(pw = getpwuid(uid = getuid())))
errx(1, "unknown user id");
if (!user)
user = pw->pw_name;
#ifdef KERBEROS
#ifdef CRYPT
/* -x turns off -n */
if (doencrypt)
nflag = 0;
#endif
#endif
args = copyargs(argv);
sp = NULL;
#ifdef KERBEROS
k = auth_getval("auth_list");
if (k && !strstr(k, "kerberos"))
use_kerberos = 0;
if (use_kerberos) {
sp = getservbyname((doencrypt ? "ekshell" : "kshell"), "tcp");
if (sp == NULL) {
use_kerberos = 0;
warnx(
"warning, using standard rsh: can't get entry for %s/tcp service",
doencrypt ? "ekshell" : "kshell");
}
}
#endif
if (sp == NULL)
sp = getservbyname("shell", "tcp");
if (sp == NULL)
errx(1, "shell/tcp: unknown service");
#ifdef KERBEROS
try_connect:
if (use_kerberos) {
struct hostent *hp;
/* fully qualify hostname (needed for krb_realmofhost) */
hp = gethostbyname(host);
if (hp != NULL && !(host = strdup(hp->h_name)))
err(1, NULL);
rem = KSUCCESS;
errno = 0;
if (dest_realm == NULL)
dest_realm = krb_realmofhost(host);
#ifdef CRYPT
if (doencrypt) {
rem = krcmd_mutual(&host, sp->s_port, user, args,
&rfd2, dest_realm, &cred, schedule);
des_set_key(&cred.session, schedule);
} else
#endif
rem = krcmd(&host, sp->s_port, user, args, &rfd2,
dest_realm);
if (rem < 0) {
use_kerberos = 0;
sp = getservbyname("shell", "tcp");
if (sp == NULL)
errx(1, "shell/tcp: unknown service");
if (errno == ECONNREFUSED)
warnx(
"warning, using standard rsh: remote host doesn't support Kerberos");
if (errno == ENOENT)
warnx(
"warning, using standard rsh: can't provide Kerberos auth data");
goto try_connect;
}
} else {
if (doencrypt)
errx(1, "the -x flag requires Kerberos authentication");
rem = rcmd_af(&host, sp->s_port, pw->pw_name, user, args,
&rfd2, family);
}
#else
if (timeout) {
signal(SIGALRM, connect_timeout);
alarm(timeout);
}
rem = rcmd_af(&host, sp->s_port, pw->pw_name, user, args, &rfd2,
family);
if (timeout) {
signal(SIGALRM, SIG_DFL);
alarm(0);
}
#endif
if (rem < 0)
exit(1);
if (rfd2 < 0)
errx(1, "can't establish stderr");
if (dflag) {
if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one,
sizeof(one)) < 0)
warn("setsockopt");
if (setsockopt(rfd2, SOL_SOCKET, SO_DEBUG, &one,
sizeof(one)) < 0)
warn("setsockopt");
}
(void)setuid(uid);
omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGTERM));
if (signal(SIGINT, SIG_IGN) != SIG_IGN)
(void)signal(SIGINT, sendsig);
if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
(void)signal(SIGQUIT, sendsig);
if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
(void)signal(SIGTERM, sendsig);
if (!nflag) {
pid = fork();
if (pid < 0)
err(1, "fork");
}
else
(void)shutdown(rem, 1);
#ifdef KERBEROS
#ifdef CRYPT
if (!doencrypt)
#endif
#endif
{
(void)ioctl(rfd2, FIONBIO, &one);
(void)ioctl(rem, FIONBIO, &one);
}
talk(nflag, omask, pid, rem, timeout);
if (!nflag)
(void)kill(pid, SIGKILL);
exit(0);
}
void
talk(int nflag, long omask, pid_t pid, int rem, int timeout)
{
int cc, wc;
fd_set readfrom, ready, rembits;
char buf[BUFSIZ];
const char *bp;
struct timeval tvtimeout;
int nfds, srval;
if (!nflag && pid == 0) {
(void)close(rfd2);
reread: errno = 0;
if ((cc = read(0, buf, sizeof buf)) <= 0)
goto done;
bp = buf;
rewrite:
if (rem >= FD_SETSIZE)
errx(1, "descriptor too big");
FD_ZERO(&rembits);
FD_SET(rem, &rembits);
nfds = rem + 1;
if (select(nfds, 0, &rembits, 0, 0) < 0) {
if (errno != EINTR)
err(1, "select");
goto rewrite;
}
if (!FD_ISSET(rem, &rembits))
goto rewrite;
#ifdef KERBEROS
#ifdef CRYPT
if (doencrypt)
wc = des_enc_write(rem, bp, cc, schedule, &cred.session);
else
#endif
#endif
wc = write(rem, bp, cc);
if (wc < 0) {
if (errno == EWOULDBLOCK)
goto rewrite;
goto done;
}
bp += wc;
cc -= wc;
if (cc == 0)
goto reread;
goto rewrite;
done:
(void)shutdown(rem, 1);
exit(0);
}
tvtimeout.tv_sec = timeout;
tvtimeout.tv_usec = 0;
(void)sigsetmask(omask);
if (rfd2 >= FD_SETSIZE || rem >= FD_SETSIZE)
errx(1, "descriptor too big");
FD_ZERO(&readfrom);
FD_SET(rfd2, &readfrom);
FD_SET(rem, &readfrom);
nfds = MAX(rfd2+1, rem+1);
do {
ready = readfrom;
if (timeout) {
srval = select(nfds, &ready, 0, 0, &tvtimeout);
} else {
srval = select(nfds, &ready, 0, 0, 0);
}
if (srval < 0) {
if (errno != EINTR)
err(1, "select");
continue;
}
if (srval == 0)
errx(1, "timeout reached (%d seconds)\n", timeout);
if (FD_ISSET(rfd2, &ready)) {
errno = 0;
#ifdef KERBEROS
#ifdef CRYPT
if (doencrypt)
cc = des_enc_read(rfd2, buf, sizeof buf, schedule, &cred.session);
else
#endif
#endif
cc = read(rfd2, buf, sizeof buf);
if (cc <= 0) {
if (errno != EWOULDBLOCK)
FD_CLR(rfd2, &readfrom);
} else
(void)write(STDERR_FILENO, buf, cc);
}
if (FD_ISSET(rem, &ready)) {
errno = 0;
#ifdef KERBEROS
#ifdef CRYPT
if (doencrypt)
cc = des_enc_read(rem, buf, sizeof buf, schedule, &cred.session);
else
#endif
#endif
cc = read(rem, buf, sizeof buf);
if (cc <= 0) {
if (errno != EWOULDBLOCK)
FD_CLR(rem, &readfrom);
} else
(void)write(STDOUT_FILENO, buf, cc);
}
} while (FD_ISSET(rfd2, &readfrom) || FD_ISSET(rem, &readfrom));
}
void
connect_timeout(int sig)
{
char message[] = "timeout reached before connection completed.\n";
write(STDERR_FILENO, message, sizeof(message) - 1);
_exit(1);
}
void
sendsig(int sig)
{
char signo;
signo = sig;
#ifdef KERBEROS
#ifdef CRYPT
if (doencrypt)
(void)des_enc_write(rfd2, &signo, 1, schedule, &cred.session);
else
#endif
#endif
(void)write(rfd2, &signo, 1);
}
char *
copyargs(char * const *argv)
{
int cc;
char *args, *p;
char * const *ap;
cc = 0;
for (ap = argv; *ap; ++ap)
cc += strlen(*ap) + 1;
if (!(args = malloc((u_int)cc)))
err(1, NULL);
for (p = args, ap = argv; *ap; ++ap) {
(void)strcpy(p, *ap);
for (p = strcpy(p, *ap); *p; ++p);
if (ap[1])
*p++ = ' ';
}
return (args);
}
void
usage(void)
{
(void)fprintf(stderr,
"usage: rsh [-46] [-ndK%s]%s[-l login] [-t timeout] host [command]\n",
#ifdef KERBEROS
#ifdef CRYPT
"x", " [-k realm] ");
#else
"", " [-k realm] ");
#endif
#else
"", " ");
#endif
exit(1);
}