NetBSD/usr.bin/rsh/rsh.c

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/* $NetBSD: rsh.c,v 1.12 1997/07/20 20:44:23 christos Exp $ */
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/*-
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* Copyright (c) 1983, 1990, 1993, 1994
* The Regents of the University of California. All rights reserved.
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*
* 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.
*/
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#include <sys/cdefs.h>
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#ifndef lint
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__COPYRIGHT("@(#) Copyright (c) 1983, 1990, 1993, 1994\n\
The Regents of the University of California. All rights reserved.\n");
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#endif /* not lint */
#ifndef lint
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#if 0
static char sccsid[] = "@(#)rsh.c 8.4 (Berkeley) 4/29/95";
#else
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__RCSID("$NetBSD: rsh.c,v 1.12 1997/07/20 20:44:23 christos Exp $");
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#endif
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#endif /* not lint */
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/file.h>
#include <poll.h>
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#include <netinet/in.h>
#include <netdb.h>
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#include <err.h>
#include <errno.h>
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#include <pwd.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
#ifdef __STDC__
#include <stdarg.h>
#else
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#include <varargs.h>
#endif
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#include "pathnames.h"
#ifdef KERBEROS
#include <kerberosIV/des.h>
#include <kerberosIV/krb.h>
CREDENTIALS cred;
Key_schedule schedule;
int use_kerberos = 1, doencrypt;
char dst_realm_buf[REALM_SZ], *dest_realm;
void warning __P((const char *, ...));
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#endif
/*
* rsh - remote shell
*/
extern char *__progname; /* XXX */
int remerr;
static int sigs[] = { SIGINT, SIGTERM, SIGQUIT };
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char *copyargs __P((char **));
void sendsig __P((int));
int checkfd __P((struct pollfd *, int));
void talk __P((int, sigset_t *, pid_t, int));
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void usage __P((void));
int main __P((int, char **));
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#ifdef IN_RCMD
int orcmd __P((char **, int, const char *,
const char *, const char *, int *));
#endif
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int
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main(argc, argv)
int argc;
char **argv;
{
struct passwd *pw;
struct servent *sp;
sigset_t oset, nset;
#ifdef IN_RCMD
char *locuser = 0, *loop;
#endif /* IN_RCMD */
int argoff, asrsh, ch, dflag, nflag, one, rem, i;
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pid_t pid;
uid_t uid;
char *args, *host, *p, *user, *name;
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argoff = asrsh = dflag = nflag = 0;
one = 1;
host = user = NULL;
#ifndef IN_RCMD
/*
* If called as something other than "rsh" use it as the host name,
* only for rsh.
*/
p = __progname;
if (strcmp(p, "rsh") == 0)
asrsh = 1;
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else
host = p;
#endif /* IN_RCMD */
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/* handle "rsh host flags" */
if (!host && argc > 2 && argv[1][0] != '-') {
host = argv[1];
argoff = 1;
}
#ifdef IN_RCMD
if ((loop = getenv("RCMD_LOOP")) && strcmp(loop, "YES") == 0)
warnx("rcmd appears to be looping!");
putenv("RCMD_LOOP=YES");
# ifdef KERBEROS
# ifdef CRYPT
# define OPTIONS "8KLdek:l:nu:wx"
# else
# define OPTIONS "8KLdek:l:nu:w"
# endif
# else
# define OPTIONS "8KLdel:nu:w"
# endif
#else /* IN_RCMD */
# ifdef KERBEROS
# ifdef CRYPT
# define OPTIONS "8KLdek:l:nwx"
# else
# define OPTIONS "8KLdek:l:nw"
# endif
# else
# define OPTIONS "8KLdel:nw"
# endif
#endif /* IN_RCMD */
if (!(pw = getpwuid(uid = getuid())))
errx(1, "unknown user id");
if ((name = strdup(pw->pw_name)) == NULL)
err(1, "malloc");
while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != -1)
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switch(ch) {
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 IN_RCMD
case 'u':
if (getuid() != 0 && optarg && name &&
strcmp(name, optarg) != 0)
errx(1,"only super user can use the -u option");
locuser = optarg;
break;
#endif /* IN_RCMD */
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#ifdef KERBEROS
#ifdef CRYPT
case 'x':
doencrypt = 1;
des_set_key((des_cblock *) cred.session, schedule);
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break;
#endif
#endif
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]) {
#ifdef IN_RCMD
usage();
#else
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if (asrsh)
*argv = "rlogin";
execv(_PATH_RLOGIN, argv);
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err(1, "can't exec %s", _PATH_RLOGIN);
#endif
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}
argc -= optind;
argv += optind;
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/* Accept user1@host format, though "-l user2" overrides user1 */
p = strchr(host, '@');
if (p) {
*p = '\0';
if (!user && p > host)
user = host;
host = p + 1;
if (*host == '\0')
usage();
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}
if (!user)
user = name;
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#ifdef KERBEROS
#ifdef CRYPT
/* -x turns off -n */
if (doencrypt)
nflag = 0;
#endif
#endif
args = copyargs(argv);
sp = NULL;
#ifdef KERBEROS
if (use_kerberos) {
sp = getservbyname((doencrypt ? "ekshell" : "kshell"), "tcp");
if (sp == NULL) {
use_kerberos = 0;
warning("can't get entry for %s/tcp service",
doencrypt ? "ekshell" : "kshell");
}
}
#endif
if (sp == NULL)
sp = getservbyname("shell", "tcp");
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if (sp == NULL)
errx(1, "shell/tcp: unknown service");
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#ifdef KERBEROS
try_connect:
if (use_kerberos) {
#if 1
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struct hostent *hp;
/* fully qualify hostname (needed for krb_realmofhost) */
hp = gethostbyname(host);
if (hp != NULL && !(host = strdup(hp->h_name)))
err(1, "strdup");
#endif
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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,
&remerr, dest_realm, &cred, schedule);
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else
#endif
rem = krcmd(&host, sp->s_port, user, args, &remerr,
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dest_realm);
if (rem < 0) {
use_kerberos = 0;
sp = getservbyname("shell", "tcp");
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if (sp == NULL)
errx(1, "shell/tcp: unknown service");
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if (errno == ECONNREFUSED)
warning("remote host doesn't support Kerberos");
if (errno == ENOENT)
warning("can't provide Kerberos auth data");
goto try_connect;
}
} else {
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if (doencrypt)
errx(1, "the -x flag requires Kerberos authentication.");
#ifdef IN_RCMD
rem = orcmd(&host, sp->s_port, locuser ? locuser :
#else
rem = rcmd(&host, sp->s_port,
#endif
name,
user, args, &remerr);
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}
#else /* KERBEROS */
#ifdef IN_RCMD
rem = orcmd(&host, sp->s_port, locuser ? locuser :
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#else
rem = rcmd(&host, sp->s_port,
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#endif
name, user, args, &remerr);
#endif /* KERBEROS */
(void)free(name);
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if (rem < 0)
exit(1);
if (remerr < 0)
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errx(1, "can't establish stderr");
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if (dflag) {
if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one,
sizeof(one)) < 0)
warn("setsockopt remote");
if (setsockopt(remerr, SOL_SOCKET, SO_DEBUG, &one,
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sizeof(one)) < 0)
warn("setsockopt stderr");
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}
(void) setuid(uid);
(void) sigemptyset(&nset);
for (i = 0; i < sizeof(sigs) / sizeof(sigs[0]); i++)
(void) sigaddset(&nset, sigs[i]);
(void) sigprocmask(SIG_BLOCK, &nset, &oset);
for (i = 0; i < sizeof(sigs) / sizeof(sigs[0]); i++) {
struct sigaction sa;
if (sa.sa_handler != SIG_IGN) {
sa.sa_handler = sendsig;
(void) sigaction(sigs[i], &sa, NULL);
}
}
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if (!nflag) {
pid = fork();
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if (pid < 0)
err(1, "fork");
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}
else
pid = -1;
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#if defined(KERBEROS) && defined(CRYPT)
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if (!doencrypt)
#endif
{
(void)ioctl(remerr, FIONBIO, &one);
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(void)ioctl(rem, FIONBIO, &one);
}
talk(nflag, &oset, pid, rem);
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if (!nflag)
(void)kill(pid, SIGKILL);
exit(0);
}
int
checkfd(fdp, outfd)
struct pollfd *fdp;
int outfd;
{
int nr, nw;
char buf[BUFSIZ];
if (fdp->revents & (POLLNVAL|POLLERR|POLLHUP))
return -1;
if ((fdp->revents & POLLIN) == 0)
return 0;
errno = 0;
#if defined(KERBEROS) && defined(CRYPT)
if (doencrypt)
nr = des_read(fdp->fd, buf, sizeof buf);
else
#endif
nr = read(fdp->fd, buf, sizeof buf);
if (nr <= 0) {
if (errno != EAGAIN)
return -1;
else
return 0;
}
else {
char *bc = buf;
while (nr) {
if ((nw = write(outfd, bc, nr)) <= 0)
return -1;
nr -= nw;
bc += nw;
}
return 0;
}
}
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void
talk(nflag, oset, pid, rem)
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int nflag;
sigset_t *oset;
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pid_t pid;
int rem;
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{
int nr, nw, nfds;
struct pollfd fds[2], *fdp = &fds[0];
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char *bp, buf[BUFSIZ];
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if (!nflag && pid == 0) {
(void)close(remerr);
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fdp->events = POLLOUT|POLLNVAL|POLLERR|POLLHUP;
fdp->fd = rem;
nr = 0;
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bp = buf;
for (;;) {
errno = 0;
if (nr == 0) {
if ((nr = read(0, buf, sizeof buf)) == 0)
goto done;
if (nr == -1) {
if (errno == EIO)
goto done;
if (errno == EINTR)
continue;
err(1, "read");
}
bp = buf;
}
rewrite: if (poll(fdp, 1, INFTIM) == -1) {
if (errno != EINTR)
err(1, "poll");
goto rewrite;
}
if (fdp->revents & (POLLNVAL|POLLERR|POLLHUP))
err(1, "poll");
if ((fdp->revents & POLLOUT) == 0)
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goto rewrite;
#if defined(KERBEROS) && defined(CRYPT)
if (doencrypt)
nw = des_write(rem, bp, nr);
else
#endif
nw = write(rem, bp, nr);
if (nw < 0) {
if (errno == EAGAIN)
continue;
err(1, "write");
}
bp += nw;
nr -= nw;
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}
done:
(void)shutdown(rem, 1);
exit(0);
}
(void) sigprocmask(SIG_SETMASK, oset, NULL);
fds[0].events = fds[1].events = POLLIN|POLLNVAL|POLLERR|POLLHUP;
fds[0].fd = remerr;
fds[1].fd = rem;
fdp = &fds[0];
nfds = 2;
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do {
if (poll(fdp, nfds, INFTIM) == -1) {
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if (errno != EINTR)
err(1, "poll");
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continue;
}
if (fds[0].events != 0 && checkfd(&fds[0], 2) == -1) {
nfds--;
fds[0].events = 0;
fdp = &fds[1];
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}
if (fds[1].events != 0 && checkfd(&fds[1], 1) == -1) {
nfds--;
fds[1].events = 0;
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}
}
while (nfds);
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}
void
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sendsig(sig)
int sig;
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{
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char signo;
signo = sig;
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#ifdef KERBEROS
#ifdef CRYPT
if (doencrypt)
(void)des_write(remerr, &signo, 1);
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else
#endif
#endif
(void)write(remerr, &signo, 1);
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}
#ifdef KERBEROS
/* VARARGS */
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void
#ifdef __STDC__
warning(const char *fmt, ...)
#else
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warning(va_alist)
va_dcl
#endif
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{
va_list ap;
#ifndef __STDC__
const char *fmt;
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va_start(ap);
fmt = va_arg(ap, const char *);
#else
va_start(ap, fmt);
#endif
(void) fprintf(stderr, "%s: warning, using standard rsh: ", __progname);
(void) vfprintf(stderr, fmt, ap);
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va_end(ap);
(void) fprintf(stderr, ".\n");
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}
#endif
char *
copyargs(argv)
char **argv;
{
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int cc;
char **ap, *args, *p;
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cc = 0;
for (ap = argv; *ap; ++ap)
cc += strlen(*ap) + 1;
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if (!(args = malloc((u_int)cc)))
err(1, "malloc");
for (p = args, *p = '\0', ap = argv; *ap; ++ap) {
(void)strcpy(p, *ap);
p += strlen(p);
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if (ap[1])
*p++ = ' ';
}
*p = '\0';
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return (args);
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}
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void
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usage()
{
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(void)fprintf(stderr,
"usage: %s [-nd%s]%s[-l login]%s [login@]host %s\n", __progname,
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#ifdef KERBEROS
#ifdef CRYPT
"x", " [-k realm] ",
#else
"", " [-k realm] ",
#endif
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#else
"", " ",
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#endif
#ifdef IN_RCMD
" [-u locuser]", "command"
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#else
"", "[command]"
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#endif
);
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exit(1);
}