OpenBSD-4.6/libexec/rshd/rshd.c
/* $OpenBSD: rshd.c,v 1.52 2008/04/08 19:16:05 deraadt Exp $ */
/*-
* Copyright (c) 1988, 1989, 1992, 1993, 1994
* 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. 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) 1988, 1989, 1992, 1993, 1994\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
/* from: static char sccsid[] = "@(#)rshd.c 8.2 (Berkeley) 4/6/94"; */
static char *rcsid = "$OpenBSD: rshd.c,v 1.52 2008/04/08 19:16:05 deraadt Exp $";
#endif /* not lint */
/*
* remote shell server:
* [port]\0
* remuser\0
* locuser\0
* command\0
* data
*/
#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <arpa/inet.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <paths.h>
#include <poll.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <stdarg.h>
#include <login_cap.h>
#include <bsd_auth.h>
int keepalive = 1;
int check_all;
int log_success; /* If TRUE, log all successful accesses */
int sent_null;
login_cap_t *lc;
void doit(struct sockaddr *);
void error(const char *, ...);
void getstr(char *, int, char *);
int local_domain(char *);
char *topdomain(char *);
void usage(void);
#ifdef KERBEROS
#include <des.h>
#include <kerberosIV/krb.h>
#define VERSION_SIZE 9
#define SECURE_MESSAGE "This rsh session is using DES encryption for all transmissions.\r\n"
#ifdef CRYPT
#define OPTIONS "alnkvxL"
#else
#define OPTIONS "alnkvL"
#endif
char authbuf[sizeof(AUTH_DAT)];
char tickbuf[sizeof(KTEXT_ST)];
int doencrypt, use_kerberos, vacuous;
des_key_schedule schedule;
#ifdef CRYPT
int des_read(int, char *, int);
int des_write(int, char *, int);
void desrw_clear_key();
void desrw_set_key(des_cblock *, des_key_schedule *);
#endif
#else
#define OPTIONS "alnL"
#endif
#define P_SOCKREAD 0
#define P_PIPEREAD 1
#define P_CRYPTREAD 2
#define P_CRYPTWRITE 3
int
main(int argc, char *argv[])
{
extern int __check_rhosts_file;
struct linger linger;
int ch, on = 1;
socklen_t fromlen;
struct sockaddr_storage from;
openlog("rshd", LOG_PID | LOG_ODELAY, LOG_DAEMON);
opterr = 0;
while ((ch = getopt(argc, argv, OPTIONS)) != -1)
switch (ch) {
case 'a':
check_all = 1;
break;
case 'l':
__check_rhosts_file = 0;
break;
case 'n':
keepalive = 0;
break;
#ifdef KERBEROS
case 'k':
use_kerberos = 1;
break;
case 'v':
vacuous = 1;
break;
#ifdef CRYPT
case 'x':
doencrypt = 1;
break;
#endif
#endif
case 'L':
log_success = 1;
break;
case '?':
default:
usage();
break;
}
argc -= optind;
argv += optind;
#ifdef KERBEROS
if (use_kerberos && vacuous) {
syslog(LOG_ERR, "only one of -k and -v allowed");
exit(2);
}
#ifdef CRYPT
if (doencrypt && !use_kerberos) {
syslog(LOG_ERR, "-k is required for -x");
exit(2);
}
#endif
#endif
fromlen = sizeof (from);
if (getpeername(STDIN_FILENO, (struct sockaddr *)&from, &fromlen) < 0) {
/* syslog(LOG_ERR, "getpeername: %m"); */
exit(1);
}
if (keepalive &&
setsockopt(STDIN_FILENO, SOL_SOCKET, SO_KEEPALIVE, (char *)&on,
sizeof(on)) < 0)
syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
linger.l_onoff = 1;
linger.l_linger = 60; /* XXX */
if (setsockopt(STDIN_FILENO, SOL_SOCKET, SO_LINGER, (char *)&linger,
sizeof (linger)) < 0)
syslog(LOG_WARNING, "setsockopt (SO_LINGER): %m");
doit((struct sockaddr *)&from);
/* NOTREACHED */
exit(0);
}
char *envinit[1] = { 0 };
extern char **environ;
void
doit(struct sockaddr *fromp)
{
extern char *__rcmd_errstr; /* syslog hook from libc/net/rcmd.c. */
struct addrinfo hints, *res, *res0;
int gaierror;
struct passwd *pwd;
u_short port;
in_port_t *portp;
struct pollfd pfd[4];
int cc, nfd, pv[2], s = 0, one = 1;
pid_t pid;
char *hostname, *errorstr, *errorhost = (char *) NULL;
char *cp, sig, buf[BUFSIZ];
char cmdbuf[NCARGS+1], locuser[_PW_NAME_LEN+1], remuser[_PW_NAME_LEN+1];
char remotehost[2 * MAXHOSTNAMELEN + 1];
char hostnamebuf[2 * MAXHOSTNAMELEN + 1];
char naddr[NI_MAXHOST];
char saddr[NI_MAXHOST];
char raddr[NI_MAXHOST];
char pbuf[NI_MAXSERV];
auth_session_t *as;
const int niflags = NI_NUMERICHOST | NI_NUMERICSERV;
#ifdef KERBEROS
AUTH_DAT *kdata = (AUTH_DAT *) NULL;
KTEXT ticket = (KTEXT) NULL;
char instance[INST_SZ], version[VERSION_SIZE];
struct sockaddr_storage fromaddr;
int rc;
long authopts;
#ifdef CRYPT
int pv1[2], pv2[2];
#endif
if (sizeof(fromaddr) < fromp->sa_len) {
syslog(LOG_ERR, "malformed \"from\" address (af %d)",
fromp->sa_family);
exit(1);
}
memcpy(&fromaddr, fromp, fromp->sa_len);
#endif
(void) signal(SIGINT, SIG_DFL);
(void) signal(SIGQUIT, SIG_DFL);
(void) signal(SIGTERM, SIG_DFL);
#ifdef DEBUG
{ int t = open(_PATH_TTY, 2);
if (t >= 0) {
ioctl(t, TIOCNOTTY, (char *)0);
(void) close(t);
}
}
#endif
switch (fromp->sa_family) {
case AF_INET:
portp = &((struct sockaddr_in *)fromp)->sin_port;
break;
case AF_INET6:
portp = &((struct sockaddr_in6 *)fromp)->sin6_port;
break;
default:
syslog(LOG_ERR, "malformed \"from\" address (af %d)",
fromp->sa_family);
exit(1);
}
if (getnameinfo(fromp, fromp->sa_len, naddr, sizeof(naddr),
pbuf, sizeof(pbuf), niflags) != 0) {
syslog(LOG_ERR, "malformed \"from\" address (af %d)",
fromp->sa_family);
exit(1);
}
#ifdef IP_OPTIONS
if (fromp->sa_family == AF_INET) {
struct ipoption opts;
socklen_t optsize = sizeof(opts);
int ipproto, i;
struct protoent *ip;
if ((ip = getprotobyname("ip")) != NULL)
ipproto = ip->p_proto;
else
ipproto = IPPROTO_IP;
if (!getsockopt(STDIN_FILENO, ipproto, IP_OPTIONS,
(char *)&opts, &optsize) && optsize != 0) {
for (i = 0; (void *)&opts.ipopt_list[i] - (void *)&opts <
optsize; ) {
u_char c = (u_char)opts.ipopt_list[i];
if (c == IPOPT_LSRR || c == IPOPT_SSRR)
exit(1);
if (c == IPOPT_EOL)
break;
i += (c == IPOPT_NOP) ? 1 :
(u_char)opts.ipopt_list[i+1];
}
}
}
#endif
#ifdef KERBEROS
if (!use_kerberos)
#endif
if (ntohs(*portp) >= IPPORT_RESERVED ||
ntohs(*portp) < IPPORT_RESERVED/2) {
syslog(LOG_NOTICE|LOG_AUTH,
"Connection from %s on illegal port %u",
naddr, ntohs(*portp));
exit(1);
}
(void) alarm(60);
port = 0;
for (;;) {
char c;
if ((cc = read(STDIN_FILENO, &c, 1)) != 1) {
if (cc < 0)
syslog(LOG_NOTICE, "read: %m");
shutdown(STDIN_FILENO, SHUT_RDWR);
exit(1);
}
if (c == 0)
break;
port = port * 10 + c - '0';
}
(void) alarm(0);
if (port != 0) {
int lport;
#ifdef KERBEROS
if (!use_kerberos)
#endif
if (port >= IPPORT_RESERVED ||
port < IPPORT_RESERVED/2) {
syslog(LOG_ERR, "2nd port not reserved");
exit(1);
}
*portp = htons(port);
lport = IPPORT_RESERVED - 1;
s = rresvport_af(&lport, fromp->sa_family);
if (s < 0) {
syslog(LOG_ERR, "can't get stderr port: %m");
exit(1);
}
if (connect(s, (struct sockaddr *)fromp, fromp->sa_len) < 0) {
syslog(LOG_INFO, "connect second port %d: %m", port);
exit(1);
}
}
#ifdef KERBEROS
if (vacuous) {
error("rshd: remote host requires Kerberos authentication\n");
exit(1);
}
#endif
#ifdef notdef
/* from inetd, socket is already on 0, 1, 2 */
dup2(f, 0);
dup2(f, 1);
dup2(f, 2);
#endif
errorstr = NULL;
if (getnameinfo(fromp, fromp->sa_len, saddr, sizeof(saddr),
NULL, 0, NI_NAMEREQD)== 0) {
/*
* If name returned by getnameinfo is in our domain,
* attempt to verify that we haven't been fooled by someone
* in a remote net; look up the name and check that this
* address corresponds to the name.
*/
hostname = saddr;
res0 = NULL;
#ifdef KERBEROS
if (!use_kerberos)
#endif
if (check_all || local_domain(saddr)) {
strlcpy(remotehost, saddr, sizeof(remotehost));
errorhost = remotehost;
memset(&hints, 0, sizeof(hints));
hints.ai_family = fromp->sa_family;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_CANONNAME;
gaierror = getaddrinfo(remotehost, pbuf, &hints, &res0);
if (gaierror) {
syslog(LOG_INFO,
"Couldn't look up address for %s: %s",
remotehost, gai_strerror(gaierror));
errorstr =
"Couldn't look up address for your host (%s)\n";
hostname = naddr;
} else {
for (res = res0; res; res = res->ai_next) {
if (res->ai_family != fromp->sa_family)
continue;
if (res->ai_addrlen != fromp->sa_len)
continue;
if (getnameinfo(res->ai_addr,
res->ai_addrlen,
raddr, sizeof(raddr), NULL, 0,
niflags) == 0
&& strcmp(naddr, raddr) == 0) {
hostname = res->ai_canonname
? res->ai_canonname
: saddr;
break;
}
}
if (res == NULL) {
syslog(LOG_NOTICE,
"Host addr %s not listed for host %s",
naddr, res0->ai_canonname
? res0->ai_canonname
: saddr);
errorstr =
"Host address mismatch for %s\n";
hostname = naddr;
}
}
}
strlcpy(hostnamebuf, hostname, sizeof(hostnamebuf));
hostname = hostnamebuf;
if (res0)
freeaddrinfo(res0);
} else
strlcpy(hostnamebuf, naddr, sizeof(hostnamebuf));
errorhost = hostname = hostnamebuf;
#ifdef KERBEROS
if (use_kerberos) {
kdata = (AUTH_DAT *) authbuf;
ticket = (KTEXT) tickbuf;
authopts = 0L;
strlcpy(instance, "*", sizeof instance);
version[VERSION_SIZE - 1] = '\0';
#ifdef CRYPT
if (doencrypt) {
struct sockaddr_in local_addr;
rc = sizeof(local_addr);
if (getsockname(STDIN_FILENO,
(struct sockaddr *)&local_addr, &rc) < 0) {
syslog(LOG_ERR, "getsockname: %m");
error("rshd: getsockname: %m");
exit(1);
}
authopts = KOPT_DO_MUTUAL;
rc = krb_recvauth(authopts, 0, ticket,
"rcmd", instance, (struct sockaddr_in *)&fromaddr,
&local_addr, kdata, "", schedule, version);
desrw_set_key(&kdata->session, &schedule);
} else
#endif
rc = krb_recvauth(authopts, 0, ticket, "rcmd",
instance, (struct sockaddr_in *)&fromaddr,
NULL, kdata, "", NULL, version);
if (rc != KSUCCESS) {
error("Kerberos authentication failure: %s\n",
krb_get_err_text(rc));
exit(1);
}
} else
#endif
getstr(remuser, sizeof(remuser), "remuser");
getstr(locuser, sizeof(locuser), "locuser");
getstr(cmdbuf, sizeof(cmdbuf), "command");
pwd = getpwnam(locuser);
if (pwd == NULL) {
syslog(LOG_INFO|LOG_AUTH,
"%s@%s as %s: unknown login. cmd='%.80s'",
remuser, hostname, locuser, cmdbuf);
if (errorstr == NULL)
errorstr = "Permission denied.\n";
goto fail;
}
lc = login_getclass(pwd->pw_class);
if (lc == NULL) {
syslog(LOG_INFO|LOG_AUTH,
"%s@%s as %s: unknown class. cmd='%.80s'",
remuser, hostname, locuser, cmdbuf);
if (errorstr == NULL)
errorstr = "Login incorrect.\n";
goto fail;
}
as = auth_open();
if (as == NULL || auth_setpwd(as, pwd) != 0) {
syslog(LOG_INFO|LOG_AUTH,
"%s@%s as %s: unable to allocate memory. cmd='%.80s'",
remuser, hostname, locuser, cmdbuf);
if (errorstr == NULL)
errorstr = "Cannot allocate memory.\n";
goto fail;
}
setegid(pwd->pw_gid);
seteuid(pwd->pw_uid);
if (chdir(pwd->pw_dir) < 0) {
(void) chdir("/");
#ifdef notdef
syslog(LOG_INFO|LOG_AUTH,
"%s@%s as %s: no home directory. cmd='%.80s'",
remuser, hostname, locuser, cmdbuf);
error("No remote directory.\n");
exit(1);
#endif
}
seteuid(0);
setegid(0); /* XXX use a saved gid instead? */
#ifdef KERBEROS
if (use_kerberos) {
if (pwd->pw_passwd != 0 && *pwd->pw_passwd != '\0') {
if (kuserok(kdata, locuser) != 0) {
syslog(LOG_INFO|LOG_AUTH,
"Kerberos rsh denied to %s.%s@%s",
kdata->pname, kdata->pinst, kdata->prealm);
error("Permission denied.\n");
exit(1);
}
}
} else
#endif
if (errorstr ||
(pwd->pw_passwd != 0 && *pwd->pw_passwd != '\0' &&
iruserok_sa(fromp, fromp->sa_len, pwd->pw_uid == 0,
remuser, locuser) < 0)) {
if (__rcmd_errstr)
syslog(LOG_INFO|LOG_AUTH,
"%s@%s as %s: permission denied (%s). cmd='%.80s'",
remuser, hostname, locuser, __rcmd_errstr,
cmdbuf);
else
syslog(LOG_INFO|LOG_AUTH,
"%s@%s as %s: permission denied. cmd='%.80s'",
remuser, hostname, locuser, cmdbuf);
fail:
if (errorstr == NULL)
errorstr = "Permission denied.\n";
error(errorstr, errorhost);
exit(1);
}
if (pwd->pw_uid)
auth_checknologin(lc);
(void) write(STDERR_FILENO, "\0", 1);
sent_null = 1;
if (port) {
if (pipe(pv) < 0) {
error("Can't make pipe.\n");
exit(1);
}
#ifdef CRYPT
#ifdef KERBEROS
if (doencrypt) {
if (pipe(pv1) < 0) {
error("Can't make 2nd pipe.\n");
exit(1);
}
if (pipe(pv2) < 0) {
error("Can't make 3rd pipe.\n");
exit(1);
}
}
#endif
#endif
pid = fork();
if (pid == -1) {
error("Can't fork; try again.\n");
exit(1);
}
if (pid) {
#ifdef CRYPT
#ifdef KERBEROS
if (doencrypt) {
static char msg[] = SECURE_MESSAGE;
(void) close(pv1[1]);
(void) close(pv2[1]);
des_write(s, msg, sizeof(msg) - 1);
} else
#endif
#endif
{
(void) close(STDIN_FILENO);
(void) close(STDOUT_FILENO);
}
(void) close(STDERR_FILENO);
(void) close(pv[1]);
pfd[P_SOCKREAD].fd = s;
pfd[P_SOCKREAD].events = POLLIN;
pfd[P_PIPEREAD].fd = pv[0];
pfd[P_PIPEREAD].events = POLLIN;
nfd = 2;
#ifdef CRYPT
#ifdef KERBEROS
if (doencrypt) {
pfd[P_CRYPTREAD].fd = pv1[0];
pfd[P_CRYPTREAD].events = POLLIN;
pfd[P_CRYPTWRITE].fd = pv2[0];
pfd[P_CRYPTWRITE].events = POLLOUT;
nfd += 2;
} else
#endif
#endif
ioctl(pv[0], FIONBIO, (char *)&one);
/* should set s nbio! */
do {
if (poll(pfd, nfd, INFTIM) < 0)
break;
if (pfd[P_SOCKREAD].revents & POLLIN) {
int ret;
#ifdef CRYPT
#ifdef KERBEROS
if (doencrypt)
ret = des_read(s, &sig, 1);
else
#endif
#endif
ret = read(s, &sig, 1);
if (ret <= 0)
pfd[P_SOCKREAD].revents = 0;
else
killpg(pid, sig);
}
if (pfd[P_PIPEREAD].revents & POLLIN) {
errno = 0;
cc = read(pv[0], buf, sizeof(buf));
if (cc <= 0) {
shutdown(s, SHUT_RDWR);
pfd[P_PIPEREAD].revents = 0;
} else {
#ifdef CRYPT
#ifdef KERBEROS
if (doencrypt)
(void)
des_write(s, buf, cc);
else
#endif
#endif
(void)
write(s, buf, cc);
}
}
#ifdef CRYPT
#ifdef KERBEROS
if (doencrypt &&
(pfd[P_CRYPTREAD].revents & POLLIN)) {
errno = 0;
cc = read(pv1[0], buf, sizeof(buf));
if (cc <= 0) {
shutdown(pv1[0], SHUT_RDWR);
pfd[P_CRYPTREAD].revents = 0;
} else
(void) des_write(STDOUT_FILENO,
buf, cc);
}
if (doencrypt &&
(pfd[P_CRYPTWRITE].revents & POLLIN)) {
errno = 0;
cc = des_read(STDIN_FILENO,
buf, sizeof(buf));
if (cc <= 0) {
shutdown(pv2[0], SHUT_RDWR);
pfd[P_CRYPTWRITE].revents = 0;
} else
(void) write(pv2[0], buf, cc);
}
#endif
#endif
} while ((pfd[P_SOCKREAD].revents & POLLIN) ||
#ifdef CRYPT
#ifdef KERBEROS
(doencrypt && (pfd[P_CRYPTREAD].revents & POLLIN)) ||
#endif
#endif
(pfd[P_PIPEREAD].revents & POLLIN));
exit(0);
}
setsid();
(void) close(s);
(void) close(pv[0]);
#ifdef CRYPT
#ifdef KERBEROS
if (doencrypt) {
close(pv1[0]); close(pv2[0]);
dup2(pv1[1], 1);
dup2(pv2[1], 0);
close(pv1[1]);
close(pv2[1]);
}
#endif
#endif
dup2(pv[1], 2);
close(pv[1]);
} else
setsid();
if (*pwd->pw_shell == '\0')
pwd->pw_shell = _PATH_BSHELL;
environ = envinit;
if (setenv("HOME", pwd->pw_dir, 1) == -1 ||
setenv("SHELL", pwd->pw_shell, 1) == -1 ||
setenv("USER", pwd->pw_name, 1) == -1 ||
setenv("LOGNAME", pwd->pw_name, 1) == -1)
errx(1, "cannot setup environment");
if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETALL))
errx(1, "cannot set user context");
if (auth_approval(as, lc, pwd->pw_name, "rsh") <= 0)
errx(1, "approval failure");
auth_close(as);
login_close(lc);
cp = strrchr(pwd->pw_shell, '/');
if (cp)
cp++;
else
cp = pwd->pw_shell;
endpwent();
if (log_success || pwd->pw_uid == 0) {
#ifdef KERBEROS
if (use_kerberos)
syslog(LOG_INFO|LOG_AUTH,
"Kerberos shell from %s.%s@%s on %s as %s, cmd='%.80s'",
kdata->pname, kdata->pinst, kdata->prealm,
hostname, locuser, cmdbuf);
else
#endif
syslog(LOG_INFO|LOG_AUTH, "%s@%s as %s: cmd='%.80s'",
remuser, hostname, locuser, cmdbuf);
}
execl(pwd->pw_shell, cp, "-c", cmdbuf, (char *)NULL);
perror(pwd->pw_shell);
exit(1);
}
/*
* Report error to client. Note: can't be used until second socket has
* connected to client, or older clients will hang waiting for that
* connection first.
*/
void
error(const char *fmt, ...)
{
va_list ap;
int len;
char *bp, buf[BUFSIZ];
va_start(ap, fmt);
bp = buf;
if (sent_null == 0) {
*bp++ = 1;
len = 1;
} else
len = 0;
(void)vsnprintf(bp, sizeof(buf) - len, fmt, ap);
(void)write(STDERR_FILENO, buf, len + strlen(bp));
va_end(ap);
}
void
getstr(char *buf, int cnt, char *err)
{
char c;
do {
if (read(STDIN_FILENO, &c, 1) != 1)
exit(1);
*buf++ = c;
if (--cnt == 0) {
error("%s too long\n", err);
exit(1);
}
} while (c != 0);
}
/*
* 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(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(char *h)
{
char *p, *maybe = NULL;
int dots = 0;
for (p = h + strlen(h); p >= h; p--) {
if (*p == '.') {
if (++dots == 2)
return (p);
maybe = p;
}
}
return (maybe);
}
void
usage(void)
{
syslog(LOG_ERR, "usage: rshd [-%s]", OPTIONS);
exit(2);
}