NetBSD/lib/libc/net/rcmd.c

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/* $NetBSD: rcmd.c,v 1.14 1996/05/28 02:07:44 mrg Exp $ */
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/*
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* Copyright (c) 1983, 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)rcmd.c 8.3 (Berkeley) 3/26/94";
#else
static char *rcsid = "$NetBSD: rcmd.c,v 1.14 1996/05/28 02:07:44 mrg Exp $";
#endif
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#endif /* LIBC_SCCS and not lint */
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/stat.h>
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#include <netinet/in.h>
#include <arpa/inet.h>
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#include <signal.h>
#include <fcntl.h>
#include <netdb.h>
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#include <unistd.h>
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#include <pwd.h>
#include <errno.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <syslog.h>
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int __ivaliduser __P((FILE *, u_int32_t, const char *, const char *));
static int __icheckhost __P((u_int32_t, const char *));
static char *__gethostloop __P((u_int32_t));
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int
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rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
char **ahost;
u_short rport;
const char *locuser, *remuser, *cmd;
int *fd2p;
{
struct hostent *hp;
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struct sockaddr_in sin, from;
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fd_set reads;
int oldmask;
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pid_t pid;
int s, lport, timo;
char c;
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pid = getpid();
hp = gethostbyname(*ahost);
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if (hp == NULL) {
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herror(*ahost);
return (-1);
}
*ahost = hp->h_name;
oldmask = sigblock(sigmask(SIGURG));
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for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
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s = rresvport(&lport);
if (s < 0) {
if (errno == EAGAIN)
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(void)fprintf(stderr,
"rcmd: socket: All ports in use\n");
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else
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(void)fprintf(stderr, "rcmd: socket: %s\n",
strerror(errno));
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sigsetmask(oldmask);
return (-1);
}
fcntl(s, F_SETOWN, pid);
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sin.sin_len = sizeof(struct sockaddr_in);
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sin.sin_family = hp->h_addrtype;
sin.sin_port = rport;
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bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length);
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if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
break;
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(void)close(s);
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if (errno == EADDRINUSE) {
lport--;
continue;
}
if (errno == ECONNREFUSED && timo <= 16) {
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(void)sleep(timo);
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timo *= 2;
continue;
}
if (hp->h_addr_list[1] != NULL) {
int oerrno = errno;
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(void)fprintf(stderr, "connect to address %s: ",
inet_ntoa(sin.sin_addr));
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errno = oerrno;
perror(0);
hp->h_addr_list++;
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bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length);
(void)fprintf(stderr, "Trying %s...\n",
inet_ntoa(sin.sin_addr));
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continue;
}
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(void)fprintf(stderr, "%s: %s\n", hp->h_name, strerror(errno));
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sigsetmask(oldmask);
return (-1);
}
lport--;
if (fd2p == 0) {
write(s, "", 1);
lport = 0;
} else {
char num[8];
int s2 = rresvport(&lport), s3;
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int len = sizeof(from);
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if (s2 < 0)
goto bad;
listen(s2, 1);
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(void)snprintf(num, sizeof(num), "%d", lport);
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if (write(s, num, strlen(num)+1) != strlen(num)+1) {
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(void)fprintf(stderr,
"rcmd: write (setting up stderr): %s\n",
strerror(errno));
(void)close(s2);
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goto bad;
}
FD_ZERO(&reads);
FD_SET(s, &reads);
FD_SET(s2, &reads);
errno = 0;
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if (select(MAX(s, s2) + 1, &reads, 0, 0, 0) < 1 ||
!FD_ISSET(s2, &reads)) {
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if (errno != 0)
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(void)fprintf(stderr,
"rcmd: select (setting up stderr): %s\n",
strerror(errno));
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else
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(void)fprintf(stderr,
"select: protocol failure in circuit setup\n");
(void)close(s2);
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goto bad;
}
s3 = accept(s2, (struct sockaddr *)&from, &len);
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(void)close(s2);
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if (s3 < 0) {
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(void)fprintf(stderr,
"rcmd: accept: %s\n", strerror(errno));
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lport = 0;
goto bad;
}
*fd2p = s3;
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from.sin_port = ntohs(from.sin_port);
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if (from.sin_family != AF_INET ||
from.sin_port >= IPPORT_RESERVED ||
from.sin_port < IPPORT_RESERVED / 2) {
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(void)fprintf(stderr,
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"socket: protocol failure in circuit setup.\n");
goto bad2;
}
}
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(void)write(s, locuser, strlen(locuser)+1);
(void)write(s, remuser, strlen(remuser)+1);
(void)write(s, cmd, strlen(cmd)+1);
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if (read(s, &c, 1) != 1) {
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(void)fprintf(stderr,
"rcmd: %s: %s\n", *ahost, strerror(errno));
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goto bad2;
}
if (c != 0) {
while (read(s, &c, 1) == 1) {
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(void)write(STDERR_FILENO, &c, 1);
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if (c == '\n')
break;
}
goto bad2;
}
sigsetmask(oldmask);
return (s);
bad2:
if (lport)
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(void)close(*fd2p);
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bad:
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(void)close(s);
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sigsetmask(oldmask);
return (-1);
}
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int
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rresvport(alport)
int *alport;
{
struct sockaddr_in sin;
int s;
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sin.sin_len = sizeof(struct sockaddr_in);
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sin.sin_family = AF_INET;
sin.sin_addr.s_addr = INADDR_ANY;
s = socket(AF_INET, SOCK_STREAM, 0);
if (s < 0)
return (-1);
for (;;) {
sin.sin_port = htons((u_short)*alport);
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if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
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return (s);
if (errno != EADDRINUSE) {
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(void)close(s);
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return (-1);
}
(*alport)--;
if (*alport == IPPORT_RESERVED/2) {
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(void)close(s);
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errno = EAGAIN; /* close */
return (-1);
}
}
}
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int __check_rhosts_file = 1;
char *__rcmd_errstr;
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int
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ruserok(rhost, superuser, ruser, luser)
const char *rhost, *ruser, *luser;
int superuser;
{
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struct hostent *hp;
char **ap;
int i;
#define MAXADDRS 35
u_int32_t addrs[MAXADDRS + 1];
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if ((hp = gethostbyname(rhost)) == NULL)
return (-1);
for (i = 0, ap = hp->h_addr_list; *ap && i < MAXADDRS; ++ap, ++i)
bcopy(*ap, &addrs[i], sizeof(addrs[i]));
addrs[i] = 0;
for (i = 0; i < MAXADDRS && addrs[i]; i++)
if (iruserok(addrs[i], superuser, ruser, luser) == 0)
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return (0);
return (-1);
}
/*
* New .rhosts strategy: We are passed an ip address. We spin through
* hosts.equiv and .rhosts looking for a match. When the .rhosts only
* has ip addresses, we don't have to trust a nameserver. When it
* contains hostnames, we spin through the list of addresses the nameserver
* gives us and look for a match.
*
* Returns 0 if ok, -1 if not ok.
*/
int
iruserok(raddr, superuser, ruser, luser)
u_int32_t raddr;
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int superuser;
const char *ruser, *luser;
{
register char *cp;
struct stat sbuf;
struct passwd *pwd;
FILE *hostf;
uid_t uid;
int first;
char pbuf[MAXPATHLEN];
first = 1;
hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
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again:
if (hostf) {
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if (__ivaliduser(hostf, raddr, luser, ruser) == 0) {
(void)fclose(hostf);
return (0);
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}
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(void)fclose(hostf);
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}
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if (first == 1 && (__check_rhosts_file || superuser)) {
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first = 0;
if ((pwd = getpwnam(luser)) == NULL)
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return (-1);
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(void)strcpy(pbuf, pwd->pw_dir);
(void)strcat(pbuf, "/.rhosts");
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/*
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* Change effective uid while opening .rhosts. If root and
* reading an NFS mounted file system, can't read files that
* are protected read/write owner only.
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*/
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uid = geteuid();
(void)seteuid(pwd->pw_uid);
hostf = fopen(pbuf, "r");
(void)seteuid(uid);
if (hostf == NULL)
return (-1);
/*
* If not a regular file, or is owned by someone other than
* user or root or if writeable by anyone but the owner, quit.
*/
cp = NULL;
if (lstat(pbuf, &sbuf) < 0)
cp = ".rhosts lstat failed";
else if (!S_ISREG(sbuf.st_mode))
cp = ".rhosts not regular file";
else if (fstat(fileno(hostf), &sbuf) < 0)
cp = ".rhosts fstat failed";
else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
cp = "bad .rhosts owner";
else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
cp = ".rhosts writeable by other than owner";
/* If there were any problems, quit. */
if (cp) {
__rcmd_errstr = cp;
(void)fclose(hostf);
return (-1);
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}
goto again;
}
return (-1);
}
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/*
* XXX
* Don't make static, used by lpd(8).
*
* Returns 0 if ok, -1 if not ok.
*/
int
__ivaliduser(hostf, raddr, luser, ruser)
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FILE *hostf;
u_int32_t raddr;
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const char *luser, *ruser;
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{
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register char *user, *p;
int ch;
char buf[MAXHOSTNAMELEN + 128]; /* host + login */
const char *auser, *ahost;
int hostok, userok;
char *rhost = NULL;
int firsttime = 1;
char domain[MAXHOSTNAMELEN];
getdomainname(domain, sizeof(domain));
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while (fgets(buf, sizeof(buf), hostf)) {
p = buf;
/* Skip lines that are too long. */
if (strchr(p, '\n') == NULL) {
while ((ch = getc(hostf)) != '\n' && ch != EOF)
;
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continue;
}
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while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
*p = isupper(*p) ? tolower(*p) : *p;
p++;
}
if (*p == ' ' || *p == '\t') {
*p++ = '\0';
while (*p == ' ' || *p == '\t')
p++;
user = p;
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while (*p != '\n' && *p != ' ' &&
*p != '\t' && *p != '\0')
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p++;
} else
user = p;
*p = '\0';
if (p == buf)
continue;
auser = *user ? user : luser;
ahost = buf;
if (ahost[0] == '+')
switch (ahost[1]) {
case '\0':
hostok = 1;
break;
case '@':
if (firsttime) {
rhost = __gethostloop(raddr);
firsttime = 0;
}
if (rhost)
hostok = innetgr(&ahost[2], rhost,
NULL, domain);
else
hostok = 0;
break;
default:
hostok = __icheckhost(raddr, &ahost[1]);
break;
}
else if (ahost[0] == '-')
switch (ahost[1]) {
case '\0':
hostok = -1;
break;
case '@':
if (firsttime) {
rhost = __gethostloop(raddr);
firsttime = 0;
}
if (rhost)
hostok = -innetgr(&ahost[2], rhost,
NULL, domain);
else
hostok = 0;
break;
default:
hostok = -__icheckhost(raddr, &ahost[1]);
break;
}
else
hostok = __icheckhost(raddr, ahost);
if (auser[0] == '+')
switch (auser[1]) {
case '\0':
userok = 1;
break;
case '@':
userok = innetgr(&auser[2], NULL, ruser,
domain);
break;
default:
userok = strcmp(ruser, &auser[1]) == 0;
break;
}
else if (auser[0] == '-')
switch (auser[1]) {
case '\0':
userok = -1;
break;
case '@':
userok = -innetgr(&auser[2], NULL, ruser,
domain);
break;
default:
userok = -(strcmp(ruser, &auser[1]) == 0);
break;
}
else
userok = strcmp(ruser, auser) == 0;
/* Check if one component did not match */
if (hostok == 0 || userok == 0)
continue;
/* Check if we got a forbidden pair */
if (userok == -1 || hostok == -1)
return -1;
/* Check if we got a valid pair */
if (hostok == 1 && userok == 1)
return 0;
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}
return -1;
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}
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/*
* Returns "true" if match, 0 if no match.
*/
static int
__icheckhost(raddr, lhost)
u_int32_t raddr;
const char *lhost;
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{
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register struct hostent *hp;
register u_int32_t laddr;
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register char **pp;
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/* Try for raw ip address first. */
if (isdigit(*lhost) && (int32_t)(laddr = inet_addr(lhost)) != -1)
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return (raddr == laddr);
/* Better be a hostname. */
if ((hp = gethostbyname(lhost)) == NULL)
return (0);
/* Spin through ip addresses. */
for (pp = hp->h_addr_list; *pp; ++pp)
if (!bcmp(&raddr, *pp, sizeof(u_int32_t)))
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return (1);
/* No match. */
return (0);
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}
/*
* Return the hostname associated with the supplied address.
* Do a reverse lookup as well for security. If a loop cannot
* be found, pack the result of inet_ntoa() into the string.
*/
static char *
__gethostloop(raddr)
u_int32_t raddr;
{
static char remotehost[MAXHOSTNAMELEN];
struct hostent *hp;
struct in_addr in;
hp = gethostbyaddr((char *) &raddr, sizeof(raddr), AF_INET);
if (hp == NULL)
return (NULL);
/*
* Look up the name and check that the supplied
* address is in the list
*/
strncpy(remotehost, hp->h_name, sizeof(remotehost) - 1);
remotehost[sizeof(remotehost) - 1] = '\0';
hp = gethostbyname(remotehost);
if (hp == NULL)
return (NULL);
for (; hp->h_addr_list[0] != NULL; hp->h_addr_list++)
if (!bcmp(hp->h_addr_list[0], (caddr_t)&raddr, sizeof(raddr)))
return (remotehost);
/*
* either the DNS adminstrator has made a configuration
* mistake, or someone has attempted to spoof us
*/
in.s_addr = raddr;
syslog(LOG_NOTICE, "rcmd: address %s not listed for host %s",
inet_ntoa(in), hp->h_name);
return (NULL);
}