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Usenet 1994 October
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usenetsourcesnewsgroupsinfomagicoctober1994disk2.iso
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misc
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volume23
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log_tcp
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part01
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tcpd.c
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C/C++ Source or Header
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1991-10-19
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3KB
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93 lines
/*
* General front end for stream and datagram IP services. This program logs
* the remote host name and then invokes the real daemon. For example,
* install as /usr/etc/{tftpd,fingerd,telnetd,ftpd,rlogind,rshd,rexecd},
* after saving the real daemons in the directory "/usr/etc/...". This
* arrangement requires that the network daemons are started by inetd or
* something similar. Connections and diagnostics are logged through
* syslog(3).
*
* Compile with -DHOSTS_ACCESS in order to enable access control. See the
* hosts_access(5) manual page for details.
*
* Compile with -DPARANOID if service should be refused to hosts that pretend
* to have someone elses host name. This gives some protection against rsh
* and rlogin attacks that involve compromised domain name servers.
*
* Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
*/
#ifndef lint
static char sccsid[] = "@(#) tcpd.c 1.2 91/10/02 23:01:44";
#endif
/* System libraries. */
#include <sys/types.h>
#include <sys/param.h>
#include <stdio.h>
#include <syslog.h>
#ifndef MAXPATHNAMELEN
#define MAXPATHNAMELEN BUFSIZ
#endif
/* Local stuff. */
#include "log_tcp.h"
/* The following specifies where the vendor-provided daemons should go. */
#define REAL_DAEMON_DIR "/usr/etc/..."
main(argc, argv)
int argc;
char **argv;
{
struct from_host from;
int from_stat;
char path[MAXPATHNAMELEN];
/*
* Open a channel to the syslog daemon. Older versions of openlog()
* require only two arguments.
*/
#ifdef LOG_MAIL
(void) openlog(argv[0], LOG_PID, FACILITY);
#else
(void) openlog(argv[0], LOG_PID);
#endif
/*
* Find out and verify the remote host name. Sites concerned with
* security may choose to refuse connections from hosts that pretend to
* have someone elses host name.
*/
from_stat = fromhost(&from);
#ifdef PARANOID
if (from_stat == -1)
refuse(&from);
#endif
/*
* Check whether this host can access the service in argv[0]. The
* access-control code invokes optional shell commands as specified in
* the access-control tables.
*/
#ifdef HOSTS_ACCESS
if (!hosts_access(argv[0], from.source))
refuse(&from);
#endif
/* Report remote host name and invoke the real daemon program. */
syslog(LOG_INFO, "connect from %s", from.source);
sprintf(path, "%s/%s", REAL_DAEMON_DIR, argv[0]);
(void) execv(path, argv);
syslog(LOG_ERR, "%s: %m", path);
return (1);
}