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/*
* 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 specified with the
* REAL_DAEMON_DIR macro. This arrangement requires that the network daemons
* are started by inetd or something similar. Connections and diagnostics
* are logged through syslog(3).
*
* Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
*/
#ifndef lint
static char sccsid[] = "@(#) tcpd.c 1.10 96/02/11 17:01:32";
#endif
/* System libraries. */
#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdio.h>
#include <syslog.h>
#include <string.h>
#ifndef MAXPATHNAMELEN
#define MAXPATHNAMELEN BUFSIZ
#endif
#ifndef STDIN_FILENO
#define STDIN_FILENO 0
#endif
/* Local stuff. */
#include "patchlevel.h"
#include "tcpd.h"
int allow_severity = SEVERITY; /* run-time adjustable */
int deny_severity = LOG_WARNING; /* ditto */
main(argc, argv)
int argc;
char **argv;
{
struct request_info request;
char path[MAXPATHNAMELEN];
/* Attempt to prevent the creation of world-writable files. */
#ifdef DAEMON_UMASK
umask(DAEMON_UMASK);
#endif
/*
* If argv[0] is an absolute path name, ignore REAL_DAEMON_DIR, and strip
* argv[0] to its basename.
*/
if (argv[0][0] == '/') {
strcpy(path, argv[0]);
argv[0] = strrchr(argv[0], '/') + 1;
} else {
sprintf(path, "%s/%s", REAL_DAEMON_DIR, argv[0]);
}
/*
* 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 the endpoint addresses of this conversation. Host name
* lookups and double checks will be done on demand.
*/
request_init(&request, RQ_DAEMON, argv[0], RQ_FILE, STDIN_FILENO, 0);
fromhost(&request);
/*
* Optionally look up and double check the remote host name. Sites
* concerned with security may choose to refuse connections from hosts
* that pretend to have someone elses host name.
*/
#ifdef PARANOID
if (STR_EQ(eval_hostname(request.client), paranoid))
refuse(&request);
#endif
/*
* The BSD rlogin and rsh daemons that came out after 4.3 BSD disallow
* socket options at the IP level. They do so for a good reason.
* Unfortunately, we cannot use this with SunOS 4.1.x because the
* getsockopt() system call can panic the system.
*/
#ifdef KILL_IP_OPTIONS
fix_options(&request);
#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(&request))
refuse(&request);
#endif
/* Report request and invoke the real daemon program. */
syslog(allow_severity, "connect from %s", eval_client(&request));
closelog();
(void) execv(path, argv);
syslog(LOG_ERR, "error: cannot execute %s: %m", path);
clean_exit(&request);
/* NOTREACHED */
}
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