1 /*
2 * General front end for stream and datagram IP services. This program logs
3 * the remote host name and then invokes the real daemon. For example,
4 * install as /usr/etc/{tftpd,fingerd,telnetd,ftpd,rlogind,rshd,rexecd},
5 * after saving the real daemons in the directory specified with the
6 * REAL_DAEMON_DIR macro. This arrangement requires that the network daemons
7 * are started by inetd or something similar. Connections and diagnostics
8 * are logged through syslog(3).
9 *
10 * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
11 *
12 * $FreeBSD: head/contrib/tcp_wrappers/tcpd.c 56977 2000-02-03 10:27:03Z shin $
13 */
14
15#ifndef lint
16static char sccsid[] = "@(#) tcpd.c 1.10 96/02/11 17:01:32";
17#endif
18
19/* System libraries. */
20
21#include <sys/types.h>
22#include <sys/param.h>
23#include <sys/stat.h>
24#include <sys/socket.h>
25#include <netinet/in.h>
26#include <stdio.h>
27#include <syslog.h>
28#include <string.h>
29
30#ifndef MAXPATHNAMELEN
31#define MAXPATHNAMELEN BUFSIZ
32#endif
33
34#ifndef STDIN_FILENO
35#define STDIN_FILENO 0
36#endif
37
38/* Local stuff. */
39
40#include "patchlevel.h"
41#include "tcpd.h"
42
43int allow_severity = SEVERITY; /* run-time adjustable */
44int deny_severity = LOG_WARNING; /* ditto */
45
46main(argc, argv)
47int argc;
48char **argv;
49{
50 struct request_info request;
51 char path[MAXPATHNAMELEN];
52
53 /* Attempt to prevent the creation of world-writable files. */
54
55#ifdef DAEMON_UMASK
56 umask(DAEMON_UMASK);
57#endif
58
59 /*
60 * If argv[0] is an absolute path name, ignore REAL_DAEMON_DIR, and strip
61 * argv[0] to its basename.
62 */
63
64 if (argv[0][0] == '/') {
65 strcpy(path, argv[0]);
66 argv[0] = strrchr(argv[0], '/') + 1;
67 } else {
68 sprintf(path, "%s/%s", REAL_DAEMON_DIR, argv[0]);
69 }
70
71 /*
72 * Open a channel to the syslog daemon. Older versions of openlog()
73 * require only two arguments.
74 */
75
76#ifdef LOG_MAIL
77 (void) openlog(argv[0], LOG_PID, FACILITY);
78#else
79 (void) openlog(argv[0], LOG_PID);
80#endif
81
82 /*
83 * Find out the endpoint addresses of this conversation. Host name
84 * lookups and double checks will be done on demand.
85 */
86
87 request_init(&request, RQ_DAEMON, argv[0], RQ_FILE, STDIN_FILENO, 0);
88 fromhost(&request);
89
90 /*
91 * Optionally look up and double check the remote host name. Sites
92 * concerned with security may choose to refuse connections from hosts
93 * that pretend to have someone elses host name.
94 */
95
96#ifdef PARANOID
97 if (STR_EQ(eval_hostname(request.client), paranoid))
98 refuse(&request);
99#endif
100
101 /*
102 * The BSD rlogin and rsh daemons that came out after 4.3 BSD disallow
103 * socket options at the IP level. They do so for a good reason.
104 * Unfortunately, we cannot use this with SunOS 4.1.x because the
105 * getsockopt() system call can panic the system.
106 */
107
108#ifdef KILL_IP_OPTIONS
109 fix_options(&request);
110#endif
111
112 /*
113 * Check whether this host can access the service in argv[0]. The
114 * access-control code invokes optional shell commands as specified in
115 * the access-control tables.
116 */
117
118#ifdef HOSTS_ACCESS
119 if (!hosts_access(&request))
120 refuse(&request);
121#endif
122
123 /* Report request and invoke the real daemon program. */
124
125#ifdef INET6
126 syslog(allow_severity, "connect from %s (%s)",
127 eval_client(&request), eval_hostaddr(request.client));
128#else
129 syslog(allow_severity, "connect from %s", eval_client(&request));
130#endif
131 closelog();
132 (void) execv(path, argv);
133 syslog(LOG_ERR, "error: cannot execute %s: %m", path);
134 clean_exit(&request);
135 /* NOTREACHED */
136}