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).
10 * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
16 static char sccsid[] = "@(#) tcpd.c 1.10 96/02/11 17:01:32";
19 /* System libraries. */
21 #include <sys/types.h>
22 #include <sys/param.h>
24 #include <sys/socket.h>
25 #include <netinet/in.h>
30 #ifndef MAXPATHNAMELEN
31 #define MAXPATHNAMELEN BUFSIZ
35 #define STDIN_FILENO 0
40 #include "patchlevel.h"
43 int allow_severity = SEVERITY; /* run-time adjustable */
44 int deny_severity = LOG_WARNING; /* ditto */
50 struct request_info request;
51 char path[MAXPATHNAMELEN];
53 /* Attempt to prevent the creation of world-writable files. */
60 * If argv[0] is an absolute path name, ignore REAL_DAEMON_DIR, and strip
61 * argv[0] to its basename.
64 if (argv[0][0] == '/') {
65 strcpy(path, argv[0]);
66 argv[0] = strrchr(argv[0], '/') + 1;
68 sprintf(path, "%s/%s", REAL_DAEMON_DIR, argv[0]);
72 * Open a channel to the syslog daemon. Older versions of openlog()
73 * require only two arguments.
77 (void) openlog(argv[0], LOG_PID, FACILITY);
79 (void) openlog(argv[0], LOG_PID);
83 * Find out the endpoint addresses of this conversation. Host name
84 * lookups and double checks will be done on demand.
87 request_init(&request, RQ_DAEMON, argv[0], RQ_FILE, STDIN_FILENO, 0);
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.
97 if (STR_EQ(eval_hostname(request.client), paranoid))
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.
108 #ifdef KILL_IP_OPTIONS
109 fix_options(&request);
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.
119 if (!hosts_access(&request))
123 /* Report request and invoke the real daemon program. */
126 syslog(allow_severity, "connect from %s (%s)",
127 eval_client(&request), eval_hostaddr(request.client));
129 syslog(allow_severity, "connect from %s", eval_client(&request));
132 (void) execv(path, argv);
133 syslog(LOG_ERR, "error: cannot execute %s: %m", path);
134 clean_exit(&request);