1 /*
2 * Front end to the ULTRIX miscd service. The front end logs the remote host
3 * name and then invokes the real miscd daemon. Install as "/usr/etc/miscd",
4 * after renaming the real miscd daemon to the name defined with the
5 * REAL_MISCD macro.
6 *
7 * Connections and diagnostics are logged through syslog(3).
8 *
9 * The Ultrix miscd program implements (among others) the systat service, which
10 * pipes the output from who(1) to stdout. This information is potentially
11 * useful to systems crackers.
12 *
13 * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
14 */
15
16 #ifndef lint
17 static char sccsid[] = "@(#) miscd.c 1.10 96/02/11 17:01:30";
18 #endif
19
20 /* System libraries. */
21
22 #include <sys/types.h>
23 #include <sys/param.h>
24 #include <sys/stat.h>
25 #include <sys/socket.h>
26 #include <netinet/in.h>
27 #include <stdio.h>
28 #include <syslog.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
43 int allow_severity = SEVERITY; /* run-time adjustable */
44 int deny_severity = LOG_WARNING; /* ditto */
45
main(int argc,char ** argv)46 main(int argc, char **argv)
47 {
48 struct request_info request;
49 char path[MAXPATHNAMELEN];
50
51 /* Attempt to prevent the creation of world-writable files. */
52
53 #ifdef DAEMON_UMASK
54 umask(DAEMON_UMASK);
55 #endif
56
57 /*
58 * Open a channel to the syslog daemon. Older versions of openlog()
59 * require only two arguments.
60 */
61
62 #ifdef LOG_MAIL
63 (void) openlog(argv[0], LOG_PID, FACILITY);
64 #else
65 (void) openlog(argv[0], LOG_PID);
66 #endif
67
68 /*
69 * Find out the endpoint addresses of this conversation. Host name
70 * lookups and double checks will be done on demand.
71 */
72
73 request_init(&request, RQ_DAEMON, argv[0], RQ_FILE, STDIN_FILENO, 0);
74 fromhost(&request);
75
76 /*
77 * Optionally look up and double check the remote host name. Sites
78 * concerned with security may choose to refuse connections from hosts
79 * that pretend to have someone elses host name.
80 */
81
82 #ifdef PARANOID
83 if (STR_EQ(eval_hostname(request.client), paranoid))
84 refuse(&request);
85 #endif
86
87 /*
88 * The BSD rlogin and rsh daemons that came out after 4.3 BSD disallow
89 * socket options at the IP level. They do so for a good reason.
90 * Unfortunately, we cannot use this with SunOS 4.1.x because the
91 * getsockopt() system call can panic the system.
92 */
93
94 #ifdef KILL_IP_OPTIONS
95 fix_options(&request);
96 #endif
97
98 /*
99 * Check whether this host can access the service in argv[0]. The
100 * access-control code invokes optional shell commands as specified in
101 * the access-control tables.
102 */
103
104 #ifdef HOSTS_ACCESS
105 if (!hosts_access(&request))
106 refuse(&request);
107 #endif
108
109 /* Report request and invoke the real daemon program. */
110
111 syslog(allow_severity, "connect from %s", eval_client(&request));
112 sprintf(path, "%s/miscd", REAL_DAEMON_DIR);
113 closelog();
114 (void) execv(path, argv);
115 syslog(LOG_ERR, "error: cannot execute %s: %m", path);
116 clean_exit(&request);
117 /* NOTREACHED */
118 }
119