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
17static 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
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     * Open a channel to the syslog daemon. Older versions of openlog()
61     * require only two arguments.
62     */
63
64#ifdef LOG_MAIL
65    (void) openlog(argv[0], LOG_PID, FACILITY);
66#else
67    (void) openlog(argv[0], LOG_PID);
68#endif
69
70    /*
71     * Find out the endpoint addresses of this conversation. Host name
72     * lookups and double checks will be done on demand.
73     */
74
75    request_init(&request, RQ_DAEMON, argv[0], RQ_FILE, STDIN_FILENO, 0);
76    fromhost(&request);
77
78    /*
79     * Optionally look up and double check the remote host name. Sites
80     * concerned with security may choose to refuse connections from hosts
81     * that pretend to have someone elses host name.
82     */
83
84#ifdef PARANOID
85    if (STR_EQ(eval_hostname(request.client), paranoid))
86	refuse(&request);
87#endif
88
89    /*
90     * The BSD rlogin and rsh daemons that came out after 4.3 BSD disallow
91     * socket options at the IP level. They do so for a good reason.
92     * Unfortunately, we cannot use this with SunOS 4.1.x because the
93     * getsockopt() system call can panic the system.
94     */
95
96#ifdef KILL_IP_OPTIONS
97    fix_options(&request);
98#endif
99
100    /*
101     * Check whether this host can access the service in argv[0]. The
102     * access-control code invokes optional shell commands as specified in
103     * the access-control tables.
104     */
105
106#ifdef HOSTS_ACCESS
107    if (!hosts_access(&request))
108	refuse(&request);
109#endif
110
111    /* Report request and invoke the real daemon program. */
112
113    syslog(allow_severity, "connect from %s", eval_client(&request));
114    sprintf(path, "%s/miscd", REAL_DAEMON_DIR);
115    closelog();
116    (void) execv(path, argv);
117    syslog(LOG_ERR, "error: cannot execute %s: %m", path);
118    clean_exit(&request);
119    /* NOTREACHED */
120}
121