contrib/tcp_wrappers/miscd.c

   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
  46 main(argc, argv)
  47 int     argc;
  48 char  **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 }