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 } 121