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(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