1 /* 2 * General front end for stream and datagram IP services. This program logs 3 * the remote host name and then invokes the real daemon. For example, 4 * install as /usr/etc/{tftpd,fingerd,telnetd,ftpd,rlogind,rshd,rexecd}, 5 * after saving the real daemons in the directory specified with the 6 * REAL_DAEMON_DIR macro. This arrangement requires that the network daemons 7 * are started by inetd or something similar. Connections and diagnostics 8 * are logged through syslog(3). 9 * 10 * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands. 11 * 12 * $FreeBSD: src/contrib/tcp_wrappers/tcpd.c,v 1.2 2000/02/03 10:26:59 shin Exp $ 13 */ 14 15 #ifndef lint 16 static char sccsid[] = "@(#) tcpd.c 1.10 96/02/11 17:01:32"; 17 #endif 18 19 /* System libraries. */ 20 21 #include <sys/types.h> 22 #include <sys/param.h> 23 #include <sys/stat.h> 24 #include <sys/socket.h> 25 #include <netinet/in.h> 26 #include <stdio.h> 27 #include <syslog.h> 28 #include <string.h> 29 #include <unistd.h> 30 31 #ifndef MAXPATHNAMELEN 32 #define MAXPATHNAMELEN BUFSIZ 33 #endif 34 35 #ifndef STDIN_FILENO 36 #define STDIN_FILENO 0 37 #endif 38 39 /* Local stuff. */ 40 41 #include "patchlevel.h" 42 #include "tcpd.h" 43 44 int allow_severity = SEVERITY; /* run-time adjustable */ 45 int deny_severity = LOG_WARNING; /* ditto */ 46 47 int 48 main(argc, argv) 49 int argc; 50 char **argv; 51 { 52 struct request_info request; 53 char path[MAXPATHNAMELEN]; 54 55 /* Attempt to prevent the creation of world-writable files. */ 56 57 #ifdef DAEMON_UMASK 58 umask(DAEMON_UMASK); 59 #endif 60 61 /* 62 * If argv[0] is an absolute path name, ignore REAL_DAEMON_DIR, and strip 63 * argv[0] to its basename. 64 */ 65 66 if (argv[0][0] == '/') { 67 strcpy(path, argv[0]); 68 argv[0] = strrchr(argv[0], '/') + 1; 69 } else { 70 sprintf(path, "%s/%s", REAL_DAEMON_DIR, argv[0]); 71 } 72 73 /* 74 * Open a channel to the syslog daemon. Older versions of openlog() 75 * require only two arguments. 76 */ 77 78 #ifdef LOG_MAIL 79 (void) openlog(argv[0], LOG_PID, FACILITY); 80 #else 81 (void) openlog(argv[0], LOG_PID); 82 #endif 83 84 /* 85 * Find out the endpoint addresses of this conversation. Host name 86 * lookups and double checks will be done on demand. 87 */ 88 89 request_init(&request, RQ_DAEMON, argv[0], RQ_FILE, STDIN_FILENO, 0); 90 fromhost(&request); 91 92 /* 93 * Optionally look up and double check the remote host name. Sites 94 * concerned with security may choose to refuse connections from hosts 95 * that pretend to have someone elses host name. 96 */ 97 98 #ifdef PARANOID 99 if (STR_EQ(eval_hostname(request.client), paranoid)) 100 refuse(&request); 101 #endif 102 103 /* 104 * The BSD rlogin and rsh daemons that came out after 4.3 BSD disallow 105 * socket options at the IP level. They do so for a good reason. 106 * Unfortunately, we cannot use this with SunOS 4.1.x because the 107 * getsockopt() system call can panic the system. 108 */ 109 110 #ifdef KILL_IP_OPTIONS 111 fix_options(&request); 112 #endif 113 114 /* 115 * Check whether this host can access the service in argv[0]. The 116 * access-control code invokes optional shell commands as specified in 117 * the access-control tables. 118 */ 119 120 #ifdef HOSTS_ACCESS 121 if (!hosts_access(&request)) 122 refuse(&request); 123 #endif 124 125 /* Report request and invoke the real daemon program. */ 126 127 #ifdef INET6 128 syslog(allow_severity, "connect from %s (%s)", 129 eval_client(&request), eval_hostaddr(request.client)); 130 #else 131 syslog(allow_severity, "connect from %s", eval_client(&request)); 132 #endif 133 closelog(); 134 (void) execv(path, argv); 135 syslog(LOG_ERR, "error: cannot execute %s: %m", path); 136 clean_exit(&request); 137 /* NOTREACHED */ 138 } 139