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 * $FreeBSD$ 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 main(argc, argv) 48 int argc; 49 char **argv; 50 { 51 struct request_info request; 52 char path[MAXPATHNAMELEN]; 53 54 /* Attempt to prevent the creation of world-writable files. */ 55 56 #ifdef DAEMON_UMASK 57 umask(DAEMON_UMASK); 58 #endif 59 60 /* 61 * If argv[0] is an absolute path name, ignore REAL_DAEMON_DIR, and strip 62 * argv[0] to its basename. 63 */ 64 65 if (argv[0][0] == '/') { 66 strlcpy(path, argv[0], sizeof(path)); 67 argv[0] = strrchr(argv[0], '/') + 1; 68 } else { 69 snprintf(path, sizeof(path), "%s/%s", REAL_DAEMON_DIR, argv[0]); 70 } 71 72 /* 73 * Open a channel to the syslog daemon. Older versions of openlog() 74 * require only two arguments. 75 */ 76 77 #ifdef LOG_MAIL 78 (void) openlog(argv[0], LOG_PID, FACILITY); 79 #else 80 (void) openlog(argv[0], LOG_PID); 81 #endif 82 83 /* 84 * Find out the endpoint addresses of this conversation. Host name 85 * lookups and double checks will be done on demand. 86 */ 87 88 request_init(&request, RQ_DAEMON, argv[0], RQ_FILE, STDIN_FILENO, 0); 89 fromhost(&request); 90 91 /* 92 * Optionally look up and double check the remote host name. Sites 93 * concerned with security may choose to refuse connections from hosts 94 * that pretend to have someone elses host name. 95 */ 96 97 #ifdef PARANOID 98 if (STR_EQ(eval_hostname(request.client), paranoid)) 99 refuse(&request); 100 #endif 101 102 /* 103 * The BSD rlogin and rsh daemons that came out after 4.3 BSD disallow 104 * socket options at the IP level. They do so for a good reason. 105 * Unfortunately, we cannot use this with SunOS 4.1.x because the 106 * getsockopt() system call can panic the system. 107 */ 108 109 #ifdef KILL_IP_OPTIONS 110 fix_options(&request); 111 #endif 112 113 /* 114 * Check whether this host can access the service in argv[0]. The 115 * access-control code invokes optional shell commands as specified in 116 * the access-control tables. 117 */ 118 119 #ifdef HOSTS_ACCESS 120 if (!hosts_access(&request)) 121 refuse(&request); 122 #endif 123 124 /* Report request and invoke the real daemon program. */ 125 126 #ifdef INET6 127 syslog(allow_severity, "connect from %s (%s)", 128 eval_client(&request), eval_hostaddr(request.client)); 129 #else 130 syslog(allow_severity, "connect from %s", eval_client(&request)); 131 #endif 132 closelog(); 133 (void) execv(path, argv); 134 syslog(LOG_ERR, "error: cannot execute %s: %m", path); 135 clean_exit(&request); 136 /* NOTREACHED */ 137 } 138