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