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