1 /* $NetBSD: eval.c,v 1.7 2012/03/21 10:10:37 matt Exp $ */ 2 3 /* 4 * Routines for controlled evaluation of host names, user names, and so on. 5 * They are, in fact, wrappers around the functions that are specific for 6 * the sockets or TLI programming interfaces. The request_info and host_info 7 * structures are used for result cacheing. 8 * 9 * These routines allows us to postpone expensive operations until their 10 * results are really needed. Examples are hostname lookups and double 11 * checks, or username lookups. Information that cannot be retrieved is 12 * given the value "unknown" ("paranoid" in case of hostname problems). 13 * 14 * When ALWAYS_HOSTNAME is off, hostname lookup is done only when required by 15 * tcpd paranoid mode, by access control patterns, or by %letter expansions. 16 * 17 * When ALWAYS_RFC931 mode is off, user lookup is done only when required by 18 * access control patterns or %letter expansions. 19 * 20 * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands. 21 */ 22 23 #include <sys/cdefs.h> 24 #ifndef lint 25 #if 0 26 static char sccsid[] = "@(#) eval.c 1.3 95/01/30 19:51:45"; 27 #else 28 __RCSID("$NetBSD: eval.c,v 1.7 2012/03/21 10:10:37 matt Exp $"); 29 #endif 30 #endif 31 32 /* System libraries. */ 33 34 #include <stdio.h> 35 #include <string.h> 36 37 /* Local stuff. */ 38 39 #include "tcpd.h" 40 41 /* 42 * When a string has the value STRING_UNKNOWN, it means: don't bother, I 43 * tried to look up the data but it was unavailable for some reason. When a 44 * host name has the value STRING_PARANOID it means there was a name/address 45 * conflict. 46 */ 47 char unknown[] = STRING_UNKNOWN; 48 char paranoid[] = STRING_PARANOID; 49 50 /* eval_user - look up user name */ 51 52 char * 53 eval_user(struct request_info *request) 54 { 55 if (request->user[0] == 0) { 56 (void)strlcpy(request->user, unknown, sizeof(request->user)); 57 if (request->sink == 0 && request->client->sin && request->server->sin) 58 rfc931(request->client->sin, request->server->sin, request->user); 59 } 60 return (request->user); 61 } 62 63 /* eval_hostaddr - look up printable address */ 64 65 char * 66 eval_hostaddr(struct host_info *host) 67 { 68 if (host->addr[0] == 0) { 69 (void)strlcpy(host->addr, unknown, sizeof(host->addr)); 70 if (host->request->hostaddr != 0) 71 host->request->hostaddr(host); 72 } 73 return (host->addr); 74 } 75 76 /* eval_hostname - look up host name */ 77 78 char * 79 eval_hostname(struct host_info *host) 80 { 81 if (host->name[0] == 0) { 82 (void)strlcpy(host->name, unknown, sizeof(host->name)); 83 if (host->request->hostname != 0) 84 host->request->hostname(host); 85 } 86 return (host->name); 87 } 88 89 /* eval_hostinfo - return string with host name (preferred) or address */ 90 91 char * 92 eval_hostinfo(struct host_info *host) 93 { 94 char *hostname; 95 96 #ifndef ALWAYS_HOSTNAME /* no implicit host lookups */ 97 if (host->name[0] == 0) 98 return (eval_hostaddr(host)); 99 #endif 100 hostname = eval_hostname(host); 101 if (HOSTNAME_KNOWN(hostname)) { 102 return (host->name); 103 } else { 104 return (eval_hostaddr(host)); 105 } 106 } 107 108 /* eval_client - return string with as much about the client as we know */ 109 110 char * 111 eval_client(struct request_info *request) 112 { 113 static char both[2 * STRING_LENGTH]; 114 char *hostinfo = eval_hostinfo(request->client); 115 116 #ifndef ALWAYS_RFC931 /* no implicit user lookups */ 117 if (request->user[0] == 0) 118 return (hostinfo); 119 #endif 120 if (STR_NE(eval_user(request), unknown)) { 121 (void)snprintf(both, sizeof both, "%s@%s", request->user, hostinfo); 122 return (both); 123 } else { 124 return (hostinfo); 125 } 126 } 127 128 /* eval_server - return string with as much about the server as we know */ 129 130 char * 131 eval_server(struct request_info *request) 132 { 133 static char both[2 * STRING_LENGTH]; 134 char *host = eval_hostinfo(request->server); 135 char *daemon = eval_daemon(request); 136 137 if (STR_NE(host, unknown)) { 138 (void)snprintf(both, sizeof both, "%s@%s", daemon, host); 139 return (both); 140 } else { 141 return (daemon); 142 } 143 } 144