1 /*
2 * Copyright 2001 Sun Microsystems, Inc. All rights reserved.
3 * Use is subject to license terms.
4 */
5
6 /*
7 * Routines for controlled evaluation of host names, user names, and so on.
8 * They are, in fact, wrappers around the functions that are specific for
9 * the sockets or TLI programming interfaces. The request_info and host_info
10 * structures are used for result cacheing.
11 *
12 * These routines allows us to postpone expensive operations until their
13 * results are really needed. Examples are hostname lookups and double
14 * checks, or username lookups. Information that cannot be retrieved is
15 * given the value "unknown" ("paranoid" in case of hostname problems).
16 *
17 * When ALWAYS_HOSTNAME is off, hostname lookup is done only when required by
18 * tcpd paranoid mode, by access control patterns, or by %letter expansions.
19 *
20 * When ALWAYS_RFC931 mode is off, user lookup is done only when required by
21 * access control patterns or %letter expansions.
22 *
23 * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
24 */
25
26 #ifndef lint
27 static char sccsid[] = "@(#) eval.c 1.3 95/01/30 19:51:45";
28 #endif
29
30 /* System libraries. */
31
32 #include <stdio.h>
33 #include <string.h>
34
35 /* Local stuff. */
36
37 #include "tcpd.h"
38
39 /*
40 * When a string has the value STRING_UNKNOWN, it means: don't bother, I
41 * tried to look up the data but it was unavailable for some reason. When a
42 * host name has the value STRING_PARANOID it means there was a name/address
43 * conflict.
44 */
45 char unknown[] = STRING_UNKNOWN;
46 char paranoid[] = STRING_PARANOID;
47
48 /* eval_user - look up user name */
49
eval_user(request)50 char *eval_user(request)
51 struct request_info *request;
52 {
53 if (request->user[0] == 0) {
54 strcpy(request->user, unknown);
55 if (request->sink == 0 && request->client->sin && request->server->sin)
56 rfc931(request->client->sin, request->server->sin, request->user);
57 }
58 return (request->user);
59 }
60
61 /* eval_hostaddr - look up printable address */
62
eval_hostaddr(host)63 char *eval_hostaddr(host)
64 struct host_info *host;
65 {
66 if (host->addr[0] == 0) {
67 strcpy(host->addr, unknown);
68 if (host->request->hostaddr != 0)
69 host->request->hostaddr(host);
70 }
71 return (host->addr);
72 }
73
74 /* eval_hostname - look up host name */
75
eval_hostname(host)76 char *eval_hostname(host)
77 struct host_info *host;
78 {
79 if (host->name[0] == 0) {
80 strcpy(host->name, unknown);
81 if (host->request->hostname != 0)
82 host->request->hostname(host);
83 }
84 return (host->name);
85 }
86
87 /* eval_hostinfo - return string with host name (preferred) or address */
88
eval_hostinfo(host)89 char *eval_hostinfo(host)
90 struct host_info *host;
91 {
92 char *hostname;
93
94 #ifndef ALWAYS_HOSTNAME /* no implicit host lookups */
95 if (host->name[0] == 0)
96 return (eval_hostaddr(host));
97 #endif
98 hostname = eval_hostname(host);
99 if (HOSTNAME_KNOWN(hostname)) {
100 return (host->name);
101 } else {
102 return (eval_hostaddr(host));
103 }
104 }
105
106 /* eval_client - return string with as much about the client as we know */
107
eval_client(request)108 char *eval_client(request)
109 struct request_info *request;
110 {
111 static char both[2 * STRING_LENGTH];
112 char *hostinfo = eval_hostinfo(request->client);
113
114 #ifndef ALWAYS_RFC931 /* no implicit user lookups */
115 if (request->user[0] == 0)
116 return (hostinfo);
117 #endif
118 if (STR_NE(eval_user(request), unknown)) {
119 sprintf(both, "%s@%s", request->user, hostinfo);
120 return (both);
121 } else {
122 return (hostinfo);
123 }
124 }
125
126 /* eval_server - return string with as much about the server as we know */
127
eval_server(request)128 char *eval_server(request)
129 struct request_info *request;
130 {
131 static char both[2 * STRING_LENGTH];
132 char *host = eval_hostinfo(request->server);
133 char *daemon = eval_daemon(request);
134
135 if (STR_NE(host, unknown)) {
136 sprintf(both, "%s@%s", daemon, host);
137 return (both);
138 } else {
139 return (daemon);
140 }
141 }
142