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