1 /* $NetBSD: expand_hostname.c,v 1.2 2017/01/28 21:31:49 christos Exp $ */
2
3 /*
4 * Copyright (c) 1999 - 2001 Kungliga Tekniska Högskolan
5 * (Royal Institute of Technology, Stockholm, Sweden).
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * 3. Neither the name of the Institute nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 #include "krb5_locl.h"
37
38 static krb5_error_code
copy_hostname(krb5_context context,const char * orig_hostname,char ** new_hostname)39 copy_hostname(krb5_context context,
40 const char *orig_hostname,
41 char **new_hostname)
42 {
43 *new_hostname = strdup (orig_hostname);
44 if (*new_hostname == NULL)
45 return krb5_enomem(context);
46 strlwr (*new_hostname);
47 return 0;
48 }
49
50 /**
51 * krb5_expand_hostname() tries to make orig_hostname into a more
52 * canonical one in the newly allocated space returned in
53 * new_hostname.
54
55 * @param context a Keberos context
56 * @param orig_hostname hostname to canonicalise.
57 * @param new_hostname output hostname, caller must free hostname with
58 * krb5_xfree().
59 *
60 * @return Return an error code or 0, see krb5_get_error_message().
61 *
62 * @ingroup krb5_support
63 */
64
65 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_expand_hostname(krb5_context context,const char * orig_hostname,char ** new_hostname)66 krb5_expand_hostname (krb5_context context,
67 const char *orig_hostname,
68 char **new_hostname)
69 {
70 struct addrinfo *ai, *a, hints;
71 int error;
72
73 if ((context->flags & KRB5_CTX_F_DNS_CANONICALIZE_HOSTNAME) == 0)
74 return copy_hostname (context, orig_hostname, new_hostname);
75
76 memset (&hints, 0, sizeof(hints));
77 hints.ai_flags = AI_CANONNAME;
78
79 error = getaddrinfo (orig_hostname, NULL, &hints, &ai);
80 if (error)
81 return copy_hostname (context, orig_hostname, new_hostname);
82 for (a = ai; a != NULL; a = a->ai_next) {
83 if (a->ai_canonname != NULL) {
84 *new_hostname = strdup (a->ai_canonname);
85 freeaddrinfo (ai);
86 if (*new_hostname == NULL)
87 return krb5_enomem(context);
88 else
89 return 0;
90 }
91 }
92 freeaddrinfo (ai);
93 return copy_hostname (context, orig_hostname, new_hostname);
94 }
95
96 /*
97 * handle the case of the hostname being unresolvable and thus identical
98 */
99
100 static krb5_error_code
vanilla_hostname(krb5_context context,const char * orig_hostname,char ** new_hostname,char *** realms)101 vanilla_hostname (krb5_context context,
102 const char *orig_hostname,
103 char **new_hostname,
104 char ***realms)
105 {
106 krb5_error_code ret;
107
108 ret = copy_hostname (context, orig_hostname, new_hostname);
109 if (ret)
110 return ret;
111 strlwr (*new_hostname);
112
113 ret = krb5_get_host_realm (context, *new_hostname, realms);
114 if (ret) {
115 free (*new_hostname);
116 return ret;
117 }
118 return 0;
119 }
120
121 /**
122 * krb5_expand_hostname_realms() expands orig_hostname to a name we
123 * believe to be a hostname in newly allocated space in new_hostname
124 * and return the realms new_hostname is believed to belong to in
125 * realms.
126 *
127 * @param context a Keberos context
128 * @param orig_hostname hostname to canonicalise.
129 * @param new_hostname output hostname, caller must free hostname with
130 * krb5_xfree().
131 * @param realms output possible realms, is an array that is terminated
132 * with NULL. Caller must free with krb5_free_host_realm().
133 *
134 * @return Return an error code or 0, see krb5_get_error_message().
135 *
136 * @ingroup krb5_support
137 */
138
139 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_expand_hostname_realms(krb5_context context,const char * orig_hostname,char ** new_hostname,char *** realms)140 krb5_expand_hostname_realms (krb5_context context,
141 const char *orig_hostname,
142 char **new_hostname,
143 char ***realms)
144 {
145 struct addrinfo *ai, *a, hints;
146 int error;
147 krb5_error_code ret = 0;
148
149 if ((context->flags & KRB5_CTX_F_DNS_CANONICALIZE_HOSTNAME) == 0)
150 return vanilla_hostname (context, orig_hostname, new_hostname,
151 realms);
152
153 memset (&hints, 0, sizeof(hints));
154 hints.ai_flags = AI_CANONNAME;
155
156 error = getaddrinfo (orig_hostname, NULL, &hints, &ai);
157 if (error)
158 return vanilla_hostname (context, orig_hostname, new_hostname,
159 realms);
160
161 for (a = ai; a != NULL; a = a->ai_next) {
162 if (a->ai_canonname != NULL) {
163 ret = copy_hostname (context, a->ai_canonname, new_hostname);
164 if (ret) {
165 freeaddrinfo (ai);
166 return ret;
167 }
168 strlwr (*new_hostname);
169 ret = krb5_get_host_realm (context, *new_hostname, realms);
170 if (ret == 0) {
171 freeaddrinfo (ai);
172 return 0;
173 }
174 free (*new_hostname);
175 }
176 }
177 freeaddrinfo(ai);
178 return vanilla_hostname (context, orig_hostname, new_hostname, realms);
179 }
180