1/*
2 * Copyright (c) 1999 - 2001 Kungliga Tekniska H�gskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * 3. Neither the name of the Institute nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include "krb5_locl.h"
35
36RCSID("$Id: expand_hostname.c 22229 2007-12-08 21:40:59Z lha $");
37
38static krb5_error_code
39copy_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	krb5_set_error_string(context, "malloc: out of memory");
46	return ENOMEM;
47    }
48    strlwr (*new_hostname);
49    return 0;
50}
51
52/*
53 * Try to make `orig_hostname' into a more canonical one in the newly
54 * allocated space returned in `new_hostname'.
55 */
56
57krb5_error_code KRB5_LIB_FUNCTION
58krb5_expand_hostname (krb5_context context,
59		      const char *orig_hostname,
60		      char **new_hostname)
61{
62    struct addrinfo *ai, *a, hints;
63    int error;
64
65    if ((context->flags & KRB5_CTX_F_DNS_CANONICALIZE_HOSTNAME) == 0)
66	return copy_hostname (context, orig_hostname, new_hostname);
67
68    memset (&hints, 0, sizeof(hints));
69    hints.ai_flags = AI_CANONNAME;
70
71    error = getaddrinfo (orig_hostname, NULL, &hints, &ai);
72    if (error)
73	return copy_hostname (context, orig_hostname, new_hostname);
74    for (a = ai; a != NULL; a = a->ai_next) {
75	if (a->ai_canonname != NULL) {
76	    *new_hostname = strdup (a->ai_canonname);
77	    freeaddrinfo (ai);
78	    if (*new_hostname == NULL) {
79		krb5_set_error_string(context, "malloc: out of memory");
80		return ENOMEM;
81	    } else {
82		return 0;
83	    }
84	}
85    }
86    freeaddrinfo (ai);
87    return copy_hostname (context, orig_hostname, new_hostname);
88}
89
90/*
91 * handle the case of the hostname being unresolvable and thus identical
92 */
93
94static krb5_error_code
95vanilla_hostname (krb5_context context,
96		  const char *orig_hostname,
97		  char **new_hostname,
98		  char ***realms)
99{
100    krb5_error_code ret;
101
102    ret = copy_hostname (context, orig_hostname, new_hostname);
103    if (ret)
104	return ret;
105    strlwr (*new_hostname);
106
107    ret = krb5_get_host_realm (context, *new_hostname, realms);
108    if (ret) {
109	free (*new_hostname);
110	return ret;
111    }
112    return 0;
113}
114
115/*
116 * expand `hostname' to a name we believe to be a hostname in newly
117 * allocated space in `host' and return realms in `realms'.
118 */
119
120krb5_error_code KRB5_LIB_FUNCTION
121krb5_expand_hostname_realms (krb5_context context,
122			     const char *orig_hostname,
123			     char **new_hostname,
124			     char ***realms)
125{
126    struct addrinfo *ai, *a, hints;
127    int error;
128    krb5_error_code ret = 0;
129
130    if ((context->flags & KRB5_CTX_F_DNS_CANONICALIZE_HOSTNAME) == 0)
131	return vanilla_hostname (context, orig_hostname, new_hostname,
132				 realms);
133
134    memset (&hints, 0, sizeof(hints));
135    hints.ai_flags = AI_CANONNAME;
136
137    error = getaddrinfo (orig_hostname, NULL, &hints, &ai);
138    if (error)
139	return vanilla_hostname (context, orig_hostname, new_hostname,
140				 realms);
141
142    for (a = ai; a != NULL; a = a->ai_next) {
143	if (a->ai_canonname != NULL) {
144	    ret = copy_hostname (context, a->ai_canonname, new_hostname);
145	    if (ret) {
146		freeaddrinfo (ai);
147		return ret;
148	    }
149	    strlwr (*new_hostname);
150	    ret = krb5_get_host_realm (context, *new_hostname, realms);
151	    if (ret == 0) {
152		freeaddrinfo (ai);
153		return 0;
154	    }
155	    free (*new_hostname);
156	}
157    }
158    freeaddrinfo(ai);
159    return vanilla_hostname (context, orig_hostname, new_hostname, realms);
160}
161