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 H��gskolan
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
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	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
65KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
66krb5_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
100static krb5_error_code
101vanilla_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
139KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
140krb5_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