lib/krb5/expand_hostname.c

   1 /*
   2  * Copyright (c) 1999 - 2001 Kungliga Tekniska Högskolan
   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
  36 static krb5_error_code
  37 copy_hostname(krb5_context context,
  38               const char *orig_hostname,
  39               char **new_hostname)
  40 {
  41     *new_hostname = strdup (orig_hostname);
  42     if (*new_hostname == NULL) {
  43         krb5_set_error_message(context, ENOMEM,
  44                                N_("malloc: out of memory", ""));
  45         return ENOMEM;
  46     }
  47     strlwr (*new_hostname);
  48     return 0;
  49 }
  50
  51 /**
  52  * krb5_expand_hostname() tries to make orig_hostname into a more
  53  * canonical one in the newly allocated space returned in
  54  * new_hostname.
  55
  56  * @param context a Keberos context
  57  * @param orig_hostname hostname to canonicalise.
  58  * @param new_hostname output hostname, caller must free hostname with
  59  *        krb5_xfree().
  60  *
  61  * @return Return an error code or 0, see krb5_get_error_message().
  62  *
  63  * @ingroup krb5_support
  64  */
  65
  66 krb5_error_code KRB5_LIB_FUNCTION
  67 krb5_expand_hostname (krb5_context context,
  68                       const char *orig_hostname,
  69                       char **new_hostname)
  70 {
  71     struct addrinfo *ai, *a, hints;
  72     int error;
  73
  74     if ((context->flags & KRB5_CTX_F_DNS_CANONICALIZE_HOSTNAME) == 0)
  75         return copy_hostname (context, orig_hostname, new_hostname);
  76
  77     memset (&hints, 0, sizeof(hints));
  78     hints.ai_flags = AI_CANONNAME;
  79
  80     error = getaddrinfo (orig_hostname, NULL, &hints, &ai);
  81     if (error)
  82         return copy_hostname (context, orig_hostname, new_hostname);
  83     for (a = ai; a != NULL; a = a->ai_next) {
  84         if (a->ai_canonname != NULL) {
  85             *new_hostname = strdup (a->ai_canonname);
  86             freeaddrinfo (ai);
  87             if (*new_hostname == NULL) {
  88                 krb5_set_error_message(context, ENOMEM,
  89                                        N_("malloc: out of memory", ""));
  90                 return ENOMEM;
  91             } else {
  92                 return 0;
  93             }
  94         }
  95     }
  96     freeaddrinfo (ai);
  97     return copy_hostname (context, orig_hostname, new_hostname);
  98 }
  99
 100 /*
 101  * handle the case of the hostname being unresolvable and thus identical
 102  */
 103
 104 static krb5_error_code
 105 vanilla_hostname (krb5_context context,
 106                   const char *orig_hostname,
 107                   char **new_hostname,
 108                   char ***realms)
 109 {
 110     krb5_error_code ret;
 111
 112     ret = copy_hostname (context, orig_hostname, new_hostname);
 113     if (ret)
 114         return ret;
 115     strlwr (*new_hostname);
 116
 117     ret = krb5_get_host_realm (context, *new_hostname, realms);
 118     if (ret) {
 119         free (*new_hostname);
 120         return ret;
 121     }
 122     return 0;
 123 }
 124
 125 /**
 126  * krb5_expand_hostname_realms() expands orig_hostname to a name we
 127  * believe to be a hostname in newly allocated space in new_hostname
 128  * and return the realms new_hostname is believed to belong to in
 129  * realms.
 130  *
 131  * @param context a Keberos context
 132  * @param orig_hostname hostname to canonicalise.
 133  * @param new_hostname output hostname, caller must free hostname with
 134  *        krb5_xfree().
 135  * @param realms output possible realms, is an array that is terminated
 136  *        with NULL. Caller must free with krb5_free_host_realm().
 137  *
 138  * @return Return an error code or 0, see krb5_get_error_message().
 139  *
 140  * @ingroup krb5_support
 141  */
 142
 143 krb5_error_code KRB5_LIB_FUNCTION
 144 krb5_expand_hostname_realms (krb5_context context,
 145                              const char *orig_hostname,
 146                              char **new_hostname,
 147                              char ***realms)
 148 {
 149     struct addrinfo *ai, *a, hints;
 150     int error;
 151     krb5_error_code ret = 0;
 152
 153     if ((context->flags & KRB5_CTX_F_DNS_CANONICALIZE_HOSTNAME) == 0)
 154         return vanilla_hostname (context, orig_hostname, new_hostname,
 155                                  realms);
 156
 157     memset (&hints, 0, sizeof(hints));
 158     hints.ai_flags = AI_CANONNAME;
 159
 160     error = getaddrinfo (orig_hostname, NULL, &hints, &ai);
 161     if (error)
 162         return vanilla_hostname (context, orig_hostname, new_hostname,
 163                                  realms);
 164
 165     for (a = ai; a != NULL; a = a->ai_next) {
 166         if (a->ai_canonname != NULL) {
 167             ret = copy_hostname (context, a->ai_canonname, new_hostname);
 168             if (ret) {
 169                 freeaddrinfo (ai);
 170                 return ret;
 171             }
 172             strlwr (*new_hostname);
 173             ret = krb5_get_host_realm (context, *new_hostname, realms);
 174             if (ret == 0) {
 175                 freeaddrinfo (ai);
 176                 return 0;
 177             }
 178             free (*new_hostname);
 179         }
 180     }
 181     freeaddrinfo(ai);
 182     return vanilla_hostname (context, orig_hostname, new_hostname, realms);
 183 }