LCOV - code coverage report
Current view: top level - source4/heimdal/lib/krb5 - get_host_realm.c (source / functions) Hit Total Coverage
Test: coverage report for abartlet/fix-coverage dd10fb34 Lines: 33 100 33.0 %
Date: 2021-09-23 10:06:22 Functions: 3 5 60.0 %

          Line data    Source code
       1             : /*
       2             :  * Copyright (c) 1997 - 2005 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             : #include <resolve.h>
      36             : 
      37             : /* To automagically find the correct realm of a host (without
      38             :  * [domain_realm] in krb5.conf) add a text record for your domain with
      39             :  * the name of your realm, like this:
      40             :  *
      41             :  * _kerberos    IN      TXT     "FOO.SE"
      42             :  *
      43             :  * The search is recursive, so you can add entries for specific
      44             :  * hosts. To find the realm of host a.b.c, it first tries
      45             :  * _kerberos.a.b.c, then _kerberos.b.c and so on.
      46             :  *
      47             :  * This method is described in draft-ietf-cat-krb-dns-locate-03.txt.
      48             :  *
      49             :  */
      50             : 
      51             : static int
      52           0 : copy_txt_to_realms (struct rk_resource_record *head,
      53             :                     krb5_realm **realms)
      54             : {
      55             :     struct rk_resource_record *rr;
      56             :     unsigned int n, i;
      57             : 
      58           0 :     for(n = 0, rr = head; rr; rr = rr->next)
      59           0 :         if (rr->type == rk_ns_t_txt)
      60           0 :             ++n;
      61             : 
      62           0 :     if (n == 0)
      63           0 :         return -1;
      64             : 
      65           0 :     *realms = malloc ((n + 1) * sizeof(krb5_realm));
      66           0 :     if (*realms == NULL)
      67           0 :         return -1;
      68             : 
      69           0 :     for (i = 0; i < n + 1; ++i)
      70           0 :         (*realms)[i] = NULL;
      71             : 
      72           0 :     for (i = 0, rr = head; rr; rr = rr->next) {
      73           0 :         if (rr->type == rk_ns_t_txt) {
      74             :             char *tmp;
      75             : 
      76           0 :             tmp = strdup(rr->u.txt);
      77           0 :             if (tmp == NULL) {
      78           0 :                 for (i = 0; i < n; ++i)
      79           0 :                     free ((*realms)[i]);
      80           0 :                 free (*realms);
      81           0 :                 return -1;
      82             :             }
      83           0 :             (*realms)[i] = tmp;
      84           0 :             ++i;
      85             :         }
      86             :     }
      87           0 :     return 0;
      88             : }
      89             : 
      90             : static int
      91           0 : dns_find_realm(krb5_context context,
      92             :                const char *domain,
      93             :                krb5_realm **realms)
      94             : {
      95             :     static const char *default_labels[] = { "_kerberos", NULL };
      96             :     char dom[MAXHOSTNAMELEN];
      97             :     struct rk_dns_reply *r;
      98             :     const char **labels;
      99             :     char **config_labels;
     100             :     int i, ret;
     101             : 
     102           0 :     config_labels = krb5_config_get_strings(context, NULL, "libdefaults",
     103             :                                             "dns_lookup_realm_labels", NULL);
     104           0 :     if(config_labels != NULL)
     105           0 :         labels = (const char **)config_labels;
     106             :     else
     107           0 :         labels = default_labels;
     108           0 :     if(*domain == '.')
     109           0 :         domain++;
     110           0 :     for (i = 0; labels[i] != NULL; i++) {
     111           0 :         ret = snprintf(dom, sizeof(dom), "%s.%s.", labels[i], domain);
     112           0 :         if(ret < 0 || (size_t)ret >= sizeof(dom)) {
     113           0 :             if (config_labels)
     114           0 :                 krb5_config_free_strings(config_labels);
     115           0 :             return -1;
     116             :         }
     117           0 :         r = rk_dns_lookup(dom, "TXT");
     118           0 :         if(r != NULL) {
     119           0 :             ret = copy_txt_to_realms (r->head, realms);
     120           0 :             rk_dns_free_data(r);
     121           0 :             if(ret == 0) {
     122           0 :                 if (config_labels)
     123           0 :                     krb5_config_free_strings(config_labels);
     124           0 :                 return 0;
     125             :             }
     126             :         }
     127             :     }
     128           0 :     if (config_labels)
     129           0 :         krb5_config_free_strings(config_labels);
     130           0 :     return -1;
     131             : }
     132             : 
     133             : /*
     134             :  * Try to figure out what realms host in `domain' belong to from the
     135             :  * configuration file.
     136             :  */
     137             : 
     138             : static int
     139       37087 : config_find_realm(krb5_context context,
     140             :                   const char *domain,
     141             :                   krb5_realm **realms)
     142             : {
     143       37837 :     char **tmp = krb5_config_get_strings (context, NULL,
     144             :                                           "domain_realm",
     145             :                                           domain,
     146             :                                           NULL);
     147             : 
     148       37837 :     if (tmp == NULL)
     149       37087 :         return -1;
     150           0 :     *realms = tmp;
     151           0 :     return 0;
     152             : }
     153             : 
     154             : /*
     155             :  * This function assumes that `host' is a FQDN (and doesn't handle the
     156             :  * special case of host == NULL either).
     157             :  * Try to find mapping in the config file or DNS and it that fails,
     158             :  * fall back to guessing
     159             :  */
     160             : 
     161             : KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
     162       22491 : _krb5_get_host_realm_int (krb5_context context,
     163             :                           const char *host,
     164             :                           krb5_boolean use_dns,
     165             :                           krb5_realm **realms)
     166             : {
     167             :     const char *p, *q;
     168             :     krb5_boolean dns_locate_enable;
     169             : 
     170       22491 :     dns_locate_enable = krb5_config_get_bool_default(context, NULL, TRUE,
     171             :         "libdefaults", "dns_lookup_realm", NULL);
     172       60328 :     for (p = host; p != NULL; p = strchr (p + 1, '.')) {
     173       37837 :         if(config_find_realm(context, p, realms) == 0) {
     174           0 :             if(strcasecmp(*realms[0], "dns_locate") == 0) {
     175           0 :                 if(use_dns)
     176           0 :                     for (q = host; q != NULL; q = strchr(q + 1, '.'))
     177           0 :                         if(dns_find_realm(context, q, realms) == 0)
     178           0 :                             return 0;
     179           0 :                 continue;
     180             :             } else
     181           0 :                 return 0;
     182             :         }
     183       37837 :         else if(use_dns && dns_locate_enable) {
     184           0 :             if(dns_find_realm(context, p, realms) == 0)
     185           0 :                 return 0;
     186             :         }
     187             :     }
     188       22491 :     p = strchr(host, '.');
     189       22491 :     if(p != NULL) {
     190        4764 :         p++;
     191        4764 :         *realms = malloc(2 * sizeof(krb5_realm));
     192        4764 :         if (*realms == NULL) {
     193           0 :             krb5_set_error_message(context, ENOMEM, N_("malloc: out of memory", ""));
     194           0 :             return ENOMEM;
     195             :         }
     196             : 
     197        4764 :         (*realms)[0] = strdup(p);
     198        4764 :         if((*realms)[0] == NULL) {
     199           0 :             free(*realms);
     200           0 :             krb5_set_error_message(context, ENOMEM, N_("malloc: out of memory", ""));
     201           0 :             return ENOMEM;
     202             :         }
     203        4764 :         strupr((*realms)[0]);
     204        4764 :         (*realms)[1] = NULL;
     205        4764 :         return 0;
     206             :     }
     207       17727 :     krb5_set_error_message(context, KRB5_ERR_HOST_REALM_UNKNOWN,
     208       17727 :                            N_("unable to find realm of host %s", ""),
     209             :                            host);
     210       17727 :     return KRB5_ERR_HOST_REALM_UNKNOWN;
     211             : }
     212             : 
     213             : /*
     214             :  * Return the realm(s) of `host' as a NULL-terminated list in
     215             :  * `realms'. Free `realms' with krb5_free_host_realm().
     216             :  */
     217             : 
     218             : KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
     219       22491 : krb5_get_host_realm(krb5_context context,
     220             :                     const char *targethost,
     221             :                     krb5_realm **realms)
     222             : {
     223       22491 :     const char *host = targethost;
     224             :     char hostname[MAXHOSTNAMELEN];
     225             :     krb5_error_code ret;
     226             :     int use_dns;
     227             : 
     228       22491 :     if (host == NULL) {
     229          12 :         if (gethostname (hostname, sizeof(hostname))) {
     230           0 :             *realms = NULL;
     231           0 :             return errno;
     232             :         }
     233          12 :         host = hostname;
     234             :     }
     235             : 
     236             :     /*
     237             :      * If our local hostname is without components, don't even try to dns.
     238             :      */
     239             : 
     240       22491 :     use_dns = (strchr(host, '.') != NULL);
     241             : 
     242       22491 :     ret = _krb5_get_host_realm_int (context, host, use_dns, realms);
     243       22491 :     if (ret && targethost != NULL) {
     244             :         /*
     245             :          * If there was no realm mapping for the host (and we wasn't
     246             :          * looking for ourself), guess at the local realm, maybe our
     247             :          * KDC knows better then we do and we get a referral back.
     248             :          */
     249       17727 :         ret = krb5_get_default_realms(context, realms);
     250       17727 :         if (ret) {
     251           0 :             krb5_set_error_message(context, KRB5_ERR_HOST_REALM_UNKNOWN,
     252           0 :                                    N_("Unable to find realm of host %s", ""),
     253             :                                    host);
     254           0 :             return KRB5_ERR_HOST_REALM_UNKNOWN;
     255             :         }
     256             :     }
     257       21741 :     return ret;
     258             : }

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