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34 #include "krb5_locl.h"
37 RCSID("$Id: get_host_realm.c,v 1.29 2002/08/28 13:36:57 nectar Exp $");
39 /* To automagically find the correct realm of a host (without
40 * [domain_realm] in krb5.conf) add a text record for your domain with
41 * the name of your realm, like this:
43 * _kerberos IN TXT "FOO.SE"
45 * The search is recursive, so you can add entries for specific
46 * hosts. To find the realm of host a.b.c, it first tries
47 * _kerberos.a.b.c, then _kerberos.b.c and so on.
49 * This method is described in draft-ietf-cat-krb-dns-locate-03.txt.
54 copy_txt_to_realms (struct resource_record *head,
57 struct resource_record *rr;
60 for(n = 0, rr = head; rr; rr = rr->next)
61 if (rr->type == T_TXT)
67 *realms = malloc ((n + 1) * sizeof(krb5_realm));
71 for (i = 0; i < n + 1; ++i)
74 for (i = 0, rr = head; rr; rr = rr->next) {
75 if (rr->type == T_TXT) {
78 tmp = strdup(rr->u.txt);
80 for (i = 0; i < n; ++i)
93 dns_find_realm(krb5_context context,
97 static char *default_labels[] = { "_kerberos", NULL };
98 char dom[MAXHOSTNAMELEN];
103 labels = krb5_config_get_strings(context, NULL, "libdefaults",
104 "dns_lookup_realm_labels", NULL);
106 labels = default_labels;
109 for (i = 0; labels[i] != NULL; i++) {
110 if(snprintf(dom, sizeof(dom), "%s.%s.", labels[i], domain) >=
113 r = dns_lookup(dom, "TXT");
115 ret = copy_txt_to_realms (r->head, realms);
125 * Try to figure out what realms host in `domain' belong to from the
126 * configuration file.
130 config_find_realm(krb5_context context,
134 char **tmp = krb5_config_get_strings (context, NULL,
146 * This function assumes that `host' is a FQDN (and doesn't handle the
147 * special case of host == NULL either).
148 * Try to find mapping in the config file or DNS and it that fails,
149 * fall back to guessing
153 krb5_get_host_realm_int (krb5_context context,
155 krb5_boolean use_dns,
159 krb5_boolean dns_locate_enable;
161 dns_locate_enable = krb5_config_get_bool_default(context, NULL, TRUE,
162 "libdefaults", "dns_lookup_realm", NULL);
163 for (p = host; p != NULL; p = strchr (p + 1, '.')) {
164 if(config_find_realm(context, p, realms) == 0) {
165 if(strcasecmp(*realms[0], "dns_locate") == 0) {
167 for (q = host; q != NULL; q = strchr(q + 1, '.'))
168 if(dns_find_realm(context, q, realms) == 0)
174 else if(use_dns && dns_locate_enable) {
175 if(dns_find_realm(context, p, realms) == 0)
179 p = strchr(host, '.');
182 *realms = malloc(2 * sizeof(krb5_realm));
183 if (*realms == NULL) {
184 krb5_set_error_string(context, "malloc: out of memory");
188 (*realms)[0] = strdup(p);
189 if((*realms)[0] == NULL) {
191 krb5_set_error_string(context, "malloc: out of memory");
194 strupr((*realms)[0]);
198 krb5_set_error_string(context, "unable to find realm of host %s", host);
199 return KRB5_ERR_HOST_REALM_UNKNOWN;
203 * Return the realm(s) of `host' as a NULL-terminated list in `realms'.
207 krb5_get_host_realm(krb5_context context,
211 char hostname[MAXHOSTNAMELEN];
214 if (gethostname (hostname, sizeof(hostname)))
219 return krb5_get_host_realm_int (context, host, 1, realms);