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/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* lib/krb5/os/hostream_domain.c - domain hostrealm module */
/*
* Copyright (C) 1990,1991,2002,2008,2009,2013 by the Massachusetts Institute
* of Technology. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* This file implements the built-in domain module for the hostrealm interface,
* which uses domain-based heuristics to determine the fallback realm of a
* host.
*/
#include "k5-int.h"
#include "os-proto.h"
#include <krb5/hostrealm_plugin.h>
#include <ctype.h>
static krb5_error_code
domain_fallback_realm(krb5_context context, krb5_hostrealm_moddata data,
const char *host, char ***realms_out)
{
krb5_error_code ret;
struct serverlist slist;
krb5_data drealm;
char *uhost = NULL, *p;
const char *suffix, *dot;
int limit;
*realms_out = NULL;
/* These heuristics don't apply to address literals. */
if (k5_is_numeric_address(host))
return KRB5_PLUGIN_NO_HANDLE;
/* Make an uppercase copy of host. */
uhost = strdup(host);
if (uhost == NULL)
return ENOMEM;
for (p = uhost; *p != '\0'; p++) {
if (islower((unsigned char)*p))
*p = toupper((unsigned char)*p);
}
/*
* Try searching domain suffixes as realms. This heuristic is turned off
* by default. If DNS lookups for KDCs are enabled (as they are by
* default), an attacker could control which domain component is used as
* the realm for a host.
*
* A realm_try_domains value of -1 (the default) means not to search at
* all, a value of 0 means to try only the full domain itself, 1 means to
* also try the parent domain, etc.. We will stop searching when we reach
* a suffix with only one label.
*/
ret = profile_get_integer(context->profile, KRB5_CONF_LIBDEFAULTS,
KRB5_CONF_REALM_TRY_DOMAINS, 0, -1, &limit);
if (ret)
return ret;
suffix = uhost;
while (limit-- >= 0 && (dot = strchr(suffix, '.')) != NULL) {
drealm = string2data((char *)suffix);
if (k5_locate_kdc(context, &drealm, &slist, FALSE, FALSE) == 0) {
k5_free_serverlist(&slist);
ret = k5_make_realmlist(suffix, realms_out);
goto cleanup;
}
suffix = dot + 1;
}
/*
* If that didn't succeed, use the upper-cased parent domain of the
* hostname, regardless of whether we can actually look it up as a realm.
*/
dot = strchr(uhost, '.');
if (dot != NULL)
ret = k5_make_realmlist(dot + 1, realms_out);
else
ret = KRB5_PLUGIN_NO_HANDLE;
cleanup:
free(uhost);
return ret;
}
static void
domain_free_realmlist(krb5_context context, krb5_hostrealm_moddata data,
char **list)
{
krb5_free_host_realm(context, list);
}
krb5_error_code
hostrealm_domain_initvt(krb5_context context, int maj_ver, int min_ver,
krb5_plugin_vtable vtable)
{
krb5_hostrealm_vtable vt = (krb5_hostrealm_vtable)vtable;
vt->name = "domain";
vt->fallback_realm = domain_fallback_realm;
vt->free_list = domain_free_realmlist;
return 0;
}
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