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/*
* MIT Kerberos KDC database backend for FreeIPA
*
* Authors: Simo Sorce <ssorce@redhat.com>
*
* Copyright (C) 2011 Simo Sorce, Red Hat
* see file 'COPYING' for use and warranty information
*
* This program is free software you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "ipa_kdb.h"
static char *acl_attrs[] = {
"objectClass",
"memberPrincipal",
NULL
};
static char *search_attrs[] = {
"ipaAllowToImpersonate",
"ipaAllowedTarget",
NULL
};
static krb5_error_code ipadb_get_delegation_acl(krb5_context kcontext,
char *srv_principal,
LDAPMessage **results)
{
struct ipadb_context *ipactx;
krb5_error_code kerr;
char *filter = NULL;
int ret;
ipactx = ipadb_get_context(kcontext);
if (!ipactx) {
return KRB5_KDB_DBNOTINITED;
}
ret = asprintf(&filter,
"(&(objectclass=ipaKrb5DelegationACL)"
"(memberPrincipal=%s))", srv_principal);
if (ret == -1) {
kerr = ENOMEM;
goto done;
}
/* == Search ACL info == */
kerr = ipadb_deref_search(ipactx, ipactx->base,
LDAP_SCOPE_SUBTREE, filter, acl_attrs,
search_attrs, acl_attrs, results);
done:
free(filter);
return kerr;
}
static bool ipadb_match_member(char *princ, LDAPDerefRes *dres)
{
LDAPDerefVal *dval;
int i;
for (dval = dres->attrVals; dval; dval = dval->next) {
if (strcasecmp(dval->type, "memberPrincipal") != 0) {
continue;
}
for (i = 0; dval->vals[i].bv_val != NULL; i++) {
/* FIXME: use utf8 aware comparison ? */
/* FIXME: support wildcards ? */
if (strncasecmp(princ, dval->vals[i].bv_val,
dval->vals[i].bv_len) == 0) {
return true;
}
}
}
return false;
}
static krb5_error_code ipadb_match_acl(krb5_context kcontext,
LDAPMessage *results,
krb5_const_principal client,
krb5_const_principal target)
{
struct ipadb_context *ipactx;
krb5_error_code kerr;
LDAPMessage *lentry;
LDAPDerefRes *deref_results;
LDAPDerefRes *dres;
char *client_princ = NULL;
char *target_princ = NULL;
bool client_missing;
bool client_found;
bool target_found;
int ret;
ipactx = ipadb_get_context(kcontext);
if (!ipactx) {
return KRB5_KDB_DBNOTINITED;
}
kerr = krb5_unparse_name(kcontext, client, &client_princ);
if (kerr != 0) {
goto done;
}
kerr = krb5_unparse_name(kcontext, target, &target_princ);
if (kerr != 0) {
goto done;
}
lentry = ldap_first_entry(ipactx->lcontext, results);
if (!lentry) {
kerr = ENOENT;
goto done;
}
/* the default is that we fail */
kerr = ENOENT;
while (lentry) {
/* both client and target must be found in the same ACI */
client_missing = true;
client_found = false;
target_found = false;
ret = ipadb_ldap_deref_results(ipactx->lcontext, lentry,
&deref_results);
switch (ret) {
case 0:
for (dres = deref_results; dres; dres = dres->next) {
if (client_found == false &&
strcasecmp(dres->derefAttr, "ipaAllowToImpersonate") == 0) {
/* NOTE: client_missing is used to signal that the
* attribute was completely missing. This signals that
* ANY client is allowed to be impersonated.
* This logic is valid only for clients, not for targets */
client_missing = false;
client_found = ipadb_match_member(client_princ, dres);
}
if (target_found == false &&
strcasecmp(dres->derefAttr, "ipaAllowedTarget") == 0) {
target_found = ipadb_match_member(target_princ, dres);
}
}
ldap_derefresponse_free(deref_results);
break;
case ENOENT:
break;
default:
kerr = ret;
goto done;
}
if ((client_found == true || client_missing == true) &&
target_found == true) {
kerr = 0;
goto done;
}
lentry = ldap_next_entry(ipactx->lcontext, lentry);
}
done:
krb5_free_unparsed_name(kcontext, client_princ);
krb5_free_unparsed_name(kcontext, target_princ);
return kerr;
}
/* Ok terminology is confusing here so read carefully:
* here 'proxy' is the service for which 'server' wants a ticket on behalf of
* 'client' */
krb5_error_code ipadb_check_allowed_to_delegate(krb5_context kcontext,
krb5_const_principal client,
const krb5_db_entry *server,
krb5_const_principal proxy)
{
krb5_error_code kerr;
char *srv_principal = NULL;
LDAPMessage *res = NULL;
kerr = krb5_unparse_name(kcontext, server->princ, &srv_principal);
if (kerr) {
goto done;
}
kerr = ipadb_get_delegation_acl(kcontext, srv_principal, &res);
if (kerr) {
goto done;
}
kerr = ipadb_match_acl(kcontext, res, client, proxy);
if (kerr) {
goto done;
}
done:
krb5_free_unparsed_name(kcontext, srv_principal);
ldap_msgfree(res);
return kerr;
}
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