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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 *krbmkey_attrs[] = {
"krbMKey",
NULL
};
static krb5_error_code ipadb_fetch_master_key(struct ipadb_context *ipactx,
krb5_keyblock *key,
krb5_kvno *kvno)
{
LDAPMessage *res = NULL;
LDAPMessage *first;
struct berval **vals = NULL;
BerElement *be = NULL;
krb5_error_code kerr;
krb5_keyblock k;
int mkvno;
int ret;
int i;
if (!ipactx->lcontext) {
ret = ipadb_get_connection(ipactx);
if (ret != 0) {
kerr = KRB5_KDB_SERVER_INTERNAL_ERR;
goto done;
}
}
be = ber_alloc_t(LBER_USE_DER);
if (!be) {
kerr = ENOMEM;
goto done;
}
kerr = ipadb_simple_search(ipactx, ipactx->realm_base, LDAP_SCOPE_BASE,
"(krbMKey=*)", krbmkey_attrs, &res);
if (kerr) {
goto done;
}
first = ldap_first_entry(ipactx->lcontext, res);
if (!first) {
kerr = KRB5_KDB_NOENTRY;
goto done;
}
mkvno = 0;
k.contents = NULL;
vals = ldap_get_values_len(ipactx->lcontext, first, "krbmkey");
for (i = 0; vals[i]; i++) {
struct berval *mkey;
ber_tag_t tag;
ber_int_t tvno;
ber_int_t ttype;
ber_init2(be, vals[i], LBER_USE_DER);
tag = ber_scanf(be, "{i{iO}}", &tvno, &ttype, &mkey);
if (tag == LBER_ERROR) {
kerr = KRB5_KDB_SERVER_INTERNAL_ERR;
goto done;
}
if (tvno > mkvno) {
mkvno = tvno;
k.enctype = ttype;
k.length = mkey->bv_len;
if (k.contents) {
free(k.contents);
}
k.contents = malloc(k.length);
if (!k.contents) {
kerr = ENOMEM;
goto done;
}
memcpy(k.contents, mkey->bv_val, k.length);
}
ber_bvfree(mkey);
}
if (mkvno == 0) {
kerr = KRB5_KDB_NOENTRY;
goto done;
}
*kvno = mkvno;
key->magic = KV5M_KEYBLOCK;
key->enctype = k.enctype;
key->length = k.length;
key->contents = k.contents;
kerr = 0;
done:
if (be) {
ber_free(be, 0);
}
ldap_value_free_len(vals);
ldap_msgfree(res);
return kerr;
}
static krb5_error_code ipadb_store_master_key(struct ipadb_context *ipactx,
krb5_keylist_node *cur_key)
{
BerElement *be = NULL;
struct berval mkey;
ber_int_t tvno;
ber_int_t ttype;
LDAPMod **mods = NULL;
krb5_error_code kerr;
int ret;
if (!ipactx->lcontext) {
ret = ipadb_get_connection(ipactx);
if (ret != 0) {
kerr = KRB5_KDB_SERVER_INTERNAL_ERR;
goto done;
}
}
be = ber_alloc_t(LBER_USE_DER);
if (!be) {
kerr = ENOMEM;
goto done;
}
tvno = cur_key->kvno;
ttype = cur_key->keyblock.enctype;
mkey.bv_len = cur_key->keyblock.length;
mkey.bv_val = (void *)cur_key->keyblock.contents;
ret = ber_printf(be, "{i{iO}}", tvno, ttype, &mkey);
if (ret == -1) {
kerr = KRB5_KDB_INTERNAL_ERROR;
goto done;
}
mods = calloc(2, sizeof(LDAPMod *));
if (!mods) {
kerr = ENOMEM;
goto done;
}
mods[0] = calloc(1, sizeof(LDAPMod));
if (!mods[0]) {
kerr = ENOMEM;
goto done;
}
mods[0]->mod_op = LDAP_MOD_ADD | LDAP_MOD_BVALUES;
mods[0]->mod_type = strdup("krbMKey");
if (!mods[0]->mod_type) {
kerr = ENOMEM;
goto done;
}
mods[0]->mod_bvalues = calloc(2, sizeof(struct berval *));
if (!mods[0]->mod_bvalues) {
kerr = ENOMEM;
goto done;
}
ret = ber_flatten(be, &mods[0]->mod_bvalues[0]);
if (ret == -1) {
kerr = KRB5_KDB_INTERNAL_ERROR;
goto done;
}
kerr = ipadb_simple_modify(ipactx, ipactx->realm_base, mods);
kerr = 0;
done:
if (be) {
ber_free(be, 1);
}
ldap_mods_free(mods, 1);
return kerr;
}
static krb5_error_code ipadb_update_krbMKey(struct ipadb_context *ipactx,
krb5_keylist_node *master_key,
bool update)
{
krb5_error_code kerr;
LDAPMessage *res = NULL;
if (update) {
/* check if we need to update the master key in LDAP for
* older replicas, if the attr is found, keep it updated */
kerr = ipadb_simple_search(ipactx, ipactx->realm_base,
LDAP_SCOPE_BASE, "(krbMKey=*)",
krbmkey_attrs, &res);
switch (kerr) {
case 0:
ldap_msgfree(res);
break;
case KRB5_KDB_NOENTRY:
return 0;
default:
return kerr;
}
}
/* FIXME: on domain level X we may want to not add the key */
kerr = ipadb_store_master_key(ipactx, master_key);
if (kerr) {
com_err("IPA KDB driver", kerr,
"while storing master key (version %d)",
(int)master_key->kvno);
}
return kerr;
}
krb5_error_code ipadb_check_db_exists(struct ipadb_context *ipactx)
{
if (ipactx->special_flags & IPA_SPECIAL_CREATE_STEP) return EEXIST;
return 0;
}
/* See if we have a keytab, if not try to fetch the key from ldap, and
* stash it for the future (upgrade path) */
krb5_error_code ipadb_check_master_key(struct ipadb_context *ipactx)
{
krb5_error_code kerr;
char *cmname = NULL;
krb5_principal mname = NULL;
krb5_keyblock mkey = { 0 };
krb5_keylist_node *keylist;
krb5_kvno mkvno;
kerr = asprintf(&cmname, KRB5_KDB_M_NAME"@%s", ipactx->realm);
if (kerr < 0) return ENOMEM;
kerr = krb5_parse_name(ipactx->kcontext, cmname, &mname);
if (kerr) goto done;
kerr = krb5_db_fetch_mkey(ipactx->kcontext, mname, ENCTYPE_UNKNOWN,
0, 0, NULL, &mkvno, NULL, &mkey);
if (kerr == 0) kerr = ipadb_check_db_exists(ipactx);
if (kerr && (kerr != KRB5_KDB_CANTREAD_STORED)) goto done;
if (kerr == KRB5_KDB_CANTREAD_STORED) {
/* check if we have a key in LDAP, and stash it in the keytab */
kerr = ipadb_fetch_master_key(ipactx, &mkey, &mkvno);
if (kerr == 0) kerr = ipadb_check_db_exists(ipactx);
if (kerr) {
/* if we are setting up then lack of mkey is normal */
if (ipactx->special_flags & IPA_SPECIAL_CREATE_STEP) kerr = 0;
goto done;
}
kerr = krb5_db_store_master_key(ipactx->kcontext, NULL,
mname, mkvno, &mkey, NULL);
} else {
/* if override is set do extra checks on ldap keytab so that it
* is uploaded during initial setup if needed */
if (ipactx->special_flags & IPA_SPECIAL_OVERRIDE_RESTRICTION) {
krb5_keylist_node curkey = { mkey, mkvno, NULL };
kerr = ipadb_update_krbMKey(ipactx, &curkey, false);
if (kerr) goto done;
}
/* check if we have the latest kvno as current key. If not stash
* the new keys in the keytab */
kerr = krb5_db_fetch_mkey_list(ipactx->kcontext, mname, &mkey);
if (kerr) goto done;
keylist = krb5_db_mkey_list_alias(ipactx->kcontext);
if (keylist->kvno > mkvno) {
kerr = krb5_db_store_master_key_list(ipactx->kcontext, NULL,
mname, NULL);
/* we do not consider it fatal if this fails on update */
(void)ipadb_update_krbMKey(ipactx, keylist, true);
}
}
done:
krb5_free_keyblock_contents(ipactx->kcontext, &mkey);
krb5_free_principal(ipactx->kcontext, mname);
free(cmname);
return kerr;
}
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