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/*
ldb database library
Copyright (C) Nadezhda Ivanova 2010
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/>.
*/
/*
* Name: dsdb_access
*
* Description: utility functions for access checking on objects
*
* Authors: Nadezhda Ivanova
*/
#include "includes.h"
#include "ldb.h"
#include "ldb_module.h"
#include "ldb_errors.h"
#include "libcli/security/security.h"
#include "librpc/gen_ndr/ndr_security.h"
#include "libcli/ldap/ldap_ndr.h"
#include "param/param.h"
#include "auth/auth.h"
#include "dsdb/samdb/samdb.h"
#include "dsdb/common/util.h"
void dsdb_acl_debug(struct security_descriptor *sd,
struct security_token *token,
struct ldb_dn *dn,
bool denied,
int level)
{
if (denied) {
DEBUG(level, ("Access on %s denied", ldb_dn_get_linearized(dn)));
} else {
DEBUG(level, ("Access on %s granted", ldb_dn_get_linearized(dn)));
}
DEBUG(level,("Security context: %s\n",
ndr_print_struct_string(0,(ndr_print_fn_t)ndr_print_security_token,"", token)));
DEBUG(level,("Security descriptor: %s\n",
ndr_print_struct_string(0,(ndr_print_fn_t)ndr_print_security_descriptor,"", sd)));
}
int dsdb_get_sd_from_ldb_message(struct ldb_context *ldb,
TALLOC_CTX *mem_ctx,
struct ldb_message *acl_res,
struct security_descriptor **sd)
{
struct ldb_message_element *sd_element;
enum ndr_err_code ndr_err;
sd_element = ldb_msg_find_element(acl_res, "nTSecurityDescriptor");
if (sd_element == NULL) {
return ldb_error(ldb, LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS,
"nTSecurityDescriptor is missing");
}
*sd = talloc(mem_ctx, struct security_descriptor);
if(!*sd) {
return ldb_oom(ldb);
}
ndr_err = ndr_pull_struct_blob(&sd_element->values[0], *sd, *sd,
(ndr_pull_flags_fn_t)ndr_pull_security_descriptor);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
return ldb_operr(ldb);
}
return LDB_SUCCESS;
}
int dsdb_check_access_on_dn_internal(struct ldb_context *ldb,
struct ldb_result *acl_res,
TALLOC_CTX *mem_ctx,
struct security_token *token,
struct ldb_dn *dn,
uint32_t access_mask,
const struct GUID *guid)
{
struct security_descriptor *sd = NULL;
struct dom_sid *sid = NULL;
struct object_tree *root = NULL;
NTSTATUS status;
uint32_t access_granted;
int ret;
ret = dsdb_get_sd_from_ldb_message(ldb, mem_ctx, acl_res->msgs[0], &sd);
if (ret != LDB_SUCCESS) {
return ldb_operr(ldb);
}
/* Theoretically we pass the check if the object has no sd */
if (!sd) {
return LDB_SUCCESS;
}
sid = samdb_result_dom_sid(mem_ctx, acl_res->msgs[0], "objectSid");
if (guid) {
if (!insert_in_object_tree(mem_ctx, guid, access_mask, NULL,
&root)) {
return ldb_operr(ldb);
}
}
status = sec_access_check_ds(sd, token,
access_mask,
&access_granted,
root,
sid);
if (!NT_STATUS_IS_OK(status)) {
dsdb_acl_debug(sd,
token,
dn,
true,
10);
ldb_asprintf_errstring(ldb,
"dsdb_access: Access check failed on %s",
ldb_dn_get_linearized(dn));
return LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS;
}
return LDB_SUCCESS;
}
/* performs an access check from outside the module stack
* given the dn of the object to be checked, the required access
* guid is either the guid of the extended right, or NULL
*/
int dsdb_check_access_on_dn(struct ldb_context *ldb,
TALLOC_CTX *mem_ctx,
struct ldb_dn *dn,
struct security_token *token,
uint32_t access_mask,
const char *ext_right)
{
int ret;
struct GUID guid;
struct ldb_result *acl_res;
static const char *acl_attrs[] = {
"nTSecurityDescriptor",
"objectSid",
NULL
};
if (ext_right != NULL) {
NTSTATUS status = GUID_from_string(ext_right, &guid);
if (!NT_STATUS_IS_OK(status)) {
return LDB_ERR_OPERATIONS_ERROR;
}
}
/*
* We need AS_SYSTEM in order to get the nTSecurityDescriptor attribute.
* Also the result of this search not controlled by the client
* nor is the result exposed to the client.
*/
ret = dsdb_search_dn(ldb, mem_ctx, &acl_res, dn, acl_attrs,
DSDB_FLAG_AS_SYSTEM | DSDB_SEARCH_SHOW_RECYCLED);
if (ret != LDB_SUCCESS) {
DEBUG(10,("access_check: failed to find object %s\n", ldb_dn_get_linearized(dn)));
return ret;
}
return dsdb_check_access_on_dn_internal(ldb, acl_res,
mem_ctx,
token,
dn,
access_mask,
ext_right ? &guid : NULL);
}
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