/* 
   Unix SMB/CIFS mplementation.
   Helper functions for applying replicated objects
   
   Copyright (C) Stefan Metzmacher <metze@samba.org> 2007
    
   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 "includes.h"
#include "dsdb/samdb/samdb.h"
#include "lib/ldb/include/ldb_errors.h"
#include "lib/util/dlinklist.h"
#include "librpc/gen_ndr/ndr_misc.h"
#include "librpc/gen_ndr/ndr_drsuapi.h"
#include "librpc/gen_ndr/ndr_drsblobs.h"
#include "lib/crypto/crypto.h"
#include "libcli/auth/libcli_auth.h"
#include "param/param.h"

static WERROR dsdb_decrypt_attribute_value(TALLOC_CTX *mem_ctx,
					   const DATA_BLOB *gensec_skey,
					   bool rid_crypt,
					   uint32_t rid,
					   DATA_BLOB *in,
					   DATA_BLOB *out)
{
	DATA_BLOB confounder;
	DATA_BLOB enc_buffer;

	struct MD5Context md5;
	uint8_t _enc_key[16];
	DATA_BLOB enc_key;

	DATA_BLOB dec_buffer;

	uint32_t crc32_given;
	uint32_t crc32_calc;
	DATA_BLOB checked_buffer;

	DATA_BLOB plain_buffer;

	/*
	 * users with rid == 0 should not exist
	 */
	if (rid_crypt && rid == 0) {
		return WERR_DS_DRA_INVALID_PARAMETER;
	}

	/* 
	 * the first 16 bytes at the beginning are the confounder
	 * followed by the 4 byte crc32 checksum
	 */
	if (in->length < 20) {
		return WERR_DS_DRA_INVALID_PARAMETER;
	}
	confounder = data_blob_const(in->data, 16);
	enc_buffer = data_blob_const(in->data + 16, in->length - 16);

	/* 
	 * build the encryption key md5 over the session key followed
	 * by the confounder
	 * 
	 * here the gensec session key is used and
	 * not the dcerpc ncacn_ip_tcp "SystemLibraryDTC" key!
	 */
	enc_key = data_blob_const(_enc_key, sizeof(_enc_key));
	MD5Init(&md5);
	MD5Update(&md5, gensec_skey->data, gensec_skey->length);
	MD5Update(&md5, confounder.data, confounder.length);
	MD5Final(enc_key.data, &md5);

	/*
	 * copy the encrypted buffer part and 
	 * decrypt it using the created encryption key using arcfour
	 */
	dec_buffer = data_blob_const(enc_buffer.data, enc_buffer.length);
	arcfour_crypt_blob(dec_buffer.data, dec_buffer.length, &enc_key);

	/* 
	 * the first 4 byte are the crc32 checksum
	 * of the remaining bytes
	 */
	crc32_given = IVAL(dec_buffer.data, 0);
	crc32_calc = crc32_calc_buffer(dec_buffer.data + 4 , dec_buffer.length - 4);
	if (crc32_given != crc32_calc) {
		return WERR_SEC_E_DECRYPT_FAILURE;
	}
	checked_buffer = data_blob_const(dec_buffer.data + 4, dec_buffer.length - 4);

	plain_buffer = data_blob_talloc(mem_ctx, checked_buffer.data, checked_buffer.length);
	W_ERROR_HAVE_NO_MEMORY(plain_buffer.data);

	/*
	 * The following rid_crypt obfuscation isn't session specific
	 * and not really needed here, because we allways know the rid of the
	 * user account.
	 *
	 * But for the rest of samba it's easier when we remove this static
	 * obfuscation here
	 */
	if (rid_crypt) {
		uint32_t i, num_hashes;

		if ((checked_buffer.length % 16) != 0) {
			return WERR_DS_DRA_INVALID_PARAMETER;
		}

		num_hashes = plain_buffer.length / 16;
		for (i = 0; i < num_hashes; i++) {
			uint32_t offset = i * 16;
			sam_rid_crypt(rid, checked_buffer.data + offset, plain_buffer.data + offset, 0);
		}
	}

	*out = plain_buffer;
	return WERR_OK;
}

static WERROR dsdb_decrypt_attribute(const DATA_BLOB *gensec_skey,
				     uint32_t rid,
				     struct drsuapi_DsReplicaAttribute *attr)
{
	WERROR status;
	TALLOC_CTX *mem_ctx;
	DATA_BLOB *enc_data;
	DATA_BLOB plain_data;
	bool rid_crypt = false;

	if (attr->value_ctr.num_values == 0) {
		return WERR_OK;
	}

	switch (attr->attid) {
	case DRSUAPI_ATTRIBUTE_dBCSPwd:
	case DRSUAPI_ATTRIBUTE_unicodePwd:
	case DRSUAPI_ATTRIBUTE_ntPwdHistory:
	case DRSUAPI_ATTRIBUTE_lmPwdHistory:
		rid_crypt = true;
		break;
	case DRSUAPI_ATTRIBUTE_supplementalCredentials:
	case DRSUAPI_ATTRIBUTE_priorValue:
	case DRSUAPI_ATTRIBUTE_currentValue:
	case DRSUAPI_ATTRIBUTE_trustAuthOutgoing:
	case DRSUAPI_ATTRIBUTE_trustAuthIncoming:
	case DRSUAPI_ATTRIBUTE_initialAuthOutgoing:
	case DRSUAPI_ATTRIBUTE_initialAuthIncoming:
		break;
	default:
		return WERR_OK;
	}

	if (attr->value_ctr.num_values > 1) {
		return WERR_DS_DRA_INVALID_PARAMETER;
	}

	if (!attr->value_ctr.values[0].blob) {
		return WERR_DS_DRA_INVALID_PARAMETER;
	}

	mem_ctx		= attr->value_ctr.values[0].blob;
	enc_data	= attr->value_ctr.values[0].blob;

	status = dsdb_decrypt_attribute_value(mem_ctx,
					      gensec_skey,
					      rid_crypt,
					      rid,
					      enc_data,
					      &plain_data);
	W_ERROR_NOT_OK_RETURN(status);

	talloc_free(attr->value_ctr.values[0].blob->data);
	*attr->value_ctr.values[0].blob = plain_data;

	return WERR_OK;
}

static WERROR dsdb_convert_object(struct ldb_context *ldb,
				  const struct dsdb_schema *schema,
				  struct dsdb_extended_replicated_objects *ctr,
				  const struct drsuapi_DsReplicaObjectListItemEx *in,
				  const DATA_BLOB *gensec_skey,
				  TALLOC_CTX *mem_ctx,
				  struct dsdb_extended_replicated_object *out)
{
	NTSTATUS nt_status;
	enum ndr_err_code ndr_err;
	WERROR status;
	uint32_t i;
	struct ldb_message *msg;
	struct replPropertyMetaDataBlob *md;
	struct ldb_val guid_value;
	NTTIME whenChanged = 0;
	time_t whenChanged_t;
	const char *whenChanged_s;
	const char *rdn_name = NULL;
	const struct ldb_val *rdn_value = NULL;
	const struct dsdb_attribute *rdn_attr = NULL;
	uint32_t rdn_attid;
	struct drsuapi_DsReplicaAttribute *name_a = NULL;
	struct drsuapi_DsReplicaMetaData *name_d = NULL;
	struct replPropertyMetaData1 *rdn_m = NULL;
	struct dom_sid *sid = NULL;
	uint32_t rid = 0;
	int ret;

	if (!in->object.identifier) {
		return WERR_FOOBAR;
	}

	if (!in->object.identifier->dn || !in->object.identifier->dn[0]) {
		return WERR_FOOBAR;
	}

	if (in->object.attribute_ctr.num_attributes != 0 && !in->meta_data_ctr) {
		return WERR_FOOBAR;
	}

	if (in->object.attribute_ctr.num_attributes != in->meta_data_ctr->count) {
		return WERR_FOOBAR;
	}

	sid = &in->object.identifier->sid;
	if (sid->num_auths > 0) {
		rid = sid->sub_auths[sid->num_auths - 1];
	}

	msg = ldb_msg_new(mem_ctx);
	W_ERROR_HAVE_NO_MEMORY(msg);

	msg->dn			= ldb_dn_new(msg, ldb, in->object.identifier->dn);
	W_ERROR_HAVE_NO_MEMORY(msg->dn);

	rdn_name	= ldb_dn_get_rdn_name(msg->dn);
	rdn_attr	= dsdb_attribute_by_lDAPDisplayName(schema, rdn_name);
	if (!rdn_attr) {
		return WERR_FOOBAR;
	}
	rdn_attid	= rdn_attr->attributeID_id;
	rdn_value	= ldb_dn_get_rdn_val(msg->dn);

	msg->num_elements	= in->object.attribute_ctr.num_attributes;
	msg->elements		= talloc_array(msg, struct ldb_message_element,
					       msg->num_elements);
	W_ERROR_HAVE_NO_MEMORY(msg->elements);

	md = talloc(mem_ctx, struct replPropertyMetaDataBlob);
	W_ERROR_HAVE_NO_MEMORY(md);

	md->version		= 1;
	md->reserved		= 0;
	md->ctr.ctr1.count	= in->meta_data_ctr->count;
	md->ctr.ctr1.reserved	= 0;
	md->ctr.ctr1.array	= talloc_array(mem_ctx,
					       struct replPropertyMetaData1,
					       md->ctr.ctr1.count + 1); /* +1 because of the RDN attribute */
	W_ERROR_HAVE_NO_MEMORY(md->ctr.ctr1.array);

	for (i=0; i < in->meta_data_ctr->count; i++) {
		struct drsuapi_DsReplicaAttribute *a;
		struct drsuapi_DsReplicaMetaData *d;
		struct replPropertyMetaData1 *m;
		struct ldb_message_element *e;

		a = &in->object.attribute_ctr.attributes[i];
		d = &in->meta_data_ctr->meta_data[i];
		m = &md->ctr.ctr1.array[i];
		e = &msg->elements[i];

		status = dsdb_decrypt_attribute(gensec_skey, rid, a);
		W_ERROR_NOT_OK_RETURN(status);

		status = dsdb_attribute_drsuapi_to_ldb(schema, a, msg->elements, e);
		W_ERROR_NOT_OK_RETURN(status);

		m->attid			= a->attid;
		m->version			= d->version;
		m->originating_change_time	= d->originating_change_time;
		m->originating_invocation_id	= d->originating_invocation_id;
		m->originating_usn		= d->originating_usn;
		m->local_usn			= 0;

		if (d->originating_change_time > whenChanged) {
			whenChanged = d->originating_change_time;
		}

		if (a->attid == DRSUAPI_ATTRIBUTE_name) {
			name_a = a;
			name_d = d;
			rdn_m = &md->ctr.ctr1.array[md->ctr.ctr1.count];
		}
	}

	if (rdn_m) {
		ret = ldb_msg_add_value(msg, rdn_attr->lDAPDisplayName, rdn_value, NULL);
		if (ret != LDB_SUCCESS) {
			return WERR_FOOBAR;
		}

		rdn_m->attid				= rdn_attid;
		rdn_m->version				= name_d->version;
		rdn_m->originating_change_time		= name_d->originating_change_time;
		rdn_m->originating_invocation_id	= name_d->originating_invocation_id;
		rdn_m->originating_usn			= name_d->originating_usn;
		rdn_m->local_usn			= 0;
		md->ctr.ctr1.count++;

	}

	whenChanged_t = nt_time_to_unix(whenChanged);
	whenChanged_s = ldb_timestring(msg, whenChanged_t);
	W_ERROR_HAVE_NO_MEMORY(whenChanged_s);

	ndr_err = ndr_push_struct_blob(&guid_value, msg, 
				       lp_iconv_convenience(ldb_get_opaque(ldb, "loadparm")),
				       &in->object.identifier->guid,
					 (ndr_push_flags_fn_t)ndr_push_GUID);
	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
		nt_status = ndr_map_error2ntstatus(ndr_err);
		return ntstatus_to_werror(nt_status);
	}

	out->msg		= msg;
	out->guid_value		= guid_value;
	out->when_changed	= whenChanged_s;
	out->meta_data		= md;
	return WERR_OK;
}

WERROR dsdb_extended_replicated_objects_commit(struct ldb_context *ldb,
					       const char *partition_dn,
					       const struct drsuapi_DsReplicaOIDMapping_Ctr *mapping_ctr,
					       uint32_t object_count,
					       const struct drsuapi_DsReplicaObjectListItemEx *first_object,
					       uint32_t linked_attributes_count,
					       const struct drsuapi_DsReplicaLinkedAttribute *linked_attributes,
					       const struct repsFromTo1 *source_dsa,
					       const struct drsuapi_DsReplicaCursor2CtrEx *uptodateness_vector,
					       const DATA_BLOB *gensec_skey,
					       TALLOC_CTX *mem_ctx,
					       struct dsdb_extended_replicated_objects **_out)
{
	WERROR status;
	const struct dsdb_schema *schema;
	struct dsdb_extended_replicated_objects *out;
	struct ldb_result *ext_res;
	const struct drsuapi_DsReplicaObjectListItemEx *cur;
	uint32_t i;
	int ret;

	schema = dsdb_get_schema(ldb);
	if (!schema) {
		return WERR_DS_SCHEMA_NOT_LOADED;
	}

	status = dsdb_verify_oid_mappings_drsuapi(schema, mapping_ctr);
	W_ERROR_NOT_OK_RETURN(status);

	out = talloc_zero(mem_ctx, struct dsdb_extended_replicated_objects);
	W_ERROR_HAVE_NO_MEMORY(out);
	out->version		= DSDB_EXTENDED_REPLICATED_OBJECTS_VERSION;

	out->partition_dn	= ldb_dn_new(out, ldb, partition_dn);
	W_ERROR_HAVE_NO_MEMORY(out->partition_dn);

	out->source_dsa		= source_dsa;
	out->uptodateness_vector= uptodateness_vector;

	out->num_objects	= object_count;
	out->objects		= talloc_array(out,
					       struct dsdb_extended_replicated_object,
					       out->num_objects);
	W_ERROR_HAVE_NO_MEMORY(out->objects);

	for (i=0, cur = first_object; cur; cur = cur->next_object, i++) {
		if (i == out->num_objects) {
			return WERR_FOOBAR;
		}

		status = dsdb_convert_object(ldb, schema, out, cur, gensec_skey, out->objects, &out->objects[i]);
		W_ERROR_NOT_OK_RETURN(status);
	}
	if (i != out->num_objects) {
		return WERR_FOOBAR;
	}

	/* TODO: handle linked attributes */

	ret = ldb_extended(ldb, DSDB_EXTENDED_REPLICATED_OBJECTS_OID, out, &ext_res);
	if (ret != LDB_SUCCESS) {
		DEBUG(0,("Failed to apply records: %s: %s\n",
			 ldb_errstring(ldb), ldb_strerror(ret)));
		talloc_free(out);
		return WERR_FOOBAR;
	}
	talloc_free(ext_res);

	if (_out) {
		*_out = out;
	} else {
		talloc_free(out);
	}

	return WERR_OK;
}
