/*
   Unix SMB/CIFS implementation.
   Copyright (C) Andrew Tridgell 1992-2001
   Copyright (C) Andrew Bartlett      2002
   Copyright (C) Rafal Szczesniak     2002
   Copyright (C) Tim Potter           2001

   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/>.
*/

/* the Samba secrets database stores any generated, private information
   such as the local SID and machine trust password */

#include "includes.h"
#include "passdb.h"
#include "../libcli/auth/libcli_auth.h"
#include "secrets.h"
#include "dbwrap/dbwrap.h"
#include "../librpc/ndr/libndr.h"
#include "util_tdb.h"
#include "libcli/security/security.h"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_PASSDB

static char *des_salt_key(const char *realm);

/**
 * Form a key for fetching the domain sid
 *
 * @param domain domain name
 *
 * @return keystring
 **/
static const char *domain_sid_keystr(const char *domain)
{
	char *keystr;

	keystr = talloc_asprintf_strupper_m(talloc_tos(), "%s/%s",
					    SECRETS_DOMAIN_SID, domain);
	SMB_ASSERT(keystr != NULL);
	return keystr;
}

static const char *domain_guid_keystr(const char *domain)
{
	char *keystr;

	keystr = talloc_asprintf_strupper_m(talloc_tos(), "%s/%s",
					    SECRETS_DOMAIN_GUID, domain);
	SMB_ASSERT(keystr != NULL);
	return keystr;
}

static const char *protect_ids_keystr(const char *domain)
{
	char *keystr;

	keystr = talloc_asprintf_strupper_m(talloc_tos(), "%s/%s",
					    SECRETS_PROTECT_IDS, domain);
	SMB_ASSERT(keystr != NULL);
	return keystr;
}

/* N O T E: never use this outside of passdb modules that store the SID on their own */
bool secrets_mark_domain_protected(const char *domain)
{
	bool ret;

	ret = secrets_store(protect_ids_keystr(domain), "TRUE", 5);
	if (!ret) {
		DEBUG(0, ("Failed to protect the Domain IDs\n"));
	}
	return ret;
}

bool secrets_clear_domain_protection(const char *domain)
{
	bool ret;
	void *protection = secrets_fetch(protect_ids_keystr(domain), NULL);
	
	if (protection) {
		SAFE_FREE(protection);
		ret = secrets_delete_entry(protect_ids_keystr(domain));
		if (!ret) {
			DEBUG(0, ("Failed to remove Domain IDs protection\n"));
		}
		return ret;
	}
	return true;
}

bool secrets_store_domain_sid(const char *domain, const struct dom_sid  *sid)
{
	char *protect_ids;
	bool ret;

	protect_ids = secrets_fetch(protect_ids_keystr(domain), NULL);
	if (protect_ids) {
		if (strncmp(protect_ids, "TRUE", 4)) {
			DEBUG(0, ("Refusing to store a Domain SID, "
				  "it has been marked as protected!\n"));
			SAFE_FREE(protect_ids);
			return false;
		}
	}
	SAFE_FREE(protect_ids);

	ret = secrets_store(domain_sid_keystr(domain), sid, sizeof(struct dom_sid ));

	/* Force a re-query, in the case where we modified our domain */
	if (ret) {
		if (dom_sid_equal(get_global_sam_sid(), sid) == false) {
			reset_global_sam_sid();
		}
	}
	return ret;
}

bool secrets_fetch_domain_sid(const char *domain, struct dom_sid  *sid)
{
	struct dom_sid  *dyn_sid;
	size_t size = 0;

	dyn_sid = (struct dom_sid  *)secrets_fetch(domain_sid_keystr(domain), &size);

	if (dyn_sid == NULL)
		return False;

	if (size != sizeof(struct dom_sid)) {
		SAFE_FREE(dyn_sid);
		return False;
	}

	*sid = *dyn_sid;
	SAFE_FREE(dyn_sid);
	return True;
}

bool secrets_store_domain_guid(const char *domain, const struct GUID *guid)
{
	char *protect_ids;
	const char *key;

	protect_ids = secrets_fetch(protect_ids_keystr(domain), NULL);
	if (protect_ids) {
		if (strncmp(protect_ids, "TRUE", 4)) {
			DEBUG(0, ("Refusing to store a Domain SID, "
				  "it has been marked as protected!\n"));
			SAFE_FREE(protect_ids);
			return false;
		}
	}
	SAFE_FREE(protect_ids);

	key = domain_guid_keystr(domain);
	return secrets_store(key, guid, sizeof(struct GUID));
}

bool secrets_fetch_domain_guid(const char *domain, struct GUID *guid)
{
	struct GUID *dyn_guid;
	const char *key;
	size_t size = 0;
	struct GUID new_guid;

	key = domain_guid_keystr(domain);
	dyn_guid = (struct GUID *)secrets_fetch(key, &size);

	if (!dyn_guid) {
		if (lp_server_role() == ROLE_DOMAIN_PDC) {
			new_guid = GUID_random();
			if (!secrets_store_domain_guid(domain, &new_guid))
				return False;
			dyn_guid = (struct GUID *)secrets_fetch(key, &size);
		}
		if (dyn_guid == NULL) {
			return False;
		}
	}

	if (size != sizeof(struct GUID)) {
		DEBUG(1,("UUID size %d is wrong!\n", (int)size));
		SAFE_FREE(dyn_guid);
		return False;
	}

	*guid = *dyn_guid;
	SAFE_FREE(dyn_guid);
	return True;
}

/**
 * Form a key for fetching the machine trust account sec channel type
 *
 * @param domain domain name
 *
 * @return keystring
 **/
static const char *machine_sec_channel_type_keystr(const char *domain)
{
	char *keystr;

	keystr = talloc_asprintf_strupper_m(talloc_tos(), "%s/%s",
					    SECRETS_MACHINE_SEC_CHANNEL_TYPE,
					    domain);
	SMB_ASSERT(keystr != NULL);
	return keystr;
}

/**
 * Form a key for fetching the machine trust account last change time
 *
 * @param domain domain name
 *
 * @return keystring
 **/
static const char *machine_last_change_time_keystr(const char *domain)
{
	char *keystr;

	keystr = talloc_asprintf_strupper_m(talloc_tos(), "%s/%s",
					    SECRETS_MACHINE_LAST_CHANGE_TIME,
					    domain);
	SMB_ASSERT(keystr != NULL);
	return keystr;
}


/**
 * Form a key for fetching the machine previous trust account password
 *
 * @param domain domain name
 *
 * @return keystring
 **/
static const char *machine_prev_password_keystr(const char *domain)
{
	char *keystr;

	keystr = talloc_asprintf_strupper_m(talloc_tos(), "%s/%s",
					    SECRETS_MACHINE_PASSWORD_PREV, domain);
	SMB_ASSERT(keystr != NULL);
	return keystr;
}

/**
 * Form a key for fetching the machine trust account password
 *
 * @param domain domain name
 *
 * @return keystring
 **/
static const char *machine_password_keystr(const char *domain)
{
	char *keystr;

	keystr = talloc_asprintf_strupper_m(talloc_tos(), "%s/%s",
					    SECRETS_MACHINE_PASSWORD, domain);
	SMB_ASSERT(keystr != NULL);
	return keystr;
}

/**
 * Form a key for fetching the machine trust account password
 *
 * @param domain domain name
 *
 * @return stored password's key
 **/
static const char *trust_keystr(const char *domain)
{
	char *keystr;

	keystr = talloc_asprintf_strupper_m(talloc_tos(), "%s/%s",
					    SECRETS_MACHINE_ACCT_PASS, domain);
	SMB_ASSERT(keystr != NULL);
	return keystr;
}

/************************************************************************
 Routine to get the default secure channel type for trust accounts
************************************************************************/

enum netr_SchannelType get_default_sec_channel(void)
{
	if (lp_server_role() == ROLE_DOMAIN_BDC ||
	    lp_server_role() == ROLE_DOMAIN_PDC ||
	    lp_server_role() == ROLE_ACTIVE_DIRECTORY_DC) {
		return SEC_CHAN_BDC;
	} else {
		return SEC_CHAN_WKSTA;
	}
}

/************************************************************************
 Routine to get the trust account password for a domain.
 This only tries to get the legacy hashed version of the password.
 The user of this function must have locked the trust password file using
 the above secrets_lock_trust_account_password().
************************************************************************/

bool secrets_fetch_trust_account_password_legacy(const char *domain,
						 uint8_t ret_pwd[16],
						 time_t *pass_last_set_time,
						 enum netr_SchannelType *channel)
{
	struct machine_acct_pass *pass;
	size_t size = 0;

	if (!(pass = (struct machine_acct_pass *)secrets_fetch(
		      trust_keystr(domain), &size))) {
		DEBUG(5, ("secrets_fetch failed!\n"));
		return False;
	}

	if (size != sizeof(*pass)) {
		DEBUG(0, ("secrets were of incorrect size!\n"));
		SAFE_FREE(pass);
		return False;
	}

	if (pass_last_set_time) {
		*pass_last_set_time = pass->mod_time;
	}
	memcpy(ret_pwd, pass->hash, 16);

	if (channel) {
		*channel = get_default_sec_channel();
	}

	SAFE_FREE(pass);
	return True;
}

/************************************************************************
 Routine to get the trust account password for a domain.
 The user of this function must have locked the trust password file using
 the above secrets_lock_trust_account_password().
************************************************************************/

bool secrets_fetch_trust_account_password(const char *domain, uint8_t ret_pwd[16],
					  time_t *pass_last_set_time,
					  enum netr_SchannelType *channel)
{
	char *plaintext;

	plaintext = secrets_fetch_machine_password(domain, pass_last_set_time,
						   channel);
	if (plaintext) {
		DEBUG(4,("Using cleartext machine password\n"));
		E_md4hash(plaintext, ret_pwd);
		SAFE_FREE(plaintext);
		return True;
	}

	return secrets_fetch_trust_account_password_legacy(domain, ret_pwd,
							   pass_last_set_time,
							   channel);
}

/************************************************************************
 Routine to delete all information related to the domain joined machine.
************************************************************************/

bool secrets_delete_machine_password_ex(const char *domain, const char *realm)
{
	const char *tmpkey = NULL;
	bool ok;

	if (realm != NULL) {
		tmpkey = des_salt_key(domain);
		ok = secrets_delete(tmpkey);
		if (!ok) {
			return false;
		}
	}

	tmpkey = domain_guid_keystr(domain);
	ok = secrets_delete(tmpkey);
	if (!ok) {
		return false;
	}

	tmpkey = machine_prev_password_keystr(domain);
	ok = secrets_delete(tmpkey);
	if (!ok) {
		return false;
	}

	tmpkey = machine_password_keystr(domain);
	ok = secrets_delete_entry(tmpkey);
	if (!ok) {
		return false;
	}

	tmpkey = machine_sec_channel_type_keystr(domain);
	ok = secrets_delete_entry(tmpkey);
	if (!ok) {
		return false;
	}

	tmpkey = machine_last_change_time_keystr(domain);
	ok = secrets_delete_entry(tmpkey);
	if (!ok) {
		return false;
	}

	tmpkey = domain_sid_keystr(domain);
	ok = secrets_delete_entry(tmpkey);
	if (!ok) {
		return false;
	}

	return true;
}

/************************************************************************
 Routine to delete the domain sid
************************************************************************/

bool secrets_delete_domain_sid(const char *domain)
{
	return secrets_delete_entry(domain_sid_keystr(domain));
}

/************************************************************************
 Routine to store the previous machine password (by storing the current password
 as the old)
************************************************************************/

static bool secrets_store_prev_machine_password(const char *domain)
{
	char *oldpass;
	bool ret;

	oldpass = (char *)secrets_fetch(machine_password_keystr(domain), NULL);
	if (oldpass == NULL) {
		return true;
	}
	ret = secrets_store(machine_prev_password_keystr(domain), oldpass, strlen(oldpass)+1);
	SAFE_FREE(oldpass);
	return ret;
}

/************************************************************************
 Routine to set the plaintext machine account password for a realm
 the password is assumed to be a null terminated ascii string.
 Before storing
************************************************************************/

bool secrets_store_machine_password(const char *pass, const char *domain,
				    enum netr_SchannelType sec_channel)
{
	bool ret;
	uint32_t last_change_time;
	uint32_t sec_channel_type;

	if (!secrets_store_prev_machine_password(domain)) {
		return false;
	}

	ret = secrets_store(machine_password_keystr(domain), pass, strlen(pass)+1);
	if (!ret)
		return ret;

	SIVAL(&last_change_time, 0, time(NULL));
	ret = secrets_store(machine_last_change_time_keystr(domain), &last_change_time, sizeof(last_change_time));

	SIVAL(&sec_channel_type, 0, sec_channel);
	ret = secrets_store(machine_sec_channel_type_keystr(domain), &sec_channel_type, sizeof(sec_channel_type));

	return ret;
}

/************************************************************************
 Set the machine trust account password, the old pw and last change
 time, domain SID and salting principals based on values passed in
 (added to supprt the secrets_tdb_sync module on secrets.ldb)
************************************************************************/

bool secrets_store_machine_pw_sync(const char *pass, const char *oldpass, const char *domain,
				   const char *realm,
				   const char *salting_principal, uint32_t supported_enc_types,
				   const struct dom_sid *domain_sid, uint32_t last_change_time,
				   uint32_t secure_channel_type,
				   bool delete_join)
{
	bool ret;
	uint8_t last_change_time_store[4];
	TALLOC_CTX *frame = talloc_stackframe();
	uint8_t sec_channel_bytes[4];

	if (delete_join) {
		secrets_delete_machine_password_ex(domain, realm);
		TALLOC_FREE(frame);
		return true;
	}

	ret = secrets_store(machine_password_keystr(domain), pass, strlen(pass)+1);
	if (!ret) {
		TALLOC_FREE(frame);
		return ret;
	}

	if (oldpass) {
		ret = secrets_store(machine_prev_password_keystr(domain), oldpass, strlen(oldpass)+1);
	} else {
		ret = secrets_delete(machine_prev_password_keystr(domain));
	}
	if (!ret) {
		TALLOC_FREE(frame);
		return ret;
	}

	if (secure_channel_type == 0) {
		/* We delete this and instead have the read code fall back to
		 * a default based on server role, as our caller can't specify
		 * this with any more certainty */
		ret = secrets_delete(machine_sec_channel_type_keystr(domain));
		if (!ret) {
			TALLOC_FREE(frame);
			return ret;
		}
	} else {
		SIVAL(&sec_channel_bytes, 0, secure_channel_type);
		ret = secrets_store(machine_sec_channel_type_keystr(domain), 
				    &sec_channel_bytes, sizeof(sec_channel_bytes));
		if (!ret) {
			TALLOC_FREE(frame);
			return ret;
		}
	}

	SIVAL(&last_change_time_store, 0, last_change_time);
	ret = secrets_store(machine_last_change_time_keystr(domain),
			    &last_change_time_store, sizeof(last_change_time));

	if (!ret) {
		TALLOC_FREE(frame);
		return ret;
	}

	ret = secrets_store_domain_sid(domain, domain_sid);

	if (!ret) {
		TALLOC_FREE(frame);
		return ret;
	}

	if (realm != NULL) {
		char *key = des_salt_key(realm);

		if (salting_principal != NULL) {
			ret = secrets_store(key,
					    salting_principal,
					    strlen(salting_principal)+1);
		} else {
			ret = secrets_delete(key);
		}
	}

	TALLOC_FREE(frame);
	return ret;
}

/************************************************************************
 Return the standard DES salt key
************************************************************************/

char* kerberos_standard_des_salt( void )
{
	fstring salt;

	fstr_sprintf( salt, "host/%s.%s@", lp_netbios_name(), lp_realm() );
	(void)strlower_m( salt );
	fstrcat( salt, lp_realm() );

	return SMB_STRDUP( salt );
}

/************************************************************************
************************************************************************/

static char *des_salt_key(const char *realm)
{
	char *keystr;

	keystr = talloc_asprintf_strupper_m(talloc_tos(), "%s/DES/%s",
					    SECRETS_SALTING_PRINCIPAL,
					    realm);
	SMB_ASSERT(keystr != NULL);
	return keystr;
}

/************************************************************************
************************************************************************/

bool kerberos_secrets_store_des_salt( const char* salt )
{
	char* key;
	bool ret;

	key = des_salt_key(lp_realm());
	if (key == NULL) {
		DEBUG(0,("kerberos_secrets_store_des_salt: failed to generate key!\n"));
		return False;
	}

	if ( !salt ) {
		DEBUG(8,("kerberos_secrets_store_des_salt: deleting salt\n"));
		secrets_delete_entry( key );
		return True;
	}

	DEBUG(3,("kerberos_secrets_store_des_salt: Storing salt \"%s\"\n", salt));

	ret = secrets_store( key, salt, strlen(salt)+1 );

	TALLOC_FREE(key);

	return ret;
}

/************************************************************************
************************************************************************/

static
char* kerberos_secrets_fetch_des_salt( void )
{
	char *salt, *key;

	key = des_salt_key(lp_realm());
	if (key == NULL) {
		DEBUG(0,("kerberos_secrets_fetch_des_salt: failed to generate key!\n"));
		return NULL;
	}

	salt = (char*)secrets_fetch( key, NULL );

	TALLOC_FREE(key);

	return salt;
}

/************************************************************************
 Routine to get the salting principal for this service.
 Caller must free if return is not null.
 ************************************************************************/

char *kerberos_secrets_fetch_salt_princ(void)
{
	char *salt_princ_s;
	/* lookup new key first */

	salt_princ_s = kerberos_secrets_fetch_des_salt();
	if (salt_princ_s == NULL) {
		/* fall back to host/machine.realm@REALM */
		salt_princ_s = kerberos_standard_des_salt();
	}

	return salt_princ_s;
}

/************************************************************************
 Routine to fetch the previous plaintext machine account password for a realm
 the password is assumed to be a null terminated ascii string.
************************************************************************/

char *secrets_fetch_prev_machine_password(const char *domain)
{
	return (char *)secrets_fetch(machine_prev_password_keystr(domain), NULL);
}

/************************************************************************
 Routine to fetch the last change time of the machine account password
  for a realm
************************************************************************/

time_t secrets_fetch_pass_last_set_time(const char *domain)
{
	uint32_t *last_set_time;
	time_t pass_last_set_time;

	last_set_time = secrets_fetch(machine_last_change_time_keystr(domain),
				      NULL);
	if (last_set_time) {
		pass_last_set_time = IVAL(last_set_time,0);
		SAFE_FREE(last_set_time);
	} else {
		pass_last_set_time = 0;
	}

	return pass_last_set_time;
}

/************************************************************************
 Routine to fetch the plaintext machine account password for a realm
 the password is assumed to be a null terminated ascii string.
************************************************************************/

char *secrets_fetch_machine_password(const char *domain,
				     time_t *pass_last_set_time,
				     enum netr_SchannelType *channel)
{
	char *ret;
	ret = (char *)secrets_fetch(machine_password_keystr(domain), NULL);

	if (pass_last_set_time) {
		*pass_last_set_time = secrets_fetch_pass_last_set_time(domain);
	}

	if (channel) {
		size_t size;
		uint32_t *channel_type;
		channel_type = (unsigned int *)secrets_fetch(machine_sec_channel_type_keystr(domain), &size);
		if (channel_type) {
			*channel = IVAL(channel_type,0);
			SAFE_FREE(channel_type);
		} else {
			*channel = get_default_sec_channel();
		}
	}

	return ret;
}