/*
   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 "system/filesys.h"
#include "../libcli/auth/libcli_auth.h"
#include "librpc/gen_ndr/ndr_secrets.h"
#include "secrets.h"
#include "dbwrap/dbwrap.h"
#include "dbwrap/dbwrap_open.h"
#include "../libcli/security/security.h"
#include "util_tdb.h"
#include "auth/credentials/credentials.h"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_PASSDB

static struct db_context *db_ctx;

/* open up the secrets database with specified private_dir path */
bool secrets_init_path(const char *private_dir)
{
	char *fname = NULL;
	TALLOC_CTX *frame;

	if (db_ctx != NULL) {
		return True;
	}

	if (private_dir == NULL) {
		return False;
	}

	frame = talloc_stackframe();
	fname = talloc_asprintf(frame, "%s/secrets.tdb", private_dir);
	if (fname == NULL) {
		TALLOC_FREE(frame);
		return False;
	}

	db_ctx = db_open(NULL, fname, 0,
			 TDB_DEFAULT, O_RDWR|O_CREAT, 0600,
			 DBWRAP_LOCK_ORDER_1, DBWRAP_FLAG_NONE);

	if (db_ctx == NULL) {
		DEBUG(0,("Failed to open %s\n", fname));
		TALLOC_FREE(frame);
		return False;
	}

	TALLOC_FREE(frame);
	return True;
}

/* open up the secrets database */
bool secrets_init(void)
{
	return secrets_init_path(lp_private_dir());
}

struct db_context *secrets_db_ctx(void)
{
	if (!secrets_init()) {
		return NULL;
	}

	return db_ctx;
}

/*
 * close secrets.tdb
 */
void secrets_shutdown(void)
{
	TALLOC_FREE(db_ctx);
}

/* read a entry from the secrets database - the caller must free the result
   if size is non-null then the size of the entry is put in there
 */
void *secrets_fetch(const char *key, size_t *size)
{
	TDB_DATA dbuf;
	void *result;
	NTSTATUS status;

	if (!secrets_init()) {
		return NULL;
	}

	status = dbwrap_fetch(db_ctx, talloc_tos(), string_tdb_data(key),
			      &dbuf);
	if (!NT_STATUS_IS_OK(status)) {
		return NULL;
	}

	result = smb_memdup(dbuf.dptr, dbuf.dsize);
	if (result == NULL) {
		return NULL;
	}
	/*
	 * secrets_fetch() is a generic code and may be used for sensitive data,
	 * so clear the local dbuf.dptr memory via BURN_PTR_SIZE().
	 * The future plan is to convert secrets_fetch() to talloc.
	 * That would improve performance via:
	 * - avoid smb_memdup() above, instead directly return dbuf.dptr
	 * - BURN_PTR_SIZE() will be done not here but in the caller and only
	 *   if the caller asks for sensitive data.
	 */
	BURN_PTR_SIZE(dbuf.dptr, dbuf.dsize);
	TALLOC_FREE(dbuf.dptr);

	if (size) {
		*size = dbuf.dsize;
	}

	return result;
}

/* store a secrets entry
 */
bool secrets_store(const char *key, const void *data, size_t size)
{
	NTSTATUS status;

	if (!secrets_init()) {
		return false;
	}

	status = dbwrap_trans_store(db_ctx, string_tdb_data(key),
				    make_tdb_data((const uint8_t *)data, size),
				    TDB_REPLACE);
	return NT_STATUS_IS_OK(status);
}

bool secrets_store_creds(struct cli_credentials *creds)
{
	const char *p = NULL;
	bool ok;

	p = cli_credentials_get_username(creds);
	if (p == NULL) {
		return false;
	}

	ok = secrets_store(SECRETS_AUTH_USER, p, strlen(p) + 1);
	if (!ok) {
		DBG_ERR("Failed storing auth user name\n");
		return false;
	}


	p = cli_credentials_get_domain(creds);
	if (p == NULL) {
		return false;
	}

	ok = secrets_store(SECRETS_AUTH_DOMAIN, p, strlen(p) + 1);
	if (!ok) {
		DBG_ERR("Failed storing auth domain name\n");
		return false;
	}


	p = cli_credentials_get_password(creds);
	if (p == NULL) {
		return false;
	}

	ok = secrets_store(SECRETS_AUTH_PASSWORD, p, strlen(p) + 1);
	if (!ok) {
		DBG_ERR("Failed storing auth password\n");
		return false;
	}

	return true;
}


/* delete a secets database entry
 */
bool secrets_delete_entry(const char *key)
{
	NTSTATUS status;
	if (!secrets_init()) {
		return false;
	}

	status = dbwrap_trans_delete(db_ctx, string_tdb_data(key));

	return NT_STATUS_IS_OK(status);
}

/*
 * Deletes the key if it exists.
 */
bool secrets_delete(const char *key)
{
	bool exists;

	if (!secrets_init()) {
		return false;
	}

	exists = dbwrap_exists(db_ctx, string_tdb_data(key));
	if (!exists) {
		return true;
	}

	return secrets_delete_entry(key);
}

/**
 * Form a key for fetching a trusted domain password
 *
 * @param domain trusted domain name
 *
 * @return stored password's key
 **/
static char *trustdom_keystr(const char *domain)
{
	char *keystr;

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

/************************************************************************
 Routine to get account password to trusted domain
************************************************************************/

bool secrets_fetch_trusted_domain_password(const char *domain, char** pwd,
                                           struct dom_sid *sid, time_t *pass_last_set_time)
{
	struct TRUSTED_DOM_PASS pass;
	enum ndr_err_code ndr_err;

	/* unpacking structures */
	DATA_BLOB blob;

	/* fetching trusted domain password structure */
	if (!(blob.data = (uint8_t *)secrets_fetch(trustdom_keystr(domain),
						   &blob.length))) {
		DEBUG(5, ("secrets_fetch failed!\n"));
		return False;
	}

	/* unpack trusted domain password */
	ndr_err = ndr_pull_struct_blob(&blob, talloc_tos(), &pass,
			(ndr_pull_flags_fn_t)ndr_pull_TRUSTED_DOM_PASS);

	/* This blob is NOT talloc based! */
	BURN_FREE(blob.data, blob.length);

	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
		return false;
	}

	if (pass.pass != NULL) {
		talloc_keep_secret(discard_const_p(char, pass.pass));
	}

	/* the trust's password */
	if (pwd) {
		*pwd = SMB_STRDUP(pass.pass);
		if (!*pwd) {
			return False;
		}
	}

	/* last change time */
	if (pass_last_set_time) *pass_last_set_time = pass.mod_time;

	/* domain sid */
	if (sid != NULL) sid_copy(sid, &pass.domain_sid);

	return True;
}

/**
 * Routine to store the password for trusted domain
 *
 * @param domain remote domain name
 * @param pwd plain text password of trust relationship
 * @param sid remote domain sid
 *
 * @return true if succeeded
 **/

bool secrets_store_trusted_domain_password(const char* domain, const char* pwd,
                                           const struct dom_sid *sid)
{
	bool ret;

	/* packing structures */
	DATA_BLOB blob;
	enum ndr_err_code ndr_err;
	struct TRUSTED_DOM_PASS pass;
	ZERO_STRUCT(pass);

	pass.uni_name = domain;
	pass.uni_name_len = strlen(domain)+1;

	/* last change time */
	pass.mod_time = time(NULL);

	/* password of the trust */
	pass.pass_len = strlen(pwd);
	pass.pass = pwd;

	/* domain sid */
	sid_copy(&pass.domain_sid, sid);

	ndr_err = ndr_push_struct_blob(&blob, talloc_tos(), &pass,
			(ndr_push_flags_fn_t)ndr_push_TRUSTED_DOM_PASS);
	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
		return false;
	}

	ret = secrets_store(trustdom_keystr(domain), blob.data, blob.length);

	/* This blob is talloc based. */
	data_blob_clear_free(&blob);

	return ret;
}

/************************************************************************
 Routine to delete the password for trusted domain
************************************************************************/

bool trusted_domain_password_delete(const char *domain)
{
	return secrets_delete_entry(trustdom_keystr(domain));
}

bool secrets_store_ldap_pw(const char* dn, char* pw)
{
	char *key = NULL;
	bool ret;

	if (asprintf(&key, "%s/%s", SECRETS_LDAP_BIND_PW, dn) < 0) {
		DEBUG(0, ("secrets_store_ldap_pw: asprintf failed!\n"));
		return False;
	}

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

	SAFE_FREE(key);
	return ret;
}

/*******************************************************************
 Find the ldap password.
******************************************************************/

bool fetch_ldap_pw(char **dn, char** pw)
{
	char *key = NULL;
	size_t size = 0;

	*dn = smb_xstrdup(lp_ldap_admin_dn());

	if (asprintf(&key, "%s/%s", SECRETS_LDAP_BIND_PW, *dn) < 0) {
		SAFE_FREE(*dn);
		DEBUG(0, ("fetch_ldap_pw: asprintf failed!\n"));
		return false;
	}

	*pw=(char *)secrets_fetch(key, &size);
	SAFE_FREE(key);

	if (*pw == NULL || size == 0 || (*pw)[size-1] != '\0') {
		DBG_ERR("No valid password for %s\n", *dn);
		BURN_FREE_STR(*pw);
		SAFE_FREE(*dn);
		return false;
	}

	return true;
}

/*******************************************************************************
 Store a complete AFS keyfile into secrets.tdb.
*******************************************************************************/

bool secrets_store_afs_keyfile(const char *cell, const struct afs_keyfile *keyfile)
{
	fstring key;

	if ((cell == NULL) || (keyfile == NULL))
		return False;

	if (ntohl(keyfile->nkeys) > SECRETS_AFS_MAXKEYS)
		return False;

	slprintf(key, sizeof(key)-1, "%s/%s", SECRETS_AFS_KEYFILE, cell);
	return secrets_store(key, keyfile, sizeof(struct afs_keyfile));
}

/*******************************************************************************
 Fetch the current (highest) AFS key from secrets.tdb
*******************************************************************************/
bool secrets_fetch_afs_key(const char *cell, struct afs_key *result)
{
	fstring key;
	struct afs_keyfile *keyfile;
	size_t size = 0;
	uint32_t i;

	slprintf(key, sizeof(key)-1, "%s/%s", SECRETS_AFS_KEYFILE, cell);

	keyfile = (struct afs_keyfile *)secrets_fetch(key, &size);

	if (keyfile == NULL)
		return False;

	if (size != sizeof(struct afs_keyfile)) {
		BURN_FREE(keyfile, sizeof(*keyfile));
		return False;
	}

	i = ntohl(keyfile->nkeys);

	if (i > SECRETS_AFS_MAXKEYS) {
		BURN_FREE(keyfile, sizeof(*keyfile));
		return False;
	}

	*result = keyfile->entry[i-1];

	result->kvno = ntohl(result->kvno);

	BURN_FREE(keyfile, sizeof(*keyfile));

	return True;
}

/******************************************************************************
  When kerberos is not available, choose between anonymous or
  authenticated connections.

  We need to use an authenticated connection if DCs have the
  RestrictAnonymous registry entry set > 0, or the "Additional
  restrictions for anonymous connections" set in the win2k Local
  Security Policy.

  Caller to free() result in domain, username, password
*******************************************************************************/
void secrets_fetch_ipc_userpass(char **username, char **domain, char **password)
{
	*username = (char *)secrets_fetch(SECRETS_AUTH_USER, NULL);
	*domain = (char *)secrets_fetch(SECRETS_AUTH_DOMAIN, NULL);
	*password = (char *)secrets_fetch(SECRETS_AUTH_PASSWORD, NULL);

	if (*username && **username) {

		if (!*domain || !**domain) {
			SAFE_FREE(*domain);
			*domain = smb_xstrdup(lp_workgroup());
		}

		if (!*password || !**password) {
			BURN_FREE_STR(*password);
			*password = smb_xstrdup("");
		}

		DEBUG(3, ("IPC$ connections done by user %s\\%s\n",
			  *domain, *username));

	} else {
		DEBUG(3, ("IPC$ connections done anonymously\n"));
		SAFE_FREE(*username);
		SAFE_FREE(*domain);
		BURN_FREE_STR(*password);
		*username = smb_xstrdup("");
		*domain = smb_xstrdup("");
		*password = smb_xstrdup("");
	}
}

bool secrets_store_generic(const char *owner, const char *key, const char *secret)
{
	char *tdbkey = NULL;
	bool ret;

	if (asprintf(&tdbkey, "SECRETS/GENERIC/%s/%s", owner, key) < 0) {
		DEBUG(0, ("asprintf failed!\n"));
		return False;
	}

	ret = secrets_store(tdbkey, secret, strlen(secret)+1);

	SAFE_FREE(tdbkey);
	return ret;
}

/*******************************************************************
 Find the ldap password.
******************************************************************/

char *secrets_fetch_generic(const char *owner, const char *key)
{
	char *secret = NULL;
	char *tdbkey = NULL;

	if (( ! owner) || ( ! key)) {
		DEBUG(1, ("Invalid Parameters\n"));
		return NULL;
	}

	if (asprintf(&tdbkey, "SECRETS/GENERIC/%s/%s", owner, key) < 0) {
		DEBUG(0, ("Out of memory!\n"));
		return NULL;
	}

	secret = (char *)secrets_fetch(tdbkey, NULL);
	SAFE_FREE(tdbkey);

	return secret;
}