/*

 *  Unix SMB/CIFS implementation.

 *  account policy storage

 *  Copyright (C) Jean François Micouleau      1998-2001

 *  Copyright (C) Andrew Bartlett              2002

 *  Copyright (C) Guenther Deschner            2004-2005

 *

 *  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 "system/filesys.h"

#include "passdb.h"

#include "dbwrap/dbwrap.h"

#include "dbwrap/dbwrap_open.h"

#include "../libcli/security/security.h"

#include "lib/privileges.h"

#include "lib/gencache.h"

#include "lib/util/smb_strtox.h"

static struct db_context *db;

/* cache all entries for 60 seconds for to save ldap-queries (cache is updated

 * after this period if admins do not use pdbedit or usermanager but manipulate

 * ldap directly) - gd */

#define DATABASE_VERSION  3

#define AP_TTL      60

struct ap_table {

  enum pdb_policy_type type;

  const char *string;

  uint32_t default_val;

  const char *description;

  const char *ldap_attr;

};

static const struct ap_table account_policy_names[] = {

  {PDB_POLICY_MIN_PASSWORD_LEN, "min password length", MINPASSWDLENGTH,

    "Minimal password length (default: 5)",

    "sambaMinPwdLength" },

  {PDB_POLICY_PASSWORD_HISTORY, "password history", 0,

    "Length of Password History Entries (default: 0 => off)",

    "sambaPwdHistoryLength" },

  {PDB_POLICY_USER_MUST_LOGON_TO_CHG_PASS, "user must logon to change password", 0,

    "Force Users to logon for password change (default: 0 => off, 2 => on)",

    "sambaLogonToChgPwd" },

  {PDB_POLICY_MAX_PASSWORD_AGE, "maximum password age", (uint32_t) -1,

    "Maximum password age, in seconds (default: -1 => never expire passwords)",

    "sambaMaxPwdAge" },

  {PDB_POLICY_MIN_PASSWORD_AGE,"minimum password age", 0,

    "Minimal password age, in seconds (default: 0 => allow immediate password change)",

    "sambaMinPwdAge" },

  {PDB_POLICY_LOCK_ACCOUNT_DURATION, "lockout duration", 30,

    "Lockout duration in minutes (default: 30, -1 => forever)",

    "sambaLockoutDuration" },

  {PDB_POLICY_RESET_COUNT_TIME, "reset count minutes", 30,

    "Reset time after lockout in minutes (default: 30)",

    "sambaLockoutObservationWindow" },

  {PDB_POLICY_BAD_ATTEMPT_LOCKOUT, "bad lockout attempt", 0,

    "Lockout users after bad logon attempts (default: 0 => off)",

    "sambaLockoutThreshold" },

  {PDB_POLICY_TIME_TO_LOGOUT, "disconnect time", (uint32_t) -1,

    "Disconnect Users outside logon hours (default: -1 => off, 0 => on)",

    "sambaForceLogoff" },

  {PDB_POLICY_REFUSE_MACHINE_PW_CHANGE, "refuse machine password change", 0,

    "Allow Machine Password changes (default: 0 => off)",

    "sambaRefuseMachinePwdChange" },

  {0, NULL, 0, "", NULL}

};

void account_policy_names_list(TALLOC_CTX *mem_ctx, const char ***names, int *num_names)

{

  const char **nl;

  int i, count = ARRAY_SIZE(account_policy_names);

  nl = talloc_array(mem_ctx, const char *, count);

  if (!nl) {

    *num_names = 0;

    return;

  }

  for (i=0; i<count; i++) {

    nl[i] = account_policy_names[i].string;

  }

  /* Do not return the last null entry */

  *num_names = count-1;

  *names = nl;

  return;

}

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

Get the account policy name as a string from its #define'ed number

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

const char *decode_account_policy_name(enum pdb_policy_type type)

{

  int i;

  for (i=0; account_policy_names[i].string; i++) {

    if (type == account_policy_names[i].type) {

      return account_policy_names[i].string;

    }

  }

  return NULL;

}

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

Get the account policy LDAP attribute as a string from its #define'ed number

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

const char *get_account_policy_attr(enum pdb_policy_type type)

{

  int i;

  for (i=0; account_policy_names[i].type; i++) {

    if (type == account_policy_names[i].type) {

      return account_policy_names[i].ldap_attr;

    }

  }

  return NULL;

}

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

Get the account policy description as a string from its #define'ed number

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

const char *account_policy_get_desc(enum pdb_policy_type type)

{

  int i;

  for (i=0; account_policy_names[i].string; i++) {

    if (type == account_policy_names[i].type) {

      return account_policy_names[i].description;

    }

  }

  return NULL;

}

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

Get the account policy name as a string from its #define'ed number

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

enum pdb_policy_type account_policy_name_to_typenum(const char *name)

{

  int i;

  for (i=0; account_policy_names[i].string; i++) {

    if (strcmp(name, account_policy_names[i].string) == 0) {

      return account_policy_names[i].type;

    }

  }

  return 0;

}

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

Get default value for account policy

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

bool account_policy_get_default(enum pdb_policy_type type, uint32_t *val)

{

  int i;

  for (i=0; account_policy_names[i].type; i++) {

    if (account_policy_names[i].type == type) {

      *val = account_policy_names[i].default_val;

      return True;

    }

  }

  DEBUG(0,("no default for account_policy index %d found. This should never happen\n",

    type));

  return False;

}

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

 Set default for a type if it is empty

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

static bool account_policy_set_default_on_empty(enum pdb_policy_type type)

{

  uint32_t value;

  if (!account_policy_get(type, &value) &&

      !account_policy_get_default(type, &value)) {

    return False;

  }

  return account_policy_set(type, value);

}

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

 Open the account policy tdb.

***`*************************************************************************/

bool init_account_policy(void)

{

  const char *vstring = "INFO/version";

  uint32_t version = 0;

  int i;

  NTSTATUS status;

  char *db_path;

  if (db != NULL) {

    return True;

  }

  db_path = state_path(talloc_tos(), "account_policy.tdb");

  if (db_path == NULL) {

    return false;

  }

  db = db_open(NULL, db_path, 0, TDB_DEFAULT,

         O_RDWR, 0600, DBWRAP_LOCK_ORDER_1, DBWRAP_FLAG_NONE);

  if (db == NULL) { /* the account policies files does not exist or open

         * failed, try to create a new one */

    db = db_open(NULL, db_path, 0,

           TDB_DEFAULT, O_RDWR|O_CREAT, 0600,

           DBWRAP_LOCK_ORDER_1, DBWRAP_FLAG_NONE);

    if (db == NULL) {

      DEBUG(0,("Failed to open account policy database\n"));

      TALLOC_FREE(db_path);

      return False;

    }

  }

  TALLOC_FREE(db_path);

  status = dbwrap_fetch_uint32_bystring(db, vstring, &version);

  if (!NT_STATUS_IS_OK(status)) {

    version = 0;

  }

  if (version == DATABASE_VERSION) {

    return true;

  }

  /* handle a Samba upgrade */

  if (dbwrap_transaction_start(db) != 0) {

    DEBUG(0, ("transaction_start failed\n"));

    TALLOC_FREE(db);

    return false;

  }

  status = dbwrap_fetch_uint32_bystring(db, vstring, &version);

  if (!NT_STATUS_IS_OK(status)) {

    version = 0;

  }

  if (version == DATABASE_VERSION) {

    /*

     * Race condition

     */

    if (dbwrap_transaction_cancel(db)) {

      smb_panic("transaction_cancel failed");

    }

    return true;

  }

  if (version != DATABASE_VERSION) {

    status = dbwrap_store_uint32_bystring(db, vstring,

                  DATABASE_VERSION);

    if (!NT_STATUS_IS_OK(status)) {

      DEBUG(0, ("dbwrap_store_uint32_t failed: %s\n",

          nt_errstr(status)));

      goto cancel;

    }

    for (i=0; account_policy_names[i].type; i++) {

      if (!account_policy_set_default_on_empty(account_policy_names[i].type)) {

        DEBUG(0,("failed to set default value in account policy tdb\n"));

        goto cancel;

      }

    }

  }

  /* These exist by default on NT4 in [HKLM\SECURITY\Policy\Accounts] */

  privilege_create_account( &global_sid_World );

  privilege_create_account( &global_sid_Builtin_Account_Operators );

  privilege_create_account( &global_sid_Builtin_Server_Operators );

  privilege_create_account( &global_sid_Builtin_Print_Operators );

  privilege_create_account( &global_sid_Builtin_Backup_Operators );

  /* BUILTIN\Administrators get everything -- *always* */

  if ( lp_enable_privileges() ) {

    if ( !grant_all_privileges( &global_sid_Builtin_Administrators ) ) {

      DEBUG(1,("init_account_policy: Failed to grant privileges "

        "to BUILTIN\\Administrators!\n"));

    }

  }

  if (dbwrap_transaction_commit(db) != 0) {

    DEBUG(0, ("transaction_commit failed\n"));

    TALLOC_FREE(db);

    return false;

  }

  return True;

 cancel:

  if (dbwrap_transaction_cancel(db)) {

    smb_panic("transaction_cancel failed");

  }

  TALLOC_FREE(db);

  return false;

}

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

Get an account policy (from tdb)

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

bool account_policy_get(enum pdb_policy_type type, uint32_t *value)

{

  const char *name;

  uint32_t regval;

  NTSTATUS status;

  if (!init_account_policy()) {

    return False;

  }

  if (value) {

    *value = 0;

  }

  name = decode_account_policy_name(type);

  if (name == NULL) {

    DEBUG(1, ("account_policy_get: Field %d is not a valid account policy type!  Cannot get, returning 0.\n", type));

    return False;

  }

  status = dbwrap_fetch_uint32_bystring(db, name, &regval);

  if (!NT_STATUS_IS_OK(status)) {

    DEBUG(2, ("account_policy_get: tdb_fetch_uint32_t failed for type %d (%s), returning 0\n", type, name));

    return False;

  }

  if (value) {

    *value = regval;

  }

  DEBUG(10,("account_policy_get: name: %s, val: %d\n", name, regval));

  return True;

}

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

Set an account policy (in tdb)

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

bool account_policy_set(enum pdb_policy_type type, uint32_t value)

{

  const char *name;

  NTSTATUS status;

  if (!init_account_policy()) {

    return False;

  }

  name = decode_account_policy_name(type);

  if (name == NULL) {

    DEBUG(1, ("Field %d is not a valid account policy type!  Cannot set.\n", type));

    return False;

  }

  status = dbwrap_trans_store_uint32_bystring(db, name, value);

  if (!NT_STATUS_IS_OK(status)) {

    DEBUG(1, ("store_uint32_t failed for type %d (%s) on value "

        "%u: %s\n", type, name, value, nt_errstr(status)));

    return False;

  }

  DEBUG(10,("account_policy_set: name: %s, value: %d\n", name, value));

  return True;

}

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

Set an account policy in the cache

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

bool cache_account_policy_set(enum pdb_policy_type type, uint32_t value)

{

  const char *policy_name = NULL;

  char *cache_key = NULL;

  char *cache_value = NULL;

  bool ret = False;

  policy_name = decode_account_policy_name(type);

  if (policy_name == NULL) {

    DEBUG(0,("cache_account_policy_set: no policy found\n"));

    return False;

  }

  if (asprintf(&cache_key, "ACCT_POL/%s", policy_name) < 0) {

    DEBUG(0, ("asprintf failed\n"));

    goto done;

  }

  if (asprintf(&cache_value, "%lu\n", (unsigned long)value) < 0) {

    DEBUG(0, ("asprintf failed\n"));

    goto done;

  }

  DEBUG(10,("cache_account_policy_set: updating account pol cache\n"));

  ret = gencache_set(cache_key, cache_value, time(NULL)+AP_TTL);

 done:

  SAFE_FREE(cache_key);

  SAFE_FREE(cache_value);

  return ret;

}

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

Get an account policy from the cache

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

bool cache_account_policy_get(enum pdb_policy_type type, uint32_t *value)

{

  const char *policy_name = NULL;

  char *cache_key = NULL;

  char *cache_value = NULL;

  bool ret = False;

  policy_name = decode_account_policy_name(type);

  if (policy_name == NULL) {

    DEBUG(0,("cache_account_policy_set: no policy found\n"));

    return False;

  }

  if (asprintf(&cache_key, "ACCT_POL/%s", policy_name) < 0) {

    DEBUG(0, ("asprintf failed\n"));

    goto done;

  }

  if (gencache_get(cache_key, talloc_tos(), &cache_value, NULL)) {

    int error = 0;

    uint32_t tmp;

    tmp = smb_strtoul(cache_value,

          NULL,

          10,

          &error,

          SMB_STR_STANDARD);

    if (error != 0) {

      goto done;

    }

    *value = tmp;

    ret = True;

  }

 done:

  SAFE_FREE(cache_key);

  TALLOC_FREE(cache_value);

  return ret;

}

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

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

struct db_context *get_account_pol_db( void )

{

  if ( db == NULL ) {

    if ( !init_account_policy() ) {

      return NULL;

    }

  }

  return db;

}