MediaWiki/includes/Block.php

<?php
/**
 * Blocks and bans object
 *
 * 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 2 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, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 */

use Wikimedia\Rdbms\Database;
use Wikimedia\Rdbms\IDatabase;
use MediaWiki\MediaWikiServices;

class Block {
	/** @var string */
	public $mReason;

	/** @var string */
	public $mTimestamp;

	/** @var bool */
	public $mAuto;

	/** @var string */
	public $mExpiry;

	/** @var bool */
	public $mHideName;

	/** @var int */
	public $mParentBlockId;

	/** @var int */
	private $mId;

	/** @var bool */
	private $mFromMaster;

	/** @var bool */
	private $mBlockEmail;

	/** @var bool */
	private $mDisableUsertalk;

	/** @var bool */
	private $mCreateAccount;

	/** @var User|string */
	private $target;

	/** @var int Hack for foreign blocking (CentralAuth) */
	private $forcedTargetID;

	/** @var int Block::TYPE_ constant. Can only be USER, IP or RANGE internally */
	private $type;

	/** @var User */
	private $blocker;

	/** @var bool */
	private $isHardblock;

	/** @var bool */
	private $isAutoblocking;

	/** @var string|null */
	private $systemBlockType;

	# TYPE constants
	const TYPE_USER = 1;
	const TYPE_IP = 2;
	const TYPE_RANGE = 3;
	const TYPE_AUTO = 4;
	const TYPE_ID = 5;

	/**
	 * Create a new block with specified parameters on a user, IP or IP range.
	 *
	 * @param array $options Parameters of the block:
	 *     address string|User  Target user name, User object, IP address or IP range
	 *     user int             Override target user ID (for foreign users)
	 *     by int               User ID of the blocker
	 *     reason string        Reason of the block
	 *     timestamp string     The time at which the block comes into effect
	 *     auto bool            Is this an automatic block?
	 *     expiry string        Timestamp of expiration of the block or 'infinity'
	 *     anonOnly bool        Only disallow anonymous actions
	 *     createAccount bool   Disallow creation of new accounts
	 *     enableAutoblock bool Enable automatic blocking
	 *     hideName bool        Hide the target user name
	 *     blockEmail bool      Disallow sending emails
	 *     allowUsertalk bool   Allow the target to edit its own talk page
	 *     byText string        Username of the blocker (for foreign users)
	 *     systemBlock string   Indicate that this block is automatically
	 *                          created by MediaWiki rather than being stored
	 *                          in the database. Value is a string to return
	 *                          from self::getSystemBlockType().
	 *
	 * @since 1.26 accepts $options array instead of individual parameters; order
	 * of parameters above reflects the original order
	 */
	function __construct( $options = [] ) {
		$defaults = [
			'address'         => '',
			'user'            => null,
			'by'              => null,
			'reason'          => '',
			'timestamp'       => '',
			'auto'            => false,
			'expiry'          => '',
			'anonOnly'        => false,
			'createAccount'   => false,
			'enableAutoblock' => false,
			'hideName'        => false,
			'blockEmail'      => false,
			'allowUsertalk'   => false,
			'byText'          => '',
			'systemBlock'     => null,
		];

		if ( func_num_args() > 1 || !is_array( $options ) ) {
			$options = array_combine(
				array_slice( array_keys( $defaults ), 0, func_num_args() ),
				func_get_args()
			);
			wfDeprecated( __METHOD__ . ' with multiple arguments', '1.26' );
		}

		$options += $defaults;

		$this->setTarget( $options['address'] );

		if ( $this->target instanceof User && $options['user'] ) {
			# Needed for foreign users
			$this->forcedTargetID = $options['user'];
		}

		if ( $options['by'] ) {
			# Local user
			$this->setBlocker( User::newFromId( $options['by'] ) );
		} else {
			# Foreign user
			$this->setBlocker( $options['byText'] );
		}

		$this->mReason = $options['reason'];
		$this->mTimestamp = wfTimestamp( TS_MW, $options['timestamp'] );
		$this->mExpiry = wfGetDB( DB_REPLICA )->decodeExpiry( $options['expiry'] );

		# Boolean settings
		$this->mAuto = (bool)$options['auto'];
		$this->mHideName = (bool)$options['hideName'];
		$this->isHardblock( !$options['anonOnly'] );
		$this->isAutoblocking( (bool)$options['enableAutoblock'] );

		# Prevention measures
		$this->prevents( 'sendemail', (bool)$options['blockEmail'] );
		$this->prevents( 'editownusertalk', !$options['allowUsertalk'] );
		$this->prevents( 'createaccount', (bool)$options['createAccount'] );

		$this->mFromMaster = false;
		$this->systemBlockType = $options['systemBlock'];
	}

	/**
	 * Load a blocked user from their block id.
	 *
	 * @param int $id Block id to search for
	 * @return Block|null
	 */
	public static function newFromID( $id ) {
		$dbr = wfGetDB( DB_REPLICA );
		$res = $dbr->selectRow(
			'ipblocks',
			self::selectFields(),
			[ 'ipb_id' => $id ],
			__METHOD__
		);
		if ( $res ) {
			return self::newFromRow( $res );
		} else {
			return null;
		}
	}

	/**
	 * Return the list of ipblocks fields that should be selected to create
	 * a new block.
	 * @todo Deprecate this in favor of a method that returns tables and joins
	 *  as well, and use CommentStore::getJoin().
	 * @return array
	 */
	public static function selectFields() {
		return [
			'ipb_id',
			'ipb_address',
			'ipb_by',
			'ipb_by_text',
			'ipb_timestamp',
			'ipb_auto',
			'ipb_anon_only',
			'ipb_create_account',
			'ipb_enable_autoblock',
			'ipb_expiry',
			'ipb_deleted',
			'ipb_block_email',
			'ipb_allow_usertalk',
			'ipb_parent_block_id',
		] + CommentStore::newKey( 'ipb_reason' )->getFields();
	}

	/**
	 * Check if two blocks are effectively equal.  Doesn't check irrelevant things like
	 * the blocking user or the block timestamp, only things which affect the blocked user
	 *
	 * @param Block $block
	 *
	 * @return bool
	 */
	public function equals( Block $block ) {
		return (
			(string)$this->target == (string)$block->target
			&& $this->type == $block->type
			&& $this->mAuto == $block->mAuto
			&& $this->isHardblock() == $block->isHardblock()
			&& $this->prevents( 'createaccount' ) == $block->prevents( 'createaccount' )
			&& $this->mExpiry == $block->mExpiry
			&& $this->isAutoblocking() == $block->isAutoblocking()
			&& $this->mHideName == $block->mHideName
			&& $this->prevents( 'sendemail' ) == $block->prevents( 'sendemail' )
			&& $this->prevents( 'editownusertalk' ) == $block->prevents( 'editownusertalk' )
			&& $this->mReason == $block->mReason
		);
	}

	/**
	 * Load a block from the database which affects the already-set $this->target:
	 *     1) A block directly on the given user or IP
	 *     2) A rangeblock encompassing the given IP (smallest first)
	 *     3) An autoblock on the given IP
	 * @param User|string $vagueTarget Also search for blocks affecting this target.  Doesn't
	 *     make any sense to use TYPE_AUTO / TYPE_ID here. Leave blank to skip IP lookups.
	 * @throws MWException
	 * @return bool Whether a relevant block was found
	 */
	protected function newLoad( $vagueTarget = null ) {
		$db = wfGetDB( $this->mFromMaster ? DB_MASTER : DB_REPLICA );

		if ( $this->type !== null ) {
			$conds = [
				'ipb_address' => [ (string)$this->target ],
			];
		} else {
			$conds = [ 'ipb_address' => [] ];
		}

		# Be aware that the != '' check is explicit, since empty values will be
		# passed by some callers (T31116)
		if ( $vagueTarget != '' ) {
			list( $target, $type ) = self::parseTarget( $vagueTarget );
			switch ( $type ) {
				case self::TYPE_USER:
					# Slightly weird, but who are we to argue?
					$conds['ipb_address'][] = (string)$target;
					break;

				case self::TYPE_IP:
					$conds['ipb_address'][] = (string)$target;
					$conds[] = self::getRangeCond( IP::toHex( $target ) );
					$conds = $db->makeList( $conds, LIST_OR );
					break;

				case self::TYPE_RANGE:
					list( $start, $end ) = IP::parseRange( $target );
					$conds['ipb_address'][] = (string)$target;
					$conds[] = self::getRangeCond( $start, $end );
					$conds = $db->makeList( $conds, LIST_OR );
					break;

				default:
					throw new MWException( "Tried to load block with invalid type" );
			}
		}

		$res = $db->select( 'ipblocks', self::selectFields(), $conds, __METHOD__ );

		# This result could contain a block on the user, a block on the IP, and a russian-doll
		# set of rangeblocks.  We want to choose the most specific one, so keep a leader board.
		$bestRow = null;

		# Lower will be better
		$bestBlockScore = 100;

		# This is begging for $this = $bestBlock, but that's not allowed in PHP :(
		$bestBlockPreventsEdit = null;

		foreach ( $res as $row ) {
			$block = self::newFromRow( $row );

			# Don't use expired blocks
			if ( $block->isExpired() ) {
				continue;
			}

			# Don't use anon only blocks on users
			if ( $this->type == self::TYPE_USER && !$block->isHardblock() ) {
				continue;
			}

			if ( $block->getType() == self::TYPE_RANGE ) {
				# This is the number of bits that are allowed to vary in the block, give
				# or take some floating point errors
				$end = Wikimedia\base_convert( $block->getRangeEnd(), 16, 10 );
				$start = Wikimedia\base_convert( $block->getRangeStart(), 16, 10 );
				$size = log( $end - $start + 1, 2 );

				# This has the nice property that a /32 block is ranked equally with a
				# single-IP block, which is exactly what it is...
				$score = self::TYPE_RANGE - 1 + ( $size / 128 );

			} else {
				$score = $block->getType();
			}

			if ( $score < $bestBlockScore ) {
				$bestBlockScore = $score;
				$bestRow = $row;
				$bestBlockPreventsEdit = $block->prevents( 'edit' );
			}
		}

		if ( $bestRow !== null ) {
			$this->initFromRow( $bestRow );
			$this->prevents( 'edit', $bestBlockPreventsEdit );
			return true;
		} else {
			return false;
		}
	}

	/**
	 * Get a set of SQL conditions which will select rangeblocks encompassing a given range
	 * @param string $start Hexadecimal IP representation
	 * @param string $end Hexadecimal IP representation, or null to use $start = $end
	 * @return string
	 */
	public static function getRangeCond( $start, $end = null ) {
		if ( $end === null ) {
			$end = $start;
		}
		# Per T16634, we want to include relevant active rangeblocks; for
		# rangeblocks, we want to include larger ranges which enclose the given
		# range. We know that all blocks must be smaller than $wgBlockCIDRLimit,
		# so we can improve performance by filtering on a LIKE clause
		$chunk = self::getIpFragment( $start );
		$dbr = wfGetDB( DB_REPLICA );
		$like = $dbr->buildLike( $chunk, $dbr->anyString() );

		# Fairly hard to make a malicious SQL statement out of hex characters,
		# but stranger things have happened...
		$safeStart = $dbr->addQuotes( $start );
		$safeEnd = $dbr->addQuotes( $end );

		return $dbr->makeList(
			[
				"ipb_range_start $like",
				"ipb_range_start <= $safeStart",
				"ipb_range_end >= $safeEnd",
			],
			LIST_AND
		);
	}

	/**
	 * Get the component of an IP address which is certain to be the same between an IP
	 * address and a rangeblock containing that IP address.
	 * @param string $hex Hexadecimal IP representation
	 * @return string
	 */
	protected static function getIpFragment( $hex ) {
		global $wgBlockCIDRLimit;
		if ( substr( $hex, 0, 3 ) == 'v6-' ) {
			return 'v6-' . substr( substr( $hex, 3 ), 0, floor( $wgBlockCIDRLimit['IPv6'] / 4 ) );
		} else {
			return substr( $hex, 0, floor( $wgBlockCIDRLimit['IPv4'] / 4 ) );
		}
	}

	/**
	 * Given a database row from the ipblocks table, initialize
	 * member variables
	 * @param stdClass $row A row from the ipblocks table
	 */
	protected function initFromRow( $row ) {
		$this->setTarget( $row->ipb_address );
		if ( $row->ipb_by ) { // local user
			$this->setBlocker( User::newFromId( $row->ipb_by ) );
		} else { // foreign user
			$this->setBlocker( $row->ipb_by_text );
		}

		$this->mTimestamp = wfTimestamp( TS_MW, $row->ipb_timestamp );
		$this->mAuto = $row->ipb_auto;
		$this->mHideName = $row->ipb_deleted;
		$this->mId = (int)$row->ipb_id;
		$this->mParentBlockId = $row->ipb_parent_block_id;

		// I wish I didn't have to do this
		$db = wfGetDB( DB_REPLICA );
		$this->mExpiry = $db->decodeExpiry( $row->ipb_expiry );
		$this->mReason = CommentStore::newKey( 'ipb_reason' )
			// Legacy because $row probably came from self::selectFields()
			->getCommentLegacy( $db, $row )->text;

		$this->isHardblock( !$row->ipb_anon_only );
		$this->isAutoblocking( $row->ipb_enable_autoblock );

		$this->prevents( 'createaccount', $row->ipb_create_account );
		$this->prevents( 'sendemail', $row->ipb_block_email );
		$this->prevents( 'editownusertalk', !$row->ipb_allow_usertalk );
	}

	/**
	 * Create a new Block object from a database row
	 * @param stdClass $row Row from the ipblocks table
	 * @return Block
	 */
	public static function newFromRow( $row ) {
		$block = new Block;
		$block->initFromRow( $row );
		return $block;
	}

	/**
	 * Delete the row from the IP blocks table.
	 *
	 * @throws MWException
	 * @return bool
	 */
	public function delete() {
		if ( wfReadOnly() ) {
			return false;
		}

		if ( !$this->getId() ) {
			throw new MWException( "Block::delete() requires that the mId member be filled\n" );
		}

		$dbw = wfGetDB( DB_MASTER );
		$dbw->delete( 'ipblocks', [ 'ipb_parent_block_id' => $this->getId() ], __METHOD__ );
		$dbw->delete( 'ipblocks', [ 'ipb_id' => $this->getId() ], __METHOD__ );

		return $dbw->affectedRows() > 0;
	}

	/**
	 * Insert a block into the block table. Will fail if there is a conflicting
	 * block (same name and options) already in the database.
	 *
	 * @param IDatabase $dbw If you have one available
	 * @return bool|array False on failure, assoc array on success:
	 *	('id' => block ID, 'autoIds' => array of autoblock IDs)
	 */
	public function insert( $dbw = null ) {
		global $wgBlockDisablesLogin;

		if ( $this->getSystemBlockType() !== null ) {
			throw new MWException( 'Cannot insert a system block into the database' );
		}

		wfDebug( "Block::insert; timestamp {$this->mTimestamp}\n" );

		if ( $dbw === null ) {
			$dbw = wfGetDB( DB_MASTER );
		}

		# Periodic purge via commit hooks
		if ( mt_rand( 0, 9 ) == 0 ) {
			self::purgeExpired();
		}

		$row = $this->getDatabaseArray( $dbw );

		$dbw->insert( 'ipblocks', $row, __METHOD__, [ 'IGNORE' ] );
		$affected = $dbw->affectedRows();
		$this->mId = $dbw->insertId();

		# Don't collide with expired blocks.
		# Do this after trying to insert to avoid locking.
		if ( !$affected ) {
			# T96428: The ipb_address index uses a prefix on a field, so
			# use a standard SELECT + DELETE to avoid annoying gap locks.
			$ids = $dbw->selectFieldValues( 'ipblocks',
				'ipb_id',
				[
					'ipb_address' => $row['ipb_address'],
					'ipb_user' => $row['ipb_user'],
					'ipb_expiry < ' . $dbw->addQuotes( $dbw->timestamp() )
				],
				__METHOD__
			);
			if ( $ids ) {
				$dbw->delete( 'ipblocks', [ 'ipb_id' => $ids ], __METHOD__ );
				$dbw->insert( 'ipblocks', $row, __METHOD__, [ 'IGNORE' ] );
				$affected = $dbw->affectedRows();
				$this->mId = $dbw->insertId();
			}
		}

		if ( $affected ) {
			$auto_ipd_ids = $this->doRetroactiveAutoblock();

			if ( $wgBlockDisablesLogin && $this->target instanceof User ) {
				// Change user login token to force them to be logged out.
				$this->target->setToken();
				$this->target->saveSettings();
			}

			return [ 'id' => $this->mId, 'autoIds' => $auto_ipd_ids ];
		}

		return false;
	}

	/**
	 * Update a block in the DB with new parameters.
	 * The ID field needs to be loaded first.
	 *
	 * @return bool|array False on failure, array on success:
	 *   ('id' => block ID, 'autoIds' => array of autoblock IDs)
	 */
	public function update() {
		wfDebug( "Block::update; timestamp {$this->mTimestamp}\n" );
		$dbw = wfGetDB( DB_MASTER );

		$dbw->startAtomic( __METHOD__ );

		$dbw->update(
			'ipblocks',
			$this->getDatabaseArray( $dbw ),
			[ 'ipb_id' => $this->getId() ],
			__METHOD__
		);

		$affected = $dbw->affectedRows();

		if ( $this->isAutoblocking() ) {
			// update corresponding autoblock(s) (T50813)
			$dbw->update(
				'ipblocks',
				$this->getAutoblockUpdateArray( $dbw ),
				[ 'ipb_parent_block_id' => $this->getId() ],
				__METHOD__
			);
		} else {
			// autoblock no longer required, delete corresponding autoblock(s)
			$dbw->delete(
				'ipblocks',
				[ 'ipb_parent_block_id' => $this->getId() ],
				__METHOD__
			);
		}

		$dbw->endAtomic( __METHOD__ );

		if ( $affected ) {
			$auto_ipd_ids = $this->doRetroactiveAutoblock();
			return [ 'id' => $this->mId, 'autoIds' => $auto_ipd_ids ];
		}

		return false;
	}

	/**
	 * Get an array suitable for passing to $dbw->insert() or $dbw->update()
	 * @param IDatabase $dbw
	 * @return array
	 */
	protected function getDatabaseArray( IDatabase $dbw ) {
		$expiry = $dbw->encodeExpiry( $this->mExpiry );

		if ( $this->forcedTargetID ) {
			$uid = $this->forcedTargetID;
		} else {
			$uid = $this->target instanceof User ? $this->target->getId() : 0;
		}

		$a = [
			'ipb_address'          => (string)$this->target,
			'ipb_user'             => $uid,
			'ipb_by'               => $this->getBy(),
			'ipb_by_text'          => $this->getByName(),
			'ipb_timestamp'        => $dbw->timestamp( $this->mTimestamp ),
			'ipb_auto'             => $this->mAuto,
			'ipb_anon_only'        => !$this->isHardblock(),
			'ipb_create_account'   => $this->prevents( 'createaccount' ),
			'ipb_enable_autoblock' => $this->isAutoblocking(),
			'ipb_expiry'           => $expiry,
			'ipb_range_start'      => $this->getRangeStart(),
			'ipb_range_end'        => $this->getRangeEnd(),
			'ipb_deleted'          => intval( $this->mHideName ), // typecast required for SQLite
			'ipb_block_email'      => $this->prevents( 'sendemail' ),
			'ipb_allow_usertalk'   => !$this->prevents( 'editownusertalk' ),
			'ipb_parent_block_id'  => $this->mParentBlockId
		] + CommentStore::newKey( 'ipb_reason' )->insert( $dbw, $this->mReason );

		return $a;
	}

	/**
	 * @param IDatabase $dbw
	 * @return array
	 */
	protected function getAutoblockUpdateArray( IDatabase $dbw ) {
		return [
			'ipb_by'               => $this->getBy(),
			'ipb_by_text'          => $this->getByName(),
			'ipb_create_account'   => $this->prevents( 'createaccount' ),
			'ipb_deleted'          => (int)$this->mHideName, // typecast required for SQLite
			'ipb_allow_usertalk'   => !$this->prevents( 'editownusertalk' ),
		] + CommentStore::newKey( 'ipb_reason' )->insert( $dbw, $this->mReason );
	}

	/**
	 * Retroactively autoblocks the last IP used by the user (if it is a user)
	 * blocked by this Block.
	 *
	 * @return array Block IDs of retroactive autoblocks made
	 */
	protected function doRetroactiveAutoblock() {
		$blockIds = [];
		# If autoblock is enabled, autoblock the LAST IP(s) used
		if ( $this->isAutoblocking() && $this->getType() == self::TYPE_USER ) {
			wfDebug( "Doing retroactive autoblocks for " . $this->getTarget() . "\n" );

			$continue = Hooks::run(
				'PerformRetroactiveAutoblock', [ $this, &$blockIds ] );

			if ( $continue ) {
				self::defaultRetroactiveAutoblock( $this, $blockIds );
			}
		}
		return $blockIds;
	}

	/**
	 * Retroactively autoblocks the last IP used by the user (if it is a user)
	 * blocked by this Block. This will use the recentchanges table.
	 *
	 * @param Block $block
	 * @param array &$blockIds
	 */
	protected static function defaultRetroactiveAutoblock( Block $block, array &$blockIds ) {
		global $wgPutIPinRC;

		// No IPs are in recentchanges table, so nothing to select
		if ( !$wgPutIPinRC ) {
			return;
		}

		$dbr = wfGetDB( DB_REPLICA );

		$options = [ 'ORDER BY' => 'rc_timestamp DESC' ];
		$conds = [ 'rc_user_text' => (string)$block->getTarget() ];

		// Just the last IP used.
		$options['LIMIT'] = 1;

		$res = $dbr->select( 'recentchanges', [ 'rc_ip' ], $conds,
			__METHOD__, $options );

		if ( !$res->numRows() ) {
			# No results, don't autoblock anything
			wfDebug( "No IP found to retroactively autoblock\n" );
		} else {
			foreach ( $res as $row ) {
				if ( $row->rc_ip ) {
					$id = $block->doAutoblock( $row->rc_ip );
					if ( $id ) {
						$blockIds[] = $id;
					}
				}
			}
		}
	}

	/**
	 * Checks whether a given IP is on the autoblock whitelist.
	 * TODO: this probably belongs somewhere else, but not sure where...
	 *
	 * @param string $ip The IP to check
	 * @return bool
	 */
	public static function isWhitelistedFromAutoblocks( $ip ) {
		// Try to get the autoblock_whitelist from the cache, as it's faster
		// than getting the msg raw and explode()'ing it.
		$cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
		$lines = $cache->getWithSetCallback(
			$cache->makeKey( 'ipb', 'autoblock', 'whitelist' ),
			$cache::TTL_DAY,
			function ( $curValue, &$ttl, array &$setOpts ) {
				$setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );

				return explode( "\n",
					wfMessage( 'autoblock_whitelist' )->inContentLanguage()->plain() );
			}
		);

		wfDebug( "Checking the autoblock whitelist..\n" );

		foreach ( $lines as $line ) {
			# List items only
			if ( substr( $line, 0, 1 ) !== '*' ) {
				continue;
			}

			$wlEntry = substr( $line, 1 );
			$wlEntry = trim( $wlEntry );

			wfDebug( "Checking $ip against $wlEntry..." );

			# Is the IP in this range?
			if ( IP::isInRange( $ip, $wlEntry ) ) {
				wfDebug( " IP $ip matches $wlEntry, not autoblocking\n" );
				return true;
			} else {
				wfDebug( " No match\n" );
			}
		}

		return false;
	}

	/**
	 * Autoblocks the given IP, referring to this Block.
	 *
	 * @param string $autoblockIP The IP to autoblock.
	 * @return int|bool Block ID if an autoblock was inserted, false if not.
	 */
	public function doAutoblock( $autoblockIP ) {
		# If autoblocks are disabled, go away.
		if ( !$this->isAutoblocking() ) {
			return false;
		}

		# Don't autoblock for system blocks
		if ( $this->getSystemBlockType() !== null ) {
			throw new MWException( 'Cannot autoblock from a system block' );
		}

		# Check for presence on the autoblock whitelist.
		if ( self::isWhitelistedFromAutoblocks( $autoblockIP ) ) {
			return false;
		}

		// Avoid PHP 7.1 warning of passing $this by reference
		$block = $this;
		# Allow hooks to cancel the autoblock.
		if ( !Hooks::run( 'AbortAutoblock', [ $autoblockIP, &$block ] ) ) {
			wfDebug( "Autoblock aborted by hook.\n" );
			return false;
		}

		# It's okay to autoblock. Go ahead and insert/update the block...

		# Do not add a *new* block if the IP is already blocked.
		$ipblock = self::newFromTarget( $autoblockIP );
		if ( $ipblock ) {
			# Check if the block is an autoblock and would exceed the user block
			# if renewed. If so, do nothing, otherwise prolong the block time...
			if ( $ipblock->mAuto && // @todo Why not compare $ipblock->mExpiry?
				$this->mExpiry > self::getAutoblockExpiry( $ipblock->mTimestamp )
			) {
				# Reset block timestamp to now and its expiry to
				# $wgAutoblockExpiry in the future
				$ipblock->updateTimestamp();
			}
			return false;
		}

		# Make a new block object with the desired properties.
		$autoblock = new Block;
		wfDebug( "Autoblocking {$this->getTarget()}@" . $autoblockIP . "\n" );
		$autoblock->setTarget( $autoblockIP );
		$autoblock->setBlocker( $this->getBlocker() );
		$autoblock->mReason = wfMessage( 'autoblocker', $this->getTarget(), $this->mReason )
			->inContentLanguage()->plain();
		$timestamp = wfTimestampNow();
		$autoblock->mTimestamp = $timestamp;
		$autoblock->mAuto = 1;
		$autoblock->prevents( 'createaccount', $this->prevents( 'createaccount' ) );
		# Continue suppressing the name if needed
		$autoblock->mHideName = $this->mHideName;
		$autoblock->prevents( 'editownusertalk', $this->prevents( 'editownusertalk' ) );
		$autoblock->mParentBlockId = $this->mId;

		if ( $this->mExpiry == 'infinity' ) {
			# Original block was indefinite, start an autoblock now
			$autoblock->mExpiry = self::getAutoblockExpiry( $timestamp );
		} else {
			# If the user is already blocked with an expiry date, we don't
			# want to pile on top of that.
			$autoblock->mExpiry = min( $this->mExpiry, self::getAutoblockExpiry( $timestamp ) );
		}

		# Insert the block...
		$status = $autoblock->insert();
		return $status
			? $status['id']
			: false;
	}

	/**
	 * Check if a block has expired. Delete it if it is.
	 * @return bool
	 */
	public function deleteIfExpired() {
		if ( $this->isExpired() ) {
			wfDebug( "Block::deleteIfExpired() -- deleting\n" );
			$this->delete();
			$retVal = true;
		} else {
			wfDebug( "Block::deleteIfExpired() -- not expired\n" );
			$retVal = false;
		}

		return $retVal;
	}

	/**
	 * Has the block expired?
	 * @return bool
	 */
	public function isExpired() {
		$timestamp = wfTimestampNow();
		wfDebug( "Block::isExpired() checking current " . $timestamp . " vs $this->mExpiry\n" );

		if ( !$this->mExpiry ) {
			return false;
		} else {
			return $timestamp > $this->mExpiry;
		}
	}

	/**
	 * Is the block address valid (i.e. not a null string?)
	 * @return bool
	 */
	public function isValid() {
		return $this->getTarget() != null;
	}

	/**
	 * Update the timestamp on autoblocks.
	 */
	public function updateTimestamp() {
		if ( $this->mAuto ) {
			$this->mTimestamp = wfTimestamp();
			$this->mExpiry = self::getAutoblockExpiry( $this->mTimestamp );

			$dbw = wfGetDB( DB_MASTER );
			$dbw->update( 'ipblocks',
				[ /* SET */
					'ipb_timestamp' => $dbw->timestamp( $this->mTimestamp ),
					'ipb_expiry' => $dbw->timestamp( $this->mExpiry ),
				],
				[ /* WHERE */
					'ipb_id' => $this->getId(),
				],
				__METHOD__
			);
		}
	}

	/**
	 * Get the IP address at the start of the range in Hex form
	 * @throws MWException
	 * @return string IP in Hex form
	 */
	public function getRangeStart() {
		switch ( $this->type ) {
			case self::TYPE_USER:
				return '';
			case self::TYPE_IP:
				return IP::toHex( $this->target );
			case self::TYPE_RANGE:
				list( $start, /*...*/ ) = IP::parseRange( $this->target );
				return $start;
			default:
				throw new MWException( "Block with invalid type" );
		}
	}

	/**
	 * Get the IP address at the end of the range in Hex form
	 * @throws MWException
	 * @return string IP in Hex form
	 */
	public function getRangeEnd() {
		switch ( $this->type ) {
			case self::TYPE_USER:
				return '';
			case self::TYPE_IP:
				return IP::toHex( $this->target );
			case self::TYPE_RANGE:
				list( /*...*/, $end ) = IP::parseRange( $this->target );
				return $end;
			default:
				throw new MWException( "Block with invalid type" );
		}
	}

	/**
	 * Get the user id of the blocking sysop
	 *
	 * @return int (0 for foreign users)
	 */
	public function getBy() {
		$blocker = $this->getBlocker();
		return ( $blocker instanceof User )
			? $blocker->getId()
			: 0;
	}

	/**
	 * Get the username of the blocking sysop
	 *
	 * @return string
	 */
	public function getByName() {
		$blocker = $this->getBlocker();
		return ( $blocker instanceof User )
			? $blocker->getName()
			: (string)$blocker; // username
	}

	/**
	 * Get the block ID
	 * @return int
	 */
	public function getId() {
		return $this->mId;
	}

	/**
	 * Get the system block type, if any
	 * @since 1.29
	 * @return string|null
	 */
	public function getSystemBlockType() {
		return $this->systemBlockType;
	}

	/**
	 * Get/set a flag determining whether the master is used for reads
	 *
	 * @param bool|null $x
	 * @return bool
	 */
	public function fromMaster( $x = null ) {
		return wfSetVar( $this->mFromMaster, $x );
	}

	/**
	 * Get/set whether the Block is a hardblock (affects logged-in users on a given IP/range)
	 * @param bool|null $x
	 * @return bool
	 */
	public function isHardblock( $x = null ) {
		wfSetVar( $this->isHardblock, $x );

		# You can't *not* hardblock a user
		return $this->getType() == self::TYPE_USER
			? true
			: $this->isHardblock;
	}

	/**
	 * @param null|bool $x
	 * @return bool
	 */
	public function isAutoblocking( $x = null ) {
		wfSetVar( $this->isAutoblocking, $x );

		# You can't put an autoblock on an IP or range as we don't have any history to
		# look over to get more IPs from
		return $this->getType() == self::TYPE_USER
			? $this->isAutoblocking
			: false;
	}

	/**
	 * Get/set whether the Block prevents a given action
	 *
	 * @param string $action Action to check
	 * @param bool|null $x Value for set, or null to just get value
	 * @return bool|null Null for unrecognized rights.
	 */
	public function prevents( $action, $x = null ) {
		global $wgBlockDisablesLogin;
		$res = null;
		switch ( $action ) {
			case 'edit':
				# For now... <evil laugh>
				$res = true;
				break;
			case 'createaccount':
				$res = wfSetVar( $this->mCreateAccount, $x );
				break;
			case 'sendemail':
				$res = wfSetVar( $this->mBlockEmail, $x );
				break;
			case 'editownusertalk':
				$res = wfSetVar( $this->mDisableUsertalk, $x );
				break;
			case 'read':
				$res = false;
				break;
		}
		if ( !$res && $wgBlockDisablesLogin ) {
			// If a block would disable login, then it should
			// prevent any action that all users cannot do
			$anon = new User;
			$res = $anon->isAllowed( $action ) ? $res : true;
		}

		return $res;
	}

	/**
	 * Get the block name, but with autoblocked IPs hidden as per standard privacy policy
	 * @return string Text is escaped
	 */
	public function getRedactedName() {
		if ( $this->mAuto ) {
			return Html::rawElement(
				'span',
				[ 'class' => 'mw-autoblockid' ],
				wfMessage( 'autoblockid', $this->mId )
			);
		} else {
			return htmlspecialchars( $this->getTarget() );
		}
	}

	/**
	 * Get a timestamp of the expiry for autoblocks
	 *
	 * @param string|int $timestamp
	 * @return string
	 */
	public static function getAutoblockExpiry( $timestamp ) {
		global $wgAutoblockExpiry;

		return wfTimestamp( TS_MW, wfTimestamp( TS_UNIX, $timestamp ) + $wgAutoblockExpiry );
	}

	/**
	 * Purge expired blocks from the ipblocks table
	 */
	public static function purgeExpired() {
		if ( wfReadOnly() ) {
			return;
		}

		DeferredUpdates::addUpdate( new AtomicSectionUpdate(
			wfGetDB( DB_MASTER ),
			__METHOD__,
			function ( IDatabase $dbw, $fname ) {
				$dbw->delete(
					'ipblocks',
					[ 'ipb_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ],
					$fname
				);
			}
		) );
	}

	/**
	 * Given a target and the target's type, get an existing Block object if possible.
	 * @param string|User|int $specificTarget A block target, which may be one of several types:
	 *     * A user to block, in which case $target will be a User
	 *     * An IP to block, in which case $target will be a User generated by using
	 *       User::newFromName( $ip, false ) to turn off name validation
	 *     * An IP range, in which case $target will be a String "123.123.123.123/18" etc
	 *     * The ID of an existing block, in the format "#12345" (since pure numbers are valid
	 *       usernames
	 *     Calling this with a user, IP address or range will not select autoblocks, and will
	 *     only select a block where the targets match exactly (so looking for blocks on
	 *     1.2.3.4 will not select 1.2.0.0/16 or even 1.2.3.4/32)
	 * @param string|User|int $vagueTarget As above, but we will search for *any* block which
	 *     affects that target (so for an IP address, get ranges containing that IP; and also
	 *     get any relevant autoblocks). Leave empty or blank to skip IP-based lookups.
	 * @param bool $fromMaster Whether to use the DB_MASTER database
	 * @return Block|null (null if no relevant block could be found).  The target and type
	 *     of the returned Block will refer to the actual block which was found, which might
	 *     not be the same as the target you gave if you used $vagueTarget!
	 */
	public static function newFromTarget( $specificTarget, $vagueTarget = null, $fromMaster = false ) {
		list( $target, $type ) = self::parseTarget( $specificTarget );
		if ( $type == self::TYPE_ID || $type == self::TYPE_AUTO ) {
			return self::newFromID( $target );

		} elseif ( $target === null && $vagueTarget == '' ) {
			# We're not going to find anything useful here
			# Be aware that the == '' check is explicit, since empty values will be
			# passed by some callers (T31116)
			return null;

		} elseif ( in_array(
			$type,
			[ self::TYPE_USER, self::TYPE_IP, self::TYPE_RANGE, null ] )
		) {
			$block = new Block();
			$block->fromMaster( $fromMaster );

			if ( $type !== null ) {
				$block->setTarget( $target );
			}

			if ( $block->newLoad( $vagueTarget ) ) {
				return $block;
			}
		}
		return null;
	}

	/**
	 * Get all blocks that match any IP from an array of IP addresses
	 *
	 * @param array $ipChain List of IPs (strings), usually retrieved from the
	 *     X-Forwarded-For header of the request
	 * @param bool $isAnon Exclude anonymous-only blocks if false
	 * @param bool $fromMaster Whether to query the master or replica DB
	 * @return array Array of Blocks
	 * @since 1.22
	 */
	public static function getBlocksForIPList( array $ipChain, $isAnon, $fromMaster = false ) {
		if ( !count( $ipChain ) ) {
			return [];
		}

		$conds = [];
		$proxyLookup = MediaWikiServices::getInstance()->getProxyLookup();
		foreach ( array_unique( $ipChain ) as $ipaddr ) {
			# Discard invalid IP addresses. Since XFF can be spoofed and we do not
			# necessarily trust the header given to us, make sure that we are only
			# checking for blocks on well-formatted IP addresses (IPv4 and IPv6).
			# Do not treat private IP spaces as special as it may be desirable for wikis
			# to block those IP ranges in order to stop misbehaving proxies that spoof XFF.
			if ( !IP::isValid( $ipaddr ) ) {
				continue;
			}
			# Don't check trusted IPs (includes local squids which will be in every request)
			if ( $proxyLookup->isTrustedProxy( $ipaddr ) ) {
				continue;
			}
			# Check both the original IP (to check against single blocks), as well as build
			# the clause to check for rangeblocks for the given IP.
			$conds['ipb_address'][] = $ipaddr;
			$conds[] = self::getRangeCond( IP::toHex( $ipaddr ) );
		}

		if ( !count( $conds ) ) {
			return [];
		}

		if ( $fromMaster ) {
			$db = wfGetDB( DB_MASTER );
		} else {
			$db = wfGetDB( DB_REPLICA );
		}
		$conds = $db->makeList( $conds, LIST_OR );
		if ( !$isAnon ) {
			$conds = [ $conds, 'ipb_anon_only' => 0 ];
		}
		$selectFields = array_merge(
			[ 'ipb_range_start', 'ipb_range_end' ],
			self::selectFields()
		);
		$rows = $db->select( 'ipblocks',
			$selectFields,
			$conds,
			__METHOD__
		);

		$blocks = [];
		foreach ( $rows as $row ) {
			$block = self::newFromRow( $row );
			if ( !$block->isExpired() ) {
				$blocks[] = $block;
			}
		}

		return $blocks;
	}

	/**
	 * From a list of multiple blocks, find the most exact and strongest Block.
	 *
	 * The logic for finding the "best" block is:
	 *  - Blocks that match the block's target IP are preferred over ones in a range
	 *  - Hardblocks are chosen over softblocks that prevent account creation
	 *  - Softblocks that prevent account creation are chosen over other softblocks
	 *  - Other softblocks are chosen over autoblocks
	 *  - If there are multiple exact or range blocks at the same level, the one chosen
	 *    is random
	 * This should be used when $blocks where retrieved from the user's IP address
	 * and $ipChain is populated from the same IP address information.
	 *
	 * @param array $blocks Array of Block objects
	 * @param array $ipChain List of IPs (strings). This is used to determine how "close"
	 *     a block is to the server, and if a block matches exactly, or is in a range.
	 *     The order is furthest from the server to nearest e.g., (Browser, proxy1, proxy2,
	 *     local-squid, ...)
	 * @throws MWException
	 * @return Block|null The "best" block from the list
	 */
	public static function chooseBlock( array $blocks, array $ipChain ) {
		if ( !count( $blocks ) ) {
			return null;
		} elseif ( count( $blocks ) == 1 ) {
			return $blocks[0];
		}

		// Sort hard blocks before soft ones and secondarily sort blocks
		// that disable account creation before those that don't.
		usort( $blocks, function ( Block $a, Block $b ) {
			$aWeight = (int)$a->isHardblock() . (int)$a->prevents( 'createaccount' );
			$bWeight = (int)$b->isHardblock() . (int)$b->prevents( 'createaccount' );
			return strcmp( $bWeight, $aWeight ); // highest weight first
		} );

		$blocksListExact = [
			'hard' => false,
			'disable_create' => false,
			'other' => false,
			'auto' => false
		];
		$blocksListRange = [
			'hard' => false,
			'disable_create' => false,
			'other' => false,
			'auto' => false
		];
		$ipChain = array_reverse( $ipChain );

		/** @var Block $block */
		foreach ( $blocks as $block ) {
			// Stop searching if we have already have a "better" block. This
			// is why the order of the blocks matters
			if ( !$block->isHardblock() && $blocksListExact['hard'] ) {
				break;
			} elseif ( !$block->prevents( 'createaccount' ) && $blocksListExact['disable_create'] ) {
				break;
			}

			foreach ( $ipChain as $checkip ) {
				$checkipHex = IP::toHex( $checkip );
				if ( (string)$block->getTarget() === $checkip ) {
					if ( $block->isHardblock() ) {
						$blocksListExact['hard'] = $blocksListExact['hard'] ?: $block;
					} elseif ( $block->prevents( 'createaccount' ) ) {
						$blocksListExact['disable_create'] = $blocksListExact['disable_create'] ?: $block;
					} elseif ( $block->mAuto ) {
						$blocksListExact['auto'] = $blocksListExact['auto'] ?: $block;
					} else {
						$blocksListExact['other'] = $blocksListExact['other'] ?: $block;
					}
					// We found closest exact match in the ip list, so go to the next Block
					break;
				} elseif ( array_filter( $blocksListExact ) == []
					&& $block->getRangeStart() <= $checkipHex
					&& $block->getRangeEnd() >= $checkipHex
				) {
					if ( $block->isHardblock() ) {
						$blocksListRange['hard'] = $blocksListRange['hard'] ?: $block;
					} elseif ( $block->prevents( 'createaccount' ) ) {
						$blocksListRange['disable_create'] = $blocksListRange['disable_create'] ?: $block;
					} elseif ( $block->mAuto ) {
						$blocksListRange['auto'] = $blocksListRange['auto'] ?: $block;
					} else {
						$blocksListRange['other'] = $blocksListRange['other'] ?: $block;
					}
					break;
				}
			}
		}

		if ( array_filter( $blocksListExact ) == [] ) {
			$blocksList = &$blocksListRange;
		} else {
			$blocksList = &$blocksListExact;
		}

		$chosenBlock = null;
		if ( $blocksList['hard'] ) {
			$chosenBlock = $blocksList['hard'];
		} elseif ( $blocksList['disable_create'] ) {
			$chosenBlock = $blocksList['disable_create'];
		} elseif ( $blocksList['other'] ) {
			$chosenBlock = $blocksList['other'];
		} elseif ( $blocksList['auto'] ) {
			$chosenBlock = $blocksList['auto'];
		} else {
			throw new MWException( "Proxy block found, but couldn't be classified." );
		}

		return $chosenBlock;
	}

	/**
	 * From an existing Block, get the target and the type of target.
	 * Note that, except for null, it is always safe to treat the target
	 * as a string; for User objects this will return User::__toString()
	 * which in turn gives User::getName().
	 *
	 * @param string|int|User|null $target
	 * @return array [ User|String|null, Block::TYPE_ constant|null ]
	 */
	public static function parseTarget( $target ) {
		# We may have been through this before
		if ( $target instanceof User ) {
			if ( IP::isValid( $target->getName() ) ) {
				return [ $target, self::TYPE_IP ];
			} else {
				return [ $target, self::TYPE_USER ];
			}
		} elseif ( $target === null ) {
			return [ null, null ];
		}

		$target = trim( $target );

		if ( IP::isValid( $target ) ) {
			# We can still create a User if it's an IP address, but we need to turn
			# off validation checking (which would exclude IP addresses)
			return [
				User::newFromName( IP::sanitizeIP( $target ), false ),
				self::TYPE_IP
			];

		} elseif ( IP::isValidRange( $target ) ) {
			# Can't create a User from an IP range
			return [ IP::sanitizeRange( $target ), self::TYPE_RANGE ];
		}

		# Consider the possibility that this is not a username at all
		# but actually an old subpage (bug #29797)
		if ( strpos( $target, '/' ) !== false ) {
			# An old subpage, drill down to the user behind it
			$target = explode( '/', $target )[0];
		}

		$userObj = User::newFromName( $target );
		if ( $userObj instanceof User ) {
			# Note that since numbers are valid usernames, a $target of "12345" will be
			# considered a User.  If you want to pass a block ID, prepend a hash "#12345",
			# since hash characters are not valid in usernames or titles generally.
			return [ $userObj, self::TYPE_USER ];

		} elseif ( preg_match( '/^#\d+$/', $target ) ) {
			# Autoblock reference in the form "#12345"
			return [ substr( $target, 1 ), self::TYPE_AUTO ];

		} else {
			# WTF?
			return [ null, null ];
		}
	}

	/**
	 * Get the type of target for this particular block
	 * @return int Block::TYPE_ constant, will never be TYPE_ID
	 */
	public function getType() {
		return $this->mAuto
			? self::TYPE_AUTO
			: $this->type;
	}

	/**
	 * Get the target and target type for this particular Block.  Note that for autoblocks,
	 * this returns the unredacted name; frontend functions need to call $block->getRedactedName()
	 * in this situation.
	 * @return array [ User|String, Block::TYPE_ constant ]
	 * @todo FIXME: This should be an integral part of the Block member variables
	 */
	public function getTargetAndType() {
		return [ $this->getTarget(), $this->getType() ];
	}

	/**
	 * Get the target for this particular Block.  Note that for autoblocks,
	 * this returns the unredacted name; frontend functions need to call $block->getRedactedName()
	 * in this situation.
	 * @return User|string
	 */
	public function getTarget() {
		return $this->target;
	}

	/**
	 * @since 1.19
	 *
	 * @return mixed|string
	 */
	public function getExpiry() {
		return $this->mExpiry;
	}

	/**
	 * Set the target for this block, and update $this->type accordingly
	 * @param mixed $target
	 */
	public function setTarget( $target ) {
		list( $this->target, $this->type ) = self::parseTarget( $target );
	}

	/**
	 * Get the user who implemented this block
	 * @return User|string Local User object or string for a foreign user
	 */
	public function getBlocker() {
		return $this->blocker;
	}

	/**
	 * Set the user who implemented (or will implement) this block
	 * @param User|string $user Local User object or username string for foreign users
	 */
	public function setBlocker( $user ) {
		$this->blocker = $user;
	}

	/**
	 * Set the 'BlockID' cookie to this block's ID and expiry time. The cookie's expiry will be
	 * the same as the block's, to a maximum of 24 hours.
	 *
	 * @since 1.29
	 *
	 * @param WebResponse $response The response on which to set the cookie.
	 */
	public function setCookie( WebResponse $response ) {
		// Calculate the default expiry time.
		$maxExpiryTime = wfTimestamp( TS_MW, wfTimestamp() + ( 24 * 60 * 60 ) );

		// Use the Block's expiry time only if it's less than the default.
		$expiryTime = $this->getExpiry();
		if ( $expiryTime === 'infinity' || $expiryTime > $maxExpiryTime ) {
			$expiryTime = $maxExpiryTime;
		}

		// Set the cookie. Reformat the MediaWiki datetime as a Unix timestamp for the cookie.
		$expiryValue = DateTime::createFromFormat( 'YmdHis', $expiryTime )->format( 'U' );
		$cookieOptions = [ 'httpOnly' => false ];
		$cookieValue = $this->getCookieValue();
		$response->setCookie( 'BlockID', $cookieValue, $expiryValue, $cookieOptions );
	}

	/**
	 * Unset the 'BlockID' cookie.
	 *
	 * @since 1.29
	 *
	 * @param WebResponse $response The response on which to unset the cookie.
	 */
	public static function clearCookie( WebResponse $response ) {
		$response->clearCookie( 'BlockID', [ 'httpOnly' => false ] );
	}

	/**
	 * Get the BlockID cookie's value for this block. This is usually the block ID concatenated
	 * with an HMAC in order to avoid spoofing (T152951), but if wgSecretKey is not set will just
	 * be the block ID.
	 *
	 * @since 1.29
	 *
	 * @return string The block ID, probably concatenated with "!" and the HMAC.
	 */
	public function getCookieValue() {
		$config = RequestContext::getMain()->getConfig();
		$id = $this->getId();
		$secretKey = $config->get( 'SecretKey' );
		if ( !$secretKey ) {
			// If there's no secret key, don't append a HMAC.
			return $id;
		}
		$hmac = MWCryptHash::hmac( $id, $secretKey, false );
		$cookieValue = $id . '!' . $hmac;
		return $cookieValue;
	}

	/**
	 * Get the stored ID from the 'BlockID' cookie. The cookie's value is usually a combination of
	 * the ID and a HMAC (see Block::setCookie), but will sometimes only be the ID.
	 *
	 * @since 1.29
	 *
	 * @param string $cookieValue The string in which to find the ID.
	 *
	 * @return int|null The block ID, or null if the HMAC is present and invalid.
	 */
	public static function getIdFromCookieValue( $cookieValue ) {
		// Extract the ID prefix from the cookie value (may be the whole value, if no bang found).
		$bangPos = strpos( $cookieValue, '!' );
		$id = ( $bangPos === false ) ? $cookieValue : substr( $cookieValue, 0, $bangPos );
		// Get the site-wide secret key.
		$config = RequestContext::getMain()->getConfig();
		$secretKey = $config->get( 'SecretKey' );
		if ( !$secretKey ) {
			// If there's no secret key, just use the ID as given.
			return $id;
		}
		$storedHmac = substr( $cookieValue, $bangPos + 1 );
		$calculatedHmac = MWCryptHash::hmac( $id, $secretKey, false );
		if ( $calculatedHmac === $storedHmac ) {
			return $id;
		} else {
			return null;
		}
	}

	/**
	 * Get the key and parameters for the corresponding error message.
	 *
	 * @since 1.22
	 * @param IContextSource $context
	 * @return array
	 */
	public function getPermissionsError( IContextSource $context ) {
		$blocker = $this->getBlocker();
		if ( $blocker instanceof User ) { // local user
			$blockerUserpage = $blocker->getUserPage();
			$link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
		} else { // foreign user
			$link = $blocker;
		}

		$reason = $this->mReason;
		if ( $reason == '' ) {
			$reason = $context->msg( 'blockednoreason' )->text();
		}

		/* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
		 * This could be a username, an IP range, or a single IP. */
		$intended = $this->getTarget();

		$systemBlockType = $this->getSystemBlockType();

		$lang = $context->getLanguage();
		return [
			$systemBlockType !== null
				? 'systemblockedtext'
				: ( $this->mAuto ? 'autoblockedtext' : 'blockedtext' ),
			$link,
			$reason,
			$context->getRequest()->getIP(),
			$this->getByName(),
			$systemBlockType !== null ? $systemBlockType : $this->getId(),
			$lang->formatExpiry( $this->mExpiry ),
			(string)$intended,
			$lang->userTimeAndDate( $this->mTimestamp, $context->getUser() ),
		];
	}
}