BlockManager.php

Go to the documentation of this file.

<?php
namespace MediaWiki\Block;

use DateTime;
use DeferredUpdates;
use IP;
use MediaWiki\Config\ServiceOptions;
use MediaWiki\User\UserIdentity;
use MWCryptHash;
use User;
use WebRequest;
use WebResponse;
use Wikimedia\IPSet;

class BlockManager {
    // TODO: This should be UserIdentity instead of User
    private $currentUser;

    private $currentRequest;

    public static $constructorOptions = [
        'ApplyIpBlocksToXff',
        'CookieSetOnAutoblock',
        'CookieSetOnIpBlock',
        'DnsBlacklistUrls',
        'EnableDnsBlacklist',
        'ProxyList',
        'ProxyWhitelist',
        'SecretKey',
        'SoftBlockRanges',
    ];

    public function __construct(
        ServiceOptions $options,
        User $currentUser,
        WebRequest $currentRequest
    ) {
        $options->assertRequiredOptions( self::$constructorOptions );
        $this->options = $options;
        $this->currentUser = $currentUser;
        $this->currentRequest = $currentRequest;
    }

    public function getUserBlock( User $user, $fromReplica ) {
        $isAnon = $user->getId() === 0;

        // TODO: If $user is the current user, we should use the current request. Otherwise,
        // we should not look for XFF or cookie blocks.
        $request = $user->getRequest();

        # We only need to worry about passing the IP address to the block generator if the
        # user is not immune to autoblocks/hardblocks, and they are the current user so we
        # know which IP address they're actually coming from
        $ip = null;
        $sessionUser = $this->currentUser;
        // the session user is set up towards the end of Setup.php. Until then,
        // assume it's a logged-out user.
        $globalUserName = $sessionUser->isSafeToLoad()
            ? $sessionUser->getName()
            : IP::sanitizeIP( $this->currentRequest->getIP() );
        if ( $user->getName() === $globalUserName && !$user->isAllowed( 'ipblock-exempt' ) ) {
            $ip = $this->currentRequest->getIP();
        }

        // User/IP blocking
        // After this, $blocks is an array of blocks or an empty array
        // TODO: remove dependency on DatabaseBlock
        $blocks = DatabaseBlock::newListFromTarget( $user, $ip, !$fromReplica );

        // Cookie blocking
        $cookieBlock = $this->getBlockFromCookieValue( $user, $request );
        if ( $cookieBlock instanceof AbstractBlock ) {
            $blocks[] = $cookieBlock;
        }

        // Proxy blocking
        if ( $ip !== null && !in_array( $ip, $this->options->get( 'ProxyWhitelist' ) ) ) {
            // Local list
            if ( $this->isLocallyBlockedProxy( $ip ) ) {
                $blocks[] = new SystemBlock( [
                    'byText' => wfMessage( 'proxyblocker' )->text(),
                    'reason' => wfMessage( 'proxyblockreason' )->plain(),
                    'address' => $ip,
                    'systemBlock' => 'proxy',
                ] );
            } elseif ( $isAnon && $this->isDnsBlacklisted( $ip ) ) {
                $blocks[] = new SystemBlock( [
                    'byText' => wfMessage( 'sorbs' )->text(),
                    'reason' => wfMessage( 'sorbsreason' )->plain(),
                    'address' => $ip,
                    'systemBlock' => 'dnsbl',
                ] );
            }
        }

        // (T25343) Apply IP blocks to the contents of XFF headers, if enabled
        if ( $this->options->get( 'ApplyIpBlocksToXff' )
            && $ip !== null
            && !in_array( $ip, $this->options->get( 'ProxyWhitelist' ) )
        ) {
            $xff = $request->getHeader( 'X-Forwarded-For' );
            $xff = array_map( 'trim', explode( ',', $xff ) );
            $xff = array_diff( $xff, [ $ip ] );
            // TODO: remove dependency on DatabaseBlock
            $xffblocks = DatabaseBlock::getBlocksForIPList( $xff, $isAnon, !$fromReplica );
            $blocks = array_merge( $blocks, $xffblocks );
        }

        // Soft blocking
        if ( $ip !== null
            && $isAnon
            && IP::isInRanges( $ip, $this->options->get( 'SoftBlockRanges' ) )
        ) {
            $blocks[] = new SystemBlock( [
                'address' => $ip,
                'byText' => 'MediaWiki default',
                'reason' => wfMessage( 'softblockrangesreason', $ip )->plain(),
                'anonOnly' => true,
                'systemBlock' => 'wgSoftBlockRanges',
            ] );
        }

        // Filter out any duplicated blocks, e.g. from the cookie
        $blocks = $this->getUniqueBlocks( $blocks );

        if ( count( $blocks ) > 0 ) {
            if ( count( $blocks ) === 1 ) {
                $block = $blocks[ 0 ];
            } else {
                $block = new CompositeBlock( [
                    'address' => $ip,
                    'byText' => 'MediaWiki default',
                    'reason' => wfMessage( 'blockedtext-composite-reason' )->plain(),
                    'originalBlocks' => $blocks,
                ] );
            }
            return $block;
        }

        return null;
    }

    private function getUniqueBlocks( array $blocks ) {
        $systemBlocks = [];
        $databaseBlocks = [];

        foreach ( $blocks as $block ) {
            if ( $block instanceof SystemBlock ) {
                $systemBlocks[] = $block;
            } elseif ( $block->getType() === DatabaseBlock::TYPE_AUTO ) {
                if ( !isset( $databaseBlocks[$block->getParentBlockId()] ) ) {
                    $databaseBlocks[$block->getParentBlockId()] = $block;
                }
            } else {
                $databaseBlocks[$block->getId()] = $block;
            }
        }

        return array_merge( $systemBlocks, $databaseBlocks );
    }

    private function getBlockFromCookieValue(
        UserIdentity $user,
        WebRequest $request
    ) {
        $blockCookieId = $this->getIdFromCookieValue( $request->getCookie( 'BlockID' ) );

        if ( $blockCookieId !== null ) {
            // TODO: remove dependency on DatabaseBlock
            $block = DatabaseBlock::newFromID( $blockCookieId );
            if (
                $block instanceof DatabaseBlock &&
                $this->shouldApplyCookieBlock( $block, $user->isAnon() )
            ) {
                return $block;
            }
            $this->clearBlockCookie( $request->response() );
        }

        return false;
    }

    private function shouldApplyCookieBlock( DatabaseBlock $block, $isAnon ) {
        if ( !$block->isExpired() ) {
            switch ( $block->getType() ) {
                case DatabaseBlock::TYPE_IP:
                case DatabaseBlock::TYPE_RANGE:
                    // If block is type IP or IP range, load only
                    // if user is not logged in (T152462)
                    return $isAnon &&
                        $this->options->get( 'CookieSetOnIpBlock' );
                case DatabaseBlock::TYPE_USER:
                    return $block->isAutoblocking() &&
                        $this->options->get( 'CookieSetOnAutoblock' );
                default:
                    return false;
            }
        }
        return false;
    }

    private function isLocallyBlockedProxy( $ip ) {
        $proxyList = $this->options->get( 'ProxyList' );
        if ( !$proxyList ) {
            return false;
        }

        if ( !is_array( $proxyList ) ) {
            // Load values from the specified file
            $proxyList = array_map( 'trim', file( $proxyList ) );
        }

        $resultProxyList = [];
        $deprecatedIPEntries = [];

        // backward compatibility: move all ip addresses in keys to values
        foreach ( $proxyList as $key => $value ) {
            $keyIsIP = IP::isIPAddress( $key );
            $valueIsIP = IP::isIPAddress( $value );
            if ( $keyIsIP && !$valueIsIP ) {
                $deprecatedIPEntries[] = $key;
                $resultProxyList[] = $key;
            } elseif ( $keyIsIP && $valueIsIP ) {
                $deprecatedIPEntries[] = $key;
                $resultProxyList[] = $key;
                $resultProxyList[] = $value;
            } else {
                $resultProxyList[] = $value;
            }
        }

        if ( $deprecatedIPEntries ) {
            wfDeprecated(
                'IP addresses in the keys of $wgProxyList (found the following IP addresses in keys: ' .
                implode( ', ', $deprecatedIPEntries ) . ', please move them to values)', '1.30' );
        }

        $proxyListIPSet = new IPSet( $resultProxyList );
        return $proxyListIPSet->match( $ip );
    }

    public function isDnsBlacklisted( $ip, $checkWhitelist = false ) {
        if ( !$this->options->get( 'EnableDnsBlacklist' ) ||
            ( $checkWhitelist && in_array( $ip, $this->options->get( 'ProxyWhitelist' ) ) )
        ) {
            return false;
        }

        return $this->inDnsBlacklist( $ip, $this->options->get( 'DnsBlacklistUrls' ) );
    }

    private function inDnsBlacklist( $ip, array $bases ) {
        $found = false;
        // @todo FIXME: IPv6 ???  (https://bugs.php.net/bug.php?id=33170)
        if ( IP::isIPv4( $ip ) ) {
            // Reverse IP, T23255
            $ipReversed = implode( '.', array_reverse( explode( '.', $ip ) ) );

            foreach ( $bases as $base ) {
                // Make hostname
                // If we have an access key, use that too (ProjectHoneypot, etc.)
                $basename = $base;
                if ( is_array( $base ) ) {
                    if ( count( $base ) >= 2 ) {
                        // Access key is 1, base URL is 0
                        $hostname = "{$base[1]}.$ipReversed.{$base[0]}";
                    } else {
                        $hostname = "$ipReversed.{$base[0]}";
                    }
                    $basename = $base[0];
                } else {
                    $hostname = "$ipReversed.$base";
                }

                // Send query
                $ipList = $this->checkHost( $hostname );

                if ( $ipList ) {
                    wfDebugLog(
                        'dnsblacklist',
                        "Hostname $hostname is {$ipList[0]}, it's a proxy says $basename!"
                    );
                    $found = true;
                    break;
                }

                wfDebugLog( 'dnsblacklist', "Requested $hostname, not found in $basename." );
            }
        }

        return $found;
    }

    protected function checkHost( $hostname ) {
        return gethostbynamel( $hostname );
    }

    public function trackBlockWithCookie( User $user ) {
        $request = $user->getRequest();
        if ( $request->getCookie( 'BlockID' ) !== null ) {
            // User already has a block cookie
            return;
        }

        // Defer checks until the user has been fully loaded to avoid circular dependency
        // of User on itself (T180050 and T226777)
        DeferredUpdates::addCallableUpdate(
            function () use ( $user, $request ) {
                $block = $user->getBlock();
                $response = $request->response();
                $isAnon = $user->isAnon();

                if ( $block ) {
                    if ( $block instanceof CompositeBlock ) {
                        // TODO: Improve on simply tracking the first trackable block (T225654)
                        foreach ( $block->getOriginalBlocks() as $originalBlock ) {
                            if ( $this->shouldTrackBlockWithCookie( $originalBlock, $isAnon ) ) {
                                $this->setBlockCookie( $originalBlock, $response );
                                return;
                            }
                        }
                    } else {
                        if ( $this->shouldTrackBlockWithCookie( $block, $isAnon ) ) {
                            $this->setBlockCookie( $block, $response );
                        }
                    }
                }
            },
            DeferredUpdates::PRESEND
        );
    }

    public function setBlockCookie( DatabaseBlock $block, 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 = $block->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( $block );
        $response->setCookie( 'BlockID', $cookieValue, $expiryValue, $cookieOptions );
    }

    private function shouldTrackBlockWithCookie( AbstractBlock $block, $isAnon ) {
        if ( $block instanceof DatabaseBlock ) {
            switch ( $block->getType() ) {
                case DatabaseBlock::TYPE_IP:
                case DatabaseBlock::TYPE_RANGE:
                    return $isAnon && $this->options->get( 'CookieSetOnIpBlock' );
                case DatabaseBlock::TYPE_USER:
                    return !$isAnon &&
                        $this->options->get( 'CookieSetOnAutoblock' ) &&
                        $block->isAutoblocking();
                default:
                    return false;
            }
        }
        return false;
    }

    public static function clearBlockCookie( WebResponse $response ) {
        $response->clearCookie( 'BlockID', [ 'httpOnly' => false ] );
    }

    public function getIdFromCookieValue( $cookieValue ) {
        // The cookie value must start with a number
        if ( !is_numeric( substr( $cookieValue, 0, 1 ) ) ) {
            return null;
        }

        // 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, $bangPos );
        if ( !$this->options->get( 'SecretKey' ) ) {
            // If there's no secret key, just use the ID as given.
            return $id;
        }
        $storedHmac = substr( $cookieValue, $bangPos + 1 );
        $calculatedHmac = MWCryptHash::hmac( $id, $this->options->get( 'SecretKey' ), false );
        if ( $calculatedHmac === $storedHmac ) {
            return $id;
        } else {
            return null;
        }
    }

    public function getCookieValue( DatabaseBlock $block ) {
        $id = $block->getId();
        if ( !$this->options->get( 'SecretKey' ) ) {
            // If there's no secret key, don't append a HMAC.
            return $id;
        }
        $hmac = MWCryptHash::hmac( $id, $this->options->get( 'SecretKey' ), false );
        $cookieValue = $id . '!' . $hmac;
        return $cookieValue;
    }

}