BlockManager.php

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<?php
namespace MediaWiki\Block;
 
use LogicException;
use MediaWiki\Config\ServiceOptions;
use MediaWiki\HookContainer\HookContainer;
use MediaWiki\HookContainer\HookRunner;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\Message\Message;
use MediaWiki\Request\ProxyLookup;
use MediaWiki\Request\WebRequest;
use MediaWiki\Request\WebResponse;
use MediaWiki\User\User;
use MediaWiki\User\UserFactory;
use MediaWiki\User\UserIdentity;
use MediaWiki\User\UserIdentityUtils;
use MWCryptHash;
use Psr\Log\LoggerInterface;
use Wikimedia\IPSet;
use Wikimedia\IPUtils;
 
class BlockManager {
    public const CONSTRUCTOR_OPTIONS = [
        MainConfigNames::ApplyIpBlocksToXff,
        MainConfigNames::CookieSetOnAutoblock,
        MainConfigNames::CookieSetOnIpBlock,
        MainConfigNames::DnsBlacklistUrls,
        MainConfigNames::EnableDnsBlacklist,
        MainConfigNames::ProxyList,
        MainConfigNames::ProxyWhitelist,
        MainConfigNames::SecretKey,
        MainConfigNames::SoftBlockRanges,
    ];
 
    private ServiceOptions $options;
    private UserFactory $userFactory;
    private UserIdentityUtils $userIdentityUtils;
    private LoggerInterface $logger;
    private HookRunner $hookRunner;
    private DatabaseBlockStore $blockStore;
    private ProxyLookup $proxyLookup;
 
    private BlockCache $userBlockCache;
    private BlockCache $createAccountBlockCache;
 
    public function __construct(
        ServiceOptions $options,
        UserFactory $userFactory,
        UserIdentityUtils $userIdentityUtils,
        LoggerInterface $logger,
        HookContainer $hookContainer,
        DatabaseBlockStore $blockStore,
        ProxyLookup $proxyLookup
    ) {
        $options->assertRequiredOptions( self::CONSTRUCTOR_OPTIONS );
        $this->options = $options;
        $this->userFactory = $userFactory;
        $this->userIdentityUtils = $userIdentityUtils;
        $this->logger = $logger;
        $this->hookRunner = new HookRunner( $hookContainer );
        $this->blockStore = $blockStore;
        $this->proxyLookup = $proxyLookup;
 
        $this->userBlockCache = new BlockCache;
        $this->createAccountBlockCache = new BlockCache;
    }
 
    public function getUserBlock(
        UserIdentity $user,
        $request,
        $fromReplica,
        $disableIpBlockExemptChecking = false
    ) {
        // If this is the global user, they may be affected by IP blocks (case #1),
        // or they may be exempt (case #2). If affected, look for additional blocks
        // against the IP address and referenced in a cookie.
        $checkIpBlocks = $request &&
            // Because calling getBlock within Autopromote leads back to here,
            // thus causing a infinite recursion. We fix this by not checking for
            // ipblock-exempt when calling getBlock within Autopromote.
            // See T270145.
            !$disableIpBlockExemptChecking &&
            !$this->isIpBlockExempt( $user );
 
        return $this->getBlock(
            $user,
            $checkIpBlocks ? $request : null,
            $fromReplica
        );
    }
 
    public function getBlock(
        UserIdentity $user,
        ?WebRequest $request,
        $fromReplica = true
    ): ?AbstractBlock {
        $fromPrimary = !$fromReplica;
        $ip = null;
 
        // TODO: normalise the fromPrimary parameter when replication is not configured.
        // Maybe DatabaseBlockStore can tell us about the LoadBalancer configuration.
        $cacheKey = new BlockCacheKey(
            $request,
            $user,
            $fromPrimary
        );
        $block = $this->userBlockCache->get( $cacheKey );
        if ( $block !== null ) {
            $this->logger->debug( "Block cache hit with key {$cacheKey}" );
            return $block ?: null;
        }
        $this->logger->debug( "Block cache miss with key {$cacheKey}" );
 
        if ( $request ) {
 
            // Case #1: checking the global user, including IP blocks
            $ip = $request->getIP();
            // For soft blocks, i.e. blocks that don't block logged-in users,
            // temporary users are treated as anon users, and are blocked.
            $applySoftBlocks = !$this->userIdentityUtils->isNamed( $user );
 
            $xff = $request->getHeader( 'X-Forwarded-For' );
 
            $blocks = array_merge(
                $this->blockStore->newListFromTarget( $user, $ip, $fromPrimary ),
                $this->getSystemIpBlocks( $ip, $applySoftBlocks ),
                $this->getXffBlocks( $ip, $xff, $applySoftBlocks, $fromPrimary ),
                $this->getCookieBlock( $user, $request )
            );
        } else {
 
            // Case #2: checking the global user, but they are exempt from IP blocks
            // and cookie blocks, so we only check for a user account block.
            // Case #3: checking whether another user's account is blocked.
            $blocks = $this->blockStore->newListFromTarget( $user, null, $fromPrimary );
 
        }
 
        $block = $this->createGetBlockResult( $ip, $blocks );
 
        $legacyUser = $this->userFactory->newFromUserIdentity( $user );
        $this->hookRunner->onGetUserBlock( clone $legacyUser, $ip, $block );
 
        $this->userBlockCache->set( $cacheKey, $block ?: false );
        return $block;
    }
 
    public function clearUserCache( UserIdentity $user ) {
        $this->userBlockCache->clearUser( $user );
        $this->createAccountBlockCache->clearUser( $user );
    }
 
    public function getCreateAccountBlock(
        UserIdentity $user,
        ?WebRequest $request,
        $fromReplica
    ) {
        $key = new BlockCacheKey( $request, $user, $fromReplica );
        $cachedBlock = $this->createAccountBlockCache->get( $key );
        if ( $cachedBlock !== null ) {
            $this->logger->debug( "Create account block cache hit with key {$key}" );
            return $cachedBlock ?: null;
        }
        $this->logger->debug( "Create account block cache miss with key {$key}" );
 
        $applicableBlocks = [];
        $userBlock = $this->getBlock( $user, $request, $fromReplica );
        if ( $userBlock ) {
            $applicableBlocks = $userBlock->toArray();
        }
 
        // T15611: if the IP address the user is trying to create an account from is
        // blocked with createaccount disabled, prevent new account creation there even
        // when the user is logged in
        if ( $request ) {
            $ipBlock = $this->blockStore->newFromTarget(
                null, $request->getIP()
            );
            if ( $ipBlock ) {
                $applicableBlocks = array_merge( $applicableBlocks, $ipBlock->toArray() );
            }
        }
 
        foreach ( $applicableBlocks as $i => $block ) {
            if ( !$block->appliesToRight( 'createaccount' ) ) {
                unset( $applicableBlocks[$i] );
            }
        }
        $result = $this->createGetBlockResult(
            $request ? $request->getIP() : null,
            $applicableBlocks
        );
        $this->createAccountBlockCache->set( $key, $result ?: false );
        return $result;
    }
 
    public function filter( ?Block $block, $callback ) {
        if ( !$block ) {
            return null;
        } elseif ( $block instanceof CompositeBlock ) {
            $blocks = $block->getOriginalBlocks();
            $originalCount = count( $blocks );
            foreach ( $blocks as $i => $originalBlock ) {
                if ( !$callback( $originalBlock ) ) {
                    unset( $blocks[$i] );
                }
            }
            if ( !$blocks ) {
                return null;
            } elseif ( count( $blocks ) === 1 ) {
                return $blocks[ array_key_first( $blocks ) ];
            } elseif ( count( $blocks ) === $originalCount ) {
                return $block;
            } else {
                return $block->withOriginalBlocks( array_values( $blocks ) );
            }
        } elseif ( !$callback( $block ) ) {
            return null;
        } else {
            return $block;
        }
    }
 
    private function isIpBlockExempt( UserIdentity $user ) {
        return MediaWikiServices::getInstance()->getPermissionManager()
            ->userHasRight( $user, 'ipblock-exempt' );
    }
 
    private function createGetBlockResult( ?string $ip, array $blocks ): ?AbstractBlock {
        // Filter out any duplicated blocks, e.g. from the cookie
        $blocks = $this->getUniqueBlocks( $blocks );
 
        if ( count( $blocks ) === 0 ) {
            return null;
        } elseif ( count( $blocks ) === 1 ) {
            return $blocks[ 0 ];
        } else {
            $compositeBlock = CompositeBlock::createFromBlocks( ...$blocks );
            $compositeBlock->setTarget( $ip );
            return $compositeBlock;
        }
    }
 
    public function getIpBlock( string $ip, bool $fromReplica ): ?AbstractBlock {
        if ( !IPUtils::isValid( $ip ) ) {
            return null;
        }
 
        $blocks = array_merge(
            $this->blockStore->newListFromTarget( $ip, $ip, !$fromReplica ),
            $this->getSystemIpBlocks( $ip, true )
        );
 
        return $this->createGetBlockResult( $ip, $blocks );
    }
 
    private function getCookieBlock( UserIdentity $user, WebRequest $request ): array {
        $cookieBlock = $this->getBlockFromCookieValue( $user, $request );
 
        return $cookieBlock instanceof DatabaseBlock ? [ $cookieBlock ] : [];
    }
 
    private function getSystemIpBlocks( string $ip, bool $applySoftBlocks ): array {
        $blocks = [];
 
        // Proxy blocking
        if ( !in_array( $ip, $this->options->get( MainConfigNames::ProxyWhitelist ) ) ) {
            // Local list
            if ( $this->isLocallyBlockedProxy( $ip ) ) {
                $blocks[] = new SystemBlock( [
                    'reason' => new Message( 'proxyblockreason' ),
                    'address' => $ip,
                    'systemBlock' => 'proxy',
                ] );
            } elseif ( $applySoftBlocks && $this->isDnsBlacklisted( $ip ) ) {
                $blocks[] = new SystemBlock( [
                    'reason' => new Message( 'sorbsreason' ),
                    'address' => $ip,
                    'anonOnly' => true,
                    'systemBlock' => 'dnsbl',
                ] );
            }
        }
 
        // Soft blocking
        if ( $applySoftBlocks && IPUtils::isInRanges( $ip, $this->options->get( MainConfigNames::SoftBlockRanges ) ) ) {
            $blocks[] = new SystemBlock( [
                'address' => $ip,
                'reason' => new Message( 'softblockrangesreason', [ $ip ] ),
                'anonOnly' => true,
                'systemBlock' => 'wgSoftBlockRanges',
            ] );
        }
 
        return $blocks;
    }
 
    private function getXffBlocks(
        string $ip,
        string $xff,
        bool $applySoftBlocks,
        bool $fromPrimary
    ): array {
        // (T25343) Apply IP blocks to the contents of XFF headers, if enabled
        if ( $this->options->get( MainConfigNames::ApplyIpBlocksToXff )
            && !in_array( $ip, $this->options->get( MainConfigNames::ProxyWhitelist ) )
        ) {
            $xff = array_map( 'trim', explode( ',', $xff ) );
            $xff = array_diff( $xff, [ $ip ] );
            $xffblocks = $this->getBlocksForIPList( $xff, $applySoftBlocks, $fromPrimary );
 
            // (T285159) Exclude autoblocks from XFF headers to prevent spoofed
            // headers uncovering the IPs of autoblocked users
            $xffblocks = array_filter( $xffblocks, static function ( $block ) {
                return $block->getType() !== Block::TYPE_AUTO;
            } );
 
            return $xffblocks;
        }
 
        return [];
    }
 
    public function getBlocksForIPList( array $ipChain, bool $applySoftBlocks, bool $fromPrimary ) {
        if ( $ipChain === [] ) {
            return [];
        }
 
        $ips = [];
        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 ( !IPUtils::isValid( $ipaddr ) ) {
                continue;
            }
            // Don't check trusted IPs (includes local CDNs which will be in every request)
            if ( $this->proxyLookup->isTrustedProxy( $ipaddr ) ) {
                continue;
            }
            $ips[] = $ipaddr;
        }
        return $this->blockStore->newListFromIPs( $ips, $applySoftBlocks, $fromPrimary );
    }
 
    private function getUniqueBlocks( array $blocks ) {
        $systemBlocks = [];
        $databaseBlocks = [];
 
        foreach ( $blocks as $block ) {
            if ( $block instanceof SystemBlock ) {
                $systemBlocks[] = $block;
            } elseif ( $block->getType() === DatabaseBlock::TYPE_AUTO ) {
                '@phan-var DatabaseBlock $block';
                if ( !isset( $databaseBlocks[$block->getParentBlockId()] ) ) {
                    $databaseBlocks[$block->getParentBlockId()] = $block;
                }
            } else {
                // @phan-suppress-next-line PhanTypeMismatchDimAssignment getId is not null here
                $databaseBlocks[$block->getId()] = $block;
            }
        }
 
        return array_values( array_merge( $systemBlocks, $databaseBlocks ) );
    }
 
    private function getBlockFromCookieValue(
        UserIdentity $user,
        WebRequest $request
    ) {
        $cookieValue = $request->getCookie( 'BlockID' );
        if ( $cookieValue === null ) {
            return false;
        }
 
        $blockCookieId = $this->getIdFromCookieValue( $cookieValue );
        if ( $blockCookieId !== null ) {
            $block = $this->blockStore->newFromID( $blockCookieId );
            if (
                $block instanceof DatabaseBlock &&
                $this->shouldApplyCookieBlock( $block, !$user->isRegistered() )
            ) {
                return $block;
            }
        }
 
        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( MainConfigNames::CookieSetOnIpBlock );
                case DatabaseBlock::TYPE_USER:
                    return $block->isAutoblocking() &&
                        $this->options->get( MainConfigNames::CookieSetOnAutoblock );
                default:
                    return false;
            }
        }
        return false;
    }
 
    private function isLocallyBlockedProxy( $ip ) {
        $proxyList = $this->options->get( MainConfigNames::ProxyList );
        if ( !$proxyList ) {
            return false;
        }
 
        if ( !is_array( $proxyList ) ) {
            // Load values from the specified file
            $proxyList = array_map( 'trim', file( $proxyList ) );
        }
 
        $proxyListIPSet = new IPSet( $proxyList );
        return $proxyListIPSet->match( $ip );
    }
 
    public function isDnsBlacklisted( $ip, $checkAllowed = false ) {
        if ( !$this->options->get( MainConfigNames::EnableDnsBlacklist ) ||
            ( $checkAllowed && in_array( $ip, $this->options->get( MainConfigNames::ProxyWhitelist ) ) )
        ) {
            return false;
        }
 
        return $this->inDnsBlacklist( $ip, $this->options->get( MainConfigNames::DnsBlacklistUrls ) );
    }
 
    private function inDnsBlacklist( $ip, array $bases ) {
        $found = false;
        // @todo FIXME: IPv6 ???  (https://bugs.php.net/bug.php?id=33170)
        if ( IPUtils::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 ) {
                    $this->logger->info(
                        'Hostname {hostname} is {ipList}, it\'s a proxy says {basename}!',
                        [
                            'hostname' => $hostname,
                            'ipList' => $ipList[0],
                            'basename' => $basename,
                        ]
                    );
                    $found = true;
                    break;
                }
 
                $this->logger->debug( "Requested $hostname, not found in $basename." );
            }
        }
 
        return $found;
    }
 
    protected function checkHost( $hostname ) {
        return gethostbynamel( $hostname );
    }
 
    public function trackBlockWithCookie( User $user, WebResponse $response ) {
        if ( !$this->options->get( MainConfigNames::CookieSetOnIpBlock ) &&
            !$this->options->get( MainConfigNames::CookieSetOnAutoblock ) ) {
            // Cookie blocks are disabled, return early to prevent executing unnecessary logic.
            return;
        }
 
        $request = $user->getRequest();
 
        if ( $request->getCookie( 'BlockID' ) !== null ) {
            $cookieBlock = $this->getBlockFromCookieValue( $user, $request );
            if ( $cookieBlock && $this->shouldApplyCookieBlock( $cookieBlock, $user->isAnon() ) ) {
                return;
            }
            // The block pointed to by the cookie is invalid or should not be tracked.
            $this->clearBlockCookie( $response );
        }
 
        if ( !$user->isSafeToLoad() ) {
            // Prevent a circular dependency by not allowing this method to be called
            // before or while the user is being loaded.
            // E.g. User > BlockManager > Block > Message > getLanguage > User.
            // See also T180050 and T226777.
            throw new LogicException( __METHOD__ . ' requires a loaded User object' );
        }
        if ( $response->headersSent() ) {
            throw new LogicException( __METHOD__ . ' must be called pre-send' );
        }
 
        $block = $user->getBlock();
        $isAnon = $user->isAnon();
 
        if ( $block ) {
            foreach ( $block->toArray() as $originalBlock ) {
                // TODO: Improve on simply tracking the first trackable block (T225654)
                if ( $originalBlock instanceof DatabaseBlock
                    && $this->shouldTrackBlockWithCookie( $originalBlock, $isAnon )
                ) {
                    $this->setBlockCookie( $originalBlock, $response );
                    return;
                }
            }
        }
    }
 
    private function setBlockCookie( DatabaseBlock $block, WebResponse $response ) {
        // Calculate the default expiry time.
        $maxExpiryTime = wfTimestamp( TS_MW, (int)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
        $expiryValue = (int)wfTimestamp( TS_UNIX, $expiryTime );
        $cookieOptions = [ 'httpOnly' => false ];
        $cookieValue = $this->getCookieValue( $block );
        $response->setCookie( 'BlockID', $cookieValue, $expiryValue, $cookieOptions );
    }
 
    private function shouldTrackBlockWithCookie( DatabaseBlock $block, $isAnon ) {
        switch ( $block->getType() ) {
            case DatabaseBlock::TYPE_IP:
            case DatabaseBlock::TYPE_RANGE:
                return $isAnon && $this->options->get( MainConfigNames::CookieSetOnIpBlock );
            case DatabaseBlock::TYPE_USER:
                return !$isAnon &&
                    $this->options->get( MainConfigNames::CookieSetOnAutoblock ) &&
                    $block->isAutoblocking();
            default:
                return false;
        }
    }
 
    public static function clearBlockCookie( WebResponse $response ) {
        $response->clearCookie( 'BlockID', [ 'httpOnly' => false ] );
    }
 
    private 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( MainConfigNames::SecretKey ) ) {
            // If there's no secret key, just use the ID as given.
            return (int)$id;
        }
        $storedHmac = substr( $cookieValue, $bangPos + 1 );
        $calculatedHmac = MWCryptHash::hmac( $id, $this->options->get( MainConfigNames::SecretKey ), false );
        if ( $calculatedHmac === $storedHmac ) {
            return (int)$id;
        } else {
            return null;
        }
    }
 
    private function getCookieValue( DatabaseBlock $block ) {
        $id = (string)$block->getId();
        if ( !$this->options->get( MainConfigNames::SecretKey ) ) {
            // If there's no secret key, don't append a HMAC.
            return $id;
        }
        $hmac = MWCryptHash::hmac( $id, $this->options->get( MainConfigNames::SecretKey ), false );
        return $id . '!' . $hmac;
    }
}