includes/ExternalLinks/LinkFilter.php
<?php
/**
* 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
*/
namespace MediaWiki\ExternalLinks;
use Content;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use StringUtils;
use TextContent;
use Wikimedia\IPUtils;
use Wikimedia\Rdbms\IExpression;
use Wikimedia\Rdbms\LikeMatch;
use Wikimedia\Rdbms\LikeValue;
use Wikimedia\Rdbms\OrExpressionGroup;
/**
* Utilities for formatting and querying the externallinks table.
*
* This is primarily used by \MediaWiki\Deferred\LinksUpdate\ExternalLinksTable
* for managing the storage layer, and by SpecialLinkSearch and ApiQueryExtLinksUsage
* as query interface.
*
* For spam removal and anti-spam meausures based on this, see also:
* - maintenance/cleanupSpam.php
* - SpamBlacklist extension
* - AbuseFilter extension (Special:BlockedExternalDomains, T337431)
*/
class LinkFilter {
/**
* Check whether $content contains a link to $filterEntry
*
* @param Content $content Content to check
* @param string $filterEntry Domainparts, see makeRegex() for more details
* @param string $protocol 'http://' or 'https://'
* @return int 0 if no match or 1 if there's at least one match
*/
public static function matchEntry( Content $content, $filterEntry, $protocol = 'http://' ) {
if ( !( $content instanceof TextContent ) ) {
// TODO: handle other types of content too.
// Maybe create ContentHandler::matchFilter( LinkFilter ).
// Think about a common base class for LinkFilter and MagicWord.
return 0;
}
$text = $content->getText();
$regex = self::makeRegex( $filterEntry, $protocol );
return preg_match( $regex, $text );
}
/**
* Build a regex pattern for $filterEntry.
*
* @todo This doesn't match the rest of the functionality here.
* @param string $filterEntry URL, if it begins with "*.", it'll be
* replaced to match any subdomain
* @param string $protocol 'http://' or 'https://'
* @return string Regex pattern, for preg_match()
*/
private static function makeRegex( $filterEntry, $protocol ) {
$regex = '!' . preg_quote( $protocol, '!' );
if ( substr( $filterEntry, 0, 2 ) == '*.' ) {
$regex .= '(?:[A-Za-z0-9.-]+\.|)';
$filterEntry = substr( $filterEntry, 2 );
}
$regex .= preg_quote( $filterEntry, '!' ) . '!Si';
return $regex;
}
/**
* Canonicalize a hostname for the externallinks table
*
* @param string $host
* @param bool $reverse whether to reverse the domain name or not
* @return string
*/
private static function indexifyHost( $host, $reverse = true ) {
// Canonicalize.
$host = rawurldecode( $host );
if ( $host !== '' ) {
$tmp = idn_to_utf8( $host );
if ( $tmp !== false ) {
$host = $tmp;
}
}
$okChars = 'a-zA-Z0-9\\-._~!$&\'()*+,;=';
if ( StringUtils::isUtf8( $host ) ) {
// Save a little space by not percent-encoding valid UTF-8 bytes
$okChars .= '\x80-\xf4';
}
$host = preg_replace_callback(
'<[^' . $okChars . ']+>',
static fn ( $m ) => rawurlencode( $m[0] ),
strtolower( $host )
);
// IPv6? RFC 3986 syntax.
if ( preg_match( '/^\[([0-9a-f:*]+)\]$/', rawurldecode( $host ), $m ) ) {
$ip = $m[1];
if ( IPUtils::isValid( $ip ) ) {
if ( !$reverse ) {
return '[' . IPUtils::sanitizeIP( $ip ) . ']';
}
return 'V6.' . implode( '.', explode( ':', IPUtils::sanitizeIP( $ip ) ) ) . '.';
}
if ( substr( $ip, -2 ) === ':*' ) {
$cutIp = substr( $ip, 0, -2 );
if ( IPUtils::isValid( "{$cutIp}::" ) ) {
// Wildcard IP doesn't contain "::", so multiple parts can be wild
$ct = count( explode( ':', $ip ) ) - 1;
if ( !$reverse ) {
return '[' . IPUtils::sanitizeIP( "{$cutIp}::" ) . ']';
}
return 'V6.' .
implode( '.', array_slice( explode( ':', IPUtils::sanitizeIP( "{$cutIp}::" ) ), 0, $ct ) ) .
'.*.';
}
if ( IPUtils::isValid( "{$cutIp}:1" ) ) {
// Wildcard IP does contain "::", so only the last part is wild
if ( !$reverse ) {
return '[' . IPUtils::sanitizeIP( "{$cutIp}:1" ) . ']';
}
return 'V6.' .
substr( implode( '.', explode( ':', IPUtils::sanitizeIP( "{$cutIp}:1" ) ) ), 0, -1 ) .
'*.';
}
}
}
// Regularize explicit specification of the DNS root.
// Browsers seem to do this for IPv4 literals too.
if ( substr( $host, -1 ) === '.' ) {
$host = substr( $host, 0, -1 );
}
// IPv4?
$b = '(?:0*25[0-5]|0*2[0-4][0-9]|0*1[0-9][0-9]|0*[0-9]?[0-9])';
if ( preg_match( "/^(?:{$b}\.){3}{$b}$|^(?:{$b}\.){1,3}\*$/", $host ) ) {
if ( !$reverse ) {
return $host;
}
return 'V4.' . implode( '.', array_map( static function ( $v ) {
return $v === '*' ? $v : (int)$v;
}, explode( '.', $host ) ) ) . '.';
}
// Must be a host name.
if ( $reverse ) {
return implode( '.', array_reverse( explode( '.', $host ) ) ) . '.';
} else {
return $host;
}
}
/**
* Convert given URL to format for the externallinks table
*
* @since 1.33
* @param string $url
* @param bool $reverseDomain
* @return string[][] One entry. Empty array on error.
* Each entry is an array in form of <host,path>
*/
public static function makeIndexes( $url, $reverseDomain = true ) {
// NOTE: refreshExternallinksIndex.php assumes that only protocol-relative URLs return more
// than one index, and that the indexes for protocol-relative URLs only vary in the "http://"
// versus "https://" prefix. If you change that, you'll likely need to update
// refreshExternallinksIndex.php accordingly.
$bits = MediaWikiServices::getInstance()->getUrlUtils()->parse( $url );
if ( !$bits ) {
return [];
}
// URI RFC identifies the email/server part of mailto or news protocol as 'path',
// while we want to match the email's domain or news server the same way we are
// matching hosts for other URLs.
if ( in_array( $bits['scheme'], [ 'mailto', 'news' ] ) ) {
// (T347574) Only set host if it's not already set (if // is used)
if ( array_key_exists( 'path', $bits ) ) {
$bits['host'] = $bits['path'];
}
$bits['path'] = '';
}
// Reverse the labels in the hostname, convert to lower case, unless it's an IP.
// For emails turn it into "domain.reversed@localpart"
if ( $bits['scheme'] == 'mailto' ) {
$mailparts = explode( '@', $bits['host'], 2 );
if ( count( $mailparts ) === 2 ) {
$domainpart = self::indexifyHost( $mailparts[1], $reverseDomain );
} else {
// No @, assume it's a local part with no domain
$domainpart = '';
}
if ( $reverseDomain ) {
$bits['host'] = $domainpart . '@' . $mailparts[0];
} else {
$bits['host'] = $mailparts[0] . '@' . $domainpart;
}
} else {
$bits['host'] = self::indexifyHost( $bits['host'], $reverseDomain );
}
// Reconstruct the pseudo-URL
$index = $bits['scheme'] . $bits['delimiter'] . $bits['host'];
// Leave out user and password. Add the port, path, query and fragment
if ( isset( $bits['port'] ) ) {
$index .= ':' . $bits['port'];
}
$index2 = $bits['path'] ?? '/';
if ( isset( $bits['query'] ) ) {
$index2 .= '?' . $bits['query'];
}
if ( isset( $bits['fragment'] ) ) {
$index2 .= '#' . $bits['fragment'];
}
if ( $bits['scheme'] == '' ) {
return [ [ "https:$index", $index2 ] ];
} else {
return [ [ $index, $index2 ] ];
}
}
/**
* Converts a set of URLs to be able to compare them with existing indexes
* @since 1.41
* @param string[] $urls List of URLs to be indexed
* @return string[]
*/
public static function getIndexedUrlsNonReversed( $urls ) {
$newLinks = [];
foreach ( $urls as $url ) {
$indexes = self::makeIndexes( $url, false );
if ( !$indexes ) {
continue;
}
foreach ( $indexes as $index ) {
$newLinks[] = $index[0] . $index[1];
}
}
return $newLinks;
}
public static function reverseIndexes( $domainIndex ) {
$bits = MediaWikiServices::getInstance()->getUrlUtils()->parse( $domainIndex );
if ( !$bits ) {
return '';
}
// Reverse the labels in the hostname, convert to lower case, unless it's an IP.
// For emails turn it into "domain.reversed@localpart"
if ( $bits['scheme'] == 'mailto' ) {
$mailparts = explode( '@', $bits['path'], 2 );
if ( count( $mailparts ) === 2 ) {
$domainpart = rtrim( self::reverseDomain( $mailparts[0] ), '.' );
} else {
// No @, assume it's a local part with no domain
$domainpart = '';
}
$bits['host'] = $mailparts[1] . '@' . $domainpart;
} else {
$bits['host'] = rtrim( self::reverseDomain( $bits['host'] ), '.' );
}
$index = $bits['scheme'] . $bits['delimiter'] . $bits['host'];
if ( isset( $bits['port'] ) && $bits['port'] ) {
$index .= ':' . $bits['port'];
}
return $index;
}
private static function reverseDomain( $domain ) {
if ( substr( $domain, 0, 3 ) === 'V6.' ) {
$ipv6 = str_replace( '.', ':', trim( substr( $domain, 3 ), '.' ) );
if ( IPUtils::isValid( $ipv6 ) ) {
return '[' . $ipv6 . ']';
}
} elseif ( substr( $domain, 0, 3 ) === 'V4.' ) {
$ipv4 = trim( substr( $domain, 3 ), '.' );
if ( IPUtils::isValid( $ipv4 ) ) {
return $ipv4;
}
}
return self::indexifyHost( $domain );
}
/**
* Return conditions for the externallinks table from a given filter entry.
*
* There are several ways you can query:
*
* *.domain.com - Matches domain.com and www.domain.com
* domain.com - Matches domain.com or domain.com/ but not www.domain.com
* *.domain.com/x - Matches domain.com/xy or www.domain.com/xy. Also probably matches
* domain.com/foobar/xy due to limitations of LIKE syntax.
* domain.com/x - Matches domain.com/xy but not www.domain.com/xy
* 192.0.2.* - Matches any IP in 192.0.2.0/24. Can also have a path appended.
* [2001:db8::*] - Matches any IP in 2001:db8::/112. Can also have a path appended.
* [2001:db8:*] - Matches any IP in 2001:db8::/32. Can also have a path appended.
* foo@domain.com - With protocol 'mailto:', matches the email address foo@domain.com.
* *@domain.com - With protocol 'mailto:', matches any email address at domain.com, but
* not subdomains like foo@mail.domain.com
*
* Asterisks in any other location are considered invalid.
*
* @since 1.33
* @param string $filterEntry Filter entry, as described above
* @param array $options Options are:
* - protocol: (null, string, array) Protocol to query (default: `http://` and `https://`)
* - oneWildcard: (bool) Stop at the first wildcard (default: false)
* - db: (IReadableDatabase|null) Database for building SQL text.
* @return array|false Query conditions (to be ANDed) or false on error.
*/
public static function getQueryConditions( $filterEntry, array $options = [] ) {
$options += [
'protocol' => [ 'http://', 'https://' ],
'oneWildcard' => false,
'db' => null,
];
$domainGaps = MediaWikiServices::getInstance()->getMainConfig()->get(
MainConfigNames::ExternalLinksDomainGaps
);
if ( is_string( $options['protocol'] ) ) {
$options['protocol'] = [ $options['protocol'] ];
} elseif ( $options['protocol'] === null ) {
$options['protocol'] = [ 'http://', 'https://' ];
}
$domainConditions = [];
$db = $options['db'] ?: MediaWikiServices::getInstance()->getConnectionProvider()->getReplicaDatabase();
foreach ( $options['protocol'] as $protocol ) {
$like = self::makeLikeArray( $filterEntry, $protocol );
if ( $like === false ) {
continue;
}
[ $likeDomain, $likePath ] = $like;
$trimmedlikeDomain = self::keepOneWildcard( $likeDomain );
if ( $trimmedlikeDomain[count( $trimmedlikeDomain ) - 1] instanceof LikeMatch ) {
array_pop( $trimmedlikeDomain );
}
$index1 = implode( '', $trimmedlikeDomain );
if ( $options['oneWildcard'] && $likePath[0] != '/' ) {
$thisDomainExpr = $db->expr( 'el_to_domain_index', '=', $index1 );
} else {
$thisDomainExpr = $db->expr(
'el_to_domain_index',
IExpression::LIKE,
new LikeValue( $index1, $db->anyString() )
);
}
foreach ( $domainGaps[$index1] ?? [] as $from => $to ) {
$thisDomainExpr = $thisDomainExpr->andExpr( $db->expr( 'el_id', '<', $from )->or( 'el_id', '>', $to ) );
}
$domainConditions[] = $thisDomainExpr;
}
if ( !$domainConditions ) {
return false;
}
// @phan-suppress-next-line PhanPossiblyUndeclaredVariable
$trimmedlikePath = self::keepOneWildcard( $likePath );
if ( $trimmedlikePath[count( $trimmedlikePath ) - 1] instanceof LikeMatch ) {
array_pop( $trimmedlikePath );
}
$index2 = implode( '', $trimmedlikePath );
return [
new OrExpressionGroup( ...$domainConditions ),
$db->expr( 'el_to_path', IExpression::LIKE, new LikeValue( $index2, $db->anyString() ) ),
];
}
public static function getProtocolPrefix( $protocol ) {
// Find the right prefix
$urlProtocols = MediaWikiServices::getInstance()->getMainConfig()
->get( MainConfigNames::UrlProtocols );
if ( $protocol && !in_array( $protocol, $urlProtocols ) ) {
foreach ( $urlProtocols as $p ) {
if ( str_starts_with( $p, $protocol ) ) {
$protocol = $p;
break;
}
}
return $protocol;
} else {
return null;
}
}
public static function prepareProtocols() {
$urlProtocols = MediaWikiServices::getInstance()->getMainConfig()
->get( MainConfigNames::UrlProtocols );
$protocols = [ '' ];
foreach ( $urlProtocols as $p ) {
if ( $p !== '//' ) {
$protocols[] = substr( $p, 0, strpos( $p, ':' ) );
}
}
return $protocols;
}
/**
* Make an array to be used for calls to Database::buildLike(), which
* will match the specified string.
*
* This function does the same as LinkFilter::makeIndexes(), except it also takes care
* of adding wildcards
*
* @note You probably want self::getQueryConditions() instead
* @param string $filterEntry Filter entry, @see self::getQueryConditions()
* @param string $protocol Protocol (default http://)
* @return array|false Array to be passed to Database::buildLike() or false on error
*/
public static function makeLikeArray( $filterEntry, $protocol = 'http://' ) {
$services = MediaWikiServices::getInstance();
$db = $services->getConnectionProvider()->getReplicaDatabase();
$likeDomain = [];
$likePath = [];
$target = $protocol . $filterEntry;
$bits = $services->getUrlUtils()->parse( $target );
if ( !$bits ) {
return false;
}
// URI RFC identifies the email/server part of mailto or news protocol as 'path',
// while we want to match the email's domain or news server the same way we are
// matching hosts for other URLs.
if ( in_array( $bits['scheme'], [ 'mailto', 'news' ] ) ) {
$bits['host'] = $bits['path'];
$bits['path'] = '';
}
$subdomains = false;
if ( $bits['scheme'] === 'mailto' && strpos( $bits['host'], '@' ) ) {
// Email address with domain and non-empty local part
$mailparts = explode( '@', $bits['host'], 2 );
$domainpart = self::indexifyHost( $mailparts[1] );
if ( $mailparts[0] === '*' ) {
$subdomains = true;
$bits['host'] = $domainpart . '@';
} else {
$bits['host'] = $domainpart . '@' . $mailparts[0];
}
} else {
// Non-email, or email with only a domain part.
$bits['host'] = self::indexifyHost( $bits['host'] );
if ( substr( $bits['host'], -3 ) === '.*.' ) {
$subdomains = true;
$bits['host'] = substr( $bits['host'], 0, -2 );
}
}
$likeDomain[] = $bits['scheme'] . $bits['delimiter'] . $bits['host'];
if ( $subdomains ) {
$likeDomain[] = $db->anyString();
}
if ( isset( $bits['port'] ) ) {
$likeDomain[] = ':' . $bits['port'];
}
if ( isset( $bits['path'] ) ) {
$likePath[] = $bits['path'];
} else {
$likePath[] = '/';
}
if ( isset( $bits['query'] ) ) {
$likePath[] = '?' . $bits['query'];
}
if ( isset( $bits['fragment'] ) ) {
$likePath[] = '#' . $bits['fragment'];
}
$likePath[] = $db->anyString();
// Check for stray asterisks: asterisk only allowed at the start of the domain
foreach ( array_merge( $likeDomain, $likePath ) as $likepart ) {
if ( !( $likepart instanceof LikeMatch ) && strpos( $likepart, '*' ) !== false ) {
return false;
}
}
return [ $likeDomain, $likePath ];
}
/**
* Filters an array returned by makeLikeArray(), removing everything past first
* pattern placeholder.
*
* @note You probably want self::getQueryConditions() instead
* @param array $arr Array to filter
* @return array Filtered array
*/
public static function keepOneWildcard( $arr ) {
if ( !is_array( $arr ) ) {
return $arr;
}
foreach ( $arr as $key => $value ) {
if ( $value instanceof LikeMatch ) {
return array_slice( $arr, 0, $key + 1 );
}
}
return $arr;
}
}
/** @deprecated class alias since 1.40 */
class_alias( LinkFilter::class, 'LinkFilter' );