mediawiki-extensions-Confir.../ConfirmEdit.php
Brion Vibber 51adfd5b2e * (bug 4823) Use full parser to extract URLs in ConfirmEdit checks.
Should work on 1.6 or higher, tested on 1.8 and 1.9
* (bug 8268) Fix regression in ConfirmEdit on 1.8 and higher when
  no parser hook extensions are present, leaving $wgParser stubbed
2006-12-15 10:06:58 +00:00

472 lines
13 KiB
PHP

<?php
/**
* Experimental captcha plugin framework.
* Not intended as a real production captcha system; derived classes
* can extend the base to produce their fancy images in place of the
* text-based test output here.
*
* Copyright (C) 2005, 2006 Brion Vibber <brion@pobox.com>
* http://www.mediawiki.org/
*
* 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.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @package MediaWiki
* @subpackage Extensions
*/
if ( defined( 'MEDIAWIKI' ) ) {
global $wgExtensionFunctions, $wgGroupPermissions;
$wgExtensionFunctions[] = 'ceSetup';
# Internationalisation file
require_once( 'ConfirmEdit.i18n.php' );
/**
* The 'skipcaptcha' permission key can be given out to
* let known-good users perform triggering actions without
* having to go through the captcha.
*
* By default, sysops and registered bot accounts will be
* able to skip, while others have to go through it.
*/
$wgGroupPermissions['*' ]['skipcaptcha'] = false;
$wgGroupPermissions['user' ]['skipcaptcha'] = false;
$wgGroupPermissions['autoconfirmed']['skipcaptcha'] = false;
$wgGroupPermissions['bot' ]['skipcaptcha'] = true; // registered bots
$wgGroupPermissions['sysop' ]['skipcaptcha'] = true;
global $wgCaptcha, $wgCaptchaClass, $wgCaptchaTriggers;
$wgCaptcha = null;
$wgCaptchaClass = 'SimpleCaptcha';
/**
* Currently the captcha works only for page edits.
*
* If the 'edit' trigger is on, *every* edit will trigger the captcha.
* This may be useful for protecting against vandalbot attacks.
*
* If using the default 'addurl' trigger, the captcha will trigger on
* edits that include URLs that aren't in the current version of the page.
* This should catch automated linkspammers without annoying people when
* they make more typical edits.
*/
$wgCaptchaTriggers = array();
$wgCaptchaTriggers['edit'] = false; // Would check on every edit
$wgCaptchaTriggers['addurl'] = true; // Check on edits that add URLs
$wgCaptchaTriggers['createaccount'] = true; // Special:Userlogin&type=signup
/**
* Allow users who have confirmed their e-mail addresses to post
* URL links without being harassed by the captcha.
*/
global $ceAllowConfirmedEmail;
$ceAllowConfirmedEmail = false;
/**
* Regex to whitelist URLs to known-good sites...
* For instance:
* $wgCaptchaWhitelist = '#^https?://([a-z0-9-]+\\.)?(wikimedia|wikipedia)\.org/#i';
* @fixme Use the 'spam-whitelist' thingy instead?
*/
$wgCaptchaWhitelist = false;
/**
* Additional regexes to check for. Use full regexes; can match things
* other than URLs such as junk edits.
*
* If the new version matches one and the old version doesn't,
* toss up the captcha screen.
*
* @fixme Add a message for local admins to add items as well.
*/
$wgCaptchaRegexes = array();
/** Register special page */
global $wgSpecialPages;
$wgSpecialPages['Captcha'] = array( /*class*/ 'SpecialPage', /*name*/'Captcha', /*restriction*/ '',
/*listed*/ false, /*function*/ false, /*file*/ false );
/**
* Set up message strings for captcha utilities.
*/
function ceSetup() {
# Add messages
global $wgMessageCache, $wgConfirmEditMessages;
foreach( $wgConfirmEditMessages as $key => $value ) {
$wgMessageCache->addMessages( $wgConfirmEditMessages[$key], $key );
}
global $wgHooks, $wgCaptcha, $wgCaptchaClass, $wgSpecialPages;
$wgCaptcha = new $wgCaptchaClass();
$wgHooks['EditFilter'][] = array( &$wgCaptcha, 'confirmEdit' );
$wgHooks['UserCreateForm'][] = array( &$wgCaptcha, 'injectUserCreate' );
$wgHooks['AbortNewAccount'][] = array( &$wgCaptcha, 'confirmUserCreate' );
}
/**
* Entry point for Special:Captcha
*/
function wfSpecialCaptcha( $par = null ) {
global $wgCaptcha;
switch( $par ) {
case "image":
return $wgCaptcha->showImage();
case "help":
default:
return $wgCaptcha->showHelp();
}
}
class SimpleCaptcha {
/**
* Insert a captcha prompt into the edit form.
* This sample implementation generates a simple arithmetic operation;
* it would be easy to defeat by machine.
*
* Override this!
*
* @return string HTML
*/
function getForm() {
$a = mt_rand(0, 100);
$b = mt_rand(0, 10);
$op = mt_rand(0, 1) ? '+' : '-';
$test = "$a $op $b";
$answer = ($op == '+') ? ($a + $b) : ($a - $b);
$index = $this->storeCaptcha( array( 'answer' => $answer ) );
return "<p><label for=\"wpCaptchaWord\">$test</label> = " .
wfElement( 'input', array(
'name' => 'wpCaptchaWord',
'id' => 'wpCaptchaWord',
'tabindex' => 1 ) ) . // tab in before the edit textarea
"</p>\n" .
wfElement( 'input', array(
'type' => 'hidden',
'name' => 'wpCaptchaId',
'id' => 'wpCaptchaId',
'value' => $index ) );
}
/**
* Insert the captcha prompt into an edit form.
* @param OutputPage $out
*/
function editCallback( &$out ) {
$out->addWikiText( wfMsg( "captcha-short" ) );
$out->addHTML( $this->getForm() );
}
/**
* Inject whazawhoo
* @fixme if multiple thingies insert a header, could break
* @param SimpleTemplate $template
* @return bool true to keep running callbacks
*/
function injectUserCreate( &$template ) {
global $wgCaptchaTriggers, $wgOut;
if( $wgCaptchaTriggers['createaccount'] ) {
$template->set( 'header',
"<div class='captcha'>" .
$wgOut->parse( wfMsg( 'captcha-createaccount' ) ) .
$this->getForm() .
"</div>\n" );
}
return true;
}
/**
* Check if the submitted form matches the captcha session data provided
* by the plugin when the form was generated.
*
* Override this!
*
* @param WebRequest $request
* @param array $info
* @return bool
*/
function keyMatch( $request, $info ) {
return $request->getVal( 'wpCaptchaWord' ) == $info['answer'];
}
// ----------------------------------
/**
* @param EditPage $editPage
* @param string $newtext
* @param string $section
* @return bool true if the captcha should run
*/
function shouldCheck( &$editPage, $newtext, $section ) {
$this->trigger = '';
global $wgUser;
if( $wgUser->isAllowed( 'skipcaptcha' ) ) {
wfDebug( "ConfirmEdit: user group allows skipping captcha\n" );
return false;
}
global $wgEmailAuthentication, $ceAllowConfirmedEmail;
if( $wgEmailAuthentication && $ceAllowConfirmedEmail &&
$wgUser->isEmailConfirmed() ) {
wfDebug( "ConfirmEdit: user has confirmed mail, skipping captcha\n" );
return false;
}
global $wgCaptchaTriggers;
if( !empty( $wgCaptchaTriggers['edit'] ) ) {
// Check on all edits
global $wgUser, $wgTitle;
$this->trigger = sprintf( "edit trigger by '%s' at [[%s]]",
$wgUser->getName(),
$wgTitle->getPrefixedText() );
wfDebug( "ConfirmEdit: checking all edits...\n" );
return true;
}
if( !empty( $wgCaptchaTriggers['addurl'] ) ) {
// Only check edits that add URLs
$oldtext = $this->loadText( $editPage, $section );
$oldLinks = $this->findLinks( $oldtext );
$newLinks = $this->findLinks( $newtext );
$unknownLinks = array_filter( $newLinks, array( &$this, 'filterLink' ) );
$addedLinks = array_diff( $unknownLinks, $oldLinks );
$numLinks = count( $addedLinks );
if( $numLinks > 0 ) {
global $wgUser, $wgTitle;
$this->trigger = sprintf( "%dx url trigger by '%s' at [[%s]]: %s",
$numLinks,
$wgUser->getName(),
$wgTitle->getPrefixedText(),
implode( ", ", $addedLinks ) );
return true;
}
}
global $wgCaptchaRegexes;
if( !empty( $wgCaptchaRegexes ) ) {
// Custom regex checks
$oldtext = $this->loadText( $editPage, $section );
foreach( $wgCaptchaRegexes as $regex ) {
$newMatches = array();
if( preg_match_all( $regex, $newtext, $newMatches ) ) {
$oldMatches = array();
preg_match_all( $regex, $oldtext, $oldMatches );
$addedMatches = array_diff( $newMatches[0], $oldMatches[0] );
$numHits = count( $addedMatches );
if( $numHits > 0 ) {
global $wgUser, $wgTitle;
$this->trigger = sprintf( "%dx %s at [[%s]]: %s",
$numHits,
$regex,
$wgUser->getName(),
$wgTitle->getPrefixedText(),
implode( ", ", $addedMatches ) );
return true;
}
}
}
}
return false;
}
/**
* Filter callback function for URL whitelisting
* @return bool true if unknown, false if whitelisted
* @access private
*/
function filterLink( $url ) {
global $wgCaptchaWhitelist;
return !( $wgCaptchaWhitelist && preg_match( $wgCaptchaWhitelist, $url ) );
}
/**
* The main callback run on edit attempts.
* @param EditPage $editPage
* @param string $newtext
* @param string $section
* @param bool true to continue saving, false to abort and show a captcha form
*/
function confirmEdit( &$editPage, $newtext, $section ) {
if( $this->shouldCheck( $editPage, $newtext, $section ) ) {
if( $this->passCaptcha() ) {
return true;
} else {
$editPage->showEditForm( array( &$this, 'editCallback' ) );
return false;
}
} else {
wfDebug( "ConfirmEdit: no new links.\n" );
return true;
}
}
/**
* Hook for user creation form submissions.
* @param User $u
* @param string $message
* @return bool true to continue, false to abort user creation
*/
function confirmUserCreate( $u, &$message ) {
global $wgCaptchaTriggers;
if( $wgCaptchaTriggers['createaccount'] ) {
$this->trigger = "new account '" . $u->getName() . "'";
if( !$this->passCaptcha() ) {
$message = wfMsg( 'captcha-createaccount-fail' );
return false;
}
}
return true;
}
/**
* Given a required captcha run, test form input for correct
* input on the open session.
* @return bool if passed, false if failed or new session
*/
function passCaptcha() {
$info = $this->retrieveCaptcha();
if( $info ) {
global $wgRequest;
if( $this->keyMatch( $wgRequest, $info ) ) {
$this->log( "passed" );
$this->clearCaptcha( $info );
return true;
} else {
$this->clearCaptcha( $info );
$this->log( "bad form input" );
return false;
}
} else {
$this->log( "new captcha session" );
return false;
}
}
/**
* Log the status and any triggering info for debugging or statistics
* @param string $message
*/
function log( $message ) {
wfDebugLog( 'captcha', 'ConfirmEdit: ' . $message . '; ' . $this->trigger );
}
/**
* Generate a captcha session ID and save the info in PHP's session storage.
* (Requires the user to have cookies enabled to get through the captcha.)
*
* A random ID is used so legit users can make edits in multiple tabs or
* windows without being unnecessarily hobbled by a serial order requirement.
* Pass the returned id value into the edit form as wpCaptchaId.
*
* @param array $info data to store
* @return string captcha ID key
*/
function storeCaptcha( $info ) {
if( !isset( $info['index'] ) ) {
// Assign random index if we're not udpating
$info['index'] = strval( mt_rand() );
}
$_SESSION['captcha' . $info['index']] = $info;
return $info['index'];
}
/**
* Fetch this session's captcha info.
* @return mixed array of info, or false if missing
*/
function retrieveCaptcha() {
global $wgRequest;
$index = $wgRequest->getVal( 'wpCaptchaId' );
if( isset( $_SESSION['captcha' . $index] ) ) {
return $_SESSION['captcha' . $index];
} else {
return false;
}
}
/**
* Clear out existing captcha info from the session, to ensure
* it can't be reused.
*/
function clearCaptcha( $info ) {
unset( $_SESSION['captcha' . $info['index']] );
}
/**
* Retrieve the current version of the page or section being edited...
* @param EditPage $editPage
* @param string $section
* @return string
* @access private
*/
function loadText( $editPage, $section ) {
$rev = Revision::newFromTitle( $editPage->mTitle );
if( is_null( $rev ) ) {
return "";
} else {
$text = $rev->getText();
if( $section != '' ) {
return Article::getSection( $text, $section );
} else {
return $text;
}
}
}
/**
* Extract a list of all recognized HTTP links in the text.
* @param string $text
* @return array of strings
*/
function findLinks( $text ) {
global $wgParser, $wgTitle, $wgUser;
$options = new ParserOptions();
$text = $wgParser->preSaveTransform( $text, $wgTitle, $wgUser, $options );
$out = $wgParser->parse( $text, $wgTitle, $options );
return array_keys( $out->getExternalLinks() );
}
/**
* Show a page explaining what this wacky thing is.
*/
function showHelp() {
global $wgOut, $ceAllowConfirmedEmail;
$wgOut->setPageTitle( wfMsg( 'captchahelp-title' ) );
$wgOut->addWikiText( wfMsg( 'captchahelp-text' ) );
}
}
} # End invocation guard
?>