mediawiki-extensions-Confir.../ConfirmEdit.php

799 lines
23 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) 2005-2007 Brion Vibber <brion@wikimedia.org>
* 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
*
* @addtogroup Extensions
*/
if ( defined( 'MEDIAWIKI' ) ) {
global $wgExtensionFunctions, $wgGroupPermissions;
$wgExtensionFunctions[] = 'ceSetup';
$wgExtensionCredits['other'][] = array(
'name' => 'ConfirmEdit',
'author' => 'Brion Vibber',
'url' => 'http://www.mediawiki.org/wiki/Extension:ConfirmEdit',
'description' => 'Simple captcha implementation',
);
# 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
$wgGroupPermissions['sysop' ]['skipcaptcha'] = true;
/**
* List of IP ranges to allow to skip the captcha, similar to the group setting:
* "$wgGroupPermission[...]['skipcaptcha'] = true"
*
* Specific IP addresses or CIDR-style ranges may be used,
* for instance:
* $wgCaptchaWhitelistIP = array('192.168.1.0/24', '10.1.0.0/16');
*/
$wgCaptchaWhitelistIP = false;
global $wgCaptcha, $wgCaptchaClass, $wgCaptchaTriggers;
$wgCaptcha = null;
$wgCaptchaClass = 'SimpleCaptcha';
/**
* Actions which can trigger a captcha
*
* 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.
*
* The captcha code should not use $wgCaptchaTriggers, but CaptchaTriggers()
* which also takes into account per namespace triggering.
*/
$wgCaptchaTriggers = array();
$wgCaptchaTriggers['edit'] = false; // Would check on every edit
$wgCaptchaTriggers['create'] = false; // Check on page creation.
$wgCaptchaTriggers['addurl'] = true; // Check on edits that add URLs
$wgCaptchaTriggers['createaccount'] = true; // Special:Userlogin&type=signup
$wgCaptchaTriggers['badlogin'] = true; // Special:Userlogin after failure
/**
* You may wish to apply special rules for captcha triggering on some namespaces.
* $wgCaptchaTriggersOnNamespace[<namespace id>][<trigger>] forces an always on /
* always off configuration with that trigger for the given namespace.
* Leave unset to use the global options ($wgCaptchaTriggers).
*
* Shall not be used with 'createaccount' (it is not checked).
*/
$wgCaptchaTriggersOnNamespace = array();
#Example:
#$wgCaptchaTriggersOnNamespace[NS_TALK]['create'] = false; //Allow creation of talk pages without captchas.
#$wgCaptchaTriggersOnNamespace[NS_PROJECT]['edit'] = true; //Show captcha whenever editing Project pages.
/**
* Indicate how to store per-session data required to match up the
* internal captcha data with the editor.
*
* 'CaptchaSessionStore' uses PHP's session storage, which is cookie-based
* and may fail for anons with cookies disabled.
*
* 'CaptchaCacheStore' uses $wgMemc, which avoids the cookie dependency
* but may be fragile depending on cache configuration.
*/
global $wgCaptchaStorageClass;
$wgCaptchaStorageClass = 'CaptchaSessionStore';
/**
* Number of seconds a captcha session should last in the data cache
* before expiring when managing through CaptchaCacheStore class.
*
* Default is a half hour.
*/
global $wgCaptchaSessionExpiration;
$wgCaptchaSessionExpiration = 30 * 60;
/**
* Number of seconds after a bad login that a captcha will be shown to
* that client on the login form to slow down password-guessing bots.
*
* Has no effect if 'badlogin' is disabled in $wgCaptchaTriggers or
* if there is not a caching engine enabled.
*
* Default is five minutes.
*/
global $wgCaptchaBadLoginExpiration;
$wgCaptchaBadLoginExpiration = 5 * 60;
/**
* 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';
* Local admins can define a whitelist under [[MediaWiki:captcha-addurl-whitelist]]
*/
$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 $lang => $messages )
$wgMessageCache->addMessages( $messages, $lang );
global $wgHooks, $wgCaptcha, $wgCaptchaClass, $wgSpecialPages;
$wgCaptcha = new $wgCaptchaClass();
$wgHooks['EditFilter'][] = array( &$wgCaptcha, 'confirmEdit' );
$wgHooks['UserCreateForm'][] = array( &$wgCaptcha, 'injectUserCreate' );
$wgHooks['AbortNewAccount'][] = array( &$wgCaptcha, 'confirmUserCreate' );
$wgHooks['LoginAuthenticateAudit'][] = array( &$wgCaptcha, 'triggerUserLogin' );
$wgHooks['UserLoginForm'][] = array( &$wgCaptcha, 'injectUserLogin' );
$wgHooks['AbortLogin'][] = array( &$wgCaptcha, 'confirmUserLogin' );
global $wgGroupPermissions, $wgCaptchaTriggers;
if( !$wgGroupPermissions['*']['read'] && $wgCaptchaTriggers['badlogin'] ) {
// We need to ensure that the captcha interface is accessible
// so that unauthenticated users can actually get in after a
// mistaken password typing.
global $wgWhitelistRead;
$image = Title::makeTitle( NS_SPECIAL, 'Captcha/image' );
$help = Title::makeTitle( NS_SPECIAL, 'Captcha/help' );
$wgWhitelistRead[] = $image->getPrefixedText();
$wgWhitelistRead[] = $help->getPrefixedText();
}
}
/**
* 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 {
function SimpleCaptcha() {
global $wgCaptchaStorageClass;
$this->storage = new $wgCaptchaStorageClass;
}
/**
* 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( $this->getMessage( $this->action ) );
$out->addHTML( $this->getForm() );
}
/**
* Show a message asking the user to enter a captcha on edit
* The result will be treated as wiki text
*
* @param $action Action being performed
* @return string
*/
function getMessage( $action ) {
$name = 'captcha-' . $action;
$text = wfMsg( $name );
# Obtain a more tailored message, if possible, otherwise, fall back to
# the default for edits
return wfEmptyMsg( $name, $text ) ? wfMsg( 'captcha-edit' ) : $text;
}
/**
* 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( $this->getMessage( 'createaccount' ) ) .
$this->getForm() .
"</div>\n" );
}
return true;
}
/**
* Inject a captcha into the user login form after a failed
* password attempt as a speedbump for mass attacks.
* @fixme if multiple thingies insert a header, could break
* @param SimpleTemplate $template
* @return bool true to keep running callbacks
*/
function injectUserLogin( &$template ) {
if( $this->isBadLoginTriggered() ) {
global $wgOut;
$template->set( 'header',
"<div class='captcha'>" .
$wgOut->parse( $this->getMessage( 'badlogin' ) ) .
$this->getForm() .
"</div>\n" );
}
return true;
}
/**
* When a bad login attempt is made, increment an expiring counter
* in the memcache cloud. Later checks for this may trigger a
* captcha display to prevent too many hits from the same place.
* @param User $user
* @param string $password
* @param int $retval authentication return value
* @return bool true to keep running callbacks
*/
function triggerUserLogin( $user, $password, $retval ) {
global $wgCaptchaTriggers, $wgCaptchaBadLoginExpiration, $wgMemc;
if( $retval == LoginForm::WRONG_PASS && $wgCaptchaTriggers['badlogin'] ) {
$key = $this->badLoginKey();
$count = $wgMemc->get( $key );
if( !$count ) {
$wgMemc->add( $key, 0, $wgCaptchaBadLoginExpiration );
}
$count = $wgMemc->incr( $key );
}
return true;
}
/**
* Check if a bad login has already been registered for this
* IP address. If so, require a captcha.
* @return bool
* @access private
*/
function isBadLoginTriggered() {
global $wgMemc;
return intval( $wgMemc->get( $this->badLoginKey() ) ) > 0;
}
/**
* Internal cache key for badlogin checks.
* @return string
* @access private
*/
function badLoginKey() {
return wfMemcKey( 'captcha', 'badlogin', 'ip', wfGetIP() );
}
/**
* 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 $action (edit/create/addurl...)
* @return bool true if action triggers captcha on editPage's namespace
*/
function captchaTriggers( &$editPage, $action) {
global $wgCaptchaTriggers, $wgCaptchaTriggersOnNamespace;
//Special config for this NS?
if (isset( $wgCaptchaTriggersOnNamespace[$editPage->mTitle->getNamespace()][$action] ) )
return $wgCaptchaTriggersOnNamespace[$editPage->mTitle->getNamespace()][$action];
return ( !empty( $wgCaptchaTriggers[$action] ) ); //Default
}
/**
* @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 $wgCaptchaWhitelistIP;
if( !empty( $wgCaptchaWhitelistIP ) ) {
$ip = wfGetIp();
foreach ( $wgCaptchaWhitelistIP as $range ) {
if ( IP::isInRange( $ip, $range ) ) {
return false;
}
}
}
global $wgEmailAuthentication, $ceAllowConfirmedEmail;
if( $wgEmailAuthentication && $ceAllowConfirmedEmail &&
$wgUser->isEmailConfirmed() ) {
wfDebug( "ConfirmEdit: user has confirmed mail, skipping captcha\n" );
return false;
}
if( $this->captchaTriggers( $editPage, 'edit' ) ) {
// Check on all edits
global $wgUser, $wgTitle;
$this->trigger = sprintf( "edit trigger by '%s' at [[%s]]",
$wgUser->getName(),
$wgTitle->getPrefixedText() );
$this->action = 'edit';
wfDebug( "ConfirmEdit: checking all edits...\n" );
return true;
}
if( $this->captchaTriggers( $editPage, 'create' ) && !$editPage->mTitle->exists() ) {
//Check if creating a page
global $wgUser, $wgTitle;
$this->trigger = sprintf( "Create trigger by '%s' at [[%s]]",
$wgUser->getName(),
$wgTitle->getPrefixedText() );
$this->action = 'create';
wfDebug( "ConfirmEdit: checking on page creation...\n" );
return true;
}
if( $this->captchaTriggers( $editPage, '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 ) );
$this->action = 'addurl';
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 ) );
$this->action = 'edit';
return true;
}
}
}
}
return false;
}
/**
* Filter callback function for URL whitelisting
* @param string url to check
* @return bool true if unknown, false if whitelisted
* @access private
*/
function filterLink( $url ) {
global $wgCaptchaWhitelist;
$source = wfMsgForContent( 'captcha-addurl-whitelist' );
$whitelist = wfEmptyMsg( 'captcha-addurl-whitelist', $source )
? false
: $this->buildRegexes( explode( "\n", $source ) );
$cwl = $wgCaptchaWhitelist !== false ? preg_match( $wgCaptchaWhitelist, $url ) : false;
$wl = $whitelist !== false ? preg_match( $whitelist, $url ) : false;
return !( $cwl || $wl );
}
/**
* Build regex from whitelist
* @param string lines from [[MediaWiki:Captcha-addurl-whitelist]]
* @return string Regex or bool false if whitelist is empty
* @access private
*/
function buildRegexes( $lines ) {
# Code duplicated from the SpamBlacklist extension (r19197)
# Strip comments and whitespace, then remove blanks
$lines = array_filter( array_map( 'trim', preg_replace( '/#.*$/', '', $lines ) ) );
# No lines, don't make a regex which will match everything
if ( count( $lines ) == 0 ) {
wfDebug( "No lines\n" );
return false;
} else {
# Make regex
# It's faster using the S modifier even though it will usually only be run once
//$regex = 'http://+[a-z0-9_\-.]*(' . implode( '|', $lines ) . ')';
//return '/' . str_replace( '/', '\/', preg_replace('|\\\*/|', '/', $regex) ) . '/Si';
$regexes = '';
$regexStart = '/http:\/\/+[a-z0-9_\-.]*(';
$regexEnd = ')/Si';
$regexMax = 4096;
$build = false;
foreach( $lines as $line ) {
// FIXME: not very robust size check, but should work. :)
if( $build === false ) {
$build = $line;
} elseif( strlen( $build ) + strlen( $line ) > $regexMax ) {
$regexes .= $regexStart .
str_replace( '/', '\/', preg_replace('|\\\*/|', '/', $build) ) .
$regexEnd;
$build = $line;
} else {
$build .= '|' . $line;
}
}
if( $build !== false ) {
$regexes .= $regexStart .
str_replace( '/', '\/', preg_replace('|\\\*/|', '/', $build) ) .
$regexEnd;
}
return $regexes;
}
}
/**
* 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 need to show captcha.\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;
}
/**
* Hook for user login form submissions.
* @param User $u
* @param string $message
* @return bool true to continue, false to abort user creation
*/
function confirmUserLogin( $u, $pass, &$retval ) {
if( $this->isBadLoginTriggered() ) {
$this->trigger = "post-badlogin login '" . $u->getName() . "'";
if( !$this->passCaptcha() ) {
$message = wfMsg( 'captcha-badlogin-fail' );
// Emulate a bad-password return to confuse the shit out of attackers
$retval = LoginForm::WRONG_PASS;
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() );
}
$this->storage->store( $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' );
return $this->storage->retrieve( $index );
}
/**
* Clear out existing captcha info from the session, to ensure
* it can't be reused.
*/
function clearCaptcha( $info ) {
$this->storage->clear( $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' ) );
if ( $this->storage->cookiesNeeded() ) {
$wgOut->addWikiText( wfMsg( 'captchahelp-cookies-needed' ) );
}
}
}
class CaptchaSessionStore {
function store( $index, $info ) {
$_SESSION['captcha' . $info['index']] = $info;
}
function retrieve( $index ) {
if( isset( $_SESSION['captcha' . $index] ) ) {
return $_SESSION['captcha' . $index];
} else {
return false;
}
}
function clear( $index ) {
unset( $_SESSION['captcha' . $index] );
}
function cookiesNeeded() {
return true;
}
}
class CaptchaCacheStore {
function store( $index, $info ) {
global $wgMemc, $wgCaptchaSessionExpiration;
$wgMemc->set( wfMemcKey( 'captcha', $index ), $info,
$wgCaptchaSessionExpiration );
}
function retrieve( $index ) {
global $wgMemc;
$info = $wgMemc->get( wfMemcKey( 'captcha', $index ) );
if( $info ) {
return $info;
} else {
return false;
}
}
function clear( $index ) {
global $wgMemc;
$wgMemc->delete( wfMemcKey( 'captcha', $index ) );
}
function cookiesNeeded() {
return false;
}
}
} # End invocation guard