FancyCaptcha.class.php

   1 <?php
   2
   3 class FancyCaptcha extends SimpleCaptcha {
   4         /**
   5          * Check if the submitted form matches the captcha session data provided
   6          * by the plugin when the form was generated.
   7          *
   8          * @param string $answer
   9          * @param array $info
  10          * @return bool
  11          */
  12         function keyMatch( $answer, $info ) {
  13                 global $wgCaptchaSecret;
  14
  15                 $digest = $wgCaptchaSecret . $info['salt'] . $answer . $wgCaptchaSecret . $info['salt'];
  16                 $answerHash = substr( md5( $digest ), 0, 16 );
  17
  18                 if ( $answerHash == $info['hash'] ) {
  19                         wfDebug( "FancyCaptcha: answer hash matches expected {$info['hash']}\n" );
  20                         return true;
  21                 } else {
  22                         wfDebug( "FancyCaptcha: answer hashes to $answerHash, expected {$info['hash']}\n" );
  23                         return false;
  24                 }
  25         }
  26
  27         function addCaptchaAPI( &$resultArr ) {
  28                 $info = $this->pickImage();
  29                 if ( !$info ) {
  30                         $resultArr['captcha']['error'] = 'Out of images';
  31                         return;
  32                 }
  33                 $index = $this->storeCaptcha( $info );
  34                 $title = SpecialPage::getTitleFor( 'Captcha', 'image' );
  35                 $resultArr['captcha']['type'] = 'image';
  36                 $resultArr['captcha']['mime'] = 'image/png';
  37                 $resultArr['captcha']['id'] = $index;
  38                 $resultArr['captcha']['url'] = $title->getLocalUrl( 'wpCaptchaId=' . urlencode( $index ) );
  39         }
  40
  41         /**
  42          * Insert the captcha prompt into the edit form.
  43          */
  44         function getForm() {
  45                 $info = $this->pickImage();
  46                 if ( !$info ) {
  47                         throw new MWException( "Ran out of captcha images" );
  48                 }
  49
  50                 // Generate a random key for use of this captcha image in this session.
  51                 // This is needed so multiple edits in separate tabs or windows can
  52                 // go through without extra pain.
  53                 $index = $this->storeCaptcha( $info );
  54
  55                 wfDebug( "Captcha id $index using hash ${info['hash']}, salt ${info['salt']}.\n" );
  56
  57                 $title = SpecialPage::getTitleFor( 'Captcha', 'image' );
  58
  59                 return "<p>" .
  60                         Xml::element( 'img', array(
  61                                 'src'    => $title->getLocalUrl( 'wpCaptchaId=' . urlencode( $index ) ),
  62                                 'width'  => $info['width'],
  63                                 'height' => $info['height'],
  64                                 'alt'    => '' ) ) .
  65                         "</p>\n" .
  66                         Xml::element( 'input', array(
  67                                 'type'  => 'hidden',
  68                                 'name'  => 'wpCaptchaId',
  69                                 'id'    => 'wpCaptchaId',
  70                                 'value' => $index ) ) .
  71                         "<p>" .
  72                         Html::element( 'input', array(
  73                                 'name' => 'wpCaptchaWord',
  74                                 'id'   => 'wpCaptchaWord',
  75                                 'required',
  76                                 'tabindex' => 1 ) ) . // tab in before the edit textarea
  77                         "</p>\n";
  78         }
  79
  80         /**
  81          * Select a previously generated captcha image from the queue.
  82          * @fixme subject to race conditions if lots of files vanish
  83          * @return mixed tuple of (salt key, text hash) or false if no image to find
  84          */
  85         function pickImage() {
  86                 global $wgCaptchaDirectory, $wgCaptchaDirectoryLevels;
  87                 return $this->pickImageDir(
  88                         $wgCaptchaDirectory,
  89                         $wgCaptchaDirectoryLevels );
  90         }
  91
  92         function pickImageDir( $directory, $levels ) {
  93                 if ( $levels ) {
  94                         $dirs = array();
  95
  96                         // Check which subdirs are actually present...
  97                         $dir = opendir( $directory );
  98                         while ( false !== ( $entry = readdir( $dir ) ) ) {
  99                                 if ( ctype_xdigit( $entry ) && strlen( $entry ) == 1 ) {
 100                                         $dirs[] = $entry;
 101                                 }
 102                         }
 103                         closedir( $dir );
 104
 105                         $place = mt_rand( 0, count( $dirs ) - 1 );
 106                         // In case all dirs are not filled,
 107                         // cycle through next digits...
 108                         for ( $j = 0; $j < count( $dirs ); $j++ ) {
 109                                 $char = $dirs[( $place + $j ) % count( $dirs )];
 110                                 $return = $this->pickImageDir( "$directory/$char", $levels - 1 );
 111                                 if ( $return ) {
 112                                         return $return;
 113                                 }
 114                         }
 115                         // Didn't find any images in this directory... empty?
 116                         return false;
 117                 } else {
 118                         return $this->pickImageFromDir( $directory );
 119                 }
 120         }
 121
 122         function pickImageFromDir( $directory ) {
 123                 if ( !is_dir( $directory ) ) {
 124                         return false;
 125                 }
 126                 $n = mt_rand( 0, $this->countFiles( $directory ) - 1 );
 127                 $dir = opendir( $directory );
 128
 129                 $count = 0;
 130
 131                 $entry = readdir( $dir );
 132                 $pick = false;
 133                 while ( false !== $entry ) {
 134                         $entry = readdir( $dir );
 135                         if ( preg_match( '/^image_([0-9a-f]+)_([0-9a-f]+)\\.png$/', $entry, $matches ) ) {
 136                                 $size = getimagesize( "$directory/$entry" );
 137                                 $pick = array(
 138                                         'salt' => $matches[1],
 139                                         'hash' => $matches[2],
 140                                         'width' => $size[0],
 141                                         'height' => $size[1],
 142                                         'viewed' => false,
 143                                 );
 144                                 if ( $count++ == $n ) {
 145                                         break;
 146                                 }
 147                         }
 148                 }
 149                 closedir( $dir );
 150                 return $pick;
 151         }
 152
 153         /**
 154          * Count the number of files in a directory.
 155          * @return int
 156          */
 157         function countFiles( $dirname ) {
 158                 $dir = opendir( $dirname );
 159                 $count = 0;
 160                 while ( false !== ( $entry = readdir( $dir ) ) ) {
 161                         if ( $entry != '.' && $entry != '..' ) {
 162                                 $count++;
 163                         }
 164                 }
 165                 closedir( $dir );
 166                 return $count;
 167         }
 168
 169         function showImage() {
 170                 global $wgOut;
 171
 172                 $wgOut->disable();
 173
 174                 $info = $this->retrieveCaptcha();
 175                 if ( $info ) {
 176                         /*
 177                         // Be a little less restrictive for now; in at least some circumstances,
 178                         // Konqueror tries to reload the image even if you haven't navigated
 179                         // away from the page.
 180                         if( $info['viewed'] ) {
 181                                 wfHttpError( 403, 'Access Forbidden', "Can't view captcha image a second time." );
 182                                 return false;
 183                         }
 184                         */
 185
 186                         $info['viewed'] = wfTimestamp();
 187                         $this->storeCaptcha( $info );
 188
 189                         $salt = $info['salt'];
 190                         $hash = $info['hash'];
 191                         $file = $this->imagePath( $salt, $hash );
 192
 193                         if ( file_exists( $file ) ) {
 194                                 global $IP;
 195                                 require_once "$IP/includes/StreamFile.php";
 196                                 header( "Cache-Control: private, s-maxage=0, max-age=3600" );
 197                                 wfStreamFile( $file );
 198                                 return true;
 199                         }
 200                 }
 201                 wfHttpError( 500, 'Internal Error', 'Requested bogus captcha image' );
 202                 return false;
 203         }
 204
 205         function imagePath( $salt, $hash ) {
 206                 global $wgCaptchaDirectory, $wgCaptchaDirectoryLevels;
 207                 $file = $wgCaptchaDirectory;
 208                 $file .= DIRECTORY_SEPARATOR;
 209                 for ( $i = 0; $i < $wgCaptchaDirectoryLevels; $i++ ) {
 210                         $file .= $hash { $i } ;
 211                         $file .= DIRECTORY_SEPARATOR;
 212                 }
 213                 $file .= "image_{$salt}_{$hash}.png";
 214                 return $file;
 215         }
 216
 217         /**
 218          * Show a message asking the user to enter a captcha on edit
 219          * The result will be treated as wiki text
 220          *
 221          * @param $action Action being performed
 222          * @return string
 223          */
 224         function getMessage( $action ) {
 225                 $name = 'fancycaptcha-' . $action;
 226                 $text = wfMsg( $name );
 227                 # Obtain a more tailored message, if possible, otherwise, fall back to
 228                 # the default for edits
 229                 return wfEmptyMsg( $name, $text ) ? wfMsg( 'fancycaptcha-edit' ) : $text;
 230         }
 231
 232         /**
 233          * Delete a solved captcha image, if $wgCaptchaDeleteOnSolve is true.
 234          */
 235         function passCaptcha() {
 236                 global $wgCaptchaDeleteOnSolve;
 237
 238                 $info = $this->retrieveCaptcha(); // get the captcha info before it gets deleted
 239                 $pass = parent::passCaptcha();
 240
 241                 if ( $pass && $wgCaptchaDeleteOnSolve ) {
 242                         $filename = $this->imagePath( $info['salt'], $info['hash'] );
 243                         if ( file_exists( $filename ) ) {
 244                                 unlink( $filename );
 245                         }
 246                 }
 247
 248                 return $pass;
 249         }
 250 }