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                         Html::element( 'img', array(
  61                                 'src'    => $title->getLocalUrl( 'wpCaptchaId=' . urlencode( $index ) ),
  62                                 'width'  => $info['width'],
  63                                 'height' => $info['height'],
  64                                 'alt'    => '' ) ) .
  65                         "</p>\n" .
  66                         Html::element( 'input', array(
  67                                 'type'  => 'hidden',
  68                                 'name'  => 'wpCaptchaId',
  69                                 'id'    => 'wpCaptchaId',
  70                                 'value' => $index ) ) .
  71                         '<p>' .
  72                         Html::element( 'label', array(
  73                                 'for' => 'wpCaptchaWord',
  74                         ), parent::getMessage( 'label' ) . wfMsg( 'colon-separator' ) ) .
  75                         Html::element( 'input', array(
  76                                 'name' => 'wpCaptchaWord',
  77                                 'id'   => 'wpCaptchaWord',
  78                                 'type' => 'text',
  79                                 'autocorrect' => 'off',
  80                                 'autocapitalize' => 'off',
  81                                 'required' => 'required',
  82                                 'tabindex' => 1 ) ) . // tab in before the edit textarea
  83                         "</p>\n";
  84         }
  85
  86         /**
  87          * Select a previously generated captcha image from the queue.
  88          * @fixme subject to race conditions if lots of files vanish
  89          * @return mixed tuple of (salt key, text hash) or false if no image to find
  90          */
  91         function pickImage() {
  92                 global $wgCaptchaDirectory, $wgCaptchaDirectoryLevels;
  93                 return $this->pickImageDir(
  94                         $wgCaptchaDirectory,
  95                         $wgCaptchaDirectoryLevels );
  96         }
  97
  98         function pickImageDir( $directory, $levels ) {
  99                 if ( $levels ) {
 100                         $dirs = array();
 101
 102                         // Check which subdirs are actually present...
 103                         $dir = opendir( $directory );
 104                         if ( !$dir ) {
 105                                 return false;
 106                         }
 107                         while ( false !== ( $entry = readdir( $dir ) ) ) {
 108                                 if ( ctype_xdigit( $entry ) && strlen( $entry ) == 1 ) {
 109                                         $dirs[] = $entry;
 110                                 }
 111                         }
 112                         closedir( $dir );
 113
 114                         $place = mt_rand( 0, count( $dirs ) - 1 );
 115                         // In case all dirs are not filled,
 116                         // cycle through next digits...
 117                         for ( $j = 0; $j < count( $dirs ); $j++ ) {
 118                                 $char = $dirs[( $place + $j ) % count( $dirs )];
 119                                 $return = $this->pickImageDir( "$directory/$char", $levels - 1 );
 120                                 if ( $return ) {
 121                                         return $return;
 122                                 }
 123                         }
 124                         // Didn't find any images in this directory... empty?
 125                         return false;
 126                 } else {
 127                         return $this->pickImageFromDir( $directory );
 128                 }
 129         }
 130
 131         function pickImageFromDir( $directory ) {
 132                 if ( !is_dir( $directory ) ) {
 133                         return false;
 134                 }
 135                 $n = mt_rand( 0, $this->countFiles( $directory ) - 1 );
 136                 $dir = opendir( $directory );
 137
 138                 $count = 0;
 139
 140                 $entry = readdir( $dir );
 141                 $pick = false;
 142                 while ( false !== $entry ) {
 143                         $entry = readdir( $dir );
 144                         if ( preg_match( '/^image_([0-9a-f]+)_([0-9a-f]+)\\.png$/', $entry, $matches ) ) {
 145                                 $size = getimagesize( "$directory/$entry" );
 146                                 $pick = array(
 147                                         'salt' => $matches[1],
 148                                         'hash' => $matches[2],
 149                                         'width' => $size[0],
 150                                         'height' => $size[1],
 151                                         'viewed' => false,
 152                                 );
 153                                 if ( $count++ == $n ) {
 154                                         break;
 155                                 }
 156                         }
 157                 }
 158                 closedir( $dir );
 159                 return $pick;
 160         }
 161
 162         /**
 163          * Count the number of files in a directory.
 164          * @return int
 165          */
 166         function countFiles( $dirname ) {
 167                 $dir = opendir( $dirname );
 168                 $count = 0;
 169                 while ( false !== ( $entry = readdir( $dir ) ) ) {
 170                         if ( $entry != '.' && $entry != '..' ) {
 171                                 $count++;
 172                         }
 173                 }
 174                 closedir( $dir );
 175                 return $count;
 176         }
 177
 178         function showImage() {
 179                 global $wgOut;
 180
 181                 $wgOut->disable();
 182
 183                 $info = $this->retrieveCaptcha();
 184                 if ( $info ) {
 185                         /*
 186                         // Be a little less restrictive for now; in at least some circumstances,
 187                         // Konqueror tries to reload the image even if you haven't navigated
 188                         // away from the page.
 189                         if( $info['viewed'] ) {
 190                                 wfHttpError( 403, 'Access Forbidden', "Can't view captcha image a second time." );
 191                                 return false;
 192                         }
 193                         */
 194
 195                         $info['viewed'] = wfTimestamp();
 196                         $this->storeCaptcha( $info );
 197
 198                         $salt = $info['salt'];
 199                         $hash = $info['hash'];
 200                         $file = $this->imagePath( $salt, $hash );
 201
 202                         if ( file_exists( $file ) ) {
 203                                 global $IP;
 204                                 require_once "$IP/includes/StreamFile.php";
 205                                 header( "Cache-Control: private, s-maxage=0, max-age=3600" );
 206                                 wfStreamFile( $file );
 207                                 return true;
 208                         }
 209                 }
 210                 wfHttpError( 500, 'Internal Error', 'Requested bogus captcha image' );
 211                 return false;
 212         }
 213
 214         function imagePath( $salt, $hash ) {
 215                 global $wgCaptchaDirectory, $wgCaptchaDirectoryLevels;
 216                 $file = $wgCaptchaDirectory;
 217                 $file .= DIRECTORY_SEPARATOR;
 218                 for ( $i = 0; $i < $wgCaptchaDirectoryLevels; $i++ ) {
 219                         $file .= $hash { $i } ;
 220                         $file .= DIRECTORY_SEPARATOR;
 221                 }
 222                 $file .= "image_{$salt}_{$hash}.png";
 223                 return $file;
 224         }
 225
 226         /**
 227          * Show a message asking the user to enter a captcha on edit
 228          * The result will be treated as wiki text
 229          *
 230          * @param $action Action being performed
 231          * @return string
 232          */
 233         function getMessage( $action ) {
 234                 $name = 'fancycaptcha-' . $action;
 235                 $text = wfMsg( $name );
 236                 # Obtain a more tailored message, if possible, otherwise, fall back to
 237                 # the default for edits
 238                 return wfEmptyMsg( $name, $text ) ? wfMsg( 'fancycaptcha-edit' ) : $text;
 239         }
 240
 241         /**
 242          * Delete a solved captcha image, if $wgCaptchaDeleteOnSolve is true.
 243          */
 244         function passCaptcha() {
 245                 global $wgCaptchaDeleteOnSolve;
 246
 247                 $info = $this->retrieveCaptcha(); // get the captcha info before it gets deleted
 248                 $pass = parent::passCaptcha();
 249
 250                 if ( $pass && $wgCaptchaDeleteOnSolve ) {
 251                         $filename = $this->imagePath( $info['salt'], $info['hash'] );
 252                         if ( file_exists( $filename ) ) {
 253                                 unlink( $filename );
 254                         }
 255                 }
 256
 257                 return $pass;
 258         }
 259 }