includes/SpecialUpload.php

   1 <?php
   2 /**
   3  *
   4  * @package MediaWiki
   5  * @subpackage SpecialPage
   6  */
   7
   8 /**
   9  *
  10  */
  11 require_once( 'Image.php' );
  12
  13 /**
  14  * Entry point
  15  */
  16 function wfSpecialUpload() {
  17         global $wgRequest;
  18         $form = new UploadForm( $wgRequest );
  19         $form->execute();
  20 }
  21
  22 /**
  23  *
  24  * @package MediaWiki
  25  * @subpackage SpecialPage
  26  */
  27 class UploadForm {
  28         /**#@+
  29          * @access private
  30          */
  31         var $mUploadAffirm, $mUploadFile, $mUploadDescription, $mIgnoreWarning;
  32         var $mUploadSaveName, $mUploadTempName, $mUploadSize, $mUploadOldVersion;
  33         var $mUploadCopyStatus, $mUploadSource, $mReUpload, $mAction, $mUpload;
  34         var $mOname, $mSessionKey;
  35         /**#@- */
  36
  37         /**
  38          * Constructor : initialise object
  39          * Get data POSTed through the form and assign them to the object
  40          * @param $request Data posted.
  41          */
  42         function UploadForm( &$request ) {
  43                 if( !$request->wasPosted() ) {
  44                         # GET requests just give the main form; no data.
  45                         return;
  46                 }
  47
  48                 $this->mUploadAffirm      = $request->getCheck( 'wpUploadAffirm' );
  49                 $this->mIgnoreWarning     = $request->getCheck( 'wpIgnoreWarning');
  50                 $this->mReUpload          = $request->getCheck( 'wpReUpload' );
  51                 $this->mUpload            = $request->getCheck( 'wpUpload' );
  52
  53                 $this->mUploadDescription = $request->getText( 'wpUploadDescription' );
  54                 $this->mUploadCopyStatus  = $request->getText( 'wpUploadCopyStatus' );
  55                 $this->mUploadSource      = $request->getText( 'wpUploadSource');
  56
  57                 $this->mAction            = $request->getVal( 'action' );
  58
  59                 $this->mSessionKey        = $request->getInt( 'wpSessionKey' );
  60                 if( !empty( $this->mSessionKey ) &&
  61                         isset( $_SESSION['wsUploadData'][$this->mSessionKey] ) ) {
  62                         /**
  63                          * Confirming a temporarily stashed upload.
  64                          * We don't want path names to be forged, so we keep
  65                          * them in the session on the server and just give
  66                          * an opaque key to the user agent.
  67                          */
  68                         $data = $_SESSION['wsUploadData'][$this->mSessionKey];
  69                         $this->mUploadTempName   = $data['mUploadTempName'];
  70                         $this->mUploadSize       = $data['mUploadSize'];
  71                         $this->mOname            = $data['mOname'];
  72                 } else {
  73                         /**
  74                          *Check for a newly uploaded file.
  75                          */
  76                         $this->mUploadTempName = $request->getFileTempName( 'wpUploadFile' );
  77                         $this->mUploadSize     = $request->getFileSize( 'wpUploadFile' );
  78                         $this->mOname          = $request->getFileName( 'wpUploadFile' );
  79                         $this->mSessionKey     = false;
  80                 }
  81         }
  82
  83         /**
  84          * Start doing stuff
  85          * @access public
  86          */
  87         function execute() {
  88                 global $wgUser, $wgOut;
  89                 global $wgDisableUploads;
  90
  91                 /** Show an error message if file upload is disabled */
  92                 if( $wgDisableUploads ) {
  93                         $wgOut->addWikiText( wfMsg( 'uploaddisabled' ) );
  94                         return;
  95                 }
  96
  97                 /** Various rights checks */
  98                 if( ( $wgUser->getID() == 0 )
  99                          OR $wgUser->isBlocked() ) {
 100                         $wgOut->errorpage( 'uploadnologin', 'uploadnologintext' );
 101                         return;
 102                 }
 103                 if( wfReadOnly() ) {
 104                         $wgOut->readOnlyPage();
 105                         return;
 106                 }
 107
 108                 if( $this->mReUpload ) {
 109                         $this->unsaveUploadedFile();
 110                         $this->mainUploadForm();
 111                 } else if ( 'submit' == $this->mAction || $this->mUpload ) {
 112                         $this->processUpload();
 113                 } else {
 114                         $this->mainUploadForm();
 115                 }
 116         }
 117
 118         /* -------------------------------------------------------------- */
 119
 120         /**
 121          * Really do the upload
 122          * Checks are made in SpecialUpload::execute()
 123          * @access private
 124          */
 125         function processUpload() {
 126                 global $wgUser, $wgOut, $wgLang, $wgContLang;
 127                 global $wgUploadDirectory;
 128                 global $wgUseCopyrightUpload, $wgCheckCopyrightUpload;
 129
 130                 /**
 131                  * If there was no filename or a zero size given, give up quick.
 132                  */
 133                 if( ( trim( $this->mOname ) == '' ) || empty( $this->mUploadSize ) ) {
 134                         return $this->mainUploadForm('<li>'.wfMsg( 'emptyfile' ).'</li>');
 135                 }
 136
 137                 /**
 138                  * When using detailed copyright, if user filled field, assume he
 139                  * confirmed the upload
 140                  */
 141                 if ( $wgUseCopyrightUpload ) {
 142                         $this->mUploadAffirm = true;
 143                         if( $wgCheckCopyrightUpload &&
 144                             ( trim( $this->mUploadCopyStatus ) == '' ||
 145                               trim( $this->mUploadSource     ) == '' ) ) {
 146                                 $this->mUploadAffirm = false;
 147                         }
 148                 }
 149
 150                 /** User need to confirm his upload */
 151                 if( !$this->mUploadAffirm ) {
 152                         $this->mainUploadForm( wfMsg( 'noaffirmation' ) );
 153                         return;
 154                 }
 155
 156                 # Chop off any directories in the given filename
 157                 $basename = basename( $this->mOname );
 158
 159                 if( preg_match( '/^(.*)\.([^.]*)$/', $basename, $matches ) ) {
 160                         $partname = $matches[1];
 161                         $ext      = $matches[2];
 162                 } else {
 163                     $partname = $basename;
 164                     $ext = '';
 165                 }
 166
 167                 if ( strlen( $partname ) < 3 ) {
 168                         $this->mainUploadForm( wfMsg( 'minlength' ) );
 169                         return;
 170                 }
 171
 172                 /**
 173                  * Filter out illegal characters, and try to make a legible name
 174                  * out of it. We'll strip some silently that Title would die on.
 175                  */
 176                 $filtered = preg_replace ( "/[^".Title::legalChars()."]|:/", '-', $basename );
 177                 $nt = Title::newFromText( $filtered );
 178                 if( is_null( $nt ) ) {
 179                         return $this->uploadError( wfMsg( 'illegalfilename', htmlspecialchars( $filtered ) ) );
 180                 }
 181                 $nt->setNamespace( NS_IMAGE );
 182                 $this->mUploadSaveName = $nt->getDBkey();
 183
 184                 /**
 185                  * If the image is protected, non-sysop users won't be able
 186                  * to modify it by uploading a new revision.
 187                  */
 188                 if( !$nt->userCanEdit() ) {
 189                         return $this->uploadError( wfMsg( 'protectedpage' ) );
 190                 }
 191
 192                 /* Don't allow users to override the blacklist */
 193                 global $wgStrictFileExtensions;
 194                 global $wgFileExtensions, $wgFileBlacklist;
 195                 if( $this->checkFileExtension( $ext, $wgFileBlacklist ) ||
 196                         ($wgStrictFileExtensions && !$this->checkFileExtension( $ext, $wgFileExtensions ) ) ) {
 197                         return $this->uploadError( wfMsg( 'badfiletype', htmlspecialchars( $ext ) ) );
 198                 }
 199
 200                 /**
 201                  * Look at the contents of the file; if we can recognize the
 202                  * type but it's corrupt or data of the wrong type, we should
 203                  * probably not accept it.
 204                  */
 205                 if( !$this->verify( $this->mUploadTempName, $ext ) ) {
 206                         return $this->uploadError( wfMsg( 'uploadcorrupt' ) );
 207                 }
 208
 209                 /**
 210                  * Check for non-fatal conditions
 211                  */
 212                 if ( ! $this->mIgnoreWarning ) {
 213                         $warning = '';
 214                         if( $this->mUploadSaveName != ucfirst( $filtered ) ) {
 215                                 $warning .=  '<li>'.wfMsg( 'badfilename', htmlspecialchars( $this->mUploadSaveName ) ).'</li>';
 216                         }
 217
 218                         global $wgCheckFileExtensions;
 219                         if ( $wgCheckFileExtensions ) {
 220                                 if ( ! $this->checkFileExtension( $ext, $wgFileExtensions ) ) {
 221                                         $warning .= '<li>'.wfMsg( 'badfiletype', htmlspecialchars( $ext ) ).'</li>';
 222                                 }
 223                         }
 224
 225                         global $wgUploadSizeWarning;
 226                         if ( $wgUploadSizeWarning && ( $this->mUploadSize > $wgUploadSizeWarning ) ) {
 227                                 $warning .= '<li>'.wfMsg( 'largefile' ).'</li>';
 228                         }
 229                         if ( $this->mUploadSize == 0 ) {
 230                                 $warning .= '<li>'.wfMsg( 'emptyfile' ).'</li>';
 231                         }
 232
 233                         if( $nt->getArticleID() ) {
 234                                 global $wgUser;
 235                                 $sk = $wgUser->getSkin();
 236                                 $dlink = $sk->makeKnownLinkObj( $nt );
 237                                 $warning .= '<li>'.wfMsg( 'fileexists', $dlink ).'</li>';
 238                         }
 239
 240                         if( $warning != '' ) {
 241                                 /**
 242                                  * Stash the file in a temporary location; the user can choose
 243                                  * to let it through and we'll complete the upload then.
 244                                  */
 245                                 return $this->uploadWarning($warning);
 246                         }
 247                 }
 248
 249                 /**
 250                  * Try actually saving the thing...
 251                  * It will show an error form on failure.
 252                  */
 253                 if( $this->saveUploadedFile( $this->mUploadSaveName,
 254                                              $this->mUploadTempName,
 255                                              !empty( $this->mSessionKey ) ) ) {
 256                         /**
 257                          * Update the upload log and create the description page
 258                          * if it's a new file.
 259                          */
 260                         wfRecordUpload( $this->mUploadSaveName,
 261                                         $this->mUploadOldVersion,
 262                                         $this->mUploadSize,
 263                                         $this->mUploadDescription,
 264                                         $this->mUploadCopyStatus,
 265                                         $this->mUploadSource );
 266                         $this->showSuccess();
 267                 }
 268         }
 269
 270         /**
 271          * Move the uploaded file from its temporary location to the final
 272          * destination. If a previous version of the file exists, move
 273          * it into the archive subdirectory.
 274          *
 275          * @todo If the later save fails, we may have disappeared the original file.
 276          *
 277          * @param string $saveName
 278          * @param string $tempName full path to the temporary file
 279          * @param bool $useRename if true, doesn't check that the source file
 280          *                        is a PHP-managed upload temporary
 281          */
 282         function saveUploadedFile( $saveName, $tempName, $useRename = false ) {
 283                 global $wgUploadDirectory, $wgOut;
 284
 285                 $dest = wfImageDir( $saveName );
 286                 $archive = wfImageArchiveDir( $saveName );
 287                 $this->mSavedFile = "{$dest}/{$saveName}";
 288
 289                 if( is_file( $this->mSavedFile ) ) {
 290                         $this->mUploadOldVersion = gmdate( 'YmdHis' ) . "!{$saveName}";
 291
 292                         if( !rename( $this->mSavedFile, "${archive}/{$this->mUploadOldVersion}" ) ) {
 293                                 $wgOut->fileRenameError( $this->mSavedFile,
 294                                   "${archive}/{$this->mUploadOldVersion}" );
 295                                 return false;
 296                         }
 297                 } else {
 298                         $this->mUploadOldVersion = '';
 299                 }
 300
 301                 if( $useRename ) {
 302                         if( !rename( $tempName, $this->mSavedFile ) ) {
 303                                 $wgOut->fileCopyError( $tempName, $this->mSavedFile );
 304                                 return false;
 305                         }
 306                 } else {
 307                         if( !move_uploaded_file( $tempName, $this->mSavedFile ) ) {
 308                                 $wgOut->fileCopyError( $tempName, $this->mSavedFile );
 309                                 return false;
 310                         }
 311                 }
 312                 chmod( $this->mSavedFile, 0644 );
 313                 return true;
 314         }
 315
 316         /**
 317          * Stash a file in a temporary directory for later processing
 318          * after the user has confirmed it.
 319          *
 320          * If the user doesn't explicitly cancel or accept, these files
 321          * can accumulate in the temp directory.
 322          *
 323          * @param string $saveName - the destination filename
 324          * @param string $tempName - the source temporary file to save
 325          * @return string - full path the stashed file, or false on failure
 326          * @access private
 327          */
 328         function saveTempUploadedFile( $saveName, $tempName ) {
 329                 global $wgOut;
 330
 331                 $archive = wfImageArchiveDir( $saveName, 'temp' );
 332                 $stash = $archive . '/' . gmdate( "YmdHis" ) . '!' . $saveName;
 333
 334                 if ( !move_uploaded_file( $tempName, $stash ) ) {
 335                         $wgOut->fileCopyError( $tempName, $stash );
 336                         return false;
 337                 }
 338
 339                 return $stash;
 340         }
 341
 342         /**
 343          * Stash a file in a temporary directory for later processing,
 344          * and save the necessary descriptive info into the session.
 345          * Returns a key value which will be passed through a form
 346          * to pick up the path info on a later invocation.
 347          *
 348          * @return int
 349          * @access private
 350          */
 351         function stashSession() {
 352                 $stash = $this->saveTempUploadedFile(
 353                         $this->mUploadSaveName, $this->mUploadTempName );
 354
 355                 if( !$stash ) {
 356                         # Couldn't save the file.
 357                         return false;
 358                 }
 359
 360                 $key = mt_rand( 0, 0x7fffffff );
 361                 $_SESSION['wsUploadData'][$key] = array(
 362                         'mUploadTempName' => $stash,
 363                         'mUploadSize'     => $this->mUploadSize,
 364                         'mOname'          => $this->mOname );
 365                 return $key;
 366         }
 367
 368         /**
 369          * Remove a temporarily kept file stashed by saveTempUploadedFile().
 370          * @access private
 371          */
 372         function unsaveUploadedFile() {
 373                 if ( ! @unlink( $this->mUploadTempName ) ) {
 374                         $wgOut->fileDeleteError( $this->mUploadTempName );
 375                 }
 376         }
 377
 378         /* -------------------------------------------------------------- */
 379
 380         /**
 381          * Show some text and linkage on successful upload.
 382          * @access private
 383          */
 384         function showSuccess() {
 385                 global $wgUser, $wgOut, $wgContLang;
 386
 387                 $sk = $wgUser->getSkin();
 388                 $ilink = $sk->makeMediaLink( $this->mUploadSaveName, Image::wfImageUrl( $this->mUploadSaveName ) );
 389                 $dname = $wgContLang->getNsText( Namespace::getImage() ) . ':'.$this->mUploadSaveName;
 390                 $dlink = $sk->makeKnownLink( $dname, $dname );
 391
 392                 $wgOut->addHTML( '<h2>' . wfMsg( 'successfulupload' ) . "</h2>\n" );
 393                 $text = wfMsg( 'fileuploaded', $ilink, $dlink );
 394                 $wgOut->addHTML( '<p>'.$text."\n" );
 395                 $wgOut->returnToMain( false );
 396         }
 397
 398         /**
 399          * @param string $error as HTML
 400          * @access private
 401          */
 402         function uploadError( $error ) {
 403                 global $wgOut;
 404                 $sub = wfMsg( 'uploadwarning' );
 405                 $wgOut->addHTML( "<h2>{$sub}</h2>\n" );
 406                 $wgOut->addHTML( "<h4 class='error'>{$error}</h4>\n" );
 407         }
 408
 409         /**
 410          * There's something wrong with this file, not enough to reject it
 411          * totally but we require manual intervention to save it for real.
 412          * Stash it away, then present a form asking to confirm or cancel.
 413          *
 414          * @param string $warning as HTML
 415          * @access private
 416          */
 417         function uploadWarning( $warning ) {
 418                 global $wgOut, $wgUser, $wgLang, $wgUploadDirectory, $wgRequest;
 419                 global $wgUseCopyrightUpload;
 420
 421                 $this->mSessionKey = $this->stashSession();
 422                 if( !$this->mSessionKey ) {
 423                         # Couldn't save file; an error has been displayed so let's go.
 424                         return;
 425                 }
 426
 427                 $sub = wfMsg( 'uploadwarning' );
 428                 $wgOut->addHTML( "<h2>{$sub}</h2>\n" );
 429                 $wgOut->addHTML( "<ul class='warning'>{$warning}</ul><br/>\n" );
 430
 431                 $save = wfMsg( 'savefile' );
 432                 $reupload = wfMsg( 'reupload' );
 433                 $iw = wfMsg( 'ignorewarning' );
 434                 $reup = wfMsg( 'reuploaddesc' );
 435                 $titleObj = Title::makeTitle( NS_SPECIAL, 'Upload' );
 436                 $action = $titleObj->escapeLocalURL( 'action=submit' );
 437
 438                 if ( $wgUseCopyrightUpload )
 439                 {
 440                         $copyright =  "
 441         <input type='hidden' name=\"wpUploadCopyStatus\" value=\"" . htmlspecialchars( $this->mUploadCopyStatus ) . "\" />
 442         <input type='hidden' name=\"wpUploadSource\" value=\"" . htmlspecialchars( $this->mUploadSource ) . "\" />
 443         ";
 444                 } else {
 445                         $copyright = "";
 446                 }
 447
 448                 $wgOut->addHTML( "
 449         <form id=\"uploadwarning\" method=\"post\" enctype=\"multipart/form-data\"
 450         action=\"{$action}\">
 451         <input type=hidden name=\"wpUploadAffirm\" value=\"1\" />
 452         <input type=hidden name=\"wpIgnoreWarning\" value=\"1\" />
 453         <input type=hidden name=\"wpSessionKey\" value=\"" . htmlspecialchars( $this->mSessionKey ) . "\" />
 454         <input type=hidden name=\"wpUploadDescription\" value=\"" . htmlspecialchars( $this->mUploadDescription ) . "\" />
 455         {$copyright}
 456         <table border='0'><tr>
 457         <tr><td align='right'>
 458         <input tabindex='2' type='submit' name=\"wpUpload\" value=\"{$save}\" />
 459         </td><td align='left'>{$iw}</td></tr>
 460         <tr><td align='right'>
 461         <input tabindex='2' type='submit' name=\"wpReUpload\" value=\"{$reupload}\" />
 462         </td><td align='left'>{$reup}</td></tr></table></form>\n" );
 463         }
 464
 465         /**
 466          * Displays the main upload form, optionally with a highlighted
 467          * error message up at the top.
 468          *
 469          * @param string $msg as HTML
 470          * @access private
 471          */
 472         function mainUploadForm( $msg='' ) {
 473                 global $wgOut, $wgUser, $wgLang, $wgUploadDirectory, $wgRequest;
 474                 global $wgUseCopyrightUpload;
 475
 476                 if ( '' != $msg ) {
 477                         $sub = wfMsg( 'uploaderror' );
 478                         $wgOut->addHTML( "<h2>{$sub}</h2>\n" .
 479                           "<h4 class='error'>{$msg}</h4>\n" );
 480                 } else {
 481                         $sub = wfMsg( 'uploadfile' );
 482                         $wgOut->addHTML( "<h2>{$sub}</h2>\n" );
 483                 }
 484                 $wgOut->addWikiText( wfMsg( 'uploadtext' ) );
 485                 $sk = $wgUser->getSkin();
 486
 487                 $fn = wfMsg( 'filename' );
 488                 $fd = wfMsg( 'filedesc' );
 489                 $ulb = wfMsg( 'uploadbtn' );
 490
 491                 $clink = $sk->makeKnownLink( wfMsgForContent( 'copyrightpage' ),
 492                   wfMsg( 'copyrightpagename' ) );
 493                 $ca = wfMsg( 'affirmation', $clink );
 494                 $iw = wfMsg( 'ignorewarning' );
 495
 496                 $titleObj = Title::makeTitle( NS_SPECIAL, 'Upload' );
 497                 $action = $titleObj->escapeLocalURL();
 498
 499                 $source = "
 500         <td align='right'>
 501         <input tabindex='3' type='checkbox' name=\"wpUploadAffirm\" value=\"1\" id=\"wpUploadAffirm\" />
 502         </td><td align='left'><label for=\"wpUploadAffirm\">{$ca}</label></td>
 503         " ;
 504                 if ( $wgUseCopyrightUpload )
 505                   {
 506                         $source = "
 507         <td align='right' nowrap='nowrap'>" . wfMsg ( 'filestatus' ) . ":</td>
 508         <td><input tabindex='3' type='text' name=\"wpUploadCopyStatus\" value=\"" .
 509         htmlspecialchars($this->mUploadCopyStatus). "\" size='40' /></td>
 510         </tr><tr>
 511         <td align='right'>". wfMsg ( 'filesource' ) . ":</td>
 512         <td><input tabindex='4' type='text' name=\"wpUploadSource\" value=\"" .
 513         htmlspecialchars($this->mUploadSource). "\" size='40' /></td>
 514         " ;
 515                   }
 516
 517                 $wgOut->addHTML( "
 518         <form id=\"upload\" method=\"post\" enctype=\"multipart/form-data\"
 519         action=\"{$action}\">
 520         <table border='0'><tr>
 521         <td align='right'>{$fn}:</td><td align='left'>
 522         <input tabindex='1' type='file' name=\"wpUploadFile\" size='40' />
 523         </td></tr><tr>
 524         <td align='right'>{$fd}:</td><td align='left'>
 525         <input tabindex='2' type='text' name=\"wpUploadDescription\" value=\""
 526           . htmlspecialchars( $this->mUploadDescription ) . "\" size='40' />
 527         </td></tr><tr>
 528         {$source}
 529         </tr>
 530         <tr><td></td><td align='left'>
 531         <input tabindex='5' type='submit' name=\"wpUpload\" value=\"{$ulb}\" />
 532         </td></tr></table></form>\n" );
 533         }
 534
 535         /* -------------------------------------------------------------- */
 536
 537         /**
 538          * Perform case-insensitive match against a list of file extensions.
 539          * Returns true if the extension is in the list.
 540          *
 541          * @param string $ext
 542          * @param array $list
 543          * @return bool
 544          */
 545         function checkFileExtension( $ext, $list ) {
 546                 return in_array( strtolower( $ext ), $list );
 547         }
 548
 549         /**
 550          * Returns false if the file is of a known type but can't be recognized,
 551          * indicating a corrupt file.
 552          * Returns true otherwise; unknown file types are not checked if given
 553          * with an unrecognized extension.
 554          *
 555          * @param string $tmpfile Pathname to the temporary upload file
 556          * @param string $extension The filename extension that the file is to be served with
 557          * @return bool
 558          */
 559         function verify( $tmpfile, $extension ) {
 560                 if( $this->triggersIEbug( $tmpfile ) ) {
 561                         return false;
 562                 }
 563
 564                 $fname = 'SpecialUpload::verify';
 565                 $mergeExtensions = array(
 566                         'jpg' => 'jpeg',
 567                         'tif' => 'tiff' );
 568                 $extensionTypes = array(
 569                         # See http://www.php.net/getimagesize
 570                         1 => 'gif',
 571                         2 => 'jpeg',
 572                         3 => 'png',
 573                         4 => 'swf',
 574                         5 => 'psd',
 575                         6 => 'bmp',
 576                         7 => 'tiff',
 577                         8 => 'tiff',
 578                         9 => 'jpc',
 579                         10 => 'jp2',
 580                         11 => 'jpx',
 581                         12 => 'jb2',
 582                         13 => 'swc',
 583                         14 => 'iff',
 584                         15 => 'wbmp',
 585                         16 => 'xbm' );
 586
 587                 $extension = strtolower( $extension );
 588                 if( isset( $mergeExtensions[$extension] ) ) {
 589                         $extension = $mergeExtensions[$extension];
 590                 }
 591                 wfDebug( "$fname: Testing file '$tmpfile' with given extension '$extension'\n" );
 592
 593                 if( !in_array( $extension, $extensionTypes ) ) {
 594                         # Not a recognized image type. We don't know how to verify these.
 595                         # They're allowed by policy or they wouldn't get this far, so we'll
 596                         # let them slide for now.
 597                         wfDebug( "$fname: Unknown extension; passing.\n" );
 598                         return true;
 599                 }
 600
 601                 $data = @getimagesize( $tmpfile );
 602                 if( false === $data ) {
 603                         # Didn't recognize the image type.
 604                         # Either the image is corrupt or someone's slipping us some
 605                         # bogus data such as HTML+JavaScript trying to take advantage
 606                         # of an Internet Explorer security flaw.
 607                         wfDebug( "$fname: getimagesize() doesn't recognize the file; rejecting.\n" );
 608                         return false;
 609                 }
 610
 611                 $imageType = $data[2];
 612                 if( !isset( $extensionTypes[$imageType] ) ) {
 613                         # Now we're kind of confused. Perhaps new image types added
 614                         # to PHP's support that we don't know about.
 615                         # We'll let these slide for now.
 616                         wfDebug( "$fname: getimagesize() knows the file, but we don't recognize the type; passing.\n" );
 617                         return true;
 618                 }
 619
 620                 $ext = strtolower( $extension );
 621                 if( $extension != $extensionTypes[$imageType] ) {
 622                         # The given filename extension doesn't match the
 623                         # file type. Probably just a mistake, but it's a stupid
 624                         # one and we shouldn't let it pass. KILL THEM!
 625                         wfDebug( "$fname: file extension does not match recognized type; rejecting.\n" );
 626                         return false;
 627                 }
 628
 629                 wfDebug( "$fname: all clear; passing.\n" );
 630                 return true;
 631         }
 632
 633         /**
 634          * Internet Explorer for Windows performs some really stupid file type
 635          * autodetection which can cause it to interpret valid image files as HTML
 636          * and potentially execute JavaScript, creating a cross-site scripting
 637          * attack vectors.
 638          *
 639          * Returns true if IE is likely to mistake the given file for HTML.
 640          *
 641          * @param string $filename
 642          * @return bool
 643          */
 644         function triggersIEbug( $filename ) {
 645                 $file = fopen( $filename, 'rb' );
 646                 $chunk = strtolower( fread( $file, 200 ) );
 647                 fclose( $file );
 648
 649                 $tags = array( '<html', '<head', '<body', '<script' );
 650                 foreach( $tags as $tag ) {
 651                         if( false !== strpos( $chunk, $tag ) ) {
 652                                 return true;
 653                         }
 654                 }
 655                 return false;
 656         }
 657 }
 658 ?>