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