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                 /**
 160                  * We'll want to blacklist against *any* 'extension', and use
 161                  * only the final one for the whitelist.
 162                  */
 163                 list( $partname, $ext ) = $this->splitExtensions( $basename );
 164                 if( count( $ext ) ) {
 165                         $finalExt = $ext[count( $ext ) - 1];
 166                 } else {
 167                         $finalExt = '';
 168                 }
 169                 $fullExt = implode( '.', $ext );
 170
 171                 if ( strlen( $partname ) < 3 ) {
 172                         $this->mainUploadForm( wfMsg( 'minlength' ) );
 173                         return;
 174                 }
 175
 176                 /**
 177                  * Filter out illegal characters, and try to make a legible name
 178                  * out of it. We'll strip some silently that Title would die on.
 179                  */
 180                 $filtered = preg_replace ( "/[^".Title::legalChars()."]|:/", '-', $basename );
 181                 $nt = Title::newFromText( $filtered );
 182                 if( is_null( $nt ) ) {
 183                         return $this->uploadError( wfMsg( 'illegalfilename', htmlspecialchars( $filtered ) ) );
 184                 }
 185                 $nt =& Title::makeTitle( NS_IMAGE, $nt->getDBkey() );
 186                 $this->mUploadSaveName = $nt->getDBkey();
 187
 188                 /**
 189                  * If the image is protected, non-sysop users won't be able
 190                  * to modify it by uploading a new revision.
 191                  */
 192                 if( !$nt->userCanEdit() ) {
 193                         return $this->uploadError( wfMsg( 'protectedpage' ) );
 194                 }
 195
 196                 /* Don't allow users to override the blacklist */
 197                 global $wgStrictFileExtensions;
 198                 global $wgFileExtensions, $wgFileBlacklist;
 199                 if( $this->checkFileExtensionList( $ext, $wgFileBlacklist ) ||
 200                         ($wgStrictFileExtensions &&
 201                                 !$this->checkFileExtension( $finalExt, $wgFileExtensions ) ) ) {
 202                         return $this->uploadError( wfMsg( 'badfiletype', htmlspecialchars( $fullExt ) ) );
 203                 }
 204
 205                 /**
 206                  * Look at the contents of the file; if we can recognize the
 207                  * type but it's corrupt or data of the wrong type, we should
 208                  * probably not accept it.
 209                  */
 210                 if( !$this->verify( $this->mUploadTempName, $finalExt ) ) {
 211                         return $this->uploadError( wfMsg( 'uploadcorrupt' ) );
 212                 }
 213
 214                 /**
 215                  * Check for non-fatal conditions
 216                  */
 217                 if ( ! $this->mIgnoreWarning ) {
 218                         $warning = '';
 219                         if( $this->mUploadSaveName != ucfirst( $filtered ) ) {
 220                                 $warning .=  '<li>'.wfMsg( 'badfilename', htmlspecialchars( $this->mUploadSaveName ) ).'</li>';
 221                         }
 222
 223                         global $wgCheckFileExtensions;
 224                         if ( $wgCheckFileExtensions ) {
 225                                 if ( ! $this->checkFileExtension( $finalExt, $wgFileExtensions ) ) {
 226                                         $warning .= '<li>'.wfMsg( 'badfiletype', htmlspecialchars( $fullExt ) ).'</li>';
 227                                 }
 228                         }
 229
 230                         global $wgUploadSizeWarning;
 231                         if ( $wgUploadSizeWarning && ( $this->mUploadSize > $wgUploadSizeWarning ) ) {
 232                                 $warning .= '<li>'.wfMsg( 'largefile' ).'</li>';
 233                         }
 234                         if ( $this->mUploadSize == 0 ) {
 235                                 $warning .= '<li>'.wfMsg( 'emptyfile' ).'</li>';
 236                         }
 237
 238                         if( $nt->getArticleID() ) {
 239                                 global $wgUser;
 240                                 $sk = $wgUser->getSkin();
 241                                 $dlink = $sk->makeKnownLinkObj( $nt );
 242                                 $warning .= '<li>'.wfMsg( 'fileexists', $dlink ).'</li>';
 243                         }
 244
 245                         if( $warning != '' ) {
 246                                 /**
 247                                  * Stash the file in a temporary location; the user can choose
 248                                  * to let it through and we'll complete the upload then.
 249                                  */
 250                                 return $this->uploadWarning($warning);
 251                         }
 252                 }
 253
 254                 /**
 255                  * Try actually saving the thing...
 256                  * It will show an error form on failure.
 257                  */
 258                 if( $this->saveUploadedFile( $this->mUploadSaveName,
 259                                              $this->mUploadTempName,
 260                                              !empty( $this->mSessionKey ) ) ) {
 261                         /**
 262                          * Update the upload log and create the description page
 263                          * if it's a new file.
 264                          */
 265                         wfRecordUpload( $this->mUploadSaveName,
 266                                         $this->mUploadOldVersion,
 267                                         $this->mUploadSize,
 268                                         $this->mUploadDescription,
 269                                         $this->mUploadCopyStatus,
 270                                         $this->mUploadSource );
 271                         $this->showSuccess();
 272                 }
 273         }
 274
 275         /**
 276          * Move the uploaded file from its temporary location to the final
 277          * destination. If a previous version of the file exists, move
 278          * it into the archive subdirectory.
 279          *
 280          * @todo If the later save fails, we may have disappeared the original file.
 281          *
 282          * @param string $saveName
 283          * @param string $tempName full path to the temporary file
 284          * @param bool $useRename if true, doesn't check that the source file
 285          *                        is a PHP-managed upload temporary
 286          */
 287         function saveUploadedFile( $saveName, $tempName, $useRename = false ) {
 288                 global $wgUploadDirectory, $wgOut;
 289
 290                 $dest = wfImageDir( $saveName );
 291                 $archive = wfImageArchiveDir( $saveName );
 292                 $this->mSavedFile = "{$dest}/{$saveName}";
 293
 294                 if( is_file( $this->mSavedFile ) ) {
 295                         $this->mUploadOldVersion = gmdate( 'YmdHis' ) . "!{$saveName}";
 296
 297                         if( !rename( $this->mSavedFile, "${archive}/{$this->mUploadOldVersion}" ) ) {
 298                                 $wgOut->fileRenameError( $this->mSavedFile,
 299                                   "${archive}/{$this->mUploadOldVersion}" );
 300                                 return false;
 301                         }
 302                 } else {
 303                         $this->mUploadOldVersion = '';
 304                 }
 305
 306                 if( $useRename ) {
 307                         if( !rename( $tempName, $this->mSavedFile ) ) {
 308                                 $wgOut->fileCopyError( $tempName, $this->mSavedFile );
 309                                 return false;
 310                         }
 311                 } else {
 312                         if( !move_uploaded_file( $tempName, $this->mSavedFile ) ) {
 313                                 $wgOut->fileCopyError( $tempName, $this->mSavedFile );
 314                                 return false;
 315                         }
 316                 }
 317                 chmod( $this->mSavedFile, 0644 );
 318                 return true;
 319         }
 320
 321         /**
 322          * Stash a file in a temporary directory for later processing
 323          * after the user has confirmed it.
 324          *
 325          * If the user doesn't explicitly cancel or accept, these files
 326          * can accumulate in the temp directory.
 327          *
 328          * @param string $saveName - the destination filename
 329          * @param string $tempName - the source temporary file to save
 330          * @return string - full path the stashed file, or false on failure
 331          * @access private
 332          */
 333         function saveTempUploadedFile( $saveName, $tempName ) {
 334                 global $wgOut;
 335
 336                 $archive = wfImageArchiveDir( $saveName, 'temp' );
 337                 $stash = $archive . '/' . gmdate( "YmdHis" ) . '!' . $saveName;
 338
 339                 if ( !move_uploaded_file( $tempName, $stash ) ) {
 340                         $wgOut->fileCopyError( $tempName, $stash );
 341                         return false;
 342                 }
 343
 344                 return $stash;
 345         }
 346
 347         /**
 348          * Stash a file in a temporary directory for later processing,
 349          * and save the necessary descriptive info into the session.
 350          * Returns a key value which will be passed through a form
 351          * to pick up the path info on a later invocation.
 352          *
 353          * @return int
 354          * @access private
 355          */
 356         function stashSession() {
 357                 $stash = $this->saveTempUploadedFile(
 358                         $this->mUploadSaveName, $this->mUploadTempName );
 359
 360                 if( !$stash ) {
 361                         # Couldn't save the file.
 362                         return false;
 363                 }
 364
 365                 $key = mt_rand( 0, 0x7fffffff );
 366                 $_SESSION['wsUploadData'][$key] = array(
 367                         'mUploadTempName' => $stash,
 368                         'mUploadSize'     => $this->mUploadSize,
 369                         'mOname'          => $this->mOname );
 370                 return $key;
 371         }
 372
 373         /**
 374          * Remove a temporarily kept file stashed by saveTempUploadedFile().
 375          * @access private
 376          */
 377         function unsaveUploadedFile() {
 378                 if ( ! @unlink( $this->mUploadTempName ) ) {
 379                         $wgOut->fileDeleteError( $this->mUploadTempName );
 380                 }
 381         }
 382
 383         /* -------------------------------------------------------------- */
 384
 385         /**
 386          * Show some text and linkage on successful upload.
 387          * @access private
 388          */
 389         function showSuccess() {
 390                 global $wgUser, $wgOut, $wgContLang;
 391
 392                 $sk = $wgUser->getSkin();
 393                 $ilink = $sk->makeMediaLink( $this->mUploadSaveName, Image::wfImageUrl( $this->mUploadSaveName ) );
 394                 $dname = $wgContLang->getNsText( Namespace::getImage() ) . ':'.$this->mUploadSaveName;
 395                 $dlink = $sk->makeKnownLink( $dname, $dname );
 396
 397                 $wgOut->addHTML( '<h2>' . wfMsg( 'successfulupload' ) . "</h2>\n" );
 398                 $text = wfMsg( 'fileuploaded', $ilink, $dlink );
 399                 $wgOut->addHTML( '<p>'.$text."\n" );
 400                 $wgOut->returnToMain( false );
 401         }
 402
 403         /**
 404          * @param string $error as HTML
 405          * @access private
 406          */
 407         function uploadError( $error ) {
 408                 global $wgOut;
 409                 $sub = wfMsg( 'uploadwarning' );
 410                 $wgOut->addHTML( "<h2>{$sub}</h2>\n" );
 411                 $wgOut->addHTML( "<h4 class='error'>{$error}</h4>\n" );
 412         }
 413
 414         /**
 415          * There's something wrong with this file, not enough to reject it
 416          * totally but we require manual intervention to save it for real.
 417          * Stash it away, then present a form asking to confirm or cancel.
 418          *
 419          * @param string $warning as HTML
 420          * @access private
 421          */
 422         function uploadWarning( $warning ) {
 423                 global $wgOut, $wgUser, $wgLang, $wgUploadDirectory, $wgRequest;
 424                 global $wgUseCopyrightUpload;
 425
 426                 $this->mSessionKey = $this->stashSession();
 427                 if( !$this->mSessionKey ) {
 428                         # Couldn't save file; an error has been displayed so let's go.
 429                         return;
 430                 }
 431
 432                 $sub = wfMsg( 'uploadwarning' );
 433                 $wgOut->addHTML( "<h2>{$sub}</h2>\n" );
 434                 $wgOut->addHTML( "<ul class='warning'>{$warning}</ul><br/>\n" );
 435
 436                 $save = wfMsg( 'savefile' );
 437                 $reupload = wfMsg( 'reupload' );
 438                 $iw = wfMsg( 'ignorewarning' );
 439                 $reup = wfMsg( 'reuploaddesc' );
 440                 $titleObj = Title::makeTitle( NS_SPECIAL, 'Upload' );
 441                 $action = $titleObj->escapeLocalURL( 'action=submit' );
 442
 443                 if ( $wgUseCopyrightUpload )
 444                 {
 445                         $copyright =  "
 446         <input type='hidden' name=\"wpUploadCopyStatus\" value=\"" . htmlspecialchars( $this->mUploadCopyStatus ) . "\" />
 447         <input type='hidden' name=\"wpUploadSource\" value=\"" . htmlspecialchars( $this->mUploadSource ) . "\" />
 448         ";
 449                 } else {
 450                         $copyright = "";
 451                 }
 452
 453                 $wgOut->addHTML( "
 454         <form id=\"uploadwarning\" method=\"post\" enctype=\"multipart/form-data\"
 455         action=\"{$action}\">
 456         <input type=hidden name=\"wpUploadAffirm\" value=\"1\" />
 457         <input type=hidden name=\"wpIgnoreWarning\" value=\"1\" />
 458         <input type=hidden name=\"wpSessionKey\" value=\"" . htmlspecialchars( $this->mSessionKey ) . "\" />
 459         <input type=hidden name=\"wpUploadDescription\" value=\"" . htmlspecialchars( $this->mUploadDescription ) . "\" />
 460         {$copyright}
 461         <table border='0'><tr>
 462         <tr><td align='right'>
 463         <input tabindex='2' type='submit' name=\"wpUpload\" value=\"{$save}\" />
 464         </td><td align='left'>{$iw}</td></tr>
 465         <tr><td align='right'>
 466         <input tabindex='2' type='submit' name=\"wpReUpload\" value=\"{$reupload}\" />
 467         </td><td align='left'>{$reup}</td></tr></table></form>\n" );
 468         }
 469
 470         /**
 471          * Displays the main upload form, optionally with a highlighted
 472          * error message up at the top.
 473          *
 474          * @param string $msg as HTML
 475          * @access private
 476          */
 477         function mainUploadForm( $msg='' ) {
 478                 global $wgOut, $wgUser, $wgLang, $wgUploadDirectory, $wgRequest;
 479                 global $wgUseCopyrightUpload;
 480
 481                 if ( '' != $msg ) {
 482                         $sub = wfMsg( 'uploaderror' );
 483                         $wgOut->addHTML( "<h2>{$sub}</h2>\n" .
 484                           "<h4 class='error'>{$msg}</h4>\n" );
 485                 } else {
 486                         $sub = wfMsg( 'uploadfile' );
 487                         $wgOut->addHTML( "<h2>{$sub}</h2>\n" );
 488                 }
 489                 $wgOut->addWikiText( wfMsg( 'uploadtext' ) );
 490                 $sk = $wgUser->getSkin();
 491
 492                 $fn = wfMsg( 'filename' );
 493                 $fd = wfMsg( 'filedesc' );
 494                 $ulb = wfMsg( 'uploadbtn' );
 495
 496                 $clink = $sk->makeKnownLink( wfMsgForContent( 'copyrightpage' ),
 497                   wfMsg( 'copyrightpagename' ) );
 498                 $ca = wfMsg( 'affirmation', $clink );
 499                 $iw = wfMsg( 'ignorewarning' );
 500
 501                 $titleObj = Title::makeTitle( NS_SPECIAL, 'Upload' );
 502                 $action = $titleObj->escapeLocalURL();
 503
 504                 $source = "
 505         <td align='right'>
 506         <input tabindex='3' type='checkbox' name=\"wpUploadAffirm\" value=\"1\" id=\"wpUploadAffirm\" />
 507         </td><td align='left'><label for=\"wpUploadAffirm\">{$ca}</label></td>
 508         " ;
 509                 if ( $wgUseCopyrightUpload )
 510                   {
 511                         $source = "
 512         <td align='right' nowrap='nowrap'>" . wfMsg ( 'filestatus' ) . ":</td>
 513         <td><input tabindex='3' type='text' name=\"wpUploadCopyStatus\" value=\"" .
 514         htmlspecialchars($this->mUploadCopyStatus). "\" size='40' /></td>
 515         </tr><tr>
 516         <td align='right'>". wfMsg ( 'filesource' ) . ":</td>
 517         <td><input tabindex='4' type='text' name=\"wpUploadSource\" value=\"" .
 518         htmlspecialchars($this->mUploadSource). "\" size='40' /></td>
 519         " ;
 520                   }
 521
 522                 $wgOut->addHTML( "
 523         <form id=\"upload\" method=\"post\" enctype=\"multipart/form-data\"
 524         action=\"{$action}\">
 525         <table border='0'><tr>
 526         <td align='right'>{$fn}:</td><td align='left'>
 527         <input tabindex='1' type='file' name=\"wpUploadFile\" size='40' />
 528         </td></tr><tr>
 529         <td align='right'>{$fd}:</td><td align='left'>
 530         <input tabindex='2' type='text' name=\"wpUploadDescription\" value=\""
 531           . htmlspecialchars( $this->mUploadDescription ) . "\" size='40' />
 532         </td></tr><tr>
 533         {$source}
 534         </tr>
 535         <tr><td></td><td align='left'>
 536         <input tabindex='5' type='submit' name=\"wpUpload\" value=\"{$ulb}\" />
 537         </td></tr></table></form>\n" );
 538         }
 539
 540         /* -------------------------------------------------------------- */
 541
 542         /**
 543          * Split a file into a base name and all dot-delimited 'extensions'
 544          * on the end. Some web server configurations will fall back to
 545          * earlier pseudo-'extensions' to determine type and execute
 546          * scripts, so the blacklist needs to check them all.
 547          *
 548          * @return array
 549          */
 550         function splitExtensions( $filename ) {
 551                 $bits = explode( '.', $filename );
 552                 $basename = array_shift( $bits );
 553                 return array( $basename, $bits );
 554         }
 555
 556         /**
 557          * Perform case-insensitive match against a list of file extensions.
 558          * Returns true if the extension is in the list.
 559          *
 560          * @param string $ext
 561          * @param array $list
 562          * @return bool
 563          */
 564         function checkFileExtension( $ext, $list ) {
 565                 return in_array( strtolower( $ext ), $list );
 566         }
 567
 568         /**
 569          * Perform case-insensitive match against a list of file extensions.
 570          * Returns true if any of the extensions are in the list.
 571          *
 572          * @param array $ext
 573          * @param array $list
 574          * @return bool
 575          */
 576         function checkFileExtensionList( $ext, $list ) {
 577                 foreach( $ext as $e ) {
 578                         if( in_array( strtolower( $e ), $list ) ) {
 579                                 return true;
 580                         }
 581                 }
 582                 return false;
 583         }
 584
 585         /**
 586          * Returns false if the file is of a known type but can't be recognized,
 587          * indicating a corrupt file.
 588          * Returns true otherwise; unknown file types are not checked if given
 589          * with an unrecognized extension.
 590          *
 591          * @param string $tmpfile Pathname to the temporary upload file
 592          * @param string $extension The filename extension that the file is to be served with
 593          * @return bool
 594          */
 595         function verify( $tmpfile, $extension ) {
 596                 if( $this->triggersIEbug( $tmpfile ) ) {
 597                         return false;
 598                 }
 599
 600                 $fname = 'SpecialUpload::verify';
 601                 $mergeExtensions = array(
 602                         'jpg' => 'jpeg',
 603                         'tif' => 'tiff' );
 604                 $extensionTypes = array(
 605                         # See http://www.php.net/getimagesize
 606                         1 => 'gif',
 607                         2 => 'jpeg',
 608                         3 => 'png',
 609                         4 => 'swf',
 610                         5 => 'psd',
 611                         6 => 'bmp',
 612                         7 => 'tiff',
 613                         8 => 'tiff',
 614                         9 => 'jpc',
 615                         10 => 'jp2',
 616                         11 => 'jpx',
 617                         12 => 'jb2',
 618                         13 => 'swc',
 619                         14 => 'iff',
 620                         15 => 'wbmp',
 621                         16 => 'xbm' );
 622
 623                 $extension = strtolower( $extension );
 624                 if( isset( $mergeExtensions[$extension] ) ) {
 625                         $extension = $mergeExtensions[$extension];
 626                 }
 627                 wfDebug( "$fname: Testing file '$tmpfile' with given extension '$extension'\n" );
 628
 629                 if( !in_array( $extension, $extensionTypes ) ) {
 630                         # Not a recognized image type. We don't know how to verify these.
 631                         # They're allowed by policy or they wouldn't get this far, so we'll
 632                         # let them slide for now.
 633                         wfDebug( "$fname: Unknown extension; passing.\n" );
 634                         return true;
 635                 }
 636
 637                 $data = @getimagesize( $tmpfile );
 638                 if( false === $data ) {
 639                         # Didn't recognize the image type.
 640                         # Either the image is corrupt or someone's slipping us some
 641                         # bogus data such as HTML+JavaScript trying to take advantage
 642                         # of an Internet Explorer security flaw.
 643                         wfDebug( "$fname: getimagesize() doesn't recognize the file; rejecting.\n" );
 644                         return false;
 645                 }
 646
 647                 $imageType = $data[2];
 648                 if( !isset( $extensionTypes[$imageType] ) ) {
 649                         # Now we're kind of confused. Perhaps new image types added
 650                         # to PHP's support that we don't know about.
 651                         # We'll let these slide for now.
 652                         wfDebug( "$fname: getimagesize() knows the file, but we don't recognize the type; passing.\n" );
 653                         return true;
 654                 }
 655
 656                 $ext = strtolower( $extension );
 657                 if( $extension != $extensionTypes[$imageType] ) {
 658                         # The given filename extension doesn't match the
 659                         # file type. Probably just a mistake, but it's a stupid
 660                         # one and we shouldn't let it pass. KILL THEM!
 661                         wfDebug( "$fname: file extension does not match recognized type; rejecting.\n" );
 662                         return false;
 663                 }
 664
 665                 wfDebug( "$fname: all clear; passing.\n" );
 666                 return true;
 667         }
 668
 669         /**
 670          * Internet Explorer for Windows performs some really stupid file type
 671          * autodetection which can cause it to interpret valid image files as HTML
 672          * and potentially execute JavaScript, creating a cross-site scripting
 673          * attack vectors.
 674          *
 675          * Returns true if IE is likely to mistake the given file for HTML.
 676          *
 677          * @param string $filename
 678          * @return bool
 679          */
 680         function triggersIEbug( $filename ) {
 681                 $file = fopen( $filename, 'rb' );
 682                 $chunk = strtolower( fread( $file, 200 ) );
 683                 fclose( $file );
 684
 685                 $tags = array( '<html', '<head', '<body', '<script' );
 686                 foreach( $tags as $tag ) {
 687                         if( false !== strpos( $chunk, $tag ) ) {
 688                                 return true;
 689                         }
 690                 }
 691                 return false;
 692         }
 693 }
 694 ?>