+
+ /* -------------------------------------------------------------- */
+
+ /**
+ * Split a file into a base name and all dot-delimited 'extensions'
+ * on the end. Some web server configurations will fall back to
+ * earlier pseudo-'extensions' to determine type and execute
+ * scripts, so the blacklist needs to check them all.
+ *
+ * @return array
+ */
+ function splitExtensions( $filename ) {
+ $bits = explode( '.', $filename );
+ $basename = array_shift( $bits );
+ return array( $basename, $bits );
+ }
+
+ /**
+ * Perform case-insensitive match against a list of file extensions.
+ * Returns true if the extension is in the list.
+ *
+ * @param string $ext
+ * @param array $list
+ * @return bool
+ */
+ function checkFileExtension( $ext, $list ) {
+ return in_array( strtolower( $ext ), $list );
+ }
+
+ /**
+ * Perform case-insensitive match against a list of file extensions.
+ * Returns true if any of the extensions are in the list.
+ *
+ * @param array $ext
+ * @param array $list
+ * @return bool
+ */
+ function checkFileExtensionList( $ext, $list ) {
+ foreach( $ext as $e ) {
+ if( in_array( strtolower( $e ), $list ) ) {
+ return true;
+ }
+ }
+ return false;
+ }
+
+ /**
+ * Verifies that it's ok to include the uploaded file
+ *
+ * @param string $tmpfile the full path of the temporary file to verify
+ * @param string $extension The filename extension that the file is to be served with
+ * @return mixed true of the file is verified, a WikiError object otherwise.
+ */
+ function verify( $tmpfile, $extension ) {
+ #magically determine mime type
+ $magic=& wfGetMimeMagic();
+ $mime= $magic->guessMimeType($tmpfile,false);
+
+ $fname= "SpecialUpload::verify";
+
+ #check mime type, if desired
+ global $wgVerifyMimeType;
+ if ($wgVerifyMimeType) {
+
+ #check mime type against file extension
+ if( !$this->verifyExtension( $mime, $extension ) ) {
+ return new WikiErrorMsg( 'uploadcorrupt' );
+ }
+
+ #check mime type blacklist
+ global $wgMimeTypeBlacklist;
+ if( isset($wgMimeTypeBlacklist) && !is_null($wgMimeTypeBlacklist)
+ && $this->checkFileExtension( $mime, $wgMimeTypeBlacklist ) ) {
+ return new WikiErrorMsg( 'badfiletype', htmlspecialchars( $mime ) );
+ }
+ }
+
+ #check for htmlish code and javascript
+ if( $this->detectScript ( $tmpfile, $mime ) ) {
+ return new WikiErrorMsg( 'uploadscripted' );
+ }
+
+ /**
+ * Scan the uploaded file for viruses
+ */
+ $virus= $this->detectVirus($tmpfile);
+ if ( $virus ) {
+ return new WikiErrorMsg( 'uploadvirus', htmlspecialchars($virus) );
+ }
+
+ wfDebug( "$fname: all clear; passing.\n" );
+ return true;
+ }
+
+ /**
+ * Checks if the mime type of the uploaded file matches the file extension.
+ *
+ * @param string $mime the mime type of the uploaded file
+ * @param string $extension The filename extension that the file is to be served with
+ * @return bool
+ */
+ function verifyExtension( $mime, $extension ) {
+ $fname = 'SpecialUpload::verifyExtension';
+
+ $magic =& wfGetMimeMagic();
+
+ if ( ! $mime || $mime == 'unknown' || $mime == 'unknown/unknown' )
+ if ( ! $magic->isRecognizableExtension( $extension ) ) {
+ wfDebug( "$fname: passing file with unknown detected mime type; unrecognized extension '$extension', can't verify\n" );
+ return true;
+ } else {
+ wfDebug( "$fname: rejecting file with unknown detected mime type; recognized extension '$extension', so probably invalid file\n" );
+ return false;
+ }
+
+ $match= $magic->isMatchingExtension($extension,$mime);
+
+ if ($match===NULL) {
+ wfDebug( "$fname: no file extension known for mime type $mime, passing file\n" );
+ return true;
+ } elseif ($match===true) {
+ wfDebug( "$fname: mime type $mime matches extension $extension, passing file\n" );
+
+ #TODO: if it's a bitmap, make sure PHP or ImageMagic resp. can handle it!
+ return true;
+
+ } else {
+ wfDebug( "$fname: mime type $mime mismatches file extension $extension, rejecting file\n" );
+ return false;
+ }
+ }
+
+ /** Heuristig for detecting files that *could* contain JavaScript instructions or
+ * things that may look like HTML to a browser and are thus
+ * potentially harmful. The present implementation will produce false positives in some situations.
+ *
+ * @param string $file Pathname to the temporary upload file
+ * @param string $mime The mime type of the file
+ * @return bool true if the file contains something looking like embedded scripts
+ */
+ function detectScript($file,$mime) {
+
+ #ugly hack: for text files, always look at the entire file.
+ #For binarie field, just check the first K.
+
+ if (strpos($mime,'text/')===0) $chunk = file_get_contents( $file );
+ else {
+ $fp = fopen( $file, 'rb' );
+ $chunk = fread( $fp, 1024 );
+ fclose( $fp );
+ }
+
+ $chunk= strtolower( $chunk );
+
+ if (!$chunk) return false;
+
+ #decode from UTF-16 if needed (could be used for obfuscation).
+ if (substr($chunk,0,2)=="\xfe\xff") $enc= "UTF-16BE";
+ elseif (substr($chunk,0,2)=="\xff\xfe") $enc= "UTF-16LE";
+ else $enc= NULL;
+
+ if ($enc) $chunk= iconv($enc,"ASCII//IGNORE",$chunk);
+
+ $chunk= trim($chunk);
+
+ #FIXME: convert from UTF-16 if necessarry!
+
+ wfDebug("SpecialUpload::detectScript: checking for embedded scripts and HTML stuff\n");
+
+ #check for HTML doctype
+ if (eregi("<!DOCTYPE *X?HTML",$chunk)) return true;
+
+ /**
+ * Internet Explorer for Windows performs some really stupid file type
+ * autodetection which can cause it to interpret valid image files as HTML
+ * and potentially execute JavaScript, creating a cross-site scripting
+ * attack vectors.
+ *
+ * Apple's Safari browser also performs some unsafe file type autodetection
+ * which can cause legitimate files to be interpreted as HTML if the
+ * web server is not correctly configured to send the right content-type
+ * (or if you're really uploading plain text and octet streams!)
+ *
+ * Returns true if IE is likely to mistake the given file for HTML.
+ * Also returns true if Safari would mistake the given file for HTML
+ * when served with a generic content-type.
+ */
+
+ $tags = array(
+ '<body',
+ '<head',
+ '<html', #also in safari
+ '<img',
+ '<pre',
+ '<script', #also in safari
+ '<table',
+ '<title' #also in safari
+ );
+
+ foreach( $tags as $tag ) {
+ if( false !== strpos( $chunk, $tag ) ) {
+ return true;
+ }
+ }
+
+ /*
+ * look for javascript
+ */
+
+ #resolve entity-refs to look at attributes. may be harsh on big files... cache result?
+ $chunk = Sanitizer::decodeCharReferences( $chunk );
+
+ #look for script-types
+ if (preg_match("!type\s*=\s*['\"]?\s*(\w*/)?(ecma|java)!sim",$chunk)) return true;
+
+ #look for html-style script-urls
+ if (preg_match("!(href|src|data)\s*=\s*['\"]?\s*(ecma|java)script:!sim",$chunk)) return true;
+
+ #look for css-style script-urls
+ if (preg_match("!url\s*\(\s*['\"]?\s*(ecma|java)script:!sim",$chunk)) return true;
+
+ wfDebug("SpecialUpload::detectScript: no scripts found\n");
+ return false;
+ }
+
+ /** Generic wrapper function for a virus scanner program.
+ * This relies on the $wgAntivirus and $wgAntivirusSetup variables.
+ * $wgAntivirusRequired may be used to deny upload if the scan fails.
+ *
+ * @param string $file Pathname to the temporary upload file
+ * @return mixed false if not virus is found, NULL if the scan fails or is disabled,
+ * or a string containing feedback from the virus scanner if a virus was found.
+ * If textual feedback is missing but a virus was found, this function returns true.
+ */
+ function detectVirus($file) {
+ global $wgAntivirus, $wgAntivirusSetup, $wgAntivirusRequired;
+
+ $fname= "SpecialUpload::detectVirus";
+
+ if (!$wgAntivirus) { #disabled?
+ wfDebug("$fname: virus scanner disabled\n");
+
+ return NULL;
+ }
+
+ if (!$wgAntivirusSetup[$wgAntivirus]) {
+ wfDebug("$fname: unknown virus scanner: $wgAntivirus\n");
+
+ $wgOut->addHTML( "<div class='error'>Bad configuration: unknown virus scanner: <i>$wgAntivirus</i></div>\n" ); #LOCALIZE
+
+ return "unknown antivirus: $wgAntivirus";
+ }
+
+ #look up scanner configuration
+ $virus_scanner= $wgAntivirusSetup[$wgAntivirus]["command"]; #command pattern
+ $virus_scanner_codes= $wgAntivirusSetup[$wgAntivirus]["codemap"]; #exit-code map
+ $msg_pattern= $wgAntivirusSetup[$wgAntivirus]["messagepattern"]; #message pattern
+
+ $scanner= $virus_scanner; #copy, so we can resolve the pattern
+
+ if (strpos($scanner,"%f")===false) $scanner.= " ".wfEscapeShellArg($file); #simple pattern: append file to scan
+ else $scanner= str_replace("%f",wfEscapeShellArg($file),$scanner); #complex pattern: replace "%f" with file to scan
+
+ wfDebug("$fname: running virus scan: $scanner \n");
+
+ #execute virus scanner
+ $code= false;
+
+ #NOTE: there's a 50 line workaround to make stderr redirection work on windows, too.
+ # that does not seem to be worth the pain.
+ # Ask me (Duesentrieb) about it if it's ever needed.
+ if (wfIsWindows()) exec("$scanner",$output,$code);
+ else exec("$scanner 2>&1",$output,$code);
+
+ $exit_code= $code; #remeber for user feedback
+
+ if ($virus_scanner_codes) { #map exit code to AV_xxx constants.
+ if (isset($virus_scanner_codes[$code])) $code= $virus_scanner_codes[$code]; #explicite mapping
+ else if (isset($virus_scanner_codes["*"])) $code= $virus_scanner_codes["*"]; #fallback mapping
+ }
+
+ if ($code===AV_SCAN_FAILED) { #scan failed (code was mapped to false by $virus_scanner_codes)
+ wfDebug("$fname: failed to scan $file (code $exit_code).\n");
+
+ if ($wgAntivirusRequired) return "scan failed (code $exit_code)";
+ else return NULL;
+ }
+ else if ($code===AV_SCAN_ABORTED) { #scan failed because filetype is unknown (probably imune)
+ wfDebug("$fname: unsupported file type $file (code $exit_code).\n");
+ return NULL;
+ }
+ else if ($code===AV_NO_VIRUS) {
+ wfDebug("$fname: file passed virus scan.\n");
+ return false; #no virus found
+ }
+ else {
+ $output= join("\n",$output);
+ $output= trim($output);
+
+ if (!$output) $output= true; #if ther's no output, return true
+ else if ($msg_pattern) {
+ $groups= array();
+ if (preg_match($msg_pattern,$output,$groups)) {
+ if ($groups[1]) $output= $groups[1];
+ }
+ }
+
+ wfDebug("$fname: FOUND VIRUS! scanner feedback: $output");
+ return $output;
+ }
+ }
+
+ /**
+ * Check if the temporary file is MacBinary-encoded, as some uploads
+ * from Internet Explorer on Mac OS Classic and Mac OS X will be.
+ * If so, the data fork will be extracted to a second temporary file,
+ * which will then be checked for validity and either kept or discarded.
+ *
+ * @access private
+ */
+ function checkMacBinary() {
+ $macbin = new MacBinary( $this->mUploadTempName );
+ if( $macbin->isValid() ) {
+ $dataFile = tempnam( wfTempDir(), "WikiMacBinary" );
+ $dataHandle = fopen( $dataFile, 'wb' );
+
+ wfDebug( "SpecialUpload::checkMacBinary: Extracting MacBinary data fork to $dataFile\n" );
+ $macbin->extractData( $dataHandle );
+
+ $this->mUploadTempName = $dataFile;
+ $this->mUploadSize = $macbin->dataForkLength();
+
+ // We'll have to manually remove the new file if it's not kept.
+ $this->mRemoveTempFile = true;
+ }
+ $macbin->close();
+ }
+
+ /**
+ * If we've modified the upload file we need to manually remove it
+ * on exit to clean up.
+ * @access private
+ */
+ function cleanupTempFile() {
+ if( $this->mRemoveTempFile && file_exists( $this->mUploadTempName ) ) {
+ wfDebug( "SpecialUpload::cleanupTempFile: Removing temporary file $this->mUploadTempName\n" );
+ unlink( $this->mUploadTempName );
+ }
+ }
+
+ /**
+ * Check if there's an overwrite conflict and, if so, if restrictions
+ * forbid this user from performing the upload.
+ *
+ * @return mixed true on success, WikiError on failure
+ * @access private
+ */
+ function checkOverwrite( $name ) {
+ $img = Image::newFromName( $name );
+ if( is_null( $img ) ) {
+ // Uh... this shouldn't happen ;)
+ // But if it does, fall through to previous behavior
+ return false;
+ }
+
+ $error = '';
+ if( $img->exists() ) {
+ global $wgUser, $wgOut;
+ if( $img->isLocal() ) {
+ if( !$wgUser->isAllowed( 'reupload' ) ) {
+ $error = 'fileexists-forbidden';
+ }
+ } else {
+ if( !$wgUser->isAllowed( 'reupload' ) ||
+ !$wgUser->isAllowed( 'reupload-shared' ) ) {
+ $error = "fileexists-shared-forbidden";
+ }
+ }
+ }
+
+ if( $error ) {
+ $errorText = wfMsg( $error, wfEscapeWikiText( $img->getName() ) );
+ return new WikiError( $wgOut->parse( $errorText ) );
+ }
+
+ // Rockin', go ahead and upload
+ return true;
+ }
+