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<?php |
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/** |
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* Adds an additional validation rule to Upload_Validator that attempts to detect |
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* the file extension of an uploaded file matches it's contents, which is done |
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* by detecting the MIME type and doing a fuzzy match. |
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*/ |
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class MimeUploadValidator extends Upload_Validator |
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{ |
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/** |
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* The preg_replace() pattern to use against MIME types. Used to strip out |
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* useless characters so matching of MIME types can be fuzzy. |
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* |
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* @var string Regexp pattern |
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*/ |
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protected $filterPattern = '/.*[\/\.\-\+]/i'; |
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public function setFilterPattern($pattern) |
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{ |
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$this->filterPattern = $pattern; |
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} |
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public function getFilterPattern() |
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{ |
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return $this->filterPattern; |
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} |
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/** |
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* Check if the temporary file has a valid MIME type for it's extension. |
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* |
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* @uses finfo php extension |
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* @return boolean|null |
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*/ |
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public function isValidMime() |
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{ |
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$extension = strtolower(pathinfo($this->tmpFile['name'], PATHINFO_EXTENSION)); |
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// we can't check filenames without an extension or no temp file path, let them pass validation. |
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if (!$extension || !$this->tmpFile['tmp_name']) { |
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return true; |
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} |
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$expectedMimes = $this->getExpectedMimeTypes($this->tmpFile); |
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if (empty($expectedMimes)) { |
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throw new MimeUploadValidator_Exception( |
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sprintf('Could not find a MIME type for extension %s', $extension) |
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); |
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} |
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$finfo = new finfo(FILEINFO_MIME_TYPE); |
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$foundMime = $finfo->file($this->tmpFile['tmp_name']); |
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if (!$foundMime) { |
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throw new MimeUploadValidator_Exception( |
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sprintf('Could not find a MIME type for file %s', $this->tmpFile['tmp_name']) |
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); |
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} |
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foreach ($expectedMimes as $expected) { |
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if ($this->compareMime($foundMime, $expected)) { |
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return true; |
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} |
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} |
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return false; |
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} |
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/** |
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* Fetches an array of valid mimetypes. |
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* |
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* @return array |
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*/ |
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public function getExpectedMimeTypes($tmpFile) |
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{ |
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$extension = strtolower(pathinfo($tmpFile['name'], PATHINFO_EXTENSION)); |
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// if the finfo php extension isn't loaded, we can't complete this check. |
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if (!class_exists('finfo')) { |
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throw new MimeUploadValidator_Exception('PHP extension finfo is not loaded'); |
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} |
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// Attempt to figure out which mime types are expected/acceptable here. |
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$expectedMimes = array(); |
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// Get the mime types set in framework core |
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$knownMimes = Config::inst()->get('HTTP', 'MimeTypes'); |
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if (isset($knownMimes[$extension])) { |
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$expectedMimes[] = $knownMimes[$extension]; |
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} |
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// Get the mime types and their variations from mimevalidator |
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$knownMimes = Config::inst()->get(get_class($this), 'MimeTypes'); |
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if (isset($knownMimes[$extension])) { |
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if (is_array($knownMimes[$extension])) { |
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$expectedMimes += $knownMimes[$extension]; |
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} else { |
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$expectedMimes[] = $knownMimes[$extension]; |
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} |
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} |
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return $expectedMimes; |
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} |
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/** |
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* Check two MIME types roughly match eachother. |
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* |
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* Before we check MIME types, remove known prefixes "vnd.", "x-" etc. |
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* If there is a suffix, we'll use that to compare. Examples: |
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* |
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* application/x-json = json |
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* application/json = json |
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* application/xhtml+xml = xml |
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* application/xml = xml |
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* |
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* @param string $first The first MIME type to compare to the second |
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* @param string $second The second MIME type to compare to the first |
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* @return boolean |
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*/ |
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public function compareMime($first, $second) |
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{ |
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return preg_replace($this->filterPattern, '', $first) === preg_replace($this->filterPattern, '', $second); |
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} |
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public function validate() |
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{ |
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if (parent::validate() === false) { |
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return false; |
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} |
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try { |
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$result = $this->isValidMime(); |
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if ($result === false) { |
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$this->errors[] = _t( |
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'File.INVALIDMIME', |
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'File extension does not match known MIME type' |
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); |
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return false; |
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} |
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} catch (MimeUploadValidator_Exception $e) { |
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$this->errors[] = _t( |
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'File.FAILEDMIMECHECK', |
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'MIME validation failed: {message}', |
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'Argument 1: Message about why MIME type detection failed', |
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array('message' => $e->getMessage()) |
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); |
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return false; |
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} |
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return true; |
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} |
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} |
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class MimeUploadValidator_Exception extends Exception |
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{ |
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} |
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You can fix this by adding a namespace to your class:
When choosing a vendor namespace, try to pick something that is not too generic to avoid conflicts with other libraries.