Standard implementation of the filename sanitizing interface. More...

Inheritance diagram for ILIAS\Filesystem\Security\Sanitizing\DefaultFilenameSanitizer:

Collaboration diagram for ILIAS\Filesystem\Security\Sanitizing\DefaultFilenameSanitizer:

Public Member Functions
	__construct (private FilesystemConfig $settings)

	isClean (string $filename)
	Checks if the filename is prefixed with a valid whitelisted ending. More...

	sanitize (string $filename)
	@inheritDoc More...

	isClean (string $filename)
	Checks if the filename is prefixed with a valid whitelisted ending. More...

	sanitize (string $filename)
	Validates the file ending, with the filesystem whitelist provided by ILIAS. More...

Private Member Functions
	getWhitelistedSuffixes ()

	extractFileSuffix (string $filename)
	Extracts the suffix from the given filename. More...

Private Attributes
array	$whitelist = null

Additional Inherited Members
Data Fields inherited from ILIAS\Filesystem\Security\Sanitizing\FilenameSanitizer
const	CLEAN_FILE_SUFFIX = 'sec'
	This file suffix will be used to sanitize not whitelisted file names. More...

Detailed Description

Standard implementation of the filename sanitizing interface.

Author: Nicolas Schäfli ns@st.nosp@m.uder.nosp@m.-raim.nosp@m.ann..nosp@m.ch; Fabian Schmid fabia.nosp@m.n@sr.nosp@m..solu.nosp@m.tion.nosp@m.s

Definition at line 32 of file DefaultFilenameSanitizer.php.

Constructor & Destructor Documentation

◆ __construct()

ILIAS\Filesystem\Security\Sanitizing\DefaultFilenameSanitizer::__construct ( private FilesystemConfig $settings )

Definition at line 36 of file DefaultFilenameSanitizer.php.

      {
 
    }

Member Function Documentation

◆ extractFileSuffix()

ILIAS\Filesystem\Security\Sanitizing\DefaultFilenameSanitizer::extractFileSuffix ( string $filename )

private

Extracts the suffix from the given filename.

If no suffix was found an empty string will be returned.

Parameters

string $filename The filename which should be used to extract the file suffix.

Returns: string The file name suffix in lowercase.

Definition at line 123 of file DefaultFilenameSanitizer.php.

                                                        : string
    {
        return strtolower(pathinfo($filename, PATHINFO_EXTENSION));
    }

References $filename.

Referenced by ILIAS\Filesystem\Security\Sanitizing\DefaultFilenameSanitizer\isClean().

Here is the caller graph for this function:

◆ getWhitelistedSuffixes()

ILIAS\Filesystem\Security\Sanitizing\DefaultFilenameSanitizer::getWhitelistedSuffixes ( )

private

Definition at line 42 of file DefaultFilenameSanitizer.php.

                                             : array
    {
        if ($this->whitelist !== null) {
            return $this->whitelist;
        }
 
        $this->whitelist = array_diff($this->settings->getWhiteListedSuffixes(), $this->settings->getBlackListedSuffixes());
 
        // the negative list does not apply to users holding the bypass permission, the
        // same rule FileServicesPolicy::isBlockedExtension() follows. Only suffixes the
        // negative list removed from the default or the positive list come back; the
        // prohibited suffixes and the hard coded protection against php suffixes stay
        // in effect, see https://mantis.ilias.de/view.php?id=47828
        if ($this->settings->isByPassAllowedForCurrentUser()) {
            $removed_by_negative_list = array_intersect(
                $this->settings->getWhiteListNegative(),
                array_merge($this->settings->getDefaultWhitelist(), $this->settings->getWhiteListPositive())
            );
            $this->whitelist = array_merge(
                $this->whitelist,
                array_diff($removed_by_negative_list, $this->settings->getProhibited())
            );
        }
 
        // the secure file ending must be valid, therefore add it if it got removed from the white list.
        if (!in_array(FilenameSanitizer::CLEAN_FILE_SUFFIX, $this->whitelist, true)) {
            $this->whitelist[] = FilenameSanitizer::CLEAN_FILE_SUFFIX;
        }
        return $this->whitelist;
    }

References ILIAS\Filesystem\Security\Sanitizing\DefaultFilenameSanitizer\$whitelist, ILIAS\Filesystem\Security\Sanitizing\FilenameSanitizer\CLEAN_FILE_SUFFIX, and ILIAS\Repository\settings().

Referenced by ILIAS\Filesystem\Security\Sanitizing\DefaultFilenameSanitizer\isClean().

Here is the call graph for this function:

Here is the caller graph for this function:

◆ isClean()

ILIAS\Filesystem\Security\Sanitizing\DefaultFilenameSanitizer::isClean ( string $filename )

Checks if the filename is prefixed with a valid whitelisted ending.

Parameters

string $filename The filename which should be checked for a whitelisted ending.

Returns: bool True if the filename ending is whitelisted otherwise false.

Implements ILIAS\Filesystem\Security\Sanitizing\FilenameSanitizer.

Definition at line 74 of file DefaultFilenameSanitizer.php.

                                             : bool
    {
        // check the raw and the percent-decoded spelling; both must be acceptable
        foreach ([$filename, rawurldecode($filename)] as $candidate) {
            $suffix = $this->extractFileSuffix($candidate);
            if (preg_match('/^ph(p[3457]?|t|tml|ar)$/i', $suffix)) {
                return false;
            }
            if (!in_array($suffix, $this->getWhitelistedSuffixes(), true)) {
                return false;
            }
        }
 
        return true;
    }

References $filename, ILIAS\Filesystem\Security\Sanitizing\DefaultFilenameSanitizer\extractFileSuffix(), and ILIAS\Filesystem\Security\Sanitizing\DefaultFilenameSanitizer\getWhitelistedSuffixes().

Referenced by ILIAS\Filesystem\Security\Sanitizing\DefaultFilenameSanitizer\sanitize().

Here is the call graph for this function:

Here is the caller graph for this function:

◆ sanitize()

ILIAS\Filesystem\Security\Sanitizing\DefaultFilenameSanitizer::sanitize ( string $filename )

@inheritDoc

Implements ILIAS\Filesystem\Security\Sanitizing\FilenameSanitizer.

Definition at line 93 of file DefaultFilenameSanitizer.php.

                                              : string
    {
        $filename = Util::sanitizeFileName($filename);
 
        if ($this->isClean($filename)) {
            return $filename;
        }
 
        $pathInfo = pathinfo($filename);
        $basename = $pathInfo['basename'];
        $parentPath = $pathInfo['dirname'] === '.' ? '' : $pathInfo['dirname'];
 
        $filename = str_replace('.', '', $basename);
        $filename .= "." . FilenameSanitizer::CLEAN_FILE_SUFFIX;
 
        // there is no parent
        if ($parentPath === '') {
            return $filename;
        }
 
        return "$parentPath/$filename";
    }