496 lines
13 KiB
PHP
496 lines
13 KiB
PHP
<?php
|
|
/**
|
|
* ownCloud
|
|
*
|
|
* @author Robin Appelman
|
|
* @copyright 2012 Sam Tuke <samtuke@owncloud.com>, 2011 Robin Appelman
|
|
* <icewind1991@gmail.com>
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
|
|
* License as published by the Free Software Foundation; either
|
|
* version 3 of the License, or any later version.
|
|
*
|
|
* This library is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU AFFERO GENERAL PUBLIC LICENSE for more details.
|
|
*
|
|
* You should have received a copy of the GNU Affero General Public
|
|
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
*/
|
|
|
|
/**
|
|
* transparently encrypted filestream
|
|
*
|
|
* you can use it as wrapper around an existing stream by setting CryptStream::$sourceStreams['foo']=array('path'=>$path,'stream'=>$stream)
|
|
* and then fopen('crypt://streams/foo');
|
|
*/
|
|
|
|
namespace OCA\Encryption;
|
|
|
|
/**
|
|
* @brief Provides 'crypt://' stream wrapper protocol.
|
|
* @note We use a stream wrapper because it is the most secure way to handle
|
|
* decrypted content transfers. There is no safe way to decrypt the entire file
|
|
* somewhere on the server, so we have to encrypt and decrypt blocks on the fly.
|
|
* @note Paths used with this protocol MUST BE RELATIVE. Use URLs like:
|
|
* crypt://filename, or crypt://subdirectory/filename, NOT
|
|
* crypt:///home/user/owncloud/data. Otherwise keyfiles will be put in
|
|
* [owncloud]/data/user/files_encryption/keyfiles/home/user/owncloud/data and
|
|
* will not be accessible to other methods.
|
|
* @note Data read and written must always be 8192 bytes long, as this is the
|
|
* buffer size used internally by PHP. The encryption process makes the input
|
|
* data longer, and input is chunked into smaller pieces in order to result in
|
|
* a 8192 encrypted block size.
|
|
*/
|
|
class Stream {
|
|
|
|
public static $sourceStreams = array();
|
|
|
|
// TODO: make all below properties private again once unit testing is
|
|
// configured correctly
|
|
public $rawPath; // The raw path received by stream_open
|
|
public $path_f; // The raw path formatted to include username and data dir
|
|
private $userId;
|
|
private $handle; // Resource returned by fopen
|
|
private $path;
|
|
private $readBuffer; // For streams that dont support seeking
|
|
private $meta = array(); // Header / meta for source stream
|
|
private $count;
|
|
private $writeCache;
|
|
public $size;
|
|
private $publicKey;
|
|
private $keyfile;
|
|
private $encKeyfile;
|
|
private static $view; // a fsview object set to user dir
|
|
private $rootView; // a fsview object set to '/'
|
|
|
|
public function stream_open( $path, $mode, $options, &$opened_path ) {
|
|
|
|
// Get access to filesystem via filesystemview object
|
|
if ( !self::$view ) {
|
|
|
|
self::$view = new \OC_FilesystemView( $this->userId . '/' );
|
|
|
|
}
|
|
|
|
// Set rootview object if necessary
|
|
if ( ! $this->rootView ) {
|
|
|
|
$this->rootView = new \OC_FilesystemView( $this->userId . '/' );
|
|
|
|
}
|
|
|
|
$this->userId = \OCP\User::getUser();
|
|
|
|
// Get the bare file path
|
|
$path = str_replace( 'crypt://', '', $path );
|
|
|
|
$this->rawPath = $path;
|
|
|
|
$this->path_f = $this->userId . '/files/' . $path;
|
|
|
|
if (
|
|
dirname( $path ) == 'streams'
|
|
and isset( self::$sourceStreams[basename( $path )] )
|
|
) {
|
|
|
|
// Is this just for unit testing purposes?
|
|
|
|
$this->handle = self::$sourceStreams[basename( $path )]['stream'];
|
|
|
|
$this->path = self::$sourceStreams[basename( $path )]['path'];
|
|
|
|
$this->size = self::$sourceStreams[basename( $path )]['size'];
|
|
|
|
} else {
|
|
|
|
if (
|
|
$mode == 'w'
|
|
or $mode == 'w+'
|
|
or $mode == 'wb'
|
|
or $mode == 'wb+'
|
|
) {
|
|
|
|
$this->size = 0;
|
|
|
|
} else {
|
|
|
|
|
|
|
|
$this->size = self::$view->filesize( $this->path_f, $mode );
|
|
|
|
//$this->size = filesize( $path );
|
|
|
|
}
|
|
|
|
// Disable fileproxies so we can open the source file without recursive encryption
|
|
\OC_FileProxy::$enabled = false;
|
|
|
|
//$this->handle = fopen( $path, $mode );
|
|
|
|
$this->handle = self::$view->fopen( $this->path_f, $mode );
|
|
|
|
\OC_FileProxy::$enabled = true;
|
|
|
|
if ( !is_resource( $this->handle ) ) {
|
|
|
|
\OCP\Util::writeLog( 'files_encryption', 'failed to open '.$path, \OCP\Util::ERROR );
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if ( is_resource( $this->handle ) ) {
|
|
|
|
$this->meta = stream_get_meta_data( $this->handle );
|
|
|
|
}
|
|
|
|
return is_resource( $this->handle );
|
|
|
|
}
|
|
|
|
public function stream_seek( $offset, $whence = SEEK_SET ) {
|
|
|
|
$this->flush();
|
|
|
|
fseek( $this->handle, $offset, $whence );
|
|
|
|
}
|
|
|
|
public function stream_tell() {
|
|
return ftell($this->handle);
|
|
}
|
|
|
|
public function stream_read( $count ) {
|
|
|
|
$this->writeCache = '';
|
|
|
|
if ( $count != 8192 ) {
|
|
|
|
// $count will always be 8192 https://bugs.php.net/bug.php?id=21641
|
|
// This makes this function a lot simpler, but will break this class if the above 'bug' gets 'fixed'
|
|
\OCP\Util::writeLog( 'files_encryption', 'PHP "bug" 21641 no longer holds, decryption system requires refactoring', \OCP\Util::FATAL );
|
|
|
|
die();
|
|
|
|
}
|
|
|
|
// $pos = ftell( $this->handle );
|
|
//
|
|
// Get the data from the file handle
|
|
$data = fread( $this->handle, 8192 );
|
|
|
|
if ( strlen( $data ) ) {
|
|
|
|
$this->getKey();
|
|
|
|
$result = Crypt::symmetricDecryptFileContent( $data, $this->keyfile );
|
|
|
|
} else {
|
|
|
|
$result = '';
|
|
|
|
}
|
|
|
|
// $length = $this->size - $pos;
|
|
//
|
|
// if ( $length < 8192 ) {
|
|
//
|
|
// $result = substr( $result, 0, $length );
|
|
//
|
|
// }
|
|
|
|
return $result;
|
|
|
|
}
|
|
|
|
/**
|
|
* @brief Encrypt and pad data ready for writing to disk
|
|
* @param string $plainData data to be encrypted
|
|
* @param string $key key to use for encryption
|
|
* @return encrypted data on success, false on failure
|
|
*/
|
|
public function preWriteEncrypt( $plainData, $key ) {
|
|
|
|
// Encrypt data to 'catfile', which includes IV
|
|
if ( $encrypted = Crypt::symmetricEncryptFileContent( $plainData, $key ) ) {
|
|
|
|
return $encrypted;
|
|
|
|
} else {
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
/**
|
|
* @brief Get the keyfile for the current file, generate one if necessary
|
|
* @param bool $generate if true, a new key will be generated if none can be found
|
|
* @return bool true on key found and set, false on key not found and new key generated and set
|
|
*/
|
|
public function getKey() {
|
|
|
|
// If a keyfile already exists for a file named identically to
|
|
// file to be written
|
|
if ( self::$view->file_exists( $this->userId . '/'. 'files_encryption' . '/' . 'keyfiles' . '/' . $this->rawPath . '.key' ) ) {
|
|
|
|
// TODO: add error handling for when file exists but no
|
|
// keyfile
|
|
|
|
// Fetch existing keyfile
|
|
$this->encKeyfile = Keymanager::getFileKey( $this->rootView, $this->userId, $this->rawPath );
|
|
|
|
$this->getUser();
|
|
|
|
$session = new Session();
|
|
|
|
$privateKey = $session->getPrivateKey( $this->userId );
|
|
|
|
$this->keyfile = Crypt::keyDecrypt( $this->encKeyfile, $privateKey );
|
|
|
|
return true;
|
|
|
|
} else {
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
public function getuser() {
|
|
|
|
// Only get the user again if it isn't already set
|
|
if ( empty( $this->userId ) ) {
|
|
|
|
// TODO: Move this user call out of here - it belongs
|
|
// elsewhere
|
|
$this->userId = \OCP\User::getUser();
|
|
|
|
}
|
|
|
|
// TODO: Add a method for getting the user in case OCP\User::
|
|
// getUser() doesn't work (can that scenario ever occur?)
|
|
|
|
}
|
|
|
|
/**
|
|
* @brief Handle plain data from the stream, and write it in 8192 byte blocks
|
|
* @param string $data data to be written to disk
|
|
* @note the data will be written to the path stored in the stream handle, set in stream_open()
|
|
* @note $data is only ever be a maximum of 8192 bytes long. This is set by PHP internally. stream_write() is called multiple times in a loop on data larger than 8192 bytes
|
|
* @note Because the encryption process used increases the length of $data, a writeCache is used to carry over data which would not fit in the required block size
|
|
* @note Padding is added to each encrypted block to ensure that the resulting block is exactly 8192 bytes. This is removed during stream_read
|
|
* @note PHP automatically updates the file pointer after writing data to reflect it's length. There is generally no need to update the poitner manually using fseek
|
|
*/
|
|
public function stream_write( $data ) {
|
|
|
|
// Disable the file proxies so that encryption is not
|
|
// automatically attempted when the file is written to disk -
|
|
// we are handling that separately here and we don't want to
|
|
// get into an infinite loop
|
|
\OC_FileProxy::$enabled = false;
|
|
|
|
// Get the length of the unencrypted data that we are handling
|
|
$length = strlen( $data );
|
|
|
|
// So far this round, no data has been written
|
|
$written = 0;
|
|
|
|
// Find out where we are up to in the writing of data to the
|
|
// file
|
|
$pointer = ftell( $this->handle );
|
|
|
|
// Make sure the userId is set
|
|
$this->getuser();
|
|
|
|
// TODO: Check if file is shared, if so, use multiKeyEncrypt and
|
|
// save shareKeys in necessary user directories
|
|
|
|
// Get / generate the keyfile for the file we're handling
|
|
// If we're writing a new file (not overwriting an existing
|
|
// one), save the newly generated keyfile
|
|
if ( ! $this->getKey() ) {
|
|
|
|
$this->keyfile = Crypt::generateKey();
|
|
|
|
$this->publicKey = Keymanager::getPublicKey( $this->rootView, $this->userId );
|
|
|
|
$this->encKeyfile = Crypt::keyEncrypt( $this->keyfile, $this->publicKey );
|
|
|
|
$view = new \OC_FilesystemView( '/' );
|
|
$userId = \OCP\User::getUser();
|
|
|
|
// Save the new encrypted file key
|
|
Keymanager::setFileKey( $view, $this->rawPath, $userId, $this->encKeyfile );
|
|
|
|
}
|
|
|
|
// If extra data is left over from the last round, make sure it
|
|
// is integrated into the next 6126 / 8192 block
|
|
if ( $this->writeCache ) {
|
|
|
|
// Concat writeCache to start of $data
|
|
$data = $this->writeCache . $data;
|
|
|
|
// Clear the write cache, ready for resuse - it has been
|
|
// flushed and its old contents processed
|
|
$this->writeCache = '';
|
|
|
|
}
|
|
//
|
|
// // Make sure we always start on a block start
|
|
if ( 0 != ( $pointer % 8192 ) ) {
|
|
// if the current position of
|
|
// file indicator is not aligned to a 8192 byte block, fix it
|
|
// so that it is
|
|
|
|
// fseek( $this->handle, - ( $pointer % 8192 ), SEEK_CUR );
|
|
//
|
|
// $pointer = ftell( $this->handle );
|
|
//
|
|
// $unencryptedNewBlock = fread( $this->handle, 8192 );
|
|
//
|
|
// fseek( $this->handle, - ( $currentPos % 8192 ), SEEK_CUR );
|
|
//
|
|
// $block = Crypt::symmetricDecryptFileContent( $unencryptedNewBlock, $this->keyfile );
|
|
//
|
|
// $x = substr( $block, 0, $currentPos % 8192 );
|
|
//
|
|
// $data = $x . $data;
|
|
//
|
|
// fseek( $this->handle, - ( $currentPos % 8192 ), SEEK_CUR );
|
|
//
|
|
}
|
|
|
|
// $currentPos = ftell( $this->handle );
|
|
|
|
// // While there still remains somed data to be processed & written
|
|
while( strlen( $data ) > 0 ) {
|
|
//
|
|
// // Remaining length for this iteration, not of the
|
|
// // entire file (may be greater than 8192 bytes)
|
|
// $remainingLength = strlen( $data );
|
|
//
|
|
// // If data remaining to be written is less than the
|
|
// // size of 1 6126 byte block
|
|
if ( strlen( $data ) < 6126 ) {
|
|
|
|
// Set writeCache to contents of $data
|
|
// The writeCache will be carried over to the
|
|
// next write round, and added to the start of
|
|
// $data to ensure that written blocks are
|
|
// always the correct length. If there is still
|
|
// data in writeCache after the writing round
|
|
// has finished, then the data will be written
|
|
// to disk by $this->flush().
|
|
$this->writeCache = $data;
|
|
|
|
// Clear $data ready for next round
|
|
$data = '';
|
|
//
|
|
} else {
|
|
|
|
// Read the chunk from the start of $data
|
|
$chunk = substr( $data, 0, 6126 );
|
|
|
|
$encrypted = $this->preWriteEncrypt( $chunk, $this->keyfile );
|
|
|
|
// Write the data chunk to disk. This will be
|
|
// attended to the last data chunk if the file
|
|
// being handled totals more than 6126 bytes
|
|
fwrite( $this->handle, $encrypted );
|
|
|
|
$writtenLen = strlen( $encrypted );
|
|
//fseek( $this->handle, $writtenLen, SEEK_CUR );
|
|
|
|
// Remove the chunk we just processed from
|
|
// $data, leaving only unprocessed data in $data
|
|
// var, for handling on the next round
|
|
$data = substr( $data, 6126 );
|
|
|
|
}
|
|
|
|
}
|
|
|
|
$this->size = max( $this->size, $pointer + $length );
|
|
|
|
return $length;
|
|
|
|
}
|
|
|
|
|
|
public function stream_set_option( $option, $arg1, $arg2 ) {
|
|
switch($option) {
|
|
case STREAM_OPTION_BLOCKING:
|
|
stream_set_blocking( $this->handle, $arg1 );
|
|
break;
|
|
case STREAM_OPTION_READ_TIMEOUT:
|
|
stream_set_timeout( $this->handle, $arg1, $arg2 );
|
|
break;
|
|
case STREAM_OPTION_WRITE_BUFFER:
|
|
stream_set_write_buffer( $this->handle, $arg1, $arg2 );
|
|
}
|
|
}
|
|
|
|
public function stream_stat() {
|
|
return fstat($this->handle);
|
|
}
|
|
|
|
public function stream_lock( $mode ) {
|
|
flock( $this->handle, $mode );
|
|
}
|
|
|
|
public function stream_flush() {
|
|
|
|
return fflush( $this->handle );
|
|
// Not a typo: http://php.net/manual/en/function.fflush.php
|
|
|
|
}
|
|
|
|
public function stream_eof() {
|
|
return feof($this->handle);
|
|
}
|
|
|
|
private function flush() {
|
|
|
|
if ( $this->writeCache ) {
|
|
|
|
// Set keyfile property for file in question
|
|
$this->getKey();
|
|
|
|
$encrypted = $this->preWriteEncrypt( $this->writeCache, $this->keyfile );
|
|
|
|
fwrite( $this->handle, $encrypted );
|
|
|
|
$this->writeCache = '';
|
|
|
|
}
|
|
|
|
}
|
|
|
|
public function stream_close() {
|
|
|
|
$this->flush();
|
|
|
|
if (
|
|
$this->meta['mode']!='r'
|
|
and $this->meta['mode']!='rb'
|
|
) {
|
|
|
|
\OC\Files\Filesystem::putFileInfo( $this->path, array( 'encrypted' => true, 'size' => $this->size ), '' );
|
|
|
|
}
|
|
|
|
return fclose( $this->handle );
|
|
|
|
}
|
|
|
|
}
|