177 lines
5.1 KiB
PHP
177 lines
5.1 KiB
PHP
<?php
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/**
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* ownCloud
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*
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* @author Robin Appelman
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* @copyright 2011 Robin Appelman icewind1991@gmail.com
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
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* License as published by the Free Software Foundation; either
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* version 3 of the License, or any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU AFFERO GENERAL PUBLIC LICENSE for more details.
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*
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* You should have received a copy of the GNU Affero General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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/**
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* transparently encrypted filestream
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*
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* you can use it as wrapper around an existing stream by setting OC_CryptStream::$sourceStreams['foo']=array('path'=>$path,'stream'=>$stream)
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* and then fopen('crypt://streams/foo');
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*/
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class OC_CryptStream{
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public static $sourceStreams=array();
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private $source;
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private $path;
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private $readBuffer;//for streams that dont support seeking
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private $meta=array();//header/meta for source stream
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private $count;
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private $writeCache;
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private $size;
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private static $rootView;
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public function stream_open($path, $mode, $options, &$opened_path){
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if(!self::$rootView){
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self::$rootView=new OC_FilesystemView('');
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}
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$path=str_replace('crypt://','',$path);
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if(dirname($path)=='streams' and isset(self::$sourceStreams[basename($path)])){
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$this->source=self::$sourceStreams[basename($path)]['stream'];
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$this->path=self::$sourceStreams[basename($path)]['path'];
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$this->size=self::$sourceStreams[basename($path)]['size'];
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}else{
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$this->path=$path;
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if($mode=='w' or $mode=='w+' or $mode=='wb' or $mode=='wb+'){
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$this->size=0;
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}else{
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$this->size=self::$rootView->filesize($path,$mode);
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}
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OC_FileProxy::$enabled=false;//disable fileproxies so we can open the source file
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$this->source=self::$rootView->fopen($path,$mode);
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OC_FileProxy::$enabled=true;
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if(!is_resource($this->source)){
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OCP\Util::writeLog('files_encryption','failed to open '.$path,OCP\Util::ERROR);
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}
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}
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if(is_resource($this->source)){
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$this->meta=stream_get_meta_data($this->source);
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}
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return is_resource($this->source);
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}
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public function stream_seek($offset, $whence=SEEK_SET){
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$this->flush();
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fseek($this->source,$offset,$whence);
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}
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public function stream_tell(){
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return ftell($this->source);
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}
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public function stream_read($count){
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//$count will always be 8192 https://bugs.php.net/bug.php?id=21641
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//This makes this function a lot simpler but will breake everything the moment it's fixed
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$this->writeCache='';
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if($count!=8192){
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OCP\Util::writeLog('files_encryption','php bug 21641 no longer holds, decryption will not work',OCP\Util::FATAL);
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die();
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}
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$pos=ftell($this->source);
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$data=fread($this->source,8192);
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if(strlen($data)){
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$result=OC_Crypt::decrypt($data);
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}else{
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$result='';
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}
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$length=$this->size-$pos;
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if($length<8192){
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$result=substr($result,0,$length);
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}
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return $result;
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}
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public function stream_write($data){
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$length=strlen($data);
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$written=0;
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$currentPos=ftell($this->source);
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if($this->writeCache){
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$data=$this->writeCache.$data;
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$this->writeCache='';
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}
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if($currentPos%8192!=0){
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//make sure we always start on a block start
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fseek($this->source,-($currentPos%8192),SEEK_CUR);
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$encryptedBlock=fread($this->source,8192);
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fseek($this->source,-($currentPos%8192),SEEK_CUR);
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$block=OC_Crypt::decrypt($encryptedBlock);
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$data=substr($block,0,$currentPos%8192).$data;
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fseek($this->source,-($currentPos%8192),SEEK_CUR);
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}
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$currentPos=ftell($this->source);
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while($remainingLength=strlen($data)>0){
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if($remainingLength<8192){
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$this->writeCache=$data;
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$data='';
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}else{
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$encrypted=OC_Crypt::encrypt(substr($data,0,8192));
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fwrite($this->source,$encrypted);
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$data=substr($data,8192);
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}
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}
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$this->size=max($this->size,$currentPos+$length);
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return $length;
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}
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public function stream_set_option($option,$arg1,$arg2){
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switch($option){
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case STREAM_OPTION_BLOCKING:
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stream_set_blocking($this->source,$arg1);
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break;
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case STREAM_OPTION_READ_TIMEOUT:
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stream_set_timeout($this->source,$arg1,$arg2);
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break;
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case STREAM_OPTION_WRITE_BUFFER:
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stream_set_write_buffer($this->source,$arg1,$arg2);
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}
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}
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public function stream_stat(){
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return fstat($this->source);
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}
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public function stream_lock($mode){
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flock($this->source,$mode);
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}
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public function stream_flush(){
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return fflush($this->source);
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}
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public function stream_eof(){
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return feof($this->source);
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}
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private function flush(){
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if($this->writeCache){
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$encrypted=OC_Crypt::encrypt($this->writeCache);
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fwrite($this->source,$encrypted);
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$this->writeCache='';
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}
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}
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public function stream_close(){
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$this->flush();
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if($this->meta['mode']!='r' and $this->meta['mode']!='rb'){
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OC_FileCache::put($this->path,array('encrypted'=>true,'size'=>$this->size),'');
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}
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return fclose($this->source);
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}
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}
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