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make use of the fact that stream_read will always read 8192 bytes for encryption stream 

https://bugs.php.net/bug.php?id=21641
This commit is contained in:
Robin Appelman 2012-04-17 23:10:14 +02:00
parent 26e9a0dd13
commit b39c3d4c4e
2 changed files with 71 additions and 23 deletions
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38
apps/files_encryption/lib/cryptstream.php
View File

@ -64,29 +64,19 @@ class OC_CryptStream{
}
public function stream_read($count){
$pos=0;
$currentPos=ftell($this->source);
$offset=$currentPos%8192;
$result='';
if($offset>0){
if($this->meta['seekable']){
fseek($this->source,-$offset,SEEK_CUR);//if seeking isnt supported the internal read buffer will be used
}else{
$pos=strlen($this->readBuffer);
$result=$this->readBuffer;
}
//$count will always be 8192 https://bugs.php.net/bug.php?id=21641
//This makes this function a lot simpler but will breake everything the moment it's fixed
if($count!=8192){
OC_Log::write('files_encryption','php bug 21641 no longer holds, decryption will not work',OC_Log::FATAL);
die();
}
while($count>$pos){
$data=fread($this->source,8192);
$pos+=8192;
if(strlen($data)){
$result.=OC_Crypt::decrypt($data);
}
$data=fread($this->source,8192);
if(strlen($data)){
$result=OC_Crypt::decrypt($data);
}else{
$result='';
}
if(!$this->meta['seekable']){
$this->readBuffer=substr($result,$count);
}
return substr($result,0,$count);
return $result;
}
public function stream_write($data){
@ -107,8 +97,10 @@ class OC_CryptStream{
$oldPos=ftell($this->source);
$encryptedBlock=fread($this->source,8192);
fseek($this->source,$oldPos);
$block=OC_Crypt::decrypt($encryptedBlock);
$data.=substr($block,strlen($data));
if($encryptedBlock){
$block=OC_Crypt::decrypt($encryptedBlock);
$data.=substr($block,strlen($data));
}
}
$encrypted=OC_Crypt::encrypt(substr($data,0,8192));
fwrite($this->source,$encrypted);

56
apps/files_encryption/tests/stream.php Normal file
View File

@ -0,0 +1,56 @@
<?php
/**
* Copyright (c) 2012 Robin Appelman <icewind@owncloud.com>
* This file is licensed under the Affero General Public License version 3 or
* later.
* See the COPYING-README file.
*/
class Test_CryptStream extends UnitTestCase {
private $tmpFiles=array();
function testStream(){
$stream=$this->getStream('test1','w');
fwrite($stream,'foobar');
fclose($stream);
$stream=$this->getStream('test1','r');
$data=fread($stream,6);
fclose($stream);
$this->assertEqual('foobar',$data);
$file=OC::$SERVERROOT.'/3rdparty/MDB2.php';
$source=fopen($file,'r');
$target=$this->getStream('test2','w');
OC_Helper::streamCopy($source,$target);
fclose($target);
fclose($source);
$stream=$this->getStream('test2','r');
$data=stream_get_contents($stream);
$original=file_get_contents($file);
$this->assertEqual(strlen($original),strlen($data));
$this->assertEqual($original,$data);
}
/**
* get a cryptstream to a temporary file
* @param string $id
* @param string $mode
* @return resource
*/
function getStream($id,$mode){
if($id===''){
$id=uniqid();
}
if(!isset($this->tmpFiles[$id])){
$file=OC_Helper::tmpFile();
$this->tmpFiles[$id]=$file;
}else{
$file=$this->tmpFiles[$id];
}
$stream=fopen($file,$mode);
OC_CryptStream::$sourceStreams[$id]=array('path'=>'dummy','stream'=>$stream);
return fopen('crypt://streams/'.$id,$mode);
}
}