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fix encryption header error 

When moving back the pointer to position 0 (using stream_seek), the pointer on the encrypted stream will be moved to the position immediately after the header. Reading the header again (invoked by stream_read) will cause an error, writing the header again (invoked by stream_write) will corrupt the file. Reading/writing the header should therefore happen when opening the file rather than upon read or write. Note that a side-effect of this PR is that empty files will still get an encryption header; I think that is OK, but it is different from how it was originally implemented.
This commit is contained in:
jknockaert 2015-04-21 14:21:53 +02:00 committed by Bjoern Schiessle
parent 4334e77035
commit 735f6cc037
1 changed files with 16 additions and 13 deletions
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29
lib/private/files/stream/encryption.php
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@ -221,15 +221,28 @@ class Encryption extends Wrapper {
|| $mode === 'w+'
|| $mode === 'wb'
|| $mode === 'wb+'
|| $mode === 'r+'
|| $mode === 'rb+'
) {
// We're writing a new file so start write counter with 0 bytes
$this->unencryptedSize = 0;
$this->size = 0;
$this->readOnly = false;
} else {
$this->readOnly = true;
}
if (
$mode === 'w'
|| $mode === 'w+'
|| $mode === 'wb'
|| $mode === 'wb+'
) {
// We're writing a new file so start write counter with 0 bytes
$this->unencryptedSize = 0;
$this->writeHeader();
$this->size = $this->util->getHeaderSize();
} else {
parent::stream_read($this->util->getHeaderSize());
}
$sharePath = $this->fullPath;
if (!$this->storage->file_exists($this->internalPath)) {
$sharePath = dirname($sharePath);
@ -250,11 +263,6 @@ class Encryption extends Wrapper {
$result = '';
// skip the header if we read the file from the beginning
if ($this->position === 0) {
parent::stream_read($this->util->getHeaderSize());
}
// $count = min($count, $this->unencryptedSize - $this->position);
while ($count > 0) {
$remainingLength = $count;
@ -281,11 +289,6 @@ class Encryption extends Wrapper {
public function stream_write($data) {
if ($this->position === 0) {
$this->writeHeader();
$this->size = $this->util->getHeaderSize();
}
$length = 0;
// loop over $data to fit it in 6126 sized unencrypted blocks
while (strlen($data) > 0) {