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Merge pull request #15834 from owncloud/make-temporary-file-really-unique 

Fix collision on temporary files + adjust permissions
This commit is contained in:
Lukas Reschke 2015-04-25 23:18:26 +02:00
parent 7855174879 155ae44bc6
commit 4dfdaf741c
2 changed files with 86 additions and 42 deletions
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99
lib/private/tempmanager.php
View File

@ -2,6 +2,7 @@
/**
* @author Morris Jobke <hey@morrisjobke.de>
* @author Robin Appelman <icewind@owncloud.com>
* @author Lukas Reschke <lukas@owncloud.com>
*
* @copyright Copyright (c) 2015, ownCloud, Inc.
* @license AGPL-3.0
@ -26,24 +27,14 @@ use OCP\ILogger;
use OCP\ITempManager;
class TempManager implements ITempManager {
/**
* Current temporary files and folders
*
* @var string[]
*/
protected $current = array();
/**
* i.e. /tmp on linux systems
*
* @var string
*/
/** @var string[] Current temporary files and folders, used for cleanup */
protected $current = [];
/** @var string i.e. /tmp on linux systems */
protected $tmpBaseDir;
/**
* @var \OCP\ILogger
*/
/** @var ILogger */
protected $log;
/** Prefix */
const TMP_PREFIX = 'oc_tmp_';
/**
* @param string $baseDir
@ -55,35 +46,55 @@ class TempManager implements ITempManager {
}
/**
* @param string $postFix
* Builds the filename with suffix and removes potential dangerous characters
* such as directory separators.
*
* @param string $absolutePath Absolute path to the file / folder
* @param string $postFix Postfix appended to the temporary file name, may be user controlled
* @return string
*/
protected function generatePath($postFix) {
if ($postFix) {
private function buildFileNameWithSuffix($absolutePath, $postFix = '') {
if($postFix !== '') {
$postFix = '.' . ltrim($postFix, '.');
$postFix = str_replace(['\\', '/'], '', $postFix);
$absolutePath .= '-';
}
$postFix = str_replace(['\\', '/'], '', $postFix);
return $this->tmpBaseDir . '/oc_tmp_' . md5(time() . rand()) . $postFix;
return $absolutePath . $postFix;
}
/**
* Create a temporary file and return the path
*
* @param string $postFix
* @param string $postFix Postfix appended to the temporary file name
* @return string
*/
public function getTemporaryFile($postFix = '') {
$file = $this->generatePath($postFix);
if (is_writable($this->tmpBaseDir)) {
touch($file);
// To create an unique file and prevent the risk of race conditions
// or duplicated temporary files by other means such as collisions
// we need to create the file using `tempnam` and append a possible
// postfix to it later
$file = tempnam($this->tmpBaseDir, self::TMP_PREFIX);
$this->current[] = $file;
// If a postfix got specified sanitize it and create a postfixed
// temporary file
if($postFix !== '') {
$fileNameWithPostfix = $this->buildFileNameWithSuffix($file, $postFix);
touch($fileNameWithPostfix);
chmod($fileNameWithPostfix, 0600);
$this->current[] = $fileNameWithPostfix;
return $fileNameWithPostfix;
}
return $file;
} else {
$this->log->warning(
'Can not create a temporary file in directory {dir}. Check it exists and has correct permissions',
array(
'dir' => $this->tmpBaseDir
)
[
'dir' => $this->tmpBaseDir,
]
);
return false;
}
@ -92,21 +103,30 @@ class TempManager implements ITempManager {
/**
* Create a temporary folder and return the path
*
* @param string $postFix
* @param string $postFix Postfix appended to the temporary folder name
* @return string
*/
public function getTemporaryFolder($postFix = '') {
$path = $this->generatePath($postFix);
if (is_writable($this->tmpBaseDir)) {
mkdir($path);
// To create an unique directory and prevent the risk of race conditions
// or duplicated temporary files by other means such as collisions
// we need to create the file using `tempnam` and append a possible
// postfix to it later
$uniqueFileName = tempnam($this->tmpBaseDir, self::TMP_PREFIX);
$this->current[] = $uniqueFileName;
// Build a name without postfix
$path = $this->buildFileNameWithSuffix($uniqueFileName . '-folder', $postFix);
mkdir($path, 0700);
$this->current[] = $path;
return $path . '/';
} else {
$this->log->warning(
'Can not create a temporary folder in directory {dir}. Check it exists and has correct permissions',
array(
'dir' => $this->tmpBaseDir
)
[
'dir' => $this->tmpBaseDir,
]
);
return false;
}
@ -119,6 +139,9 @@ class TempManager implements ITempManager {
$this->cleanFiles($this->current);
}
/**
* @param string[] $files
*/
protected function cleanFiles($files) {
foreach ($files as $file) {
if (file_exists($file)) {
@ -127,10 +150,10 @@ class TempManager implements ITempManager {
} catch (\UnexpectedValueException $ex) {
$this->log->warning(
"Error deleting temporary file/folder: {file} - Reason: {error}",
array(
[
'file' => $file,
'error' => $ex->getMessage()
)
'error' => $ex->getMessage(),
]
);
}
}
@ -151,11 +174,11 @@ class TempManager implements ITempManager {
*/
protected function getOldFiles() {
$cutOfTime = time() - 3600;
$files = array();
$files = [];
$dh = opendir($this->tmpBaseDir);
if ($dh) {
while (($file = readdir($dh)) !== false) {
if (substr($file, 0, 7) === 'oc_tmp_') {
if (substr($file, 0, 7) === self::TMP_PREFIX) {
$path = $this->tmpBaseDir . '/' . $file;
$mtime = filemtime($path);
if ($mtime < $cutOfTime) {

29
tests/lib/tempmanager.php
View File

@ -152,16 +152,37 @@ class TempManager extends \Test\TestCase {
$this->assertFalse($manager->getTemporaryFolder());
}
public function testGeneratePathTraversal() {
public function testBuildFileNameWithPostfix() {
$logger = $this->getMock('\Test\NullLogger');
$tmpManager = \Test_Helper::invokePrivate(
$this->getManager($logger),
'generatePath',
['../Traversal\\../FileName']
'buildFileNameWithSuffix',
['/tmp/myTemporaryFile', 'postfix']
);
$this->assertEquals('/tmp/myTemporaryFile-.postfix', $tmpManager);
}
public function testBuildFileNameWithoutPostfix() {
$logger = $this->getMock('\Test\NullLogger');
$tmpManager = \Test_Helper::invokePrivate(
$this->getManager($logger),
'buildFileNameWithSuffix',
['/tmp/myTemporaryFile', '']
);
$this->assertEquals('/tmp/myTemporaryFile', $tmpManager);
}
public function testBuildFileNameWithSuffixPathTraversal() {
$logger = $this->getMock('\Test\NullLogger');
$tmpManager = \Test_Helper::invokePrivate(
$this->getManager($logger),
'buildFileNameWithSuffix',
['foo', '../Traversal\\../FileName']
);
$this->assertStringEndsNotWith('./Traversal\\../FileName', $tmpManager);
$this->assertStringEndsWith('.Traversal..FileName', $tmpManager);
}
}