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dissalow symlinks in local storages that point outside the datadir
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icewind1991 committed Jun 7, 2016
1 parent 46fe2dd commit 7b1b723
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Showing 3 changed files with 63 additions and 2 deletions.
30 changes: 29 additions & 1 deletion lib/private/Files/Storage/Local.php
Original file line number Diff line number Diff line change
Expand Up @@ -33,20 +33,31 @@
*/

namespace OC\Files\Storage;

use OCP\Files\ForbiddenException;

/**
* for local filestore, we only have to map the paths
*/
class Local extends \OC\Files\Storage\Common {
protected $datadir;

protected $dataDirLength;

protected $allowSymlinks = false;

protected $realDataDir;

public function __construct($arguments) {
if (!isset($arguments['datadir']) || !is_string($arguments['datadir'])) {
throw new \InvalidArgumentException('No data directory set for local storage');
}
$this->datadir = $arguments['datadir'];
$this->realDataDir = rtrim(realpath($this->datadir), '/') . '/';
if (substr($this->datadir, -1) !== '/') {
$this->datadir .= '/';
}
$this->dataDirLength = strlen($this->realDataDir);
}

public function __destruct() {
Expand Down Expand Up @@ -337,10 +348,27 @@ public function hasUpdated($path, $time) {
*
* @param string $path
* @return string
* @throws ForbiddenException
*/
public function getSourcePath($path) {
$fullPath = $this->datadir . $path;
return $fullPath;
if ($this->allowSymlinks || $path === '') {
return $fullPath;
}
$pathToResolve = $fullPath;
$realPath = realpath($pathToResolve);
while ($realPath === false) { // for non existing files check the parent directory
$pathToResolve = dirname($pathToResolve);
$realPath = realpath($pathToResolve);
}
if ($realPath) {
$realPath = $realPath . '/';
}
if (substr($realPath, 0, $this->dataDirLength) === $this->realDataDir) {
return $fullPath;
} else {
throw new ForbiddenException("Following symlinks is not allowed ('$fullPath' -> '$realPath' not inside '{$this->realDataDir}')", false);
}
}

/**
Expand Down
4 changes: 3 additions & 1 deletion lib/private/legacy/helper.php
Original file line number Diff line number Diff line change
Expand Up @@ -206,7 +206,9 @@ static function rmdirr($dir, $deleteSelf = true) {

foreach ($files as $fileInfo) {
/** @var SplFileInfo $fileInfo */
if ($fileInfo->isDir()) {
if ($fileInfo->isLink()) {
unlink($fileInfo->getPathname());
} else if ($fileInfo->isDir()) {
rmdir($fileInfo->getRealPath());
} else {
unlink($fileInfo->getRealPath());
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31 changes: 31 additions & 0 deletions tests/lib/Files/Storage/LocalTest.php
Original file line number Diff line number Diff line change
Expand Up @@ -84,5 +84,36 @@ public function testInvalidArgumentsEmptyArray() {
public function testInvalidArgumentsNoArray() {
new \OC\Files\Storage\Local(null);
}

/**
* @expectedException \OCP\Files\ForbiddenException
*/
public function testDisallowSymlinksOutsideDatadir() {
$subDir1 = $this->tmpDir . 'sub1';
$subDir2 = $this->tmpDir . 'sub2';
$sym = $this->tmpDir . 'sub1/sym';
mkdir($subDir1);
mkdir($subDir2);

symlink($subDir2, $sym);

$storage = new \OC\Files\Storage\Local(['datadir' => $subDir1]);

$storage->file_put_contents('sym/foo', 'bar');
}

public function testDisallowSymlinksInsideDatadir() {
$subDir1 = $this->tmpDir . 'sub1';
$subDir2 = $this->tmpDir . 'sub1/sub2';
$sym = $this->tmpDir . 'sub1/sym';
mkdir($subDir1);
mkdir($subDir2);

symlink($subDir2, $sym);

$storage = new \OC\Files\Storage\Local(['datadir' => $subDir1]);

$storage->file_put_contents('sym/foo', 'bar');
}
}

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