Prevent deleting storage root

Storage mount points are not deletable, so make sure that the unlink
operation and its hooks aren't run in such cases.

Note that some storages might recursively delete their contents when
calling unlink on their root. This fix prevents that as well.

2 files changed, 55 insertions, 0 deletions

diff --git a/lib/private/files/view.php b/lib/private/files/view.php
index ac45a881331..8893911ed5d 100644
--- a/lib/private/files/view.php
+++ b/lib/private/files/view.php
@@ -336,6 +336,19 @@ class View {
 	}
 
 	public function unlink($path) {
+		if ($path === '' || $path === '/') {
+			// do not allow deleting the root
+			return false;
+		}
+		$postFix = (substr($path, -1, 1) === '/') ? '/' : '';
+		$absolutePath = Filesystem::normalizePath($this->getAbsolutePath($path));
+		list($storage, $internalPath) = Filesystem::resolvePath($absolutePath . $postFix);
+		if (!$internalPath || $internalPath === '' || $internalPath === '/') {
+			// do not allow deleting the storage's root / the mount point
+			// because for some storages it might delete the whole contents
+			// but isn't supposed to work that way
+			return false;
+		}
 		return $this->basicOperation('unlink', $path, array('delete'));
 	}
 
diff --git a/tests/lib/files/view.php b/tests/lib/files/view.php
index b59cef9f0da..76a7fd5f1ca 100644
--- a/tests/lib/files/view.php
+++ b/tests/lib/files/view.php
@@ -309,6 +309,48 @@ class View extends \PHPUnit_Framework_TestCase {
 	/**
 	 * @medium
 	 */
+	function testUnlink() {
+		$storage1 = $this->getTestStorage();
+		$storage2 = $this->getTestStorage();
+		\OC\Files\Filesystem::mount($storage1, array(), '/');
+		\OC\Files\Filesystem::mount($storage2, array(), '/substorage');
+
+		$rootView = new \OC\Files\View('');
+		$rootView->file_put_contents('/foo.txt', 'asd');
+		$rootView->file_put_contents('/substorage/bar.txt', 'asd');
+
+		$this->assertTrue($rootView->file_exists('foo.txt'));
+		$this->assertTrue($rootView->file_exists('substorage/bar.txt'));
+
+		$this->assertTrue($rootView->unlink('foo.txt'));
+		$this->assertTrue($rootView->unlink('substorage/bar.txt'));
+
+		$this->assertFalse($rootView->file_exists('foo.txt'));
+		$this->assertFalse($rootView->file_exists('substorage/bar.txt'));
+	}
+
+	/**
+	 * @medium
+	 */
+	function testUnlinkRootMustFail() {
+		$storage1 = $this->getTestStorage();
+		$storage2 = $this->getTestStorage();
+		\OC\Files\Filesystem::mount($storage1, array(), '/');
+		\OC\Files\Filesystem::mount($storage2, array(), '/substorage');
+
+		$rootView = new \OC\Files\View('');
+		$rootView->file_put_contents('/foo.txt', 'asd');
+		$rootView->file_put_contents('/substorage/bar.txt', 'asd');
+
+		$this->assertFalse($rootView->unlink(''));
+		$this->assertFalse($rootView->unlink('/'));
+		$this->assertFalse($rootView->unlink('substorage'));
+		$this->assertFalse($rootView->unlink('/substorage'));
+	}
+
+	/**
+	 * @medium
+	 */
 	function testTouch() {
 		$storage = $this->getTestStorage(true, '\Test\Files\TemporaryNoTouch');