Merge pull request #6495 from owncloud/enc_fseek_fallback

Added fseek fallback to the encryption app

apps/files_encryption/lib/helper.php

@@ -29,6 +29,8 @@ namespace OCA\Encryption;
  */
 class Helper {
 
+	private static $tmpFileMapping; // Map tmp files to files in data/user/files
+
 	/**
 	 * @brief register share related hooks
 	 *
@@ -423,5 +425,27 @@ class Helper {
 	public static function escapeGlobPattern($path) {
 		return preg_replace('/(\*|\?|\[)/', '[$1]', $path);
 	}
+
+	/**
+	 * @brief remember from which file the tmp file (getLocalFile() call) was created
+	 * @param string $tmpFile path of tmp file
+	 * @param string $originalFile path of the original file relative to data/
+	 */
+	public static function addTmpFileToMapper($tmpFile, $originalFile) {
+		self::$tmpFileMapping[$tmpFile] = $originalFile;
+	}
+
+	/**
+	 * @brief get the path of the original file
+	 * @param string $tmpFile path of the tmp file
+	 * @return mixed path of the original file or false
+	 */
+	public static function getPathFromTmpFile($tmpFile) {
+		if (isset(self::$tmpFileMapping[$tmpFile])) {
+			return self::$tmpFileMapping[$tmpFile];
+		}
+
+		return false;
+	}
 }
 

apps/files_encryption/lib/stream.php

@@ -64,6 +64,9 @@ class Stream {
 	private $publicKey;
 	private $encKeyfile;
 	private $newFile; // helper var, we only need to write the keyfile for new files
+	private $isLocalTmpFile = false; // do we operate on a local tmp file
+	private $localTmpFile; // path of local tmp file
+
 	/**
 	 * @var \OC\Files\View
 	 */
@@ -91,13 +94,18 @@ class Stream {
 			$this->rootView = new \OC_FilesystemView('/');
 		}
 
-
 		$this->session = new \OCA\Encryption\Session($this->rootView);
 
 		$this->privateKey = $this->session->getPrivateKey();
 
-		// rawPath is relative to the data directory
-		$this->rawPath = \OC\Files\Filesystem::normalizePath(str_replace('crypt://', '', $path));
+		$normalizedPath = \OC\Files\Filesystem::normalizePath(str_replace('crypt://', '', $path));
+		if ($originalFile = Helper::getPathFromTmpFile($normalizedPath)) {
+			$this->rawPath = $originalFile;
+			$this->isLocalTmpFile = true;
+			$this->localTmpFile = $normalizedPath;
+		} else {
+			$this->rawPath = $normalizedPath;
+		}
 
 		$this->userId = Helper::getUser($this->rawPath);
 
@@ -141,10 +149,14 @@ class Stream {
 				\OCA\Encryption\Helper::redirectToErrorPage($this->session);
 			}
 
-			$this->size = $this->rootView->filesize($this->rawPath, $mode);
+			$this->size = $this->rootView->filesize($this->rawPath);
 		}
 
-		$this->handle = $this->rootView->fopen($this->rawPath, $mode);
+		if ($this->isLocalTmpFile) {
+			$this->handle = fopen($this->localTmpFile, $mode);
+		} else {
+			$this->handle = $this->rootView->fopen($this->rawPath, $mode);
+		}
 
 		\OC_FileProxy::$enabled = $proxyStatus;
 
@@ -163,15 +175,26 @@ class Stream {
 
 	}
 
+	/**
+	 * @brief Returns the current position of the file pointer
+	 * @return int  position of the file pointer
+	 */
+	public function stream_tell() {
+		return ftell($this->handle);
+	}
+
 	/**
 	 * @param $offset
 	 * @param int $whence
+	 * @return bool true if fseek was successful, otherwise false
 	 */
 	public function stream_seek($offset, $whence = SEEK_SET) {
 
 		$this->flush();
 
-		fseek($this->handle, $offset, $whence);
+		// this wrapper needs to return "true" for success.
+		// the fseek call itself returns 0 on succeess
+		return !fseek($this->handle, $offset, $whence);
 
 	}
 
@@ -477,7 +500,7 @@ class Stream {
 		if ($this->privateKey === false) {
 
 			// cleanup
-			if ($this->meta['mode'] !== 'r' && $this->meta['mode'] !== 'rb') {
+			if ($this->meta['mode'] !== 'r' && $this->meta['mode'] !== 'rb' && !$this->isLocalTmpFile) {
 
 				// Disable encryption proxy to prevent recursive calls
 				$proxyStatus = \OC_FileProxy::$enabled;
@@ -498,6 +521,7 @@ class Stream {
 		if (
 				$this->meta['mode'] !== 'r' &&
 				$this->meta['mode'] !== 'rb' &&
+				$this->isLocalTmpFile === false &&
 				$this->size > 0 &&
 				$this->unencryptedSize > 0
 		) {

apps/files_encryption/lib/util.php

@@ -429,8 +429,22 @@ class Util {
 		// we only need 24 byte from the last chunk
 		$data = '';
 		$handle = $this->view->fopen($path, 'r');
-		if (is_resource($handle) && !fseek($handle, -24, SEEK_END)) {
-			$data = fgets($handle);
+		if (is_resource($handle)) {
+			// suppress fseek warining, we handle the case that fseek doesn't
+			// work in the else branch
+			if (@fseek($handle, -24, SEEK_END) === 0) {
+				$data = fgets($handle);
+			} else {
+				// if fseek failed on the storage we create a local copy from the file
+				// and read this one
+				fclose($handle);
+				$localFile = $this->view->getLocalFile($path);
+				$handle = fopen($localFile, 'r');
+				if (is_resource($handle) && fseek($handle, -24, SEEK_END) === 0) {
+					$data = fgets($handle);
+				}
+			}
+			fclose($handle);
 		}
 
 		// re-enable proxy
@@ -482,7 +496,20 @@ class Util {
 				$lastChunckPos = ($lastChunkNr * 8192);
 
 				// seek to end
-				fseek($stream, $lastChunckPos);
+				if (@fseek($stream, $lastChunckPos) === -1) {
+					// storage doesn't support fseek, we need a local copy
+					fclose($stream);
+					$localFile = $this->view->getLocalFile($path);
+					Helper::addTmpFileToMapper($localFile, $path);
+					$stream = fopen('crypt://' . $localFile, "r");
+					if (fseek($stream, $lastChunckPos) === -1) {
+						// if fseek also fails on the local storage, than
+						// there is nothing we can do
+						fclose($stream);
+						\OCP\Util::writeLog('Encryption library', 'couldn\'t determine size of "' . $path, \OCP\Util::ERROR);
+						return $result;
+					}
+				}
 
 				// get the content of the last chunk
 				$lastChunkContent = fread($stream, $lastChunkSize);

apps/files_encryption/tests/stream.php

@@ -180,4 +180,43 @@ class Test_Encryption_Stream extends \PHPUnit_Framework_TestCase {
 		// tear down
 		$view->unlink($filename);
 	}
+
+	/**
+	 * @medium
+	 * @brief test if stream wrapper can read files outside from the data folder
+	 */
+	function testStreamFromLocalFile() {
+
+		$filename = '/' . $this->userId . '/files/' . 'tmp-' . time().'.txt';
+
+		$tmpFilename = "/tmp/" . time() . ".txt";
+
+		// write an encrypted file
+		$cryptedFile = $this->view->file_put_contents($filename, $this->dataShort);
+
+		// Test that data was successfully written
+		$this->assertTrue(is_int($cryptedFile));
+
+		// create a copy outside of the data folder in /tmp
+		$proxyStatus = \OC_FileProxy::$enabled;
+		\OC_FileProxy::$enabled = false;
+		$encryptedContent = $this->view->file_get_contents($filename);
+		\OC_FileProxy::$enabled = $proxyStatus;
+
+		file_put_contents($tmpFilename, $encryptedContent);
+
+		\OCA\Encryption\Helper::addTmpFileToMapper($tmpFilename, $filename);
+
+		// try to read the file from /tmp
+		$handle = fopen("crypt://".$tmpFilename, "r");
+		$contentFromTmpFile = stream_get_contents($handle);
+
+		// check if it was successful
+		$this->assertEquals($this->dataShort, $contentFromTmpFile);
+
+		// clean up
+		unlink($tmpFilename);
+		$this->view->unlink($filename);
+
+	}
 }

apps/files_encryption/tests/util.php

@@ -132,6 +132,41 @@ class Test_Encryption_Util extends \PHPUnit_Framework_TestCase {
 
 	}
 
+	/**
+	 * @medium
+	 * @brief test detection of encrypted files
+	 */
+	function testIsEncryptedPath() {
+
+		$util = new Encryption\Util($this->view, $this->userId);
+
+		self::loginHelper($this->userId);
+
+		$unencryptedFile = '/tmpUnencrypted-' . time() . '.txt';
+		$encryptedFile =  '/tmpEncrypted-' . time() . '.txt';
+
+		// Disable encryption proxy to write a unencrypted file
+		$proxyStatus = \OC_FileProxy::$enabled;
+		\OC_FileProxy::$enabled = false;
+
+		$this->view->file_put_contents($this->userId . '/files/' . $unencryptedFile, $this->dataShort);
+
+		// Re-enable proxy - our work is done
+		\OC_FileProxy::$enabled = $proxyStatus;
+
+		// write a encrypted file
+		$this->view->file_put_contents($this->userId . '/files/' . $encryptedFile, $this->dataShort);
+
+		// test if both files are detected correctly
+		$this->assertFalse($util->isEncryptedPath($this->userId . '/files/' . $unencryptedFile));
+		$this->assertTrue($util->isEncryptedPath($this->userId . '/files/' . $encryptedFile));
+
+		// cleanup
+		$this->view->unlink($this->userId . '/files/' . $unencryptedFile, $this->dataShort);
+		$this->view->unlink($this->userId . '/files/' . $encryptedFile, $this->dataShort);
+
+	}
+
 	/**
 	 * @medium
 	 * @brief test setup of encryption directories