extend the encryption stream wrapper to handle local files and add a fall back for file size calculation if the storage doesn't support fseek

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;
 
@@ -488,7 +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;
@@ -509,6 +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

@@ -473,7 +473,9 @@ class Util {
 		$data = '';
 		$handle = $this->view->fopen($path, 'r');
 		if (is_resource($handle)) {
-			if (fseek($handle, -24, SEEK_END) === 0) {
+			// 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
@@ -537,7 +539,20 @@ 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);