Merge pull request #27407 from nextcloud/backport/24966/stable20

[stable20] avoid fread on directories and unencrypted files

lib/private/Files/Storage/Wrapper/Encryption.php

@@ -923,21 +923,20 @@ class Encryption extends Wrapper {
 			$path = $realFile;
 		}
 
-		$firstBlock = $this->readFirstBlock($path);
-		$result = $this->parseRawHeader($firstBlock);
+		$result = [];
+		
+		// first check if it is an encrypted file at all
+		// We would do query to filecache only if we know that entry in filecache exists
+		
+		$info = $this->getCache()->get($path);
+		if (isset($info['encrypted']) && $info['encrypted'] === true) {
+			$firstBlock = $this->readFirstBlock($path);
+			$result = $this->parseRawHeader($firstBlock);
 
-		// if the header doesn't contain a encryption module we check if it is a
-		// legacy file. If true, we add the default encryption module
-		if (!isset($result[Util::HEADER_ENCRYPTION_MODULE_KEY])) {
-			if (!empty($result)) {
+			// if the header doesn't contain a encryption module we check if it is a
+			// legacy file. If true, we add the default encryption module
+			if (!isset($result[Util::HEADER_ENCRYPTION_MODULE_KEY]) && (!empty($result) || $exists)) {
 				$result[Util::HEADER_ENCRYPTION_MODULE_KEY] = 'OC_DEFAULT_MODULE';
-			} elseif ($exists) {
-				// if the header was empty we have to check first if it is a encrypted file at all
-				// We would do query to filecache only if we know that entry in filecache exists
-				$info = $this->getCache()->get($path);
-				if (isset($info['encrypted']) && $info['encrypted'] === true) {
-					$result[Util::HEADER_ENCRYPTION_MODULE_KEY] = 'OC_DEFAULT_MODULE';
-				}
 			}
 		}
 

tests/lib/Files/Storage/Wrapper/EncryptionTest.php

@@ -573,6 +573,14 @@ class EncryptionTest extends Storage {
 					$this->arrayCache
 				]
 			)->getMock();
+		
+		$cache = $this->getMockBuilder('\OC\Files\Cache\Cache')
+			->disableOriginalConstructor()->getMock();
+		$cache->expects($this->any())
+			->method('get')
+			->willReturnCallback(function ($path) {
+				return ['encrypted' => true, 'path' => $path];
+			});
 
 		$instance = $this->getMockBuilder('\OC\Files\Storage\Wrapper\Encryption')
 			->setConstructorArgs(
@@ -586,9 +594,11 @@ class EncryptionTest extends Storage {
 					$this->encryptionManager, $util, $this->logger, $this->file, null, $this->keyStore, $this->update, $this->mountManager, $this->arrayCache
 				]
 			)
-			->setMethods(['readFirstBlock', 'parseRawHeader'])
+			->setMethods(['getCache','readFirstBlock', 'parseRawHeader'])
 			->getMock();
-
+		
+		$instance->expects($this->once())->method('getCache')->willReturn($cache);
+		
 		$instance->expects($this->once())->method(('parseRawHeader'))
 			->willReturn([Util::HEADER_ENCRYPTION_MODULE_KEY => 'OC_DEFAULT_MODULE']);
 
@@ -661,8 +671,8 @@ class EncryptionTest extends Storage {
 			->setMethods(['readFirstBlock', 'parseRawHeader', 'getCache'])
 			->getMock();
 
-		$instance->expects($this->once())->method(('parseRawHeader'))->willReturn($header);
-		$instance->expects($this->any())->method('getCache')->willReturn($cache);
+		$instance->expects($this->any())->method(('parseRawHeader'))->willReturn($header);
+		$instance->expects($this->once())->method('getCache')->willReturn($cache);
 
 		$result = $this->invokePrivate($instance, 'getHeader', ['test.txt']);
 		$this->assertSameSize($expected, $result);