Make legacy cipher opt in

* Systems that upgrade have this enabled by default
* New systems disable it
* We'll have to add some wargning in the setup checks if this is enabled

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>

7 files changed, 181 insertions, 12 deletions

diff --git a/apps/encryption/appinfo/info.xml b/apps/encryption/appinfo/info.xml
index 0ef56e7e677..b01e66419a3 100644
--- a/apps/encryption/appinfo/info.xml
+++ b/apps/encryption/appinfo/info.xml
@@ -44,6 +44,7 @@
 		<command>OCA\Encryption\Command\EnableMasterKey</command>
 		<command>OCA\Encryption\Command\DisableMasterKey</command>
 		<command>OCA\Encryption\Command\RecoverUser</command>
+		<command>OCA\Encryption\Command\ScanLegacyFormat</command>
 	</commands>
 
 	<settings>
diff --git a/apps/encryption/composer/composer/autoload_classmap.php b/apps/encryption/composer/composer/autoload_classmap.php
index a071387a392..b8226a2793f 100644
--- a/apps/encryption/composer/composer/autoload_classmap.php
+++ b/apps/encryption/composer/composer/autoload_classmap.php
@@ -10,6 +10,7 @@ return array(
     'OCA\\Encryption\\Command\\DisableMasterKey' => $baseDir . '/../lib/Command/DisableMasterKey.php',
     'OCA\\Encryption\\Command\\EnableMasterKey' => $baseDir . '/../lib/Command/EnableMasterKey.php',
     'OCA\\Encryption\\Command\\RecoverUser' => $baseDir . '/../lib/Command/RecoverUser.php',
+    'OCA\\Encryption\\Command\\ScanLegacyFormat' => $baseDir . '/../lib/Command/ScanLegacyFormat.php',
     'OCA\\Encryption\\Controller\\RecoveryController' => $baseDir . '/../lib/Controller/RecoveryController.php',
     'OCA\\Encryption\\Controller\\SettingsController' => $baseDir . '/../lib/Controller/SettingsController.php',
     'OCA\\Encryption\\Controller\\StatusController' => $baseDir . '/../lib/Controller/StatusController.php',
diff --git a/apps/encryption/composer/composer/autoload_static.php b/apps/encryption/composer/composer/autoload_static.php
index 6ed6e72a87a..95c3c8d0223 100644
--- a/apps/encryption/composer/composer/autoload_static.php
+++ b/apps/encryption/composer/composer/autoload_static.php
@@ -25,6 +25,7 @@ class ComposerStaticInitEncryption
         'OCA\\Encryption\\Command\\DisableMasterKey' => __DIR__ . '/..' . '/../lib/Command/DisableMasterKey.php',
         'OCA\\Encryption\\Command\\EnableMasterKey' => __DIR__ . '/..' . '/../lib/Command/EnableMasterKey.php',
         'OCA\\Encryption\\Command\\RecoverUser' => __DIR__ . '/..' . '/../lib/Command/RecoverUser.php',
+        'OCA\\Encryption\\Command\\ScanLegacyFormat' => __DIR__ . '/..' . '/../lib/Command/ScanLegacyFormat.php',
         'OCA\\Encryption\\Controller\\RecoveryController' => __DIR__ . '/..' . '/../lib/Controller/RecoveryController.php',
         'OCA\\Encryption\\Controller\\SettingsController' => __DIR__ . '/..' . '/../lib/Controller/SettingsController.php',
         'OCA\\Encryption\\Controller\\StatusController' => __DIR__ . '/..' . '/../lib/Controller/StatusController.php',
diff --git a/apps/encryption/lib/Command/ScanLegacyFormat.php b/apps/encryption/lib/Command/ScanLegacyFormat.php
new file mode 100644
index 00000000000..3d13485af3f
--- /dev/null
+++ b/apps/encryption/lib/Command/ScanLegacyFormat.php
@@ -0,0 +1,140 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2020, Roeland Jago Douma <roeland@famdouma.nl>
+ *
+ * @author Roeland Jago Douma <roeland@famdouma.nl>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\Encryption\Command;
+
+use OC\Files\View;
+use OCA\Encryption\Util;
+use OCP\IConfig;
+use OCP\IUserManager;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Helper\QuestionHelper;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+class ScanLegacyFormat extends Command {
+
+	/** @var Util */
+	protected $util;
+
+	/** @var IConfig */
+	protected $config;
+
+	/** @var  QuestionHelper */
+	protected $questionHelper;
+
+	/** @var IUserManager */
+	private $userManager;
+
+	/** @var View */
+	private $rootView;
+
+	/**
+	 * @param Util $util
+	 * @param IConfig $config
+	 * @param QuestionHelper $questionHelper
+	 */
+	public function __construct(Util $util,
+								IConfig $config,
+								QuestionHelper $questionHelper,
+								IUserManager $userManager) {
+		parent::__construct();
+
+		$this->util = $util;
+		$this->config = $config;
+		$this->questionHelper = $questionHelper;
+		$this->userManager = $userManager;
+		$this->rootView = new View();
+	}
+
+	protected function configure() {
+		$this
+			->setName('encryption:scan:legacy-format')
+			->setDescription('Scan the files for the legacy format');
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output): int {
+		$result = true;
+
+		$output->writeln('Scanning all files for legacy encryption');
+
+		foreach ($this->userManager->getBackends() as $backend) {
+			$limit = 500;
+			$offset = 0;
+			do {
+				$users = $backend->getUsers('', $limit, $offset);
+				foreach ($users as $user) {
+					$output->writeln('Scanning all files for ' . $user);
+					$this->setupUserFS($user);
+					$result &= $this->scanFolder($output, '/' . $user);
+				}
+				$offset += $limit;
+			} while (count($users) >= $limit);
+		}
+
+		if ($result) {
+			$output->writeln('All scanned files are propperly encrypted. You can disable the legacy compatibility mode.');
+			return 0;
+		}
+
+		return 1;
+	}
+
+	private function scanFolder(OutputInterface $output, string $folder): bool {
+		$clean = true;
+
+		foreach ($this->rootView->getDirectoryContent($folder) as $item) {
+			$path = $folder . '/' . $item['name'];
+			if ($this->rootView->is_dir($path)) {
+				if ($this->scanFolder($output, $path) === false) {
+					$clean = false;
+				}
+			} else {
+				if (!$item->isEncrypted()) {
+					// ignore
+					continue;
+				}
+
+				$stats = $this->rootView->stat($path);
+				if (!isset($stats['hasHeader']) || $stats['hasHeader'] === false) {
+					$clean = false;
+					$output->writeln($path . ' does not have a proper header');
+				}
+			}
+		}
+
+		return $clean;
+	}
+
+	/**
+	 * setup user file system
+	 *
+	 * @param string $uid
+	 */
+	protected function setupUserFS($uid) {
+		\OC_Util::tearDownFS();
+		\OC_Util::setupFS($uid);
+	}
+}
diff --git a/apps/encryption/lib/Crypto/Crypt.php b/apps/encryption/lib/Crypto/Crypt.php
index 7723b63a66b..273adbad7cf 100644
--- a/apps/encryption/lib/Crypto/Crypt.php
+++ b/apps/encryption/lib/Crypto/Crypt.php
@@ -32,6 +32,7 @@ namespace OCA\Encryption\Crypto;
 
 use OC\Encryption\Exceptions\DecryptionFailedException;
 use OC\Encryption\Exceptions\EncryptionFailedException;
+use OC\ServerNotAvailableException;
 use OCA\Encryption\Exceptions\MultiKeyDecryptException;
 use OCA\Encryption\Exceptions\MultiKeyEncryptException;
 use OCP\Encryption\Exceptions\GenericEncryptionException;
@@ -89,6 +90,9 @@ class Crypt {
 		'AES-128-CFB' => 16,
 	];
 
+	/** @var bool */
+	private $supportLegacy;
+
 	/**
 	 * @param ILogger $logger
 	 * @param IUserSession $userSession
@@ -101,6 +105,8 @@ class Crypt {
 		$this->config = $config;
 		$this->l = $l;
 		$this->supportedKeyFormats = ['hash', 'password'];
+
+		$this->supportLegacy = $this->config->getSystemValueBool('encryption.legacy_format_support', true);
 	}
 
 	/**
@@ -299,6 +305,10 @@ class Crypt {
 	 * @return string
 	 */
 	public function getLegacyCipher() {
+		if (!$this->supportLegacy) {
+			throw new ServerNotAvailableException('Legacy cipher is no longer supported!');
+		}
+
 		return self::LEGACY_CIPHER;
 	}
 
@@ -391,7 +401,7 @@ class Crypt {
 		if (isset($header['cipher'])) {
 			$cipher = $header['cipher'];
 		} else {
-			$cipher = self::LEGACY_CIPHER;
+			$cipher = $this->getLegacyCipher();
 		}
 
 		if (isset($header['keyFormat'])) {
@@ -570,6 +580,11 @@ class Crypt {
 		$meta = substr($catFile, -93);
 		$signaturePosition = strpos($meta, '00sig00');
 
+		// If we no longer support the legacy format then everything needs a signature
+		if (!$skipSignatureCheck && !$this->supportLegacy && $signaturePosition === false) {
+			throw new GenericEncryptionException('Missing Signature', $this->l->t('Missing Signature'));
+		}
+
 		// enforce signature for the new 'CTR' ciphers
 		if (!$skipSignatureCheck && $signaturePosition === false && stripos($cipher, 'ctr') !== false) {
 			throw new GenericEncryptionException('Missing Signature', $this->l->t('Missing Signature'));
diff --git a/apps/encryption/tests/Crypto/CryptTest.php b/apps/encryption/tests/Crypto/CryptTest.php
index 6f7b0cc2765..35904632062 100644
--- a/apps/encryption/tests/Crypto/CryptTest.php
+++ b/apps/encryption/tests/Crypto/CryptTest.php
@@ -209,6 +209,9 @@ class CryptTest extends TestCase {
 	 * @dataProvider dataTestSplitMetaData
 	 */
 	public function testSplitMetaData($data, $expected) {
+		$this->config->method('getSystemValue')
+			->with('encryption_skip_signature_check', false)
+			->willReturn(true);
 		$result = self::invokePrivate($this->crypt, 'splitMetaData', [$data, 'AES-256-CFB']);
 		$this->assertTrue(is_array($result));
 		$this->assertSame(3, count($result));
@@ -233,6 +236,9 @@ class CryptTest extends TestCase {
 	 * @dataProvider dataTestHasSignature
 	 */
 	public function testHasSignature($data, $expected) {
+		$this->config->method('getSystemValue')
+			->with('encryption_skip_signature_check', false)
+			->willReturn(true);
 		$this->assertSame($expected,
 			$this->invokePrivate($this->crypt, 'hasSignature', [$data, 'AES-256-CFB'])
 		);
@@ -385,6 +391,10 @@ class CryptTest extends TestCase {
 	 * @dataProvider dataTestDecryptPrivateKey
 	 */
 	public function testDecryptPrivateKey($header, $privateKey, $expectedCipher, $isValidKey, $expected) {
+		$this->config->method('getSystemValueBool')
+			->with('encryption.legacy_format_support', true)
+			->willReturn(true);
+
 		/** @var \OCA\Encryption\Crypto\Crypt | \PHPUnit_Framework_MockObject_MockObject $crypt */
 		$crypt = $this->getMockBuilder(Crypt::class)
 			->setConstructorArgs(
diff --git a/apps/encryption/tests/Settings/AdminTest.php b/apps/encryption/tests/Settings/AdminTest.php
index 78ea6158fd2..82eed2d78a9 100644
--- a/apps/encryption/tests/Settings/AdminTest.php
+++ b/apps/encryption/tests/Settings/AdminTest.php
@@ -74,20 +74,21 @@ class AdminTest extends TestCase {
 
 	public function testGetForm() {
 		$this->config
-			->expects($this->at(0))
 			->method('getAppValue')
-			->with('encryption', 'recoveryAdminEnabled', '0')
-			->willReturn(1);
-		$this->config
-			->expects($this->at(1))
-			->method('getAppValue')
-			->with('encryption', 'encryptHomeStorage', '1')
-			->willReturn(1);
+			->will($this->returnCallback(function ($app, $key, $default) {
+				if ($app === 'encryption' && $key === 'recoveryAdminEnabled' && $default === '0') {
+					return '1';
+				}
+				if ($app === 'encryption' && $key === 'encryptHomeStorage' && $default === '1') {
+					return '1';
+				}
+				return $default;
+			}));
 		$params = [
-			'recoveryEnabled' => 1,
+			'recoveryEnabled' => '1',
 			'initStatus' => '0',
-			'encryptHomeStorage' => false,
-			'masterKeyEnabled' => false
+			'encryptHomeStorage' => true,
+			'masterKeyEnabled' => true
 		];
 		$expected = new TemplateResponse('encryption', 'settings-admin', $params, '');
 		$this->assertEquals($expected, $this->admin->getForm());