1 files changed, 261 insertions, 0 deletions
diff --git a/apps/encryption/lib/Recovery.php b/apps/encryption/lib/Recovery.php
new file mode 100644
index 00000000000..38e78f5e822
--- /dev/null
+++ b/apps/encryption/lib/Recovery.php
@@ -0,0 +1,261 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2019-2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-FileCopyrightText: 2016 ownCloud, Inc.
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+namespace OCA\Encryption;
+
+use OC\Files\View;
+use OCA\Encryption\Crypto\Crypt;
+use OCP\Encryption\IFile;
+use OCP\IConfig;
+use OCP\IUser;
+use OCP\IUserSession;
+use OCP\PreConditionNotMetException;
+
+class Recovery {
+	/**
+	 * @var null|IUser
+	 */
+	protected $user;
+
+	/**
+	 * @param IUserSession $userSession
+	 * @param Crypt $crypt
+	 * @param KeyManager $keyManager
+	 * @param IConfig $config
+	 * @param IFile $file
+	 * @param View $view
+	 */
+	public function __construct(
+		IUserSession $userSession,
+		protected Crypt $crypt,
+		private KeyManager $keyManager,
+		private IConfig $config,
+		private IFile $file,
+		private View $view,
+	) {
+		$this->user = ($userSession->isLoggedIn()) ? $userSession->getUser() : null;
+	}
+
+	/**
+	 * @param string $password
+	 * @return bool
+	 */
+	public function enableAdminRecovery($password) {
+		$appConfig = $this->config;
+		$keyManager = $this->keyManager;
+
+		if (!$keyManager->recoveryKeyExists()) {
+			$keyPair = $this->crypt->createKeyPair();
+			if (!is_array($keyPair)) {
+				return false;
+			}
+
+			$this->keyManager->setRecoveryKey($password, $keyPair);
+		}
+
+		if ($keyManager->checkRecoveryPassword($password)) {
+			$appConfig->setAppValue('encryption', 'recoveryAdminEnabled', '1');
+			return true;
+		}
+
+		return false;
+	}
+
+	/**
+	 * change recovery key id
+	 *
+	 * @param string $newPassword
+	 * @param string $oldPassword
+	 * @return bool
+	 */
+	public function changeRecoveryKeyPassword($newPassword, $oldPassword) {
+		$recoveryKey = $this->keyManager->getSystemPrivateKey($this->keyManager->getRecoveryKeyId());
+		$decryptedRecoveryKey = $this->crypt->decryptPrivateKey($recoveryKey, $oldPassword);
+		if ($decryptedRecoveryKey === false) {
+			return false;
+		}
+		$encryptedRecoveryKey = $this->crypt->encryptPrivateKey($decryptedRecoveryKey, $newPassword);
+		$header = $this->crypt->generateHeader();
+		if ($encryptedRecoveryKey) {
+			$this->keyManager->setSystemPrivateKey($this->keyManager->getRecoveryKeyId(), $header . $encryptedRecoveryKey);
+			return true;
+		}
+		return false;
+	}
+
+	/**
+	 * @param string $recoveryPassword
+	 * @return bool
+	 */
+	public function disableAdminRecovery($recoveryPassword) {
+		$keyManager = $this->keyManager;
+
+		if ($keyManager->checkRecoveryPassword($recoveryPassword)) {
+			// Set recoveryAdmin as disabled
+			$this->config->setAppValue('encryption', 'recoveryAdminEnabled', '0');
+			return true;
+		}
+		return false;
+	}
+
+	/**
+	 * check if recovery is enabled for user
+	 *
+	 * @param string $user if no user is given we check the current logged-in user
+	 *
+	 * @return bool
+	 */
+	public function isRecoveryEnabledForUser($user = '') {
+		$uid = $user === '' ? $this->user->getUID() : $user;
+		$recoveryMode = $this->config->getUserValue($uid,
+			'encryption',
+			'recoveryEnabled',
+			0);
+
+		return ($recoveryMode === '1');
+	}
+
+	/**
+	 * check if recovery is key is enabled by the administrator
+	 *
+	 * @return bool
+	 */
+	public function isRecoveryKeyEnabled() {
+		$enabled = $this->config->getAppValue('encryption', 'recoveryAdminEnabled', '0');
+
+		return ($enabled === '1');
+	}
+
+	/**
+	 * @param string $value
+	 * @return bool
+	 */
+	public function setRecoveryForUser($value) {
+		try {
+			$this->config->setUserValue($this->user->getUID(),
+				'encryption',
+				'recoveryEnabled',
+				$value);
+
+			if ($value === '1') {
+				$this->addRecoveryKeys('/' . $this->user->getUID() . '/files/');
+			} else {
+				$this->removeRecoveryKeys('/' . $this->user->getUID() . '/files/');
+			}
+
+			return true;
+		} catch (PreConditionNotMetException $e) {
+			return false;
+		}
+	}
+
+	/**
+	 * add recovery key to all encrypted files
+	 */
+	private function addRecoveryKeys(string $path): void {
+		$dirContent = $this->view->getDirectoryContent($path);
+		foreach ($dirContent as $item) {
+			$filePath = $item->getPath();
+			if ($item['type'] === 'dir') {
+				$this->addRecoveryKeys($filePath . '/');
+			} else {
+				$fileKey = $this->keyManager->getFileKey($filePath, $this->user->getUID(), null);
+				if (!empty($fileKey)) {
+					$accessList = $this->file->getAccessList($filePath);
+					$publicKeys = [];
+					foreach ($accessList['users'] as $uid) {
+						$publicKeys[$uid] = $this->keyManager->getPublicKey($uid);
+					}
+
+					$publicKeys = $this->keyManager->addSystemKeys($accessList, $publicKeys, $this->user->getUID());
+
+					$shareKeys = $this->crypt->multiKeyEncrypt($fileKey, $publicKeys);
+					$this->keyManager->deleteLegacyFileKey($filePath);
+					foreach ($shareKeys as $uid => $keyFile) {
+						$this->keyManager->setShareKey($filePath, $uid, $keyFile);
+					}
+				}
+			}
+		}
+	}
+
+	/**
+	 * remove recovery key to all encrypted files
+	 */
+	private function removeRecoveryKeys(string $path): void {
+		$dirContent = $this->view->getDirectoryContent($path);
+		foreach ($dirContent as $item) {
+			$filePath = $item->getPath();
+			if ($item['type'] === 'dir') {
+				$this->removeRecoveryKeys($filePath . '/');
+			} else {
+				$this->keyManager->deleteShareKey($filePath, $this->keyManager->getRecoveryKeyId());
+			}
+		}
+	}
+
+	/**
+	 * recover users files with the recovery key
+	 */
+	public function recoverUsersFiles(string $recoveryPassword, string $user): void {
+		$encryptedKey = $this->keyManager->getSystemPrivateKey($this->keyManager->getRecoveryKeyId());
+
+		$privateKey = $this->crypt->decryptPrivateKey($encryptedKey, $recoveryPassword);
+		if ($privateKey !== false) {
+			$this->recoverAllFiles('/' . $user . '/files/', $privateKey, $user);
+		}
+	}
+
+	/**
+	 * recover users files
+	 */
+	private function recoverAllFiles(string $path, string $privateKey, string $uid): void {
+		$dirContent = $this->view->getDirectoryContent($path);
+
+		foreach ($dirContent as $item) {
+			// Get relative path from encryption/keyfiles
+			$filePath = $item->getPath();
+			if ($this->view->is_dir($filePath)) {
+				$this->recoverAllFiles($filePath . '/', $privateKey, $uid);
+			} else {
+				$this->recoverFile($filePath, $privateKey, $uid);
+			}
+		}
+	}
+
+	/**
+	 * recover file
+	 */
+	private function recoverFile(string $path, string $privateKey, string $uid): void {
+		$encryptedFileKey = $this->keyManager->getEncryptedFileKey($path);
+		$shareKey = $this->keyManager->getShareKey($path, $this->keyManager->getRecoveryKeyId());
+
+		if ($encryptedFileKey && $shareKey && $privateKey) {
+			$fileKey = $this->crypt->multiKeyDecryptLegacy($encryptedFileKey,
+				$shareKey,
+				$privateKey);
+		} elseif ($shareKey && $privateKey) {
+			$fileKey = $this->crypt->multiKeyDecrypt($shareKey, $privateKey);
+		}
+
+		if (!empty($fileKey)) {
+			$accessList = $this->file->getAccessList($path);
+			$publicKeys = [];
+			foreach ($accessList['users'] as $user) {
+				$publicKeys[$user] = $this->keyManager->getPublicKey($user);
+			}
+
+			$publicKeys = $this->keyManager->addSystemKeys($accessList, $publicKeys, $uid);
+
+			$shareKeys = $this->crypt->multiKeyEncrypt($fileKey, $publicKeys);
+			$this->keyManager->deleteLegacyFileKey($path);
+			foreach ($shareKeys as $uid => $keyFile) {
+				$this->keyManager->setShareKey($path, $uid, $keyFile);
+			}
+		}
+	}
+}