2 files changed, 172 insertions, 0 deletions
diff --git a/lib/private/Security/VerificationToken/CleanUpJob.php b/lib/private/Security/VerificationToken/CleanUpJob.php
new file mode 100644
index 00000000000..ba8f4352f80
--- /dev/null
+++ b/lib/private/Security/VerificationToken/CleanUpJob.php
@@ -0,0 +1,63 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2021 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OC\Security\VerificationToken;
+
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\BackgroundJob\IJobList;
+use OCP\BackgroundJob\Job;
+use OCP\IConfig;
+use OCP\IUserManager;
+use OCP\Security\VerificationToken\InvalidTokenException;
+use OCP\Security\VerificationToken\IVerificationToken;
+
+class CleanUpJob extends Job {
+	protected ?int $runNotBefore = null;
+	protected ?string $userId = null;
+	protected ?string $subject = null;
+	protected ?string $pwdPrefix = null;
+
+	public function __construct(
+		ITimeFactory $time,
+		private IConfig $config,
+		private IVerificationToken $verificationToken,
+		private IUserManager $userManager,
+	) {
+		parent::__construct($time);
+	}
+
+	public function setArgument($argument): void {
+		parent::setArgument($argument);
+		$args = \json_decode($argument, true);
+		$this->userId = (string)$args['userId'];
+		$this->subject = (string)$args['subject'];
+		$this->pwdPrefix = (string)$args['pp'];
+		$this->runNotBefore = (int)$args['notBefore'];
+	}
+
+	protected function run($argument): void {
+		try {
+			$user = $this->userManager->get($this->userId);
+			if ($user === null) {
+				return;
+			}
+			$this->verificationToken->check('irrelevant', $user, $this->subject, $this->pwdPrefix);
+		} catch (InvalidTokenException $e) {
+			if ($e->getCode() === InvalidTokenException::TOKEN_EXPIRED) {
+				// make sure to only remove expired tokens
+				$this->config->deleteUserValue($this->userId, 'core', $this->subject);
+			}
+		}
+	}
+
+	public function start(IJobList $jobList): void {
+		if ($this->time->getTime() >= $this->runNotBefore) {
+			$jobList->remove($this, $this->argument);
+			parent::start($jobList);
+		}
+	}
+}
diff --git a/lib/private/Security/VerificationToken/VerificationToken.php b/lib/private/Security/VerificationToken/VerificationToken.php
new file mode 100644
index 00000000000..89f45180359
--- /dev/null
+++ b/lib/private/Security/VerificationToken/VerificationToken.php
@@ -0,0 +1,109 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2021 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OC\Security\VerificationToken;
+
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\BackgroundJob\IJobList;
+use OCP\IConfig;
+use OCP\IUser;
+use OCP\Security\ICrypto;
+use OCP\Security\ISecureRandom;
+use OCP\Security\VerificationToken\InvalidTokenException;
+use OCP\Security\VerificationToken\IVerificationToken;
+use function json_encode;
+
+class VerificationToken implements IVerificationToken {
+	protected const TOKEN_LIFETIME = 60 * 60 * 24 * 7;
+
+	public function __construct(
+		private IConfig $config,
+		private ICrypto $crypto,
+		private ITimeFactory $timeFactory,
+		private ISecureRandom $secureRandom,
+		private IJobList $jobList,
+	) {
+	}
+
+	/**
+	 * @throws InvalidTokenException
+	 */
+	protected function throwInvalidTokenException(int $code): void {
+		throw new InvalidTokenException($code);
+	}
+
+	public function check(
+		string $token,
+		?IUser $user,
+		string $subject,
+		string $passwordPrefix = '',
+		bool $expiresWithLogin = false,
+	): void {
+		if ($user === null || !$user->isEnabled()) {
+			$this->throwInvalidTokenException(InvalidTokenException::USER_UNKNOWN);
+		}
+
+		$encryptedToken = $this->config->getUserValue($user->getUID(), 'core', $subject, null);
+		if ($encryptedToken === null) {
+			$this->throwInvalidTokenException(InvalidTokenException::TOKEN_NOT_FOUND);
+		}
+
+		try {
+			$decryptedToken = $this->crypto->decrypt($encryptedToken, $passwordPrefix . $this->config->getSystemValueString('secret'));
+		} catch (\Exception $e) {
+			// Retry with empty secret as a fallback for instances where the secret might not have been set by accident
+			try {
+				$decryptedToken = $this->crypto->decrypt($encryptedToken, $passwordPrefix);
+			} catch (\Exception $e2) {
+				$this->throwInvalidTokenException(InvalidTokenException::TOKEN_DECRYPTION_ERROR);
+			}
+		}
+
+		$splitToken = explode(':', $decryptedToken);
+		if (count($splitToken) !== 2) {
+			$this->throwInvalidTokenException(InvalidTokenException::TOKEN_INVALID_FORMAT);
+		}
+
+		if ($splitToken[0] < ($this->timeFactory->getTime() - self::TOKEN_LIFETIME)
+			|| ($expiresWithLogin && $user->getLastLogin() > $splitToken[0])) {
+			$this->throwInvalidTokenException(InvalidTokenException::TOKEN_EXPIRED);
+		}
+
+		if (!hash_equals($splitToken[1], $token)) {
+			$this->throwInvalidTokenException(InvalidTokenException::TOKEN_MISMATCH);
+		}
+	}
+
+	public function create(
+		IUser $user,
+		string $subject,
+		string $passwordPrefix = '',
+	): string {
+		$token = $this->secureRandom->generate(
+			21,
+			ISecureRandom::CHAR_DIGITS
+			. ISecureRandom::CHAR_LOWER
+			. ISecureRandom::CHAR_UPPER
+		);
+		$tokenValue = $this->timeFactory->getTime() . ':' . $token;
+		$encryptedValue = $this->crypto->encrypt($tokenValue, $passwordPrefix . $this->config->getSystemValueString('secret'));
+		$this->config->setUserValue($user->getUID(), 'core', $subject, $encryptedValue);
+		$jobArgs = json_encode([
+			'userId' => $user->getUID(),
+			'subject' => $subject,
+			'pp' => $passwordPrefix,
+			'notBefore' => $this->timeFactory->getTime() + self::TOKEN_LIFETIME * 2, // multiply to provide a grace period
+		]);
+		$this->jobList->add(CleanUpJob::class, $jobArgs);
+
+		return $token;
+	}
+
+	public function delete(string $token, IUser $user, string $subject): void {
+		$this->config->deleteUserValue($user->getUID(), 'core', $subject);
+	}
+}