Make 2FA providers stateful

This adds persistence to the Nextcloud server 2FA logic so that the server
knows which 2FA providers are enabled for a specific user at any time, even
when the provider is not available.

The `IStatefulProvider` interface was added as tagging interface for providers
that are compatible with this new API.

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

1 files changed, 110 insertions, 0 deletions

diff --git a/core/Command/TwoFactorAuth/State.php b/core/Command/TwoFactorAuth/State.php
new file mode 100644
index 00000000000..076e2211a12
--- /dev/null
+++ b/core/Command/TwoFactorAuth/State.php
@@ -0,0 +1,110 @@
+<?php
+
+declare(strict_types = 1);
+
+/**
+ * @copyright 2018 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2018 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @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 OC\Core\Command\TwoFactorAuth;
+
+use OC\Core\Command\Base;
+use OCP\Authentication\TwoFactorAuth\IRegistry;
+use OCP\IUserManager;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+class State extends Base {
+
+	/** @var IRegistry */
+	private $registry;
+
+	/** @var IUserManager */
+	private $userManager;
+
+	public function __construct(IRegistry $registry, IUserManager $userManager) {
+		parent::__construct('twofactorauth:state');
+
+		$this->registry = $registry;
+		$this->userManager = $userManager;
+	}
+
+	protected function configure() {
+		parent::configure();
+
+		$this->setName('twofactorauth:state');
+		$this->setDescription('Get the two-factor authentication (2FA) state of a user');
+		$this->addArgument('uid', InputArgument::REQUIRED);
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output) {
+		$uid = $input->getArgument('uid');
+		$user = $this->userManager->get($uid);
+		if (is_null($user)) {
+			$output->writeln("<error>Invalid UID</error>");
+			return;
+		}
+
+		$providerStates = $this->registry->getProviderStates($user);
+		$filtered = $this->filterEnabledDisabledUnknownProviders($providerStates);
+		list ($enabled, $disabled) = $filtered;
+
+		if (!empty($enabled)) {
+			$output->writeln("Two-factor authentication is enabled for user $uid");
+		} else {
+			$output->writeln("Two-factor authentication is not enabled for user $uid");
+		}
+
+		$output->writeln("");
+		$this->printProviders("Enabled providers", $enabled, $output);
+		$this->printProviders("Disabled providers", $disabled, $output);
+	}
+
+	private function filterEnabledDisabledUnknownProviders(array $providerStates): array {
+		$enabled = [];
+		$disabled = [];
+
+		foreach ($providerStates as $providerId => $isEnabled) {
+			if ($isEnabled) {
+				$enabled[] = $providerId;
+			} else {
+				$disabled[] = $providerId;
+			}
+		}
+
+		return [$enabled, $disabled];
+	}
+
+	private function printProviders(string $title, array $providers,
+		OutputInterface $output) {
+		if (empty($providers)) {
+			// Ignore and don't print anything
+			return;
+		}
+
+		$output->writeln($title . ":");
+		foreach ($providers as $provider) {
+			$output->writeln("- " . $provider);
+		}
+	}
+
+}