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fix(token): Implement locking for token refresh #1277

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Merged
julien-nc merged 1 commit into from
Dec 18, 2025
Merged

fix(token): Implement locking for token refresh #1277

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74 changes: 56 additions & 18 deletions lib/Service/TokenService.php
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,8 @@
use OCP\ISession;
use OCP\IURLGenerator;
use OCP\IUserSession;
use OCP\Lock\ILockingProvider;
use OCP\Lock\LockedException;
use OCP\PreConditionNotMetException;
use OCP\Security\ICrypto;
use OCP\Session\Exceptions\SessionNotAvailableException;
Expand All @@ -45,6 +47,7 @@
class TokenService {

private const SESSION_TOKEN_KEY = Application::APP_ID . '-user-token';
private const REFRESH_LOCK_KEY = Application::APP_ID . '-lock-key';

private IClient $client;

Expand All @@ -63,8 +66,8 @@ public function __construct(
private IAppManager $appManager,
private DiscoveryService $discoveryService,
private ProviderMapper $providerMapper,
private ILockingProvider $lockingProvider,
) {

}

public function storeToken(array $tokenData): Token {
Expand Down Expand Up @@ -192,18 +195,56 @@ public function reauthenticate(int $providerId) {
* @throws MultipleObjectsReturnedException
*/
public function refresh(Token $token): Token {
$oidcProvider = $this->providerMapper->getProvider($token->getProviderId());
$discovery = $this->discoveryService->obtainDiscovery($oidcProvider);
$lockKey = self::REFRESH_LOCK_KEY . '_' . $this->session->getId();

// Retry loop to acquire lock with timeout
$maxRetries = 50; // 5 seconds total (50 × 100ms)
$retryCount = 0;
$lockAcquired = false;

while (!$lockAcquired && $retryCount < $maxRetries) {
try {
$this->lockingProvider->acquireLock($lockKey, ILockingProvider::LOCK_EXCLUSIVE);
$lockAcquired = true;
$this->logger->debug('[TokenService] Acquired lock for token refresh');
} catch (LockedException $e) {
// Another request is refreshing, wait and retry
$retryCount++;
if ($retryCount >= $maxRetries) {
$this->logger->warning('[TokenService] Failed to acquire lock after retries, returning old token');
return $token;
}
usleep(100000); // 100ms between retries
}
}

try {
// Double-check: the token might have been refreshed:
// * while we were waiting for the lock (another request held it)
// * OR in another process between the moment this process checked
// the token expiration and the moment it attempted to acquire the lock
$sessionData = $this->session->get(self::SESSION_TOKEN_KEY);
if ($sessionData) {
$currentToken = new Token(json_decode($sessionData, true, 512, JSON_THROW_ON_ERROR));
if (!$currentToken->isExpired()) {
$this->logger->debug('[TokenService] Token already refreshed by another request');
return $currentToken;
}
}

// Token still expired, proceed with refresh
$oidcProvider = $this->providerMapper->getProvider($token->getProviderId());
$discovery = $this->discoveryService->obtainDiscovery($oidcProvider);

$clientSecret = $oidcProvider->getClientSecret();
if ($clientSecret !== '') {
try {
$clientSecret = $this->crypto->decrypt($clientSecret);
} catch (\Exception $e) {
$this->logger->error('[TokenService] Failed to decrypt oidc client secret to refresh the token');
$this->logger->error('[TokenService] Failed to decrypt oidc client secret');
}
}

$this->logger->debug('[TokenService] Refreshing the token: ' . $discovery['token_endpoint']);
$body = $this->clientService->post(
$discovery['token_endpoint'],
Expand All @@ -214,25 +255,24 @@ public function refresh(Token $token): Token {
'refresh_token' => $token->getRefreshToken(),
]
);
$this->logger->debug('[TokenService] Token refresh request params', [
'client_id' => $oidcProvider->getClientId(),
// 'client_secret' => $clientSecret,
'grant_type' => 'refresh_token',
// 'refresh_token' => $token->getRefreshToken(),
]);

$bodyArray = json_decode(trim($body), true, 512, JSON_THROW_ON_ERROR);
$this->logger->debug('[TokenService] ---- Refresh token success');
return $this->storeToken(
array_merge(
$bodyArray,
['provider_id' => $token->getProviderId()],
)
array_merge($bodyArray, ['provider_id' => $token->getProviderId()])
);
} catch (\Exception $e) {
$this->logger->error('[TokenService] Failed to refresh token ', ['exception' => $e]);
// Failed to refresh, return old token which will be retried or otherwise timeout if expired
$this->logger->error('[TokenService] Failed to refresh token', ['exception' => $e]);
return $token;
} finally {
if ($lockAcquired) {
try {
$this->lockingProvider->releaseLock($lockKey, ILockingProvider::LOCK_EXCLUSIVE);
$this->logger->debug('[TokenService] Released lock for token refresh');
} catch (\Exception $e) {
$this->logger->error('[TokenService] Failed to release lock', ['exception' => $e]);
}
}
}
}

Expand Down Expand Up @@ -316,9 +356,7 @@ public function getExchangedToken(string $targetAudience, array $extraScopes = [
);
$this->logger->debug('[TokenService] Token exchange request params', [
'client_id' => $oidcProvider->getClientId(),
// 'client_secret' => $clientSecret,
'grant_type' => 'urn:ietf:params:oauth:grant-type:token-exchange',
// 'subject_token' => $loginToken->getAccessToken(),
'subject_token_type' => 'urn:ietf:params:oauth:token-type:access_token',
'requested_token_type' => 'urn:ietf:params:oauth:token-type:refresh_token',
'audience' => $targetAudience,
Expand Down
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