fix(signed-request): use share owner on reshare

Signed-off-by: Maxence Lange <maxence@artificial-owl.com>

apps/cloud_federation_api/lib/Controller/RequestHandlerController.php

@@ -441,7 +441,7 @@ class RequestHandlerController extends Controller {
 				return;
 			}
 		} elseif ($instance !== $signedRequest->getOrigin()) {
-			throw new IncomingRequestException('remote instance {instance} not linked to origin {origin}', ['instance' => $instance, 'origin' => $signedRequest->getOrigin()]);
+			throw new IncomingRequestException('remote instance ' . $instance . ' not linked to origin ' . $signedRequest->getOrigin());
 		}
 	}
 

apps/federatedfilesharing/lib/OCM/CloudFederationProviderFiles.php

@@ -766,10 +766,16 @@ class CloudFederationProviderFiles implements ISignedCloudFederationProvider {
 		$provider = $this->shareProviderFactory->getProviderForType(IShare::TYPE_REMOTE);
 		try {
 			$share = $provider->getShareByToken($sharedSecret);
-		} catch (ShareNotFound $e) {
+		} catch (ShareNotFound) {
 			return '';
 		}
 
-		return $share->getSharedWith();
+		// if uid_owner is a local account, the request comes from the recipient
+		// if not, request comes from the instance that owns the share and recipient is the re-sharer
+		if ($this->userManager->get($share->getShareOwner()) !== null) {
+			return $share->getSharedWith();
+		} else {
+			return $share->getShareOwner();
+		}
 	}
 }