Source/WebKit/UIProcess/WebAuthentication/fido/CtapAuthenticator.cpp

/*
 * Copyright (C) 2018 Apple Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions
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 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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#include "config.h"
#include "CtapAuthenticator.h"

#if ENABLE(WEB_AUTHN)

#include "CtapDriver.h"
#include "CtapHidDriver.h"
#include "U2fAuthenticator.h"
#include <WebCore/DeviceRequestConverter.h>
#include <WebCore/DeviceResponseConverter.h>
#include <WebCore/ExceptionData.h>
#include <WebCore/U2fCommandConstructor.h>
#include <wtf/RunLoop.h>
#include <wtf/text/StringConcatenateNumbers.h>

namespace WebKit {
using namespace WebCore;
using namespace fido;

CtapAuthenticator::CtapAuthenticator(std::unique_ptr<CtapDriver>&& driver, AuthenticatorGetInfoResponse&& info)
    : FidoAuthenticator(WTFMove(driver))
    , m_info(WTFMove(info))
{
}

void CtapAuthenticator::makeCredential()
{
    ASSERT(!m_isDowngraded);
    if (processGoogleLegacyAppIdSupportExtension())
        return;
    auto cborCmd = encodeMakeCredenitalRequestAsCBOR(requestData().hash, WTF::get<PublicKeyCredentialCreationOptions>(requestData().options), m_info.options().userVerificationAvailability());
    driver().transact(WTFMove(cborCmd), [weakThis = makeWeakPtr(*this)](Vector<uint8_t>&& data) {
        ASSERT(RunLoop::isMain());
        if (!weakThis)
            return;
        weakThis->continueMakeCredentialAfterResponseReceived(WTFMove(data));
    });
}

void CtapAuthenticator::continueMakeCredentialAfterResponseReceived(Vector<uint8_t>&& data) const
{
    auto response = readCTAPMakeCredentialResponse(data, WTF::get<PublicKeyCredentialCreationOptions>(requestData().options).attestation);
    if (!response) {
        auto error = getResponseCode(data);
        if (error == CtapDeviceResponseCode::kCtap2ErrCredentialExcluded)
            receiveRespond(ExceptionData { InvalidStateError, "At least one credential matches an entry of the excludeCredentials list in the authenticator."_s });
        else
            receiveRespond(ExceptionData { UnknownError, makeString("Unknown internal error. Error code: ", static_cast<uint8_t>(error)) });
        return;
    }
    receiveRespond(WTFMove(*response));
}

void CtapAuthenticator::getAssertion()
{
    ASSERT(!m_isDowngraded);
    auto cborCmd = encodeGetAssertionRequestAsCBOR(requestData().hash, WTF::get<PublicKeyCredentialRequestOptions>(requestData().options), m_info.options().userVerificationAvailability());
    driver().transact(WTFMove(cborCmd), [weakThis = makeWeakPtr(*this)](Vector<uint8_t>&& data) {
        ASSERT(RunLoop::isMain());
        if (!weakThis)
            return;
        weakThis->continueGetAssertionAfterResponseReceived(WTFMove(data));
    });
}

void CtapAuthenticator::continueGetAssertionAfterResponseReceived(Vector<uint8_t>&& data)
{
    auto response = readCTAPGetAssertionResponse(data);
    if (!response) {
        auto error = getResponseCode(data);
        if (error != CtapDeviceResponseCode::kCtap2ErrInvalidCBOR && tryDowngrade())
            return;
        if (error == CtapDeviceResponseCode::kCtap2ErrNoCredentials && observer())
            observer()->authenticatorStatusUpdated(WebAuthenticationStatus::NoCredentialsFound);
        receiveRespond(ExceptionData { UnknownError, makeString("Unknown internal error. Error code: ", static_cast<uint8_t>(error)) });
        return;
    }
    receiveRespond(WTFMove(*response));
}

bool CtapAuthenticator::tryDowngrade()
{
    if (m_info.versions().find(ProtocolVersion::kU2f) == m_info.versions().end())
        return false;
    if (!isConvertibleToU2fSignCommand(WTF::get<PublicKeyCredentialRequestOptions>(requestData().options)))
        return false;
    if (!observer())
        return false;

    m_isDowngraded = true;
    driver().setProtocol(ProtocolVersion::kU2f);
    observer()->downgrade(this, U2fAuthenticator::create(releaseDriver()));
    return true;
}

// Only U2F protocol is supported for Google legacy AppID support.
bool CtapAuthenticator::processGoogleLegacyAppIdSupportExtension()
{
    // AuthenticatorCoordinator::create should always set it.
    auto& extensions = WTF::get<PublicKeyCredentialCreationOptions>(requestData().options).extensions;
    ASSERT(!!extensions);
    if (extensions->googleLegacyAppidSupport)
        tryDowngrade();
    return extensions->googleLegacyAppidSupport;
}

} // namespace WebKit

#endif // ENABLE(WEB_AUTHN)