device/fido/authenticator_get_assertion_response.h

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef DEVICE_FIDO_AUTHENTICATOR_GET_ASSERTION_RESPONSE_H_
#define DEVICE_FIDO_AUTHENTICATOR_GET_ASSERTION_RESPONSE_H_

#include <stdint.h>

#include <array>
#include <vector>

#include "base/component_export.h"
#include "device/fido/authenticator_data.h"
#include "device/fido/fido_constants.h"
#include "device/fido/large_blob.h"
#include "device/fido/public_key_credential_descriptor.h"
#include "device/fido/public_key_credential_user_entity.h"
#include "third_party/abseil-cpp/absl/types/optional.h"

namespace device {

// Represents response from authenticators for AuthenticatorGetAssertion and
// AuthenticatorGetNextAssertion requests.
// https://fidoalliance.org/specs/fido-v2.0-rd-20170927/fido-client-to-authenticator-protocol-v2.0-rd-20170927.html#authenticatorGetAssertion
class COMPONENT_EXPORT(DEVICE_FIDO) AuthenticatorGetAssertionResponse {
 public:
  AuthenticatorGetAssertionResponse(const AuthenticatorGetAssertionResponse&) =
      delete;
  AuthenticatorGetAssertionResponse& operator=(
      const AuthenticatorGetAssertionResponse&) = delete;

  static absl::optional<AuthenticatorGetAssertionResponse>
  CreateFromU2fSignResponse(
      base::span<const uint8_t, kRpIdHashLength> relying_party_id_hash,
      base::span<const uint8_t> u2f_data,
      base::span<const uint8_t> key_handle);

  AuthenticatorGetAssertionResponse(AuthenticatorData authenticator_data,
                                    std::vector<uint8_t> signature);
  AuthenticatorGetAssertionResponse(AuthenticatorGetAssertionResponse&& that);
  AuthenticatorGetAssertionResponse& operator=(
      AuthenticatorGetAssertionResponse&& other);
  ~AuthenticatorGetAssertionResponse();

  AuthenticatorData authenticator_data;
  absl::optional<PublicKeyCredentialDescriptor> credential;
  std::vector<uint8_t> signature;
  absl::optional<PublicKeyCredentialUserEntity> user_entity;
  absl::optional<uint8_t> num_credentials;

  // hmac-secret contains the output of the hmac-secret or prf extension. The
  // values have already been decrypted.
  absl::optional<std::vector<uint8_t>> hmac_secret;

  // hmac_secret_not_evaluated will be true in cases where the
  // |FidoAuthenticator| was unable to process the extension, even though it
  // supports hmac_secret in general. This is intended for a case of Windows,
  // where some versions of webauthn.dll can only express the extension for
  // makeCredential, not getAssertion.
  bool hmac_secret_not_evaluated = false;

  // The large blob key associated to the credential. This value is only
  // returned if the assertion request contains the largeBlobKey extension on a
  // capable authenticator and the credential has an associated large blob key.
  absl::optional<std::array<uint8_t, kLargeBlobKeyLength>> large_blob_key;

  // user_selected indicates that the authenticator has a UI and has already
  // shown the user an account chooser for the empty-allowList request.
  bool user_selected = false;

  // The large blob associated with the credential.
  absl::optional<std::vector<uint8_t>> large_blob;

  // Whether a large blob was successfully written as part of this GetAssertion
  // request.
  bool large_blob_written = false;

  // Contains the compressed largeBlob data when the extension form is used.
  // This will be decompressed during processing and used to populate
  // `large_blob`.
  absl::optional<LargeBlob> large_blob_extension;

  // The transport used to generate this response. This is unknown when using
  // the Windows WebAuthn API.
  absl::optional<FidoTransportProtocol> transport_used;

  // device_public_key_signature contains the optional signature from the
  // device-bound key. See
  // https://github.com/fido-alliance/fido-2-specs/pull/1346
  absl::optional<std::vector<uint8_t>> device_public_key_signature;
};

}  // namespace device

#endif  // DEVICE_FIDO_AUTHENTICATOR_GET_ASSERTION_RESPONSE_H_