// Copyright 2020 The ChromiumOS Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CRYPTOHOME_KEYSET_MANAGEMENT_H_
#define CRYPTOHOME_KEYSET_MANAGEMENT_H_

#include <map>
#include <memory>
#include <optional>
#include <string>
#include <vector>

#include <brillo/secure_blob.h>
#include <cryptohome/proto_bindings/rpc.pb.h>
#include <cryptohome/proto_bindings/UserDataAuth.pb.h>
#include <dbus/cryptohome/dbus-constants.h>
#include <libstorage/platform/platform.h>

#include "base/files/file_path.h"
#include "cryptohome/crypto.h"
#include "cryptohome/cryptohome_metrics.h"
#include "cryptohome/error/cryptohome_error.h"
#include "cryptohome/error/cryptohome_mount_error.h"
#include "cryptohome/flatbuffer_schemas/auth_block_state.h"
#include "cryptohome/key_objects.h"
#include "cryptohome/username.h"
#include "cryptohome/vault_keyset.h"
#include "cryptohome/vault_keyset_factory.h"
#include "storage/file_system_keyset.h"

namespace cryptohome {

// The structure that stores the status of a VaultKeyset, such as whether the
// VaultKeyset is created as a backup storage.
struct VaultKeysetIntent {
  bool backup;
};

class KeysetManagement {
 public:
  using DecryptVkCallback = base::RepeatingCallback<CryptoStatus(VaultKeyset*)>;
  using EncryptVkCallback =
      base::OnceCallback<CryptohomeStatus(VaultKeyset* vk)>;

  KeysetManagement() = default;
  KeysetManagement(libstorage::Platform* platform,
                   Crypto* crypto,
                   std::unique_ptr<VaultKeysetFactory> vault_keyset_factory);
  virtual ~KeysetManagement() = default;
  KeysetManagement(const KeysetManagement&) = delete;
  KeysetManagement& operator=(const KeysetManagement&) = delete;

  // Returns a list of present keyset indices for an obfuscated username.
  // There is no guarantee the keysets are valid.
  virtual bool GetVaultKeysets(const ObfuscatedUsername& obfuscated,
                               std::vector<int>* keysets) const;

  // Returns a VaultKeyset that matches the given obfuscated username and the
  // key label. If the label is empty or if no matching keyset is found, NULL
  // will be returned.
  //
  // The caller DOES take ownership of the returned VaultKeyset pointer.
  // There is no guarantee the keyset is valid.
  virtual std::unique_ptr<VaultKeyset> GetVaultKeyset(
      const ObfuscatedUsername& obfuscated_username,
      const std::string& key_label) const;

  // Loads the vault keyset for the supplied obfuscated username and index.
  // Returns null on failure.
  virtual std::unique_ptr<VaultKeyset> LoadVaultKeysetForUser(
      const ObfuscatedUsername& obfuscated_user, int index) const;

  // This function should be called after successful authentication.
  // Populate a value to |vault_keyset|'s reset seed if it is missing, but
  // doesn't save. Returns true if the seed is added, returns false if there is
  // no need to add the reset seed, i.e if it already exists.
  virtual bool AddResetSeedIfMissing(VaultKeyset& vault_keyset);

  // Removes the keyset specified by |index| from the list for the user
  // vault identified by its |obfuscated| username.
  // The caller should check credentials if the call is user-sourced.
  // TODO(wad,ellyjones) Determine a better keyset priotization and management
  //                     scheme than just integer indices, like fingerprints.
  virtual CryptohomeStatus ForceRemoveKeyset(
      const ObfuscatedUsername& obfuscated, int index);

  // Removes only the VaultKeyset file for the given VaultKeyset object, but not
  // the metadata.
  virtual CryptohomeStatus RemoveKeysetFile(const VaultKeyset& remove_vk);

  // Removes all LE credentials for a user with |obfuscated_username|.
  virtual void RemoveLECredentials(
      const ObfuscatedUsername& obfuscated_username);

  // Get timestamp from a legacy location.
  // TODO(b/205759690, dlunev): can be removed after a stepping stone release.
  virtual base::Time GetKeysetBoundTimestamp(
      const ObfuscatedUsername& obfuscated);

  // Remove legacy location for timestamp.
  // TODO(b/205759690, dlunev): can be removed after a stepping stone release.
  virtual void CleanupPerIndexTimestampFiles(
      const ObfuscatedUsername& obfuscated);

  // Check if the vault keyset needs re-encryption.
  virtual bool ShouldReSaveKeyset(VaultKeyset* vault_keyset) const;

  // Record various metrics about all the VaultKeyset for a given user
  // obfuscated
  virtual void RecordAllVaultKeysetMetrics(
      const ObfuscatedUsername& obfuscated) const;

  // ========== KeysetManagement methods with KeyBlobs ===============

  // Resaves the vault keyset with |key_blobs|, restoring on failure.
  virtual CryptohomeStatus ReSaveKeyset(
      VaultKeyset& vault_keyset,
      KeyBlobs key_blobs,
      std::unique_ptr<AuthBlockState> auth_state) const;

  // Adds initial keyset for obfuscated username with |file_system_keyset|. Adds
  // the key data given by |key_data| and challenge credentials info given by
  // |challenge_credentials_keyset_info| to the created keyset. Wraps the keyset
  // with |key_blobs| and persists to the disk.
  virtual CryptohomeStatusOr<std::unique_ptr<VaultKeyset>> AddInitialKeyset(
      const VaultKeysetIntent& vk_intent,
      const ObfuscatedUsername& obfuscated_username,
      const KeyData& key_data,
      const std::optional<SerializedVaultKeyset_SignatureChallengeInfo>&
          challenge_credentials_keyset_info,
      const FileSystemKeyset& file_system_keyset,
      KeyBlobs key_blobs,
      std::unique_ptr<AuthBlockState> auth_state);

  // Returns decrypted with |key_blobs| keyset, or an error status with the
  // particular failure reason if none decryptable with the provided
  // |key_blobs|, |obfuscated_username| and |label|. NOTE: The LE Credential
  // Keysets are only considered when the |label| provided is non-empty
  // (b/202907485).
  virtual MountStatusOr<std::unique_ptr<VaultKeyset>> GetValidKeyset(
      const ObfuscatedUsername& obfuscated_username,
      KeyBlobs key_blobs,
      const std::optional<std::string>& label);

  // Adds a new keyset to the given |vault_keyset| and persist to
  // disk. This function assumes the user is already authenticated and their
  // old vault keyset, |old_vault_keyset| is unwrapped to initialize a new vault
  // keyset. Thus, GetValidKeyset() should be called prior to this
  // function to authenticate with the existing credentials. New keyset is
  // generated and the key data from |key_data_new| is added. New keyset is
  // persisted to disk after wrapped by |key_blobs_new| as directed by
  // |auth_state_new|. If |clobber| is true and there are no matching, labeled
  // keys, then it does nothing; if there is an identically labeled key, it will
  // overwrite it.
  virtual CryptohomeStatus AddKeyset(
      const VaultKeysetIntent& vk_intent,
      const ObfuscatedUsername& obfuscated_username_new,
      const std::string& key_label,
      const KeyData& key_data_new,
      const VaultKeyset& vault_keyset_old,
      KeyBlobs key_blobs_new,
      std::unique_ptr<AuthBlockState> auth_state_new,
      bool clobber);

  // Encrypts and saves a keyset with the given |key_blobs| at |save_path|.
  virtual CryptohomeStatus EncryptAndSaveKeyset(
      VaultKeyset& vault_keyset,
      const KeyBlobs& key_blobs,
      const AuthBlockState& auth_state,
      const base::FilePath& save_path) const;

  // Updates an existing |vault_keyset| with the |key_data_new| from new user
  // credentials. This function assumes the user is already authenticated and
  // their |vault_keyset| with an existing credentials is unwrapped. New keyset
  // is wrapped by the |key_blobs| passed, which should be derived from the new
  // credentials.
  virtual CryptohomeStatus UpdateKeysetWithKeyBlobs(
      const VaultKeysetIntent& vk_intent,
      const ObfuscatedUsername& obfuscated_username_new,
      const KeyData& key_data_new,
      const VaultKeyset& vault_keyset,
      KeyBlobs key_blobs,
      std::unique_ptr<AuthBlockState> auth_state);

 private:
  // TODO(b/205759690, dlunev): can be removed after a stepping stone release.
  base::Time GetPerIndexTimestampFileData(const ObfuscatedUsername& obfuscated,
                                          int index);

  // Records various metrics about the VaultKeyset into the VaultKeysetMetrics
  // struct.
  void RecordVaultKeysetMetrics(const VaultKeyset& vk,
                                VaultKeysetMetrics& keyset_metrics) const;

  libstorage::Platform* platform_;
  Crypto* crypto_;
  std::unique_ptr<VaultKeysetFactory> vault_keyset_factory_;
};

}  // namespace cryptohome

#endif  // CRYPTOHOME_KEYSET_MANAGEMENT_H_