browser/apps/desktop/src/platform/services/electron-crypto.service.ts

import { firstValueFrom } from "rxjs";

import { PinServiceAbstraction } from "@bitwarden/auth/common";
import { AccountService } from "@bitwarden/common/auth/abstractions/account.service";
import { KdfConfigService } from "@bitwarden/common/auth/abstractions/kdf-config.service";
import { InternalMasterPasswordServiceAbstraction } from "@bitwarden/common/auth/abstractions/master-password.service.abstraction";
import { CryptoFunctionService } from "@bitwarden/common/platform/abstractions/crypto-function.service";
import { EncryptService } from "@bitwarden/common/platform/abstractions/encrypt.service";
import { KeyGenerationService } from "@bitwarden/common/platform/abstractions/key-generation.service";
import { LogService } from "@bitwarden/common/platform/abstractions/log.service";
import { PlatformUtilsService } from "@bitwarden/common/platform/abstractions/platform-utils.service";
import { StateService } from "@bitwarden/common/platform/abstractions/state.service";
import { BiometricStateService } from "@bitwarden/common/platform/biometrics/biometric-state.service";
import { KeySuffixOptions } from "@bitwarden/common/platform/enums";
import { Utils } from "@bitwarden/common/platform/misc/utils";
import { SymmetricCryptoKey } from "@bitwarden/common/platform/models/domain/symmetric-crypto-key";
import { CryptoService } from "@bitwarden/common/platform/services/crypto.service";
import { StateProvider } from "@bitwarden/common/platform/state";
import { CsprngString } from "@bitwarden/common/types/csprng";
import { UserId } from "@bitwarden/common/types/guid";
import { UserKey } from "@bitwarden/common/types/key";

export class ElectronCryptoService extends CryptoService {
  constructor(
    pinService: PinServiceAbstraction,
    masterPasswordService: InternalMasterPasswordServiceAbstraction,
    keyGenerationService: KeyGenerationService,
    cryptoFunctionService: CryptoFunctionService,
    encryptService: EncryptService,
    platformUtilsService: PlatformUtilsService,
    logService: LogService,
    stateService: StateService,
    accountService: AccountService,
    stateProvider: StateProvider,
    private biometricStateService: BiometricStateService,
    kdfConfigService: KdfConfigService,
  ) {
    super(
      pinService,
      masterPasswordService,
      keyGenerationService,
      cryptoFunctionService,
      encryptService,
      platformUtilsService,
      logService,
      stateService,
      accountService,
      stateProvider,
      kdfConfigService,
    );
  }

  override async hasUserKeyStored(keySuffix: KeySuffixOptions, userId?: UserId): Promise<boolean> {
    if (keySuffix === KeySuffixOptions.Biometric) {
      return await this.stateService.hasUserKeyBiometric({ userId: userId });
    }
    return super.hasUserKeyStored(keySuffix, userId);
  }

  override async clearStoredUserKey(keySuffix: KeySuffixOptions, userId?: UserId): Promise<void> {
    if (keySuffix === KeySuffixOptions.Biometric) {
      await this.stateService.setUserKeyBiometric(null, { userId: userId });
      await this.biometricStateService.removeEncryptedClientKeyHalf(userId);
      await this.clearDeprecatedKeys(KeySuffixOptions.Biometric, userId);
      return;
    }
    // FIXME: Verify that this floating promise is intentional. If it is, add an explanatory comment and ensure there is proper error handling.
    // eslint-disable-next-line @typescript-eslint/no-floating-promises
    await super.clearStoredUserKey(keySuffix, userId);
  }

  protected override async storeAdditionalKeys(key: UserKey, userId: UserId) {
    await super.storeAdditionalKeys(key, userId);

    const storeBiometricKey = await this.shouldStoreKey(KeySuffixOptions.Biometric, userId);

    if (storeBiometricKey) {
      await this.storeBiometricKey(key, userId);
    } else {
      await this.stateService.setUserKeyBiometric(null, { userId: userId });
    }
    await this.clearDeprecatedKeys(KeySuffixOptions.Biometric, userId);
  }

  protected override async getKeyFromStorage(
    keySuffix: KeySuffixOptions,
    userId?: UserId,
  ): Promise<UserKey> {
    if (keySuffix === KeySuffixOptions.Biometric) {
      const userKey = await this.stateService.getUserKeyBiometric({ userId: userId });
      return userKey == null
        ? null
        : (new SymmetricCryptoKey(Utils.fromB64ToArray(userKey)) as UserKey);
    }
    return await super.getKeyFromStorage(keySuffix, userId);
  }

  protected async storeBiometricKey(key: UserKey, userId?: UserId): Promise<void> {
    // May resolve to null, in which case no client key have is required
    const clientEncKeyHalf = await this.getBiometricEncryptionClientKeyHalf(key, userId);
    await this.stateService.setUserKeyBiometric(
      { key: key.keyB64, clientEncKeyHalf },
      { userId: userId },
    );
  }

  protected async shouldStoreKey(keySuffix: KeySuffixOptions, userId?: UserId): Promise<boolean> {
    if (keySuffix === KeySuffixOptions.Biometric) {
      const biometricUnlockPromise =
        userId == null
          ? firstValueFrom(this.biometricStateService.biometricUnlockEnabled$)
          : this.biometricStateService.getBiometricUnlockEnabled(userId);
      const biometricUnlock = await biometricUnlockPromise;
      return biometricUnlock && this.platformUtilService.supportsSecureStorage();
    }
    return await super.shouldStoreKey(keySuffix, userId);
  }

  protected override async clearAllStoredUserKeys(userId?: UserId): Promise<void> {
    await this.clearStoredUserKey(KeySuffixOptions.Biometric, userId);
    await super.clearAllStoredUserKeys(userId);
  }

  private async getBiometricEncryptionClientKeyHalf(
    userKey: UserKey,
    userId: UserId,
  ): Promise<CsprngString | null> {
    const requireClientKeyHalf = await this.biometricStateService.getRequirePasswordOnStart(userId);
    if (!requireClientKeyHalf) {
      return null;
    }

    // Retrieve existing key half if it exists
    let biometricKey = await this.biometricStateService
      .getEncryptedClientKeyHalf(userId)
      .then((result) => result?.decrypt(null /* user encrypted */, userKey))
      .then((result) => result as CsprngString);
    if (biometricKey == null && userKey != null) {
      // Set a key half if it doesn't exist
      const keyBytes = await this.cryptoFunctionService.randomBytes(32);
      biometricKey = Utils.fromBufferToUtf8(keyBytes) as CsprngString;
      const encKey = await this.encryptService.encrypt(biometricKey, userKey);
      await this.biometricStateService.setEncryptedClientKeyHalf(encKey, userId);
    }

    return biometricKey;
  }
}