ec.js

'use strict';

const {
  ArrayPrototypeIncludes,
  ObjectKeys,
  SafeSet,
} = primordials;

const {
  ECKeyExportJob,
  KeyObjectHandle,
  SignJob,
  kCryptoJobAsync,
  kKeyTypePrivate,
  kSignJobModeSign,
  kSignJobModeVerify,
  kSigEncP1363,
} = internalBinding('crypto');

const {
  getUsagesUnion,
  hasAnyNotIn,
  jobPromise,
  normalizeHashName,
  validateKeyOps,
  kHandle,
  kKeyObject,
  kNamedCurveAliases,
} = require('internal/crypto/util');

const {
  lazyDOMException,
  promisify,
} = require('internal/util');

const {
  generateKeyPair: _generateKeyPair,
} = require('internal/crypto/keygen');

const {
  InternalCryptoKey,
  PrivateKeyObject,
  PublicKeyObject,
  createPrivateKey,
  createPublicKey,
} = require('internal/crypto/keys');

const generateKeyPair = promisify(_generateKeyPair);

function verifyAcceptableEcKeyUse(name, isPublic, usages) {
  let checkSet;
  switch (name) {
    case 'ECDH':
      checkSet = isPublic ? [] : ['deriveKey', 'deriveBits'];
      break;
    case 'ECDSA':
      checkSet = isPublic ? ['verify'] : ['sign'];
      break;
    default:
      throw lazyDOMException(
        'The algorithm is not supported', 'NotSupportedError');
  }
  if (hasAnyNotIn(usages, checkSet)) {
    throw lazyDOMException(
      `Unsupported key usage for a ${name} key`,
      'SyntaxError');
  }
}

function createECPublicKeyRaw(namedCurve, keyData) {
  const handle = new KeyObjectHandle();

  if (!handle.initECRaw(kNamedCurveAliases[namedCurve], keyData)) {
    throw lazyDOMException('Invalid keyData', 'DataError');
  }

  return new PublicKeyObject(handle);
}

async function ecGenerateKey(algorithm, extractable, keyUsages) {
  const { name, namedCurve } = algorithm;

  if (!ArrayPrototypeIncludes(ObjectKeys(kNamedCurveAliases), namedCurve)) {
    throw lazyDOMException(
      'Unrecognized namedCurve',
      'NotSupportedError');
  }

  const usageSet = new SafeSet(keyUsages);
  switch (name) {
    case 'ECDSA':
      if (hasAnyNotIn(usageSet, ['sign', 'verify'])) {
        throw lazyDOMException(
          'Unsupported key usage for an ECDSA key',
          'SyntaxError');
      }
      break;
    case 'ECDH':
      if (hasAnyNotIn(usageSet, ['deriveKey', 'deriveBits'])) {
        throw lazyDOMException(
          'Unsupported key usage for an ECDH key',
          'SyntaxError');
      }
      // Fall through
  }

  const keypair = await generateKeyPair('ec', { namedCurve }).catch((err) => {
    throw lazyDOMException(
      'The operation failed for an operation-specific reason',
      { name: 'OperationError', cause: err });
  });

  let publicUsages;
  let privateUsages;
  switch (name) {
    case 'ECDSA':
      publicUsages = getUsagesUnion(usageSet, 'verify');
      privateUsages = getUsagesUnion(usageSet, 'sign');
      break;
    case 'ECDH':
      publicUsages = [];
      privateUsages = getUsagesUnion(usageSet, 'deriveKey', 'deriveBits');
      break;
  }

  const keyAlgorithm = { name, namedCurve };

  const publicKey =
    new InternalCryptoKey(
      keypair.publicKey,
      keyAlgorithm,
      publicUsages,
      true);

  const privateKey =
    new InternalCryptoKey(
      keypair.privateKey,
      keyAlgorithm,
      privateUsages,
      extractable);

  return { publicKey, privateKey };
}

function ecExportKey(key, format) {
  return jobPromise(() => new ECKeyExportJob(
    kCryptoJobAsync,
    format,
    key[kKeyObject][kHandle]));
}

async function ecImportKey(
  format,
  keyData,
  algorithm,
  extractable,
  keyUsages) {

  const { name, namedCurve } = algorithm;

  if (!ArrayPrototypeIncludes(ObjectKeys(kNamedCurveAliases), namedCurve)) {
    throw lazyDOMException(
      'Unrecognized namedCurve',
      'NotSupportedError');
  }

  let keyObject;
  const usagesSet = new SafeSet(keyUsages);
  switch (format) {
    case 'spki': {
      verifyAcceptableEcKeyUse(name, true, usagesSet);
      try {
        keyObject = createPublicKey({
          key: keyData,
          format: 'der',
          type: 'spki',
        });
      } catch (err) {
        throw lazyDOMException(
          'Invalid keyData', { name: 'DataError', cause: err });
      }
      break;
    }
    case 'pkcs8': {
      verifyAcceptableEcKeyUse(name, false, usagesSet);
      try {
        keyObject = createPrivateKey({
          key: keyData,
          format: 'der',
          type: 'pkcs8',
        });
      } catch (err) {
        throw lazyDOMException(
          'Invalid keyData', { name: 'DataError', cause: err });
      }
      break;
    }
    case 'jwk': {
      if (!keyData.kty)
        throw lazyDOMException('Invalid keyData', 'DataError');
      if (keyData.kty !== 'EC')
        throw lazyDOMException('Invalid JWK "kty" Parameter', 'DataError');
      if (keyData.crv !== namedCurve)
        throw lazyDOMException(
          'JWK "crv" does not match the requested algorithm',
          'DataError');

      verifyAcceptableEcKeyUse(
        name,
        keyData.d === undefined,
        usagesSet);

      if (usagesSet.size > 0 && keyData.use !== undefined) {
        const checkUse = name === 'ECDH' ? 'enc' : 'sig';
        if (keyData.use !== checkUse)
          throw lazyDOMException('Invalid JWK "use" Parameter', 'DataError');
      }

      validateKeyOps(keyData.key_ops, usagesSet);

      if (keyData.ext !== undefined &&
          keyData.ext === false &&
          extractable === true) {
        throw lazyDOMException(
          'JWK "ext" Parameter and extractable mismatch',
          'DataError');
      }

      if (algorithm.name === 'ECDSA' && keyData.alg !== undefined) {
        let algNamedCurve;
        switch (keyData.alg) {
          case 'ES256': algNamedCurve = 'P-256'; break;
          case 'ES384': algNamedCurve = 'P-384'; break;
          case 'ES512': algNamedCurve = 'P-521'; break;
        }
        if (algNamedCurve !== namedCurve)
          throw lazyDOMException(
            'JWK "alg" does not match the requested algorithm',
            'DataError');
      }

      const handle = new KeyObjectHandle();
      const type = handle.initJwk(keyData, namedCurve);
      if (type === undefined)
        throw lazyDOMException('Invalid JWK', 'DataError');
      keyObject = type === kKeyTypePrivate ?
        new PrivateKeyObject(handle) :
        new PublicKeyObject(handle);
      break;
    }
    case 'raw': {
      verifyAcceptableEcKeyUse(name, true, usagesSet);
      keyObject = createECPublicKeyRaw(namedCurve, keyData);
      break;
    }
  }

  switch (algorithm.name) {
    case 'ECDSA':
      // Fall through
    case 'ECDH':
      if (keyObject.asymmetricKeyType !== 'ec')
        throw lazyDOMException('Invalid key type', 'DataError');
      break;
  }

  const {
    namedCurve: checkNamedCurve,
  } = keyObject[kHandle].keyDetail({});
  if (kNamedCurveAliases[namedCurve] !== checkNamedCurve)
    throw lazyDOMException('Named curve mismatch', 'DataError');

  return new InternalCryptoKey(
    keyObject,
    { name, namedCurve },
    keyUsages,
    extractable);
}

function ecdsaSignVerify(key, data, { name, hash }, signature) {
  const mode = signature === undefined ? kSignJobModeSign : kSignJobModeVerify;
  const type = mode === kSignJobModeSign ? 'private' : 'public';

  if (key.type !== type)
    throw lazyDOMException(`Key must be a ${type} key`, 'InvalidAccessError');

  const hashname = normalizeHashName(hash.name);

  return jobPromise(() => new SignJob(
    kCryptoJobAsync,
    mode,
    key[kKeyObject][kHandle],
    undefined,
    undefined,
    undefined,
    data,
    hashname,
    undefined,  // Salt length, not used with ECDSA
    undefined,  // PSS Padding, not used with ECDSA
    kSigEncP1363,
    signature));
}

module.exports = {
  ecExportKey,
  ecImportKey,
  ecGenerateKey,
  ecdsaSignVerify,
};