BREAKING: Use SIP-6 algorithm for state encryption (MetaMask#1055)

* Use SIP-6 algorithm for state encryption

* Make magic value non-optional

* Disallow deriving the state encryption magic value

* Fix iframe tests

* Remove unused files

* Move encryption logic to rpc-methods

* Remove unused parameter

* Move stuff back to rpc-methods

* Remove more stuff from controllers

* Revert controllers jest environment

* Improve snap_manageState test

packages/rpc-methods/jest.config.js

@@ -3,13 +3,17 @@ const deepmerge = require('deepmerge');
 const baseConfig = require('../../jest.config.base');
 
 module.exports = deepmerge(baseConfig, {
-  coveragePathIgnorePatterns: ['./src/index.ts'],
+  collectCoverageFrom: [
+    './src/**/*.ts',
+    '!./src/**/*.test.ts',
+    '!./src/**/index.ts',
+  ],
   coverageThreshold: {
     global: {
-      branches: 74.63,
-      functions: 83.33,
-      lines: 83.46,
-      statements: 82.44,
+      branches: 75.18,
+      functions: 87.5,
+      lines: 88.67,
+      statements: 88.32,
     },
   },
   testTimeout: 2500,

packages/rpc-methods/package.json

@@ -13,7 +13,7 @@
   ],
   "scripts": {
     "test": "jest && yarn posttest",
-    "posttest": "jest-it-up",
+    "posttest": "jest-it-up --margin 0.25",
     "test:ci": "yarn test",
     "lint:eslint": "eslint . --cache --ext js,ts",
     "lint:misc": "prettier '**/*.json' '**/*.md' '!CHANGELOG.md' --ignore-path ../../.gitignore",
@@ -26,6 +26,7 @@
     "publish:package": "../../scripts/publish-package.sh"
   },
   "dependencies": {
+    "@metamask/browser-passworder": "^4.0.2",
     "@metamask/key-tree": "^6.0.0",
     "@metamask/permission-controller": "^1.0.1",
     "@metamask/snaps-utils": "^0.26.2",

packages/rpc-methods/src/restricted/getBip32Entropy.test.ts

@@ -1,4 +1,5 @@
 import { SIP_6_MAGIC_VALUE, SnapCaveatType } from '@metamask/snaps-utils';
+import { TEST_SECRET_RECOVERY_PHRASE } from '@metamask/snaps-utils/test-utils';
 
 import {
   getBip32EntropyBuilder,
@@ -8,9 +9,6 @@ import {
   validateCaveatPaths,
 } from './getBip32Entropy';
 
-const TEST_SECRET_RECOVERY_PHRASE =
-  'test test test test test test test test test test test ball';
-
 describe('validateCaveatPaths', () => {
   it.each([[], null, undefined, 'foo'])(
     'throws if the value is not an array or empty',

packages/rpc-methods/src/restricted/getEntropy.test.ts

@@ -1,8 +1,7 @@
 import { PermissionType } from '@metamask/permission-controller';
 import { MOCK_SNAP_ID } from '@metamask/snaps-utils/test-utils';
 
-import { ENTROPY_VECTORS } from './__fixtures__';
-import { deriveEntropy, getEntropyBuilder } from './getEntropy';
+import { getEntropyBuilder } from './getEntropy';
 
 const TEST_SECRET_RECOVERY_PHRASE =
   'test test test test test test test test test test test ball';
@@ -36,19 +35,6 @@ describe('getEntropyBuilder', () => {
   });
 });
 
-describe('deriveEntropy', () => {
-  it.each(ENTROPY_VECTORS)(
-    'derives entropy from the given parameters',
-    async () => {
-      const { snapId, salt, entropy } = ENTROPY_VECTORS[0];
-
-      expect(
-        await deriveEntropy(snapId, TEST_SECRET_RECOVERY_PHRASE, salt ?? ''),
-      ).toStrictEqual(entropy);
-    },
-  );
-});
-
 describe('getEntropyImplementation', () => {
   it('returns the expected result', async () => {
     const getMnemonic = jest

packages/rpc-methods/src/restricted/getEntropy.ts

@@ -1,26 +1,15 @@
-import { HardenedBIP32Node, SLIP10Node } from '@metamask/key-tree';
 import {
   PermissionSpecificationBuilder,
   PermissionType,
   RestrictedMethodOptions,
   ValidPermissionSpecification,
 } from '@metamask/permission-controller';
 import { SIP_6_MAGIC_VALUE } from '@metamask/snaps-utils';
-import {
-  add0x,
-  assert,
-  assertStruct,
-  concatBytes,
-  createDataView,
-  Hex,
-  NonEmptyArray,
-  stringToBytes,
-} from '@metamask/utils';
-import { keccak_256 as keccak256 } from '@noble/hashes/sha3';
+import { assertStruct, Hex, NonEmptyArray } from '@metamask/utils';
 import { ethErrors } from 'eth-rpc-errors';
 import { Infer, literal, object, optional, string } from 'superstruct';
 
-const HARDENED_VALUE = 0x80000000;
+import { deriveEntropy } from '../utils';
 
 const targetKey = 'snap_getEntropy';
 
@@ -88,70 +77,6 @@ export type GetEntropyHooks = {
   getUnlockPromise: (shouldShowUnlockRequest: boolean) => Promise<void>;
 };
 
-/**
- * Get a BIP-32 derivation path array from a hash, which is compatible with
- * `@metamask/key-tree`. The hash is assumed to be 32 bytes long.
- *
- * @param hash - The hash to derive indices from.
- * @returns The derived indices as a {@link HardenedBIP32Node} array.
- */
-function getDerivationPathArray(hash: Uint8Array): HardenedBIP32Node[] {
-  const array: HardenedBIP32Node[] = [];
-  const view = createDataView(hash);
-
-  for (let index = 0; index < 8; index++) {
-    const uint32 = view.getUint32(index * 4);
-
-    // This is essentially `index | 0x80000000`. Because JavaScript numbers are
-    // signed, we use the bitwise unsigned right shift operator to ensure that
-    // the result is a positive number.
-    // eslint-disable-next-line no-bitwise
-    const pathIndex = (uint32 | HARDENED_VALUE) >>> 0;
-    array.push(`bip32:${pathIndex - HARDENED_VALUE}'` as const);
-  }
-
-  return array;
-}
-
-/**
- * Derive entropy from the given mnemonic phrase and salt.
- *
- * This is based on the reference implementation of
- * [SIP-6](https://metamask.github.io/SIPs/SIPS/sip-6).
- *
- * @param snapId - The snap ID to derive entropy for.
- * @param mnemonicPhrase - The mnemonic phrase to derive entropy from.
- * @param salt - The salt to use when deriving entropy.
- * @returns The derived entropy.
- */
-export async function deriveEntropy(
-  snapId: string,
-  mnemonicPhrase: string,
-  salt = '',
-): Promise<Hex> {
-  const snapIdBytes = stringToBytes(snapId);
-  const saltBytes = stringToBytes(salt);
-
-  // Get the derivation path from the snap ID.
-  const hash = keccak256(concatBytes([snapIdBytes, keccak256(saltBytes)]));
-  const computedDerivationPath = getDerivationPathArray(hash);
-
-  // Derive the private key using BIP-32.
-  const { privateKey } = await SLIP10Node.fromDerivationPath({
-    derivationPath: [
-      `bip39:${mnemonicPhrase}`,
-      `bip32:${SIP_6_MAGIC_VALUE}`,
-      ...computedDerivationPath,
-    ],
-    curve: 'secp256k1',
-  });
-
-  // This should never happen, but this keeps TypeScript happy.
-  assert(privateKey, 'Failed to derive the entropy.');
-
-  return add0x(privateKey);
-}
-
 /**
  * Builds the method implementation for `snap_getEntropy`. The implementation
  * is based on the reference implementation of
@@ -186,6 +111,11 @@ function getEntropyImplementation({
     await getUnlockPromise(true);
     const mnemonicPhrase = await getMnemonic();
 
-    return deriveEntropy(origin, mnemonicPhrase, params.salt);
+    return deriveEntropy({
+      input: origin,
+      salt: params.salt,
+      mnemonicPhrase,
+      magic: SIP_6_MAGIC_VALUE,
+    });
   };
 }