Element-R: pass pickleKey in as raw key for indexeddb encryption (#12543)

* Element-R: pass pickleKey in as raw key for indexeddb encryption

Currently, we pass the `pickleKey` to the rust library for use as a passphrase
for encrypting its crypto store. The Rust libary then passes that passphrase
through 200000 rounds of PBKDF2 to generate an encryption key, which is
(deliberately) slow.

However, the pickleKey is actually 32 bytes of random data (base64-encoded). By
passing the raw key into the rust library, we can therefore save the PBKDF
operation.

Backwards-compatibility with existing sessions is maintained, because if the
rust library discovers that the store was previously encrypted with a key based
on a PBKDF, it will re-base64 and PBKDF the key we provide, thus reconstructing
the right key.

* Update src/Lifecycle.ts

Co-authored-by: Florian Duros <florianduros@element.io>

* Lifecycle-test: clean up test setup

Rely less on the unit under test for setting up the test preconditions -- not
least because we don't really want to fire up matrix clients and the like
during test setup.

* Factor out "encryptPickleKey" method

For a start it makes it easier to grok what's going on, but also I went to use
this in a test

* Improve tests for `Lifecycle.restoreFromLocalStorage`

---------

Co-authored-by: Florian Duros <florianduros@element.io>
This commit is contained in:
Richard van der Hoff 2024-06-05 09:52:28 +01:00 committed by GitHub
parent 5004456d82
commit 0a01320fca
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
6 changed files with 233 additions and 64 deletions

View file

@ -38,7 +38,7 @@ import { idbLoad, idbSave, idbDelete } from "./utils/StorageAccess";
import { ViewRoomPayload } from "./dispatcher/payloads/ViewRoomPayload";
import { IConfigOptions } from "./IConfigOptions";
import SdkConfig from "./SdkConfig";
import { buildAndEncodePickleKey, getPickleAdditionalData } from "./utils/tokens/pickling";
import { buildAndEncodePickleKey, encryptPickleKey } from "./utils/tokens/pickling";
export const SSO_HOMESERVER_URL_KEY = "mx_sso_hs_url";
export const SSO_ID_SERVER_URL_KEY = "mx_sso_is_url";
@ -378,24 +378,16 @@ export default abstract class BasePlatform {
* support storing pickle keys.
*/
public async createPickleKey(userId: string, deviceId: string): Promise<string | null> {
if (!window.crypto || !window.crypto.subtle) {
return null;
}
const crypto = window.crypto;
const randomArray = new Uint8Array(32);
crypto.getRandomValues(randomArray);
const cryptoKey = await crypto.subtle.generateKey({ name: "AES-GCM", length: 256 }, false, [
"encrypt",
"decrypt",
]);
const iv = new Uint8Array(32);
crypto.getRandomValues(iv);
const additionalData = getPickleAdditionalData(userId, deviceId);
const encrypted = await crypto.subtle.encrypt({ name: "AES-GCM", iv, additionalData }, cryptoKey, randomArray);
const data = await encryptPickleKey(randomArray, userId, deviceId);
if (data === undefined) {
// no crypto support
return null;
}
try {
await idbSave("pickleKey", [userId, deviceId], { encrypted, iv, cryptoKey });
await idbSave("pickleKey", [userId, deviceId], data);
} catch (e) {
return null;
}

View file

@ -18,12 +18,12 @@ limitations under the License.
*/
import { ReactNode } from "react";
import { createClient, MatrixClient, SSOAction, OidcTokenRefresher } from "matrix-js-sdk/src/matrix";
import { createClient, MatrixClient, SSOAction, OidcTokenRefresher, decodeBase64 } from "matrix-js-sdk/src/matrix";
import { IEncryptedPayload } from "matrix-js-sdk/src/crypto/aes";
import { QueryDict } from "matrix-js-sdk/src/utils";
import { logger } from "matrix-js-sdk/src/logger";
import { IMatrixClientCreds, MatrixClientPeg } from "./MatrixClientPeg";
import { IMatrixClientCreds, MatrixClientPeg, MatrixClientPegAssignOpts } from "./MatrixClientPeg";
import { ModuleRunner } from "./modules/ModuleRunner";
import EventIndexPeg from "./indexing/EventIndexPeg";
import createMatrixClient from "./utils/createMatrixClient";
@ -422,6 +422,7 @@ async function onSuccessfulDelegatedAuthLogin(credentials: IMatrixClientCreds):
}
type TryAgainFunction = () => void;
/**
* Display a friendly error to the user when token login or OIDC authorization fails
* @param description error description
@ -821,7 +822,23 @@ async function doSetLoggedIn(credentials: IMatrixClientCreds, clearStorageEnable
checkSessionLock();
dis.fire(Action.OnLoggedIn);
await startMatrixClient(client, /*startSyncing=*/ !softLogout);
const clientPegOpts: MatrixClientPegAssignOpts = {};
if (credentials.pickleKey) {
// The pickleKey, if provided, is probably a base64-encoded 256-bit key, so can be used for the crypto store.
if (credentials.pickleKey.length === 43) {
clientPegOpts.rustCryptoStoreKey = decodeBase64(credentials.pickleKey);
} else {
// We have some legacy pickle key. Continue using it as a password.
clientPegOpts.rustCryptoStorePassword = credentials.pickleKey;
}
}
try {
await startMatrixClient(client, /*startSyncing=*/ !softLogout, clientPegOpts);
} finally {
clientPegOpts.rustCryptoStoreKey?.fill(0);
}
return client;
}
@ -955,11 +972,16 @@ export function isLoggingOut(): boolean {
/**
* Starts the matrix client and all other react-sdk services that
* listen for events while a session is logged in.
*
* @param client the matrix client to start
* @param {boolean} startSyncing True (default) to actually start
* syncing the client.
* @param startSyncing - `true` to actually start syncing the client.
* @param clientPegOpts - Options to pass through to {@link MatrixClientPeg.start}.
*/
async function startMatrixClient(client: MatrixClient, startSyncing = true): Promise<void> {
async function startMatrixClient(
client: MatrixClient,
startSyncing: boolean,
clientPegOpts: MatrixClientPegAssignOpts,
): Promise<void> {
logger.log(`Lifecycle: Starting MatrixClient`);
// dispatch this before starting the matrix client: it's used
@ -990,10 +1012,10 @@ async function startMatrixClient(client: MatrixClient, startSyncing = true): Pro
// index (e.g. the FilePanel), therefore initialize the event index
// before the client.
await EventIndexPeg.init();
await MatrixClientPeg.start();
await MatrixClientPeg.start(clientPegOpts);
} else {
logger.warn("Caller requested only auxiliary services be started");
await MatrixClientPeg.assign();
await MatrixClientPeg.assign(clientPegOpts);
}
checkSessionLock();

View file

@ -66,6 +66,27 @@ export interface IMatrixClientCreds {
freshLogin?: boolean;
}
export interface MatrixClientPegAssignOpts {
/**
* If we are using Rust crypto, a key with which to encrypt the indexeddb.
*
* If provided, it must be exactly 32 bytes of data. If both this and
* {@link MatrixClientPegAssignOpts.rustCryptoStorePassword} are undefined,
* the store will be unencrypted.
*/
rustCryptoStoreKey?: Uint8Array;
/**
* If we are using Rust crypto, a password which will be used to derive a key to encrypt the store with.
*
* An alternative to {@link MatrixClientPegAssignOpts.rustCryptoStoreKey}. Ignored if `rustCryptoStoreKey` is set.
*
* Deriving a key from a password is (deliberately) a slow operation, so prefer to pass a `rustCryptoStoreKey`
* directly where possible.
*/
rustCryptoStorePassword?: string;
}
/**
* Holds the current instance of the `MatrixClient` to use across the codebase.
* Looking for an `MatrixClient`? Just look for the `MatrixClientPeg` on the peg
@ -94,14 +115,14 @@ export interface IMatrixClientPeg {
unset(): void;
/**
* Prepare the MatrixClient for use, including initialising the store and crypto, but do not start it
* Prepare the MatrixClient for use, including initialising the store and crypto, but do not start it.
*/
assign(): Promise<IStartClientOpts>;
assign(opts?: MatrixClientPegAssignOpts): Promise<IStartClientOpts>;
/**
* Prepare the MatrixClient for use, including initialising the store and crypto, and start it
* Prepare the MatrixClient for use, including initialising the store and crypto, and start it.
*/
start(): Promise<void>;
start(opts?: MatrixClientPegAssignOpts): Promise<void>;
/**
* If we've registered a user ID we set this to the ID of the
@ -248,7 +269,10 @@ class MatrixClientPegClass implements IMatrixClientPeg {
PlatformPeg.get()?.reload();
};
public async assign(): Promise<IStartClientOpts> {
/**
* Implementation of {@link IMatrixClientPeg.assign}.
*/
public async assign(assignOpts: MatrixClientPegAssignOpts = {}): Promise<IStartClientOpts> {
if (!this.matrixClient) {
throw new Error("createClient must be called first");
}
@ -275,7 +299,7 @@ class MatrixClientPegClass implements IMatrixClientPeg {
// try to initialise e2e on the new client
if (!SettingsStore.getValue("lowBandwidth")) {
await this.initClientCrypto();
await this.initClientCrypto(assignOpts.rustCryptoStoreKey, assignOpts.rustCryptoStorePassword);
}
const opts = utils.deepCopy(this.opts);
@ -301,8 +325,16 @@ class MatrixClientPegClass implements IMatrixClientPeg {
/**
* Attempt to initialize the crypto layer on a newly-created MatrixClient
*
* @param rustCryptoStoreKey - If we are using Rust crypto, a key with which to encrypt the indexeddb.
* If provided, it must be exactly 32 bytes of data. If both this and `rustCryptoStorePassword` are
* undefined, the store will be unencrypted.
*
* @param rustCryptoStorePassword - An alternative to `rustCryptoStoreKey`. Ignored if `rustCryptoStoreKey` is set.
* A password which will be used to derive a key to encrypt the store with. Deriving a key from a password is
* (deliberately) a slow operation, so prefer to pass a `rustCryptoStoreKey` directly where possible.
*/
private async initClientCrypto(): Promise<void> {
private async initClientCrypto(rustCryptoStoreKey?: Uint8Array, rustCryptoStorePassword?: string): Promise<void> {
if (!this.matrixClient) {
throw new Error("createClient must be called first");
}
@ -338,7 +370,13 @@ class MatrixClientPegClass implements IMatrixClientPeg {
// Now we can initialise the right crypto impl.
if (useRustCrypto) {
await this.matrixClient.initRustCrypto();
if (!rustCryptoStoreKey && !rustCryptoStorePassword) {
logger.error("Warning! Not using an encryption key for rust crypto store.");
}
await this.matrixClient.initRustCrypto({
storageKey: rustCryptoStoreKey,
storagePassword: rustCryptoStorePassword,
});
StorageManager.setCryptoInitialised(true);
// TODO: device dehydration and whathaveyou
@ -367,8 +405,11 @@ class MatrixClientPegClass implements IMatrixClientPeg {
}
}
public async start(): Promise<void> {
const opts = await this.assign();
/**
* Implementation of {@link IMatrixClientPeg.start}.
*/
public async start(assignOpts?: MatrixClientPegAssignOpts): Promise<void> {
const opts = await this.assign(assignOpts);
logger.log(`MatrixClientPeg: really starting MatrixClient`);
await this.matrixClient!.startClient(opts);

View file

@ -20,6 +20,20 @@ limitations under the License.
import { encodeUnpaddedBase64 } from "matrix-js-sdk/src/matrix";
import { logger } from "matrix-js-sdk/src/logger";
/**
* Encrypted format of a pickle key, as stored in IndexedDB.
*/
export interface EncryptedPickleKey {
/** The encrypted payload. */
encrypted?: BufferSource;
/** Initialisation vector for the encryption. */
iv?: BufferSource;
/** The encryption key which was used to encrypt the payload. */
cryptoKey?: CryptoKey;
}
/**
* Calculates the `additionalData` for the AES-GCM key used by the pickling processes. This
* additional data is *not* encrypted, but *is* authenticated. The additional data is constructed
@ -46,6 +60,32 @@ export function getPickleAdditionalData(userId: string, deviceId: string): Uint8
return additionalData;
}
/**
* Encrypt the given pickle key, ready for storage in the database.
*
* @param pickleKey - The key to be encrypted.
* @param userId - The user ID the pickle key belongs to.
* @param deviceId - The device ID the pickle key belongs to.
*
* @returns Data object ready for storing in indexeddb.
*/
export async function encryptPickleKey(
pickleKey: Uint8Array,
userId: string,
deviceId: string,
): Promise<EncryptedPickleKey | undefined> {
if (!crypto?.subtle) {
return undefined;
}
const cryptoKey = await crypto.subtle.generateKey({ name: "AES-GCM", length: 256 }, false, ["encrypt", "decrypt"]);
const iv = new Uint8Array(32);
crypto.getRandomValues(iv);
const additionalData = getPickleAdditionalData(userId, deviceId);
const encrypted = await crypto.subtle.encrypt({ name: "AES-GCM", iv, additionalData }, cryptoKey, pickleKey);
return { encrypted, iv, cryptoKey };
}
/**
* Decrypts the provided data into a pickle key and base64-encodes it ready for use elsewhere.
*
@ -59,7 +99,7 @@ export function getPickleAdditionalData(userId: string, deviceId: string): Uint8
* @returns A promise that resolves to the encoded pickle key, or undefined if the key cannot be built and encoded.
*/
export async function buildAndEncodePickleKey(
data: { encrypted?: BufferSource; iv?: BufferSource; cryptoKey?: CryptoKey } | undefined,
data: EncryptedPickleKey | undefined,
userId: string,
deviceId: string,
): Promise<string | undefined> {

View file

@ -17,9 +17,10 @@ limitations under the License.
import { Crypto } from "@peculiar/webcrypto";
import { logger } from "matrix-js-sdk/src/logger";
import * as MatrixJs from "matrix-js-sdk/src/matrix";
import { decodeBase64, encodeUnpaddedBase64 } from "matrix-js-sdk/src/matrix";
import { setCrypto } from "matrix-js-sdk/src/crypto/crypto";
import * as MatrixCryptoAes from "matrix-js-sdk/src/crypto/aes";
import { MockedObject } from "jest-mock";
import { mocked, MockedObject } from "jest-mock";
import fetchMock from "fetch-mock-jest";
import StorageEvictedDialog from "../src/components/views/dialogs/StorageEvictedDialog";
@ -27,11 +28,15 @@ import { logout, restoreFromLocalStorage, setLoggedIn } from "../src/Lifecycle";
import { MatrixClientPeg } from "../src/MatrixClientPeg";
import Modal from "../src/Modal";
import * as StorageAccess from "../src/utils/StorageAccess";
import { idbSave } from "../src/utils/StorageAccess";
import { flushPromises, getMockClientWithEventEmitter, mockClientMethodsUser, mockPlatformPeg } from "./test-utils";
import { OidcClientStore } from "../src/stores/oidc/OidcClientStore";
import { makeDelegatedAuthConfig } from "./test-utils/oidc";
import { persistOidcAuthenticatedSettings } from "../src/utils/oidc/persistOidcSettings";
import { Action } from "../src/dispatcher/actions";
import PlatformPeg from "../src/PlatformPeg";
import { persistAccessTokenInStorage, persistRefreshTokenInStorage } from "../src/utils/tokens/tokens";
import { encryptPickleKey } from "../src/utils/tokens/pickling";
const webCrypto = new Crypto();
@ -220,22 +225,18 @@ describe("Lifecycle", () => {
});
describe("when session is found in storage", () => {
describe("guest account", () => {
beforeEach(() => {
initLocalStorageMock(localStorageSession);
initLocalStorageMock({ ...localStorageSession, mx_is_guest: "true" });
initIdbMock(idbStorageSession);
});
describe("guest account", () => {
it("should ignore guest accounts when ignoreGuest is true", async () => {
initLocalStorageMock({ ...localStorageSession, mx_is_guest: "true" });
expect(await restoreFromLocalStorage({ ignoreGuest: true })).toEqual(false);
expect(logger.log).toHaveBeenCalledWith(`Ignoring stored guest account: ${userId}`);
});
it("should restore guest accounts when ignoreGuest is false", async () => {
initLocalStorageMock({ ...localStorageSession, mx_is_guest: "true" });
expect(await restoreFromLocalStorage({ ignoreGuest: false })).toEqual(true);
expect(MatrixClientPeg.replaceUsingCreds).toHaveBeenCalledWith(
@ -250,6 +251,11 @@ describe("Lifecycle", () => {
});
describe("without a pickle key", () => {
beforeEach(() => {
initLocalStorageMock(localStorageSession);
initIdbMock(idbStorageSession);
});
it("should persist credentials", async () => {
expect(await restoreFromLocalStorage()).toEqual(true);
@ -272,7 +278,7 @@ describe("Lifecycle", () => {
expect(localStorage.setItem).toHaveBeenCalledWith("mx_access_token", accessToken);
});
it("should create new matrix client with credentials", async () => {
it("should create and start new matrix client with credentials", async () => {
expect(await restoreFromLocalStorage()).toEqual(true);
expect(MatrixClientPeg.replaceUsingCreds).toHaveBeenCalledWith(
@ -288,6 +294,8 @@ describe("Lifecycle", () => {
},
undefined,
);
expect(MatrixClientPeg.start).toHaveBeenCalledWith({});
});
it("should remove fresh login flag from session storage", async () => {
@ -341,12 +349,20 @@ describe("Lifecycle", () => {
});
});
describe("with a pickle key", () => {
describe("with a normal pickle key", () => {
let pickleKey: string;
beforeEach(async () => {
initLocalStorageMock({});
initLocalStorageMock(localStorageSession);
initIdbMock({});
// setup storage with a session with encrypted token
await setLoggedIn(credentials);
// Create a pickle key, and store it, encrypted, in IDB.
pickleKey = (await PlatformPeg.get()!.createPickleKey(credentials.userId, credentials.deviceId))!;
// Indicate that we should have a pickle key
localStorage.setItem("mx_has_pickle_key", "true");
await persistAccessTokenInStorage(credentials.accessToken, pickleKey);
});
it("should persist credentials", async () => {
@ -383,9 +399,17 @@ describe("Lifecycle", () => {
expect(localStorage.setItem).toHaveBeenCalledWith("mx_access_token", accessToken);
});
it("should create new matrix client with credentials", async () => {
it("should create and start new matrix client with credentials", async () => {
// Check that the rust crypto key is as expected. We have to do this during the call, as
// the buffer is cleared afterwards.
mocked(MatrixClientPeg.start).mockImplementation(async (opts) => {
expect(opts?.rustCryptoStoreKey).toEqual(decodeBase64(pickleKey));
});
// Perform the restore
expect(await restoreFromLocalStorage()).toEqual(true);
// Ensure that the expected calls were made
expect(MatrixClientPeg.replaceUsingCreds).toHaveBeenCalledWith(
{
userId,
@ -394,23 +418,19 @@ describe("Lifecycle", () => {
homeserverUrl,
identityServerUrl,
deviceId,
freshLogin: true,
freshLogin: false,
guest: false,
pickleKey: expect.any(String),
pickleKey,
},
undefined,
);
expect(MatrixClientPeg.start).toHaveBeenCalledWith({ rustCryptoStoreKey: expect.any(Buffer) });
});
describe("with a refresh token", () => {
beforeEach(async () => {
initLocalStorageMock({});
initIdbMock({});
// setup storage with a session with encrypted token
await setLoggedIn({
...credentials,
refreshToken,
});
await persistRefreshTokenInStorage(refreshToken, pickleKey);
});
it("should persist credentials", async () => {
@ -439,7 +459,7 @@ describe("Lifecycle", () => {
deviceId,
freshLogin: false,
guest: false,
pickleKey: expect.any(String),
pickleKey: pickleKey,
},
undefined,
);
@ -447,7 +467,60 @@ describe("Lifecycle", () => {
});
});
describe("with a non-standard pickle key", () => {
// Most pickle keys are 43 bytes of base64. Test what happens when it is something else.
let pickleKey: string;
beforeEach(async () => {
initLocalStorageMock(localStorageSession);
initIdbMock({});
// Generate the pickle key. I don't *think* it's possible for there to be a pickle key
// which is not some amount of base64.
const rawPickleKey = new Uint8Array(10);
crypto.getRandomValues(rawPickleKey);
pickleKey = encodeUnpaddedBase64(rawPickleKey);
// Store it, encrypted, in the db
await idbSave(
"pickleKey",
[userId, deviceId],
(await encryptPickleKey(rawPickleKey, userId, deviceId))!,
);
// Indicate that we should have a pickle key
localStorage.setItem("mx_has_pickle_key", "true");
await persistAccessTokenInStorage(credentials.accessToken, pickleKey);
});
it("should create and start new matrix client with credentials", async () => {
// Perform the restore
expect(await restoreFromLocalStorage()).toEqual(true);
// Ensure that the expected calls were made
expect(MatrixClientPeg.replaceUsingCreds).toHaveBeenCalledWith(
{
userId,
// decrypted accessToken
accessToken,
homeserverUrl,
identityServerUrl,
deviceId,
freshLogin: false,
guest: false,
pickleKey,
},
undefined,
);
expect(MatrixClientPeg.start).toHaveBeenCalledWith({ rustCryptoStorePassword: pickleKey });
});
});
it("should proceed if server is not accessible", async () => {
initLocalStorageMock(localStorageSession);
initIdbMock(idbStorageSession);
mockClient.isVersionSupported.mockRejectedValue(new Error("Oh, noes, the server is down!"));
expect(await restoreFromLocalStorage()).toEqual(true);

View file

@ -217,7 +217,7 @@ describe("MatrixClientPeg", () => {
testPeg.safeGet().store.on = emitter.on.bind(emitter);
const platform: any = { reload: jest.fn() };
PlatformPeg.set(platform);
await testPeg.assign();
await testPeg.assign({});
emitter.emit("closed" as any);
expect(platform.reload).toHaveBeenCalled();
});
@ -229,7 +229,7 @@ describe("MatrixClientPeg", () => {
PlatformPeg.set(platform);
testPeg.safeGet().store.on = emitter.on.bind(emitter);
const spy = jest.spyOn(Modal, "createDialog");
await testPeg.assign();
await testPeg.assign({});
emitter.emit("closed" as any);
expect(spy).toHaveBeenCalled();
});
@ -243,9 +243,10 @@ describe("MatrixClientPeg", () => {
const mockInitCrypto = jest.spyOn(testPeg.safeGet(), "initCrypto").mockResolvedValue(undefined);
const mockInitRustCrypto = jest.spyOn(testPeg.safeGet(), "initRustCrypto").mockResolvedValue(undefined);
await testPeg.start();
const cryptoStoreKey = new Uint8Array([1, 2, 3, 4]);
await testPeg.start({ rustCryptoStoreKey: cryptoStoreKey });
expect(mockInitCrypto).not.toHaveBeenCalled();
expect(mockInitRustCrypto).toHaveBeenCalledTimes(1);
expect(mockInitRustCrypto).toHaveBeenCalledWith({ storageKey: cryptoStoreKey });
// we should have stashed the setting in the settings store
expect(mockSetValue).toHaveBeenCalledWith("feature_rust_crypto", null, SettingLevel.DEVICE, true);
@ -271,7 +272,7 @@ describe("MatrixClientPeg", () => {
await testPeg.start();
expect(mockInitCrypto).toHaveBeenCalled();
expect(mockInitRustCrypto).not.toHaveBeenCalledTimes(1);
expect(mockInitRustCrypto).not.toHaveBeenCalled();
// we should have stashed the setting in the settings store
expect(mockSetValue).toHaveBeenCalledWith("feature_rust_crypto", null, SettingLevel.DEVICE, false);