element-web/src/SecurityManager.ts

307 lines
12 KiB
TypeScript

/*
Copyright 2024 New Vector Ltd.
Copyright 2019, 2020 The Matrix.org Foundation C.I.C.
SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only
Please see LICENSE files in the repository root for full details.
*/
import { ICryptoCallbacks, SecretStorage } from "matrix-js-sdk/src/matrix";
import { deriveRecoveryKeyFromPassphrase, decodeRecoveryKey } from "matrix-js-sdk/src/crypto-api";
import { logger } from "matrix-js-sdk/src/logger";
import type CreateSecretStorageDialog from "./async-components/views/dialogs/security/CreateSecretStorageDialog";
import Modal from "./Modal";
import { MatrixClientPeg } from "./MatrixClientPeg";
import { _t } from "./languageHandler";
import { isSecureBackupRequired } from "./utils/WellKnownUtils";
import AccessSecretStorageDialog, { KeyParams } from "./components/views/dialogs/security/AccessSecretStorageDialog";
import SettingsStore from "./settings/SettingsStore";
import { ModuleRunner } from "./modules/ModuleRunner";
import QuestionDialog from "./components/views/dialogs/QuestionDialog";
import InteractiveAuthDialog from "./components/views/dialogs/InteractiveAuthDialog";
// This stores the secret storage private keys in memory for the JS SDK. This is
// only meant to act as a cache to avoid prompting the user multiple times
// during the same single operation. Use `accessSecretStorage` below to scope a
// single secret storage operation, as it will clear the cached keys once the
// operation ends.
let secretStorageKeys: Record<string, Uint8Array> = {};
let secretStorageKeyInfo: Record<string, SecretStorage.SecretStorageKeyDescription> = {};
let secretStorageBeingAccessed = false;
/**
* This can be used by other components to check if secret storage access is in
* progress, so that we can e.g. avoid intermittently showing toasts during
* secret storage setup.
*
* @returns {bool}
*/
export function isSecretStorageBeingAccessed(): boolean {
return secretStorageBeingAccessed;
}
export class AccessCancelledError extends Error {
public constructor() {
super("Secret storage access canceled");
}
}
async function confirmToDismiss(): Promise<boolean> {
const [sure] = await Modal.createDialog(QuestionDialog, {
title: _t("encryption|cancel_entering_passphrase_title"),
description: _t("encryption|cancel_entering_passphrase_description"),
danger: false,
button: _t("action|go_back"),
cancelButton: _t("action|cancel"),
}).finished;
return !sure;
}
function makeInputToKey(
keyInfo: SecretStorage.SecretStorageKeyDescription,
): (keyParams: KeyParams) => Promise<Uint8Array> {
return async ({ passphrase, recoveryKey }): Promise<Uint8Array> => {
if (passphrase) {
return deriveRecoveryKeyFromPassphrase(passphrase, keyInfo.passphrase.salt, keyInfo.passphrase.iterations);
} else if (recoveryKey) {
return decodeRecoveryKey(recoveryKey);
}
throw new Error("Invalid input, passphrase or recoveryKey need to be provided");
};
}
async function getSecretStorageKey({
keys: keyInfos,
}: {
keys: Record<string, SecretStorage.SecretStorageKeyDescription>;
}): Promise<[string, Uint8Array]> {
const cli = MatrixClientPeg.safeGet();
let keyId = await cli.getDefaultSecretStorageKeyId();
let keyInfo!: SecretStorage.SecretStorageKeyDescription;
if (keyId) {
// use the default SSSS key if set
keyInfo = keyInfos[keyId];
if (!keyInfo) {
// if the default key is not available, pretend the default key
// isn't set
keyId = null;
}
}
if (!keyId) {
// if no default SSSS key is set, fall back to a heuristic of using the
// only available key, if only one key is set
const keyInfoEntries = Object.entries(keyInfos);
if (keyInfoEntries.length > 1) {
throw new Error("Multiple storage key requests not implemented");
}
[keyId, keyInfo] = keyInfoEntries[0];
}
logger.debug(`getSecretStorageKey: request for 4S keys [${Object.keys(keyInfos)}]: looking for key ${keyId}`);
// Check the in-memory cache
if (secretStorageBeingAccessed && secretStorageKeys[keyId]) {
logger.debug(`getSecretStorageKey: returning key ${keyId} from cache`);
return [keyId, secretStorageKeys[keyId]];
}
const keyFromCustomisations = ModuleRunner.instance.extensions.cryptoSetup.getSecretStorageKey();
if (keyFromCustomisations) {
logger.log("getSecretStorageKey: Using secret storage key from CryptoSetupExtension");
cacheSecretStorageKey(keyId, keyInfo, keyFromCustomisations);
return [keyId, keyFromCustomisations];
}
logger.debug("getSecretStorageKey: prompting user for key");
const inputToKey = makeInputToKey(keyInfo);
const { finished } = Modal.createDialog(
AccessSecretStorageDialog,
/* props= */
{
keyInfo,
checkPrivateKey: async (input: KeyParams): Promise<boolean> => {
const key = await inputToKey(input);
return MatrixClientPeg.safeGet().checkSecretStorageKey(key, keyInfo);
},
},
/* className= */ undefined,
/* isPriorityModal= */ false,
/* isStaticModal= */ false,
/* options= */ {
onBeforeClose: async (reason): Promise<boolean> => {
if (reason === "backgroundClick") {
return confirmToDismiss();
}
return true;
},
},
);
const [keyParams] = await finished;
if (!keyParams) {
throw new AccessCancelledError();
}
logger.debug("getSecretStorageKey: got key from user");
const key = await inputToKey(keyParams);
// Save to cache to avoid future prompts in the current session
cacheSecretStorageKey(keyId, keyInfo, key);
return [keyId, key];
}
function cacheSecretStorageKey(
keyId: string,
keyInfo: SecretStorage.SecretStorageKeyDescription,
key: Uint8Array,
): void {
if (secretStorageBeingAccessed) {
secretStorageKeys[keyId] = key;
secretStorageKeyInfo[keyId] = keyInfo;
}
}
export const crossSigningCallbacks: ICryptoCallbacks = {
getSecretStorageKey,
cacheSecretStorageKey,
};
/**
* Carry out an operation that may require multiple accesses to secret storage, caching the key.
*
* Use this helper to wrap an operation that may require multiple accesses to secret storage; the user will be prompted
* to enter the 4S key or passphrase on the first access, and the key will be cached for the rest of the operation.
*
* @param func - The operation to be wrapped.
*/
export async function withSecretStorageKeyCache<T>(func: () => Promise<T>): Promise<T> {
logger.debug("SecurityManager: enabling 4S key cache");
secretStorageBeingAccessed = true;
try {
return await func();
} finally {
// Clear secret storage key cache now that work is complete
logger.debug("SecurityManager: disabling 4S key cache");
secretStorageBeingAccessed = false;
secretStorageKeys = {};
secretStorageKeyInfo = {};
}
}
/**
* This helper should be used whenever you need to access secret storage. It
* ensures that secret storage (and also cross-signing since they each depend on
* each other in a cycle of sorts) have been bootstrapped before running the
* provided function.
*
* Bootstrapping secret storage may take one of these paths:
* 1. Create secret storage from a passphrase and store cross-signing keys
* in secret storage.
* 2. Access existing secret storage by requesting passphrase and accessing
* cross-signing keys as needed.
* 3. All keys are loaded and there's nothing to do.
*
* Additionally, the secret storage keys are cached during the scope of this function
* to ensure the user is prompted only once for their secret storage
* passphrase. The cache is then cleared once the provided function completes.
*
* @param {Function} [func] An operation to perform once secret storage has been
* bootstrapped. Optional.
* @param {bool} [forceReset] Reset secret storage even if it's already set up
*/
export async function accessSecretStorage(func = async (): Promise<void> => {}, forceReset = false): Promise<void> {
await withSecretStorageKeyCache(() => doAccessSecretStorage(func, forceReset));
}
/** Helper for {@link #accessSecretStorage} */
async function doAccessSecretStorage(func: () => Promise<void>, forceReset: boolean): Promise<void> {
try {
const cli = MatrixClientPeg.safeGet();
const crypto = cli.getCrypto();
if (!crypto) {
throw new Error("End-to-end encryption is disabled - unable to access secret storage.");
}
let createNew = false;
if (forceReset) {
logger.debug("accessSecretStorage: resetting 4S");
createNew = true;
} else if (!(await cli.secretStorage.hasKey())) {
logger.debug("accessSecretStorage: no 4S key configured, creating a new one");
createNew = true;
}
if (createNew) {
// This dialog calls bootstrap itself after guiding the user through
// passphrase creation.
const { finished } = Modal.createDialogAsync(
import("./async-components/views/dialogs/security/CreateSecretStorageDialog") as unknown as Promise<
typeof CreateSecretStorageDialog
>,
{
forceReset,
},
undefined,
/* priority = */ false,
/* static = */ true,
/* options = */ {
onBeforeClose: async (reason): Promise<boolean> => {
// If Secure Backup is required, you cannot leave the modal.
if (reason === "backgroundClick") {
return !isSecureBackupRequired(cli);
}
return true;
},
},
);
const [confirmed] = await finished;
if (!confirmed) {
throw new Error("Secret storage creation canceled");
}
} else {
logger.debug("accessSecretStorage: bootstrapCrossSigning");
await crypto.bootstrapCrossSigning({
authUploadDeviceSigningKeys: async (makeRequest): Promise<void> => {
logger.debug("accessSecretStorage: performing UIA to upload cross-signing keys");
const { finished } = Modal.createDialog(InteractiveAuthDialog, {
title: _t("encryption|bootstrap_title"),
matrixClient: cli,
makeRequest,
});
const [confirmed] = await finished;
if (!confirmed) {
throw new Error("Cross-signing key upload auth canceled");
}
logger.debug("accessSecretStorage: Cross-signing key upload successful");
},
});
logger.debug("accessSecretStorage: bootstrapSecretStorage");
await crypto.bootstrapSecretStorage({});
const keyId = Object.keys(secretStorageKeys)[0];
if (keyId && SettingsStore.getValue("feature_dehydration")) {
let dehydrationKeyInfo = {};
if (secretStorageKeyInfo[keyId] && secretStorageKeyInfo[keyId].passphrase) {
dehydrationKeyInfo = { passphrase: secretStorageKeyInfo[keyId].passphrase };
}
logger.log("accessSecretStorage: Setting dehydration key");
await cli.setDehydrationKey(secretStorageKeys[keyId], dehydrationKeyInfo, "Backup device");
} else if (!keyId) {
logger.warn("accessSecretStorage: Not setting dehydration key: no SSSS key found");
} else {
logger.log("accessSecretStorage: Not setting dehydration key: feature disabled");
}
}
logger.debug("accessSecretStorage: 4S now ready");
// `return await` needed here to ensure `finally` block runs after the
// inner operation completes.
await func();
logger.debug("accessSecretStorage: operation complete");
} catch (e) {
ModuleRunner.instance.extensions.cryptoSetup.catchAccessSecretStorageError(e as Error);
logger.error("accessSecretStorage: error during operation", e);
// Re-throw so that higher level logic can abort as needed
throw e;
}
}