127 lines
3.6 KiB
TypeScript
127 lines
3.6 KiB
TypeScript
// Copyright 2024 Signal Messenger, LLC
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// SPDX-License-Identifier: AGPL-3.0-only
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import memoizee from 'memoizee';
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import type { PrivateKey } from '@signalapp/libsignal-client';
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import {
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AccountEntropyPool,
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BackupKey,
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} from '@signalapp/libsignal-client/dist/AccountKeys';
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import { MessageBackupKey } from '@signalapp/libsignal-client/dist/MessageBackup';
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import { strictAssert } from '../../util/assert';
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import type { AciString } from '../../types/ServiceId';
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import { toAciObject } from '../../util/ServiceId';
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const getMemoizedBackupKey = memoizee((accountEntropyPool: string) => {
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return AccountEntropyPool.deriveBackupKey(accountEntropyPool);
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});
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export function getBackupKey(): BackupKey {
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const accountEntropyPool = window.storage.get('accountEntropyPool');
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strictAssert(accountEntropyPool, 'Account Entropy Pool not available');
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return getMemoizedBackupKey(accountEntropyPool);
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}
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export function getBackupMediaRootKey(): BackupKey {
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const rootKey = window.storage.get('backupMediaRootKey');
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strictAssert(rootKey, 'Media root key not available');
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return new BackupKey(Buffer.from(rootKey));
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}
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const getMemoizedBackupSignatureKey = memoizee(
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(backupKey: BackupKey, aci: AciString) => {
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return backupKey.deriveEcKey(toAciObject(aci));
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}
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);
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export function getBackupSignatureKey(): PrivateKey {
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const backupKey = getBackupKey();
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const aci = window.storage.user.getCheckedAci();
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return getMemoizedBackupSignatureKey(backupKey, aci);
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}
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const getMemoizedBackupMediaSignatureKey = memoizee(
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(rootKey: BackupKey, aci: AciString) => {
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return rootKey.deriveEcKey(toAciObject(aci));
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}
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);
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export function getBackupMediaSignatureKey(): PrivateKey {
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const rootKey = getBackupMediaRootKey();
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const aci = window.storage.user.getCheckedAci();
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return getMemoizedBackupMediaSignatureKey(rootKey, aci);
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}
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const getMemoizedKeyMaterial = memoizee(
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(backupKey: BackupKey, aci: AciString) => {
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const messageKey = new MessageBackupKey({
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backupKey,
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backupId: backupKey.deriveBackupId(toAciObject(aci)),
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});
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return { macKey: messageKey.hmacKey, aesKey: messageKey.aesKey };
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}
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);
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export type BackupKeyMaterialType = Readonly<{
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macKey: Uint8Array;
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aesKey: Uint8Array;
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}>;
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export function getKeyMaterial(
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backupKey = getBackupKey()
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): BackupKeyMaterialType {
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const aci = window.storage.user.getCheckedAci();
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return getMemoizedKeyMaterial(backupKey, aci);
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}
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export type BackupMediaKeyMaterialType = Readonly<{
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macKey: Uint8Array;
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aesKey: Uint8Array;
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}>;
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const BACKUP_MEDIA_AES_KEY_LEN = 32;
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const BACKUP_MEDIA_MAC_KEY_LEN = 32;
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export function deriveBackupMediaKeyMaterial(
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mediaRootKey: BackupKey,
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mediaId: Uint8Array
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): BackupMediaKeyMaterialType {
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if (!mediaId.length) {
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throw new Error('deriveBackupMediaKeyMaterial: mediaId missing');
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}
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const material = mediaRootKey.deriveMediaEncryptionKey(Buffer.from(mediaId));
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return {
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macKey: material.subarray(0, BACKUP_MEDIA_MAC_KEY_LEN),
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aesKey: material.subarray(
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BACKUP_MEDIA_MAC_KEY_LEN,
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BACKUP_MEDIA_MAC_KEY_LEN + BACKUP_MEDIA_AES_KEY_LEN
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),
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};
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}
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export function deriveBackupThumbnailTransitKeyMaterial(
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mediaRootKey: BackupKey,
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mediaId: Uint8Array
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): BackupMediaKeyMaterialType {
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if (!mediaId.length) {
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throw new Error('deriveBackupThumbnailTransitKeyMaterial: mediaId missing');
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}
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const material = mediaRootKey.deriveThumbnailTransitEncryptionKey(
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Buffer.from(mediaId)
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);
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return {
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macKey: material.subarray(0, BACKUP_MEDIA_MAC_KEY_LEN),
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aesKey: material.subarray(
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BACKUP_MEDIA_MAC_KEY_LEN,
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BACKUP_MEDIA_MAC_KEY_LEN + BACKUP_MEDIA_AES_KEY_LEN
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),
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};
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}
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