forked from mystiq/hydrogen-web
move curve25519 code to separate file
This commit is contained in:
Bruno Windels
parent
86caa5f9b1
commit
cfb94206f9
2 changed files with 113 additions and 91 deletions
89
src/matrix/e2ee/megolm/keybackup/Curve25519.ts
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89
src/matrix/e2ee/megolm/keybackup/Curve25519.ts
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@ -0,0 +1,89 @@
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/*
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Copyright 2022 The Matrix.org Foundation C.I.C.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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import {MEGOLM_ALGORITHM} from "../../common";
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import type {RoomKey} from "../decryption/RoomKey";
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import type {BaseBackupInfo, SignatureMap, SessionKeyInfo} from "./KeyBackup";
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import type * as OlmNamespace from "@matrix-org/olm";
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type Olm = typeof OlmNamespace;
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export const Algorithm = "m.megolm_backup.v1.curve25519-aes-sha2";
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export type BackupInfo = BaseBackupInfo & {
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algorithm: typeof Algorithm,
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auth_data: AuthData,
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}
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export type AuthData = {
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public_key: string,
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signatures: SignatureMap
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}
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export type SessionData = {
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ciphertext: string,
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mac: string,
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ephemeral: string,
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}
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export class BackupEncryption {
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constructor(
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private readonly encryption: Olm.PkEncryption,
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private readonly decryption: Olm.PkDecryption
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) {}
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static fromAuthData(authData: AuthData, privateKey: Uint8Array, olm: Olm): BackupEncryption {
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const expectedPubKey = authData.public_key;
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const decryption = new olm.PkDecryption();
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const encryption = new olm.PkEncryption();
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try {
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const pubKey = decryption.init_with_private_key(privateKey);
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if (pubKey !== expectedPubKey) {
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throw new Error(`Bad backup key, public key does not match. Calculated ${pubKey} but expected ${expectedPubKey}`);
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}
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encryption.set_recipient_key(pubKey);
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} catch(err) {
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decryption.free();
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throw err;
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}
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return new BackupEncryption(encryption, decryption);
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}
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decryptRoomKey(sessionData: SessionData): SessionKeyInfo {
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const sessionInfo = this.decryption.decrypt(
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sessionData.ephemeral,
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sessionData.mac,
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sessionData.ciphertext,
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);
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return JSON.parse(sessionInfo) as SessionKeyInfo;
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}
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encryptRoomKey(key: RoomKey, sessionKey: string): SessionData {
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const sessionInfo: SessionKeyInfo = {
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algorithm: MEGOLM_ALGORITHM,
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sender_key: key.senderKey,
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sender_claimed_keys: {ed25519: key.claimedEd25519Key},
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forwarding_curve25519_key_chain: [],
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session_key: sessionKey
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};
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return this.encryption.encrypt(JSON.stringify(sessionInfo)) as SessionData;
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}
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dispose() {
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this.decryption.free();
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this.encryption.free();
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}
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}
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@ -15,9 +15,9 @@ limitations under the License.
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*/
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import {StoreNames} from "../../../storage/common";
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import {LRUCache} from "../../../../utils/LRUCache";
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import {keyFromStorage, keyFromBackup} from "../decryption/RoomKey";
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import {MEGOLM_ALGORITHM} from "../../common";
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import * as Curve25519 from "./Curve25519";
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import type {HomeServerApi} from "../../../net/HomeServerApi";
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import type {IncomingRoomKey, RoomKey} from "../decryption/RoomKey";
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@ -31,48 +31,28 @@ import type {Transaction} from "../../../storage/idb/Transaction";
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import type * as OlmNamespace from "@matrix-org/olm";
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type Olm = typeof OlmNamespace;
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type SignatureMap = {
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export type SignatureMap = {
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[userId: string]: {[deviceIdAndAlgorithm: string]: string}
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}
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interface BaseBackupInfo {
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export type BaseBackupInfo = {
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version: string,
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etag: string,
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count: number,
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}
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const Curve25519Algorithm = "m.megolm_backup.v1.curve25519-aes-sha2";
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interface Curve25519BackupInfo extends BaseBackupInfo {
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algorithm: typeof Curve25519Algorithm,
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auth_data: Curve25519AuthData,
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}
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interface OtherBackupInfo extends BaseBackupInfo {
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type OtherBackupInfo = BaseBackupInfo & {
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algorithm: "other"
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};
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type BackupInfo = Curve25519BackupInfo | OtherBackupInfo;
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interface Curve25519AuthData {
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public_key: string,
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signatures: SignatureMap
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}
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type AuthData = Curve25519AuthData;
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type BackupInfo = Curve25519.BackupInfo | OtherBackupInfo;
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type AuthData = Curve25519.AuthData;
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type SessionInfo = {
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first_message_index: number,
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forwarded_count: number,
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is_verified: boolean,
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session_data: Curve29915SessionData | any
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}
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type Curve29915SessionData = {
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ciphertext: string,
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mac: string,
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ephemeral: string,
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session_data: Curve25519.SessionData | any
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}
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type MegOlmSessionKeyInfo = {
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@ -83,12 +63,20 @@ type MegOlmSessionKeyInfo = {
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session_key: string
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}
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type SessionKeyInfo = MegOlmSessionKeyInfo | {algorithm: string};
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export type SessionKeyInfo = MegOlmSessionKeyInfo | {algorithm: string};
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type KeyBackupPayload = {
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rooms: {
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[roomId: string]: {
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sessions: {[sessionId: string]: SessionInfo}
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}
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}
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}
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export class KeyBackup {
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constructor(
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private readonly backupInfo: BackupInfo,
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private readonly algorithm: Curve25519,
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private readonly crypto: Curve25519.BackupEncryption,
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private readonly hsApi: HomeServerApi,
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private readonly keyLoader: KeyLoader,
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private readonly storage: Storage,
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@ -100,7 +88,7 @@ export class KeyBackup {
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if (!sessionResponse.session_data) {
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return;
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}
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const sessionKeyInfo = this.algorithm.decryptRoomKey(sessionResponse.session_data);
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const sessionKeyInfo = this.crypto.decryptRoomKey(sessionResponse.session_data as Curve25519.SessionData);
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if (sessionKeyInfo?.algorithm === MEGOLM_ALGORITHM) {
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return keyFromBackup(roomId, sessionId, sessionKeyInfo);
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} else if (sessionKeyInfo?.algorithm) {
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@ -131,13 +119,7 @@ export class KeyBackup {
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return;
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}
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const roomKeys = await Promise.all(keysNeedingBackup.map(k => keyFromStorage(k.roomId, k.senderKey, k.sessionId, txn)));
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const payload: {
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rooms: {
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[roomId: string]: {
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sessions: {[sessionId: string]: SessionInfo}
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}
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}
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} = { rooms: {} };
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const payload: KeyBackupPayload = { rooms: {} };
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const payloadRooms = payload.rooms;
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for (const key of roomKeys) {
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if (key) {
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@ -174,7 +156,7 @@ export class KeyBackup {
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first_message_index: firstMessageIndex,
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forwarded_count: 0,
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is_verified: false,
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session_data: this.algorithm.encryptRoomKey(roomKey, sessionKey)
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session_data: this.crypto.encryptRoomKey(roomKey, sessionKey)
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};
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});
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}
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@ -184,7 +166,7 @@ export class KeyBackup {
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}
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dispose() {
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this.algorithm.dispose();
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this.crypto.dispose();
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}
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static async fromSecretStorage(platform: Platform, olm: Olm, secretStorage: SecretStorage, hsApi: HomeServerApi, keyLoader: KeyLoader, storage: Storage, txn: Transaction): Promise<KeyBackup | undefined> {
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@ -192,61 +174,12 @@ export class KeyBackup {
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if (base64PrivateKey) {
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const privateKey = new Uint8Array(platform.encoding.base64.decode(base64PrivateKey));
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const backupInfo = await hsApi.roomKeysVersion().response() as BackupInfo;
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if (backupInfo.algorithm === Curve25519Algorithm) {
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const algorithm = Curve25519.fromAuthData(backupInfo.auth_data, privateKey, olm);
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return new KeyBackup(backupInfo, algorithm, hsApi, keyLoader, storage, platform);
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if (backupInfo.algorithm === Curve25519.Algorithm) {
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const crypto = Curve25519.BackupEncryption.fromAuthData(backupInfo.auth_data, privateKey, olm);
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return new KeyBackup(backupInfo, crypto, hsApi, keyLoader, storage, platform);
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} else {
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throw new Error(`Unknown backup algorithm: ${backupInfo.algorithm}`);
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}
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}
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}
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}
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class Curve25519 {
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constructor(
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private readonly encryption: Olm.PkEncryption,
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private readonly decryption: Olm.PkDecryption
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) {}
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static fromAuthData(authData: Curve25519AuthData, privateKey: Uint8Array, olm: Olm): Curve25519 {
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const expectedPubKey = authData.public_key;
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const decryption = new olm.PkDecryption();
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const encryption = new olm.PkEncryption();
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try {
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const pubKey = decryption.init_with_private_key(privateKey);
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if (pubKey !== expectedPubKey) {
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throw new Error(`Bad backup key, public key does not match. Calculated ${pubKey} but expected ${expectedPubKey}`);
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}
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encryption.set_recipient_key(pubKey);
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} catch(err) {
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decryption.free();
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throw err;
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}
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return new Curve25519(encryption, decryption);
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}
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decryptRoomKey(sessionData: Curve29915SessionData): SessionKeyInfo {
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const sessionInfo = this.decryption.decrypt(
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sessionData.ephemeral,
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sessionData.mac,
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sessionData.ciphertext,
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);
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return JSON.parse(sessionInfo) as SessionKeyInfo;
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}
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encryptRoomKey(key: RoomKey, sessionKey: string): Curve29915SessionData {
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const sessionInfo: SessionKeyInfo = {
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algorithm: MEGOLM_ALGORITHM,
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sender_key: key.senderKey,
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sender_claimed_keys: {ed25519: key.claimedEd25519Key},
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forwarding_curve25519_key_chain: [],
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session_key: sessionKey
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};
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return this.encryption.encrypt(JSON.stringify(sessionInfo)) as Curve29915SessionData;
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}
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dispose() {
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this.decryption.free();
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this.encryption.free();
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}
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}
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