convert SessionBackup to typescript and pass in keyloader

src/matrix/Session.js

@@ -70,6 +70,7 @@ export class Session {
         this._e2eeAccount = null;
         this._deviceTracker = null;
         this._olmEncryption = null;
+        this._keyLoader = null;
         this._megolmEncryption = null;
         this._megolmDecryption = null;
         this._getSyncToken = () => this.syncToken;
@@ -141,8 +142,8 @@ export class Session {
             now: this._platform.clock.now,
             ownDeviceId: this._sessionInfo.deviceId,
         });
-        const keyLoader = new MegOlmKeyLoader(this._olm, PICKLE_KEY, 20);
-        this._megolmDecryption = new MegOlmDecryption(keyLoader, this._olmWorker);
+        this._keyLoader = new MegOlmKeyLoader(this._olm, PICKLE_KEY, 20);
+        this._megolmDecryption = new MegOlmDecryption(this._keyLoader, this._olmWorker);
         this._deviceMessageHandler.enableEncryption({olmDecryption, megolmDecryption: this._megolmDecryption});
     }
 
@@ -246,12 +247,14 @@ export class Session {
 
     async _createSessionBackup(ssssKey, txn) {
         const secretStorage = new SecretStorage({key: ssssKey, platform: this._platform});
-        this._sessionBackup = await SessionBackup.fromSecretStorage({
-            platform: this._platform,
-            olm: this._olm, secretStorage,
-            hsApi: this._hsApi,
+        this._sessionBackup = await SessionBackup.fromSecretStorage(
+            this._platform,
+            this._olm,
+            secretStorage,
+            this._hsApi,
+            this._keyLoader,
             txn
-        });
+        );
         if (this._sessionBackup) {
             for (const room of this._rooms.values()) {
                 if (room.isEncrypted) {

src/matrix/e2ee/megolm/SessionBackup.js

@@ -1,62 +0,0 @@
-/*
-Copyright 2020 The Matrix.org Foundation C.I.C.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-export class SessionBackup {
-    constructor({backupInfo, decryption, hsApi}) {
-        this._backupInfo = backupInfo;
-        this._decryption = decryption;
-        this._hsApi = hsApi;
-    }
-
-    async getSession(roomId, sessionId, log) {
-        const sessionResponse = await this._hsApi.roomKeyForRoomAndSession(this._backupInfo.version, roomId, sessionId, {log}).response();
-        const sessionInfo = this._decryption.decrypt(
-            sessionResponse.session_data.ephemeral,
-            sessionResponse.session_data.mac,
-            sessionResponse.session_data.ciphertext,
-        );
-        return JSON.parse(sessionInfo);
-    }
-
-    get version() {
-        return this._backupInfo.version;
-    }
-
-    dispose() {
-        this._decryption.free();
-    }
-
-    static async fromSecretStorage({platform, olm, secretStorage, hsApi, txn}) {
-        const base64PrivateKey = await secretStorage.readSecret("m.megolm_backup.v1", txn);
-        if (base64PrivateKey) {
-            const privateKey = new Uint8Array(platform.encoding.base64.decode(base64PrivateKey));
-            const backupInfo = await hsApi.roomKeysVersion().response();
-            const expectedPubKey = backupInfo.auth_data.public_key;
-            const decryption = new olm.PkDecryption();
-            try {
-                const pubKey = decryption.init_with_private_key(privateKey);
-                if (pubKey !== expectedPubKey) {
-                    throw new Error(`Bad backup key, public key does not match. Calculated ${pubKey} but expected ${expectedPubKey}`);
-                }
-            } catch(err) {
-                decryption.free();
-                throw err;
-            }
-            return new SessionBackup({backupInfo, decryption, hsApi});
-        }
-    }
-}
-

src/matrix/e2ee/megolm/SessionBackup.ts

@@ -0,0 +1,107 @@
+/*
+Copyright 2020 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import type {HomeServerApi} from "../../net/HomeServerApi";
+import type {RoomKey} from "./decryption/RoomKey";
+import type {KeyLoader} from "./decryption/KeyLoader";
+import type {SecretStorage} from "../../ssss/SecretStorage";
+import type {ILogItem} from "../../../logging/types";
+import type {Platform} from "../../../platform/web/Platform";
+import type {Transaction} from "../../storage/idb/Transaction";
+import type * as OlmNamespace from "@matrix-org/olm";
+type Olm = typeof OlmNamespace;
+
+type SignatureMap = {
+    [userId: string]: {[deviceIdAndAlgorithm: string]: string}
+}
+
+interface BaseBackupInfo {
+    version: string,
+    etag: string,
+    count: number,
+}
+
+const Curve25519Algorithm = "m.megolm_backup.v1.curve25519-aes-sha2";
+
+interface Curve25519BackupInfo extends BaseBackupInfo {
+    algorithm: typeof Curve25519Algorithm,
+    auth_data: Curve25519AuthData,
+}
+
+interface OtherBackupInfo extends BaseBackupInfo {
+    algorithm: "other"
+};
+
+type BackupInfo = Curve25519BackupInfo | OtherBackupInfo;
+
+interface Curve25519AuthData {
+    public_key: string,
+    signatures: SignatureMap
+}
+
+type AuthData = Curve25519AuthData;
+
+export class SessionBackup {
+    constructor(
+        private readonly backupInfo: BackupInfo,
+        private readonly decryption: Olm.PkDecryption,
+        private readonly hsApi: HomeServerApi,
+        private readonly keyLoader: KeyLoader
+    ) {}
+
+    async getSession(roomId: string, sessionId: string, log: ILogItem) {
+        const sessionResponse = await this.hsApi.roomKeyForRoomAndSession(this.backupInfo.version, roomId, sessionId, {log}).response();
+        const sessionInfo = this.decryption.decrypt(
+            sessionResponse.session_data.ephemeral,
+            sessionResponse.session_data.mac,
+            sessionResponse.session_data.ciphertext,
+        );
+        return JSON.parse(sessionInfo);
+    }
+
+    get version() {
+        return this.backupInfo.version;
+    }
+
+    dispose() {
+        this.decryption.free();
+    }
+
+    static async fromSecretStorage(platform: Platform, olm: Olm, secretStorage: SecretStorage, hsApi: HomeServerApi, keyLoader: KeyLoader, txn: Transaction) {
+        const base64PrivateKey = await secretStorage.readSecret("m.megolm_backup.v1", txn);
+        if (base64PrivateKey) {
+            const privateKey = new Uint8Array(platform.encoding.base64.decode(base64PrivateKey));
+            const backupInfo = await hsApi.roomKeysVersion().response() as BackupInfo;
+            if (backupInfo.algorithm === Curve25519Algorithm) {
+                const expectedPubKey = backupInfo.auth_data.public_key;
+                const decryption = new olm.PkDecryption();
+                try {
+                    const pubKey = decryption.init_with_private_key(privateKey);
+                    if (pubKey !== expectedPubKey) {
+                        throw new Error(`Bad backup key, public key does not match. Calculated ${pubKey} but expected ${expectedPubKey}`);
+                    }
+                } catch(err) {
+                    decryption.free();
+                    throw err;
+                }
+                return new SessionBackup(backupInfo, decryption, hsApi, keyLoader);
+            } else {
+                throw new Error(`Unknown backup algorithm: ${backupInfo.algorithm}`);
+            }
+        }
+    }
+}
+