Enable generic secrets on local machine via ipc

Signed-off-by: Nils Hanff <[email protected]>

src/ipc.ts

@@ -23,6 +23,7 @@ import { randomArray } from "./utils";
 import { Settings } from "./settings";
 import { keytar } from "./keytar";
 import { getDisplayMediaCallback, setDisplayMediaCallback } from "./displayMediaCallback";
+import { getSecretStore } from "./secrets";
 
 ipcMain.on("setBadgeCount", function (_ev: IpcMainEvent, count: number): void {
     if (process.platform !== "win32") {
@@ -147,6 +148,26 @@ ipcMain.on("ipcCall", async function (_ev: IpcMainEvent, payload) {
             recordSSOSession(args[0]);
             break;
 
+        case "getSecret":
+            try {
+                ret = await getSecretStore().getSecret(args[0]);
+            } catch (e) {
+                ret = null;
+            }
+            break;
+        case "saveSecret":
+            try {
+                ret = await getSecretStore().saveSecret(args[0], args[1]);
+            } catch (e) {
+                ret = null;
+            }
+            break;
+        case "destroySecret":
+            try {
+                ret = await getSecretStore().destroySecret(args[0]);
+            } catch (e) {}
+            break;
+
         case "getPickleKey":
             try {
                 ret = await keytar?.getPassword("element.io", `${args[0]}|${args[1]}`);

src/secrets.ts

@@ -0,0 +1,81 @@
+/*
+Copyright 2023 New Vector Ltd
+
+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 SafeStorage, safeStorage } from "electron";
+import Store from "electron-store";
+
+/**
+ * Save secrets on a local machine.
+ * These secrets are associated with a local machine user, not an Element user.
+ * CAUTION: They are not cleared when a user logs out of Element.
+ */
+interface SecretStore {
+    saveSecret(name: string, value: string): Promise<string | null>;
+    getSecret(name: string): Promise<string | null>;
+    destroySecret(name: string): Promise<void>;
+}
+
+class SafeStorageSecretStore implements SecretStore {
+    store: Store<Record<string, string>>;
+
+    public constructor(public readonly safeStorage: SafeStorage) {
+        // This uses its own store because these secrets should persist even on
+        // logout/login since security is ensured through OS-based authentication.
+        // Therefore, the security model is different from global.store
+        this.store = new Store<Record<string, string>>({
+            name: "safestorage",
+            schema: {
+                // $schema applies to root object
+                $schema: {
+                    type: "object",
+                    additionalProperties: { type: "string" }
+                }
+            },
+        });
+    }
+
+    public async saveSecret(name: string, value: string): Promise<string | null> {
+        this.store.set(name, this.safeStorage.encryptString(value).toString("base64"));
+        return await this.getSecret(name);
+    }
+    public async getSecret(name: string): Promise<string | null> {
+        return this.safeStorage.decryptString(Buffer.from(this.store.get(name) as string, "base64"));
+    }
+    public async destroySecret(name: string): Promise<void> {
+        this.store.delete(name);
+    }
+}
+
+class NullSecretStore implements SecretStore {
+    public async saveSecret(): Promise<string | null> { return null; }
+    public async getSecret(): Promise<string | null> { return null; }
+    public async destroySecret(): Promise<void> { }
+}
+
+function createSecretStore(): SecretStore {
+    if (safeStorage.isEncryptionAvailable() && safeStorage.getSelectedStorageBackend() !== "basic_text") {
+        return new SafeStorageSecretStore(safeStorage);
+    }
+    return new NullSecretStore();
+}
+
+let secretStore: SecretStore | null = null;
+export function getSecretStore(): SecretStore {
+    if (!secretStore) {
+        secretStore = createSecretStore();
+    }
+    return secretStore;
+}