Store USK and SSK locally

package.json

@@ -78,7 +78,9 @@
     "eslint-plugin-babel": "^5.3.0",
     "eslint-plugin-jest": "^23.0.4",
     "exorcist": "^1.0.1",
+    "fake-indexeddb": "^3.0.0",
     "jest": "^24.9.0",
+    "jest-localstorage-mock": "^2.4.0",
     "jsdoc": "^3.5.5",
     "matrix-mock-request": "^1.2.3",
     "olm": "https://packages.matrix.org/npm/olm/olm-3.1.4.tgz",

spec/unit/crypto/CrossSigningInfo.spec.js

@@ -0,0 +1,246 @@
+/*
+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 '../../olm-loader';
+import {
+    CrossSigningInfo,
+    createCryptoStoreCacheCallbacks,
+} from '../../../src/crypto/CrossSigning';
+import {
+    IndexedDBCryptoStore,
+} from '../../../src/crypto/store/indexeddb-crypto-store';
+import {MemoryCryptoStore} from '../../../src/crypto/store/memory-crypto-store';
+import 'fake-indexeddb/auto';
+import 'jest-localstorage-mock';
+
+const userId = "@alice:example.com";
+
+// Private key for tests only
+const testKey = new Uint8Array([
+    0xda, 0x5a, 0x27, 0x60, 0xe3, 0x3a, 0xc5, 0x82,
+    0x9d, 0x12, 0xc3, 0xbe, 0xe8, 0xaa, 0xc2, 0xef,
+    0xae, 0xb1, 0x05, 0xc1, 0xe7, 0x62, 0x78, 0xa6,
+    0xd7, 0x1f, 0xf8, 0x2c, 0x51, 0x85, 0xf0, 0x1d,
+]);
+
+const types = [
+    { type: "master", shouldCache: false },
+    { type: "self_signing", shouldCache: true },
+    { type: "user_signing", shouldCache: true },
+    { type: "invalid", shouldCache: false },
+];
+
+const badKey = Uint8Array.from(testKey);
+badKey[0] ^= 1;
+
+const masterKeyPub = "nqOvzeuGWT/sRx3h7+MHoInYj3Uk2LD/unI9kDYcHwk";
+
+describe("CrossSigningInfo.getCrossSigningKey", function() {
+    if (!global.Olm) {
+        console.warn('Not running megolm backup unit tests: libolm not present');
+        return;
+    }
+
+    beforeAll(function() {
+        return global.Olm.init();
+    });
+
+    it("should throw if no callback is provided", async () => {
+        const info = new CrossSigningInfo(userId);
+        await expect(info.getCrossSigningKey("master")).rejects.toThrow();
+    });
+
+    it.each(types)("should throw if the callback returns falsey",
+                   async ({type, shouldCache}) => {
+        const info = new CrossSigningInfo(userId, {
+            getCrossSigningKey: () => false,
+        });
+        await expect(info.getCrossSigningKey(type)).rejects.toThrow("falsey");
+    });
+
+    it("should throw if the expected key doesn't come back", async () => {
+        const info = new CrossSigningInfo(userId, {
+            getCrossSigningKey: () => masterKeyPub,
+        });
+        await expect(info.getCrossSigningKey("master", "")).rejects.toThrow();
+    });
+
+    it("should return a key from its callback", async () => {
+        const info = new CrossSigningInfo(userId, {
+            getCrossSigningKey: () => testKey,
+        });
+        const [pubKey, ab] = await info.getCrossSigningKey("master", masterKeyPub);
+        expect(pubKey).toEqual(masterKeyPub);
+        expect(ab).toEqual({a: 106712, b: 106712});
+    });
+
+    it.each(types)("should request a key from the cache callback (if set)" +
+                   " and does not call app if one is found" +
+                   " %o",
+                   async ({ type, shouldCache }) => {
+        const getCrossSigningKey = jest.fn().mockImplementation(() => {
+            if (shouldCache) {
+                return Promise.reject(new Error("Regular callback called"));
+            } else {
+                return Promise.resolve(testKey);
+            }
+        });
+        const getCrossSigningKeyCache = jest.fn().mockResolvedValue(testKey);
+        const info = new CrossSigningInfo(
+            userId,
+            { getCrossSigningKey },
+            { getCrossSigningKeyCache },
+        );
+        const [pubKey] = await info.getCrossSigningKey(type, masterKeyPub);
+        expect(pubKey).toEqual(masterKeyPub);
+        expect(getCrossSigningKeyCache.mock.calls.length).toBe(shouldCache ? 1 : 0);
+        if (shouldCache) {
+            expect(getCrossSigningKeyCache.mock.calls[0][0]).toBe(type);
+        }
+    });
+
+    it.each(types)("should store a key with the cache callback (if set)",
+                   async ({ type, shouldCache }) => {
+        const getCrossSigningKey = jest.fn().mockResolvedValue(testKey);
+        const storeCrossSigningKeyCache = jest.fn().mockResolvedValue(undefined);
+        const info = new CrossSigningInfo(
+            userId,
+            { getCrossSigningKey },
+            { storeCrossSigningKeyCache },
+        );
+        const [pubKey] = await info.getCrossSigningKey(type, masterKeyPub);
+        expect(pubKey).toEqual(masterKeyPub);
+        expect(storeCrossSigningKeyCache.mock.calls.length).toEqual(shouldCache ? 1 : 0);
+        if (shouldCache) {
+            expect(storeCrossSigningKeyCache.mock.calls[0][0]).toBe(type);
+            expect(storeCrossSigningKeyCache.mock.calls[0][1]).toBe(testKey);
+        }
+    });
+
+    it.each(types)("does not store a bad key to the cache",
+                   async ({ type, shouldCache }) => {
+        const getCrossSigningKey = jest.fn().mockResolvedValue(badKey);
+        const storeCrossSigningKeyCache = jest.fn().mockResolvedValue(undefined);
+        const info = new CrossSigningInfo(
+            userId,
+            { getCrossSigningKey },
+            { storeCrossSigningKeyCache },
+        );
+        await expect(info.getCrossSigningKey(type, masterKeyPub)).rejects.toThrow();
+        expect(storeCrossSigningKeyCache.mock.calls.length).toEqual(0);
+    });
+
+    it.each(types)("does not store a value to the cache if it came from the cache",
+        async ({ type, shouldCache }) => {
+        const getCrossSigningKey = jest.fn().mockImplementation(() => {
+            if (shouldCache) {
+                return Promise.reject(new Error("Regular callback called"));
+            } else {
+                return Promise.resolve(testKey);
+            }
+        });
+        const getCrossSigningKeyCache = jest.fn().mockResolvedValue(testKey);
+        const storeCrossSigningKeyCache = jest.fn().mockRejectedValue(
+            new Error("Tried to store a value from cache"),
+        );
+        const info = new CrossSigningInfo(
+            userId,
+            { getCrossSigningKey },
+            { getCrossSigningKeyCache, storeCrossSigningKeyCache },
+        );
+        expect(storeCrossSigningKeyCache.mock.calls.length).toBe(0);
+        const [pubKey] = await info.getCrossSigningKey(type, masterKeyPub);
+        expect(pubKey).toEqual(masterKeyPub);
+    });
+
+    it.each(types)("requests a key from the cache callback (if set) and then calls app" +
+        " if one is not found", async ({ type, shouldCache }) => {
+        const getCrossSigningKey = jest.fn().mockResolvedValue(testKey);
+        const getCrossSigningKeyCache = jest.fn().mockResolvedValue(undefined);
+        const storeCrossSigningKeyCache = jest.fn();
+        const info = new CrossSigningInfo(
+            userId,
+            { getCrossSigningKey },
+            { getCrossSigningKeyCache, storeCrossSigningKeyCache },
+        );
+        const [pubKey] = await info.getCrossSigningKey(type, masterKeyPub);
+        expect(pubKey).toEqual(masterKeyPub);
+        expect(getCrossSigningKey.mock.calls.length).toBe(1);
+        expect(getCrossSigningKeyCache.mock.calls.length).toBe(shouldCache ? 1 : 0);
+
+        /* Also expect that the cache gets updated */
+        expect(storeCrossSigningKeyCache.mock.calls.length).toBe(shouldCache ? 1 : 0);
+    });
+
+    it.each(types)("requests a key from the cache callback (if set) and then" +
+        " calls app if that key doesn't match", async ({ type, shouldCache }) => {
+        const getCrossSigningKey = jest.fn().mockResolvedValue(testKey);
+        const getCrossSigningKeyCache = jest.fn().mockResolvedValue(badKey);
+        const storeCrossSigningKeyCache = jest.fn();
+        const info = new CrossSigningInfo(
+            userId,
+            { getCrossSigningKey },
+            { getCrossSigningKeyCache, storeCrossSigningKeyCache },
+        );
+        const [pubKey] = await info.getCrossSigningKey(type, masterKeyPub);
+        expect(pubKey).toEqual(masterKeyPub);
+        expect(getCrossSigningKey.mock.calls.length).toBe(1);
+        expect(getCrossSigningKeyCache.mock.calls.length).toBe(shouldCache ? 1 : 0);
+
+        /* Also expect that the cache gets updated */
+        expect(storeCrossSigningKeyCache.mock.calls.length).toBe(shouldCache ? 1 : 0);
+    });
+});
+
+/*
+ * Note that MemoryStore is weird.  It's only used for testing - as far as I can tell,
+ * it's not possible to get one in normal execution unless you hack as we do here.
+ */
+describe.each([
+    ["IndexedDBCryptoStore",
+     () => new IndexedDBCryptoStore(global.indexedDB, "tests")],
+    ["LocalStorageCryptoStore",
+     () => new IndexedDBCryptoStore(undefined, "tests")],
+    ["MemoryCryptoStore", () => {
+        const store = new IndexedDBCryptoStore(undefined, "tests");
+        store._backendPromise = Promise.resolve(new MemoryCryptoStore());
+        return store;
+    }],
+])("CrossSigning > createCryptoStoreCacheCallbacks [%s]", function(name, dbFactory) {
+    let store;
+
+    beforeAll(() => {
+        store = dbFactory();
+    });
+
+    beforeEach(async () => {
+        await store.deleteAllData();
+    });
+
+    it("should cache data to the store and retrieves it", async () => {
+        const { getCrossSigningKeyCache, storeCrossSigningKeyCache } =
+          createCryptoStoreCacheCallbacks(store);
+        await storeCrossSigningKeyCache("master", testKey);
+
+        // If we've not saved anything, don't expect anything
+        // Definitely don't accidentally return the wrong key for the type
+        const nokey = await getCrossSigningKeyCache("self", "");
+        expect(nokey).toBeNull();
+
+        const key = await getCrossSigningKeyCache("master", "");
+        expect(key).toEqual(testKey);
+    });
+});

spec/unit/crypto/verification/verification_request.spec.js

@@ -120,7 +120,6 @@ async function distributeEvent(ownRequest, theirRequest, event) {
 }
 
 describe("verification request unit tests", function() {
-
     beforeAll(function() {
         setupWebcrypto();
     });

src/crypto/CrossSigning.js

@@ -23,6 +23,7 @@ limitations under the License.
 import {decodeBase64, encodeBase64, pkSign, pkVerify} from './olmlib';
 import {EventEmitter} from 'events';
 import {logger} from '../logger';
+import {IndexedDBCryptoStore} from '../crypto/store/indexeddb-crypto-store';
 
 function publicKeyFromKeyInfo(keyInfo) {
     // `keys` is an object with { [`ed25519:${pubKey}`]: pubKey }
@@ -40,8 +41,9 @@ export class CrossSigningInfo extends EventEmitter {
      * @param {string} userId the user that the information is about
      * @param {object} callbacks Callbacks used to interact with the app
      *     Requires getCrossSigningKey and saveCrossSigningKeys
+     * @param {object} cacheCallbacks Callbacks used to interact with the cache
      */
-    constructor(userId, callbacks) {
+    constructor(userId, callbacks, cacheCallbacks) {
         super();
 
         // you can't change the userId
@@ -50,6 +52,7 @@ export class CrossSigningInfo extends EventEmitter {
             value: userId,
         });
         this._callbacks = callbacks || {};
+        this._cacheCallbacks = cacheCallbacks || {};
         this.keys = {};
         this.firstUse = true;
     }
@@ -62,6 +65,8 @@ export class CrossSigningInfo extends EventEmitter {
      * @returns {Array} An array with [ public key, Olm.PkSigning ]
      */
     async getCrossSigningKey(type, expectedPubkey) {
+        const shouldCache = ["self_signing", "user_signing"].indexOf(type) >= 0;
+
         if (!this._callbacks.getCrossSigningKey) {
             throw new Error("No getCrossSigningKey callback supplied");
         }
@@ -70,22 +75,47 @@ export class CrossSigningInfo extends EventEmitter {
             expectedPubkey = this.getId(type);
         }
 
-        const privkey = await this._callbacks.getCrossSigningKey(type, expectedPubkey);
+        function validateKey(key) {
+            if (!key) return;
+            const signing = new global.Olm.PkSigning();
+            const gotPubkey = signing.init_with_seed(key);
+            if (gotPubkey === expectedPubkey) {
+                return [gotPubkey, signing];
+            }
+            signing.free();
+        }
+
+        let privkey;
+        if (this._cacheCallbacks.getCrossSigningKeyCache && shouldCache) {
+            privkey = await this._cacheCallbacks
+              .getCrossSigningKeyCache(type, expectedPubkey);
+        }
+
+        const cacheresult = validateKey(privkey);
+        if (cacheresult) {
+            return cacheresult;
+        }
+
+        privkey = await this._callbacks.getCrossSigningKey(type, expectedPubkey);
+        const result = validateKey(privkey);
+        if (result) {
+            if (this._cacheCallbacks.storeCrossSigningKeyCache && shouldCache) {
+                await this._cacheCallbacks.storeCrossSigningKeyCache(type, privkey);
+            }
+            return result;
+        }
+
+        /* No keysource even returned a key */
         if (!privkey) {
             throw new Error(
                 "getCrossSigningKey callback for " + type + " returned falsey",
             );
         }
-        const signing = new global.Olm.PkSigning();
-        const gotPubkey = signing.init_with_seed(privkey);
-        if (gotPubkey !== expectedPubkey) {
-            signing.free();
-            throw new Error(
-                "Key type " + type + " from getCrossSigningKey callback did not match",
-            );
-        } else {
-            return [gotPubkey, signing];
-        }
+
+        /* We got some keys from the keysource, but none of them were valid */
+        throw new Error(
+            "Key type " + type + " from getCrossSigningKey callback did not match",
+        );
     }
 
     static fromStorage(obj, userId) {
@@ -539,3 +569,28 @@ export class DeviceTrustLevel {
         return this._tofu;
     }
 }
+
+export function createCryptoStoreCacheCallbacks(store) {
+    return {
+        getCrossSigningKeyCache: function(type, _expectedPublicKey) {
+            return new Promise((resolve) => {
+                return store.doTxn(
+                    'readonly',
+                    [IndexedDBCryptoStore.STORE_ACCOUNT],
+                    (txn) => {
+                        store.getCrossSigningPrivateKey(txn, resolve, type);
+                    },
+                );
+            });
+        },
+        storeCrossSigningKeyCache: function(type, key) {
+            return store.doTxn(
+                'readwrite',
+                [IndexedDBCryptoStore.STORE_ACCOUNT],
+                (txn) => {
+                    store.storeCrossSigningPrivateKey(txn, type, key);
+                },
+            );
+        },
+    };
+}