Rust implementation of getEncryptionInfoForEvent

spec/unit/rust-crypto/rust-crypto.spec.ts

@@ -30,6 +30,7 @@ import {
     IHttpOpts,
     IToDeviceEvent,
     MatrixClient,
+    MatrixEvent,
     MatrixHttpApi,
     TypedEventEmitter,
 } from "../../../src";
@@ -38,7 +39,13 @@ import { CryptoBackend } from "../../../src/common-crypto/CryptoBackend";
 import { IEventDecryptionResult } from "../../../src/@types/crypto";
 import { OutgoingRequestProcessor } from "../../../src/rust-crypto/OutgoingRequestProcessor";
 import { ServerSideSecretStorage } from "../../../src/secret-storage";
-import { CryptoCallbacks, ImportRoomKeysOpts, VerificationRequest } from "../../../src/crypto-api";
+import {
+    CryptoCallbacks,
+    EventShieldColour,
+    EventShieldReason,
+    ImportRoomKeysOpts,
+    VerificationRequest,
+} from "../../../src/crypto-api";
 import * as testData from "../../test-utils/test-data";
 import { defer } from "../../../src/utils";
 
@@ -373,6 +380,111 @@ describe("RustCrypto", () => {
         });
     });
 
+    describe(".getEncryptionInfoForEvent", () => {
+        let rustCrypto: RustCrypto;
+        let olmMachine: Mocked<RustSdkCryptoJs.OlmMachine>;
+
+        beforeEach(() => {
+            olmMachine = {
+                getRoomEventEncryptionInfo: jest.fn(),
+            } as unknown as Mocked<RustSdkCryptoJs.OlmMachine>;
+            rustCrypto = new RustCrypto(
+                olmMachine,
+                {} as MatrixClient["http"],
+                TEST_USER,
+                TEST_DEVICE_ID,
+                {} as ServerSideSecretStorage,
+                {} as CryptoCallbacks,
+            );
+        });
+
+        afterEach(() => {
+            jest.restoreAllMocks();
+        });
+
+        async function makeEncryptedEvent(): Promise<MatrixEvent> {
+            const encryptedEvent = mkEvent({
+                event: true,
+                type: "m.room.encrypted",
+                content: { algorithm: "fake_alg" },
+                room: "!room:id",
+            });
+            encryptedEvent.event.event_id = "$event:id";
+            const mockCryptoBackend = {
+                decryptEvent: () =>
+                    ({
+                        clearEvent: { content: { body: "1234" } },
+                    } as unknown as IEventDecryptionResult),
+            } as unknown as CryptoBackend;
+            await encryptedEvent.attemptDecryption(mockCryptoBackend);
+            return encryptedEvent;
+        }
+
+        it("should handle unencrypted events", async () => {
+            const event = mkEvent({ event: true, type: "m.room.message", content: { body: "xyz" } });
+            const res = await rustCrypto.getEncryptionInfoForEvent(event);
+            expect(res).toBe(null);
+            expect(olmMachine.getRoomEventEncryptionInfo).not.toHaveBeenCalled();
+        });
+
+        it("passes the event into the OlmMachine", async () => {
+            const encryptedEvent = await makeEncryptedEvent();
+            const res = await rustCrypto.getEncryptionInfoForEvent(encryptedEvent);
+            expect(res).toBe(null);
+            expect(olmMachine.getRoomEventEncryptionInfo).toHaveBeenCalledTimes(1);
+            const [passedEvent, passedRoom] = olmMachine.getRoomEventEncryptionInfo.mock.calls[0];
+            expect(passedRoom.toString()).toEqual("!room:id");
+            expect(JSON.parse(passedEvent)).toStrictEqual(
+                expect.objectContaining({
+                    event_id: "$event:id",
+                }),
+            );
+        });
+
+        it.each([
+            [RustSdkCryptoJs.ShieldColor.None, EventShieldColour.NONE],
+            [RustSdkCryptoJs.ShieldColor.Grey, EventShieldColour.GREY],
+            [RustSdkCryptoJs.ShieldColor.Red, EventShieldColour.RED],
+        ])("gets the right shield color (%i)", async (rustShield, expectedShield) => {
+            const mockEncryptionInfo = {
+                shieldState: jest.fn().mockReturnValue({ color: rustShield, message: null }),
+            } as unknown as RustSdkCryptoJs.EncryptionInfo;
+            olmMachine.getRoomEventEncryptionInfo.mockResolvedValue(mockEncryptionInfo);
+
+            const res = await rustCrypto.getEncryptionInfoForEvent(await makeEncryptedEvent());
+            expect(mockEncryptionInfo.shieldState).toHaveBeenCalledWith(false);
+            expect(res).not.toBe(null);
+            expect(res!.shieldColour).toEqual(expectedShield);
+        });
+
+        it.each([
+            [null, null],
+            ["Encrypted by an unverified user.", EventShieldReason.UNVERIFIED_IDENTITY],
+            ["Encrypted by a device not verified by its owner.", EventShieldReason.UNSIGNED_DEVICE],
+            [
+                "The authenticity of this encrypted message can't be guaranteed on this device.",
+                EventShieldReason.AUTHENTICITY_NOT_GUARANTEED,
+            ],
+            ["Encrypted by an unknown or deleted device.", EventShieldReason.UNKNOWN_DEVICE],
+            ["bloop", EventShieldReason.UNKNOWN],
+        ])("gets the right shield reason (%s)", async (rustReason, expectedReason) => {
+            // suppress the warning from the unknown shield reason
+            jest.spyOn(console, "warn").mockImplementation(() => {});
+
+            const mockEncryptionInfo = {
+                shieldState: jest
+                    .fn()
+                    .mockReturnValue({ color: RustSdkCryptoJs.ShieldColor.None, message: rustReason }),
+            } as unknown as RustSdkCryptoJs.EncryptionInfo;
+            olmMachine.getRoomEventEncryptionInfo.mockResolvedValue(mockEncryptionInfo);
+
+            const res = await rustCrypto.getEncryptionInfoForEvent(await makeEncryptedEvent());
+            expect(mockEncryptionInfo.shieldState).toHaveBeenCalledWith(false);
+            expect(res).not.toBe(null);
+            expect(res!.shieldReason).toEqual(expectedReason);
+        });
+    });
+
     describe("get|setTrustCrossSignedDevices", () => {
         let rustCrypto: RustCrypto;
 

src/rust-crypto/rust-crypto.ts

@@ -42,6 +42,7 @@ import {
     DeviceVerificationStatus,
     EventEncryptionInfo,
     EventShieldColour,
+    EventShieldReason,
     GeneratedSecretStorageKey,
     ImportRoomKeyProgressData,
     ImportRoomKeysOpts,
@@ -788,10 +789,7 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
      * Implementation of {@link CryptoApi.getEncryptionInfoForEvent}.
      */
     public async getEncryptionInfoForEvent(event: MatrixEvent): Promise<EventEncryptionInfo | null> {
-        return {
-            shieldColour: EventShieldColour.NONE,
-            shieldReason: null,
-        };
+        return this.eventDecryptor.getEncryptionInfoForEvent(event);
     }
 
     /**
@@ -1484,14 +1482,7 @@ class EventDecryptor {
 
         try {
             const res = (await this.olmMachine.decryptRoomEvent(
-                JSON.stringify({
-                    event_id: event.getId(),
-                    type: event.getWireType(),
-                    sender: event.getSender(),
-                    state_key: event.getStateKey(),
-                    content: event.getWireContent(),
-                    origin_server_ts: event.getTs(),
-                }),
+                stringifyEvent(event),
                 new RustSdkCryptoJs.RoomId(event.getRoomId()!),
             )) as RustSdkCryptoJs.DecryptedRoomEvent;
 
@@ -1549,6 +1540,20 @@ class EventDecryptor {
         }
     }
 
+    public async getEncryptionInfoForEvent(event: MatrixEvent): Promise<EventEncryptionInfo | null> {
+        if (!event.getClearContent()) {
+            // not successfully decrypted
+            return null;
+        }
+
+        const encryptionInfo = await this.olmMachine.getRoomEventEncryptionInfo(
+            stringifyEvent(event),
+            new RustSdkCryptoJs.RoomId(event.getRoomId()!),
+        );
+
+        return rustEncryptionInfoToJsEncryptionInfo(encryptionInfo);
+    }
+
     /**
      * Look for events which are waiting for a given megolm session
      *
@@ -1606,6 +1611,61 @@ class EventDecryptor {
     }
 }
 
+function stringifyEvent(event: MatrixEvent): string {
+    return JSON.stringify({
+        event_id: event.getId(),
+        type: event.getWireType(),
+        sender: event.getSender(),
+        state_key: event.getStateKey(),
+        content: event.getWireContent(),
+        origin_server_ts: event.getTs(),
+    });
+}
+
+function rustEncryptionInfoToJsEncryptionInfo(
+    encryptionInfo: RustSdkCryptoJs.EncryptionInfo | undefined,
+): EventEncryptionInfo | null {
+    if (encryptionInfo === undefined) {
+        // not decrypted here
+        return null;
+    }
+
+    // TODO: use strict shield semantics.
+    const shieldState = encryptionInfo.shieldState(false);
+
+    let shieldColour: EventShieldColour;
+    switch (shieldState.color) {
+        case RustSdkCryptoJs.ShieldColor.Grey:
+            shieldColour = EventShieldColour.GREY;
+            break;
+        case RustSdkCryptoJs.ShieldColor.None:
+            shieldColour = EventShieldColour.NONE;
+            break;
+        default:
+            shieldColour = EventShieldColour.RED;
+    }
+
+    let shieldReason: EventShieldReason | null;
+    if (shieldState.message === null) {
+        shieldReason = null;
+    } else if (shieldState.message === "Encrypted by an unverified user.") {
+        shieldReason = EventShieldReason.UNVERIFIED_IDENTITY;
+    } else if (shieldState.message === "Encrypted by a device not verified by its owner.") {
+        shieldReason = EventShieldReason.UNSIGNED_DEVICE;
+    } else if (
+        shieldState.message === "The authenticity of this encrypted message can't be guaranteed on this device."
+    ) {
+        shieldReason = EventShieldReason.AUTHENTICITY_NOT_GUARANTEED;
+    } else if (shieldState.message === "Encrypted by an unknown or deleted device.") {
+        shieldReason = EventShieldReason.UNKNOWN_DEVICE;
+    } else {
+        logger.warn(`Unknown shield state message '${shieldState.message}'`);
+        shieldReason = EventShieldReason.UNKNOWN;
+    }
+
+    return { shieldColour, shieldReason };
+}
+
 type RustCryptoEvents =
     | CryptoEvent.VerificationRequestReceived
     | CryptoEvent.UserTrustStatusChanged