fix(web): verify deletions against the signer and read crypto state afresh

web/src/core-bridge/worker/channelDataKeys.ts

@@ -37,13 +37,29 @@ export function attachDataKeys(session: ChannelSession, resource: SavedResource)
   };
 }
 type DataKeys = { state: CryptoState; keys: Record<string, string> };
-const pendingKeys = new Map<string, Promise<DataKeys>>();
-/** 同一空间同时发起的读取合并成一次请求 */
-export function readDataKeys(resource: SavedResource, session: ChannelSession): Promise<DataKeys> {
-  let task = pendingKeys.get(resource.id);
-  if (!task) { task = loadDataKeys(resource, session).finally(() => pendingKeys.delete(resource.id)); pendingKeys.set(resource.id, task); }
+const runningKeys = new Map<string, Promise<DataKeys>>();
+const queuedKeys = new Map<string, Promise<DataKeys>>();
+function startKeys(resource: SavedResource, session: ChannelSession): Promise<DataKeys> {
+  const task: Promise<DataKeys> = loadDataKeys(resource, session).finally(() => { if (runningKeys.get(resource.id) === task) runningKeys.delete(resource.id); });
+  runningKeys.set(resource.id, task);
   return task;
 }
+/**
+ * 读取空间的加密状态。fresh(默认)表示调用方刚发现本地缺对象或事件签名,需要一份比现在更新的结果:
+ * 已有请求在途时不能直接借用它(它可能在新对象登记之前就发出了),而是排在它后面再请求一次,同时到达的调用合并成这一次。
+ * 不要求最新(首次打开)的调用可以直接借用在途请求。
+ */
+export function readDataKeys(resource: SavedResource, session: ChannelSession, fresh = true): Promise<DataKeys> {
+  const running = runningKeys.get(resource.id);
+  if (!running) return startKeys(resource, session);
+  if (!fresh) return running;
+  let next = queuedKeys.get(resource.id);
+  if (!next) {
+    next = running.catch(() => undefined).then(() => { queuedKeys.delete(resource.id); return startKeys(resource, session); });
+    queuedKeys.set(resource.id, next);
+  }
+  return next;
+}
 /** 内存里的结果满足 enough 就复用,不满足再请求 */
 async function cachedKeys(resource: SavedResource, session: ChannelSession, enough: (data: DataKeys) => boolean): Promise<DataKeys> {
   const have = loaded.get(resource.id);
@@ -222,18 +238,20 @@ export async function verifyObjectDeletion(resource: SavedResource, session: Cha
   const eventId = fromBase64Url(deleted.eventId, 16); const manifestHash = fromBase64Url(object.event.manifestHash, 32);
   const signature = fromBase64Url(deleted.signature, 64); const certificate = fromBase64Url(deleted.deviceCertificateSignature, 64);
   if (!spaceId || !itemBytes || !eventId || !manifestHash || !signature || !certificate) return false;
+  // 撤回别人的消息时(空间主),删除事件由撤回者签名,不是作者;旧记录没有 signerAccount,按作者处理
+  const signer = deleted.signerAccount || object.authorAccount;
   const rootJwk = JSON.parse(deleted.signerRootPublicKey) as JsonWebKey;
   const deviceJwk = JSON.parse(deleted.signerDevicePublicKey) as JsonWebKey;
   const root = await importSigningPublicKey(rootJwk);
   const { unlockedAccount } = await import('./account'); const local = unlockedAccount();
-  if (object.authorAccount === local.username && local.profile.keys.signing
+  if (signer === local.username && local.profile.keys.signing
       && (rootJwk.x !== local.profile.keys.signing.publicKey.x || rootJwk.y !== local.profile.keys.signing.publicKey.y)) return false;
-  await pinSigningRoot(object.authorAccount, rootJwk);
-  if (!await verifyDeviceCertificate(object.authorAccount, deleted.signerDeviceId, deviceJwk, certificate, root)) return false;
+  await pinSigningRoot(signer, rootJwk);
+  if (!await verifyDeviceCertificate(signer, deleted.signerDeviceId, deviceJwk, certificate, root)) return false;
   const domain = object.domain;
   const expectedKind = domain === 'chat' ? 'chat.delete' : 'file.delete';
   if (deleted.kind !== expectedKind) return false;
-  const payload = contentEventPayload({ spaceId, channelId: object.channelId, username: object.authorAccount,
+  const payload = contentEventPayload({ spaceId, channelId: object.channelId, username: signer,
     deviceId: deleted.signerDeviceId, eventId, eventKind: expectedKind, domain, epoch: object.epoch,
     itemId: itemBytes, frameCount: object.event.frameCount, manifestHash });
   const deviceKey = await importSigningPublicKey(deviceJwk);