upstream-rocketchat/apps/meteor/server/lib/e2e/functions/resetRoomKey.ts

import type { ISubscription, IUser, IRoom } from '@rocket.chat/core-typings';
import { Rooms, Subscriptions, Users } from '@rocket.chat/models';
import type { AnyBulkWriteOperation } from 'mongodb';

import { notifyOnRoomChanged, notifyOnSubscriptionChanged } from '../../notifyListener';

export async function resetRoomKey(roomId: string, userId: string, newRoomKey: string, newRoomKeyId: string) {
	const user = await Users.findOneById<Pick<IUser, 'e2e'>>(userId, { projection: { e2e: 1 } });
	if (!user) {
		throw new Error('error-user-not-found');
	}

	if (!user.e2e?.private_key || !user.e2e?.public_key) {
		throw new Error('error-user-has-no-keys');
	}

	const room = await Rooms.findOneById<Pick<IRoom, 'e2eKeyId'>>(roomId, { projection: { e2eKeyId: 1 } });
	if (!room) {
		throw new Error('error-room-not-found');
	}

	if (!room.e2eKeyId) {
		throw new Error('error-room-not-encrypted');
	}

	// We will update the subs of everyone who has a key for the room. For the ones that don't have, we will do nothing
	const notifySubs = [];
	const updateOps: AnyBulkWriteOperation<ISubscription>[] = [];
	const e2eQueue: IRoom['usersWaitingForE2EKeys'] = [];

	for await (const sub of Subscriptions.find({
		rid: roomId,
		$or: [{ E2EKey: { $exists: true } }, { E2ESuggestedKey: { $exists: true } }],
	})) {
		// This replicates the oldRoomKeys array modifications allowing us to have the changes locally without finding them again
		// which allows for quicker notifying
		const keys = replicateMongoSlice(room.e2eKeyId, sub);
		delete sub.E2ESuggestedKey;
		delete sub.E2EKey;
		delete sub.suggestedOldRoomKeys;

		const updateSet = {
			$set: {
				...(keys && { oldRoomKeys: keys }),
			},
		};
		updateOps.push({
			updateOne: {
				filter: { _id: sub._id },
				update: {
					$unset: { E2EKey: 1, E2ESuggestedKey: 1, suggestedOldRoomKeys: 1 },
					...(Object.keys(updateSet.$set).length && updateSet),
				},
			},
		});

		if (userId !== sub.u._id) {
			// Avoid notifying requesting user as notify will happen at the end
			notifySubs.push({
				...sub,
				...(keys && { oldRoomKeys: keys }),
			});

			// This is for allowing the key distribution process to start inmediately
			pushToLimit(e2eQueue, { userId: sub.u._id, ts: new Date() });
		}

		if (updateOps.length >= 100) {
			await writeAndNotify(updateOps, notifySubs);
		}
	}

	if (updateOps.length > 0) {
		await writeAndNotify(updateOps, notifySubs);
	}

	// after the old keys have been moved to the new prop, store room key on room + the e2e queue so key can be exchanged
	// todo move to model method
	const roomResult = await Rooms.resetRoomKeyAndSetE2EEQueueByRoomId(roomId, newRoomKeyId, e2eQueue);
	// And set the new key to the user that called the func
	const result = await Subscriptions.setE2EKeyByUserIdAndRoomId(userId, roomId, newRoomKey);

	if (result) {
		void notifyOnSubscriptionChanged(result);
	}
	if (roomResult) {
		void notifyOnRoomChanged(roomResult);
	}
}

export function pushToLimit(
	arr: NonNullable<IRoom['usersWaitingForE2EKeys']>,
	item: NonNullable<IRoom['usersWaitingForE2EKeys']>[number],
	limit = 50,
) {
	if (arr.length < limit) {
		arr.push(item);
	}
}

async function writeAndNotify(updateOps: AnyBulkWriteOperation<ISubscription>[], notifySubs: ISubscription[]) {
	await Subscriptions.col.bulkWrite([...updateOps]);
	notifySubs.forEach((sub) => {
		void notifyOnSubscriptionChanged(sub);
	});
	notifySubs.length = 0;
	updateOps.length = 0;
}

export function replicateMongoSlice(keyId: string, sub: ISubscription) {
	if (!sub.E2EKey) {
		return;
	}

	if (!sub.oldRoomKeys) {
		return [{ e2eKeyId: keyId, ts: new Date(), E2EKey: sub.E2EKey }];
	}

	const sortedKeys = sub.oldRoomKeys.toSorted((a, b) => b.ts.getTime() - a.ts.getTime());
	sortedKeys.unshift({ e2eKeyId: keyId, ts: new Date(), E2EKey: sub.E2EKey });

	return sortedKeys.slice(0, 10);
}