85 lines
2.3 KiB
TypeScript
85 lines
2.3 KiB
TypeScript
import {
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buildCommand,
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buildError,
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Command,
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parseCommand,
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} from "./commandbuilder.ts";
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import { Device } from "./device.ts";
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function toHex(data: Uint8Array): string {
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return Array.from(data).map((b) => b.toString(16)).join("");
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}
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async function generateHMAC(key: string, message: string) {
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const encoder = new TextEncoder();
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const keyData = encoder.encode(key);
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const messageData = encoder.encode(message);
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const cryptoKey = await crypto.subtle.importKey(
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"raw",
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keyData,
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{ name: "HMAC", hash: { name: "SHA-256" } },
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false,
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["sign"],
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);
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const signature = await crypto.subtle.sign(
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"HMAC",
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cryptoKey,
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messageData,
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);
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return toHex(new Uint8Array(signature));
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}
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export class Authentication {
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_socket: WebSocket;
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_encoder: TextEncoder;
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nonce: string;
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device: Device | undefined;
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signature: string | undefined;
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constructor(socket: WebSocket) {
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this._socket = socket;
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this._encoder = new TextEncoder();
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this.nonce = toHex(crypto.getRandomValues(new Uint8Array(32)));
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}
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async authenticate(message: Command) { // ugh, js doesn't have async constructors, hence the seeprate init function.
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if (
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message.d == undefined || !("id" in message.d) ||
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typeof (message.d.id) !== "string" || !(message.d.id in Device.devices)
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) {
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this._socket.send(buildError(1, "Invalid packet. Missing ID"));
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this._socket.close();
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return;
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}
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this._socket.addEventListener("message", (msg) => this._validate(msg));
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this.device = Device.devices[message.d.id];
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this.signature = await generateHMAC(this.device.password, this.nonce);
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this._socket.send(
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buildCommand("auth_nonce", { nonce: this.nonce }),
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);
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}
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_validate(msg: MessageEvent<any>) {
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if (!this.device || !this.signature) return;
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const parsed = parseCommand(msg.data);
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if (
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parsed === null || parsed.c !== "auth_validate" ||
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parsed.d === undefined || !("signature" in parsed.d)
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) return;
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if (this.signature !== parsed.d.signature) {
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this._socket.send(buildError(2, "Invalid signature."));
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this._socket.close;
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return;
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}
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this._socket.send(buildCommand("auth_ok"));
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this.device?.connect(this._socket);
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this._socket.removeEventListener("message", this._validate);
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}
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}
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