refactor: improve Bedrock error handling and validation

lib/bedrock.js

@@ -10,6 +10,7 @@ import crypto from "node:crypto";
 
 const MAGIC = "00ffff00fefefefefdfdfdfd12345678";
 const START_TIME = new Date().getTime();
+const UNCONNECTED_PONG = 0x1c;
 
 /**
  * Creates an Unconnected Ping packet.
@@ -30,12 +31,25 @@ const createUnconnectedPingFrame = (timestamp) => {
  * Extract Modt from Unconnected Pong Packet and convert to an object
  * @param {Buffer} unconnectedPongPacket
  * @returns {Object}
+ * @throws {Error} If packet is malformed or invalid
  * @see {@link https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Raknet_Protocol#Unconnected_Pong}
  */
 const extractModt = (unconnectedPongPacket) => {
-	// Skip everything to Modt
+	if (
+		!Buffer.isBuffer(unconnectedPongPacket) ||
+		unconnectedPongPacket.length < 35
+	) {
+		throw new Error("Invalid pong packet");
+	}
+
 	const offset = 33;
 	const length = unconnectedPongPacket.readUInt16BE(offset);
+
+	// Check for buffer bounds
+	if (offset + 2 + length > unconnectedPongPacket.length) {
+		throw new Error("Malformed pong packet");
+	}
+
 	let modt = unconnectedPongPacket.toString(
 		"utf-8",
 		offset + 2,
@@ -43,6 +57,12 @@ const extractModt = (unconnectedPongPacket) => {
 	);
 
 	const components = modt.split(";");
+
+	// Validate required components
+	if (components.length < 9) {
+		throw new Error("Invalid MODT format");
+	}
+
 	const parsedComponents = {
 		edition: components[0],
 		name: components[1],
@@ -109,20 +129,23 @@ const ping = (host, port = 19132, cb, timeout = 5000) => {
 	}
 
 	socket.on("message", (pongPacket) => {
-		const id = pongPacket[0];
+		if (!Buffer.isBuffer(pongPacket) || pongPacket.length === 0) {
+			handleError(new Error("Invalid packet received"));
+			return;
+		}
 
-		switch (id) {
-			case 0x1c: {
+		const id = pongPacket[0];
+		if (id !== UNCONNECTED_PONG) {
+			handleError(new Error(`Unexpected packet ID: 0x${id.toString(16)}`));
+			return;
+		}
+
+		try {
 			const modtObject = extractModt(pongPacket);
 			closeSocket();
 			cb(modtObject, null);
-				break;
-			}
-
-			default: {
-				handleError(new Error("Received unexpected packet"));
-				break;
-			}
+		} catch (err) {
+			handleError(err);
 		}
 	});
 

lib/varint.js

@@ -27,7 +27,7 @@ const varint = {
 			buf.writeUInt8(byte | 0x80, written++);
 		}
 
-		return buf.slice(0, written);
+		return buf.subarray(0, written);
 	},
 
 	/**

types/lib/bedrock.d.ts

@@ -1,10 +1,10 @@
 /**
- * @param port The server port.
- * @param timeout The read/write socket timeout.
+ * @param port The server port (1-65535).
+ * @param timeout The read/write socket timeout in milliseconds.
  */
 export type BedrockPingOptions = {
-    port?: number;
-    timeout?: number;
+	port?: number & { _brand: "Port" }; // 1-65535
+	timeout?: number & { _brand: "Timeout" }; // > 0
 };
 
 export type BedrockPingResponse = {
@@ -26,8 +26,6 @@ export type BedrockPingResponse = {
 /**
  * Asynchronously ping Minecraft Bedrock server.
  *
- * The optional `options` argument can be an object with a `ping` (default is `19132`) or/and `timeout` (default is `5000`) property.
- * 
  * @param host The Bedrock server address.
  * @param options The configuration for pinging Minecraft Bedrock server.
  *
@@ -41,13 +39,23 @@ export type BedrockPingResponse = {
  * The resulting output will resemble:
  * ```console
  * {
- *   version: { name: 'Mineplex', protocol: '475' },
- *   players: { max: '5207', online: '5206' },
- *   description: ' New Costumes',
- *   gamemode: 'Survival'
+ *   edition: "MCPE",
+ *   name: "Mineplex",
+ *   version: {
+ *     protocolVersion: 475,
+ *     minecraftVersion: "1.18.0"
+ *   },
+ *   players: {
+ *     online: 5206,
+ *     max: 5207
+ *   },
+ *   serverId: "12345678",
+ *   mapName: "Lobby",
+ *   gameMode: "Survival"
  * }
  * ```
- * @see [source](https://github.com/minescope/mineping/blob/915edbec9c9ad811459458600af3531ec0836911/lib/bedrock.js#L204)
  */
-export function pingBedrock(host: string, options?: BedrockPingOptions): Promise<BedrockPingResponse>;
-
+export function pingBedrock(
+	host: string,
+	options?: BedrockPingOptions
+): Promise<BedrockPingResponse>;