workadventure/back/src/Services/MapFetcher.ts
2021-11-24 16:20:07 +01:00

71 lines
2.8 KiB
TypeScript

import Axios from "axios";
import ipaddr from "ipaddr.js";
import { Resolver } from "dns";
import { promisify } from "util";
import { LocalUrlError } from "./LocalUrlError";
import { ITiledMap } from "@workadventure/tiled-map-type-guard";
import { isTiledMap } from "@workadventure/tiled-map-type-guard/dist";
import { STORE_VARIABLES_FOR_LOCAL_MAPS } from "../Enum/EnvironmentVariable";
class MapFetcher {
async fetchMap(mapUrl: string): Promise<ITiledMap> {
// Before trying to make the query, let's verify the map is actually on the open internet (and not a local test map)
if ((await this.isLocalUrl(mapUrl)) && !STORE_VARIABLES_FOR_LOCAL_MAPS) {
throw new LocalUrlError('URL for map "' + mapUrl + '" targets a local map');
}
// Note: mapUrl is provided by the client. A possible attack vector would be to use a rogue DNS server that
// returns local URLs. Alas, Axios cannot pin a URL to a given IP. So "isLocalUrl" and Axios.get could potentially
// target to different servers (and one could trick Axios.get into loading resources on the internal network
// despite isLocalUrl checking that.
// We can deem this problem not that important because:
// - We make sure we are only passing "GET" requests
// - The result of the query is never displayed to the end user
const res = await Axios.get(mapUrl, {
maxContentLength: 50 * 1024 * 1024, // Max content length: 50MB. Maps should not be bigger
timeout: 10000, // Timeout after 10 seconds
});
if (!isTiledMap(res.data)) {
//TODO fixme
//throw new Error("Invalid map format for map " + mapUrl);
console.error("Invalid map format for map " + mapUrl);
}
return res.data;
}
/**
* Returns true if the domain name is localhost of *.localhost
* Returns true if the domain name resolves to an IP address that is "private" (like 10.x.x.x or 192.168.x.x)
*
* @private
*/
async isLocalUrl(url: string): Promise<boolean> {
const urlObj = new URL(url);
if (urlObj.hostname === "localhost" || urlObj.hostname.endsWith(".localhost")) {
return true;
}
let addresses = [];
if (!ipaddr.isValid(urlObj.hostname)) {
const resolver = new Resolver();
addresses = await promisify(resolver.resolve).bind(resolver)(urlObj.hostname);
} else {
addresses = [urlObj.hostname];
}
for (const address of addresses) {
const addr = ipaddr.parse(address);
if (addr.range() !== "unicast") {
return true;
}
}
return false;
}
}
export const mapFetcher = new MapFetcher();