galvanic-corrosion/src/routes/user.ts

import { APIUtils, getSrcIpDefault, NoBody } from "../apiutils.ts";
// @ts-types = "npm:@types/express"
import express from "express";
import { User, UserTokenFormat } from "../data/users.ts";
import { Config } from "../config.ts";
import crypto from "node:crypto";
import Logging from "@proxnet/undead-logging";
import { decode } from "@gz/jwt";
import z from "zod";

const log = new Logging("UserRoute");

const config = Config.getConfig();

export const route = APIUtils.createRouter("/user");

interface AuthRequestSec {
    timestamp: number;
    nonce: string;
    server_id: string;
}

interface AuthRequestRoot {
    client_id: string;
    message: AuthRequestSec;
    signature: string;
    pubkey: string;
}

const AuthRequestSecSchema = z.object({
    timestamp: z.number(),
    nonce: z.string(),
    server_id: z.string(),
});

const AuthRequestRootSchema = z.object({
    client_id: z.string(),
    message: AuthRequestSecSchema,
    signature: z.string(),
    pubkey: z.string(),
});

const rateLimit = new APIUtils.RateLimiter(60, 1);

route.router.post("/auth",

    rateLimit.middle(),
    express.json(),
    APIUtils.validateRequestBody(AuthRequestRootSchema),

    async (
        rq: express.Request<NoBody, NoBody, AuthRequestRoot>,
        rs: express.Response,
    ) => {
        function authFailed(msg: string) {
            rs.json(APIUtils.genericResponseFormat(true, msg));
        }

        if (rq.body.message.server_id !== config.public.serverId) {
            log.w(
                `Auth request failed (serverId mismatch), config error?\n  given ID: '${rq.body.message.server_id}'\n  our ID: '${config.public.serverId}'`,
            );
            authFailed("Authentication request not intended for this server.");
            return;
        }

        try {
            const verify = crypto.createVerify("SHA256");
            verify.update(JSON.stringify(rq.body.message));
            verify.end();

            const publicKey = await crypto.subtle.importKey(
                "spki",
                (Uint8Array.from(atob(rq.body.pubkey), (c) => c.charCodeAt(0)))
                    .buffer,
                { name: "ECDSA", namedCurve: "P-256" },
                false,
                ["verify"],
            );
            const messageBytes = new TextEncoder().encode(
                JSON.stringify(rq.body.message),
            );
            const signatureBytes = Uint8Array.from(
                atob(rq.body.signature),
                (c) => c.charCodeAt(0),
            );
            const isValid = await crypto.subtle.verify(
                { name: "ECDSA", hash: "SHA-256" },
                publicKey,
                signatureBytes.buffer,
                messageBytes,
            );
            if (!isValid) {
                log.w(`Auth failed for clientId '${rq.body.client_id}'`);
                authFailed("Authentication request failed.");
                return;
            }
        } catch (err) {
            log.d(`Error when verifying auth request: ${err}`);
            authFailed("Authentication request failed.");
            return;
        }

        let user = new User(rq.body.client_id);
        if (!(await user.exists())) {
            const obj = await User.init({
                client_id: rq.body.client_id,
                pubkey: rq.body.pubkey,
            });
            if (obj == null) {
                log.w(`Obj null`);
                rs.sendStatus(500);
                return;
            } else user = obj;
        }
        if (!(await user.addNonce(rq.body.message.nonce))) {
            log.w(
                `Client '${rq.body.client_id}' has already used nonce. Replay attack?`,
            );
            authFailed("Authentication request failed.");
            return;
        }
        user.addAssociatedIp(getSrcIpDefault(rq));

        const token = await user.getToken();
        rs.json({ token: token });
    },
);

const checkRateLimit = new APIUtils.RateLimiter(10, 3);

route.router.get('/checkExpired', checkRateLimit.middle(), async (rq, rs) => {

    const token = rq.header('GalvanicAuth');
    if (!token) {
        rs.json(true);
        return;
    }

    try {
        const decodedToken = await decode<UserTokenFormat>(token, config.auth.secret, { algorithm: "HS512", leeway: 31536000 }); // 1 year leeway
        rs.json(decodedToken.exp < Math.round(Date.now() / 1000));
    } catch {
        rs.json(true);
    }

});