Implement WebAuthn (#967)

* implement webauthn

* code review

---------

Co-authored-by: Madeline <46743919+MaddyUnderStars@users.noreply.github.com>

src/api/Server.ts

@@ -19,7 +19,13 @@
 import "missing-native-js-functions";
 import { Server, ServerOptions } from "lambert-server";
 import { Authentication, CORS } from "./middlewares/";
-import { Config, initDatabase, initEvent, Sentry } from "@fosscord/util";
+import {
+	Config,
+	initDatabase,
+	initEvent,
+	Sentry,
+	WebAuthn,
+} from "@fosscord/util";
 import { ErrorHandler } from "./middlewares/ErrorHandler";
 import { BodyParser } from "./middlewares/BodyParser";
 import { Router, Request, Response } from "express";
@@ -58,6 +64,7 @@ export class FosscordServer extends Server {
 		await initEvent();
 		await initInstance();
 		await Sentry.init(this.app);
+		WebAuthn.init();
 
 		const logRequests = process.env["LOG_REQUESTS"] != undefined;
 		if (logRequests) {

src/api/middlewares/Authentication.ts

@@ -27,6 +27,7 @@ export const NO_AUTHORIZATION_ROUTES = [
 	"/auth/register",
 	"/auth/location-metadata",
 	"/auth/mfa/totp",
+	"/auth/mfa/webauthn",
 	// Routes with a seperate auth system
 	"/webhooks/",
 	// Public information endpoints

src/api/routes/auth/login.ts

@@ -16,18 +16,20 @@
 	along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-import { Request, Response, Router } from "express";
-import { route, getIpAdress, verifyCaptcha } from "@fosscord/api";
-import bcrypt from "bcrypt";
+import { getIpAdress, route, verifyCaptcha } from "@fosscord/api";
 import {
-	Config,
-	User,
-	generateToken,
 	adjustEmail,
+	Config,
 	FieldErrors,
+	generateToken,
+	generateWebAuthnTicket,
 	LoginSchema,
+	User,
+	WebAuthn,
 } from "@fosscord/util";
+import bcrypt from "bcrypt";
 import crypto from "crypto";
+import { Request, Response, Router } from "express";
 
 const router: Router = Router();
 export default router;
@@ -73,7 +75,10 @@ router.post(
 				"settings",
 				"totp_secret",
 				"mfa_enabled",
+				"webauthn_enabled",
+				"security_keys",
 			],
+			relations: ["security_keys"],
 		}).catch(() => {
 			throw FieldErrors({
 				login: {
@@ -116,7 +121,7 @@ router.post(
 			});
 		}
 
-		if (user.mfa_enabled) {
+		if (user.mfa_enabled && !user.webauthn_enabled) {
 			// TODO: This is not a discord.com ticket. I'm not sure what it is but I'm lazy
 			const ticket = crypto.randomBytes(40).toString("hex");
 
@@ -130,6 +135,40 @@ router.post(
 			});
 		}
 
+		if (user.mfa_enabled && user.webauthn_enabled) {
+			if (!WebAuthn.fido2) {
+				// TODO: I did this for typescript and I can't use !
+				throw new Error("WebAuthn not enabled");
+			}
+
+			const options = await WebAuthn.fido2.assertionOptions();
+			const challenge = JSON.stringify({
+				publicKey: {
+					...options,
+					challenge: Buffer.from(options.challenge).toString(
+						"base64",
+					),
+					allowCredentials: user.security_keys.map((x) => ({
+						id: x.key_id,
+						type: "public-key",
+					})),
+					transports: ["usb", "ble", "nfc"],
+					timeout: 60000,
+				},
+			});
+
+			const ticket = await generateWebAuthnTicket(challenge);
+			await User.update({ id: user.id }, { totp_last_ticket: ticket });
+
+			return res.json({
+				ticket: ticket,
+				mfa: true,
+				sms: false, // TODO
+				token: null,
+				webauthn: challenge,
+			});
+		}
+
 		const token = await generateToken(user.id);
 
 		// Notice this will have a different token structure, than discord
@@ -147,6 +186,9 @@ router.post(
  * MFA required:
  * @returns {"token": null, "mfa": true, "sms": true, "ticket": "SOME TICKET JWT TOKEN"}
 
+ * WebAuthn MFA required:
+ * @returns {"token": null, "mfa": true, "webauthn": true, "sms": true, "ticket": "SOME TICKET JWT TOKEN"}
+
  * Captcha required:
  * @returns {"captcha_key": ["captcha-required"], "captcha_sitekey": null, "captcha_service": "recaptcha"}
 

src/api/routes/auth/mfa/webauthn.ts

@@ -0,0 +1,112 @@
+/*
+	Fosscord: A FOSS re-implementation and extension of the Discord.com backend.
+	Copyright (C) 2023 Fosscord and Fosscord Contributors
+	
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published
+	by the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+	
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+	
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+import { route } from "@fosscord/api";
+import {
+	generateToken,
+	SecurityKey,
+	User,
+	verifyWebAuthnToken,
+	WebAuthn,
+	WebAuthnTotpSchema,
+} from "@fosscord/util";
+import { Request, Response, Router } from "express";
+import { ExpectedAssertionResult } from "fido2-lib";
+import { HTTPError } from "lambert-server";
+const router = Router();
+
+function toArrayBuffer(buf: Buffer) {
+	const ab = new ArrayBuffer(buf.length);
+	const view = new Uint8Array(ab);
+	for (let i = 0; i < buf.length; ++i) {
+		view[i] = buf[i];
+	}
+	return ab;
+}
+
+router.post(
+	"/",
+	route({ body: "WebAuthnTotpSchema" }),
+	async (req: Request, res: Response) => {
+		if (!WebAuthn.fido2) {
+			// TODO: I did this for typescript and I can't use !
+			throw new Error("WebAuthn not enabled");
+		}
+
+		const { code, ticket } = req.body as WebAuthnTotpSchema;
+
+		const user = await User.findOneOrFail({
+			where: {
+				totp_last_ticket: ticket,
+			},
+			select: ["id", "settings"],
+		});
+
+		const ret = await verifyWebAuthnToken(ticket);
+		if (!ret)
+			throw new HTTPError(req.t("auth:login.INVALID_TOTP_CODE"), 60008);
+
+		await User.update({ id: user.id }, { totp_last_ticket: "" });
+
+		const clientAttestationResponse = JSON.parse(code);
+		const securityKey = await SecurityKey.findOneOrFail({
+			where: {
+				user_id: req.user_id,
+				key_id: clientAttestationResponse.rawId,
+			},
+		});
+
+		if (!clientAttestationResponse.rawId)
+			throw new HTTPError("Missing rawId", 400);
+
+		clientAttestationResponse.rawId = toArrayBuffer(
+			Buffer.from(clientAttestationResponse.rawId, "base64"),
+		);
+
+		const assertionExpectations: ExpectedAssertionResult = JSON.parse(
+			Buffer.from(
+				clientAttestationResponse.response.clientDataJSON,
+				"base64",
+			).toString(),
+		);
+
+		const authnResult = await WebAuthn.fido2.assertionResult(
+			clientAttestationResponse,
+			{
+				...assertionExpectations,
+				factor: "second",
+				publicKey: securityKey.public_key,
+				prevCounter: securityKey.counter,
+				userHandle: securityKey.key_id,
+			},
+		);
+
+		const counter = authnResult.authnrData.get("counter");
+
+		securityKey.counter = counter;
+
+		await securityKey.save();
+
+		return res.json({
+			token: await generateToken(user.id),
+			user_settings: user.settings,
+		});
+	},
+);
+
+export default router;

src/api/routes/users/@me/mfa/webauthn/credentials/#key_id/index.ts

@@ -0,0 +1,35 @@
+/*
+	Fosscord: A FOSS re-implementation and extension of the Discord.com backend.
+	Copyright (C) 2023 Fosscord and Fosscord Contributors
+	
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published
+	by the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+	
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+	
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+import { route } from "@fosscord/api";
+import { SecurityKey } from "@fosscord/util";
+import { Request, Response, Router } from "express";
+const router = Router();
+
+router.delete("/", route({}), async (req: Request, res: Response) => {
+	const { key_id } = req.params;
+
+	await SecurityKey.delete({
+		id: key_id,
+		user_id: req.user_id,
+	});
+
+	res.sendStatus(204);
+});
+
+export default router;

src/api/routes/users/@me/mfa/webauthn/credentials/index.ts

@@ -0,0 +1,196 @@
+/*
+	Fosscord: A FOSS re-implementation and extension of the Discord.com backend.
+	Copyright (C) 2023 Fosscord and Fosscord Contributors
+	
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published
+	by the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+	
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+	
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+import { route } from "@fosscord/api";
+import {
+	CreateWebAuthnCredentialSchema,
+	DiscordApiErrors,
+	FieldErrors,
+	GenerateWebAuthnCredentialsSchema,
+	generateWebAuthnTicket,
+	SecurityKey,
+	User,
+	verifyWebAuthnToken,
+	WebAuthn,
+	WebAuthnPostSchema,
+} from "@fosscord/util";
+import bcrypt from "bcrypt";
+import { Request, Response, Router } from "express";
+import { ExpectedAttestationResult } from "fido2-lib";
+import { HTTPError } from "lambert-server";
+const router = Router();
+
+const isGenerateSchema = (
+	body: WebAuthnPostSchema,
+): body is GenerateWebAuthnCredentialsSchema => {
+	return "password" in body;
+};
+
+const isCreateSchema = (
+	body: WebAuthnPostSchema,
+): body is CreateWebAuthnCredentialSchema => {
+	return "credential" in body;
+};
+
+function toArrayBuffer(buf: Buffer) {
+	const ab = new ArrayBuffer(buf.length);
+	const view = new Uint8Array(ab);
+	for (let i = 0; i < buf.length; ++i) {
+		view[i] = buf[i];
+	}
+	return ab;
+}
+
+router.get("/", route({}), async (req: Request, res: Response) => {
+	const securityKeys = await SecurityKey.find({
+		where: {
+			user_id: req.user_id,
+		},
+	});
+
+	return res.json(
+		securityKeys.map((key) => ({
+			id: key.id,
+			name: key.name,
+		})),
+	);
+});
+
+router.post(
+	"/",
+	route({ body: "WebAuthnPostSchema" }),
+	async (req: Request, res: Response) => {
+		if (!WebAuthn.fido2) {
+			// TODO: I did this for typescript and I can't use !
+			throw new Error("WebAuthn not enabled");
+		}
+
+		const user = await User.findOneOrFail({
+			where: {
+				id: req.user_id,
+			},
+			select: [
+				"data",
+				"id",
+				"disabled",
+				"deleted",
+				"settings",
+				"totp_secret",
+				"mfa_enabled",
+				"username",
+			],
+		});
+
+		if (isGenerateSchema(req.body)) {
+			const { password } = req.body;
+			const same_password = await bcrypt.compare(
+				password,
+				user.data.hash || "",
+			);
+			if (!same_password) {
+				throw FieldErrors({
+					password: {
+						message: req.t("auth:login.INVALID_PASSWORD"),
+						code: "INVALID_PASSWORD",
+					},
+				});
+			}
+
+			const registrationOptions =
+				await WebAuthn.fido2.attestationOptions();
+			const challenge = JSON.stringify({
+				publicKey: {
+					...registrationOptions,
+					challenge: Buffer.from(
+						registrationOptions.challenge,
+					).toString("base64"),
+					user: {
+						id: user.id,
+						name: user.username,
+						displayName: user.username,
+					},
+				},
+			});
+
+			const ticket = await generateWebAuthnTicket(challenge);
+
+			return res.json({
+				ticket: ticket,
+				challenge,
+			});
+		} else if (isCreateSchema(req.body)) {
+			const { credential, name, ticket } = req.body;
+
+			const verified = await verifyWebAuthnToken(ticket);
+			if (!verified) throw new HTTPError("Invalid ticket", 400);
+
+			const clientAttestationResponse = JSON.parse(credential);
+
+			if (!clientAttestationResponse.rawId)
+				throw new HTTPError("Missing rawId", 400);
+
+			const rawIdBuffer = Buffer.from(
+				clientAttestationResponse.rawId,
+				"base64",
+			);
+			clientAttestationResponse.rawId = toArrayBuffer(rawIdBuffer);
+
+			const attestationExpectations: ExpectedAttestationResult =
+				JSON.parse(
+					Buffer.from(
+						clientAttestationResponse.response.clientDataJSON,
+						"base64",
+					).toString(),
+				);
+
+			const regResult = await WebAuthn.fido2.attestationResult(
+				clientAttestationResponse,
+				{
+					...attestationExpectations,
+					factor: "second",
+				},
+			);
+
+			const authnrData = regResult.authnrData;
+			const keyId = Buffer.from(authnrData.get("credId")).toString(
+				"base64",
+			);
+			const counter = authnrData.get("counter");
+			const publicKey = authnrData.get("credentialPublicKeyPem");
+
+			const securityKey = SecurityKey.create({
+				name,
+				counter,
+				public_key: publicKey,
+				user_id: req.user_id,
+				key_id: keyId,
+			});
+
+			await securityKey.save();
+
+			return res.json({
+				name,
+				id: securityKey.id,
+			});
+		} else {
+			throw DiscordApiErrors.INVALID_AUTHENTICATION_TOKEN;
+		}
+	},
+);
+
+export default router;