Implement Webauthn 🎉 (#5088)

* Implement Webauthn 🎉

* Share hexifyAB

* Move hr inside template and add AttestationChallenges janitor daemon

* Apply suggestions from code review

Co-Authored-By: Acid Chicken (硫酸鶏) <root@acid-chicken.com>

* Add newline at the end of file

* Fix stray newline in promise chain

* Ignore var in try{}catch(){} block

Co-Authored-By: Acid Chicken (硫酸鶏) <root@acid-chicken.com>

* Add missing comma

* Add missing semicolon

* Support more attestation formats

* add support for more key types and linter pass

* Refactor

* Refactor

* credentialId --> id

* Fix

* Improve readability

* Add indexes

* fixes for credentialId->id

* Avoid changing store state

* Fix syntax error and code style

* Remove unused import

* Refactor of getkey API

* Create 1561706992953-webauthn.ts

* Update ja-JP.yml

* Add type annotations

* Fix code style

* Specify depedency version

* Fix code style

* Fix janitor daemon and login requesting 2FA regardless of status

src/server/api/endpoints/i/2fa/register-key.ts

@@ -0,0 +1,60 @@
+import $ from 'cafy';
+import * as bcrypt from 'bcryptjs';
+import define from '../../../define';
+import { UserProfiles, AttestationChallenges } from '../../../../../models';
+import { ensure } from '../../../../../prelude/ensure';
+import { promisify } from 'util';
+import * as crypto from 'crypto';
+import { genId } from '../../../../../misc/gen-id';
+import { hash } from '../../../2fa';
+
+const randomBytes = promisify(crypto.randomBytes);
+
+export const meta = {
+	requireCredential: true,
+
+	secure: true,
+
+	params: {
+		password: {
+			validator: $.str
+		}
+	}
+};
+
+export default define(meta, async (ps, user) => {
+	const profile = await UserProfiles.findOne(user.id).then(ensure);
+
+	// Compare password
+	const same = await bcrypt.compare(ps.password, profile.password!);
+
+	if (!same) {
+		throw new Error('incorrect password');
+	}
+
+	if (!profile.twoFactorEnabled) {
+		throw new Error('2fa not enabled');
+	}
+
+	// 32 byte challenge
+	const entropy = await randomBytes(32);
+	const challenge = entropy.toString('base64')
+		.replace(/=/g, '')
+		.replace(/\+/g, '-')
+		.replace(/\//g, '_');
+
+	const challengeId = genId();
+
+	await AttestationChallenges.save({
+		userId: user.id,
+		id: challengeId,
+		challenge: hash(Buffer.from(challenge, 'utf-8')).toString('hex'),
+		createdAt: new Date(),
+		registrationChallenge: true
+	});
+
+	return {
+		challengeId,
+		challenge
+	};
+});