Implement Webauthn 🎉 (#5088)

* Implement Webauthn :tada:

* 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

4 files changed, 324 insertions, 0 deletions

diff --git a/src/server/api/endpoints/i/2fa/getkeys.ts b/src/server/api/endpoints/i/2fa/getkeys.ts
new file mode 100644
index 0000000000..bb1585d795
--- /dev/null
+++ b/src/server/api/endpoints/i/2fa/getkeys.ts
@@ -0,0 +1,67 @@
+import $ from 'cafy';
+import * as bcrypt from 'bcryptjs';
+import * as crypto from 'crypto';
+import define from '../../../define';
+import { UserProfiles, UserSecurityKeys, AttestationChallenges } from '../../../../../models';
+import { ensure } from '../../../../../prelude/ensure';
+import { promisify } from 'util';
+import { hash } from '../../../2fa';
+import { genId } from '../../../../../misc/gen-id';
+
+export const meta = {
+	requireCredential: true,
+
+	secure: true,
+
+	params: {
+		password: {
+			validator: $.str
+		}
+	}
+};
+
+const randomBytes = promisify(crypto.randomBytes);
+
+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');
+	}
+
+	const keys = await UserSecurityKeys.find({
+		userId: user.id
+	});
+
+	if (keys.length === 0) {
+		throw new Error('no keys found');
+	}
+
+	// 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: false
+	});
+
+	return {
+		challenge,
+		challengeId,
+		securityKeys: keys.map(key => ({
+			id: key.id
+		}))
+	};
+});
diff --git a/src/server/api/endpoints/i/2fa/key-done.ts b/src/server/api/endpoints/i/2fa/key-done.ts
new file mode 100644
index 0000000000..074ab22bf0
--- /dev/null
+++ b/src/server/api/endpoints/i/2fa/key-done.ts
@@ -0,0 +1,151 @@
+import $ from 'cafy';
+import * as bcrypt from 'bcryptjs';
+import { promisify } from 'util';
+import * as cbor from 'cbor';
+import define from '../../../define';
+import {
+	UserProfiles,
+	UserSecurityKeys,
+	AttestationChallenges,
+	Users
+} from '../../../../../models';
+import { ensure } from '../../../../../prelude/ensure';
+import config from '../../../../../config';
+import { procedures, hash } from '../../../2fa';
+import { publishMainStream } from '../../../../../services/stream';
+
+const cborDecodeFirst = promisify(cbor.decodeFirst);
+
+export const meta = {
+	requireCredential: true,
+
+	secure: true,
+
+	params: {
+		clientDataJSON: {
+			validator: $.str
+		},
+		attestationObject: {
+			validator: $.str
+		},
+		password: {
+			validator: $.str
+		},
+		challengeId: {
+			validator: $.str
+		},
+		name: {
+			validator: $.str
+		}
+	}
+};
+
+const rpIdHashReal = hash(Buffer.from(config.hostname, 'utf-8'));
+
+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');
+	}
+
+	const clientData = JSON.parse(ps.clientDataJSON);
+
+	if (clientData.type != 'webauthn.create') {
+		throw new Error('not a creation attestation');
+	}
+	if (clientData.origin != config.scheme + '://' + config.host) {
+		throw new Error('origin mismatch');
+	}
+
+	const clientDataJSONHash = hash(Buffer.from(ps.clientDataJSON, 'utf-8'));
+
+	const attestation = await cborDecodeFirst(ps.attestationObject);
+
+	const rpIdHash = attestation.authData.slice(0, 32);
+	if (!rpIdHashReal.equals(rpIdHash)) {
+		throw new Error('rpIdHash mismatch');
+	}
+
+	const flags = attestation.authData[32];
+
+	// tslint:disable-next-line:no-bitwise
+	if (!(flags & 1)) {
+		throw new Error('user not present');
+	}
+
+	const authData = Buffer.from(attestation.authData);
+	const credentialIdLength = authData.readUInt16BE(53);
+	const credentialId = authData.slice(55, 55 + credentialIdLength);
+	const publicKeyData = authData.slice(55 + credentialIdLength);
+	const publicKey: Map<number, any> = await cborDecodeFirst(publicKeyData);
+	if (publicKey.get(3) != -7) {
+		throw new Error('alg mismatch');
+	}
+
+	if (!procedures[attestation.fmt]) {
+		throw new Error('unsupported fmt');
+	}
+
+	const verificationData = procedures[attestation.fmt].verify({
+		attStmt: attestation.attStmt,
+		authenticatorData: authData,
+		clientDataHash: clientDataJSONHash,
+		credentialId,
+		publicKey,
+		rpIdHash
+	});
+	if (!verificationData.valid) throw new Error('signature invalid');
+
+	const attestationChallenge = await AttestationChallenges.findOne({
+		userId: user.id,
+		id: ps.challengeId,
+		registrationChallenge: true,
+		challenge: hash(clientData.challenge).toString('hex')
+	});
+
+	if (!attestationChallenge) {
+		throw new Error('non-existent challenge');
+	}
+
+	await AttestationChallenges.delete({
+		userId: user.id,
+		id: ps.challengeId
+	});
+
+	// Expired challenge (> 5min old)
+	if (
+		new Date().getTime() - attestationChallenge.createdAt.getTime() >=
+		5 * 60 * 1000
+	) {
+		throw new Error('expired challenge');
+	}
+
+	const credentialIdString = credentialId.toString('hex');
+
+	await UserSecurityKeys.save({
+		userId: user.id,
+		id: credentialIdString,
+		lastUsed: new Date(),
+		name: ps.name,
+		publicKey: verificationData.publicKey.toString('hex')
+	});
+
+	// Publish meUpdated event
+	publishMainStream(user.id, 'meUpdated', await Users.pack(user.id, user, {
+		detail: true,
+		includeSecrets: true
+	}));
+
+	return {
+		id: credentialIdString,
+		name: ps.name
+	};
+});
diff --git a/src/server/api/endpoints/i/2fa/register-key.ts b/src/server/api/endpoints/i/2fa/register-key.ts
new file mode 100644
index 0000000000..1c2cc32e37
--- /dev/null
+++ b/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
+	};
+});
diff --git a/src/server/api/endpoints/i/2fa/remove-key.ts b/src/server/api/endpoints/i/2fa/remove-key.ts
new file mode 100644
index 0000000000..cb28c8fbfb
--- /dev/null
+++ b/src/server/api/endpoints/i/2fa/remove-key.ts
@@ -0,0 +1,46 @@
+import $ from 'cafy';
+import * as bcrypt from 'bcryptjs';
+import define from '../../../define';
+import { UserProfiles, UserSecurityKeys, Users } from '../../../../../models';
+import { ensure } from '../../../../../prelude/ensure';
+import { publishMainStream } from '../../../../../services/stream';
+
+export const meta = {
+	requireCredential: true,
+
+	secure: true,
+
+	params: {
+		password: {
+			validator: $.str
+		},
+		credentialId: {
+			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');
+	}
+
+	// Make sure we only delete the user's own creds
+	await UserSecurityKeys.delete({
+		userId: user.id,
+		id: ps.credentialId
+	});
+
+	// Publish meUpdated event
+	publishMainStream(user.id, 'meUpdated', await Users.pack(user.id, user, {
+		detail: true,
+		includeSecrets: true
+	}));
+
+	return {};
+});