fix: Use `@simplewebauthn` for frontend logic

This simplifies the code a lot and fixes errors with the exisiting custom code,
where slightly different base64 values were emitted which are not valid according to the standard.

ref: https://github.com/web-auth/webauthn-framework/issues/510

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

5 files changed, 124 insertions, 113 deletions

diff --git a/apps/settings/src/components/WebAuthn/AddDevice.vue b/apps/settings/src/components/WebAuthn/AddDevice.vue
index b9e9d087a0b..72077003cdd 100644
--- a/apps/settings/src/components/WebAuthn/AddDevice.vue
+++ b/apps/settings/src/components/WebAuthn/AddDevice.vue
@@ -24,11 +24,11 @@
 		{{ t('settings', 'Passwordless authentication requires a secure connection.') }}
 	</div>
 	<div v-else>
-		<div v-if="step === RegistrationSteps.READY">
-			<NcButton @click="start" type="primary">
-				{{ t('settings', 'Add WebAuthn device') }}
-			</NcButton>
-		</div>
+		<NcButton v-if="step === RegistrationSteps.READY"
+			type="primary"
+			@click="start">
+			{{ t('settings', 'Add WebAuthn device') }}
+		</NcButton>
 
 		<div v-else-if="step === RegistrationSteps.REGISTRATION"
 			class="new-webauthn-device">
@@ -39,13 +39,14 @@
 		<div v-else-if="step === RegistrationSteps.NAMING"
 			class="new-webauthn-device">
 			<span class="icon-loading-small webauthn-loading" />
-			<input v-model="name"
-				type="text"
-				:placeholder="t('settings', 'Name your device')"
-				@:keyup.enter="submit">
-			<NcButton @click="submit" type="primary">
-				{{ t('settings', 'Add') }}
-			</NcButton>
+			<NcTextField ref="nameInput"
+				class="new-webauthn-device__name"
+				:label="t('settings', 'Device name')"
+				:value.sync="name"
+				show-trailing-button
+				:trailing-button-label="t('settings', 'Add')"
+				trailing-button-icon="arrowRight"
+				@trailing-button-click="submit" />
 		</div>
 
 		<div v-else-if="step === RegistrationSteps.PERSIST"
@@ -61,15 +62,16 @@
 </template>
 
 <script>
+import { showError } from '@nextcloud/dialogs'
 import { confirmPassword } from '@nextcloud/password-confirmation'
 import NcButton from '@nextcloud/vue/dist/Components/NcButton.js'
-import '@nextcloud/password-confirmation/dist/style.css'
+import NcTextField from '@nextcloud/vue/dist/Components/NcTextField.js'
 
 import logger from '../../logger.ts'
 import {
 	startRegistration,
 	finishRegistration,
-} from '../../service/WebAuthnRegistrationSerice.js'
+} from '../../service/WebAuthnRegistrationSerice.ts'
 
 const logAndPass = (text) => (data) => {
 	logger.debug(text)
@@ -88,6 +90,7 @@ export default {
 
 	components: {
 		NcButton,
+		NcTextField,
 	},
 
 	props: {
@@ -101,83 +104,55 @@ export default {
 			default: false,
 		},
 	},
+
+	setup() {
+		// non reactive props
+		return {
+			RegistrationSteps,
+		}
+	},
+
 	data() {
 		return {
 			name: '',
 			credential: {},
-			RegistrationSteps,
 			step: RegistrationSteps.READY,
 		}
 	},
-	methods: {
-		arrayToBase64String(a) {
-			return btoa(String.fromCharCode(...a))
+
+	watch: {
+		/**
+		 * Auto focus the name input when naming a device
+		 */
+		step() {
+			if (this.step === RegistrationSteps.NAMING) {
+				this.$nextTick(() => this.$refs.nameInput?.focus())
+			}
 		},
-		start() {
+	},
+
+	methods: {
+		/**
+		 * Start the registration process by loading the authenticator parameters
+		 * The next step is the naming of the device
+		 */
+		async start() {
 			this.step = RegistrationSteps.REGISTRATION
 			console.debug('Starting WebAuthn registration')
 
-			return confirmPassword()
-				.then(this.getRegistrationData)
-				.then(this.register.bind(this))
-				.then(() => { this.step = RegistrationSteps.NAMING })
-				.catch(err => {
-					console.error(err.name, err.message)
-					this.step = RegistrationSteps.READY
-				})
-		},
-
-		getRegistrationData() {
-			console.debug('Fetching webauthn registration data')
-
-			const base64urlDecode = function(input) {
-				// Replace non-url compatible chars with base64 standard chars
-				input = input
-					.replace(/-/g, '+')
-					.replace(/_/g, '/')
-
-				// Pad out with standard base64 required padding characters
-				const pad = input.length % 4
-				if (pad) {
-					if (pad === 1) {
-						throw new Error('InvalidLengthError: Input base64url string is the wrong length to determine padding')
-					}
-					input += new Array(5 - pad).join('=')
-				}
-
-				return window.atob(input)
+			try {
+				await confirmPassword()
+				this.credential = await startRegistration()
+				this.step = RegistrationSteps.NAMING
+			} catch (err) {
+				showError(err)
+				this.step = RegistrationSteps.READY
 			}
-
-			return startRegistration()
-				.then(publicKey => {
-					console.debug(publicKey)
-					publicKey.challenge = Uint8Array.from(base64urlDecode(publicKey.challenge), c => c.charCodeAt(0))
-					publicKey.user.id = Uint8Array.from(publicKey.user.id, c => c.charCodeAt(0))
-					return publicKey
-				})
-				.catch(err => {
-					console.error('Error getting webauthn registration data from server', err)
-					throw new Error(t('settings', 'Server error while trying to add WebAuthn device'))
-				})
-		},
-
-		register(publicKey) {
-			console.debug('starting webauthn registration')
-
-			return navigator.credentials.create({ publicKey })
-				.then(data => {
-					this.credential = {
-						id: data.id,
-						type: data.type,
-						rawId: this.arrayToBase64String(new Uint8Array(data.rawId)),
-						response: {
-							clientDataJSON: this.arrayToBase64String(new Uint8Array(data.response.clientDataJSON)),
-							attestationObject: this.arrayToBase64String(new Uint8Array(data.response.attestationObject)),
-						},
-					}
-				})
 		},
 
+		/**
+		 * Save the new device with the given name on the server
+		 */
 		submit() {
 			this.step = RegistrationSteps.PERSIST
 
@@ -187,12 +162,12 @@ export default {
 				.then(logAndPass('registration data saved'))
 				.then(() => this.reset())
 				.then(logAndPass('app reset'))
-				.catch(console.error.bind(this))
+				.catch(console.error)
 		},
 
 		async saveRegistrationData() {
 			try {
-				const device = await finishRegistration(this.name, JSON.stringify(this.credential))
+				const device = await finishRegistration(this.name, this.credential)
 
 				logger.info('new device added', { device })
 
@@ -212,15 +187,21 @@ export default {
 }
 </script>
 
-<style scoped>
-	.webauthn-loading {
-		display: inline-block;
-		vertical-align: sub;
-		margin-left: 2px;
-		margin-right: 2px;
-	}
+<style scoped lang="scss">
+.webauthn-loading {
+	display: inline-block;
+	vertical-align: sub;
+	margin-left: 2px;
+	margin-right: 2px;
+}
+
+.new-webauthn-device {
+	display: flex;
+	gap: 22px;
+	align-items: center;
 
-	.new-webauthn-device {
-		line-height: 300%;
+	&__name {
+		max-width: min(100vw, 400px);
 	}
+}
 </style>
diff --git a/apps/settings/src/components/WebAuthn/Device.vue b/apps/settings/src/components/WebAuthn/Device.vue
index 1de2661b8dc..319c99c3184 100644
--- a/apps/settings/src/components/WebAuthn/Device.vue
+++ b/apps/settings/src/components/WebAuthn/Device.vue
@@ -20,7 +20,7 @@
   -->
 
 <template>
-	<div class="webauthn-device">
+	<li class="webauthn-device">
 		<span class="icon-webauthn-device" />
 		{{ name || t('settings', 'Unnamed device') }}
 		<NcActions :force-menu="true">
@@ -28,7 +28,7 @@
 				{{ t('settings', 'Delete') }}
 			</NcActionButton>
 		</NcActions>
-	</div>
+	</li>
 </template>
 
 <script>
diff --git a/apps/settings/src/components/WebAuthn/Section.vue b/apps/settings/src/components/WebAuthn/Section.vue
index 2f5c840bdcc..7e9c75b9264 100644
--- a/apps/settings/src/components/WebAuthn/Section.vue
+++ b/apps/settings/src/components/WebAuthn/Section.vue
@@ -28,19 +28,22 @@
 		<NcNoteCard v-if="devices.length === 0" type="info">
 			{{ t('settings', 'No devices configured.') }}
 		</NcNoteCard>
-		<h3 v-else>
+
+		<h3 v-else id="security-webauthn__active-devices">
 			{{ t('settings', 'The following devices are configured for your account:') }}
 		</h3>
-		<Device v-for="device in sortedDevices"
-			:key="device.id"
-			:name="device.name"
-			@delete="deleteDevice(device.id)" />
+		<ul aria-labelledby="security-webauthn__active-devices" class="security-webauthn__device-list">
+			<Device v-for="device in sortedDevices"
+				:key="device.id"
+				:name="device.name"
+				@delete="deleteDevice(device.id)" />
+		</ul>
 
-		<NcNoteCard v-if="!hasPublicKeyCredential" type="warning">
+		<NcNoteCard v-if="!supportsWebauthn" type="warning">
 			{{ t('settings', 'Your browser does not support WebAuthn.') }}
 		</NcNoteCard>
 
-		<AddDevice v-if="hasPublicKeyCredential"
+		<AddDevice v-if="supportsWebauthn"
 			:is-https="isHttps"
 			:is-localhost="isLocalhost"
 			@added="deviceAdded" />
@@ -48,6 +51,7 @@
 </template>
 
 <script>
+import { browserSupportsWebAuthn } from '@simplewebauthn/browser'
 import { confirmPassword } from '@nextcloud/password-confirmation'
 import NcNoteCard from '@nextcloud/vue/dist/Components/NcNoteCard.js'
 import '@nextcloud/password-confirmation/dist/style.css'
@@ -79,11 +83,15 @@ export default {
 			type: Boolean,
 			default: false,
 		},
-		hasPublicKeyCredential: {
-			type: Boolean,
-			default: false,
-		},
 	},
+
+	setup() {
+		// Non reactive properties
+		return {
+			supportsWebauthn: browserSupportsWebAuthn(),
+		}
+	},
+
 	data() {
 		return {
 			devices: this.initialDevices,
@@ -115,5 +123,7 @@ export default {
 </script>
 
 <style scoped>
-
+.security-webauthn__device-list {
+	margin-block: 12px 18px;
+}
 </style>
diff --git a/apps/settings/src/main-personal-webauth.js b/apps/settings/src/main-personal-webauth.js
index dc11ecdbba2..edbdde6ea27 100644
--- a/apps/settings/src/main-personal-webauth.js
+++ b/apps/settings/src/main-personal-webauth.js
@@ -37,6 +37,5 @@ new View({
 		initialDevices: devices,
 		isHttps: window.location.protocol === 'https:',
 		isLocalhost: window.location.hostname === 'localhost',
-		hasPublicKeyCredential: typeof (window.PublicKeyCredential) !== 'undefined',
 	},
 }).$mount('#security-webauthn')
diff --git a/apps/settings/src/service/WebAuthnRegistrationSerice.js b/apps/settings/src/service/WebAuthnRegistrationSerice.ts
index 185dbd8cf28..f95395e865a 100644
--- a/apps/settings/src/service/WebAuthnRegistrationSerice.js
+++ b/apps/settings/src/service/WebAuthnRegistrationSerice.ts
@@ -20,34 +20,55 @@
  *
  */
 
-import axios from '@nextcloud/axios'
+import type { RegistrationResponseJSON } from '@simplewebauthn/types'
+
+import { translate as t } from '@nextcloud/l10n'
 import { generateUrl } from '@nextcloud/router'
+import { startRegistration as registerWebAuthn } from '@simplewebauthn/browser'
+
+import Axios from 'axios'
+import axios from '@nextcloud/axios'
+import logger from '../logger'
 
 /**
- *
+ * Start registering a new device
+ * @return The device attributes
  */
 export async function startRegistration() {
 	const url = generateUrl('/settings/api/personal/webauthn/registration')
 
-	const resp = await axios.get(url)
-	return resp.data
+	try {
+		logger.debug('Fetching webauthn registration data')
+		const { data } = await axios.get(url)
+		logger.debug('Start webauthn registration')
+		const attrs = await registerWebAuthn(data)
+		return attrs
+	} catch (e) {
+		logger.error(e as Error)
+		if (Axios.isAxiosError(e)) {
+			throw new Error(t('settings', 'Could not register device: Network error'))
+		} else if ((e as Error).name === 'InvalidStateError') {
+			throw new Error(t('settings', 'Could not register device: Probably already registered'))
+		}
+		throw new Error(t('settings', 'Could not register device'))
+	}
 }
 
 /**
- * @param {any} name -
- * @param {any} data -
+ * @param name Name of the device
+ * @param data Device attributes
  */
-export async function finishRegistration(name, data) {
+export async function finishRegistration(name: string, data: RegistrationResponseJSON) {
 	const url = generateUrl('/settings/api/personal/webauthn/registration')
 
-	const resp = await axios.post(url, { name, data })
+	const resp = await axios.post(url, { name, data: JSON.stringify(data) })
 	return resp.data
 }
 
 /**
- * @param {any} id -
+ * @param id Remove registered device with that id
  */
-export async function removeRegistration(id) {
+export async function removeRegistration(id: string | number) {
 	const url = generateUrl(`/settings/api/personal/webauthn/registration/${id}`)
 
 	await axios.delete(url)