From 3a15142940ef9391868442e1997c3d9d5eec33be Mon Sep 17 00:00:00 2001
From: Aman Harwara <amanharwara@protonmail.com>
Date: Thu, 15 Sep 2022 23:41:03 +0530
Subject: [PATCH] fix: biometrics input on mobile webview challenge modal
 (#1572)

---
 packages/mobile/src/Lib/Interface.ts          | 47 +++++++++++++++++
 .../Domain/Device/MobileDeviceInterface.ts    |  1 +
 .../ChallengeModal/ChallengeModal.tsx         | 20 ++++++--
 .../ChallengeModal/ChallengePrompt.tsx        | 51 +++++++++++++++++--
 4 files changed, 111 insertions(+), 8 deletions(-)

diff --git a/packages/mobile/src/Lib/Interface.ts b/packages/mobile/src/Lib/Interface.ts
index f3a02ac41..4e6931064 100644
--- a/packages/mobile/src/Lib/Interface.ts
+++ b/packages/mobile/src/Lib/Interface.ts
@@ -288,6 +288,53 @@ export class MobileDeviceInterface implements DeviceInterface {
     }
   }
 
+  authenticateWithBiometrics() {
+    return new Promise<boolean>((resolve) => {
+      if (Platform.OS === 'android') {
+        FingerprintScanner.authenticate({
+          // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+          // @ts-ignore ts type does not exist for deviceCredentialAllowed
+          deviceCredentialAllowed: true,
+          description: 'Biometrics are required to access your notes.',
+        })
+          .then(() => {
+            FingerprintScanner.release()
+            resolve(true)
+          })
+          .catch((error) => {
+            FingerprintScanner.release()
+            if (error.name === 'DeviceLocked') {
+              Alert.alert('Unsuccessful', 'Authentication failed. Wait 30 seconds to try again.')
+            } else {
+              Alert.alert('Unsuccessful', 'Authentication failed. Tap to try again.')
+            }
+            resolve(false)
+          })
+      } else {
+        // iOS
+        FingerprintScanner.authenticate({
+          fallbackEnabled: true,
+          description: 'This is required to access your notes.',
+        })
+          .then(() => {
+            FingerprintScanner.release()
+            resolve(true)
+          })
+          .catch((error_1) => {
+            FingerprintScanner.release()
+            if (error_1.name !== 'SystemCancel') {
+              if (error_1.name !== 'UserCancel') {
+                Alert.alert('Unsuccessful')
+              } else {
+                Alert.alert('Unsuccessful', 'Authentication failed. Tap to try again.')
+              }
+            }
+            resolve(false)
+          })
+      }
+    })
+  }
+
   getRawKeychainValue(): Promise<RawKeychainValue | null | undefined> {
     return Keychain.getKeys()
   }
diff --git a/packages/services/src/Domain/Device/MobileDeviceInterface.ts b/packages/services/src/Domain/Device/MobileDeviceInterface.ts
index 68d2d9061..87315064b 100644
--- a/packages/services/src/Domain/Device/MobileDeviceInterface.ts
+++ b/packages/services/src/Domain/Device/MobileDeviceInterface.ts
@@ -9,4 +9,5 @@ export interface MobileDeviceInterface extends DeviceInterface {
   setAndroidScreenshotPrivacy(enable: boolean): Promise<void>
   getMobileScreenshotPrivacyEnabled(): Promise<boolean | undefined>
   setMobileScreenshotPrivacyEnabled(isEnabled: boolean): Promise<void>
+  authenticateWithBiometrics(): Promise<boolean>
 }
diff --git a/packages/web/src/javascripts/Components/ChallengeModal/ChallengeModal.tsx b/packages/web/src/javascripts/Components/ChallengeModal/ChallengeModal.tsx
index e8b3356c3..a00043a5b 100644
--- a/packages/web/src/javascripts/Components/ChallengeModal/ChallengeModal.tsx
+++ b/packages/web/src/javascripts/Components/ChallengeModal/ChallengeModal.tsx
@@ -5,6 +5,7 @@ import {
   Challenge,
   ChallengePrompt,
   ChallengeReason,
+  ChallengeValidation,
   ChallengeValue,
   removeFromArray,
 } from '@standardnotes/snjs'
@@ -17,6 +18,7 @@ import LockscreenWorkspaceSwitcher from './LockscreenWorkspaceSwitcher'
 import { ApplicationGroup } from '@/Application/ApplicationGroup'
 import { ViewControllerManager } from '@/Controllers/ViewControllerManager'
 import { ChallengeModalValues } from './ChallengeModalValues'
+import { InputValue } from './InputValue'
 
 type Props = {
   application: WebApplication
@@ -64,9 +66,11 @@ const ChallengeModal: FunctionComponent<Props> = ({
   const [isProcessing, setIsProcessing] = useState(false)
   const [, setProcessingPrompts] = useState<ChallengePrompt[]>([])
   const [bypassModalFocusLock, setBypassModalFocusLock] = useState(false)
+
   const shouldShowForgotPasscode = [ChallengeReason.ApplicationUnlock, ChallengeReason.Migration].includes(
     challenge.reason,
   )
+
   const shouldShowWorkspaceSwitcher = challenge.reason === ChallengeReason.ApplicationUnlock
 
   const submit = useCallback(() => {
@@ -106,7 +110,7 @@ const ChallengeModal: FunctionComponent<Props> = ({
   }, [application, challenge, isProcessing, isSubmitting, values])
 
   const onValueChange = useCallback(
-    (value: string | number, prompt: ChallengePrompt) => {
+    (value: InputValue['value'], prompt: ChallengePrompt) => {
       const newValues = { ...values }
       newValues[prompt.id].invalid = false
       newValues[prompt.id].value = value
@@ -169,6 +173,17 @@ const ChallengeModal: FunctionComponent<Props> = ({
     }
   }, [application, challenge, onDismiss])
 
+  const biometricPrompt = challenge.prompts.find((prompt) => prompt.validation === ChallengeValidation.Biometric)
+  const hasOnlyBiometricPrompt = challenge.prompts.length === 1 && !!biometricPrompt
+  const hasBiometricPromptValue = biometricPrompt && values[biometricPrompt.id].value
+
+  useEffect(() => {
+    const shouldAutoSubmit = hasOnlyBiometricPrompt && hasBiometricPromptValue
+    if (shouldAutoSubmit) {
+      submit()
+    }
+  }, [hasBiometricPromptValue, hasOnlyBiometricPrompt, submit])
+
   if (!challenge.prompts) {
     return null
   }
@@ -201,11 +216,9 @@ const ChallengeModal: FunctionComponent<Props> = ({
         )}
         <ProtectedIllustration className="mb-4 h-30 w-30" />
         <div className="mb-3 max-w-76 text-center text-lg font-bold">{challenge.heading}</div>
-
         {challenge.subheading && (
           <div className="break-word mb-4 max-w-76 text-center text-sm">{challenge.subheading}</div>
         )}
-
         <form
           className="flex min-w-76 flex-col items-center"
           onSubmit={(e) => {
@@ -215,6 +228,7 @@ const ChallengeModal: FunctionComponent<Props> = ({
         >
           {challenge.prompts.map((prompt, index) => (
             <ChallengeModalPrompt
+              application={application}
               key={prompt.id}
               prompt={prompt}
               values={values}
diff --git a/packages/web/src/javascripts/Components/ChallengeModal/ChallengePrompt.tsx b/packages/web/src/javascripts/Components/ChallengeModal/ChallengePrompt.tsx
index 92b27137a..df1955725 100644
--- a/packages/web/src/javascripts/Components/ChallengeModal/ChallengePrompt.tsx
+++ b/packages/web/src/javascripts/Components/ChallengeModal/ChallengePrompt.tsx
@@ -1,25 +1,50 @@
-import { ChallengePrompt, ChallengeValidation, ProtectionSessionDurations } from '@standardnotes/snjs'
+import {
+  ChallengePrompt,
+  ChallengeValidation,
+  MobileDeviceInterface,
+  ProtectionSessionDurations,
+} from '@standardnotes/snjs'
 import { FunctionComponent, useEffect, useRef } from 'react'
 import DecoratedInput from '@/Components/Input/DecoratedInput'
 import DecoratedPasswordInput from '@/Components/Input/DecoratedPasswordInput'
 import { ChallengeModalValues } from './ChallengeModalValues'
+import Button from '../Button/Button'
+import { WebApplication } from '@/Application/Application'
+import { InputValue } from './InputValue'
 
 type Props = {
+  application: WebApplication
   prompt: ChallengePrompt
   values: ChallengeModalValues
   index: number
-  onValueChange: (value: string | number, prompt: ChallengePrompt) => void
+  onValueChange: (value: InputValue['value'], prompt: ChallengePrompt) => void
   isInvalid: boolean
 }
 
-const ChallengeModalPrompt: FunctionComponent<Props> = ({ prompt, values, index, onValueChange, isInvalid }) => {
+const ChallengeModalPrompt: FunctionComponent<Props> = ({
+  application,
+  prompt,
+  values,
+  index,
+  onValueChange,
+  isInvalid,
+}) => {
   const inputRef = useRef<HTMLInputElement>(null)
+  const biometricsButtonRef = useRef<HTMLButtonElement>(null)
 
   useEffect(() => {
-    if (index === 0) {
+    const isNotFirstPrompt = index !== 0
+
+    if (isNotFirstPrompt) {
+      return
+    }
+
+    if (prompt.validation === ChallengeValidation.Biometric) {
+      biometricsButtonRef.current?.click()
+    } else {
       inputRef.current?.focus()
     }
-  }, [index])
+  }, [index, prompt.validation])
 
   useEffect(() => {
     if (isInvalid) {
@@ -61,6 +86,22 @@ const ChallengeModalPrompt: FunctionComponent<Props> = ({ prompt, values, index,
             })}
           </div>
         </div>
+      ) : prompt.validation === ChallengeValidation.Biometric ? (
+        <div className="min-w-76">
+          <Button
+            primary
+            fullWidth
+            onClick={async () => {
+              const authenticated = await (
+                application.deviceInterface as MobileDeviceInterface
+              ).authenticateWithBiometrics()
+              onValueChange(authenticated, prompt)
+            }}
+            ref={biometricsButtonRef}
+          >
+            Tap to use biometrics
+          </Button>
+        </div>
       ) : prompt.secureTextEntry ? (
         <DecoratedPasswordInput
           ref={inputRef}