feat: wire up passphrase cache

Currently has horrible UX and is behind an experimental feature flag

app/src/main/java/app/passwordstore/data/crypto/CryptoRepository.kt

@@ -18,7 +18,6 @@ import app.passwordstore.util.settings.PreferenceKeys
 import com.github.michaelbull.result.Result
 import com.github.michaelbull.result.getAll
 import com.github.michaelbull.result.mapBoth
-import com.github.michaelbull.result.unwrap
 import java.io.ByteArrayInputStream
 import java.io.ByteArrayOutputStream
 import javax.inject.Inject
@@ -41,9 +40,10 @@ constructor(
 
   suspend fun decrypt(
     password: String,
+    identities: List<GpgIdentifier>,
     message: ByteArrayInputStream,
     out: ByteArrayOutputStream,
-  ) = withContext(dispatcherProvider.io()) { decryptPgp(password, message, out) }
+  ) = withContext(dispatcherProvider.io()) { decryptPgp(password, identities, message, out) }
 
   suspend fun encrypt(
     identities: List<GpgIdentifier>,
@@ -53,11 +53,12 @@ constructor(
 
   private suspend fun decryptPgp(
     password: String,
+    identities: List<GpgIdentifier>,
     message: ByteArrayInputStream,
     out: ByteArrayOutputStream,
   ): Result<Unit, CryptoHandlerException> {
+    val keys = identities.map { id -> pgpKeyManager.getKeyById(id) }.getAll()
     val decryptionOptions = PGPDecryptOptions.Builder().build()
-    val keys = pgpKeyManager.getAllKeys().unwrap()
     return pgpCryptoHandler.decrypt(keys, password, message, out, decryptionOptions)
   }
 

app/src/main/java/app/passwordstore/ui/autofill/AutofillDecryptActivity.kt

@@ -13,13 +13,17 @@ import android.os.Bundle
 import android.view.autofill.AutofillManager
 import androidx.annotation.RequiresApi
 import androidx.lifecycle.lifecycleScope
+import app.passwordstore.data.crypto.GPGPassphraseCache
 import app.passwordstore.data.passfile.PasswordEntry
 import app.passwordstore.ui.crypto.BasePgpActivity
 import app.passwordstore.ui.crypto.PasswordDialog
+import app.passwordstore.util.auth.BiometricAuthenticator
 import app.passwordstore.util.autofill.AutofillPreferences
 import app.passwordstore.util.autofill.AutofillResponseBuilder
 import app.passwordstore.util.autofill.DirectoryStructure
 import app.passwordstore.util.extensions.asLog
+import app.passwordstore.util.features.Feature.EnableGPGPassphraseCache
+import app.passwordstore.util.features.Features
 import com.github.androidpasswordstore.autofillparser.AutofillAction
 import com.github.androidpasswordstore.autofillparser.Credentials
 import com.github.michaelbull.result.getOrElse
@@ -77,6 +81,8 @@ class AutofillDecryptActivity : BasePgpActivity() {
   }
 
   @Inject lateinit var passwordEntryFactory: PasswordEntry.Factory
+  @Inject lateinit var features: Features
+  @Inject lateinit var passphraseCache: GPGPassphraseCache
 
   private lateinit var directoryStructure: DirectoryStructure
 
@@ -101,18 +107,46 @@ class AutofillDecryptActivity : BasePgpActivity() {
     directoryStructure = AutofillPreferences.directoryStructure(this)
     logcat { action.toString() }
     requireKeysExist {
-      val dialog = PasswordDialog()
-      lifecycleScope.launch {
-        withContext(Dispatchers.Main) {
-          dialog.password.collectLatest { value ->
-            if (value != null) {
-              decrypt(File(filePath), clientState, action, value)
+      val gpgIdentifiers = getGpgIdentifiers("") ?: return@requireKeysExist
+      if (
+        BiometricAuthenticator.canAuthenticate(this) && features.isEnabled(EnableGPGPassphraseCache)
+      ) {
+        BiometricAuthenticator.authenticate(this) { authResult ->
+          if (authResult is BiometricAuthenticator.Result.Success) {
+            lifecycleScope.launch {
+              val cachedPassphrase =
+                passphraseCache.retrieveCachedPassphrase(
+                  this@AutofillDecryptActivity,
+                  gpgIdentifiers.first()
+                )
+              if (cachedPassphrase != null) {
+                decrypt(File(filePath), clientState, action, cachedPassphrase)
+              } else {
+                askPassphrase(filePath, clientState, action)
+              }
             }
+          } else {
+            askPassphrase(filePath, clientState, action)
+          }
+        }
+      } else {
+        askPassphrase(filePath, clientState, action)
+      }
+    }
+  }
+
+  private fun askPassphrase(filePath: String, clientState: Bundle, action: AutofillAction) {
+    val dialog = PasswordDialog()
+    lifecycleScope.launch {
+      withContext(Dispatchers.Main) {
+        dialog.password.collectLatest { value ->
+          if (value != null) {
+            decrypt(File(filePath), clientState, action, value)
           }
         }
       }
-      dialog.show(supportFragmentManager, "PASSWORD_DIALOG")
     }
+    dialog.show(supportFragmentManager, "PASSWORD_DIALOG")
   }
 
   private suspend fun decrypt(
@@ -143,6 +177,7 @@ class AutofillDecryptActivity : BasePgpActivity() {
   }
 
   private suspend fun decryptCredential(file: File, password: String): Credentials? {
+    val gpgIdentifiers = getGpgIdentifiers("") ?: return null
     runCatching { file.readBytes().inputStream() }
       .onFailure { e ->
         logcat(ERROR) { e.asLog("File to decrypt not found") }
@@ -154,6 +189,7 @@ class AutofillDecryptActivity : BasePgpActivity() {
               val outputStream = ByteArrayOutputStream()
               repository.decrypt(
                 password,
+                gpgIdentifiers,
                 encryptedInput,
                 outputStream,
               )

app/src/main/java/app/passwordstore/ui/crypto/DecryptActivity.kt

@@ -11,13 +11,18 @@ import android.view.Menu
 import android.view.MenuItem
 import androidx.lifecycle.lifecycleScope
 import app.passwordstore.R
+import app.passwordstore.crypto.GpgIdentifier
+import app.passwordstore.data.crypto.GPGPassphraseCache
 import app.passwordstore.data.passfile.PasswordEntry
 import app.passwordstore.data.password.FieldItem
 import app.passwordstore.databinding.DecryptLayoutBinding
 import app.passwordstore.ui.adapters.FieldItemAdapter
+import app.passwordstore.util.auth.BiometricAuthenticator
 import app.passwordstore.util.extensions.getString
 import app.passwordstore.util.extensions.unsafeLazy
 import app.passwordstore.util.extensions.viewBinding
+import app.passwordstore.util.features.Feature.EnableGPGPassphraseCache
+import app.passwordstore.util.features.Features
 import app.passwordstore.util.settings.Constants
 import app.passwordstore.util.settings.PreferenceKeys
 import com.github.michaelbull.result.Err
@@ -28,7 +33,6 @@ import java.io.ByteArrayOutputStream
 import java.io.File
 import javax.inject.Inject
 import kotlin.time.Duration.Companion.seconds
-import kotlin.time.ExperimentalTime
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.flow.first
@@ -39,14 +43,14 @@ import kotlinx.coroutines.withContext
 import logcat.LogPriority.ERROR
 import logcat.logcat
 
-@OptIn(ExperimentalTime::class)
 @AndroidEntryPoint
 class DecryptActivity : BasePgpActivity() {
 
   private val binding by viewBinding(DecryptLayoutBinding::inflate)
   private val relativeParentPath by unsafeLazy { getParentPath(fullPath, repoPath) }
   @Inject lateinit var passwordEntryFactory: PasswordEntry.Factory
-
+  @Inject lateinit var passphraseCache: GPGPassphraseCache
+  @Inject lateinit var features: Features
   private var passwordEntry: PasswordEntry? = null
   private var retries = 0
 
@@ -63,7 +67,16 @@ class DecryptActivity : BasePgpActivity() {
         true
       }
     }
-    requireKeysExist { askPassphrase(isError = false) }
+    if (
+      BiometricAuthenticator.canAuthenticate(this@DecryptActivity) &&
+        features.isEnabled(EnableGPGPassphraseCache)
+    ) {
+      BiometricAuthenticator.authenticate(this@DecryptActivity) { authResult ->
+        requireKeysExist { decrypt(isError = false, authResult) }
+      }
+    } else {
+      requireKeysExist { decrypt(isError = false, BiometricAuthenticator.Result.Cancelled) }
+    }
   }
 
   override fun onCreateOptionsMenu(menu: Menu): Boolean {
@@ -134,7 +147,28 @@ class DecryptActivity : BasePgpActivity() {
     )
   }
 
-  private fun askPassphrase(isError: Boolean) {
+  private fun decrypt(isError: Boolean, authResult: BiometricAuthenticator.Result) {
+    val gpgIdentifiers = getGpgIdentifiers("") ?: return
+    lifecycleScope.launch(dispatcherProvider.main()) {
+      if (authResult is BiometricAuthenticator.Result.Success) {
+        val cachedPassphrase =
+          passphraseCache.retrieveCachedPassphrase(this@DecryptActivity, gpgIdentifiers.first())
+        if (cachedPassphrase != null) {
+          decryptWithCachedPassphrase(cachedPassphrase, gpgIdentifiers, authResult)
+        } else {
+          askPassphrase(isError, gpgIdentifiers, authResult)
+        }
+      } else {
+        askPassphrase(isError, gpgIdentifiers, authResult)
+      }
+    }
+  }
+
+  private fun askPassphrase(
+    isError: Boolean,
+    gpgIdentifiers: List<GpgIdentifier>,
+    authResult: BiometricAuthenticator.Result,
+  ) {
     if (retries < MAX_RETRIES) {
       retries += 1
     } else {
@@ -147,16 +181,19 @@ class DecryptActivity : BasePgpActivity() {
     lifecycleScope.launch(dispatcherProvider.main()) {
       dialog.password.collectLatest { value ->
         if (value != null) {
-          when (val result = decryptWithPassphrase(value)) {
+          when (val result = decryptWithPassphrase(value, gpgIdentifiers)) {
             is Ok -> {
               val entry = passwordEntryFactory.create(result.value.toByteArray())
               passwordEntry = entry
               createPasswordUI(entry)
               startAutoDismissTimer()
+              if (authResult is BiometricAuthenticator.Result.Success) {
+                passphraseCache.cachePassphrase(this@DecryptActivity, gpgIdentifiers.first(), value)
+              }
             }
             is Err -> {
               logcat(ERROR) { result.error.stackTraceToString() }
-              askPassphrase(isError = true)
+              askPassphrase(isError = true, gpgIdentifiers, authResult)
             }
           }
         }
@@ -165,12 +202,35 @@ class DecryptActivity : BasePgpActivity() {
     dialog.show(supportFragmentManager, "PASSWORD_DIALOG")
   }
 
-  private suspend fun decryptWithPassphrase(password: String) = runCatching {
+  private suspend fun decryptWithCachedPassphrase(
+    passphrase: String,
+    identifiers: List<GpgIdentifier>,
+    authResult: BiometricAuthenticator.Result,
+  ) {
+    when (val result = decryptWithPassphrase(passphrase, identifiers)) {
+      is Ok -> {
+        val entry = passwordEntryFactory.create(result.value.toByteArray())
+        passwordEntry = entry
+        createPasswordUI(entry)
+        startAutoDismissTimer()
+      }
+      is Err -> {
+        logcat(ERROR) { result.error.stackTraceToString() }
+        decrypt(isError = true, authResult = authResult)
+      }
+    }
+  }
+
+  private suspend fun decryptWithPassphrase(
+    password: String,
+    gpgIdentifiers: List<GpgIdentifier>,
+  ) = runCatching {
     val message = withContext(dispatcherProvider.io()) { File(fullPath).readBytes().inputStream() }
     val outputStream = ByteArrayOutputStream()
     val result =
       repository.decrypt(
         password,
+        gpgIdentifiers,
         message,
         outputStream,
       )

app/src/main/java/app/passwordstore/ui/settings/PGPSettings.kt

@@ -9,6 +9,7 @@ import androidx.fragment.app.FragmentActivity
 import app.passwordstore.R
 import app.passwordstore.ui.pgp.PGPKeyListActivity
 import app.passwordstore.util.extensions.launchActivity
+import app.passwordstore.util.features.Feature
 import app.passwordstore.util.settings.PreferenceKeys
 import de.Maxr1998.modernpreferences.PreferenceScreen
 import de.Maxr1998.modernpreferences.helpers.onClick
@@ -31,6 +32,10 @@ class PGPSettings(private val activity: FragmentActivity) : SettingsProvider {
         titleRes = R.string.pref_pgp_ascii_armor_title
         persistent = true
       }
+      switch(Feature.EnableGPGPassphraseCache.configKey) {
+        titleRes = R.string.pref_title_passphrase_cache
+        defaultValue = false
+      }
     }
   }
 }

app/src/main/java/app/passwordstore/util/features/Feature.kt

@@ -22,6 +22,9 @@ enum class Feature(
 
   /** Opt into the new SSH layer implemented as a freestanding module. */
   EnableNewSSHLayer(false, "enable_new_ssh"),
+
+  /** Opt into a cache layer for GPG passphrases. */
+  EnableGPGPassphraseCache(false, "enable_gpg_passphrase_cache"),
   ;
 
   companion object {

app/src/main/res/values/strings.xml

@@ -371,4 +371,5 @@
   <string name="pgp_key_manager_no_keys_guidance">Import a key using the add button below</string>
   <string name="no_keys_imported_dialog_title">No keys imported</string>
   <string name="no_keys_imported_dialog_message">There are no PGP keys imported in the app yet, press the button below to pick a key file</string>
+  <string name="pref_title_passphrase_cache">Enable passphrase caching</string>
 </resources>