wip: decrypt files using key imported during onboarding

Signed-off-by: Aditya Wasan <adityawasan55@gmail.com>

Author: Skrilltrax

app/src/main/java/dev/msfjarvis/aps/ui/crypto/GopenpgpDecryptActivity.kt

@@ -12,6 +12,7 @@ import android.view.MenuItem
 import androidx.lifecycle.lifecycleScope
 import dagger.hilt.android.AndroidEntryPoint
 import dev.msfjarvis.aps.R
+import dev.msfjarvis.aps.data.crypto.AndroidKeyManager
 import dev.msfjarvis.aps.data.crypto.GopenpgpCryptoHandler
 import dev.msfjarvis.aps.data.passfile.PasswordEntry
 import dev.msfjarvis.aps.data.password.FieldItem
@@ -36,6 +37,7 @@ class GopenpgpDecryptActivity : BasePgpActivity() {
   private val binding by viewBinding(DecryptLayoutBinding::inflate)
   @Inject lateinit var passwordEntryFactory: PasswordEntryFactory
   @Inject lateinit var gopenpgpCrypto: GopenpgpCryptoHandler
+  @Inject lateinit var gpgKeyManager: AndroidKeyManager
   private val relativeParentPath by unsafeLazy { getParentPath(fullPath, repoPath) }
 
   private var passwordEntry: PasswordEntry? = null
@@ -125,12 +127,13 @@ class GopenpgpDecryptActivity : BasePgpActivity() {
   private fun decrypt() =
     lifecycleScope.launch {
       // TODO(msfjarvis): native methods are fallible, add error handling once out of testing
-      val message = withContext(Dispatchers.IO) { File(fullPath).readBytes() }
+      val message = withContext(Dispatchers.IO) { File(fullPath).readText() }
       val result =
         withContext(Dispatchers.IO) {
-          gopenpgpCrypto.decrypt(
-            PRIV_KEY,
-            PASS.toByteArray(charset = Charsets.UTF_8),
+          // TODO(aditya): Use .gpg-id to get the key id
+          gopenpgpCrypto.decryptFromKeyId(
+            "b950ae2813841585",
+            "12345678".toByteArray(charset = Charsets.UTF_8),
             message,
           )
         }

app/src/main/java/dev/msfjarvis/aps/ui/onboarding/fragments/GopenpgpKeySelectionFragment.kt

@@ -12,6 +12,8 @@ import androidx.activity.result.contract.ActivityResultContracts
 import androidx.core.content.edit
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.viewModels
+import androidx.lifecycle.lifecycleScope
+import com.github.ajalt.timberkt.d
 import com.github.michaelbull.result.onFailure
 import com.github.michaelbull.result.onSuccess
 import dagger.hilt.android.AndroidEntryPoint
@@ -24,6 +26,7 @@ import dev.msfjarvis.aps.util.extensions.sharedPrefs
 import dev.msfjarvis.aps.util.extensions.unsafeLazy
 import dev.msfjarvis.aps.util.extensions.viewBinding
 import dev.msfjarvis.aps.util.settings.PreferenceKeys
+import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
 
 @AndroidEntryPoint
@@ -32,19 +35,18 @@ class GopenpgpKeySelectionFragment : Fragment(R.layout.fragment_key_selection) {
   private val settings by unsafeLazy { requireActivity().applicationContext.sharedPrefs }
   private val binding by viewBinding(FragmentKeySelectionBinding::bind)
   private val viewModel: KeySelectionViewModel by viewModels()
-
-  private val gpgKeySelectAction = registerForActivityResult(ActivityResultContracts.GetContent()) { uri ->
-    if (uri == null) {
-      // TODO: Use string resources here
-      showError("No files chosen")
-      return@registerForActivityResult
-    }
-
-    val fis = requireContext().contentResolver.openInputStream(uri)
-    if (fis == null) {
-      showError("Error resolving content uri")
-      return@registerForActivityResult
-    }
+  private val gpgKeySelectAction =
+    registerForActivityResult(ActivityResultContracts.GetContent()) { uri ->
+      if (uri == null) {
+        // TODO: Use string resources here
+        showError("No files chosen")
+        return@registerForActivityResult
+      }
+      val fis = requireContext().contentResolver.openInputStream(uri)
+      if (fis == null) {
+        showError("Error resolving content uri")
+        return@registerForActivityResult
+      }
 
       viewModel.importKey(fis)
     }
@@ -53,15 +55,24 @@ class GopenpgpKeySelectionFragment : Fragment(R.layout.fragment_key_selection) {
     super.onViewCreated(view, savedInstanceState)
     binding.selectKey.setOnClickListener { gpgKeySelectAction.launch("*/*") }
 
-    viewModel.importKeyStatus.onEach { result ->
-      result.onSuccess {
-        settings.edit { putBoolean(PreferenceKeys.REPOSITORY_INITIALIZED, true) }
-        requireActivity().commitChange(getString(R.string.git_commit_gpg_id, getString(R.string.app_name)))
-        finish()
-      }.onFailure {
-        showError(it.message!!)
+    // TODO: Use new flowWithLifecycle APIs
+    viewModel
+      .importKeyStatus
+      .onEach { result ->
+        result
+          .onSuccess {
+            d { "Key imported successfully" }
+            settings.edit { putBoolean(PreferenceKeys.REPOSITORY_INITIALIZED, true) }
+            requireActivity()
+              .commitChange(getString(R.string.git_commit_gpg_id, getString(R.string.app_name)))
+            finish()
+          }
+          .onFailure {
+            d(it)
+            showError(it.message!!)
+          }
       }
-    }
+      .launchIn(viewLifecycleOwner.lifecycleScope)
   }
 
   private fun showError(message: String) {

app/src/main/java/dev/msfjarvis/aps/ui/onboarding/viewmodel/KeySelectionViewModel.kt

@@ -1,5 +1,6 @@
 package dev.msfjarvis.aps.ui.onboarding.viewmodel
 
+import android.util.Log
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.github.michaelbull.result.Err
@@ -61,9 +62,13 @@ class KeySelectionViewModel @Inject constructor(private val keyManager: KeyManag
         Regex("END .* PRIVATE KEY").containsMatchIn(lines.last()))
   }
 
-  private suspend fun createGpgIdFile(): Result<Unit, Throwable> = withContext(Dispatchers.IO) {
-    return@withContext keyManager.listKeyIds().map { keys ->
-      val idFile = File(PasswordRepository.getRepositoryDirectory(), ".gpg-id")
-      idFile.writeText((keys + "").joinToString("\n"))
+  private suspend fun createGpgIdFile(): Result<Unit, Throwable> =
+    withContext(Dispatchers.IO) {
+      return@withContext keyManager.listKeyIds().map { keys ->
+        Log.d("CreateIdFile", "$keys")
+        val idFile = File(PasswordRepository.getRepositoryDirectory(), ".gpg-id")
+        idFile.createNewFile()
+        idFile.writeText((keys + "").joinToString("\n"))
+      }
     }
 }

crypto-pgp/src/main/kotlin/dev/msfjarvis/aps/data/crypto/AndroidKeyManager.kt

@@ -3,6 +3,7 @@ package dev.msfjarvis.aps.data.crypto
 import com.github.michaelbull.result.Err
 import com.github.michaelbull.result.Result
 import com.github.michaelbull.result.runCatching
+import com.proton.Gopenpgp.crypto.Crypto
 import com.proton.Gopenpgp.crypto.Key
 import java.io.File
 import kotlinx.coroutines.CoroutineDispatcher
@@ -16,18 +17,21 @@ public class AndroidKeyManager(
 
   private val keyDir = File(filesDirPath, KeyDir)
 
-  override suspend fun addKey(stringKey: String): Result<String, Throwable> = withContext(dispatcher) {
-    return@withContext addKey(Key(stringKey))
-  }
+  override suspend fun addKey(stringKey: String): Result<String, Throwable> =
+    withContext(dispatcher) {
+      return@withContext addKey(Crypto.newKeyFromArmored(stringKey))
+    }
 
   override suspend fun addKey(key: Key): Result<String, Throwable> =
     withContext(dispatcher) {
       if (!keyDirExists())
         return@withContext Err<Throwable>(IllegalStateException("Key directory does not exist"))
 
-    return@withContext runCatching {
-      val keyFile = File(keyDir, "${key.hexKeyID}.key")
-      keyFile.writeText(key.armor())
+      return@withContext runCatching {
+        val keyFile = File(keyDir, "${key.hexKeyID}.key")
+        if (keyFile.exists()) keyFile.delete()
+
+        keyFile.writeText(key.armor())
 
         key.hexKeyID
       }

crypto-pgp/src/main/kotlin/dev/msfjarvis/aps/data/crypto/GopenpgpCryptoHandler.kt

@@ -5,12 +5,15 @@
 
 package dev.msfjarvis.aps.data.crypto
 
+import com.github.michaelbull.result.unwrap
 import com.proton.Gopenpgp.crypto.Crypto
 import com.proton.Gopenpgp.helper.Helper
 import javax.inject.Inject
 
 /** Gopenpgp backed implementation of [CryptoHandler]. */
-public class GopenpgpCryptoHandler @Inject constructor() : CryptoHandler {
+public class GopenpgpCryptoHandler
+@Inject
+constructor(private val gpgKeyManager: AndroidKeyManager) : CryptoHandler {
 
   /**
    * Decrypt the given [ciphertext] using the given PGP [privateKey] and corresponding [passphrase].
@@ -42,4 +45,24 @@ public class GopenpgpCryptoHandler @Inject constructor() : CryptoHandler {
       plaintext,
     )
   }
+
+  /**
+   * TODO: Find a better place for this method Utility method to decrypt the given [ciphertext]
+   * using the given PGP key [id] and corresponding [passphrase].
+   */
+  public suspend fun decryptFromKeyId(
+    id: String,
+    passphrase: ByteArray,
+    ciphertext: String,
+  ): ByteArray {
+    // TODO(aditya): Handle error cases
+    val key = gpgKeyManager.findKeyById(id).unwrap()
+    val message = Crypto.newPGPMessageFromArmored(ciphertext)
+    return Helper.decryptMessageArmored(
+        key.armor(),
+        passphrase,
+        message.armored,
+      )
+      .toByteArray()
+  }
 }