wip(crypto-pgpainless): add PGPKeyPair and PGPKeyManager

Signed-off-by: Aditya Wasan <adityawasan55@gmail.com>
(cherry picked from commit 02d07e9)

crypto-pgpainless/api/crypto-pgpainless.api

@@ -1,3 +1,21 @@
+public final class dev/msfjarvis/aps/crypto/PGPKeyManager : dev/msfjarvis/aps/crypto/KeyManager {
+	public fun <init> (Ljava/lang/String;Lkotlinx/coroutines/CoroutineDispatcher;)V
+	public synthetic fun addKey (Ldev/msfjarvis/aps/crypto/KeyPair;ZLkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public fun addKey (Ldev/msfjarvis/aps/crypto/PGPKeyPair;ZLkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public fun canHandle (Ljava/lang/String;)Z
+	public fun getAllKeys (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public fun getKeyById (Ljava/lang/String;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public synthetic fun removeKey (Ldev/msfjarvis/aps/crypto/KeyPair;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public fun removeKey (Ldev/msfjarvis/aps/crypto/PGPKeyPair;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+}
+
+public final class dev/msfjarvis/aps/crypto/PGPKeyPair : dev/msfjarvis/aps/crypto/KeyPair {
+	public fun <init> (Lorg/bouncycastle/openpgp/PGPSecretKey;)V
+	public fun getKeyId ()Ljava/lang/String;
+	public fun getPrivateKey ()[B
+	public fun getPublicKey ()[B
+}
+
 public final class dev/msfjarvis/aps/crypto/PGPainlessCryptoHandler : dev/msfjarvis/aps/crypto/CryptoHandler {
 	public fun <init> ()V
 	public fun canHandle (Ljava/lang/String;)Z

crypto-pgpainless/build.gradle.kts

@@ -10,8 +10,11 @@ plugins {
 
 dependencies {
   api(projects.cryptoCommon)
+  implementation(libs.androidx.annotation)
   implementation(libs.dagger.hilt.core)
   implementation(libs.kotlin.coroutines.core)
   implementation(libs.thirdparty.kotlinResult)
   implementation(libs.thirdparty.pgpainless)
+  testImplementation(libs.bundles.testDependencies)
+  testImplementation(libs.kotlin.coroutines.test)
 }

crypto-pgpainless/src/main/kotlin/dev/msfjarvis/aps/crypto/PGPKeyManager.kt

@@ -0,0 +1,106 @@
+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package dev.msfjarvis.aps.crypto
+
+import androidx.annotation.VisibleForTesting
+import com.github.michaelbull.result.Result
+import com.github.michaelbull.result.runCatching
+import java.io.File
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.withContext
+import org.pgpainless.PGPainless
+
+public class PGPKeyManager(
+  filesDir: String,
+  private val dispatcher: CoroutineDispatcher,
+) : KeyManager<PGPKeyPair> {
+
+  private val keyDir = File(filesDir, KEY_DIR_NAME)
+
+  override suspend fun addKey(key: PGPKeyPair, replace: Boolean): Result<PGPKeyPair, Throwable> =
+    withContext(dispatcher) {
+      runCatching {
+        if (!keyDirExists()) throw KeyManagerException.KeyDirectoryUnavailableException
+        val keyFile = File(keyDir, "${key.getKeyId()}.$KEY_EXTENSION")
+        if (keyFile.exists()) {
+          // Check for replace flag first and if it is false, throw an error
+          if (!replace) throw KeyManagerException.KeyAlreadyExistsException(key.getKeyId())
+          if (!keyFile.delete()) throw KeyManagerException.KeyDeletionFailedException
+        }
+
+        keyFile.writeBytes(key.getPrivateKey())
+
+        key
+      }
+    }
+
+  override suspend fun removeKey(key: PGPKeyPair): Result<PGPKeyPair, Throwable> =
+    withContext(dispatcher) {
+      runCatching {
+        if (!keyDirExists()) throw KeyManagerException.KeyDirectoryUnavailableException
+        val keyFile = File(keyDir, "${key.getKeyId()}.$KEY_EXTENSION")
+        if (keyFile.exists()) {
+          if (!keyFile.delete()) throw KeyManagerException.KeyDeletionFailedException
+        }
+
+        key
+      }
+    }
+
+  override suspend fun getKeyById(id: String): Result<PGPKeyPair, Throwable> =
+    withContext(dispatcher) {
+      runCatching {
+        if (!keyDirExists()) throw KeyManagerException.KeyDirectoryUnavailableException
+        val keys = keyDir.listFiles()
+        if (keys.isNullOrEmpty()) throw KeyManagerException.NoKeysAvailableException
+
+        for (keyFile in keys) {
+          val secretKeyRing = PGPainless.readKeyRing().secretKeyRing(keyFile.inputStream())
+          val secretKey = secretKeyRing.secretKey
+          val keyPair = PGPKeyPair(secretKey)
+          if (keyPair.getKeyId() == id) return@runCatching keyPair
+        }
+
+        throw KeyManagerException.KeyNotFoundException(id)
+      }
+    }
+
+  override suspend fun getAllKeys(): Result<List<PGPKeyPair>, Throwable> =
+    withContext(dispatcher) {
+      runCatching {
+        if (!keyDirExists()) throw KeyManagerException.KeyDirectoryUnavailableException
+        val keys = keyDir.listFiles()
+        if (keys.isNullOrEmpty()) return@runCatching listOf()
+
+        keys
+          .map { keyFile ->
+            val secretKeyRing = PGPainless.readKeyRing().secretKeyRing(keyFile.inputStream())
+            val secretKey = secretKeyRing.secretKey
+
+            PGPKeyPair(secretKey)
+          }
+          .toList()
+      }
+    }
+
+  override fun canHandle(fileName: String): Boolean {
+    // TODO: This is a temp hack for now and in future it should check that the GPGKeyManager can
+    // decrypt the file
+    return fileName.endsWith(KEY_EXTENSION)
+  }
+
+  private fun keyDirExists(): Boolean {
+    return keyDir.exists() || keyDir.mkdirs()
+  }
+
+  internal companion object {
+
+    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
+    internal const val KEY_DIR_NAME: String = "keys"
+    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
+    internal const val KEY_EXTENSION: String = "key"
+  }
+}

crypto-pgpainless/src/main/kotlin/dev/msfjarvis/aps/crypto/PGPKeyPair.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package dev.msfjarvis.aps.crypto
+
+import org.bouncycastle.openpgp.PGPSecretKey
+
+public class PGPKeyPair(private val secretKey: PGPSecretKey) : KeyPair {
+
+  init {
+    if (secretKey.isPrivateKeyEmpty) throw KeyPairException.PrivateKeyUnavailableException
+  }
+
+  override fun getPrivateKey(): ByteArray {
+    return secretKey.encoded
+  }
+  override fun getPublicKey(): ByteArray {
+    return secretKey.publicKey.encoded
+  }
+  override fun getKeyId(): String {
+    return secretKey.keyID.toString()
+  }
+}

crypto-pgpainless/src/main/kotlin/dev/msfjarvis/aps/crypto/utils/CryptoConstants.kt

@@ -0,0 +1,14 @@
+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package dev.msfjarvis.aps.crypto.utils
+
+internal object CryptoConstants {
+  internal const val KEY_PASSPHRASE = "hunter2"
+  internal const val PLAIN_TEXT = "encryption worthy content"
+  internal const val KEY_NAME = "John Doe"
+  internal const val KEY_EMAIL = "john.doe@example.com"
+  internal const val KEY_ID = "04ace699d5b15b7e"
+}

crypto-pgpainless/src/test/kotlin/dev/msfjarvis/aps/crypto/PGPKeyPairTest.kt

@@ -0,0 +1,44 @@
+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package dev.msfjarvis.aps.crypto
+
+import dev.msfjarvis.aps.crypto.utils.CryptoConstants
+import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
+import org.junit.Test
+import org.pgpainless.PGPainless
+
+public class GPGKeyPairTest {
+
+  @Test
+  public fun testIfKeyIdIsCorrect() {
+    val secretKey = PGPainless.readKeyRing().secretKeyRing(getKey()).secretKey
+    val keyPair = PGPKeyPair(secretKey)
+
+    assertEquals(CryptoConstants.KEY_ID, keyPair.getKeyId())
+  }
+
+  @Test
+  public fun testBuildingKeyPairWithoutPrivateKey() {
+    assertFailsWith<KeyPairException.PrivateKeyUnavailableException> {
+      // Get public key object from private key
+      val publicKey = PGPainless.readKeyRing().secretKeyRing(getKey()).publicKey
+
+      // Create secret key ring from public key
+      val secretKeyRing = PGPainless.readKeyRing().secretKeyRing(publicKey.encoded)
+
+      // Get secret key from key ring
+      val publicSecretKey = secretKeyRing.secretKey
+
+      // Try creating a KeyPair from public key
+      val keyPair = PGPKeyPair(publicSecretKey)
+
+      keyPair.getPrivateKey()
+    }
+  }
+
+  private fun getKey(): String = this::class.java.classLoader.getResource("private_key").readText()
+}

crypto-pgpainless/src/test/resources/private_key

@@ -0,0 +1,18 @@
+-----BEGIN PGP PRIVATE KEY BLOCK-----
+Version: GopenPGP 2.1.9
+Comment: https://gopenpgp.org
+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+=Sfsa
+-----END PGP PRIVATE KEY BLOCK-----