feat(RAMF): Implement payload unwrapping (#68)

src/main/kotlin/tech/relaycorp/relaynet/messages/Cargo.kt

@@ -1,5 +1,6 @@
 package tech.relaycorp.relaynet.messages
 
+import tech.relaycorp.relaynet.messages.payloads.CargoMessageSet
 import tech.relaycorp.relaynet.ramf.RAMFException
 import tech.relaycorp.relaynet.ramf.RAMFMessage
 import tech.relaycorp.relaynet.ramf.RAMFMessageCompanion
@@ -21,7 +22,7 @@ class Cargo(
     creationDate: ZonedDateTime? = null,
     ttl: Int? = null,
     senderCertificateChain: Set<Certificate>? = null
-) : RAMFMessage(
+) : RAMFMessage<CargoMessageSet>(
     SERIALIZER,
     recipientAddress,
     payload,
@@ -31,6 +32,9 @@ class Cargo(
     ttl,
     senderCertificateChain
 ) {
+    override fun deserializePayload(payloadPlaintext: ByteArray) =
+        CargoMessageSet.deserialize(payloadPlaintext)
+
     companion object : RAMFMessageCompanion<Cargo> {
         /**
          * Deserialize cargo

src/main/kotlin/tech/relaycorp/relaynet/messages/CargoCollectionAuthorization.kt

@@ -1,5 +1,6 @@
 package tech.relaycorp.relaynet.messages
 
+import tech.relaycorp.relaynet.messages.payloads.EmptyPayloadPlaintext
 import tech.relaycorp.relaynet.ramf.RAMFException
 import tech.relaycorp.relaynet.ramf.RAMFMessage
 import tech.relaycorp.relaynet.ramf.RAMFMessageCompanion
@@ -21,7 +22,7 @@ class CargoCollectionAuthorization(
     creationDate: ZonedDateTime? = null,
     ttl: Int? = null,
     senderCertificateChain: Set<Certificate>? = null
-) : RAMFMessage(
+) : RAMFMessage<EmptyPayloadPlaintext>(
     SERIALIZER,
     recipientAddress,
     payload,
@@ -31,6 +32,9 @@ class CargoCollectionAuthorization(
     ttl,
     senderCertificateChain
 ) {
+    override fun deserializePayload(payloadPlaintext: ByteArray) =
+        EmptyPayloadPlaintext.deserialize(payloadPlaintext)
+
     companion object : RAMFMessageCompanion<CargoCollectionAuthorization> {
         /**
          * Deserialize a CCA

src/main/kotlin/tech/relaycorp/relaynet/messages/Parcel.kt

@@ -1,5 +1,6 @@
 package tech.relaycorp.relaynet.messages
 
+import tech.relaycorp.relaynet.messages.payloads.ServiceMessage
 import tech.relaycorp.relaynet.ramf.RAMFException
 import tech.relaycorp.relaynet.ramf.RAMFMessage
 import tech.relaycorp.relaynet.ramf.RAMFMessageCompanion
@@ -21,7 +22,7 @@ class Parcel(
     creationDate: ZonedDateTime? = null,
     ttl: Int? = null,
     senderCertificateChain: Set<Certificate>? = null
-) : RAMFMessage(
+) : RAMFMessage<ServiceMessage>(
     SERIALIZER,
     recipientAddress,
     payload,
@@ -31,6 +32,10 @@ class Parcel(
     ttl,
     senderCertificateChain
 ) {
+    override fun deserializePayload(payloadPlaintext: ByteArray): ServiceMessage {
+        TODO("Not yet implemented")
+    }
+
     companion object : RAMFMessageCompanion<Parcel> {
         /**
          * Deserialize parcel

src/main/kotlin/tech/relaycorp/relaynet/messages/payloads/EmptyPayloadPlaintext.kt

@@ -0,0 +1,28 @@
+package tech.relaycorp.relaynet.messages.payloads
+
+import tech.relaycorp.relaynet.ramf.RAMFException
+
+/**
+ * Empty payload plaintext.
+ */
+class EmptyPayloadPlaintext : PayloadPlaintext {
+    /**
+     * Serialize empty payload plaintext.
+     */
+    override fun serialize() = ByteArray(0)
+
+    companion object {
+        /**
+         * Deserialize empty payload plaintext.
+         *
+         * @throws RAMFException if `serialization` is not empty
+         */
+        @Throws(RAMFException::class)
+        fun deserialize(serialization: ByteArray): EmptyPayloadPlaintext {
+            if (serialization.isNotEmpty()) {
+                throw RAMFException("Payload is not empty")
+            }
+            return EmptyPayloadPlaintext()
+        }
+    }
+}

src/main/kotlin/tech/relaycorp/relaynet/messages/payloads/ServiceMessage.kt

@@ -0,0 +1,7 @@
+package tech.relaycorp.relaynet.messages.payloads
+
+class ServiceMessage : PayloadPlaintext {
+    override fun serialize(): ByteArray {
+        TODO("Not yet implemented")
+    }
+}

src/main/kotlin/tech/relaycorp/relaynet/ramf/RAMFMessage.kt

@@ -2,6 +2,10 @@ package tech.relaycorp.relaynet.ramf
 
 import tech.relaycorp.relaynet.HashingAlgorithm
 import tech.relaycorp.relaynet.dateToZonedDateTime
+import tech.relaycorp.relaynet.messages.payloads.PayloadPlaintext
+import tech.relaycorp.relaynet.wrappers.cms.EnvelopedData
+import tech.relaycorp.relaynet.wrappers.cms.EnvelopedDataException
+import tech.relaycorp.relaynet.wrappers.cms.SessionlessEnvelopedData
 import tech.relaycorp.relaynet.wrappers.x509.Certificate
 import tech.relaycorp.relaynet.wrappers.x509.CertificateException
 import java.net.MalformedURLException
@@ -32,7 +36,7 @@ private val PRIVATE_ADDRESS_REGEX = "^0[a-f0-9]+$".toRegex()
  * @property payload The payload
  * @property senderCertificate The sender's Relaynet PKI certificate
  */
-abstract class RAMFMessage internal constructor(
+abstract class RAMFMessage<Payload : PayloadPlaintext> internal constructor(
     private val serializer: RAMFSerializer,
     val recipientAddress: String,
     val payload: ByteArray,
@@ -131,6 +135,23 @@ abstract class RAMFMessage internal constructor(
         validateRecipientAddress()
     }
 
+    /**
+     * Decrypt and deserialize payload.
+     *
+     * @throws EnvelopedDataException if the CMS EnvelopedData value is invalid or the
+     *      `privateKey` is invalid.
+     * @throws RAMFException if the plaintext is invalid.
+     */
+    @Throws(RAMFException::class, EnvelopedDataException::class)
+    fun unwrapPayload(privateKey: PrivateKey): Payload {
+        val envelopedData = EnvelopedData.deserialize(payload) as SessionlessEnvelopedData
+        val plaintext = envelopedData.decrypt(privateKey)
+        return deserializePayload(plaintext)
+    }
+
+    @Throws(RAMFException::class)
+    internal abstract fun deserializePayload(payloadPlaintext: ByteArray): Payload
+
     private fun validateTiming() {
         val now = ZonedDateTime.now(UTC)
         if (now < creationDate) {

src/main/kotlin/tech/relaycorp/relaynet/ramf/RAMFMessageCompanion.kt

@@ -2,7 +2,7 @@ package tech.relaycorp.relaynet.ramf
 
 import java.io.InputStream
 
-internal interface RAMFMessageCompanion<Message : RAMFMessage> {
+internal interface RAMFMessageCompanion<Message : RAMFMessage<*>> {
     fun deserialize(serialization: ByteArray): Message
     fun deserialize(serialization: InputStream): Message
 }

src/main/kotlin/tech/relaycorp/relaynet/ramf/RAMFSerializer.kt

@@ -47,7 +47,7 @@ private data class FieldSet(
 
 internal class RAMFSerializer(val concreteMessageType: Byte, val concreteMessageVersion: Byte) {
     fun serialize(
-        message: RAMFMessage,
+        message: RAMFMessage<*>,
         signerPrivateKey: PrivateKey,
         hashingAlgorithm: HashingAlgorithm? = null
     ): ByteArray {
@@ -71,7 +71,7 @@ internal class RAMFSerializer(val concreteMessageType: Byte, val concreteMessage
     }
 
     @Throws(IOException::class)
-    private fun serializeMessage(message: RAMFMessage): ByteArray {
+    private fun serializeMessage(message: RAMFMessage<*>): ByteArray {
         val reverseOS = ReverseByteArrayOutputStream(1000, true)
         var codeLength = 0
 

src/main/kotlin/tech/relaycorp/relaynet/wrappers/cms/EnvelopedDataException.kt

@@ -2,5 +2,5 @@ package tech.relaycorp.relaynet.wrappers.cms
 
 import tech.relaycorp.relaynet.RelaynetException
 
-internal class EnvelopedDataException(message: String, cause: Throwable? = null) :
+class EnvelopedDataException internal constructor(message: String, cause: Throwable? = null) :
     RelaynetException(message, cause)

src/test/kotlin/tech/relaycorp/relaynet/CryptoUtils.kt

@@ -1,5 +1,6 @@
 package tech.relaycorp.relaynet
 
+import tech.relaycorp.relaynet.wrappers.generateRSAKeyPair
 import tech.relaycorp.relaynet.wrappers.x509.Certificate
 import java.security.MessageDigest
 import java.security.PrivateKey
@@ -28,3 +29,6 @@ fun issueStubCertificate(
         issuerCertificate = issuerCertificate
     )
 }
+
+val KEY_PAIR = generateRSAKeyPair()
+val CERTIFICATE = issueStubCertificate(KEY_PAIR.public, KEY_PAIR.private)

src/test/kotlin/tech/relaycorp/relaynet/messages/CargoCollectionAuthorizationTest.kt

@@ -1,27 +1,24 @@
 package tech.relaycorp.relaynet.messages
 
-import org.junit.jupiter.api.Nested
-import org.junit.jupiter.api.TestFactory
-import tech.relaycorp.relaynet.ramf.makeRAMFMessageCompanionTests
-import tech.relaycorp.relaynet.ramf.makeRAMFMessageConstructorTests
+import tech.relaycorp.relaynet.CERTIFICATE
+import tech.relaycorp.relaynet.ramf.RAMFSerializationTestCase
 import tech.relaycorp.relaynet.wrappers.x509.Certificate
+import kotlin.test.Test
 
-class CargoCollectionAuthorizationTest {
-    @TestFactory
-    fun makeConstructorTests() =
-        makeRAMFMessageConstructorTests(
-            ::CargoCollectionAuthorization,
-            { r: String, p: ByteArray, s: Certificate -> CargoCollectionAuthorization(r, p, s) },
-            0x44,
-            0x00
+internal class CargoCollectionAuthorizationTest :
+    RAMFSerializationTestCase<CargoCollectionAuthorization>(
+        ::CargoCollectionAuthorization,
+        { r: String, p: ByteArray, s: Certificate -> CargoCollectionAuthorization(r, p, s) },
+        0x44,
+        0x00,
+        CargoCollectionAuthorization.Companion
+    ) {
+    @Test
+    fun `Payload deserialization should be delegated to EmptyPayloadPlaintext`() {
+        val cca = CargoCollectionAuthorization(
+            "https://gb.relaycorp.tech", "".toByteArray(), CERTIFICATE
         )
 
-    @Nested
-    inner class Companion {
-        @TestFactory
-        fun makeDeserializationTests() = makeRAMFMessageCompanionTests(
-            CargoCollectionAuthorization.Companion,
-            ::CargoCollectionAuthorization
-        )
+        cca.deserializePayload("".toByteArray())
     }
 }

src/test/kotlin/tech/relaycorp/relaynet/messages/CargoTest.kt

@@ -1,23 +1,29 @@
 package tech.relaycorp.relaynet.messages
 
-import org.junit.jupiter.api.Nested
-import org.junit.jupiter.api.TestFactory
-import tech.relaycorp.relaynet.ramf.makeRAMFMessageCompanionTests
-import tech.relaycorp.relaynet.ramf.makeRAMFMessageConstructorTests
+import tech.relaycorp.relaynet.CERTIFICATE
+import tech.relaycorp.relaynet.messages.payloads.CargoMessageSet
+import tech.relaycorp.relaynet.ramf.RAMFSerializationTestCase
 import tech.relaycorp.relaynet.wrappers.x509.Certificate
+import kotlin.test.Test
+import kotlin.test.assertEquals
 
-class CargoTest {
-    @TestFactory
-    fun makeConstructorTests() = makeRAMFMessageConstructorTests(
-        ::Cargo,
-        { r: String, p: ByteArray, s: Certificate -> Cargo(r, p, s) },
-        0x43,
-        0x00
-    )
+internal class CargoTest : RAMFSerializationTestCase<Cargo>(
+    ::Cargo,
+    { r: String, p: ByteArray, s: Certificate -> Cargo(r, p, s) },
+    0x43,
+    0x00,
+    Cargo.Companion
+) {
+    @Test
+    fun `Payload deserialization should be delegated to CargoMessageSet`() {
+        val cargoMessageSet = CargoMessageSet(arrayOf("msg1".toByteArray(), "msg2".toByteArray()))
+        val cargo = Cargo("https://gb.relaycorp.tech", "".toByteArray(), CERTIFICATE)
 
-    @Nested
-    inner class Companion {
-        @TestFactory
-        fun makeDeserializationTests() = makeRAMFMessageCompanionTests(Cargo.Companion, ::Cargo)
+        val payloadDeserialized = cargo.deserializePayload(cargoMessageSet.serialize())
+
+        assertEquals(
+            cargoMessageSet.messages.map { it.asList() },
+            payloadDeserialized.messages.map { it.asList() }
+        )
     }
 }

src/test/kotlin/tech/relaycorp/relaynet/messages/ParcelTest.kt

@@ -1,23 +1,23 @@
 package tech.relaycorp.relaynet.messages
 
-import org.junit.jupiter.api.Nested
-import org.junit.jupiter.api.TestFactory
-import tech.relaycorp.relaynet.ramf.makeRAMFMessageCompanionTests
-import tech.relaycorp.relaynet.ramf.makeRAMFMessageConstructorTests
+import org.junit.jupiter.api.assertThrows
+import tech.relaycorp.relaynet.CERTIFICATE
+import tech.relaycorp.relaynet.ramf.RAMFSerializationTestCase
 import tech.relaycorp.relaynet.wrappers.x509.Certificate
+import kotlin.test.Test
 
-class ParcelTest {
-    @TestFactory
-    fun makeConstructorTests() = makeRAMFMessageConstructorTests(
-        ::Parcel,
-        { r: String, p: ByteArray, s: Certificate -> Parcel(r, p, s) },
-        0x50,
-        0x00
-    )
+internal class ParcelTest : RAMFSerializationTestCase<Parcel>(
+    ::Parcel,
+    { r: String, p: ByteArray, s: Certificate -> Parcel(r, p, s) },
+    0x50,
+    0x00,
+    Parcel.Companion
+) {
+    @Test
+    fun `Payload deserialization should be delegated to ServiceMessage`() {
+        val parcel = Parcel("https://gb.relaycorp.tech", "".toByteArray(), CERTIFICATE)
 
-    @Nested
-    inner class Companion {
-        @TestFactory
-        fun makeDeserializationTests() = makeRAMFMessageCompanionTests(Parcel.Companion, ::Parcel)
+        // TODO
+        assertThrows<NotImplementedError> { parcel.deserializePayload("invalid".toByteArray()) }
     }
 }

src/test/kotlin/tech/relaycorp/relaynet/messages/payloads/EmptyPayloadPlaintextTest.kt

@@ -0,0 +1,36 @@
+package tech.relaycorp.relaynet.messages.payloads
+
+import org.junit.jupiter.api.Nested
+import org.junit.jupiter.api.assertThrows
+import tech.relaycorp.relaynet.ramf.RAMFException
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+internal class EmptyPayloadPlaintextTest {
+    @Nested
+    inner class Serialize {
+        @Test
+        fun `An empty ByteArray should be returned`() {
+            val payloadPlaintext = EmptyPayloadPlaintext()
+
+            assertEquals(0, payloadPlaintext.serialize().size)
+        }
+    }
+
+    @Nested
+    inner class Deserialize {
+        @Test
+        fun `An empty buffer should be accepted`() {
+            EmptyPayloadPlaintext.deserialize(ByteArray(0))
+        }
+
+        @Test
+        fun `An error should be thrown if buffer is not empty`() {
+            val exception = assertThrows<RAMFException> {
+                EmptyPayloadPlaintext.deserialize("a".toByteArray())
+            }
+
+            assertEquals("Payload is not empty", exception.message)
+        }
+    }
+}

src/test/kotlin/tech/relaycorp/relaynet/messages/payloads/ServiceMessageTest.kt

@@ -0,0 +1,12 @@
+package tech.relaycorp.relaynet.messages.payloads
+
+import org.junit.jupiter.api.assertThrows
+import kotlin.test.Test
+
+internal class ServiceMessageTest {
+    @Test
+    fun deserialize() {
+        // TODO
+        assertThrows<NotImplementedError> { ServiceMessage().serialize() }
+    }
+}