feat: Implement nonce signature (#80)

relaycorp · Aug 11, 2020 · aae0c50 · aae0c50
1 parent 8fc146e
commit aae0c50
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Showing 12 changed files with 356 additions and 68 deletions.
diff --git a/src/main/kotlin/tech/relaycorp/relaynet/OIDs.kt b/src/main/kotlin/tech/relaycorp/relaynet/OIDs.kt
@@ -12,4 +12,6 @@ internal object OIDs {
         CLIENT_REGISTRATION_PREFIX.branch("0").intern()
     val CRA_COUNTERSIGNATURE: ASN1ObjectIdentifier =
         CLIENT_REGISTRATION_PREFIX.branch("1").intern()
+
+    val NONCE_SIGNATURE: ASN1ObjectIdentifier = RELAYNET.branch("3").intern()
 }
diff --git a/src/main/kotlin/tech/relaycorp/relaynet/crypto/SignedData.kt b/src/main/kotlin/tech/relaycorp/relaynet/crypto/SignedData.kt
@@ -29,7 +29,7 @@ import java.security.PublicKey
 /**
  * Relaynet-specific, CMS SignedData representation.
  */
-class SignedData(internal val bcSignedData: CMSSignedData) {
+internal class SignedData(internal val bcSignedData: CMSSignedData) {
     /**
      * The signed plaintext, if it was encapsulated.
      */

diff --git a/src/main/kotlin/tech/relaycorp/relaynet/messages/control/NonceSignature.kt b/src/main/kotlin/tech/relaycorp/relaynet/messages/control/NonceSignature.kt
@@ -0,0 +1,64 @@
+package tech.relaycorp.relaynet.messages.control
+
+import org.bouncycastle.asn1.ASN1TaggedObject
+import org.bouncycastle.asn1.DEROctetString
+import tech.relaycorp.relaynet.OIDs
+import tech.relaycorp.relaynet.crypto.SignedData
+import tech.relaycorp.relaynet.crypto.SignedDataException
+import tech.relaycorp.relaynet.messages.InvalidMessageException
+import tech.relaycorp.relaynet.wrappers.asn1.ASN1Exception
+import tech.relaycorp.relaynet.wrappers.asn1.ASN1Utils
+import tech.relaycorp.relaynet.wrappers.x509.Certificate
+import java.security.PrivateKey
+
+/**
+ * Nonce signature.
+ */
+class NonceSignature(val nonce: ByteArray, val signerCertificate: Certificate) {
+    /**
+     * Serialize signature.
+     */
+    fun serialize(privateKey: PrivateKey): ByteArray {
+        val plaintext = ASN1Utils.serializeSequence(
+            arrayOf(OIDs.NONCE_SIGNATURE, DEROctetString(nonce)),
+            false
+        )
+        val signedData = SignedData.sign(
+            plaintext,
+            privateKey,
+            signerCertificate,
+            encapsulatedCertificates = setOf(signerCertificate)
+        )
+        return signedData.serialize()
+    }
+
+    companion object {
+        /**
+         * Deserialize and validate nonce signature.
+         */
+        @Throws(InvalidMessageException::class)
+        fun deserialize(serialization: ByteArray): NonceSignature {
+            val signedData = try {
+                SignedData.deserialize(serialization).also { it.verify() }
+            } catch (exc: SignedDataException) {
+                throw InvalidMessageException("SignedData value is invalid", exc)
+            }
+            val sequence = try {
+                ASN1Utils.deserializeSequence(signedData.plaintext!!)
+            } catch (exc: ASN1Exception) {
+                throw InvalidMessageException("Signature plaintext is not a DER sequence", exc)
+            }
+            if (sequence.size < 2) {
+                throw InvalidMessageException(
+                    "Signature sequence should have at least 2 items (got ${sequence.size})"
+                )
+            }
+            val oid = ASN1Utils.deserializeOID(sequence.first() as ASN1TaggedObject)
+            if (oid != OIDs.NONCE_SIGNATURE) {
+                throw InvalidMessageException("Signature OID is invalid (got ${oid.id})")
+            }
+            val nonce = DEROctetString.getInstance(sequence[1] as ASN1TaggedObject, false)
+            return NonceSignature(nonce.octets, signedData.signerCertificate!!)
+        }
+    }
+}
diff --git a/src/main/kotlin/tech/relaycorp/relaynet/wrappers/asn1/ASN1Exception.kt b/src/main/kotlin/tech/relaycorp/relaynet/wrappers/asn1/ASN1Exception.kt
@@ -1,3 +1,3 @@
 package tech.relaycorp.relaynet.wrappers.asn1
 
-class ASN1Exception(message: String) : Exception(message)
+class ASN1Exception(message: String, cause: Throwable? = null) : Exception(message, cause)
diff --git a/src/main/kotlin/tech/relaycorp/relaynet/wrappers/asn1/ASN1Utils.kt b/src/main/kotlin/tech/relaycorp/relaynet/wrappers/asn1/ASN1Utils.kt
@@ -3,7 +3,9 @@ package tech.relaycorp.relaynet.wrappers.asn1
 import org.bouncycastle.asn1.ASN1Encodable
 import org.bouncycastle.asn1.ASN1EncodableVector
 import org.bouncycastle.asn1.ASN1InputStream
+import org.bouncycastle.asn1.ASN1ObjectIdentifier
 import org.bouncycastle.asn1.ASN1Sequence
+import org.bouncycastle.asn1.ASN1TaggedObject
 import org.bouncycastle.asn1.DERGeneralizedTime
 import org.bouncycastle.asn1.DERSequence
 import org.bouncycastle.asn1.DERTaggedObject
@@ -49,4 +51,16 @@ internal object ASN1Utils {
         val dateUTC = date.withZoneSameInstant(ZoneOffset.UTC)
         return DERGeneralizedTime(dateUTC.format(BER_DATETIME_FORMATTER))
     }
+
+    @Throws(ASN1Exception::class)
+    fun deserializeOID(
+        oidSerialized: ASN1TaggedObject,
+        explicitTagging: Boolean = false
+    ): ASN1ObjectIdentifier {
+        return try {
+            ASN1ObjectIdentifier.getInstance(oidSerialized, explicitTagging)
+        } catch (exc: IllegalArgumentException) {
+            throw ASN1Exception("Value is not an OID", exc)
+        }
+    }
 }
diff --git a/src/test/kotlin/tech/relaycorp/relaynet/DummyCertPath.kt b/src/test/kotlin/tech/relaycorp/relaynet/DummyCertPath.kt
diff --git a/src/test/kotlin/tech/relaycorp/relaynet/FullCertPath.kt b/src/test/kotlin/tech/relaycorp/relaynet/FullCertPath.kt
@@ -0,0 +1,31 @@
+package tech.relaycorp.relaynet
+
+import java.time.ZonedDateTime
+
+object FullCertPath {
+    private val tomorrow = ZonedDateTime.now().plusDays(1)
+
+    val PUBLIC_GW = issueGatewayCertificate(
+        KeyPairSet.PUBLIC_GW.public,
+        KeyPairSet.PUBLIC_GW.private,
+        tomorrow
+    )
+    val PRIVATE_GW = issueGatewayCertificate(
+        KeyPairSet.PRIVATE_GW.public,
+        KeyPairSet.PUBLIC_GW.private,
+        tomorrow,
+        PUBLIC_GW
+    )
+    val PRIVATE_ENDPOINT = issueEndpointCertificate(
+        KeyPairSet.PRIVATE_ENDPOINT.public,
+        KeyPairSet.PRIVATE_GW.private,
+        tomorrow,
+        PRIVATE_GW
+    )
+    val PDA = issueParcelDeliveryAuthorization(
+        KeyPairSet.PDA_GRANTEE.public,
+        KeyPairSet.PRIVATE_ENDPOINT.private,
+        tomorrow,
+        PRIVATE_ENDPOINT
+    )
+}
diff --git a/src/test/kotlin/tech/relaycorp/relaynet/KeyPairSet.kt b/src/test/kotlin/tech/relaycorp/relaynet/KeyPairSet.kt
@@ -0,0 +1,10 @@
+package tech.relaycorp.relaynet
+
+import tech.relaycorp.relaynet.wrappers.generateRSAKeyPair
+
+object KeyPairSet {
+    val PUBLIC_GW = generateRSAKeyPair()
+    val PRIVATE_GW = generateRSAKeyPair()
+    val PRIVATE_ENDPOINT = generateRSAKeyPair()
+    val PDA_GRANTEE = generateRSAKeyPair()
+}
diff --git a/src/test/kotlin/tech/relaycorp/relaynet/messages/control/ClientRegistrationTest.kt b/src/test/kotlin/tech/relaycorp/relaynet/messages/control/ClientRegistrationTest.kt
@@ -5,7 +5,7 @@ import org.bouncycastle.asn1.DERNull
 import org.bouncycastle.asn1.DEROctetString
 import org.junit.jupiter.api.Nested
 import org.junit.jupiter.api.assertThrows
-import tech.relaycorp.relaynet.DummyCertPath
+import tech.relaycorp.relaynet.FullCertPath
 import tech.relaycorp.relaynet.messages.InvalidMessageException
 import tech.relaycorp.relaynet.wrappers.asn1.ASN1Exception
 import tech.relaycorp.relaynet.wrappers.asn1.ASN1Utils
@@ -20,31 +20,31 @@ class ClientRegistrationTest {
         @Test
         fun `Client certificate should be serialized`() {
             val registration =
-                ClientRegistration(DummyCertPath.endpointCert, DummyCertPath.privateGatewayCert)
+                ClientRegistration(FullCertPath.PRIVATE_ENDPOINT, FullCertPath.PRIVATE_GW)
 
             val serialization = registration.serialize()
 
             val sequence = ASN1Utils.deserializeSequence(serialization)
             val clientCertificateASN1 =
                 DEROctetString.getInstance(sequence.first() as ASN1TaggedObject, false)
             assertEquals(
-                DummyCertPath.endpointCert.serialize().asList(),
+                FullCertPath.PRIVATE_ENDPOINT.serialize().asList(),
                 clientCertificateASN1.octets.asList()
             )
         }
 
         @Test
         fun `Server certificate should be serialized`() {
             val registration =
-                ClientRegistration(DummyCertPath.endpointCert, DummyCertPath.privateGatewayCert)
+                ClientRegistration(FullCertPath.PRIVATE_ENDPOINT, FullCertPath.PRIVATE_GW)
 
             val serialization = registration.serialize()
 
             val sequence = ASN1Utils.deserializeSequence(serialization)
             val serverCertificateASN1 =
                 DEROctetString.getInstance(sequence[1] as ASN1TaggedObject, false)
             assertEquals(
-                DummyCertPath.privateGatewayCert.serialize().asList(),
+                FullCertPath.PRIVATE_GW.serialize().asList(),
                 serverCertificateASN1.octets.asList()
             )
         }
@@ -99,7 +99,7 @@ class ClientRegistrationTest {
         fun `Invalid server certificates should be refused`() {
             val invalidSerialization = ASN1Utils.serializeSequence(
                 arrayOf(
-                    DEROctetString(DummyCertPath.endpointCert.serialize()),
+                    DEROctetString(FullCertPath.PRIVATE_ENDPOINT.serialize()),
                     DERNull.INSTANCE
                 ), false
             )
@@ -118,14 +118,14 @@ class ClientRegistrationTest {
         @Test
         fun `Valid registration should be accepted`() {
             val registration =
-                ClientRegistration(DummyCertPath.endpointCert, DummyCertPath.privateGatewayCert)
+                ClientRegistration(FullCertPath.PRIVATE_ENDPOINT, FullCertPath.PRIVATE_GW)
             val serialization = registration.serialize()
 
             val registrationDeserialized = ClientRegistration.deserialize(serialization)
 
-            assertEquals(DummyCertPath.endpointCert, registrationDeserialized.clientCertificate)
+            assertEquals(FullCertPath.PRIVATE_ENDPOINT, registrationDeserialized.clientCertificate)
             assertEquals(
-                DummyCertPath.privateGatewayCert,
+                FullCertPath.PRIVATE_GW,
                 registrationDeserialized.serverCertificate
             )
         }