Add signature exchange to transaction key flow (#1417)

Require a signature on a deterministic data blob (which includes X.500 name and public key) when exchanging new confidential identities, in order to ensure that the owner of the key pair wants it to represent the specified name, not just that the certificate owner states the key represents the given identity.
This commit is contained in:
Ross Nicoll 2017-10-09 17:03:04 +01:00 committed by GitHub
parent 7340a2e32f
commit 7ad754fe78
5 changed files with 148 additions and 19 deletions

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@ -1,15 +1,32 @@
package net.corda.confidential
import co.paralleluniverse.fibers.Suspendable
import net.corda.core.crypto.DigitalSignature
import net.corda.core.flows.FlowException
import net.corda.core.flows.FlowLogic
import net.corda.core.flows.InitiatingFlow
import net.corda.core.flows.StartableByRPC
import net.corda.core.identity.AnonymousParty
import net.corda.core.identity.CordaX500Name
import net.corda.core.identity.Party
import net.corda.core.identity.PartyAndCertificate
import net.corda.core.internal.toX509CertHolder
import net.corda.core.node.services.IdentityService
import net.corda.core.serialization.CordaSerializable
import net.corda.core.serialization.SerializedBytes
import net.corda.core.serialization.deserialize
import net.corda.core.serialization.serialize
import net.corda.core.utilities.ProgressTracker
import net.corda.core.utilities.unwrap
import org.bouncycastle.asn1.DERSet
import org.bouncycastle.asn1.pkcs.CertificationRequestInfo
import org.bouncycastle.asn1.x509.SubjectPublicKeyInfo
import java.io.ByteArrayOutputStream
import java.nio.charset.Charset
import java.security.PublicKey
import java.security.SignatureException
import java.security.cert.CertPath
import java.util.*
/**
* Very basic flow which generates new confidential identities for parties in a transaction and exchanges the transaction
@ -27,8 +44,32 @@ class SwapIdentitiesFlow(private val otherParty: Party,
object AWAITING_KEY : ProgressTracker.Step("Awaiting key")
fun tracker() = ProgressTracker(AWAITING_KEY)
fun validateAndRegisterIdentity(identityService: IdentityService, otherSide: Party, anonymousOtherSide: PartyAndCertificate): PartyAndCertificate {
require(anonymousOtherSide.name == otherSide.name)
/**
* Generate the determinstic data blob the confidential identity's key holder signs to indicate they want to
* represent the subject named in the X.509 certificate. Note that this is never actually sent between nodes,
* but only the signature is sent. The blob is built independently on each node and the received signature
* verified against the expected blob, rather than exchanging the blob.
*/
fun buildDataToSign(confidentialIdentity: PartyAndCertificate): ByteArray {
val certOwnerAssert = CertificateOwnershipAssertion(confidentialIdentity.name, confidentialIdentity.owningKey)
return certOwnerAssert.serialize().bytes
}
@Throws(SwapIdentitiesException::class)
fun validateAndRegisterIdentity(identityService: IdentityService,
otherSide: Party,
anonymousOtherSideBytes: PartyAndCertificate,
sigBytes: DigitalSignature): PartyAndCertificate {
val anonymousOtherSide: PartyAndCertificate = anonymousOtherSideBytes
if (anonymousOtherSide.name != otherSide.name) {
throw SwapIdentitiesException("Certificate subject must match counterparty's well known identity.")
}
val signature = DigitalSignature.WithKey(anonymousOtherSide.owningKey, sigBytes.bytes)
try {
signature.verify(buildDataToSign(anonymousOtherSideBytes))
} catch(ex: SignatureException) {
throw SwapIdentitiesException("Signature does not match the expected identity ownership assertion.", ex)
}
// Validate then store their identity so that we can prove the key in the transaction is owned by the
// counterparty.
identityService.verifyAndRegisterIdentity(anonymousOtherSide)
@ -40,6 +81,7 @@ class SwapIdentitiesFlow(private val otherParty: Party,
override fun call(): LinkedHashMap<Party, AnonymousParty> {
progressTracker.currentStep = AWAITING_KEY
val legalIdentityAnonymous = serviceHub.keyManagementService.freshKeyAndCert(ourIdentityAndCert, revocationEnabled)
val serializedIdentity = SerializedBytes<PartyAndCertificate>(legalIdentityAnonymous.serialize().bytes)
// Special case that if we're both parties, a single identity is generated
val identities = LinkedHashMap<Party, AnonymousParty>()
@ -47,13 +89,33 @@ class SwapIdentitiesFlow(private val otherParty: Party,
identities.put(otherParty, legalIdentityAnonymous.party.anonymise())
} else {
val otherSession = initiateFlow(otherParty)
val anonymousOtherSide = otherSession.sendAndReceive<PartyAndCertificate>(legalIdentityAnonymous).unwrap { confidentialIdentity ->
validateAndRegisterIdentity(serviceHub.identityService, otherSession.counterparty, confidentialIdentity)
val data = buildDataToSign(legalIdentityAnonymous)
val ourSig: DigitalSignature.WithKey = serviceHub.keyManagementService.sign(data, legalIdentityAnonymous.owningKey)
val ourIdentWithSig = IdentityWithSignature(serializedIdentity, ourSig.withoutKey())
val anonymousOtherSide = otherSession.sendAndReceive<IdentityWithSignature>(ourIdentWithSig)
.unwrap { (confidentialIdentityBytes, theirSigBytes) ->
val confidentialIdentity: PartyAndCertificate = confidentialIdentityBytes.bytes.deserialize()
validateAndRegisterIdentity(serviceHub.identityService, otherParty, confidentialIdentity, theirSigBytes)
}
identities.put(ourIdentity, legalIdentityAnonymous.party.anonymise())
identities.put(otherSession.counterparty, anonymousOtherSide.party.anonymise())
identities.put(otherParty, anonymousOtherSide.party.anonymise())
}
return identities
}
@CordaSerializable
data class IdentityWithSignature(val identity: SerializedBytes<PartyAndCertificate>, val signature: DigitalSignature)
}
/**
* Data class used only in the context of asserting the owner of the private key for the listed key wants to use it
* to represent the named entity. This is pairs with an X.509 certificate (which asserts the signing identity says
* the key represents the named entity), but protects against a certificate authority incorrectly claiming others'
* keys.
*/
@CordaSerializable
data class CertificateOwnershipAssertion(val x500Name: CordaX500Name,
val publicKey: PublicKey)
open class SwapIdentitiesException @JvmOverloads constructor(message: String, cause: Throwable? = null)
: FlowException(message, cause)

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@ -4,6 +4,9 @@ import co.paralleluniverse.fibers.Suspendable
import net.corda.core.flows.FlowLogic
import net.corda.core.flows.FlowSession
import net.corda.core.identity.PartyAndCertificate
import net.corda.core.serialization.SerializedBytes
import net.corda.core.serialization.deserialize
import net.corda.core.serialization.serialize
import net.corda.core.utilities.ProgressTracker
import net.corda.core.utilities.unwrap
@ -20,9 +23,14 @@ class SwapIdentitiesHandler(val otherSideSession: FlowSession, val revocationEna
override fun call() {
val revocationEnabled = false
progressTracker.currentStep = SENDING_KEY
val legalIdentityAnonymous = serviceHub.keyManagementService.freshKeyAndCert(ourIdentityAndCert, revocationEnabled)
otherSideSession.sendAndReceive<PartyAndCertificate>(legalIdentityAnonymous).unwrap { confidentialIdentity ->
SwapIdentitiesFlow.validateAndRegisterIdentity(serviceHub.identityService, otherSideSession.counterparty, confidentialIdentity)
val ourConfidentialIdentity = serviceHub.keyManagementService.freshKeyAndCert(ourIdentityAndCert, revocationEnabled)
val serializedIdentity = SerializedBytes<PartyAndCertificate>(ourConfidentialIdentity.serialize().bytes)
val data = SwapIdentitiesFlow.buildDataToSign(ourConfidentialIdentity)
val ourSig = serviceHub.keyManagementService.sign(data, ourConfidentialIdentity.owningKey)
otherSideSession.sendAndReceive<SwapIdentitiesFlow.IdentityWithSignature>(SwapIdentitiesFlow.IdentityWithSignature(serializedIdentity, ourSig.withoutKey()))
.unwrap { (theirConfidentialIdentityBytes, theirSigBytes) ->
val theirConfidentialIdentity = theirConfidentialIdentityBytes.deserialize()
SwapIdentitiesFlow.validateAndRegisterIdentity(serviceHub.identityService, otherSideSession.counterparty, theirConfidentialIdentity, theirSigBytes)
}
}
}

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@ -4,16 +4,10 @@ import net.corda.core.identity.AbstractParty
import net.corda.core.identity.AnonymousParty
import net.corda.core.identity.Party
import net.corda.core.utilities.getOrThrow
import net.corda.testing.ALICE
import net.corda.testing.BOB
import net.corda.testing.DUMMY_NOTARY
import net.corda.testing.chooseIdentity
import net.corda.testing.*
import net.corda.testing.node.MockNetwork
import org.junit.Test
import kotlin.test.assertEquals
import kotlin.test.assertFalse
import kotlin.test.assertNotEquals
import kotlin.test.assertTrue
import kotlin.test.*
class SwapIdentitiesFlowTests {
@Test
@ -52,4 +46,69 @@ class SwapIdentitiesFlowTests {
mockNet.stopNodes()
}
/**
* Check that flow is actually validating the name on the certificate presented by the counterparty.
*/
@Test
fun `verifies identity name`() {
// We run this in parallel threads to help catch any race conditions that may exist.
val mockNet = MockNetwork(false, true)
// Set up values we'll need
val notaryNode = mockNet.createNotaryNode(DUMMY_NOTARY.name)
val aliceNode = mockNet.createPartyNode(ALICE.name)
val bobNode = mockNet.createPartyNode(BOB.name)
val bob: Party = bobNode.services.myInfo.chooseIdentity()
val notBob = notaryNode.database.transaction {
notaryNode.services.keyManagementService.freshKeyAndCert(notaryNode.services.myInfo.chooseIdentityAndCert(), false)
}
val sigData = SwapIdentitiesFlow.buildDataToSign(notBob)
val signature = notaryNode.services.keyManagementService.sign(sigData, notBob.owningKey)
assertFailsWith<SwapIdentitiesException>("Certificate subject must match counterparty's well known identity.") {
SwapIdentitiesFlow.validateAndRegisterIdentity(aliceNode.services.identityService, bob, notBob, signature.withoutKey())
}
mockNet.stopNodes()
}
/**
* Check that flow is actually validating its the signature presented by the counterparty.
*/
@Test
fun `verifies signature`() {
// We run this in parallel threads to help catch any race conditions that may exist.
val mockNet = MockNetwork(false, true)
// Set up values we'll need
val notaryNode = mockNet.createNotaryNode(DUMMY_NOTARY.name)
val aliceNode = mockNet.createPartyNode(ALICE.name)
val bobNode = mockNet.createPartyNode(BOB.name)
val bob: Party = bobNode.services.myInfo.chooseIdentity()
// Check that the wrong signature is rejected
notaryNode.database.transaction {
notaryNode.services.keyManagementService.freshKeyAndCert(notaryNode.services.myInfo.chooseIdentityAndCert(), false)
}.let { anonymousNotary ->
val sigData = SwapIdentitiesFlow.buildDataToSign(anonymousNotary)
val signature = notaryNode.services.keyManagementService.sign(sigData, anonymousNotary.owningKey)
assertFailsWith<SwapIdentitiesException>("Signature does not match the given identity and nonce") {
SwapIdentitiesFlow.validateAndRegisterIdentity(aliceNode.services.identityService, bob, anonymousNotary, signature.withoutKey())
}
}
// Check that the right signing key, but wrong identity is rejected
val anonymousAlice = aliceNode.database.transaction {
aliceNode.services.keyManagementService.freshKeyAndCert(aliceNode.services.myInfo.chooseIdentityAndCert(), false)
}
bobNode.database.transaction {
bobNode.services.keyManagementService.freshKeyAndCert(bobNode.services.myInfo.chooseIdentityAndCert(), false)
}.let { anonymousBob ->
val sigData = SwapIdentitiesFlow.buildDataToSign(anonymousAlice)
val signature = bobNode.services.keyManagementService.sign(sigData, anonymousBob.owningKey)
assertFailsWith<SwapIdentitiesException>("Signature does not match the given identity and nonce.") {
SwapIdentitiesFlow.validateAndRegisterIdentity(aliceNode.services.identityService, bob, anonymousBob, signature.withoutKey())
}
}
mockNet.stopNodes()
}
}

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@ -46,5 +46,6 @@ open class DigitalSignature(bytes: ByteArray) : OpaqueBytes(bytes) {
*/
@Throws(InvalidKeyException::class, SignatureException::class)
fun isValid(content: ByteArray) = by.isValid(content, this)
fun withoutKey() : DigitalSignature = DigitalSignature(this.bytes)
}
}

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@ -196,7 +196,6 @@ fun <T : Any> T.serialize(serializationFactory: SerializationFactory = Serializa
* A type safe wrapper around a byte array that contains a serialised object. You can call [SerializedBytes.deserialize]
* to get the original object back.
*/
@Suppress("unused") // Type parameter is just for documentation purposes.
class SerializedBytes<T : Any>(bytes: ByteArray) : OpaqueBytes(bytes) {
// It's OK to use lazy here because SerializedBytes is configured to use the ImmutableClassSerializer.
val hash: SecureHash by lazy { bytes.sha256() }