Add certificate path storage to identity service

Add functionality for generating certificate paths from identity
certificates to transaction certificates, validating, storing and
retrieving those certificate paths.

core/src/main/kotlin/net/corda/core/crypto/CompositeSignature.kt

@@ -1,6 +1,8 @@
 package net.corda.core.crypto
 
 import net.corda.core.serialization.deserialize
+import org.bouncycastle.asn1.ASN1ObjectIdentifier
+import org.bouncycastle.asn1.x509.AlgorithmIdentifier
 import java.io.ByteArrayOutputStream
 import java.security.*
 import java.security.spec.AlgorithmParameterSpec
@@ -10,7 +12,12 @@ import java.security.spec.AlgorithmParameterSpec
  */
 class CompositeSignature : Signature(ALGORITHM) {
     companion object {
-        val ALGORITHM = "X-Corda-CompositeSig"
+        val ALGORITHM = "2.25.30086077608615255153862931087626791003"
+        // UUID-based OID
+        // TODO: Register for an OID space and issue our own shorter OID
+        val ALGORITHM_IDENTIFIER = AlgorithmIdentifier(ASN1ObjectIdentifier(ALGORITHM))
+
+        fun getService(provider: Provider) = Provider.Service(provider, "Signature", ALGORITHM, CompositeSignature::class.java.name, emptyList(), emptyMap())
     }
 
     private var signatureState: State? = null

core/src/main/kotlin/net/corda/core/crypto/X509Utilities.kt

@@ -17,11 +17,11 @@ import java.io.FileWriter
 import java.io.InputStream
 import java.net.InetAddress
 import java.nio.file.Path
+import java.security.InvalidAlgorithmParameterException
 import java.security.KeyPair
 import java.security.KeyStore
 import java.security.PublicKey
-import java.security.cert.CertificateFactory
+import java.security.cert.*
-import java.security.cert.X509Certificate
 import java.time.Instant
 import java.time.temporal.ChronoUnit
 import java.util.*
@@ -64,7 +64,7 @@ object X509Utilities {
     }
 
     /**
-     * Return a bogus X509 for dev purposes.
+     * Return a bogus X509 for dev purposes. Use [getX509Name] for something more real.
      */
     @Deprecated("Full legal names should be specified in all configurations")
     fun getDevX509Name(commonName: String): X500Name {
@@ -160,6 +160,34 @@ object X509Utilities {
         return Crypto.createCertificate(issuer, ca.keyPair, subject, publicKey, CLIENT_KEY_USAGE, CLIENT_KEY_PURPOSES, window, subjectAlternativeName = dnsNames + ipAddresses)
     }
 
+    /**
+     * Build a certificate path from a trusted root certificate to a target certificate. This will always return a path
+     * directly from the root to the target, with no intermediate certificates (presuming that path is valid).
+     *
+     * @param rootCertAndKey trusted root certificate that will be the start of the path.
+     * @param targetCertAndKey certificate the path ends at.
+     * @param revocationEnabled whether revocation of certificates in the path should be checked.
+     */
+    fun createCertificatePath(rootCertAndKey: CertificateAndKey,
+                              targetCertAndKey: CertificateAndKey,
+                              revocationEnabled: Boolean): CertPathBuilderResult {
+        val intermediateCertificates = setOf(targetCertAndKey.certificate)
+        val certStore = CertStore.getInstance("Collection", CollectionCertStoreParameters(intermediateCertificates))
+        val certPathFactory = CertPathBuilder.getInstance("PKIX")
+        val trustAnchor = TrustAnchor(rootCertAndKey.certificate, null)
+        val certPathParameters = try {
+            PKIXBuilderParameters(setOf(trustAnchor), X509CertSelector().apply {
+                certificate = targetCertAndKey.certificate
+            })
+        } catch (ex: InvalidAlgorithmParameterException) {
+            throw RuntimeException(ex)
+        }.apply {
+            addCertStore(certStore)
+            isRevocationEnabled = revocationEnabled
+        }
+        return certPathFactory.build(certPathParameters)
+    }
+
     /**
      * Helper method to store a .pem/.cer format file copy of a certificate if required for import into a PC/Mac, or for inspection
      * @param x509Certificate certificate to save

core/src/main/kotlin/net/corda/core/identity/Party.kt

@@ -1,6 +1,7 @@
 package net.corda.core.identity
 
 import net.corda.core.contracts.PartyAndReference
+import net.corda.core.crypto.CertificateAndKey
 import net.corda.core.crypto.toBase58String
 import net.corda.core.serialization.OpaqueBytes
 import org.bouncycastle.asn1.x500.X500Name
@@ -27,6 +28,7 @@ import java.security.PublicKey
  */
 // TODO: Remove "open" from [Party] once deprecated crypto.Party class is removed
 open class Party(val name: X500Name, owningKey: PublicKey) : AbstractParty(owningKey) {
+    constructor(certAndKey: CertificateAndKey) : this(X500Name(certAndKey.certificate.subjectDN.name), certAndKey.keyPair.public)
     override fun toAnonymous(): AnonymousParty = AnonymousParty(owningKey)
     override fun toString() = "${owningKey.toBase58String()} ($name)"
     override fun nameOrNull(): X500Name? = name

core/src/main/kotlin/net/corda/core/node/services/IdentityService.kt

@@ -5,6 +5,8 @@ import net.corda.core.identity.AnonymousParty
 import net.corda.core.identity.Party
 import org.bouncycastle.asn1.x500.X500Name
 import java.security.PublicKey
+import java.security.cert.CertPath
+import java.security.cert.X509Certificate
 
 /**
  * An identity service maintains an bidirectional map of [Party]s to their associated public keys and thus supports
@@ -14,6 +16,29 @@ import java.security.PublicKey
 interface IdentityService {
     fun registerIdentity(party: Party)
 
+    /**
+     * Verify and then store the certificates proving that an anonymous party's key is owned by the given full
+     * party.
+     *
+     * @param trustedRoot trusted root certificate, typically the R3 master signing certificate.
+     * @param anonymousParty an anonymised party belonging to the legal entity.
+     * @param path certificate path from the trusted root to the anonymised party.
+     * @throws IllegalArgumentException if the chain does not link the two parties, or if there is already an existing
+     * certificate chain for the anonymous party. Anonymous parties must always resolve to a single owning party.
+     */
+    // TODO: Move this into internal identity service once available
+    @Throws(IllegalArgumentException::class)
+    fun registerPath(trustedRoot: X509Certificate, anonymousParty: AnonymousParty, path: CertPath)
+
+    /**
+     * Asserts that an anonymous party maps to the given full party, by looking up the certificate chain associated with
+     * the anonymous party and resolving it back to the given full party.
+     *
+     * @throws IllegalStateException if the anonymous party is not owned by the full party.
+     */
+    @Throws(IllegalStateException::class)
+    fun assertOwnership(party: Party, anonymousParty: AnonymousParty)
+
     /**
      * Get all identities known to the service. This is expensive, and [partyFromKey] or [partyFromX500Name] should be
      * used in preference where possible.
@@ -31,4 +56,11 @@ interface IdentityService {
 
     fun partyFromAnonymous(party: AnonymousParty): Party?
     fun partyFromAnonymous(partyRef: PartyAndReference) = partyFromAnonymous(partyRef.party)
+
+    /**
+     * Get the certificate chain showing an anonymous party is owned by the given party.
+     */
+    fun pathForAnonymous(anonymousParty: AnonymousParty): CertPath?
+
+    class UnknownAnonymousPartyException(msg: String) : Exception(msg)
 }

node/src/main/kotlin/net/corda/node/services/identity/InMemoryIdentityService.kt

@@ -1,6 +1,8 @@
 package net.corda.node.services.identity
 
 import net.corda.core.contracts.PartyAndReference
+import net.corda.core.contracts.requireThat
+import net.corda.core.crypto.toStringShort
 import net.corda.core.identity.AnonymousParty
 import net.corda.core.identity.Party
 import net.corda.core.node.services.IdentityService
@@ -8,10 +10,13 @@ import net.corda.core.serialization.SingletonSerializeAsToken
 import net.corda.core.utilities.loggerFor
 import net.corda.core.utilities.trace
 import org.bouncycastle.asn1.x500.X500Name
+import java.security.InvalidAlgorithmParameterException
 import java.security.PublicKey
+import java.security.cert.*
 import java.util.*
 import java.util.concurrent.ConcurrentHashMap
 import javax.annotation.concurrent.ThreadSafe
+import javax.security.auth.x500.X500Principal
 
 /**
  * Simple identity service which caches parties and provides functionality for efficient lookup.
@@ -24,6 +29,7 @@ class InMemoryIdentityService : SingletonSerializeAsToken(), IdentityService {
 
     private val keyToParties = ConcurrentHashMap<PublicKey, Party>()
     private val principalToParties = ConcurrentHashMap<X500Name, Party>()
+    private val partyToPath = ConcurrentHashMap<AnonymousParty, CertPath>()
 
     override fun registerIdentity(party: Party) {
         log.trace { "Registering identity $party" }
@@ -40,4 +46,36 @@ class InMemoryIdentityService : SingletonSerializeAsToken(), IdentityService {
     override fun partyFromX500Name(principal: X500Name): Party? = principalToParties[principal]
     override fun partyFromAnonymous(party: AnonymousParty): Party? = partyFromKey(party.owningKey)
     override fun partyFromAnonymous(partyRef: PartyAndReference) = partyFromAnonymous(partyRef.party)
+
+    @Throws(IdentityService.UnknownAnonymousPartyException::class)
+    override fun assertOwnership(party: Party, anonymousParty: AnonymousParty) {
+        val path = partyToPath[anonymousParty] ?: throw IdentityService.UnknownAnonymousPartyException("Unknown anonymous party ${anonymousParty.owningKey.toStringShort()}")
+        val target = path.certificates.last() as X509Certificate
+        requireThat {
+            "Certificate path ends with \"${target.issuerX500Principal}\" expected \"${party.name}\"" using (X500Name(target.subjectX500Principal.name) == party.name)
+            "Certificate path ends with correct public key" using (target.publicKey == anonymousParty.owningKey)
+        }
+        // Verify there's a previous certificate in the path, which matches
+        val root = path.certificates.first() as X509Certificate
+        require(X500Name(root.issuerX500Principal.name) == party.name) { "Certificate path starts with \"${root.issuerX500Principal}\" expected \"${party.name}\"" }
+    }
+
+    override fun pathForAnonymous(anonymousParty: AnonymousParty): CertPath? = partyToPath[anonymousParty]
+
+    @Throws(CertificateExpiredException::class, CertificateNotYetValidException::class, InvalidAlgorithmParameterException::class)
+    override fun registerPath(trustedRoot: X509Certificate, anonymousParty: AnonymousParty, path: CertPath) {
+        val expectedTrustAnchor = TrustAnchor(trustedRoot, null)
+        require(path.certificates.isNotEmpty()) { "Certificate path must contain at least one certificate" }
+        val target = path.certificates.last() as X509Certificate
+        require(target.publicKey == anonymousParty.owningKey) { "Certificate path must end with anonymous party's public key" }
+        val validator = CertPathValidator.getInstance("PKIX")
+        val validatorParameters = PKIXParameters(setOf(expectedTrustAnchor)).apply {
+            isRevocationEnabled = false
+        }
+        val result = validator.validate(path, validatorParameters) as PKIXCertPathValidatorResult
+        require(result.trustAnchor == expectedTrustAnchor)
+        require(result.publicKey == anonymousParty.owningKey)
+
+        partyToPath[anonymousParty] = path
+    }
 }

node/src/test/kotlin/net/corda/node/services/network/InMemoryIdentityServiceTests.kt

@@ -1,23 +1,26 @@
 package net.corda.node.services.network
 
-import net.corda.core.identity.Party
+import net.corda.core.crypto.CertificateAndKey
 import net.corda.core.crypto.X509Utilities
 import net.corda.core.crypto.generateKeyPair
-import net.corda.node.services.identity.InMemoryIdentityService
+import net.corda.core.identity.AnonymousParty
+import net.corda.core.identity.Party
+import net.corda.core.node.services.IdentityService
 import net.corda.core.utilities.ALICE
 import net.corda.core.utilities.BOB
+import net.corda.node.services.identity.InMemoryIdentityService
 import net.corda.testing.ALICE_PUBKEY
 import net.corda.testing.BOB_PUBKEY
 import org.bouncycastle.asn1.x500.X500Name
 import org.junit.Test
 import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
 import kotlin.test.assertNull
 
 /**
  * Tests for the in memory identity service.
  */
 class InMemoryIdentityServiceTests {
-
     @Test
     fun `get all identities`() {
         val service = InMemoryIdentityService()
@@ -58,4 +61,54 @@ class InMemoryIdentityServiceTests {
         identities.forEach { service.registerIdentity(it) }
         identities.forEach { assertEquals(it, service.partyFromX500Name(it.name)) }
     }
+
+    /**
+     * Generate a certificate path from a root CA, down to a transaction key, store and verify the association.
+     */
+    @Test
+    fun `assert unknown anonymous key is unrecognised`() {
+        val rootCertAndKey = X509Utilities.createSelfSignedCACert(ALICE.name)
+        val txCertAndKey = X509Utilities.createIntermediateCert(ALICE.name, rootCertAndKey)
+        val service = InMemoryIdentityService()
+        val rootKey = rootCertAndKey.keyPair
+        // TODO: Generate certificate with an EdDSA key rather than ECDSA
+        val identity = Party(rootCertAndKey)
+        val txIdentity = AnonymousParty(txCertAndKey.keyPair.public)
+
+        assertFailsWith<IdentityService.UnknownAnonymousPartyException> {
+            service.assertOwnership(identity, txIdentity)
+        }
+    }
+
+    /**
+     * Generate a pair of certificate paths from a root CA, down to a transaction key, store and verify the associations.
+     * Also checks that incorrect associations are rejected.
+     */
+    @Test
+    fun `assert ownership`() {
+        val aliceRootCertAndKey = X509Utilities.createSelfSignedCACert(ALICE.name)
+        val aliceTxCertAndKey = X509Utilities.createIntermediateCert(ALICE.name, aliceRootCertAndKey)
+        val aliceCertPath = X509Utilities.createCertificatePath(aliceRootCertAndKey, aliceTxCertAndKey, false).certPath
+        val bobRootCertAndKey = X509Utilities.createSelfSignedCACert(BOB.name)
+        val bobTxCertAndKey = X509Utilities.createIntermediateCert(BOB.name, bobRootCertAndKey)
+        val bobCertPath = X509Utilities.createCertificatePath(bobRootCertAndKey, bobTxCertAndKey, false).certPath
+        val service = InMemoryIdentityService()
+        val alice = Party(aliceRootCertAndKey)
+        val anonymousAlice = AnonymousParty(aliceTxCertAndKey.keyPair.public)
+        val bob = Party(bobRootCertAndKey)
+        val anonymousBob = AnonymousParty(bobTxCertAndKey.keyPair.public)
+
+        service.registerPath(aliceRootCertAndKey.certificate, anonymousAlice, aliceCertPath)
+        service.registerPath(bobRootCertAndKey.certificate, anonymousBob, bobCertPath)
+
+        // Verify that paths are verified
+        service.assertOwnership(alice, anonymousAlice)
+        service.assertOwnership(bob, anonymousBob)
+        assertFailsWith<IllegalArgumentException> {
+            service.assertOwnership(alice, anonymousBob)
+        }
+        assertFailsWith<IllegalArgumentException> {
+            service.assertOwnership(bob, anonymousAlice)
+        }
+    }
 }

test-utils/src/main/kotlin/net/corda/testing/node/MockServices.kt

@@ -28,10 +28,13 @@ import java.io.ByteArrayInputStream
 import java.io.ByteArrayOutputStream
 import java.io.File
 import java.io.InputStream
+import java.nio.file.Path
 import java.nio.file.Paths
 import java.security.KeyPair
 import java.security.PrivateKey
 import java.security.PublicKey
+import java.security.cert.CertPath
+import java.security.cert.X509Certificate
 import java.time.Clock
 import java.util.*
 import java.util.jar.JarInputStream
@@ -73,11 +76,14 @@ open class MockServices(val key: KeyPair = generateKeyPair()) : ServiceHub {
 }
 
 @ThreadSafe
-class MockIdentityService(val identities: List<Party>) : IdentityService, SingletonSerializeAsToken() {
+class MockIdentityService(val identities: List<Party>,
+                          val certificates: List<Triple<AnonymousParty, Party, CertPath>> = emptyList()) : IdentityService, SingletonSerializeAsToken() {
     private val keyToParties: Map<PublicKey, Party>
         get() = synchronized(identities) { identities.associateBy { it.owningKey } }
     private val nameToParties: Map<X500Name, Party>
         get() = synchronized(identities) { identities.associateBy { it.name } }
+    private val anonymousToPath: Map<AnonymousParty, Pair<Party, CertPath>>
+        get() = synchronized(certificates) { certificates.map { Pair(it.first, Pair(it.second, it.third)) }.toMap() }
 
     override fun registerIdentity(party: Party) {
         throw UnsupportedOperationException()
@@ -89,6 +95,13 @@ class MockIdentityService(val identities: List<Party>) : IdentityService, Single
     override fun partyFromKey(key: PublicKey): Party? = keyToParties[key]
     override fun partyFromName(name: String): Party? = nameToParties[X500Name(name)]
     override fun partyFromX500Name(principal: X500Name): Party? = nameToParties[principal]
+
+    @Throws(IllegalStateException::class)
+    override fun assertOwnership(party: Party, anonymousParty: AnonymousParty) {
+        check(anonymousToPath[anonymousParty]?.first == party)
+    }
+    override fun pathForAnonymous(anonymousParty: AnonymousParty): CertPath? = anonymousToPath[anonymousParty]?.second
+    override fun registerPath(trustedRoot: X509Certificate, anonymousParty: AnonymousParty, path: CertPath) { throw UnsupportedOperationException() }
 }