Expose certificate request type in SslServerCredentials.

src/csharp/Grpc.Core/Internal/NativeMethods.Generated.cs

@@ -505,7 +505,7 @@ namespace Grpc.Core.Internal
             public delegate void grpcsharp_redirect_log_delegate(GprLogDelegate callback);
             public delegate CallCredentialsSafeHandle grpcsharp_metadata_credentials_create_from_plugin_delegate(NativeMetadataInterceptor interceptor);
             public delegate void grpcsharp_metadata_credentials_notify_from_plugin_delegate(IntPtr callbackPtr, IntPtr userData, MetadataArraySafeHandle metadataArray, StatusCode statusCode, string errorDetails);
-            public delegate ServerCredentialsSafeHandle grpcsharp_ssl_server_credentials_create_delegate(string pemRootCerts, string[] keyCertPairCertChainArray, string[] keyCertPairPrivateKeyArray, UIntPtr numKeyCertPairs, int forceClientAuth);
+            public delegate ServerCredentialsSafeHandle grpcsharp_ssl_server_credentials_create_delegate(string pemRootCerts, string[] keyCertPairCertChainArray, string[] keyCertPairPrivateKeyArray, UIntPtr numKeyCertPairs, SslClientCertificateRequestType clientCertificateRequest);
             public delegate void grpcsharp_server_credentials_release_delegate(IntPtr credentials);
             public delegate ServerSafeHandle grpcsharp_server_create_delegate(ChannelArgsSafeHandle args);
             public delegate void grpcsharp_server_register_completion_queue_delegate(ServerSafeHandle server, CompletionQueueSafeHandle cq);
@@ -752,7 +752,7 @@ namespace Grpc.Core.Internal
             public static extern void grpcsharp_metadata_credentials_notify_from_plugin(IntPtr callbackPtr, IntPtr userData, MetadataArraySafeHandle metadataArray, StatusCode statusCode, string errorDetails);
             
             [DllImport(ImportName)]
-            public static extern ServerCredentialsSafeHandle grpcsharp_ssl_server_credentials_create(string pemRootCerts, string[] keyCertPairCertChainArray, string[] keyCertPairPrivateKeyArray, UIntPtr numKeyCertPairs, int forceClientAuth);
+            public static extern ServerCredentialsSafeHandle grpcsharp_ssl_server_credentials_create(string pemRootCerts, string[] keyCertPairCertChainArray, string[] keyCertPairPrivateKeyArray, UIntPtr numKeyCertPairs, SslClientCertificateRequestType clientCertificateRequest);
             
             [DllImport(ImportName)]
             public static extern void grpcsharp_server_credentials_release(IntPtr credentials);
@@ -1045,7 +1045,7 @@ namespace Grpc.Core.Internal
             public static extern void grpcsharp_metadata_credentials_notify_from_plugin(IntPtr callbackPtr, IntPtr userData, MetadataArraySafeHandle metadataArray, StatusCode statusCode, string errorDetails);
             
             [DllImport(ImportName)]
-            public static extern ServerCredentialsSafeHandle grpcsharp_ssl_server_credentials_create(string pemRootCerts, string[] keyCertPairCertChainArray, string[] keyCertPairPrivateKeyArray, UIntPtr numKeyCertPairs, int forceClientAuth);
+            public static extern ServerCredentialsSafeHandle grpcsharp_ssl_server_credentials_create(string pemRootCerts, string[] keyCertPairCertChainArray, string[] keyCertPairPrivateKeyArray, UIntPtr numKeyCertPairs, SslClientCertificateRequestType clientCertificateRequest);
             
             [DllImport(ImportName)]
             public static extern void grpcsharp_server_credentials_release(IntPtr credentials);

src/csharp/Grpc.Core/Internal/ServerCredentialsSafeHandle.cs

@@ -32,13 +32,13 @@ namespace Grpc.Core.Internal
         {
         }
 
-        public static ServerCredentialsSafeHandle CreateSslCredentials(string pemRootCerts, string[] keyCertPairCertChainArray, string[] keyCertPairPrivateKeyArray, bool forceClientAuth)
+        public static ServerCredentialsSafeHandle CreateSslCredentials(string pemRootCerts, string[] keyCertPairCertChainArray, string[] keyCertPairPrivateKeyArray, SslClientCertificateRequestType clientCertificateRequest)
         {
             GrpcPreconditions.CheckArgument(keyCertPairCertChainArray.Length == keyCertPairPrivateKeyArray.Length);
             return Native.grpcsharp_ssl_server_credentials_create(pemRootCerts,
                                                                   keyCertPairCertChainArray, keyCertPairPrivateKeyArray,
                                                                   new UIntPtr((ulong)keyCertPairCertChainArray.Length),
-                                                                  forceClientAuth ? 1 : 0);
+                                                                  clientCertificateRequest);
         }
 
         protected override bool ReleaseHandle()

src/csharp/Grpc.Core/ServerCredentials.cs

@@ -57,6 +57,60 @@ namespace Grpc.Core
         }
     }
 
+    /// <summary>
+    /// Modes of requesting client's SSL certificate by the server.
+    /// Corresponds to <c>grpc_ssl_client_certificate_request_type</c>.
+    /// </summary>
+    public enum SslClientCertificateRequestType {
+        /// <summary>
+        /// Server does not request client certificate.
+        /// The certificate presented by the client is not checked by the server at
+        /// all. (A client may present a self signed or signed certificate or not
+        /// present a certificate at all and any of those option would be accepted)
+        /// </summary>
+        DontRequestClientCertificate = 0,
+        /// <summary>
+        /// Server requests client certificate but does not enforce that the client
+        /// presents a certificate.
+        /// If the client presents a certificate, the client authentication is left to
+        /// the application (the necessary metadata will be available to the
+        /// application via authentication context properties, see grpc_auth_context).
+        /// The client's key certificate pair must be valid for the SSL connection to
+        /// be established.
+        ///</summary>
+        RequestClientCertificateButDontVerify,
+        /// <summary>
+        /// Server requests client certificate but does not enforce that the client
+        /// presents a certificate.
+        /// If the client presents a certificate, the client authentication is done by
+        /// the gRPC framework. (For a successful connection the client needs to either
+        /// present a certificate that can be verified against the root certificate
+        /// configured by the server or not present a certificate at all)
+        /// The client's key certificate pair must be valid for the SSL connection to
+        /// be established.
+        /// </summary>
+        RequestClientCertificateAndVerify,
+        /// <summary>
+        /// Server requests client certificate and enforces that the client presents a
+        /// certificate.
+        /// If the client presents a certificate, the client authentication is left to
+        /// the application (the necessary metadata will be available to the
+        /// application via authentication context properties, see grpc_auth_context).
+        /// The client's key certificate pair must be valid for the SSL connection to
+        /// be established.
+        ///</summary>
+        RequestAndRequireClientCertificateButDontVerify,
+        /// <summary>
+        /// Server requests client certificate and enforces that the client presents a
+        /// certificate.
+        /// The cerificate presented by the client is verified by the gRPC framework.
+        /// (For a successful connection the client needs to present a certificate that
+        /// can be verified against the root certificate configured by the server)
+        /// The client's key certificate pair must be valid for the SSL connection to
+        /// be established.
+        /// </summary>
+        RequestAndRequireClientCertificateAndVerify,
+    }
     /// <summary>
     /// Server-side SSL credentials.
     /// </summary>
@@ -64,35 +118,45 @@ namespace Grpc.Core
     {
         readonly IList<KeyCertificatePair> keyCertificatePairs;
         readonly string rootCertificates;
-        readonly bool forceClientAuth;
+        readonly SslClientCertificateRequestType clientCertificateRequest;
 
         /// <summary>
         /// Creates server-side SSL credentials.
         /// </summary>
         /// <param name="keyCertificatePairs">Key-certificates to use.</param>
         /// <param name="rootCertificates">PEM encoded client root certificates used to authenticate client.</param>
-        /// <param name="forceClientAuth">If true, client will be rejected unless it proves its unthenticity using against rootCertificates.</param>
+        /// <param name="forceClientAuth">Deprecated, use clientCertificateRequest overload instead.</param>
         public SslServerCredentials(IEnumerable<KeyCertificatePair> keyCertificatePairs, string rootCertificates, bool forceClientAuth)
+            : this(keyCertificatePairs, rootCertificates, forceClientAuth ? SslClientCertificateRequestType.RequestAndRequireClientCertificateAndVerify : SslClientCertificateRequestType.DontRequestClientCertificate)
+        {
+        }
+
+        /// <summary>
+        /// Creates server-side SSL credentials.
+        /// </summary>
+        /// <param name="keyCertificatePairs">Key-certificates to use.</param>
+        /// <param name="rootCertificates">PEM encoded client root certificates used to authenticate client.</param>
+        /// <param name="clientCertificateRequest">Options for requesting and verification of client certificate.</param>
+        public SslServerCredentials(IEnumerable<KeyCertificatePair> keyCertificatePairs, string rootCertificates, SslClientCertificateRequestType clientCertificateRequest)
         {
             this.keyCertificatePairs = new List<KeyCertificatePair>(keyCertificatePairs).AsReadOnly();
             GrpcPreconditions.CheckArgument(this.keyCertificatePairs.Count > 0,
                 "At least one KeyCertificatePair needs to be provided.");
-            if (forceClientAuth)
+            if (clientCertificateRequest == SslClientCertificateRequestType.RequestAndRequireClientCertificateAndVerify)
             {
                 GrpcPreconditions.CheckNotNull(rootCertificates,
-                    "Cannot force client authentication unless you provide rootCertificates.");
+                    "Cannot require and verify client certificate unless you provide rootCertificates.");
             }
             this.rootCertificates = rootCertificates;
-            this.forceClientAuth = forceClientAuth;
+            this.clientCertificateRequest = clientCertificateRequest;
         }
 
         /// <summary>
         /// Creates server-side SSL credentials.
-        /// This constructor should be use if you do not wish to autheticate client
-        /// using client root certificates.
+        /// This constructor should be use if you do not wish to autheticate client at all.
         /// </summary>
         /// <param name="keyCertificatePairs">Key-certificates to use.</param>
-        public SslServerCredentials(IEnumerable<KeyCertificatePair> keyCertificatePairs) : this(keyCertificatePairs, null, false)
+        public SslServerCredentials(IEnumerable<KeyCertificatePair> keyCertificatePairs) : this(keyCertificatePairs, null, SslClientCertificateRequestType.DontRequestClientCertificate)
         {
         }
 
@@ -119,13 +183,24 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// If true, the authenticity of client check will be enforced.
+        /// Deprecated. If true, the authenticity of client check will be enforced.
         /// </summary>
         public bool ForceClientAuthentication
         {
             get
             {
-                return this.forceClientAuth;
+                return this.clientCertificateRequest == SslClientCertificateRequestType.RequestAndRequireClientCertificateAndVerify;
+            }
+        }
+
+        /// <summary>
+        /// Mode of requesting certificate from client by the server.
+        /// </summary>
+        public SslClientCertificateRequestType ClientCertificateRequest
+        {
+            get
+            {
+                return this.clientCertificateRequest;
             }
         }
 
@@ -139,7 +214,7 @@ namespace Grpc.Core
                 certChains[i] = keyCertificatePairs[i].CertificateChain;
                 keys[i] = keyCertificatePairs[i].PrivateKey;
             }
-            return ServerCredentialsSafeHandle.CreateSslCredentials(rootCertificates, certChains, keys, forceClientAuth);
+            return ServerCredentialsSafeHandle.CreateSslCredentials(rootCertificates, certChains, keys, clientCertificateRequest);
         }
     }
 }

src/csharp/Grpc.IntegrationTesting/SslCredentialsTest.cs

@@ -37,20 +37,24 @@ namespace Grpc.IntegrationTesting
     public class SslCredentialsTest
     {
         const string Host = "localhost";
+        const string IsPeerAuthenticatedMetadataKey = "test_only_is_peer_authenticated";
         Server server;
         Channel channel;
         TestService.TestServiceClient client;
 
-        [OneTimeSetUp]
-        public void Init()
+        string rootCert;
+        KeyCertificatePair keyCertPair;
+
+        public void InitClientAndServer(bool clientAddKeyCertPair,
+                SslClientCertificateRequestType clientCertRequestType)
         {
-            var rootCert = File.ReadAllText(TestCredentials.ClientCertAuthorityPath);
-            var keyCertPair = new KeyCertificatePair(
+            rootCert = File.ReadAllText(TestCredentials.ClientCertAuthorityPath);
+            keyCertPair = new KeyCertificatePair(
                 File.ReadAllText(TestCredentials.ServerCertChainPath),
                 File.ReadAllText(TestCredentials.ServerPrivateKeyPath));
 
-            var serverCredentials = new SslServerCredentials(new[] { keyCertPair }, rootCert, true);
-            var clientCredentials = new SslCredentials(rootCert, keyCertPair);
+            var serverCredentials = new SslServerCredentials(new[] { keyCertPair }, rootCert, clientCertRequestType);
+            var clientCredentials = clientAddKeyCertPair ? new SslCredentials(rootCert, keyCertPair) : new SslCredentials(rootCert);
 
             // Disable SO_REUSEPORT to prevent https://github.com/grpc/grpc/issues/10755
             server = new Server(new[] { new ChannelOption(ChannelOptions.SoReuseport, 0) })
@@ -72,19 +76,133 @@ namespace Grpc.IntegrationTesting
         [OneTimeTearDown]
         public void Cleanup()
         {
-            channel.ShutdownAsync().Wait();
-            server.ShutdownAsync().Wait();
+            if (channel != null)
+            {
+                channel.ShutdownAsync().Wait();
+            }
+            if (server != null)
+            {
+                server.ShutdownAsync().Wait();
+            }
         }
 
         [Test]
-        public void AuthenticatedClientAndServer()
+        public async Task NoClientCert_DontRequestClientCertificate_Accepted()
         {
-            var response = client.UnaryCall(new SimpleRequest { ResponseSize = 10 });
-            Assert.AreEqual(10, response.Payload.Body.Length);
+            InitClientAndServer(
+                clientAddKeyCertPair: false,
+                clientCertRequestType: SslClientCertificateRequestType.DontRequestClientCertificate);
+
+            await CheckAccepted(expectPeerAuthenticated: false);
         }
 
         [Test]
-        public async Task AuthContextIsPopulated()
+        public async Task ClientWithCert_DontRequestClientCertificate_AcceptedButPeerNotAuthenticated()
+        {
+            InitClientAndServer(
+                clientAddKeyCertPair: true,
+                clientCertRequestType: SslClientCertificateRequestType.DontRequestClientCertificate);
+
+            await CheckAccepted(expectPeerAuthenticated: false);
+        }
+
+        [Test]
+        public async Task NoClientCert_RequestClientCertificateButDontVerify_Accepted()
+        {
+            InitClientAndServer(
+                clientAddKeyCertPair: false,
+                clientCertRequestType: SslClientCertificateRequestType.RequestClientCertificateButDontVerify);
+
+            await CheckAccepted(expectPeerAuthenticated: false);
+        }
+
+        [Test]
+        public async Task NoClientCert_RequestClientCertificateAndVerify_Accepted()
+        {
+            InitClientAndServer(
+                clientAddKeyCertPair: false,
+                clientCertRequestType: SslClientCertificateRequestType.RequestClientCertificateAndVerify);
+
+            await CheckAccepted(expectPeerAuthenticated: false);
+        }
+
+        [Test]
+        public async Task ClientWithCert_RequestAndRequireClientCertificateButDontVerify_Accepted()
+        {
+            InitClientAndServer(
+                clientAddKeyCertPair: true,
+                clientCertRequestType: SslClientCertificateRequestType.RequestAndRequireClientCertificateButDontVerify);
+
+            await CheckAccepted(expectPeerAuthenticated: true);
+            await CheckAuthContextIsPopulated();
+        }
+
+        [Test]
+        public async Task ClientWithCert_RequestAndRequireClientCertificateAndVerify_Accepted()
+        {
+            InitClientAndServer(
+                clientAddKeyCertPair: true,
+                clientCertRequestType: SslClientCertificateRequestType.RequestAndRequireClientCertificateAndVerify);
+
+            await CheckAccepted(expectPeerAuthenticated: true);
+            await CheckAuthContextIsPopulated();
+        }
+
+        [Test]
+        public void NoClientCert_RequestAndRequireClientCertificateButDontVerify_Rejected()
+        {
+            InitClientAndServer(
+                clientAddKeyCertPair: false,
+                clientCertRequestType: SslClientCertificateRequestType.RequestAndRequireClientCertificateButDontVerify);
+
+            CheckRejected();
+        }
+
+        [Test]
+        public void NoClientCert_RequestAndRequireClientCertificateAndVerify_Rejected()
+        {
+            InitClientAndServer(
+                clientAddKeyCertPair: false,
+                clientCertRequestType: SslClientCertificateRequestType.RequestAndRequireClientCertificateAndVerify);
+
+            CheckRejected();
+        }
+
+        [Test]
+        public void Constructor_LegacyForceClientAuth()
+        {
+            var creds = new SslServerCredentials(new[] { keyCertPair }, rootCert, true);
+            Assert.AreEqual(SslClientCertificateRequestType.RequestAndRequireClientCertificateAndVerify, creds.ClientCertificateRequest);
+
+            var creds2 = new SslServerCredentials(new[] { keyCertPair }, rootCert, false);
+            Assert.AreEqual(SslClientCertificateRequestType.DontRequestClientCertificate, creds2.ClientCertificateRequest);
+        }
+
+        [Test]
+        public void Constructor_NullRootCerts()
+        {
+            var keyCertPairs = new[] { keyCertPair };
+            new SslServerCredentials(keyCertPairs, null, SslClientCertificateRequestType.DontRequestClientCertificate);
+            new SslServerCredentials(keyCertPairs, null, SslClientCertificateRequestType.RequestClientCertificateAndVerify);
+            new SslServerCredentials(keyCertPairs, null, SslClientCertificateRequestType.RequestAndRequireClientCertificateButDontVerify);
+            Assert.Throws(typeof(ArgumentNullException), () => new SslServerCredentials(keyCertPairs, null, SslClientCertificateRequestType.RequestAndRequireClientCertificateAndVerify));
+        }
+
+        private async Task CheckAccepted(bool expectPeerAuthenticated)
+        {
+            var call = client.UnaryCallAsync(new SimpleRequest { ResponseSize = 10 });
+            var response = await call;
+            Assert.AreEqual(10, response.Payload.Body.Length);
+            Assert.AreEqual(expectPeerAuthenticated.ToString(), call.GetTrailers().First((entry) => entry.Key == IsPeerAuthenticatedMetadataKey).Value);
+        }
+
+        private void CheckRejected()
+        {
+            var ex = Assert.Throws<RpcException>(() => client.UnaryCall(new SimpleRequest { ResponseSize = 10 }));
+            Assert.AreEqual(StatusCode.Unavailable, ex.Status.StatusCode);
+        }
+
+        private async Task CheckAuthContextIsPopulated()
         {
             var call = client.StreamingInputCall();
             await call.RequestStream.CompleteAsync();
@@ -96,6 +214,7 @@ namespace Grpc.IntegrationTesting
         {
             public override Task<SimpleResponse> UnaryCall(SimpleRequest request, ServerCallContext context)
             {
+                context.ResponseTrailers.Add(IsPeerAuthenticatedMetadataKey, context.AuthContext.IsPeerAuthenticated.ToString());
                 return Task.FromResult(new SimpleResponse { Payload = CreateZerosPayload(request.ResponseSize) });
             }
 

src/csharp/ext/grpc_csharp_ext.c

@@ -964,7 +964,7 @@ GPR_EXPORT grpc_server_credentials* GPR_CALLTYPE
 grpcsharp_ssl_server_credentials_create(
     const char* pem_root_certs, const char** key_cert_pair_cert_chain_array,
     const char** key_cert_pair_private_key_array, size_t num_key_cert_pairs,
-    int force_client_auth) {
+    grpc_ssl_client_certificate_request_type client_request_type) {
   size_t i;
   grpc_server_credentials* creds;
   grpc_ssl_pem_key_cert_pair* key_cert_pairs =
@@ -981,9 +981,7 @@ grpcsharp_ssl_server_credentials_create(
   }
   creds = grpc_ssl_server_credentials_create_ex(
       pem_root_certs, key_cert_pairs, num_key_cert_pairs,
-      force_client_auth
-          ? GRPC_SSL_REQUEST_AND_REQUIRE_CLIENT_CERTIFICATE_AND_VERIFY
-          : GRPC_SSL_DONT_REQUEST_CLIENT_CERTIFICATE,
+      client_request_type,
       NULL);
   gpr_free(key_cert_pairs);
   return creds;

templates/src/csharp/Grpc.Core/Internal/NativeMethods.Generated.cs.template

@@ -73,7 +73,7 @@
       'void grpcsharp_redirect_log(GprLogDelegate callback)',
       'CallCredentialsSafeHandle grpcsharp_metadata_credentials_create_from_plugin(NativeMetadataInterceptor interceptor)',
       'void grpcsharp_metadata_credentials_notify_from_plugin(IntPtr callbackPtr, IntPtr userData, MetadataArraySafeHandle metadataArray, StatusCode statusCode, string errorDetails)',
-      'ServerCredentialsSafeHandle grpcsharp_ssl_server_credentials_create(string pemRootCerts, string[] keyCertPairCertChainArray, string[] keyCertPairPrivateKeyArray, UIntPtr numKeyCertPairs, int forceClientAuth)',
+      'ServerCredentialsSafeHandle grpcsharp_ssl_server_credentials_create(string pemRootCerts, string[] keyCertPairCertChainArray, string[] keyCertPairPrivateKeyArray, UIntPtr numKeyCertPairs, SslClientCertificateRequestType clientCertificateRequest)',
       'void grpcsharp_server_credentials_release(IntPtr credentials)',
       'ServerSafeHandle grpcsharp_server_create(ChannelArgsSafeHandle args)',
       'void grpcsharp_server_register_completion_queue(ServerSafeHandle server, CompletionQueueSafeHandle cq)',