Add callback to customize Kerberos authentication options (npgsql#5775)

Closes npgsql#5181

src/Npgsql/Internal/NpgsqlConnector.Auth.cs

@@ -334,7 +334,10 @@ internal async Task AuthenticateGSS(bool async)
     {
         var targetName = $"{KerberosServiceName}/{Host}";
 
-        using var authContext = new NegotiateAuthentication(new NegotiateAuthenticationClientOptions{ TargetName = targetName});
+        var clientOptions = new NegotiateAuthenticationClientOptions { TargetName = targetName };
+        NegotiateOptionsCallback?.Invoke(clientOptions);
+
+        using var authContext = new NegotiateAuthentication(clientOptions);
         var data = authContext.GetOutgoingBlob(ReadOnlySpan<byte>.Empty, out var statusCode)!;
         Debug.Assert(statusCode == NegotiateAuthenticationStatusCode.ContinueNeeded);
         await WritePassword(data, 0, data.Length, async, UserCancellationToken).ConfigureAwait(false);

src/Npgsql/Internal/NpgsqlConnector.cs

@@ -61,6 +61,10 @@ public sealed partial class NpgsqlConnector
     ProvidePasswordCallback? ProvidePasswordCallback { get; }
 #pragma warning restore CS0618
 
+#if NET7_0_OR_GREATER
+    Action<NegotiateAuthenticationClientOptions>? NegotiateOptionsCallback { get; }
+#endif
+
     public Encoding TextEncoding { get; private set; } = default!;
 
     /// <summary>
@@ -366,6 +370,10 @@ internal NpgsqlConnector(NpgsqlDataSource dataSource, NpgsqlConnection conn)
         ClientCertificatesCallback = dataSource.ClientCertificatesCallback;
         UserCertificateValidationCallback = dataSource.UserCertificateValidationCallback;
 
+#if NET7_0_OR_GREATER
+        NegotiateOptionsCallback = dataSource.Configuration.NegotiateOptionsCallback;
+#endif
+
         State = ConnectorState.Closed;
         TransactionStatus = TransactionStatus.Idle;
         Settings = dataSource.Settings;

src/Npgsql/NpgsqlDataSource.cs

@@ -108,7 +108,11 @@ internal NpgsqlDataSource(
                 var resolverChain,
                 _defaultNameTranslator,
                 ConnectionInitializer,
-                ConnectionInitializerAsync)
+                ConnectionInitializerAsync
+#if NET7_0_OR_GREATER
+                ,_
+#endif
+                )
             = dataSourceConfig;
         _connectionLogger = LoggingConfiguration.ConnectionLogger;
 

src/Npgsql/NpgsqlDataSourceBuilder.cs

@@ -325,6 +325,24 @@ public NpgsqlDataSourceBuilder UsePasswordProvider(
         return this;
     }
 
+#if NET7_0_OR_GREATER
+    /// <summary>
+    /// When using Kerberos, this is a callback that allows customizing default settings for Kerberos authentication.
+    /// </summary>
+    /// <param name="negotiateOptionsCallback">The callback containing logic to customize Kerberos authentication settings.</param>
+    /// <remarks>
+    /// <para>
+    /// See <see href="https://learn.microsoft.com/en-us/dotnet/api/system.net.security.negotiateauthenticationclientoptions?view=net-7.0"/>.
+    /// </para>
+    /// </remarks>
+    /// <returns>The same builder instance so that multiple calls can be chained.</returns>
+    public NpgsqlDataSourceBuilder UseNegotiateOptionsCallback(Action<NegotiateAuthenticationClientOptions>? negotiateOptionsCallback)
+    {
+        _internalBuilder.UseNegotiateOptionsCallback(negotiateOptionsCallback);
+        return this;
+    }
+#endif
+
     #endregion Authentication
 
     #region Type mapping

src/Npgsql/NpgsqlDataSourceConfiguration.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using System.Net.Security;
 using System.Security.Cryptography.X509Certificates;
 using System.Threading;
@@ -22,4 +21,8 @@ sealed record NpgsqlDataSourceConfiguration(string? Name,
     PgTypeInfoResolverChain ResolverChain,
     INpgsqlNameTranslator DefaultNameTranslator,
     Action<NpgsqlConnection>? ConnectionInitializer,
-    Func<NpgsqlConnection, Task>? ConnectionInitializerAsync);
+    Func<NpgsqlConnection, Task>? ConnectionInitializerAsync
+#if NET7_0_OR_GREATER
+    ,Action<NegotiateAuthenticationClientOptions>? NegotiateOptionsCallback
+#endif
+    );

src/Npgsql/NpgsqlSlimDataSourceBuilder.cs

@@ -34,6 +34,10 @@ public sealed class NpgsqlSlimDataSourceBuilder : INpgsqlTypeMapper
     RemoteCertificateValidationCallback? _userCertificateValidationCallback;
     Action<X509CertificateCollection>? _clientCertificatesCallback;
 
+#if NET7_0_OR_GREATER
+    Action<NegotiateAuthenticationClientOptions>? _negotiateOptionsCallback;
+#endif
+
     IntegratedSecurityHandler _integratedSecurityHandler = new();
 
     Func<NpgsqlConnectionStringBuilder, string>? _passwordProvider;
@@ -289,6 +293,25 @@ public NpgsqlSlimDataSourceBuilder UsePasswordProvider(
         return this;
     }
 
+#if NET7_0_OR_GREATER
+    /// <summary>
+    /// When using Kerberos, this is a callback that allows customizing default settings for Kerberos authentication.
+    /// </summary>
+    /// <param name="negotiateOptionsCallback">The callback containing logic to customize Kerberos authentication settings.</param>
+    /// <remarks>
+    /// <para>
+    /// See <see href="https://learn.microsoft.com/en-us/dotnet/api/system.net.security.negotiateauthenticationclientoptions?view=net-7.0"/>.
+    /// </para>
+    /// </remarks>
+    /// <returns>The same builder instance so that multiple calls can be chained.</returns>
+    public NpgsqlSlimDataSourceBuilder UseNegotiateOptionsCallback(Action<NegotiateAuthenticationClientOptions>? negotiateOptionsCallback)
+    {
+        _negotiateOptionsCallback = negotiateOptionsCallback;
+
+        return this;
+    }
+#endif
+
     #endregion Authentication
 
     #region Type mapping
@@ -602,7 +625,7 @@ public NpgsqlDataSource Build()
         var config = PrepareConfiguration();
         var connectionStringBuilder = ConnectionStringBuilder.Clone();
 
-        if (ConnectionStringBuilder.Host!.Contains(","))
+        if (ConnectionStringBuilder.Host!.Contains(','))
         {
             ValidateMultiHost();
 
@@ -667,7 +690,11 @@ _loggerFactory is null
             _resolverChainBuilder.Build(ConfigureResolverChain),
             DefaultNameTranslator,
             _connectionInitializer,
-            _connectionInitializerAsync);
+            _connectionInitializerAsync
+#if NET7_0_OR_GREATER
+            ,_negotiateOptionsCallback
+#endif
+            );
     }
 
     void ValidateMultiHost()

src/Npgsql/PublicAPI.Unshipped.txt

@@ -1,7 +1,9 @@
 #nullable enable
+Npgsql.NpgsqlDataSourceBuilder.UseNegotiateOptionsCallback(System.Action<System.Net.Security.NegotiateAuthenticationClientOptions!>? negotiateOptionsCallback) -> Npgsql.NpgsqlDataSourceBuilder!
 Npgsql.NpgsqlSlimDataSourceBuilder.EnableGeometricTypes() -> Npgsql.NpgsqlSlimDataSourceBuilder!
 Npgsql.NpgsqlSlimDataSourceBuilder.EnableJsonTypes() -> Npgsql.NpgsqlSlimDataSourceBuilder!
 Npgsql.NpgsqlSlimDataSourceBuilder.EnableNetworkTypes() -> Npgsql.NpgsqlSlimDataSourceBuilder!
+Npgsql.NpgsqlSlimDataSourceBuilder.UseNegotiateOptionsCallback(System.Action<System.Net.Security.NegotiateAuthenticationClientOptions!>? negotiateOptionsCallback) -> Npgsql.NpgsqlSlimDataSourceBuilder!
 Npgsql.Replication.PgOutput.ReplicationValue.GetFieldName() -> string!
 Npgsql.Replication.PgOutput.Messages.ParallelStreamAbortMessage
 Npgsql.Replication.PgOutput.Messages.ParallelStreamAbortMessage.AbortLsn.get -> NpgsqlTypes.NpgsqlLogSequenceNumber