Fix | Linux SPN port number using named instance and Kerberos authentication does not return port#

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SNI/SNIProxy.cs

@@ -230,7 +230,7 @@ private static byte[][] GetSqlServerSPNs(DataSource dataSource, string serverSPN
             }
             else if (!string.IsNullOrWhiteSpace(dataSource.InstanceName))
             {
-                postfix = dataSource.InstanceName;
+                postfix = dataSource._connectionProtocol == DataSource.Protocol.TCP ? dataSource.ResolvedPort.ToString() : dataSource.InstanceName;
             }
 
             SqlClientEventSource.Log.TryTraceEvent("SNIProxy.GetSqlServerSPN | Info | ServerName {0}, InstanceName {1}, Port {2}, postfix {3}", dataSource?.ServerName, dataSource?.InstanceName, dataSource?.Port, postfix);
@@ -317,7 +317,7 @@ private static SNITCPHandle CreateTcpHandle(
             {
                 try
                 {
-                    port = isAdminConnection ?
+                    details.ResolvedPort = port = isAdminConnection ?
                             SSRP.GetDacPortByInstanceName(hostName, details.InstanceName, timeout, parallel, ipPreference) :
                             SSRP.GetPortByInstanceName(hostName, details.InstanceName, timeout, parallel, ipPreference);
                 }
@@ -436,6 +436,11 @@ internal enum Protocol { TCP, NP, None, Admin };
         /// </summary>
         internal int Port { get; private set; } = -1;
 
+        /// <summary>
+        /// The port resolved by SSRP when InstanceName is specified
+        /// </summary>
+        internal int ResolvedPort { get; set; } = -1;
+
         /// <summary>
         /// Provides the inferred Instance Name from Server Data Source
         /// </summary>

src/Microsoft.Data.SqlClient/tests/ManualTests/DataCommon/DataTestUtility.cs

@@ -1073,6 +1073,21 @@ public static string GetMachineFQDN(string hostname)
             return fqdn.ToString();
         }
 
+        public static bool IsNotLocalhost()
+        {
+            // get the tcp connection string
+            SqlConnectionStringBuilder builder = new(DataTestUtility.TCPConnectionString);
+
+            string hostname = "";
+
+            // parse the datasource
+            ParseDataSource(builder.DataSource, out hostname, out _, out _);
+
+            // hostname must not be localhost, ., 127.0.0.1 nor ::1
+            return !(new string[] { "localhost", ".", "127.0.0.1", "::1" }).Contains(hostname.ToLowerInvariant());
+
+        }
+
         private static bool RunningAsUWPApp()
         {
             if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))

src/Microsoft.Data.SqlClient/tests/ManualTests/SQL/InstanceNameTest/InstanceNameTest.cs

@@ -5,6 +5,7 @@
 using System;
 using System.Net;
 using System.Net.Sockets;
+using System.Reflection;
 using System.Text;
 using System.Threading.Tasks;
 using Xunit;
@@ -83,6 +84,138 @@ public static void ConnectManagedWithInstanceNameTest(bool useMultiSubnetFailove
             }
         }
 
+        // Note: This Unit test was tested in a domain-joined VM connecting to a remote
+        //       SQL Server using Kerberos in the same domain.
+        [ActiveIssue("27824")] // When specifying instance name and port number, this method call always returns false
+        [ConditionalFact(nameof(IsKerberos))]
+        public static void PortNumberInSPNTest()
+        {
+            string connStr = DataTestUtility.TCPConnectionString;
+            // If config.json.SupportsIntegratedSecurity = true, replace all keys defined below with Integrated Security=true 
+            if (DataTestUtility.IsIntegratedSecuritySetup())
+            {
+                string[] removeKeys = { "Authentication", "User ID", "Password", "UID", "PWD", "Trusted_Connection" };
+                connStr = DataTestUtility.RemoveKeysInConnStr(DataTestUtility.TCPConnectionString, removeKeys) + $"Integrated Security=true";
+            }
+
+            SqlConnectionStringBuilder builder = new(connStr);
+
+            Assert.True(DataTestUtility.ParseDataSource(builder.DataSource, out string hostname, out _, out string instanceName), "Data source to be parsed must contain a host name and instance name");
+
+            bool condition = IsBrowserAlive(hostname) && IsValidInstance(hostname, instanceName);
+            Assert.True(condition, "Browser service is not running or instance name is invalid");
+
+            if (condition)
+            {
+                using SqlConnection connection = new(builder.ConnectionString);
+                connection.Open();
+                using SqlCommand command = new("SELECT auth_scheme, local_tcp_port from sys.dm_exec_connections where session_id = @@spid", connection);
+                using SqlDataReader reader = command.ExecuteReader();
+                Assert.True(reader.Read(), "Expected to receive one row data");
+                Assert.Equal("KERBEROS", reader.GetString(0));
+                int localTcpPort = reader.GetInt32(1);
+
+                int spnPort = -1;
+                string spnInfo = GetSPNInfo(builder.DataSource, out spnPort);
+
+                // sample output to validate = MSSQLSvc/machine.domain.tld:spnPort"
+                Assert.Contains($"MSSQLSvc/{hostname}", spnInfo);
+                // the local_tcp_port should be the same as the inferred SPN port from instance name
+                Assert.Equal(localTcpPort, spnPort);
+            }
+        }
+
+        private static string GetSPNInfo(string datasource, out int out_port)
+        {
+            Assembly sqlConnectionAssembly = Assembly.GetAssembly(typeof(SqlConnection));
+
+            // Get all required types using reflection
+            Type sniProxyType = sqlConnectionAssembly.GetType("Microsoft.Data.SqlClient.SNI.SNIProxy");
+            Type ssrpType = sqlConnectionAssembly.GetType("Microsoft.Data.SqlClient.SNI.SSRP");
+            Type dataSourceType = sqlConnectionAssembly.GetType("Microsoft.Data.SqlClient.SNI.DataSource");
+            Type timeoutTimerType = sqlConnectionAssembly.GetType("Microsoft.Data.ProviderBase.TimeoutTimer");
+
+            // Used in Datasource constructor param type array 
+            Type[] dataSourceConstructorTypesArray = new Type[] { typeof(string) };
+
+            // Used in GetSqlServerSPNs function param types array
+            Type[] getSqlServerSPNsTypesArray = new Type[] { dataSourceType, typeof(string) };
+
+            // GetPortByInstanceName parameters array
+            Type[] getPortByInstanceNameTypesArray = new Type[] { typeof(string), typeof(string), timeoutTimerType, typeof(bool), typeof(Microsoft.Data.SqlClient.SqlConnectionIPAddressPreference) };
+
+            // TimeoutTimer.StartSecondsTimeout params
+            Type[] startSecondsTimeoutTypesArray = new Type[] { typeof(int) };
+
+            // Get all types constructors
+            ConstructorInfo sniProxyCtor = sniProxyType.GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, CallingConventions.Any, Type.EmptyTypes, null);
+            ConstructorInfo SSRPCtor = ssrpType.GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, CallingConventions.Any, Type.EmptyTypes, null);
+            ConstructorInfo dataSourceCtor = dataSourceType.GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, CallingConventions.Any, dataSourceConstructorTypesArray, null);
+            ConstructorInfo timeoutTimerCtor = timeoutTimerType.GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, CallingConventions.Any, Type.EmptyTypes, null);
+
+            // Instantiate SNIProxy
+            object sniProxy = sniProxyCtor.Invoke(new object[] { });
+
+            // Instantiate datasource 
+            object dataSourceObj = dataSourceCtor.Invoke(new object[] { datasource });
+
+            // Instantiate SSRP
+            object ssrp = SSRPCtor.Invoke(new object[] { });
+
+            // Instantiate TimeoutTimer
+            object timeoutTimer = timeoutTimerCtor.Invoke(new object[] { });
+
+            // Get TimeoutTimer.StartSecondsTimeout Method
+            MethodInfo startSecondsTimeout = timeoutTimer.GetType().GetMethod("StartSecondsTimeout", BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic, null, CallingConventions.Any, startSecondsTimeoutTypesArray, null);
+            // Create a timeoutTimer that expires in 30 seconds
+            timeoutTimer = startSecondsTimeout.Invoke(dataSourceObj, new object[] { 30 });
+
+            // Parse the datasource to separate the server name and instance name
+            MethodInfo ParseServerName = dataSourceObj.GetType().GetMethod("ParseServerName", BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic, null, CallingConventions.Any, dataSourceConstructorTypesArray, null);
+            object dataSrcInfo = ParseServerName.Invoke(dataSourceObj, new object[] { datasource });
+
+            // Get the GetPortByInstanceName method of SSRP
+            MethodInfo getPortByInstanceName = ssrp.GetType().GetMethod("GetPortByInstanceName", BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic, null, CallingConventions.Any, getPortByInstanceNameTypesArray, null);
+
+            // Get the server name
+            PropertyInfo serverInfo = dataSrcInfo.GetType().GetProperty("ServerName", BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
+            string serverName = serverInfo.GetValue(dataSrcInfo, null).ToString();
+
+            // Get the instance name
+            PropertyInfo instanceNameInfo = dataSrcInfo.GetType().GetProperty("InstanceName", BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
+            string instanceName = instanceNameInfo.GetValue(dataSrcInfo, null).ToString();
+
+            // Get the port number using the GetPortByInstanceName method of SSRP
+            object port = getPortByInstanceName.Invoke(ssrp, parameters: new object[] { serverName, instanceName, timeoutTimer, false, 0 });
+
+            // Set the resolved port property of datasource
+            PropertyInfo resolvedPortInfo = dataSrcInfo.GetType().GetProperty("ResolvedPort", BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
+            resolvedPortInfo.SetValue(dataSrcInfo, (int)port, null);
+
+            // Prepare the GetSqlServerSPNs method
+            string serverSPN = "";
+            MethodInfo getSqlServerSPNs = sniProxy.GetType().GetMethod("GetSqlServerSPNs", BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic, null, CallingConventions.Any, getSqlServerSPNsTypesArray, null);
+
+            // Finally call GetSqlServerSPNs
+            byte[][] result = (byte[][])getSqlServerSPNs.Invoke(sniProxy, new object[] { dataSrcInfo, serverSPN });
+
+            // Example result: MSSQLSvc/machine.domain.tld:port"
+            string spnInfo = Encoding.Unicode.GetString(result[0]);
+
+            out_port = (int)port;
+
+            return spnInfo;
+        }
+
+        private static bool IsKerberos()
+        {
+            return (DataTestUtility.AreConnStringsSetup() 
+                 && DataTestUtility.IsNotLocalhost() 
+                 && DataTestUtility.IsKerberosTest 
+                 && DataTestUtility.IsNotAzureServer() 
+                 && DataTestUtility.IsNotAzureSynapse());
+        }
+
         private static bool IsBrowserAlive(string browserHostname)
         {
             const byte ClntUcastEx = 0x03;