[System.DirectoryServices] Fixed possible resource leak

src/libraries/System.DirectoryServices/src/System/DirectoryServices/ActiveDirectory/TrustHelper.cs

@@ -28,7 +28,6 @@
 
         internal static unsafe bool GetTrustedDomainInfoStatus(DirectoryContext context, string? sourceName, string targetName, Interop.Advapi32.TRUST_ATTRIBUTE attribute, bool isForest)
         {
-            SafeLsaPolicyHandle? handle = null;
             IntPtr buffer = (IntPtr)0;
             bool impersonated = false;
             IntPtr target = (IntPtr)0;
@@ -44,7 +43,7 @@
                 try
                 {
                     // get the policy handle first
-                    handle = Utils.GetPolicyHandle(serverName);
+                    using var handle = Utils.GetPolicyHandle(serverName);
 
                     // get the target name
                     global::Interop.UNICODE_STRING trustedDomainName;
@@ -123,7 +122,6 @@
 
         internal static unsafe void SetTrustedDomainInfoStatus(DirectoryContext context, string? sourceName, string targetName, Interop.Advapi32.TRUST_ATTRIBUTE attribute, bool status, bool isForest)
         {
-            SafeLsaPolicyHandle? handle = null;
             IntPtr buffer = (IntPtr)0;
             IntPtr newInfo = (IntPtr)0;
             bool impersonated = false;
@@ -139,7 +137,7 @@
                 try
                 {
                     // get the policy handle first
-                    handle = Utils.GetPolicyHandle(serverName);
+                    using var handle = Utils.GetPolicyHandle(serverName);
 
                     // get the target name
                     global::Interop.UNICODE_STRING trustedDomainName;
@@ -251,7 +249,6 @@
 
         internal static unsafe void DeleteTrust(DirectoryContext sourceContext, string? sourceName, string? targetName, bool isForest)
         {
-            SafeLsaPolicyHandle? policyHandle = null;
             bool impersonated = false;
             IntPtr target = (IntPtr)0;
             string? serverName = null;
@@ -266,7 +263,7 @@
                 try
                 {
                     // get the policy handle
-                    policyHandle = Utils.GetPolicyHandle(serverName);
+                    using var policyHandle = Utils.GetPolicyHandle(serverName);
 
                     // get the target name
                     global::Interop.UNICODE_STRING trustedDomainName;
@@ -327,7 +324,6 @@
 
         internal static void VerifyTrust(DirectoryContext context, string? sourceName, string? targetName, bool isForest, TrustDirection direction, bool forceSecureChannelReset, string? preferredTargetServer)
         {
-            SafeLsaPolicyHandle? policyHandle = null;
             int win32Error = 0;
             IntPtr data = (IntPtr)0;
             IntPtr ptr = (IntPtr)0;
@@ -346,7 +342,7 @@
                 try
                 {
                     // get the policy handle
-                    policyHandle = Utils.GetPolicyHandle(policyServerName);
+                    using var policyHandle = Utils.GetPolicyHandle(policyServerName);
 
                     // get the target name
                     global::Interop.UNICODE_STRING trustedDomainName;
@@ -446,7 +442,6 @@
             IntPtr unmanagedPassword = (IntPtr)0;
             IntPtr info = (IntPtr)0;
             IntPtr domainHandle = (IntPtr)0;
-            SafeLsaPolicyHandle? policyHandle = null;
             IntPtr unmanagedAuthData = (IntPtr)0;
             bool impersonated = false;
             string? serverName = null;
@@ -517,7 +512,7 @@
 
                     // do impersonation and get policy handle
                     impersonated = Utils.Impersonate(sourceContext);
-                    policyHandle = Utils.GetPolicyHandle(serverName);
+                    using var policyHandle = Utils.GetPolicyHandle(serverName);
 
                     uint result = Interop.Advapi32.LsaCreateTrustedDomainEx(policyHandle, tdi, AuthInfoEx, TRUSTED_SET_POSIX | TRUSTED_SET_AUTH, out domainHandle);
                     if (result != 0)
@@ -560,7 +555,6 @@
 
         internal static unsafe string UpdateTrust(DirectoryContext context, string? sourceName, string? targetName, string password, bool isForest)
         {
-            SafeLsaPolicyHandle? handle = null;
             IntPtr buffer = (IntPtr)0;
             IntPtr newBuffer = (IntPtr)0;
             bool impersonated = false;
@@ -581,7 +575,7 @@
                 try
                 {
                     // get the policy handle first
-                    handle = Utils.GetPolicyHandle(serverName);
+                    using var handle = Utils.GetPolicyHandle(serverName);
 
                     // get the target name
                     global::Interop.UNICODE_STRING trustedDomainName;
@@ -691,7 +685,6 @@
 
         internal static unsafe void UpdateTrustDirection(DirectoryContext context, string? sourceName, string? targetName, string password, bool isForest, TrustDirection newTrustDirection)
         {
-            SafeLsaPolicyHandle? handle = null;
             IntPtr buffer = (IntPtr)0;
             IntPtr newBuffer = (IntPtr)0;
             bool impersonated = false;
@@ -711,7 +704,7 @@
                 try
                 {
                     // get the policy handle first
-                    handle = Utils.GetPolicyHandle(serverName);
+                    using var handle = Utils.GetPolicyHandle(serverName);
 
                     // get the target name
                     global::Interop.UNICODE_STRING trustedDomainName;
@@ -1016,6 +1009,8 @@
                 }
                 finally
                 {
+                    policyHandle?.Dispose();
+
                     if (impersonated)
                         Utils.Revert();
                 }