Merged PR 10359054: Reintroduce SymCryptK.dll entry point to unblock SK

## Description:

+ Reverts change to remove entry point from SymCryptK.dll, as in local testing SymCryptK.dll with an entry point works with SK, while SymCryptK.dll without an entry point does not.

Related work items: #49201043

Author: samuel-lee-msft

modules/windows/kernel/main.c

@@ -20,6 +20,22 @@ SYMCRYPT_ENVIRONMENT_WINDOWS_KERNELMODE_LATEST;
 #define FIPS_SERVICE_DESC_SHOW_VERSION
 #include "../lib/status_indicator.h"
 
+// Our DriverEntry function is not used, as this module acts as an export driver which is linked
+// directly to the kernel. In other words, it's not initialized by WDF, and we don't create any
+// device objects or use other WDF functions. However, we need to define an entrypoint, or
+// secure kernel will be unable to load the module.
+NTSTATUS
+DriverEntry(
+    _In_  struct _DRIVER_OBJECT* DriverObject,
+    _In_ PUNICODE_STRING RegistryPath
+    )
+{
+    UNREFERENCED_PARAMETER( DriverObject );
+    UNREFERENCED_PARAMETER( RegistryPath );
+
+    return STATUS_SUCCESS;
+}
+
 void __cdecl __security_init_cookie(void);
 
 VOID SYMCRYPT_CALL SymCryptModuleInit(UINT32 api, UINT32 minor)

modules/windows/kernel/symcryptk.vcxproj

@@ -59,7 +59,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
       <AdditionalDependencies>%(AdditionalDependencies);ntoskrnl.lib</AdditionalDependencies>
-      <NoEntryPoint>true</NoEntryPoint>
+      <EntryPointSymbol>GsDriverEntry</EntryPointSymbol>
     </Link>
   </ItemDefinitionGroup>
   <PropertyGroup Label="DbgEng">