Switch to final registry key loading paradigm

1 files changed, 162 insertions, 39 deletions

diff --git a/filesys/miniFilter/MetadataManager/MetadataManagerInit.c b/filesys/miniFilter/MetadataManager/MetadataManagerInit.c
index 3b371360..dbedd3a8 100644
--- a/filesys/miniFilter/MetadataManager/MetadataManagerInit.c
+++ b/filesys/miniFilter/MetadataManager/MetadataManagerInit.c
@@ -86,6 +86,28 @@ FmmInstanceTeardownComplete (
 
 #if DBG
 
+typedef
+NTSTATUS
+(*PFN_IoOpenDriverRegistryKey) (
+    PDRIVER_OBJECT     DriverObject,
+    DRIVER_REGKEY_TYPE RegKeyType,
+    ACCESS_MASK        DesiredAccess,
+    ULONG              Flags,
+    PHANDLE            DriverRegKey
+    );
+
+PFN_IoOpenDriverRegistryKey
+FmmGetIoOpenDriverRegistryKey (
+    VOID
+    );
+
+NTSTATUS
+FmmOpenServiceParametersKey (
+    _In_ PDRIVER_OBJECT DriverObject,
+    _In_ PUNICODE_STRING ServiceRegistryPath,
+    _Out_ PHANDLE ServiceParametersKey
+    );
+
 VOID
 FmmInitializeDebugLevel (
     _In_ PDRIVER_OBJECT DriverObject,
@@ -102,6 +124,8 @@ FmmInitializeDebugLevel (
 #pragma alloc_text(INIT, DriverEntry)
 
 #if DBG
+#pragma alloc_text(INIT, FmmGetIoOpenDriverRegistryKey)
+#pragma alloc_text(INIT, FmmOpenServiceParametersKey)
 #pragma alloc_text(INIT, FmmInitializeDebugLevel)
 #endif
 
@@ -300,18 +324,36 @@ Return Value:
 
 #if DBG
 
-VOID
-FmmInitializeDebugLevel (
+PFN_IoOpenDriverRegistryKey
+FmmGetIoOpenDriverRegistryKey (
+    VOID
+    )
+{
+    static PFN_IoOpenDriverRegistryKey pIoOpenDriverRegistryKey = NULL;
+    UNICODE_STRING FunctionName = {0};
+
+    if (pIoOpenDriverRegistryKey == NULL) {
+
+        RtlInitUnicodeString(&FunctionName, L"IoOpenDriverRegistryKey");
+
+        pIoOpenDriverRegistryKey = (PFN_IoOpenDriverRegistryKey)MmGetSystemRoutineAddress(&FunctionName);
+    }
+
+    return pIoOpenDriverRegistryKey;
+}
+
+NTSTATUS
+FmmOpenServiceParametersKey (
     _In_ PDRIVER_OBJECT DriverObject,
-    _In_ PUNICODE_STRING RegistryPath
+    _In_ PUNICODE_STRING ServiceRegistryPath,
+    _Out_ PHANDLE ServiceParametersKey
     )
 /*++
 
 Routine Description:
 
-    This routine tries to read the filter DebugLevel parameter from
-    the registry.  This value will be found in the registry location
-    indicated by the RegistryPath passed in.
+    This routine opens the service parameters key, using the isolation-compliant
+    APIs when possible.
 
 Arguments:
 
@@ -320,66 +362,82 @@ Arguments:
 
     RegistryPath - The path key passed to the driver during DriverEntry.
 
+    ServiceParametersKey - Returns a handle to the service parameters subkey.
+
 Return Value:
 
-    None.
+    STATUS_SUCCESS if the function completes successfully.  Otherwise a valid
+    NTSTATUS code is returned.
 
 --*/
 {
-    OBJECT_ATTRIBUTES attributes;
-    OSVERSIONINFOW versionInfo;
-    HANDLE driverRegKey = NULL;
     NTSTATUS status;
-    ULONG resultLength;
-    UNICODE_STRING valueName;
-    UCHAR buffer[sizeof( KEY_VALUE_PARTIAL_INFORMATION ) + sizeof( LONG )];
-
-    Globals.DebugLevel = DEBUG_TRACE_ERROR;
-
-    RtlZeroMemory( &versionInfo, sizeof( versionInfo ) );
+    PFN_IoOpenDriverRegistryKey pIoOpenDriverRegistryKey;
+    UNICODE_STRING Subkey;
+    HANDLE ParametersKey = NULL;
+    HANDLE ServiceRegKey = NULL;
+    OBJECT_ATTRIBUTES Attributes;
 
     //
-    // Determine the OS version being run.
+    //  Open the parameters key to read values from the INF, using the API to
+    //  open the key if possible
     //
 
-    versionInfo.dwOSVersionInfoSize = sizeof( versionInfo );
+    pIoOpenDriverRegistryKey = FmmGetIoOpenDriverRegistryKey();
 
-    status = RtlGetVersion( &versionInfo );
+    if (pIoOpenDriverRegistryKey != NULL) {
 
-    if (!NT_SUCCESS( status )) {
+        //
+        //  Open the parameters key using the API
+        //
 
-        goto cleanup;
-    }
+        status = pIoOpenDriverRegistryKey( DriverObject,
+                                           DriverRegKeyParameters,
+                                           KEY_READ,
+                                           0,
+                                           &ParametersKey );
 
-    //
-    //  Open the desired registry key
-    //
+        if (!NT_SUCCESS( status )) {
+
+            goto cleanup;
+        }
+
+    } else {
 
-    if (versionInfo.dwBuildNumber >= 25952) {
         //
-        // Open the Parameters key for the service.
+        //  Open specified service root key
         //
 
-        status = IoOpenDriverRegistryKey( DriverObject,
-                                          DriverRegKeyParameters,
-                                          KEY_READ,
-                                          0,
-                                          &driverRegKey );
+        InitializeObjectAttributes( &Attributes,
+                                    ServiceRegistryPath,
+                                    OBJ_CASE_INSENSITIVE | OBJ_KERNEL_HANDLE,
+                                    NULL,
+                                    NULL );
+
+        status = ZwOpenKey( &ServiceRegKey,
+                            KEY_READ,
+                            &Attributes );
 
         if (!NT_SUCCESS( status )) {
 
             goto cleanup;
         }
-    } else {
-        InitializeObjectAttributes( &attributes,
-                                    RegistryPath,
+
+        //
+        //  Open the parameters key relative to service key path
+        //
+
+        RtlInitUnicodeString( &Subkey, L"Parameters" );
+
+        InitializeObjectAttributes( &Attributes,
+                                    &Subkey,
                                     OBJ_CASE_INSENSITIVE | OBJ_KERNEL_HANDLE,
-                                    NULL,
+                                    ServiceRegKey,
                                     NULL );
 
-        status = ZwOpenKey( &driverRegKey,
+        status = ZwOpenKey( &ParametersKey,
                             KEY_READ,
-                            &attributes );
+                            &Attributes );
 
         if (!NT_SUCCESS( status )) {
 
@@ -388,6 +446,71 @@ Return Value:
     }
 
     //
+    //  Return value to caller
+    //
+
+    *ServiceParametersKey = ParametersKey;
+
+cleanup:
+
+    if (ServiceRegKey != NULL) {
+
+        ZwClose( ServiceRegKey );
+    }
+
+    return status;
+
+}
+
+VOID
+FmmInitializeDebugLevel (
+    _In_ PDRIVER_OBJECT DriverObject,
+    _In_ PUNICODE_STRING RegistryPath
+    )
+/*++
+
+Routine Description:
+
+    This routine tries to read the filter DebugLevel parameter from
+    the registry.  This value will be found in the registry location
+    indicated by the RegistryPath passed in.
+
+Arguments:
+
+    DriverObject - Pointer to driver object created by the system to
+        represent this driver.
+
+    RegistryPath - The path key passed to the driver during DriverEntry.
+
+Return Value:
+
+    None.
+
+--*/
+{
+    HANDLE driverRegKey = NULL;
+    NTSTATUS status;
+    ULONG resultLength;
+    UNICODE_STRING valueName;
+    UCHAR buffer[sizeof( KEY_VALUE_PARTIAL_INFORMATION ) + sizeof( LONG )];
+
+    Globals.DebugLevel = DEBUG_TRACE_ERROR;
+
+    //
+    //  Open service parameters key to query values from.
+    //
+
+    status = FmmOpenServiceParametersKey( DriverObject,
+                                          RegistryPath,
+                                          &driverRegKey );
+
+    if (!NT_SUCCESS( status )) {
+
+        driverRegKey = NULL;
+        goto cleanup;
+    }
+
+    //
     // Read the DebugFlags value from the registry.
     //