ObReferenceObjectByHandle

The ObReferenceObjectByHandle routine provides access validation on the object handle, and, if access can be granted, returns the corresponding pointer to the object’s body.

NTSTATUS 
  ObReferenceObjectByHandle(
    IN HANDLE  Handle,
    IN ACCESS_MASK  DesiredAccess,
    IN POBJECT_TYPE  ObjectType  OPTIONAL,
    IN KPROCESSOR_MODE  AccessMode,
    OUT PVOID  *Object,
    OUT POBJECT_HANDLE_INFORMATION  HandleInformation  OPTIONAL
    );

Parameters

Handle

Specifies an open handle for an object.

DesiredAccess

Specifies the requested types of access to the object. The interpretation of this field is dependent on the object type.

ObjectType

Pointer to the object type. ObjectType can be either *IoFileObjectType or *ExEventObjectType. This parameter can also be NULL if AccessMode is KernelMode.

AccessMode

Specifies the access mode to use for the access check. It must be either UserMode or KernelMode. Lower-level drivers should specify KernelMode.

Object

Pointer to a variable that receives a pointer to the object’s body.

HandleInformation

Drivers set this to NULL.

Return Value

ObReferenceObjectByHandle returns an NTSTATUS value. The possible return values include:

STATUS_SUCCESS
STATUS_OBJECT_TYPE_MISMATCH
STATUS_ACCESS_DENIED
STATUS_INVALID_HANDLE

Headers

Declared in wdm.h and ntddk.h. Include wdm.h or ntddk.h.

Comments

A pointer to the object body is retrieved from the object table entry and returned to the caller by means of the Object parameter.

If the AccessMode parameter is KernelMode, the requested access is always allowed. If AccessMode is UserMode, the requested access is compared to the granted access for the object. Only highest-level drivers can safely specify UserMode for the input AccessMode.

If the call succeeds, a pointer to the object body is returned to the caller and the pointer reference count is incremented. Incrementing this count prevents the object from being deleted while the pointer is being referenced. The caller must decrement the reference count with ObDereferenceObject as soon as it is done with the object.

Callers of ObReferenceObjectByHandle must be running at IRQL = PASSIVE_LEVEL.

See Also

ObDereferenceObject, ObReferenceObject, ObReferenceObjectByPointer