MdeModulePkg/Universal/SecurityStubDxe/SecurityStub.c

/** @file
  This driver supports platform security service.
  
  Copyright (c) 2006 - 2007, Intel Corporation                                              
  All rights reserved. This program and the accompanying materials                          
  are licensed and made available under the terms and conditions of the BSD License         
  which accompanies this distribution.  The full text of the license may be found at        
  http://opensource.org/licenses/bsd-license.php                                            

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.             

**/


#include "SecurityStub.h"

//
// Handle for the Security Architectural Protocol instance produced by this driver
//
EFI_HANDLE                  mSecurityArchProtocolHandle = NULL;

//
// Security Architectural Protocol instance produced by this driver
//
EFI_SECURITY_ARCH_PROTOCOL  mSecurityStub = { 
  SecurityStubAuthenticateState 
};


/**
  The EFI_SECURITY_ARCH_PROTOCOL (SAP) is used to abstract platform-specific 
  policy from the DXE core response to an attempt to use a file that returns a 
  given status for the authentication check from the section extraction protocol.  

  The possible responses in a given SAP implementation may include locking 
  flash upon failure to authenticate, attestation logging for all signed drivers, 
  and other exception operations.  The File parameter allows for possible logging 
  within the SAP of the driver.

  If File is NULL, then EFI_INVALID_PARAMETER is returned.

  If the file specified by File with an authentication status specified by 
  AuthenticationStatus is safe for the DXE Core to use, then EFI_SUCCESS is returned.

  If the file specified by File with an authentication status specified by 
  AuthenticationStatus is not safe for the DXE Core to use under any circumstances, 
  then EFI_ACCESS_DENIED is returned.

  If the file specified by File with an authentication status specified by 
  AuthenticationStatus is not safe for the DXE Core to use right now, but it 
  might be possible to use it at a future time, then EFI_SECURITY_VIOLATION is 
  returned.

  @param  This             The EFI_SECURITY_ARCH_PROTOCOL instance.
  @param  AuthenticationStatus 
                           This is the authentication type returned from the Section
                           Extraction protocol. See the Section Extraction Protocol
                           Specification for details on this type.
  @param  File             This is a pointer to the device path of the file that is
                           being dispatched. This will optionally be used for logging.

  @retval EFI_SUCCESS           The file specified by File did authenticate, and the
                                platform policy dictates that the DXE Core may use File.
  @retval EFI_INVALID_PARAMETER Driver is NULL.
  @retval EFI_SECURITY_VIOLATION The file specified by File did not authenticate, and
                                the platform policy dictates that File should be placed
                                in the untrusted state. A file may be promoted from
                                the untrusted to the trusted state at a future time
                                with a call to the Trust() DXE Service.
  @retval EFI_ACCESS_DENIED     The file specified by File did not authenticate, and
                                the platform policy dictates that File should not be
                                used for any purpose.

**/
EFI_STATUS
EFIAPI
SecurityStubAuthenticateState (
  IN EFI_SECURITY_ARCH_PROTOCOL  *This,
  IN UINT32                      AuthenticationStatus,
  IN EFI_DEVICE_PATH_PROTOCOL    *File
  )
{
  if (File == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  return EFI_SUCCESS;
}


/**
  The user Entry Point for DXE driver. The user code starts with this function
  as the real entry point for the image goes into a library that calls this 
  function.

  @param[in] ImageHandle    The firmware allocated handle for the EFI image.  
  @param[in] SystemTable    A pointer to the EFI System Table.
  
  @retval EFI_SUCCESS       The entry point is executed successfully.
  @retval other             Some error occurs when executing this entry point.

**/
EFI_STATUS
EFIAPI
SecurityStubInitialize (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS  Status;

  //
  // Make sure the Security Architectural Protocol is not already installed in the system
  //
  ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiSecurityArchProtocolGuid);

  //
  // Install the Security Architectural Protocol onto a new handle
  //
  Status = gBS->InstallMultipleProtocolInterfaces (
                  &mSecurityArchProtocolHandle,
                  &gEfiSecurityArchProtocolGuid,
                  &mSecurityStub,
                  NULL
                  );
  ASSERT_EFI_ERROR (Status);

  return Status;
}