Re: [edk2-devel] [PATCH 2/5] MdeModulePkg/SecurityLockAuditDebugLib: Add lib instance

["Laszlo Ersek" <lersek@redhat.com>]

On 07/22/19 06:02, Gao, Zhichao wrote:
> From: Bret Barkelew <Bret.Barkelew@microsoft.com>
> 
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2006
> 
> Add the instance of SecurityLockAuditLib. This instance
> has one interface SecurityLockReportEvent to log hardware
> and software security locks info.
> 
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Hao A Wu <hao.a.wu@intel.com>
> Cc: Ray Ni <ray.ni@intel.com>
> Cc: Star Zeng <star.zeng@intel.com>
> Cc: Liming gao <liming.gao@intel.com>
> Cc: Sean Brogan <sean.brogan@microsoft.com>
> Cc: Michael Turner <Michael.Turner@microsoft.com>
> Cc: Bret Barkelew <Bret.Barkelew@microsoft.com>
> Signed-off-by: Zhichao Gao <zhichao.gao@intel.com>
> ---
>  .../SecurityLockAuditDebugLib.c               | 53 +++++++++++++++++++
>  .../SecurityLockAuditDebugLib.inf             | 29 ++++++++++
>  2 files changed, 82 insertions(+)
>  create mode 100644 MdeModulePkg/Library/SecurityLockAuditDebugLib/SecurityLockAuditDebugLib.c
>  create mode 100644 MdeModulePkg/Library/SecurityLockAuditDebugLib/SecurityLockAuditDebugLib.inf
> 
> diff --git a/MdeModulePkg/Library/SecurityLockAuditDebugLib/SecurityLockAuditDebugLib.c b/MdeModulePkg/Library/SecurityLockAuditDebugLib/SecurityLockAuditDebugLib.c
> new file mode 100644
> index 0000000000..c1872bc023
> --- /dev/null
> +++ b/MdeModulePkg/Library/SecurityLockAuditDebugLib/SecurityLockAuditDebugLib.c
> @@ -0,0 +1,53 @@
> +/** @file
> +  This library implements the necessary functions
> +  to log hardware and software security locks for post-processing
> +
> +  Copyright (c) 2018, Microsoft Corporation
> +
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <Base.h>
> +#include <Library/SecurityLockAuditLib.h>
> +#include <Library/DebugLib.h>
> +
> +//
> +// Used to look up lock name from LOCK_TYPE enum
> +//
> +CHAR8* mLockName[] = {
> +  "SOFTWARE_LOCK",
> +  "HARDWARE_LOCK"
> +};
> +
> +
> +/**
> +  Function for security Lock event logging and reporting
> +
> +  @param[in] Module                   GUID of calling module
> +  @param[in] Function                 Name of calling function
> +  @param[in] LockEventText            Debug message explaining what is locked
> +  @param[in] LockType                 Enumerated lock type for differentiation
> +
> +**/
> +VOID
> +EFIAPI
> +SecurityLockReportEvent (
> +  IN GUID           *Module,
> +  IN CONST CHAR8    *Function,
> +  IN CONST CHAR8    *LockEventText,
> +  IN LOCK_TYPE      LockType
> +  )
> +{
> +  UINTN LockTypeIndex;
> +  UINTN LockNameCount;
> +
> +  LockTypeIndex = (UINTN)LockType;
> +  LockNameCount = sizeof (mLockName) / sizeof (mLockName[0]);
> +
> +  if (LockTypeIndex < LockNameCount) {
> +    DEBUG ((DEBUG_ERROR, "SecurityLock::LockType: %a, Module: %g, Function: %a, Output: %a\n", mLockName[LockTypeIndex], Module, Function, LockEventText));
> +  } else {
> +    DEBUG ((DEBUG_ERROR, "SecurityLock::LockType: %d, Module: %g, Function: %a, Output: %a\n", LockType, Module, Function, LockEventText));
> +  }
> +}

I disagree with this implementation. Security log messages are
important, but they are not necessarily errors. DEBUG_ERROR should be
used for errors, preferably for such that cannot be recovered from
(DEBUG_WARN is OK for recoverable errors).

If DEBUG_INFO is deemed too "quiet" for logging security events, then we
should introduce a new bit value for the debug bitmask, such as
DEBUG_SECURITY. We have a number of "special purpose" bits already:

- DEBUG_LOAD
- DEBUG_FS
- DEBUG_POOL
- DEBUG_PAGE
- DEBUG_DISPATCH
- etc

and I think we have room for DEBUG_SECURITY.

(1) And then, the log mask in this library instance should be

  DEBUG_SECURITY | DEBUG_INFO

I believe.

Thanks
Laszlo



> diff --git a/MdeModulePkg/Library/SecurityLockAuditDebugLib/SecurityLockAuditDebugLib.inf b/MdeModulePkg/Library/SecurityLockAuditDebugLib/SecurityLockAuditDebugLib.inf
> new file mode 100644
> index 0000000000..b641016087
> --- /dev/null
> +++ b/MdeModulePkg/Library/SecurityLockAuditDebugLib/SecurityLockAuditDebugLib.inf
> @@ -0,0 +1,29 @@
> +## @file
> +#
> +# Library that implements logging and reporting for security locks
> +# Using DebugLib
> +#
> +#
> +# Copyright (c) 2018, Microsoft Corporation
> +#
> +# SPDX-License-Identifier: BSD-2-Clause-Patent
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 0x00010005
> +  BASE_NAME                      = SecurityLockAuditDebugLib
> +  FILE_GUID                      = 459d0456-d6be-458e-9cc8-e9b21745f9aa
> +  MODULE_TYPE                    = BASE
> +  VERSION_STRING                 = 1.0
> +  LIBRARY_CLASS                  = SecurityLockAuditLib
> +
> +[Sources.common]
> +  SecurityLockAuditDebugLib.c
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +  MdeModulePkg/MdeModulePkg.dec
> +
> +[LibraryClasses]
> +  BaseLib
> +  DebugLib
>