Re: [PATCH v2 0/5] [CVE-2017-5753] Bounds Check Bypass issue in SMI handlers

[Laszlo Ersek <lersek@redhat.com>]

On 09/25/18 08:12, Hao Wu wrote:
> V2 changes:
> A. Rename the newly introduced BaseLib API to 'AsmLfence', and makes it
>    IA32/X64 specific.
> 
> B. Add brief comments before calls of the AsmLfence() to state the
>    purpose.
> 
> C. Refine the patch for Variable/RuntimeDxe driver and make the change
>    focus on the SMM code.
> 
> V1 history:
> The series aims to mitigate the Bounds Check Bypass (CVE-2017-5753) issues
> within SMI handlers.
> 
> A more detailed explanation of the purpose of the series is under the
> 'Bounds check bypass mitigation' section of the below link:
> https://software.intel.com/security-software-guidance/insights/host-firmware-speculative-execution-side-channel-mitigation
> 
> And the document at:
> https://software.intel.com/security-software-guidance/api-app/sites/default/files/337879-analyzing-potential-bounds-Check-bypass-vulnerabilities.pdf
> 
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Leif Lindholm <leif.lindholm@linaro.org>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Michael D Kinney <michael.d.kinney@intel.com>
> Cc: Liming Gao <liming.gao@intel.com>
> Cc: Star Zeng <star.zeng@intel.com>
> Cc: Eric Dong <eric.dong@intel.com>
> 
> Hao Wu (5):
>   MdePkg/BaseLib: Add new AsmLfence API
>   MdeModulePkg/FaultTolerantWrite:[CVE-2017-5753]Fix bounds check bypass
>   MdeModulePkg/SmmLockBox: [CVE-2017-5753] Fix bounds check bypass
>   MdeModulePkg/Variable: [CVE-2017-5753] Fix bounds check bypass
>   UefiCpuPkg/PiSmmCpuDxeSmm: [CVE-2017-5753] Fix bounds check bypass
> 
>  MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteSmm.c   |  7 ++++
>  MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteSmm.inf |  1 +
>  MdeModulePkg/Universal/LockBox/SmmLockBox/SmmLockBox.c                 | 10 ++++++
>  MdeModulePkg/Universal/Variable/RuntimeDxe/LoadFenceDxe.c              | 31 ++++++++++++++++
>  MdeModulePkg/Universal/Variable/RuntimeDxe/LoadFenceSmm.c              | 30 ++++++++++++++++
>  MdeModulePkg/Universal/Variable/RuntimeDxe/PrivilegePolymorphic.h      | 13 ++++++-
>  MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c                  |  6 ++++
>  MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf      |  1 +
>  MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c               | 18 ++++++++++
>  MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf             |  1 +
>  MdePkg/Include/Library/BaseLib.h                                       | 13 +++++++
>  MdePkg/Library/BaseLib/BaseLib.inf                                     |  2 ++
>  MdePkg/Library/BaseLib/Ia32/Lfence.nasm                                | 37 +++++++++++++++++++
>  MdePkg/Library/BaseLib/X64/Lfence.nasm                                 | 38 ++++++++++++++++++++
>  UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c                             |  5 +++
>  15 files changed, 212 insertions(+), 1 deletion(-)
>  create mode 100644 MdeModulePkg/Universal/Variable/RuntimeDxe/LoadFenceDxe.c
>  create mode 100644 MdeModulePkg/Universal/Variable/RuntimeDxe/LoadFenceSmm.c
>  create mode 100644 MdePkg/Library/BaseLib/Ia32/Lfence.nasm
>  create mode 100644 MdePkg/Library/BaseLib/X64/Lfence.nasm
> 

I regression-tested this series using:

(1) roughly the Linux guest steps from
<https://github.com/tianocore/tianocore.github.io/wiki/Testing-SMM-with-QEMU,-KVM-and-libvirt#tests-to-perform-in-the-installed-guest-fedora-26-guest>.


Those steps cover all of the SMM variable driver, the SMM FTW driver,
the SMM lockbox, and PiSmmCpuDxeSmm.

(2) For briefly checking the runtime (non-SMM) variable driver, I booted
Fedora guests on X64 OVMF and AARCH64 ArmVirtQemu, and invoked
"efibootmgr -v".

series
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>

Thanks,
Laszlo