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

[Laszlo Ersek <lersek@redhat.com>]

On 09/25/18 22:51, Laszlo Ersek wrote:
> 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>

It's been a long day. I meant to describe another detail of the test
environment:

Because of the regression reported at
<https://bugzilla.tianocore.org/show_bug.cgi?id=1207>, OVMF is currently
unbootable. Therefore I first applied my fix from
<https://bugzilla.tianocore.org/show_bug.cgi?id=1207#c2> on top of
current master (3cb0a311cb7e). I applied this series of yours for
regression testing on top of my fix.

Thanks
Laszlo