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

["Wu, Hao A" <hao.a.wu@intel.com>]

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Laszlo
> Ersek
> Sent: Wednesday, September 26, 2018 4:57 AM
> To: Wu, Hao A; edk2-devel@lists.01.org
> Cc: Kinney, Michael D; Zeng, Star; Yao, Jiewen; Dong, Eric; Gao, Liming
> Subject: Re: [edk2] [PATCH v2 0/5] [CVE-2017-5753] Bounds Check Bypass issue
> in SMI handlers
> 
> 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.

Hi Laszlo,

Really appreciate the help for the regression tests.

I will document the those regression tests (also with the details) within
the BZ trackers:
https://bugzilla.tianocore.org/show_bug.cgi?id=1193
https://bugzilla.tianocore.org/show_bug.cgi?id=1194

Best Regards,
Hao Wu

> 
> Thanks
> Laszlo
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