[edk2-devel] [PATCH v2 2/9] UefiCpuPkg/CpuMpPei: Add GDT and IDT migration support (CVE-2019-11098)
Laszlo Ersek
lersek at redhat.com
Fri Jul 3 14:33:55 UTC 2020
On 07/03/20 15:57, Laszlo Ersek wrote:
> On 07/02/20 07:15, Guomin Jiang wrote:
>> From: Michael Kubacki <michael.a.kubacki at intel.com>
>>
>> REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1614
>>
>> Moves the GDT and IDT to permanent memory in a memory discovered
>> callback. This is done to ensure the GDT and IDT authenticated in
>> pre-memory is not fetched from outside a verified location after
>> the permanent memory transition.
>>
>> Cc: Eric Dong <eric.dong at intel.com>
>> Cc: Ray Ni <ray.ni at intel.com>
>> Cc: Laszlo Ersek <lersek at redhat.com>
>> Cc: Rahul Kumar <rahul1.kumar at intel.com>
>> Signed-off-by: Michael Kubacki <michael.a.kubacki at intel.com>
>> ---
>> UefiCpuPkg/CpuMpPei/CpuMpPei.c | 40 ++++++++++++++++++-
>> UefiCpuPkg/CpuMpPei/CpuMpPei.h | 13 ++++++
>> UefiCpuPkg/CpuMpPei/CpuPaging.c | 14 +++++--
>> .../Ia32/ArchExceptionHandler.c | 4 +-
>> .../SecPeiCpuException.c | 2 +-
>> 5 files changed, 65 insertions(+), 8 deletions(-)
>>
>> diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.c b/UefiCpuPkg/CpuMpPei/CpuMpPei.c
>> index 07ccbe7c6a91..2d6f1bc98851 100644
>> --- a/UefiCpuPkg/CpuMpPei/CpuMpPei.c
>> +++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.c
>> @@ -429,6 +429,44 @@ GetGdtr (
>> AsmReadGdtr ((IA32_DESCRIPTOR *)Buffer);
>> }
>>
>> +/**
>> + Migrates the Global Descriptor Table (GDT) to permanent memory.
>> +
>> + @retval EFI_SUCCESS The GDT was migrated successfully.
>> + @retval EFI_OUT_OF_RESOURCES The GDT could not be migrated due to lack of available memory.
>> +
>> +**/
>> +EFI_STATUS
>> +EFIAPI
>> +MigrateGdt (
>> + VOID
>> + )
>> +{
>> + EFI_STATUS Status;
>> + UINTN GdtBufferSize;
>> + IA32_DESCRIPTOR Gdtr;
>> + UINT8 *GdtBuffer;
>> +
>> + AsmReadGdtr ((IA32_DESCRIPTOR *) &Gdtr);
>> + GdtBufferSize = sizeof (IA32_TSS_DESCRIPTOR) + Gdtr.Limit + 1;
>> +
>> + Status = PeiServicesAllocatePool (
>> + GdtBufferSize,
>> + (VOID **) &GdtBuffer
>> + );
>> + ASSERT (GdtBuffer != NULL);
>> + if (EFI_ERROR (Status)) {
>> + return EFI_OUT_OF_RESOURCES;
>> + }
>> +
>> + GdtBuffer = ALIGN_POINTER (GdtBuffer, sizeof (IA32_TSS_DESCRIPTOR));
>> + CopyMem ((VOID *) (UINTN) GdtBuffer, (VOID *) Gdtr.Base, Gdtr.Limit + 1);
>> + Gdtr.Base = (UINT32)(UINTN) GdtBuffer;
>> + AsmWriteGdtr (&Gdtr);
>> +
>> + return EFI_SUCCESS;
>> +}
>> +
>> /**
>> Initializes CPU exceptions handlers for the sake of stack switch requirement.
>>
>> @@ -644,7 +682,7 @@ InitializeCpuMpWorker (
>> &gEfiVectorHandoffInfoPpiGuid,
>> 0,
>> NULL,
>> - (VOID **)&VectorHandoffInfoPpi
>> + (VOID **) &VectorHandoffInfoPpi
>> );
>> if (Status == EFI_SUCCESS) {
>> VectorInfo = VectorHandoffInfoPpi->Info;
>> diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.h b/UefiCpuPkg/CpuMpPei/CpuMpPei.h
>> index 7d5c527d6006..5dc956409594 100644
>> --- a/UefiCpuPkg/CpuMpPei/CpuMpPei.h
>> +++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.h
>> @@ -397,6 +397,19 @@ SecPlatformInformation2 (
>> OUT EFI_SEC_PLATFORM_INFORMATION_RECORD2 *PlatformInformationRecord2
>> );
>>
>> +/**
>> + Migrates the Global Descriptor Table (GDT) to permanent memory.
>> +
>> + @retval EFI_SUCCESS The GDT was migrated successfully.
>> + @retval EFI_OUT_OF_RESOURCES The GDT could not be migrated due to lack of available memory.
>> +
>> +**/
>> +EFI_STATUS
>> +EFIAPI
>> +MigrateGdt (
>> + VOID
>> + );
>> +
>> /**
>> Initializes MP and exceptions handlers.
>>
>> diff --git a/UefiCpuPkg/CpuMpPei/CpuPaging.c b/UefiCpuPkg/CpuMpPei/CpuPaging.c
>> index a462e7ee1e38..d0cbebf70bbf 100644
>> --- a/UefiCpuPkg/CpuMpPei/CpuPaging.c
>> +++ b/UefiCpuPkg/CpuMpPei/CpuPaging.c
>> @@ -152,7 +152,7 @@ GetPhysicalAddressWidth (
>> Get the type of top level page table.
>>
>> @retval Page512G PML4 paging.
>> - @retval Page1G PAE paing.
>> + @retval Page1G PAE paging.
>>
>> **/
>> PAGE_ATTRIBUTE
>> @@ -582,7 +582,7 @@ SetupStackGuardPage (
>> }
>>
>> /**
>> - Enabl/setup stack guard for each processor if PcdCpuStackGuard is set to TRUE.
>> + Enable/setup stack guard for each processor if PcdCpuStackGuard is set to TRUE.
>>
>> Doing this in the memory-discovered callback is to make sure the Stack Guard
>> feature to cover as most PEI code as possible.
>> @@ -602,8 +602,14 @@ MemoryDiscoveredPpiNotifyCallback (
>> IN VOID *Ppi
>> )
>> {
>> - EFI_STATUS Status;
>> - BOOLEAN InitStackGuard;
>> + EFI_STATUS Status;
>> + BOOLEAN InitStackGuard;
>> + BOOLEAN InterruptState;
>> +
>> + InterruptState = SaveAndDisableInterrupts ();
>> + Status = MigrateGdt ();
>> + ASSERT_EFI_ERROR (Status);
>> + SetInterruptState (InterruptState);
>>
>> //
>> // Paging must be setup first. Otherwise the exception TSS setup during MP
>
> (12) The GDT migration should be made dependent on
> "PcdMigrateTemporaryRamFirmwareVolumes", shouldn't it?
... Or is this *another* preexistent bug that we should fix regardless
of the "temporary RAM evacuation" feature?
I mean, considering current master, once we switch to permanent PEI RAM,
do we still rely on a GDT that lives in temp RAM?
If that's the case, then we should even split this series into two
series. The first series should fix the other issues first -- typos,
IN/OUT mistakes, this GDT problem, and the S3 shadowing bug in the DXE
IPL PEIM.
Once all that is done, we can introduce
"PcdMigrateTemporaryRamFirmwareVolumes", and the dependent new feature.
Thanks
Laszlo
>> diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c
>> index 1aafb7dac139..903449e0daa9 100644
>> --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c
>> +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c
>> @@ -18,8 +18,8 @@
>> **/
>> VOID
>> ArchUpdateIdtEntry (
>> - IN IA32_IDT_GATE_DESCRIPTOR *IdtEntry,
>> - IN UINTN InterruptHandler
>> + OUT IA32_IDT_GATE_DESCRIPTOR *IdtEntry,
>> + IN UINTN InterruptHandler
>> )
>> {
>> IdtEntry->Bits.OffsetLow = (UINT16)(UINTN)InterruptHandler;
>> diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c
>> index 20148db74cf8..d4ae153c5742 100644
>> --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c
>> +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c
>> @@ -87,7 +87,7 @@ InitializeCpuExceptionHandlers (
>> IdtEntryCount = (IdtDescriptor.Limit + 1) / sizeof (IA32_IDT_GATE_DESCRIPTOR);
>> if (IdtEntryCount > CPU_EXCEPTION_NUM) {
>> //
>> - // CPU exeption library only setup CPU_EXCEPTION_NUM exception handler at most
>> + // CPU exception library only setup CPU_EXCEPTION_NUM exception handler at most
>> //
>> IdtEntryCount = CPU_EXCEPTION_NUM;
>> }
>>
>
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