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UefiCpuPkg: Move MigrateGdt from DiscoverMemory to TempRamDone. (CVE-2019-11098)

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REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1614
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3160

The GDT still in flash with commit 60b12e69fb
after TempRamDone

So move the action to TempRamDone event to avoid reading GDT from flash.

Signed-off-by: Guomin Jiang <guomin.jiang@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Debkumar De <debkumar.de@intel.com>
Cc: Harry Han <harry.han@intel.com>
Cc: Catharine West <catharine.west@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
This commit is contained in:
Guomin Jiang
2021-01-13 18:08:09 +08:00
committed by mergify[bot]
parent e806bb29cf
commit f6ec1dd34f
5 changed files with 46 additions and 46 deletions
Download Patch File Download Diff File Expand all files Collapse all files

45
UefiCpuPkg/SecCore/SecMain.c
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@@ -35,6 +35,43 @@ EFI_PEI_PPI_DESCRIPTOR mPeiSecPlatformInformationPpi[] = {
}
};
/**
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
MigrateGdt (
VOID
)
{
EFI_STATUS Status;
UINTN GdtBufferSize;
IA32_DESCRIPTOR Gdtr;
VOID *GdtBuffer;
AsmReadGdtr ((IA32_DESCRIPTOR *) &Gdtr);
GdtBufferSize = sizeof (IA32_SEGMENT_DESCRIPTOR) -1 + Gdtr.Limit + 1;
Status = PeiServicesAllocatePool (
GdtBufferSize,
&GdtBuffer
);
ASSERT (GdtBuffer != NULL);
if (EFI_ERROR (Status)) {
return EFI_OUT_OF_RESOURCES;
}
GdtBuffer = ALIGN_POINTER (GdtBuffer, sizeof (IA32_SEGMENT_DESCRIPTOR));
CopyMem (GdtBuffer, (VOID *) Gdtr.Base, Gdtr.Limit + 1);
Gdtr.Base = (UINTN) GdtBuffer;
AsmWriteGdtr (&Gdtr);
return EFI_SUCCESS;
}
//
// These are IDT entries pointing to 10:FFFFFFE4h.
//
@@ -409,6 +446,14 @@ SecTemporaryRamDone (
//
State = SaveAndDisableInterrupts ();
//
// Migrate GDT before NEM near down
//
if (PcdGetBool (PcdMigrateTemporaryRamFirmwareVolumes)) {
Status = MigrateGdt ();
ASSERT_EFI_ERROR (Status);
}
//
// Disable Temporary RAM after Stack and Heap have been migrated at this point.
//