> -----Original Message-----
> From: Ni, Ray
> Sent: Wednesday, June 26, 2019 9:58 AM
> To: Dong, Eric <eric.d...@intel.com>; Gao, Zhichao
> <zhichao....@intel.com>; devel@edk2.groups.io
> Cc: Laszlo Ersek <ler...@redhat.com>; Gao, Liming <liming....@intel.com>
> Subject: RE: [PATCH V2] UefiCpuPkg/MpInitLib: MicrocodeDetect: Ensure
> checked range is valid
>
> > > @@ -170,6 +170,7 @@ MicrocodeDetect (
> > > /// Check overflow and whether TotalSize is aligned with 4 bytes.
> > > ///
> > > if ( ((UINTN)MicrocodeEntryPoint + TotalSize) > MicrocodeEnd ||
> > > + ((UINTN)MicrocodeEntryPoint + TotalSize) < (UINTN)
> > > + CpuMpData->MicrocodePatchAddress ||
>
> How about below check?
> First comparison hits when the sum of MicrocodeEntryPoint and TotalSize
> overflows.
> Second comparison hits when the sum crosses the boundary of the whole
> microcode buffer boundary If (((UINTN) MicrocodeEntryPoint > MAX_UINTN
> - TotalSize) || ((UINTN)MicrocodeEntryPoint + TotalSize) > MicrocodeEnd)
Your advice is better. It avoid the sum of MicrocodeEntryPoint and TotalSize
bigger than CpuMpData->MicrocodePatchAddress and less than MicrocodeEntryPoint.
I would update it with your comments.
Thanks,
Zhichao
>
>
> > > (TotalSize & 0x3) != 0
> > > ) {
> > > MicrocodeEntryPoint = (CPU_MICROCODE_HEADER *) (((UINTN)
> > > MicrocodeEntryPoint) + SIZE_1KB);
> > > --
> > > 2.21.0.windows.1
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