Re: [edk2-devel] [PATCH 1/1] IntelFsp2Pkg/Library/BaseFspCommonLib: Fix OVERRUN Coverity issue

[Ranbir Singh <rsingh@ventanamicro.com>]

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Yes Chasel - please do so while merging, thanks!

On Tue, May 30, 2023 at 8:58 AM Chiu, Chasel <chasel.chiu@intel.com> wrote:

>
> That’s good suggestion Pedro!
> Ranbir, would you like me to modify your patch to "return 0" during
> merging?
>
> Thanks,
> Chasel
>
>
> > -----Original Message-----
> > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Pedro
> > Falcato
> > Sent: Friday, May 19, 2023 5:29 AM
> > To: devel@edk2.groups.io; rsingh@ventanamicro.com
> > Cc: Chiu, Chasel <chasel.chiu@intel.com>; Desimone, Nathaniel L
> > <nathaniel.l.desimone@intel.com>; Zeng, Star <star.zeng@intel.com>;
> Ranbir
> > Singh <Ranbir.Singh3@dell.com>
> > Subject: Re: [edk2-devel] [PATCH 1/1]
> IntelFsp2Pkg/Library/BaseFspCommonLib:
> > Fix OVERRUN Coverity issue
> >
> > On Thu, May 18, 2023 at 4:16 PM Ranbir Singh <rsingh@ventanamicro.com>
> > wrote:
> > >
> > > FspData->PerfIdx is getting increased for every call unconditionally
> > > in the function SetFspMeasurePoint and hence memory access can happen
> > > for out of bound FspData->PerfData[] array entries also.
> > >
> > > Example -
> > >    FspData->PerfData is an array of 32 UINT64 entries. Assume a call
> > >    is made to SetFspMeasurePoint function when the FspData->PerfIdx
> > >    last value is 31. It gets incremented to 32 at line 400.
> > >    Any subsequent call to SetFspMeasurePoint functions leads to
> > >    FspData->PerfData[32] getting accessed which is out of the PerfData
> > >    array as well as the FSP_GLOBAL_DATA structure boundary.
> > >
> > > Hence keep array access and index increment inside if block only and
> > > return invalid performance timestamp when PerfIdx is invalid.
> > >
> > > Cc: Chasel Chiu <chasel.chiu@intel.com>
> > > Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
> > > Cc: Star Zeng <star.zeng@intel.com>
> > > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4200
> > > Signed-off-by: Ranbir Singh <Ranbir.Singh3@Dell.com>
> > > Signed-off-by: Ranbir Singh <rsingh@ventanamicro.com>
> > > ---
> > >  IntelFsp2Pkg/Library/BaseFspCommonLib/FspCommonLib.c | 6 ++++--
> > >  1 file changed, 4 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/IntelFsp2Pkg/Library/BaseFspCommonLib/FspCommonLib.c
> > > b/IntelFsp2Pkg/Library/BaseFspCommonLib/FspCommonLib.c
> > > index a22b0e7825ad..cda2a7b2478e 100644
> > > --- a/IntelFsp2Pkg/Library/BaseFspCommonLib/FspCommonLib.c
> > > +++ b/IntelFsp2Pkg/Library/BaseFspCommonLib/FspCommonLib.c
> > > @@ -377,7 +377,8 @@ GetFspSiliconInitUpdDataPointer (
> > >
> > >    @param[in] Id       Measurement point ID.
> > >
> > > -  @return performance timestamp.
> > > +  @return performance timestamp if current PerfIdx is valid,
> > > +          else return 0 as invalid performance timestamp
> > >  **/
> > >  UINT64
> > >  EFIAPI
> > > @@ -395,9 +396,10 @@ SetFspMeasurePoint (
> > >    if (FspData->PerfIdx < sizeof (FspData->PerfData) / sizeof (FspData-
> > >PerfData[0])) {
> > >      FspData->PerfData[FspData->PerfIdx]                  = AsmReadTsc
> ();
> > >      ((UINT8 *)(&FspData->PerfData[FspData->PerfIdx]))[7] = Id;
> > > +    return FspData->PerfData[(FspData->PerfIdx)++];
> > >    }
> > >
> > > -  return FspData->PerfData[(FspData->PerfIdx)++];
> > > +  return (UINT64)0x0000000000000000;
> >
> > return 0;
> >
> > Works just as well. You also don't need a cast.
> >
> > https://godbolt.org/z/e5vvGcWWo
> >
> > --
> > Pedro
> >
> >
> > 
> >
>
>

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