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

["Chiu, Chasel" <chasel.chiu@intel.com>]

This fix looks good to me! Thanks Ranbir!
Reviewed-by: Chasel Chiu <chasel.chiu@intel.com>


> -----Original Message-----
> From: Ranbir Singh <rsingh@ventanamicro.com>
> Sent: Wednesday, May 17, 2023 11:29 PM
> To: devel@edk2.groups.io
> 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: [PATCH 1/1] IntelFsp2Pkg/Library/BaseFspCommonLib: Fix OVERRUN
> Coverity issue
> 
> 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; }
> /**--
> 2.34.1