IntelFsp2Pkg/Library/BaseFspCommonLib: Fix OVERRUN Coverity issue

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4200

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>
Signed-off-by: Ranbir Singh <rsingh@ventanamicro.com>
Acked-by: Pedro Falcato <pedro.falcato@gmail.com>
Reviewed-by: Chasel Chiu <chasel.chiu@intel.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/IntelFsp2Pkg/Library/BaseFspCommonLib/FspCommonLib.c b/IntelFsp2Pkg/Library/BaseFspCommonLib/FspCommonLib.c
index a22b0e7825..6f6a086111 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 0;

 }

 

 /**