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

[Ranbir Singh <rsingh@ventanamicro.com>]

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