MdePkg: Fix overflow issue in BasePeCoffLib:

 PeCoffLoaderRelocateImage

The RelocDir->Size is a UINT32 value, and RelocDir->VirtualAddress is
also a UINT32 value. The current code does not check for overflow when
adding RelocDir->Size to RelocDir->VirtualAddress. This patch adds a
check to ensure that the addition does not overflow.

Signed-off-by: Doug Flick <dougflick@microsoft.com>
Authored-by: sriraamx gobichettipalayam <sri..@intel.com>

Author: Flickdm

MdePkg/Library/BasePeCoffLib/BasePeCoff.c

@@ -1054,7 +1054,7 @@ PeCoffLoaderRelocateImage (
     RelocDir = &Hdr.Te->DataDirectory[0];
   }
 
-  if ((RelocDir != NULL) && (RelocDir->Size > 0)) {
+  if ((RelocDir != NULL) && (RelocDir->Size > 0) && (RelocDir->Size - 1 < MAX_UINT32 - RelocDir->VirtualAddress)) {
     RelocBase    = (EFI_IMAGE_BASE_RELOCATION *)PeCoffLoaderImageAddress (ImageContext, RelocDir->VirtualAddress, TeStrippedOffset);
     RelocBaseEnd = (EFI_IMAGE_BASE_RELOCATION *)PeCoffLoaderImageAddress (
                                                   ImageContext,