K8:

1) Fix the bug the assert conditions. || should be &&.
2) Add in code path and check-for-null-pointer to do error handling.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@7308 6f19259b-4bc3-4df7-8a09-765794883524

MdeModulePkg/Universal/HiiDatabaseDxe/String.c

@@ -124,7 +124,7 @@ ConvertToUnicodeText (
   ASSERT (StringSrc != NULL && BufferSize != NULL);
 
   StringSize = AsciiStrSize (StringSrc) * 2;
-  if (*BufferSize < StringSize) {
+  if (*BufferSize < StringSize || StringDest == NULL) {
     *BufferSize = StringSize;
     return EFI_BUFFER_TOO_SMALL;
   }