CPP: Fix type logic.

Author: geoffw0

cpp/ql/src/Security/CWE/CWE-468/SuspiciousAddWithSizeof.ql

@@ -15,9 +15,9 @@ import IncorrectPointerScalingCommon
 
 private predicate isCharSzPtrExpr(Expr e) {
   exists (PointerType pt
-  | pt = e.getFullyConverted().getUnderlyingType()
-  | pt.getBaseType().getUnspecifiedType() instanceof CharType
-  or pt.getBaseType().getUnspecifiedType() instanceof VoidType)
+  | pt = e.getFullyConverted().getType().getUnspecifiedType()
+  | pt.getBaseType() instanceof CharType
+  or pt.getBaseType() instanceof VoidType)
 }
 
 from Expr sizeofExpr, Expr e

cpp/ql/test/query-tests/Security/CWE/CWE-468/semmle/SuspiciousAddWithSizeof/SuspiciousAddWithSizeof.expected

@@ -4,5 +4,4 @@
 | test.cpp:30:25:30:35 | sizeof(int) | Suspicious sizeof offset in a pointer arithmetic expression. The type of the pointer is int *. |
 | test.cpp:38:30:38:40 | sizeof(int) | Suspicious sizeof offset in a pointer arithmetic expression. The type of the pointer is int *. |
 | test.cpp:61:27:61:37 | sizeof(int) | Suspicious sizeof offset in a pointer arithmetic expression. The type of the pointer is int *. |
-| test.cpp:88:35:88:47 | sizeof(MyABC) | Suspicious sizeof offset in a pointer arithmetic expression. The type of the pointer is myChar *const. |
 | test.cpp:89:40:89:52 | sizeof(MyABC) | Suspicious sizeof offset in a pointer arithmetic expression. The type of the pointer is myInt *const. |

cpp/ql/test/query-tests/Security/CWE/CWE-468/semmle/SuspiciousAddWithSizeof/test.cpp

@@ -85,7 +85,7 @@ class MyTest8Class
     pairPtr((myChar *)malloc(sizeof(MyABC) * 2)),
     pairPtrInt((myInt *)malloc(sizeof(MyABC) * 2))
   {
-    myChar *secondPtr = pairPtr + sizeof(MyABC); // GOOD [FALSE POSITIVE]
+    myChar *secondPtr = pairPtr + sizeof(MyABC); // GOOD
     myInt *secondPtrInt = pairPtrInt + sizeof(MyABC); // BAD
   }