CPP: Exclude placement new.

Author: geoffw0

cpp/ql/src/jsf/4.10 Classes/AV Rule 79.ql

@@ -125,7 +125,21 @@ class Resource extends MemberVariable {
 
   private Assignment getANew() {
     result.getLValue() = this.getAnAccess() and
-    (result.getRValue() instanceof NewExpr or result.getRValue() instanceof NewArrayExpr) and
+    (
+      (
+        result.getRValue() instanceof NewExpr and
+
+        // exclude placement new and custom overloads as they
+        // may not conform to assumptions
+        not result.getRValue().(NewExpr).getAllocatorCall().getTarget().getNumberOfParameters() > 1
+      ) or (
+        result.getRValue() instanceof NewArrayExpr and
+
+        // exclude placement new and custom overloads as they
+        // may not conform to assumptions
+        not result.getRValue().(NewArrayExpr).getAllocatorCall().getTarget().getNumberOfParameters() > 1
+      )
+    ) and
     this.inSameClass(result)
   }
 

cpp/ql/test/query-tests/jsf/4.10 Classes/AV Rule 79/AV Rule 79.expected

@@ -12,7 +12,5 @@
 | ListDelete.cpp:21:3:21:21 | ... = ... | Resource first is acquired by class MyThingColection but not released anywhere in this class. |
 | NoDestructor.cpp:23:3:23:20 | ... = ... | Resource n is acquired by class MyClass5 but not released anywhere in this class. |
 | PlacementNew.cpp:36:3:36:36 | ... = ... | Resource p1 is acquired by class MyTestForPlacementNew but not released anywhere in this class. |
-| PlacementNew.cpp:37:3:37:51 | ... = ... | Resource p2 is acquired by class MyTestForPlacementNew but not released anywhere in this class. |
-| PlacementNew.cpp:38:3:38:49 | ... = ... | Resource p3 is acquired by class MyTestForPlacementNew but not released anywhere in this class. |
 | SelfRegistering.cpp:25:3:25:24 | ... = ... | Resource side is acquired by class MyOwner but not released anywhere in this class. |
 | Variants.cpp:23:3:23:13 | ... = ... | Resource f is acquired by class MyClass4 but not released anywhere in this class. |

cpp/ql/test/query-tests/jsf/4.10 Classes/AV Rule 79/PlacementNew.cpp

@@ -34,8 +34,8 @@ class MyTestForPlacementNew
 		void *buffer_ptr = buffer;
 
 		p1 = new MyClassForPlacementNew(1); // BAD: not released
-		p2 = new (std::nothrow) MyClassForPlacementNew(2); // BAD: not released
-		p3 = new (buffer_ptr) MyClassForPlacementNew(3); // GOOD: placement new, not an allocation [FALSE POSITIVE]
+		p2 = new (std::nothrow) MyClassForPlacementNew(2); // BAD: not released [NOT DETECTED]
+		p3 = new (buffer_ptr) MyClassForPlacementNew(3); // GOOD: placement new, not an allocation
 	}
 
 	~MyTestForPlacementNew()