C++: Remove cpp/invalid-pointer-deref results duplicating ones with smaller k

Author: jketema

cpp/ql/src/experimental/Security/CWE/CWE-193/InvalidPointerDeref.ql

@@ -377,15 +377,19 @@ predicate hasFlowPath(
 }
 
 from
-  MergedPathNode source, MergedPathNode sink, int k2, int k3, string kstr,
-  InvalidPointerToDerefFlow::PathNode source3, PointerArithmeticInstruction pai, string operation,
-  Expr offset, DataFlow::Node n
+  MergedPathNode source, MergedPathNode sink, int k, string kstr, PointerArithmeticInstruction pai,
+  string operation, Expr offset, DataFlow::Node n
 where
-  hasFlowPath(source, sink, source3, pai, operation, k3) and
-  invalidPointerToDerefSource(pai, source3.getNode(), k2) and
+  k =
+    min(int k2, int k3, InvalidPointerToDerefFlow::PathNode source3 |
+      hasFlowPath(source, sink, source3, pai, operation, k3) and
+      invalidPointerToDerefSource(pai, source3.getNode(), k2)
+    |
+       k2 + k3
+    ) and
   offset = pai.getRight().getUnconvertedResultExpression() and
   n = source.asPathNode1().getNode() and
-  if (k2 + k3) = 0 then kstr = "" else kstr = " + " + (k2 + k3)
+  if k = 0 then kstr = "" else kstr = " + " + k
 select sink, source, sink,
   "This " + operation + " might be out of bounds, as the pointer might be equal to $@ + $@" + kstr +
     ".", n, n.toString(), offset, offset.toString()

cpp/ql/test/experimental/query-tests/Security/CWE/CWE-193/pointer-deref/InvalidPointerDeref.expected

@@ -1128,5 +1128,4 @@ subpaths
 | test.cpp:358:14:358:26 | Load: * ... | test.cpp:355:14:355:27 | new[] | test.cpp:358:14:358:26 | Load: * ... | This read might be out of bounds, as the pointer might be equal to $@ + $@ + 1. | test.cpp:355:14:355:27 | new[] | new[] | test.cpp:356:20:356:23 | size | size |
 | test.cpp:359:14:359:32 | Load: * ... | test.cpp:355:14:355:27 | new[] | test.cpp:359:14:359:32 | Load: * ... | This read might be out of bounds, as the pointer might be equal to $@ + $@ + 2. | test.cpp:355:14:355:27 | new[] | new[] | test.cpp:356:20:356:23 | size | size |
 | test.cpp:372:15:372:16 | Load: * ... | test.cpp:363:14:363:27 | new[] | test.cpp:372:15:372:16 | Load: * ... | This read might be out of bounds, as the pointer might be equal to $@ + $@. | test.cpp:363:14:363:27 | new[] | new[] | test.cpp:365:19:365:22 | size | size |
-| test.cpp:384:13:384:16 | Load: * ... | test.cpp:377:14:377:27 | new[] | test.cpp:384:13:384:16 | Load: * ... | This read might be out of bounds, as the pointer might be equal to $@ + $@ + 1. | test.cpp:377:14:377:27 | new[] | new[] | test.cpp:378:20:378:23 | size | size |
 | test.cpp:384:13:384:16 | Load: * ... | test.cpp:377:14:377:27 | new[] | test.cpp:384:13:384:16 | Load: * ... | This read might be out of bounds, as the pointer might be equal to $@ + $@. | test.cpp:377:14:377:27 | new[] | new[] | test.cpp:378:20:378:23 | size | size |