Merge pull request #18269 from hvitved/csharp/dataflow-reflection-call

C#: Remove false-positive reflection calls in dataflow

Author: hvitved

csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowDispatch.qll

@@ -424,7 +424,11 @@ class NonDelegateDataFlowCall extends DataFlowCall, TNonDelegateCall {
   Callable getATarget(boolean static) {
     result = dc.getADynamicTarget().getUnboundDeclaration() and static = false
     or
-    result = dc.getAStaticTarget().getUnboundDeclaration() and static = true
+    result = dc.getAStaticTarget().getUnboundDeclaration() and
+    static = true and
+    // In reflection calls, _all_ methods with matching names and arities are considered
+    // static targets, so we need to exclude them
+    not dc.isReflection()
   }
 
   override ControlFlow::Nodes::ElementNode getControlFlowNode() { result = cfn }

csharp/ql/lib/semmle/code/csharp/dispatch/Dispatch.qll

@@ -52,7 +52,21 @@ class DispatchCall extends Internal::TDispatchCall {
   }
 
   /** Holds if this call uses reflection. */
-  predicate isReflection() { this instanceof Internal::TDispatchReflectionCall }
+  predicate isReflection() {
+    this instanceof Internal::TDispatchReflectionCall
+    or
+    this instanceof Internal::TDispatchDynamicElementAccess
+    or
+    this instanceof Internal::TDispatchDynamicMemberAccess
+    or
+    this instanceof Internal::TDispatchDynamicMethodCall
+    or
+    this instanceof Internal::TDispatchDynamicOperatorCall
+    or
+    this instanceof Internal::TDispatchDynamicEventAccess
+    or
+    this instanceof Internal::TDispatchDynamicObjectCreation
+  }
 }
 
 /** Internal implementation details. */