Allow MaD barriers

This commit was done by Opus 4.5 with the following prompt:

In the commit 004d40e I have made it so that C# CodeQL queries which use sinks defined using data extensions (also known as "models-as-data"), which are accessed using `sinkNode(Node node, string kind)`, also use barriers defined using models-as-data, which are accessed using `barrierNode(Node node, string kind)`, with the same `kind` string. Please do the same for C++. If there are any complicated cases then list them at the end for me to do manually.

Author: owen-mc

cpp/ql/lib/semmle/code/cpp/dataflow/ExternalFlow.qll

@@ -249,6 +249,27 @@ predicate summaryModel(
   )
 }
 
+/**
+ * Holds if a barrier model exists for the given parameters.
+ */
+predicate barrierModel(
+  string namespace, string type, boolean subtypes, string name, string signature, string ext,
+  string output, string kind, string provenance, string model
+) {
+  MaD::barrierModel(namespace, type, subtypes, name, signature, ext, output, kind, provenance, model)
+}
+
+/**
+ * Holds if a barrier guard model exists for the given parameters.
+ */
+predicate barrierGuardModel(
+  string namespace, string type, boolean subtypes, string name, string signature, string ext,
+  string input, string acceptingvalue, string kind, string provenance, string model
+) {
+  MaD::barrierGuardModel(namespace, type, subtypes, name, signature, ext, input, acceptingvalue,
+    kind, provenance, model)
+}
+
 /** Provides a query predicate to check the CSV data for validation errors. */
 module CsvValidation {
   private string getInvalidModelInput() {
@@ -1028,6 +1049,17 @@ private module Cached {
       isSinkNode(n, kind, model) and n.asNode() = node
     )
   }
+
+  /**
+   * Holds if `node` is specified as a barrier with the given kind in a MaD flow
+   * model.
+   */
+  cached
+  predicate barrierNode(DataFlow::Node node, string kind, string model) {
+    exists(SourceSinkInterpretationInput::InterpretNode n |
+      isBarrierNode(n, kind, model) and n.asNode() = node
+    )
+  }
 }
 
 import Cached
@@ -1044,6 +1076,12 @@ predicate sourceNode(DataFlow::Node node, string kind) { sourceNode(node, kind,
  */
 predicate sinkNode(DataFlow::Node node, string kind) { sinkNode(node, kind, _) }
 
+/**
+ * Holds if `node` is specified as a barrier with the given kind in a MaD flow
+ * model.
+ */
+predicate barrierNode(DataFlow::Node node, string kind) { barrierNode(node, kind, _) }
+
 private predicate interpretSummary(
   Function f, string input, string output, string kind, string provenance, string model
 ) {

cpp/ql/lib/semmle/code/cpp/dataflow/internal/FlowSummaryImpl.qll

@@ -149,16 +149,27 @@ module SourceSinkInterpretationInput implements
   }
 
   predicate barrierElement(
-    Element n, string output, string kind, Public::Provenance provenance, string model
+    Element e, string output, string kind, Public::Provenance provenance, string model
   ) {
-    none()
+    exists(
+      string namespace, string type, boolean subtypes, string name, string signature, string ext
+    |
+      barrierModel(namespace, type, subtypes, name, signature, ext, output, kind, provenance, model) and
+      e = interpretElement(namespace, type, subtypes, name, signature, ext)
+    )
   }
 
   predicate barrierGuardElement(
-    Element n, string input, Public::AcceptingValue acceptingvalue, string kind,
+    Element e, string input, Public::AcceptingValue acceptingvalue, string kind,
     Public::Provenance provenance, string model
   ) {
-    none()
+    exists(
+      string namespace, string type, boolean subtypes, string name, string signature, string ext
+    |
+      barrierGuardModel(namespace, type, subtypes, name, signature, ext, input, acceptingvalue,
+        kind, provenance, model) and
+      e = interpretElement(namespace, type, subtypes, name, signature, ext)
+    )
   }
 
   private newtype TInterpretNode =

cpp/ql/src/Security/CWE/CWE-089/SqlTainted.ql

@@ -45,6 +45,9 @@ module SqlTaintedConfig implements DataFlow::ConfigSig {
 
   predicate isBarrier(DataFlow::Node node) {
     node.asExpr().getUnspecifiedType() instanceof IntegralType
+    or
+    // barrier defined using models-as-data
+    barrierNode(node, "sql-injection")
   }
 
   predicate isBarrierIn(DataFlow::Node node) {