Merge pull request #5554 from asgerf/js/non-recursive-propref

Approved by esbena

javascript/ql/src/semmle/javascript/NodeJS.qll

@@ -202,6 +202,42 @@ private class RequireVariable extends Variable {
  */
 private predicate moduleInFile(Module m, File f) { m.getFile() = f }
 
+private predicate isModuleModule(DataFlow::Node nd) {
+  exists(ImportDeclaration imp |
+    imp.getImportedPath().getValue() = "module" and
+    nd =
+      [
+        DataFlow::destructuredModuleImportNode(imp),
+        DataFlow::valueNode(imp.getASpecifier().(ImportNamespaceSpecifier))
+      ]
+  )
+  or
+  isModuleModule(nd.getAPredecessor())
+}
+
+private predicate isCreateRequire(DataFlow::Node nd) {
+  exists(PropAccess prop |
+    isModuleModule(prop.getBase().flow()) and
+    prop.getPropertyName() = "createRequire" and
+    nd = prop.flow()
+  )
+  or
+  exists(PropertyPattern prop |
+    isModuleModule(prop.getObjectPattern().flow()) and
+    prop.getName() = "createRequire" and
+    nd = prop.getValuePattern().flow()
+  )
+  or
+  exists(ImportDeclaration decl, NamedImportSpecifier spec |
+    decl.getImportedPath().getValue() = "module" and
+    spec = decl.getASpecifier() and
+    spec.getImportedName() = "createRequire" and
+    nd = spec.flow()
+  )
+  or
+  isCreateRequire(nd.getAPredecessor())
+}
+
 /**
  * Holds if `nd` may refer to `require`, either directly or modulo local data flow.
  */
@@ -215,16 +251,11 @@ private predicate isRequire(DataFlow::Node nd) {
   or
   // `import { createRequire } from 'module';`.
   // specialized to ES2015 modules to avoid recursion in the `DataFlow::moduleImport()` predicate and to avoid
-  // negative recursion between `Import.getImportedModuleNode()` and `Import.getImportedModule()`.
-  exists(ImportDeclaration imp, DataFlow::SourceNode baseObj |
-    imp.getImportedPath().getValue() = "module"
-  |
-    baseObj =
-      [
-        DataFlow::destructuredModuleImportNode(imp),
-        DataFlow::valueNode(imp.getASpecifier().(ImportNamespaceSpecifier))
-      ] and
-    nd = baseObj.getAPropertyRead("createRequire").getACall()
+  // negative recursion between `Import.getImportedModuleNode()` and `Import.getImportedModule()`, and
+  // to avoid depending on `SourceNode` as this would make `SourceNode::Range` recursive.
+  exists(CallExpr call |
+    isCreateRequire(call.getCallee().flow()) and
+    nd = call.flow()
   )
 }
 

javascript/ql/src/semmle/javascript/dataflow/DataFlow.qll

@@ -492,6 +492,7 @@ module DataFlow {
      * Gets the data flow node corresponding to the base object
      * whose property is read from or written to.
      */
+    cached
     abstract Node getBase();
 
     /**
@@ -595,7 +596,10 @@ module DataFlow {
 
     PropLValueAsPropWrite() { astNode instanceof LValue }
 
-    override Node getBase() { result = valueNode(astNode.getBase()) }
+    override Node getBase() {
+      result = valueNode(astNode.getBase()) and
+      Stages::DataFlowStage::ref()
+    }
 
     override Expr getPropertyNameExpr() { result = astNode.getPropertyNameExpr() }
 
@@ -724,7 +728,7 @@ module DataFlow {
     override ParameterField prop;
 
     override Node getBase() {
-      result = thisNode(prop.getDeclaringClass().getConstructor().getBody())
+      thisNode(result, prop.getDeclaringClass().getConstructor().getBody())
     }
 
     override Expr getPropertyNameExpr() {
@@ -758,7 +762,7 @@ module DataFlow {
     }
 
     override Node getBase() {
-      result = thisNode(prop.getDeclaringClass().getConstructor().getBody())
+      thisNode(result, prop.getDeclaringClass().getConstructor().getBody())
     }
 
     override Expr getPropertyNameExpr() { result = prop.getNameExpr() }

javascript/ql/src/semmle/javascript/dataflow/Sources.qll

@@ -34,7 +34,11 @@ private import semmle.javascript.internal.CachedStages
  * ```
  */
 class SourceNode extends DataFlow::Node {
-  SourceNode() { this instanceof SourceNode::Range }
+  SourceNode() {
+    this instanceof SourceNode::Range
+    or
+    none() and this instanceof SourceNode::Internal::RecursionGuard
+  }
 
   /**
    * Holds if this node flows into `sink` in zero or more local (that is,
@@ -329,6 +333,12 @@ module SourceNode {
       DataFlow::functionReturnNode(this, _)
     }
   }
+
+  /** INTERNAL. DO NOT USE. */
+  module Internal {
+    /** An empty class that some tests are using to enforce that SourceNode is non-recursive. */
+    abstract class RecursionGuard extends DataFlow::Node { }
+  }
 }
 
 deprecated class DefaultSourceNode extends SourceNode {

javascript/ql/src/semmle/javascript/internal/CachedStages.qll

@@ -133,6 +133,8 @@ module Stages {
       exists(any(DataFlow::Node node).toString())
       or
       exists(any(AccessPath a).getAnInstanceIn(_))
+      or
+      exists(any(DataFlow::PropRef ref).getBase())
     }
   }