Merge pull request github#14502 from geoffw0/xmlquery

Swift: Model RawRepresentable

Author: geoffw0

swift/ql/lib/change-notes/2023-10-13-rawrepresentable.md

@@ -0,0 +1,5 @@
+---
+category: minorAnalysis
+---
+
+* Added taint flow models for `RawRepresentable`.

swift/ql/lib/codeql/swift/frameworks/StandardLibrary/RawRepresentable.qll

@@ -0,0 +1,28 @@
+/**
+ * Provides models the `RawRepresentable` Swift class.
+ */
+
+import swift
+private import codeql.swift.dataflow.DataFlow
+private import codeql.swift.dataflow.ExternalFlow
+private import codeql.swift.dataflow.FlowSteps
+
+/**
+ * A model for `RawRepresentable` class members that permit taint flow.
+ */
+private class RawRepresentableSummaries extends SummaryModelCsv {
+  override predicate row(string row) {
+    row = ";RawRepresentable;true;init(rawValue:);;;Argument[0];ReturnValue;taint"
+  }
+}
+
+/**
+ * A content implying that, if a `RawRepresentable` is tainted, then the
+ * `rawValue` field is tainted as well. This model has been extended to assume
+ * that any object's `rawValue` field also inherits taint.
+ */
+private class RawRepresentableFieldsInheritTaint extends TaintInheritingContent,
+  DataFlow::Content::FieldContent
+{
+  RawRepresentableFieldsInheritTaint() { this.getField().getName() = "rawValue" }
+}

swift/ql/lib/codeql/swift/frameworks/StandardLibrary/StandardLibrary.qll

@@ -17,6 +17,7 @@ private import NsObject
 private import NsString
 private import NsUrl
 private import Numeric
+private import RawRepresentable
 private import PointerTypes
 private import Sequence
 private import Set

swift/ql/lib/codeql/swift/security/XXEExtensions.qll

@@ -172,31 +172,12 @@ private class Libxml2XxeSink extends XxeSink {
   Libxml2XxeSink() {
     exists(Libxml2ParseCall c, Libxml2BadOption opt |
       this.asExpr() = c.getXml() and
-      lib2xmlOptionLocalTaintStep*(DataFlow::exprNode(opt.getAnAccess()),
+      TaintTracking::localTaintStep*(DataFlow::exprNode(opt.getAnAccess()),
         DataFlow::exprNode(c.getOptions()))
     )
   }
 }
 
-/**
- * Holds if taint can flow from `source` to `sink` in one local step,
- * including bitwise operations, accesses to `.rawValue`, and casts to `Int32`.
- */
-private predicate lib2xmlOptionLocalTaintStep(DataFlow::Node source, DataFlow::Node sink) {
-  TaintTracking::localTaintStep(source, sink)
-  or
-  exists(MemberRefExpr rawValue | rawValue.getMember().(VarDecl).getName() = "rawValue" |
-    source.asExpr() = rawValue.getBase() and sink.asExpr() = rawValue
-  )
-  or
-  exists(ApplyExpr int32Init |
-    int32Init.getStaticTarget().(Initializer).getEnclosingDecl().asNominalTypeDecl().getName() =
-      "SignedInteger"
-  |
-    source.asExpr() = int32Init.getAnArgument().getExpr() and sink.asExpr() = int32Init
-  )
-}
-
 /**
  * A sink defined in a CSV model.
  */

swift/ql/test/library-tests/dataflow/taint/libraries/optionset.swift

@@ -0,0 +1,66 @@
+
+// --- stubs ---
+
+// --- tests ---
+
+func sourceInt() -> Int { return 0 }
+func sourceUInt() -> UInt { return 0 }
+func sink(arg: Any) {}
+
+// ---
+
+enum MyRawRepresentable : RawRepresentable {
+  case valueOne
+  case valueTwo
+
+	init?(rawValue: Int) {
+    switch rawValue {
+      case 1: self = .valueOne
+      case 2: self = .valueTwo
+      default: return nil
+    }
+  }
+
+  var rawValue: Int {
+    switch self {
+      case .valueOne: return 1
+      case .valueTwo: return 2
+    }
+  }
+}
+
+func testRawRepresentable() {
+  let rr1 = MyRawRepresentable.valueOne
+  let rr2 = MyRawRepresentable(rawValue: 1)!
+  let rr3 = MyRawRepresentable(rawValue: sourceInt())!
+
+  sink(arg: rr1)
+  sink(arg: rr2)
+  sink(arg: rr3) // $ tainted=35
+
+  sink(arg: rr1.rawValue)
+  sink(arg: rr2.rawValue)
+  sink(arg: rr3.rawValue) // $ tainted=35
+}
+
+// ---
+
+struct MyOptionSet : OptionSet {
+	let rawValue: UInt
+
+	static let red = MyOptionSet(rawValue: 1 << 0)
+	static let green = MyOptionSet(rawValue: 1 << 1)
+	static let blue = MyOptionSet(rawValue: 1 << 2)
+}
+
+func testOptionSet() {
+	sink(arg: MyOptionSet.red)
+	sink(arg: MyOptionSet([.red, .green]))
+	sink(arg: MyOptionSet(rawValue: 0))
+	sink(arg: MyOptionSet(rawValue: sourceUInt())) // $ tainted=60
+
+	sink(arg: MyOptionSet.red.rawValue)
+	sink(arg: MyOptionSet([.red, .green]).rawValue)
+	sink(arg: MyOptionSet(rawValue: 0).rawValue)
+	sink(arg: MyOptionSet(rawValue: sourceUInt()).rawValue) // $ tainted=65
+}

swift/ql/test/query-tests/Security/CWE-611/XXETest.expected

@@ -1,2 +1,2 @@
-failures
 testFailures
+failures