Merge pull request #78 from microsoft/fix-join-order-in-zipslip-query

C#: Fix join order in `cs/zipslip`

Author: LWSimpkins

csharp/ql/lib/semmle/code/csharp/commons/ComparisonTest.qll

@@ -305,6 +305,7 @@ class ComparisonTest extends TComparisonTest {
   }
 
   /** Gets an argument of this comparison test. */
+  pragma[nomagic]
   Expr getAnArgument() {
     result = this.getFirstArgument() or
     result = this.getSecondArgument()

csharp/ql/lib/semmle/code/csharp/exprs/Call.qll

@@ -40,6 +40,7 @@ class Call extends Expr, @call {
   Callable getTarget() { none() }
 
   /** Gets the `i`th argument to this call, if any. */
+  pragma[nomagic]
   Expr getArgument(int i) { result = this.getChild(i) and i >= 0 }
 
   /**

csharp/ql/lib/semmle/code/csharp/security/dataflow/ZipSlipQuery.qll

@@ -315,8 +315,17 @@ class WrapperSanitizerMethodCall extends SanitizerMethodCall {
     )
   }
 
+  pragma[nomagic]
+  private predicate paramFilePathIndex(int index) {
+    index = wrapperMethod.paramFilePath().getIndex()
+  }
+
+
   override Expr getFilePathArgument() {
-    result = this.getArgument(wrapperMethod.paramFilePath().getIndex())
+    exists(int index |
+      this.paramFilePathIndex(index) and
+      result = this.getArgument(index)
+    )
   }
 }