Napalys/to spliced support

javascript/ql/lib/change-notes/2024-11-15-toSpliced-support.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+Added taint-steps for `Array.prototype.toSpliced`

javascript/ql/lib/semmle/javascript/Arrays.qll

@@ -81,12 +81,23 @@ module ArrayTaintTracking {
     pred = call.getArgument(any(int i | i >= 2)) and
     succ.(DataFlow::SourceNode).getAMethodCall("splice") = call
     or
+    // `array.toSpliced(x, y, source())`: if `source()` is tainted, then so is the result of `toSpliced`, but not the original array.
+    call.(DataFlow::MethodCallNode).getMethodName() = "toSpliced" and
+    pred = call.getArgument(any(int i | i >= 2)) and
+    succ = call
+    or
     // `array.splice(i, del, ...e)`: if `e` is tainted, then so is `array`.
     pred = call.getASpreadArgument() and
     succ.(DataFlow::SourceNode).getAMethodCall("splice") = call
     or
+    // `array.toSpliced(i, del, ...e)`: if `e` is tainted, then so is the result of `toSpliced`, but not the original array.
+    pred = call.getASpreadArgument() and
+    call.(DataFlow::MethodCallNode).getMethodName() = "toSpliced" and
+    succ = call
+    or
     // `e = array.pop()`, `e = array.shift()`, or similar: if `array` is tainted, then so is `e`.
-    call.(DataFlow::MethodCallNode).calls(pred, ["pop", "shift", "slice", "splice", "at"]) and
+    call.(DataFlow::MethodCallNode)
+        .calls(pred, ["pop", "shift", "slice", "splice", "at", "toSpliced"]) and
     succ = call
     or
     // `e = Array.from(x)`: if `x` is tainted, then so is `e`.
@@ -283,7 +294,7 @@ private module ArrayDataFlow {
   private class ArraySpliceStep extends PreCallGraphStep {
     override predicate storeStep(DataFlow::Node element, DataFlow::SourceNode obj, string prop) {
       exists(DataFlow::MethodCallNode call |
-        call.getMethodName() = "splice" and
+        call.getMethodName() = ["splice", "toSpliced"] and
         prop = arrayElement() and
         element = call.getArgument(any(int i | i >= 2)) and
         call = obj.getAMethodCall()
@@ -297,7 +308,7 @@ private module ArrayDataFlow {
       toProp = arrayElement() and
       // `array.splice(i, del, ...arr)` variant
       exists(DataFlow::MethodCallNode mcn |
-        mcn.getMethodName() = "splice" and
+        mcn.getMethodName() = ["splice", "toSpliced"] and
         pred = mcn.getASpreadArgument() and
         succ = mcn.getReceiver().getALocalSource()
       )
@@ -320,12 +331,12 @@ private module ArrayDataFlow {
   }
 
   /**
-   * A step for modeling that elements from an array `arr` also appear in the result from calling `slice`/`splice`/`filter`.
+   * A step for modeling that elements from an array `arr` also appear in the result from calling `slice`/`splice`/`filter`/`toSpliced`.
    */
   private class ArraySliceStep extends PreCallGraphStep {
     override predicate loadStoreStep(DataFlow::Node pred, DataFlow::SourceNode succ, string prop) {
       exists(DataFlow::MethodCallNode call |
-        call.getMethodName() = ["slice", "splice", "filter"] and
+        call.getMethodName() = ["slice", "splice", "filter", "toSpliced"] and
         prop = arrayElement() and
         pred = call.getReceiver() and
         succ = call

javascript/ql/lib/semmle/javascript/Regexp.qll

@@ -972,7 +972,7 @@ private predicate isUsedAsNumber(DataFlow::LocalSourceNode value) {
   or
   exists(DataFlow::CallNode call |
     call.getCalleeName() =
-      ["substring", "substr", "slice", "splice", "charAt", "charCodeAt", "codePointAt"] and
+      ["substring", "substr", "slice", "splice", "charAt", "charCodeAt", "codePointAt", "toSpliced"] and
     value.flowsTo(call.getAnArgument())
   )
 }

javascript/ql/test/library-tests/Arrays/DataFlow.expected

@@ -13,6 +13,7 @@
 | arrays.js:2:16:2:23 | "source" | arrays.js:86:8:86:35 | arrayFi ... llback) |
 | arrays.js:2:16:2:23 | "source" | arrays.js:90:10:90:10 | x |
 | arrays.js:2:16:2:23 | "source" | arrays.js:93:8:93:17 | arr.at(-1) |
+| arrays.js:2:16:2:23 | "source" | arrays.js:109:8:109:24 | arr8_spread.pop() |
 | arrays.js:18:22:18:29 | "source" | arrays.js:18:50:18:50 | e |
 | arrays.js:22:15:22:22 | "source" | arrays.js:23:8:23:17 | arr2.pop() |
 | arrays.js:25:15:25:22 | "source" | arrays.js:26:8:26:17 | arr3.pop() |
@@ -22,3 +23,5 @@
 | arrays.js:29:21:29:28 | "source" | arrays.js:50:8:50:17 | arr6.pop() |
 | arrays.js:33:37:33:44 | "source" | arrays.js:35:8:35:25 | arr4_variant.pop() |
 | arrays.js:53:4:53:11 | "source" | arrays.js:54:10:54:18 | ary.pop() |
+| arrays.js:99:31:99:38 | "source" | arrays.js:100:8:100:17 | arr8.pop() |
+| arrays.js:103:55:103:62 | "source" | arrays.js:105:8:105:25 | arr8_variant.pop() |

javascript/ql/test/library-tests/Arrays/TaintFlow.expected

@@ -14,6 +14,7 @@
 | arrays.js:2:16:2:23 | "source" | arrays.js:86:8:86:35 | arrayFi ... llback) |
 | arrays.js:2:16:2:23 | "source" | arrays.js:90:10:90:10 | x |
 | arrays.js:2:16:2:23 | "source" | arrays.js:93:8:93:17 | arr.at(-1) |
+| arrays.js:2:16:2:23 | "source" | arrays.js:109:8:109:24 | arr8_spread.pop() |
 | arrays.js:18:22:18:29 | "source" | arrays.js:18:50:18:50 | e |
 | arrays.js:22:15:22:22 | "source" | arrays.js:23:8:23:17 | arr2.pop() |
 | arrays.js:25:15:25:22 | "source" | arrays.js:26:8:26:17 | arr3.pop() |
@@ -26,3 +27,5 @@
 | arrays.js:53:4:53:11 | "source" | arrays.js:55:10:55:12 | ary |
 | arrays.js:95:9:95:16 | "source" | arrays.js:95:8:95:34 | ["sourc ... ) => x) |
 | arrays.js:96:9:96:16 | "source" | arrays.js:96:8:96:36 | ["sourc ... => !!x) |
+| arrays.js:99:31:99:38 | "source" | arrays.js:100:8:100:17 | arr8.pop() |
+| arrays.js:103:55:103:62 | "source" | arrays.js:105:8:105:25 | arr8_variant.pop() |

javascript/ql/test/library-tests/Arrays/arrays.js

@@ -94,4 +94,17 @@
 
   sink(["source"].filter((x) => x)); // NOT OK
   sink(["source"].filter((x) => !!x)); // NOT OK
+
+  var arr8 = [];
+  arr8 = arr8.toSpliced(0, 0, "source");
+  sink(arr8.pop()); // NOT OK
+
+  var arr8_variant = [];
+  arr8_variant = arr8_variant.toSpliced(0, 0, "safe", "source");
+  arr8_variant.pop();
+  sink(arr8_variant.pop()); // NOT OK
+
+  var arr8_spread = [];
+  arr8_spread = arr8_spread.toSpliced(0, 0, ...arr);
+  sink(arr8_spread.pop()); // NOT OK
 });