JS: add additional array-specific taint steps

Author: Esben Sparre Andreasen

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

@@ -239,8 +239,28 @@ module TaintTracking {
         succ = call
       )
       or
-      // `array.push(e)`: if `e` is tainted, then so is `array`
-      succ.(DataFlow::SourceNode).getAMethodCall("push") = call
+      // `array.push(e)`, `array.unshift(e)`: if `e` is tainted, then so is `array`.
+      exists (string name |
+        name = "push" or
+        name = "unshift" |
+        pred = call.getAnArgument() and
+        succ.(DataFlow::SourceNode).getAMethodCall(name) = call
+      )
+      or
+      // `e = array.pop()`, `e = array.shift()`, or similar: if `array` is tainted, then so is `e`.
+      exists (string name |
+        name = "pop" or
+        name = "shift" or
+        name = "slice" or
+        name = "splice" |
+        call.(DataFlow::MethodCallNode).calls(pred, name) and
+        succ = call
+      )
+      or
+      // `e = Array.from(x)`: if `x` is tainted, then so is `e`.
+      call = DataFlow::globalVarRef("Array").getAPropertyRead("from").getACall() and
+      pred = call.getAnArgument() and
+      succ = call
     }
 
   }

javascript/ql/test/library-tests/TaintTracking/BasicTaintTracking.expected

@@ -3,3 +3,15 @@
 | tst.js:2:13:2:20 | source() | tst.js:14:10:14:17 | x.sort() |
 | tst.js:2:13:2:20 | source() | tst.js:17:10:17:10 | a |
 | tst.js:2:13:2:20 | source() | tst.js:19:10:19:10 | a |
+| tst.js:2:13:2:20 | source() | tst.js:23:10:23:10 | b |
+| tst.js:2:13:2:20 | source() | tst.js:25:10:25:16 | x.pop() |
+| tst.js:2:13:2:20 | source() | tst.js:26:10:26:18 | x.shift() |
+| tst.js:2:13:2:20 | source() | tst.js:27:10:27:18 | x.slice() |
+| tst.js:2:13:2:20 | source() | tst.js:28:10:28:19 | x.splice() |
+| tst.js:2:13:2:20 | source() | tst.js:30:10:30:22 | Array.from(x) |
+| tst.js:2:13:2:20 | source() | tst.js:33:14:33:16 | elt |
+| tst.js:2:13:2:20 | source() | tst.js:35:14:35:16 | ary |
+| tst.js:2:13:2:20 | source() | tst.js:39:14:39:16 | elt |
+| tst.js:2:13:2:20 | source() | tst.js:41:14:41:16 | ary |
+| tst.js:2:13:2:20 | source() | tst.js:44:10:44:30 | innocen ... ) => x) |
+| tst.js:2:13:2:20 | source() | tst.js:45:10:45:24 | x.map(x2 => x2) |

javascript/ql/test/library-tests/TaintTracking/tst.js

@@ -18,4 +18,30 @@ function test() {
     a.push(x);
     sink(a); // NOT OK
 
+    var b = [];
+    b.unshift(x);
+    sink(b); // NOT OK
+
+    sink(x.pop()); // NOT OK
+    sink(x.shift()); // NOT OK
+    sink(x.slice()); // NOT OK
+    sink(x.splice()); // NOT OK
+
+    sink(Array.from(x)); // NOT OK
+
+    x.map((elt, i, ary) => {
+        sink(elt); // NOT OK
+        sink(i); // OK
+        sink(ary); // NOT OK
+    });
+
+    x.forEach((elt, i, ary) => {
+        sink(elt); // NOT OK
+        sink(i); // OK
+        sink(ary); // NOT OK
+    });
+
+    sink(innocent.map(() => x)); // NOT OK
+    sink(x.map(x2 => x2)); // NOT OK
+
 }