recognize more re-exported values as exported

Author: erik-krogh

javascript/ql/lib/semmle/javascript/PackageExports.qll

@@ -75,6 +75,16 @@ private DataFlow::Node getAValueExportedByPackage() {
     result = getAnExportFromModule(mod)
   )
   or
+  // re-export of a value from another module
+  // `module.exports.foo = require("./other").bar;`
+  // other.js:
+  // `module.exports.bar = function () { ... };`
+  exists(DataFlow::PropRead read, Import imp |
+    read = getAValueExportedByPackage() and
+    read.getBase().getALocalSource().getEnclosingExpr() = imp and
+    result = imp.getImportedModule().getAnExportedValue(read.getPropertyName())
+  )
+  or
   // require("./other-module.js"); inside an AMD module.
   exists(Module mod, CallExpr call |
     call = getAValueExportedByPackage().asExpr() and

javascript/ql/test/query-tests/Security/CWE-915/PrototypePollutingAssignment/PrototypePollutingAssignment.expected

@@ -117,6 +117,12 @@ nodes
 | lib.js:128:9:128:20 | obj[path[0]] |
 | lib.js:128:13:128:16 | path |
 | lib.js:128:13:128:19 | path[0] |
+| sublib/other.js:5:28:5:31 | path |
+| sublib/other.js:5:28:5:31 | path |
+| sublib/other.js:6:7:6:18 | obj[path[0]] |
+| sublib/other.js:6:7:6:18 | obj[path[0]] |
+| sublib/other.js:6:11:6:14 | path |
+| sublib/other.js:6:11:6:17 | path[0] |
 | sublib/sub.js:1:37:1:40 | path |
 | sublib/sub.js:1:37:1:40 | path |
 | sublib/sub.js:2:3:2:14 | obj[path[0]] |
@@ -287,6 +293,11 @@ edges
 | lib.js:128:13:128:16 | path | lib.js:128:13:128:19 | path[0] |
 | lib.js:128:13:128:19 | path[0] | lib.js:128:9:128:20 | obj[path[0]] |
 | lib.js:128:13:128:19 | path[0] | lib.js:128:9:128:20 | obj[path[0]] |
+| sublib/other.js:5:28:5:31 | path | sublib/other.js:6:11:6:14 | path |
+| sublib/other.js:5:28:5:31 | path | sublib/other.js:6:11:6:14 | path |
+| sublib/other.js:6:11:6:14 | path | sublib/other.js:6:11:6:17 | path[0] |
+| sublib/other.js:6:11:6:17 | path[0] | sublib/other.js:6:7:6:18 | obj[path[0]] |
+| sublib/other.js:6:11:6:17 | path[0] | sublib/other.js:6:7:6:18 | obj[path[0]] |
 | sublib/sub.js:1:37:1:40 | path | sublib/sub.js:2:7:2:10 | path |
 | sublib/sub.js:1:37:1:40 | path | sublib/sub.js:2:7:2:10 | path |
 | sublib/sub.js:2:7:2:10 | path | sublib/sub.js:2:7:2:13 | path[0] |
@@ -354,6 +365,7 @@ edges
 | lib.js:108:3:108:10 | obj[one] | lib.js:104:13:104:21 | arguments | lib.js:108:3:108:10 | obj[one] | This assignment may alter Object.prototype if a malicious '__proto__' string is injected from $@. | lib.js:104:13:104:21 | arguments | library input |
 | lib.js:119:13:119:24 | obj[path[0]] | lib.js:118:29:118:32 | path | lib.js:119:13:119:24 | obj[path[0]] | This assignment may alter Object.prototype if a malicious '__proto__' string is injected from $@. | lib.js:118:29:118:32 | path | library input |
 | lib.js:128:9:128:20 | obj[path[0]] | lib.js:127:14:127:17 | path | lib.js:128:9:128:20 | obj[path[0]] | This assignment may alter Object.prototype if a malicious '__proto__' string is injected from $@. | lib.js:127:14:127:17 | path | library input |
+| sublib/other.js:6:7:6:18 | obj[path[0]] | sublib/other.js:5:28:5:31 | path | sublib/other.js:6:7:6:18 | obj[path[0]] | This assignment may alter Object.prototype if a malicious '__proto__' string is injected from $@. | sublib/other.js:5:28:5:31 | path | library input |
 | sublib/sub.js:2:3:2:14 | obj[path[0]] | sublib/sub.js:1:37:1:40 | path | sublib/sub.js:2:3:2:14 | obj[path[0]] | This assignment may alter Object.prototype if a malicious '__proto__' string is injected from $@. | sublib/sub.js:1:37:1:40 | path | library input |
 | tst.js:8:5:8:17 | object[taint] | tst.js:5:24:5:37 | req.query.data | tst.js:8:5:8:17 | object[taint] | This assignment may alter Object.prototype if a malicious '__proto__' string is injected from $@. | tst.js:5:24:5:37 | req.query.data | user controlled input |
 | tst.js:9:5:9:17 | object[taint] | tst.js:5:24:5:37 | req.query.data | tst.js:9:5:9:17 | object[taint] | This assignment may alter Object.prototype if a malicious '__proto__' string is injected from $@. | tst.js:5:24:5:37 | req.query.data | user controlled input |

javascript/ql/test/query-tests/Security/CWE-915/PrototypePollutingAssignment/sublib/other.js

@@ -3,9 +3,13 @@
 
   Foobar.prototype = {
     method: function (obj, path, value) {
-      obj[path[0]][path[1]] = value; // NOT OK - but not flagged [INCONSISTENCY]
+      obj[path[0]][path[1]] = value; // NOT OK
     },
   };
 
   module.exports.foobar = Foobar;
+
+  module.other.notExported = function (obj, path, value) {
+    obj[path[0]][path[1]] = value; // OK - not exported
+  }
 })();