add parameter values from Next as a RemoteFlowSource

javascript/ql/src/javascript.qll

@@ -96,6 +96,7 @@ import semmle.javascript.frameworks.Logging
 import semmle.javascript.frameworks.HttpFrameworks
 import semmle.javascript.frameworks.HttpProxy
 import semmle.javascript.frameworks.Markdown
+import semmle.javascript.frameworks.Next
 import semmle.javascript.frameworks.NoSQL
 import semmle.javascript.frameworks.PkgCloud
 import semmle.javascript.frameworks.PropertyProjection

javascript/ql/src/semmle/javascript/frameworks/Next.qll

@@ -0,0 +1,56 @@
+/**
+ * Provides classes and predicates for reasoning about [Next.js](https://www.npmjs.com/package/next).
+ */
+
+import javascript
+
+/**
+ * Provides classes and predicates modelling [Next.js](https://www.npmjs.com/package/next).
+ */
+private module NextJS {
+  /**
+   * Gets a `package.json` that depends on the `Next.js` library.
+   */
+  PackageJSON getANextPackage() { result.getDependencies().getADependency("next", _) }
+
+  /**
+   * Gets a "pages" folder in a `Next.js` application.
+   * JavaScript files inside these folders are mapped to routes.
+   */
+  Folder getAPagesFolder() {
+    result = getANextPackage().getFile().getParentContainer().getFolder("pages")
+    or
+    result = getAPagesFolder().getAFolder()
+  }
+
+  /**
+   * Gets a module inside a "pages" folder where `fallback` from `getStaticPaths` is not set to false.
+   * In such a module the `getStaticProps` method can be called with user-defined parameters.
+   * If `fallback` is set to false, then only values defined by `getStaticPaths` are allowed.
+   */
+  Module getAModuleWithFallbackPaths() {
+    result.getFile().getParentContainer() = getAPagesFolder() and
+    exists(DataFlow::FunctionNode staticPaths, Expr fallback |
+      staticPaths = result.getAnExportedValue("getStaticPaths").getAFunctionValue() and
+      fallback =
+        staticPaths.getAReturn().getALocalSource().getAPropertyWrite("fallback").getRhs().asExpr() and
+      not fallback.(BooleanLiteral).getValue() = "false"
+    )
+  }
+
+  /**
+   * User defined path parameter in `Next.js`.
+   */
+  class NextParams extends RemoteFlowSource {
+    NextParams() {
+      this =
+        getAModuleWithFallbackPaths()
+            .getAnExportedValue("getStaticProps")
+            .getAFunctionValue()
+            .getParameter(0)
+            .getAPropertyRead("params")
+    }
+
+    override string getSourceType() { result = "Next request parameter" }
+  }
+}

javascript/ql/test/library-tests/frameworks/Next/package.json

@@ -0,0 +1,14 @@
+{
+  "name": "my-app",
+  "version": "0.1.0",
+  "scripts": {
+    "dev": "next dev",
+    "build": "next build",
+    "start": "next start"
+  },
+  "dependencies": {
+    "next": "^10.0.0",
+    "react": "17.0.1",
+    "react-dom": "17.0.1"
+  }
+}

javascript/ql/test/library-tests/frameworks/Next/pages/[my-fallback-id].jsx

@@ -0,0 +1,21 @@
+export async function getStaticPaths() {
+    return {
+        paths: [],
+        fallback: true
+    }
+}
+
+
+export async function getStaticProps({ params }) {
+    return {
+        props: {
+            id: params.id,
+            taint: source()
+        }
+    }
+}
+
+export default function Post({ taint }) {
+    sink(taint);
+    return <span />;
+}

javascript/ql/test/library-tests/frameworks/Next/tests.expected

@@ -0,0 +1,3 @@
+remoteFlow
+| pages/[my-fallback-id].jsx:9:40:9:45 | params |
+dataFlow

javascript/ql/test/library-tests/frameworks/Next/tests.ql

@@ -0,0 +1,19 @@
+import javascript
+
+query RemoteFlowSource remoteFlow() { any() }
+
+class Config extends DataFlow::Configuration {
+  Config() { this = "Config" }
+
+  override predicate isSource(DataFlow::Node source) {
+    source.(DataFlow::CallNode).getCalleeName() = "source"
+  }
+
+  override predicate isSink(DataFlow::Node sink) {
+    exists(DataFlow::CallNode call | call.getCalleeName() = "sink" | call.getAnArgument() = sink)
+  }
+}
+
+query predicate dataFlow(DataFlow::Node pred, DataFlow::Node succ) {
+  any(Config c).hasFlow(pred, succ)
+}