fix(security): requests with an IP addresses Origin header are not allowed to connect to WebSocket

Author: sapphi-red

lib/Server.js

@@ -2014,7 +2014,8 @@ class Server {
           this.checkHeader(
             /** @type {{ [key: string]: string | undefined }} */
             (req.headers),
-            "host"
+            "host",
+            true
           )
         ) {
           return next();
@@ -2598,8 +2599,8 @@ class Server {
 
         if (
           !headers ||
-          !this.checkHeader(headers, "host") ||
-          !this.checkHeader(headers, "origin")
+          !this.checkHeader(headers, "host", true) ||
+          !this.checkHeader(headers, "origin", false)
         ) {
           this.sendMessage([client], "error", "Invalid Host/Origin header");
 
@@ -3055,9 +3056,10 @@ class Server {
    * @private
    * @param {{ [key: string]: string | undefined }} headers
    * @param {string} headerToCheck
+   * @param {boolean} allowIP
    * @returns {boolean}
    */
-  checkHeader(headers, headerToCheck) {
+  checkHeader(headers, headerToCheck, allowIP) {
     // allow user to opt out of this security check, at their own risk
     // by explicitly enabling allowedHosts
     if (this.options.allowedHosts === "all") {
@@ -3084,7 +3086,10 @@ class Server {
       true
     ).hostname;
 
-    // always allow requests with explicit IPv4 or IPv6-address.
+    // allow requests with explicit IPv4 or IPv6-address if allowIP is true.
+    // Note that IP should not be automatically allowed for Origin headers,
+    // otherwise an untrusted remote IP host can send requests.
+    //
     // A note on IPv6 addresses:
     // hostHeader will always contain the brackets denoting
     // an IPv6-address in URLs,
@@ -3094,8 +3099,9 @@ class Server {
     // and its subdomains (hostname.endsWith(".localhost")).
     // allow hostname of listening address  (hostname === this.options.host)
     const isValidHostname =
-      (hostname !== null && ipaddr.IPv4.isValid(hostname)) ||
-      (hostname !== null && ipaddr.IPv6.isValid(hostname)) ||
+      (allowIP &&
+        hostname !== null &&
+        (ipaddr.IPv4.isValid(hostname) || ipaddr.IPv6.isValid(hostname))) ||
       hostname === "localhost" ||
       (hostname !== null && hostname.endsWith(".localhost")) ||
       hostname === this.options.host;

test/e2e/__snapshots__/allowed-hosts.test.js.snap.webpack5

@@ -274,6 +274,32 @@ exports[`allowed hosts should disconnect web client using localhost to web socke
 
 exports[`allowed hosts should disconnect web client using localhost to web socket server with the "auto" value ("ws"): page errors 1`] = `Array []`;
 
+exports[`allowed hosts should disconnect web client with origin header containing an IP address with the "auto" value ("sockjs"): console messages 1`] = `
+[
+  "[webpack-dev-server] Server started: Hot Module Replacement enabled, Live Reloading enabled, Progress disabled, Overlay enabled.",
+  "[HMR] Waiting for update signal from WDS...",
+  "Hey.",
+  "[webpack-dev-server] Invalid Host/Origin header",
+  "[webpack-dev-server] Disconnected!",
+  "[webpack-dev-server] Trying to reconnect...",
+]
+`;
+
+exports[`allowed hosts should disconnect web client with origin header containing an IP address with the "auto" value ("sockjs"): page errors 1`] = `[]`;
+
+exports[`allowed hosts should disconnect web client with origin header containing an IP address with the "auto" value ("ws"): console messages 1`] = `
+[
+  "[webpack-dev-server] Server started: Hot Module Replacement enabled, Live Reloading enabled, Progress disabled, Overlay enabled.",
+  "[HMR] Waiting for update signal from WDS...",
+  "Hey.",
+  "[webpack-dev-server] Invalid Host/Origin header",
+  "[webpack-dev-server] Disconnected!",
+  "[webpack-dev-server] Trying to reconnect...",
+]
+`;
+
+exports[`allowed hosts should disconnect web client with origin header containing an IP address with the "auto" value ("ws"): page errors 1`] = `[]`;
+
 exports[`allowed hosts should disconnect web socket client using custom hostname from web socket server with the "auto" value based on the "host" header ("sockjs"): console messages 1`] = `
 Array [
   "[webpack-dev-server] Server started: Hot Module Replacement enabled, Live Reloading enabled, Progress disabled, Overlay enabled.",

test/e2e/allowed-hosts.test.js

@@ -1147,6 +1147,86 @@ describe("allowed hosts", () => {
       await browser.close();
       await server.stop();
     });
+
+    it(`should disconnect web client with origin header containing an IP address with the "auto" value ("${webSocketServer}")`, async () => {
+      const devServerHost = "127.0.0.1";
+      const devServerPort = port1;
+      const proxyHost = devServerHost;
+      const proxyPort = port2;
+
+      const compiler = webpack(config);
+      const devServerOptions = {
+        client: {
+          webSocketURL: {
+            port: port2,
+          },
+        },
+        webSocketServer,
+        port: devServerPort,
+        host: devServerHost,
+        allowedHosts: "auto",
+      };
+      const server = new Server(devServerOptions, compiler);
+
+      await server.start();
+
+      function startProxy(callback) {
+        const app = express();
+
+        app.use(
+          "/",
+          createProxyMiddleware({
+            // Emulation
+            onProxyReqWs: (proxyReq) => {
+              proxyReq.setHeader("origin", "http://192.168.1.1/");
+            },
+            target: `http://${devServerHost}:${devServerPort}`,
+            ws: true,
+            changeOrigin: true,
+            logLevel: "warn",
+          })
+        );
+
+        return app.listen(proxyPort, proxyHost, callback);
+      }
+
+      const proxy = await new Promise((resolve) => {
+        const proxyCreated = startProxy(() => {
+          resolve(proxyCreated);
+        });
+      });
+
+      const { page, browser } = await runBrowser();
+
+      try {
+        const pageErrors = [];
+        const consoleMessages = [];
+
+        page
+          .on("console", (message) => {
+            consoleMessages.push(message);
+          })
+          .on("pageerror", (error) => {
+            pageErrors.push(error);
+          });
+
+        await page.goto(`http://${proxyHost}:${proxyPort}/`, {
+          waitUntil: "networkidle0",
+        });
+
+        expect(
+          consoleMessages.map((message) => message.text())
+        ).toMatchSnapshot("console messages");
+        expect(pageErrors).toMatchSnapshot("page errors");
+      } catch (error) {
+        throw error;
+      } finally {
+        proxy.close();
+
+        await browser.close();
+        await server.stop();
+      }
+    });
   }
 
   describe("check host headers", () => {

types/lib/Server.d.ts

@@ -3463,6 +3463,7 @@ declare class Server {
    * @private
    * @param {{ [key: string]: string | undefined }} headers
    * @param {string} headerToCheck
+   * @param {boolean} allowIP
    * @returns {boolean}
    */
   private checkHeader;