Bug 1635566 - TRR: lowercase cname after reading it from the packet r=necko-reviewers,dragana

Differential Revision: https://phabricator.services.mozilla.com/D75079

netwerk/dns/TRR.cpp

@@ -919,6 +919,7 @@ nsresult TRR::DohDecode(nsCString& aHost) {
               return rv;
             }
             if (!qname.IsEmpty()) {
+              ToLowerCase(qname);
               mCname = qname;
               LOG(("TRR::DohDecode CNAME host %s => %s\n", host.get(),
                    mCname.get()));

netwerk/test/unit/test_trr_case_sensitivity.js

@@ -0,0 +1,129 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const dns = Cc["@mozilla.org/network/dns-service;1"].getService(
+  Ci.nsIDNSService
+);
+
+trr_test_setup();
+registerCleanupFunction(async () => {
+  trr_clear_prefs();
+});
+
+function makeChan(url) {
+  let chan = NetUtil.newChannel({
+    uri: url,
+    loadUsingSystemPrincipal: true,
+  }).QueryInterface(Ci.nsIHttpChannel);
+  return chan;
+}
+
+let processId;
+
+function channelOpenPromise(chan) {
+  return new Promise(resolve => {
+    function finish(req, buffer) {
+      resolve([req, buffer]);
+    }
+    chan.asyncOpen(new ChannelListener(finish));
+  });
+}
+
+add_task(async function test_trr_casing() {
+  let trrServer = new TRRServer();
+  registerCleanupFunction(async () => trrServer.stop());
+  await trrServer.start();
+  dump(`port = ${trrServer.port}\n`);
+  let chan = makeChan(`https://localhost:${trrServer.port}/test?bla=some`);
+  let [req, resp] = await channelOpenPromise(chan);
+  equal(resp, "<h1> 404 Path not found: /test?bla=some</h1>");
+
+  dns.clearCache(true);
+  Services.prefs.setIntPref("network.trr.mode", 3);
+  Services.prefs.setCharPref(
+    "network.trr.uri",
+    `https://foo.example.com:${trrServer.port}/dns-query`
+  );
+
+  // This CNAME response goes to B.example.com (uppercased)
+  // It should be lowercased by the code
+  await trrServer.registerDoHAnswers("a.example.com", "A", [
+    {
+      name: "a.example.com",
+      ttl: 55,
+      type: "CNAME",
+      flush: false,
+      data: "B.example.com",
+    },
+  ]);
+  // Like in bug 1635566, the response for B.example.com will be lowercased
+  // by the server too -> b.example.com
+  // Requesting this resource would case the browser to reject the resource
+  await trrServer.registerDoHAnswers("B.example.com", "A", [
+    {
+      name: "b.example.com",
+      ttl: 55,
+      type: "CNAME",
+      flush: false,
+      data: "c.example.com",
+    },
+  ]);
+
+  // The browser should request this one
+  await trrServer.registerDoHAnswers("b.example.com", "A", [
+    {
+      name: "b.example.com",
+      ttl: 55,
+      type: "CNAME",
+      flush: false,
+      data: "c.example.com",
+    },
+  ]);
+  // Finally, it gets an IP
+  await trrServer.registerDoHAnswers("c.example.com", "A", [
+    {
+      name: "c.example.com",
+      ttl: 55,
+      type: "A",
+      flush: false,
+      data: "1.2.3.4",
+    },
+  ]);
+  await new TRRDNSListener("a.example.com", "1.2.3.4");
+
+  await trrServer.registerDoHAnswers("a.test.com", "A", [
+    {
+      name: "a.test.com",
+      ttl: 55,
+      type: "CNAME",
+      flush: false,
+      data: "B.test.com",
+    },
+  ]);
+  // We try this again, this time we explicitly make sure this resource
+  // is never used
+  await trrServer.registerDoHAnswers("B.test.com", "A", [
+    {
+      name: "B.test.com",
+      ttl: 55,
+      type: "A",
+      flush: false,
+      data: "9.9.9.9",
+    },
+  ]);
+  await trrServer.registerDoHAnswers("b.test.com", "A", [
+    {
+      name: "b.test.com",
+      ttl: 55,
+      type: "A",
+      flush: false,
+      data: "8.8.8.8",
+    },
+  ]);
+  await new TRRDNSListener("a.test.com", "8.8.8.8");
+
+  await trrServer.stop();
+});

netwerk/test/unit/xpcshell.ini

@@ -426,3 +426,4 @@ skip-if = true || asan || tsan || os == 'win' || os =='android'
 [test_dns_override.js]
 [test_no_cookies_after_last_pb_exit.js]
 [test_trr_httpssvc.js]
+[test_trr_case_sensitivity.js]