Bug 1675054 - Enable brotli encoding for trustworthy URLs, not just for https r=necko-reviewers,dragana

Differential Revision: https://phabricator.services.mozilla.com/D95855

modules/libpref/init/StaticPrefList.yaml

@@ -10781,6 +10781,13 @@
   value: false
   mirror: always
 
+# When this pref is true, we will use the HTTPS acceptable content encoding
+# list for trustworthy domains such as http://localhost
+- name: network.http.encoding.trustworthy_is_https
+  type: RelaxedAtomicBool
+  value: true
+  mirror: always
+
 # Support http3 version1
 - name: network.http.http3.support_version1
   type: RelaxedAtomicBool

netwerk/protocol/http/HttpBaseChannel.cpp

@@ -35,6 +35,7 @@
 #include "mozilla/dom/CanonicalBrowsingContext.h"
 #include "mozilla/dom/Document.h"
 #include "mozilla/dom/nsHTTPSOnlyUtils.h"
+#include "mozilla/dom/nsMixedContentBlocker.h"
 #include "mozilla/dom/Performance.h"
 #include "mozilla/dom/PerformanceStorage.h"
 #include "mozilla/dom/ProcessIsolation.h"
@@ -339,7 +340,10 @@ nsresult HttpBaseChannel::Init(nsIURI* aURI, uint32_t aCaps,
   // Construct connection info object
   nsAutoCString host;
   int32_t port = -1;
-  bool isHTTPS = mURI->SchemeIs("https");
+  bool isHTTPS =
+      StaticPrefs::network_http_encoding_trustworthy_is_https()
+          ? nsMixedContentBlocker::IsPotentiallyTrustworthyLoopbackURL(mURI)
+          : mURI->SchemeIs("https");
 
   nsresult rv = mURI->GetAsciiHost(host);
   if (NS_FAILED(rv)) return rv;
@@ -1254,7 +1258,12 @@ HttpBaseChannel::DoApplyContentConversions(nsIStreamListener* aNextListener,
       break;
     }
 
-    if (gHttpHandler->IsAcceptableEncoding(val, mURI->SchemeIs("https"))) {
+    bool isHTTPS =
+        StaticPrefs::network_http_encoding_trustworthy_is_https()
+            ? nsMixedContentBlocker::IsPotentiallyTrustworthyLoopbackURL(mURI)
+            : mURI->SchemeIs("https");
+
+    if (gHttpHandler->IsAcceptableEncoding(val, isHTTPS)) {
       RefPtr<nsHTTPCompressConv> converter = new nsHTTPCompressConv();
       nsAutoCString from(val);
       ToLowerCase(from);

netwerk/test/unit/test_brotli_http.js

@@ -17,28 +17,55 @@ XPCOMUtils.defineLazyGetter(this, "URL", function() {
 
 var httpServer = null;
 
-add_task(async function test() {
+add_task(async function check_brotli() {
   httpServer = new HttpServer();
   httpServer.registerPathHandler("/content", contentHandler);
   httpServer.start(-1);
+
+  async function test() {
+    let chan = NetUtil.newChannel({ uri: URL, loadUsingSystemPrincipal: true });
+    let [, buff] = await new Promise(resolve => {
+      chan.asyncOpen(
+        new ChannelListener(
+          (req, buff) => {
+            resolve([req, buff]);
+          },
+          null,
+          CL_IGNORE_CL
+        )
+      );
+    });
+    return buff;
+  }
+
+  Services.prefs.setBoolPref(
+    "network.http.encoding.trustworthy_is_https",
+    true
+  );
+  equal(
+    await test(),
+    "hello",
+    "Should decode brotli when trustworthy_is_https=true"
+  );
+  Services.prefs.setBoolPref(
+    "network.http.encoding.trustworthy_is_https",
+    false
+  );
+  equal(
+    await test(),
+    "\x0b\x02\x80hello\x03",
+    "Should not decode brotli when trustworthy_is_https=false"
+  );
   Services.prefs.setCharPref(
     "network.http.accept-encoding",
     "gzip, deflate, br"
   );
-
-  let chan = NetUtil.newChannel({ uri: URL, loadUsingSystemPrincipal: true });
-  let [, buff] = await new Promise(resolve => {
-    chan.asyncOpen(
-      new ChannelListener(
-        (req, buff) => {
-          resolve([req, buff]);
-        },
-        null,
-        CL_IGNORE_CL
-      )
-    );
-  });
-  equal(buff, "hello");
+  equal(
+    await test(),
+    "hello",
+    "Should decode brotli if we set the HTTP accept encoding to include brotli"
+  );
   Services.prefs.clearUserPref("network.http.accept-encoding");
+  Services.prefs.clearUserPref("network.http.encoding.trustworthy_is_https");
   await httpServer.stop();
 });

netwerk/test/unit/test_content_encoding_gzip.js

@@ -181,6 +181,7 @@ function run_test() {
   prefs = Services.prefs;
   cePref = prefs.getCharPref("network.http.accept-encoding");
   prefs.setCharPref("network.http.accept-encoding", "gzip, deflate, br");
+  prefs.setBoolPref("network.http.encoding.trustworthy_is_https", false);
 
   httpserver.registerPathHandler("/test/cegzip1", handler);
   httpserver.registerPathHandler("/test/cegzip2", handler);