[$csp4 adblockpluschrome] Issue 5241 - Add support for Content Security Policy filters

lib/csp.js

Index: lib/csp.js
diff --git a/lib/csp.js b/lib/csp.js
index 6e7656d1b552a99a74279fefe5fe037a13a89840..693adf0f0a383c32851844f24311900152614a55 100644
--- a/lib/csp.js
+++ b/lib/csp.js
@@ -17,53 +17,66 @@
 
 "use strict";
 
-// The webRequest API doesn't support WebSocket connection blocking in Microsoft
-// Edge and versions of Chrome before 58. Therefore for those we inject CSP
-// headers below as a workaround. See https://crbug.com/129353 and
-// https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/10297376/
-if (!browser.webRequest.ResourceType ||
-    !("WEBSOCKET" in browser.webRequest.ResourceType))
+const {defaultMatcher} = require("matcher");
+const {BlockingFilter, RegExpFilter} = require("filterClasses");
+const {extractHostFromFrame, getDecodedHostname,
+       isThirdParty, stringifyURL} = require("url");
+const {checkWhitelisted} = require("whitelisting");
+const {FilterNotifier} = require("filterNotifier");
+const devtools = require("devtools");
+
+const {typeMap} = RegExpFilter;
+
+browser.webRequest.onHeadersReceived.addListener(details =>
 {
-  const {defaultMatcher} = require("matcher");
-  const {BlockingFilter, RegExpFilter} = require("filterClasses");
-  const {getDecodedHostname} = require("url");
-  const {checkWhitelisted} = require("whitelisting");
+  let url = new URL(details.url);
+  let urlString = stringifyURL(url);
+
+  let parentFrame = details.parentFrameId != -1 &&
+                      ext.getFrame(details.tabId, details.parentFrameId);
+  let hostname = extractHostFromFrame(parentFrame);
+  let thirdParty = false;
+  if (hostname)
+    thirdParty = isThirdParty(url, hostname);
+  else
+    hostname = getDecodedHostname(url);

[Sebastian Noack, 2018/03/16 23:52:38]

Is this micro-optimization worth it? Otherwise, this code could be simplified:

  let hostname = extractHostFromFrame(parentFrame) || getDecodedHostname(url);
  let thirdParty = isThirdParty(url, hostname);

[kzar, 2018/03/19 14:41:30]

Done.

 
-  browser.webRequest.onHeadersReceived.addListener(details =>
+  let cspMatch = defaultMatcher.matchesAny(urlString, typeMap.CSP, hostname,
+                                           thirdParty, null, false);
+  if (cspMatch)
   {
-    let hostname = getDecodedHostname(new URL(details.url));
-    let match = defaultMatcher.matchesAny("", RegExpFilter.typeMap.WEBSOCKET,
-                                          hostname, false, null, true);
-    if (match instanceof BlockingFilter &&
-        !checkWhitelisted(new ext.Page({id: details.tabId}),
-                          ext.getFrame(details.tabId, details.frameId)))
+    let page = new ext.Page({id: details.tabId, url: details.url});
+    let frame = ext.getFrame(details.tabId, details.frameId);
+
+    // To avoid an extra matchesAny for the common case we assumed no
+    // $genericblock filters applied when searching for a matching $csp filter.
+    // We must now pay the price by first checking for a $genericblock filter
+    // and if necessary that our $csp filter is specific.
+    let specificOnly = checkWhitelisted(page, frame, typeMap.GENERICBLOCK);
+    if (specificOnly)
     {
-      details.responseHeaders.push({
-        name: "Content-Security-Policy",
-        // We're blocking WebSockets here by adding a connect-src restriction
-        // since the Chrome extension API does not allow us to intercept them.
-        // https://bugs.chromium.org/p/chromium/issues/detail?id=129353
-        //
-        // We also need the frame-src and object-src restrictions since CSPs
-        // are not inherited from the parent for documents with data: and blob:
-        // URLs, see https://crbug.com/513860.
-        //
-        // We must use the deprecated child-src directive instead of worker-src
-        // since that's not supported yet (as of Chrome 56.)
-        //
-        // "http:" also includes "https:" implictly.
-        // https://www.chromestatus.com/feature/6653486812889088
-        value: "connect-src http:; child-src http:; " +
-               "frame-src http:; object-src http:"
-      });
-      return {responseHeaders: details.responseHeaders};
+      cspMatch = defaultMatcher.matchesAny(urlString, typeMap.CSP, hostname,
+                                           thirdParty, null, specificOnly);
+      if (!cspMatch)
+        return;
     }
-  }, {
-    urls: ["http://*/*", "https://*/*"],
-    // We must also intercept script requests since otherwise Web Workers can
-    // be abused to execute scripts for which our Content Security Policy
-    // won't be injected.
-    // https://github.com/gorhill/uBO-Extra/issues/19
-    types: ["main_frame", "sub_frame", "script"]
-  }, ["blocking", "responseHeaders"]);
-}
+
+    devtools.logRequest(page, urlString, "CSP", hostname, thirdParty, null,
+                        specificOnly, cspMatch);
+
+    if (checkWhitelisted(page, frame))

[Sebastian Noack, 2018/03/16 23:52:39]

Why not doing this check earlier?

[kzar, 2018/03/19 14:41:30]

Done.

+      return;
+
+    FilterNotifier.emit("filter.hitCount", cspMatch, 0, 0, page);
+
+    details.responseHeaders.push({

[Sebastian Noack, 2018/03/16 23:52:38]

It seems this code path is reached if cspMatch is a whitelisting filter.

[kzar, 2018/03/19 14:41:30]

Done.

+      name: "Content-Security-Policy",
+      value: cspMatch.csp
+    });
+
+    return {responseHeaders: details.responseHeaders};
+  }
+}, {
+  urls: ["http://*/*", "https://*/*"],
+  types: ["main_frame", "sub_frame"]
+}, ["blocking", "responseHeaders"]);