From 91e702cebbe52137f59a94f55e46d31f95eb98b9 Mon Sep 17 00:00:00 2001
From: Raymond Hill <rhill@raymondhill.net>
Date: Sun, 1 Dec 2019 12:05:49 -0500
Subject: [PATCH] Enable CNAME uncloaking by default

Advanced setting `cnameAliasList` has been removed.

New advanced settings:

cnameUncloak:
  Boolean
Default value:
  true
Description:
  Whether to CNAME-uncloak hostnames.

cnameIgnoreExceptions:
  Boolean
Default value:
  true
Description:
  Whether to bypass the uncloaking of network requests
  which were excepted by filters/rules. This is
  necessary so as to avoid undue breakage by having
  exception filters being rendered useless as a result
  of CNAME-uncloaking.
  For example, `google-analytics.com` uncloaks to
  `www-google-analytics.l.google.com` and both hostnames
  appear in Peter Lowe's list, which means exception
  filters for `google-analytics.com` (to fix site
  breakage) would be rendered useless as the uncloaking
  would cause the network request to be ultimately
  blocked.
---
 platform/firefox/vapi-webrequest.js | 29 +++++++++++++++++++----------
 src/js/background.js                |  5 +++--
 src/js/storage.js                   |  3 ++-
 src/js/traffic.js                   |  3 ++-
 4 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/platform/firefox/vapi-webrequest.js b/platform/firefox/vapi-webrequest.js
index 93055a2ab..876b8a4ca 100644
--- a/platform/firefox/vapi-webrequest.js
+++ b/platform/firefox/vapi-webrequest.js
@@ -61,19 +61,21 @@
             super();
             this.pendingRequests = [];
             this.cnames = new Map([ [ '', '' ] ]);
-            this.cnameAliasList = null;
             this.cnameIgnoreList = null;
             this.cnameIgnore1stParty = true;
+            this.cnameIgnoreExceptions = true;
             this.cnameIgnoreRootDocument = true;
             this.cnameMaxTTL = 60;
             this.cnameReplayFullURL = false;
             this.cnameTimer = undefined;
+            this.cnameUncloak = true;
         }
         setOptions(options) {
             super.setOptions(options);
-            this.cnameAliasList = this.regexFromStrList(options.cnameAliasList);
+            this.cnameUncloak = options.cnameUncloak !== false;
             this.cnameIgnoreList = this.regexFromStrList(options.cnameIgnoreList);
             this.cnameIgnore1stParty = options.cnameIgnore1stParty !== false;
+            this.cnameIgnoreExceptions = options.cnameIgnoreExceptions !== false;
             this.cnameIgnoreRootDocument = options.cnameIgnoreRootDocument !== false;
             this.cnameMaxTTL = options.cnameMaxTTL || 120;
             this.cnameReplayFullURL = options.cnameReplayFullURL === true;
@@ -199,22 +201,29 @@
             );
         }
         onBeforeSuspendableRequest(details) {
-            let r = super.onBeforeSuspendableRequest(details);
-            if ( r !== undefined ) { return r; }
-            if ( this.cnameAliasList === null ) { return; }
-            if ( details.type === 'main_frame' && this.cnameIgnoreRootDocument ) {
+            const r = super.onBeforeSuspendableRequest(details);
+            if ( r !== undefined ) {
+                if (
+                    r.cancel === true ||
+                    r.redirectUrl !== undefined ||
+                    this.cnameIgnoreExceptions
+                ) {
+                    return r;
+                }
+            }
+            if (
+                details.type === 'main_frame' &&
+                this.cnameIgnoreRootDocument
+            ) {
                 return;
             }
+            if ( this.cnameUncloak === false ) { return; }
             const hn = vAPI.hostnameFromNetworkURL(details.url);
             let cname = this.cnames.get(hn);
             if ( cname === '' ) { return; }
             if ( cname !== undefined ) {
                 return this.processCanonicalName(hn, cname, details);
             }
-            if ( this.cnameAliasList.test(hn) === false ) {
-                this.cnames.set(hn, '');
-                return;
-            }
             return browser.dns.resolve(hn, [ 'canonical_name' ]).then(
                 rec => {
                     const cname = this.recordCanonicalName(hn, rec);
diff --git a/src/js/background.js b/src/js/background.js
index 0860abf79..86ea12ee1 100644
--- a/src/js/background.js
+++ b/src/js/background.js
@@ -46,12 +46,13 @@ const µBlock = (( ) => { // jshint ignore:line
         cacheStorageAPI: 'unset',
         cacheStorageCompression: true,
         cacheControlForFirefox1376932: 'no-cache, no-store, must-revalidate',
-        cnameAliasList: 'unset',
         cnameIgnoreList: 'unset',
         cnameIgnore1stParty: true,
+        cnameIgnoreExceptions: true,
         cnameIgnoreRootDocument: true,
-        cnameMaxTTL: 120,
+        cnameMaxTTL: 60,
         cnameReplayFullURL: false,
+        cnameUncloak: true,
         consoleLogLevel: 'unset',
         debugScriptlets: false,
         debugScriptletInjector: false,
diff --git a/src/js/storage.js b/src/js/storage.js
index 9eeec05b3..7a214dbea 100644
--- a/src/js/storage.js
+++ b/src/js/storage.js
@@ -136,12 +136,13 @@
 self.addEventListener('hiddenSettingsChanged', ( ) => {
     self.log.verbosity = µBlock.hiddenSettings.consoleLogLevel;
     vAPI.net.setOptions({
-        cnameAliasList: µBlock.hiddenSettings.cnameAliasList,
         cnameIgnoreList: µBlock.hiddenSettings.cnameIgnoreList,
         cnameIgnore1stParty: µBlock.hiddenSettings.cnameIgnore1stParty,
+        cnameIgnoreExceptions: µBlock.hiddenSettings.cnameIgnoreExceptions,
         cnameIgnoreRootDocument: µBlock.hiddenSettings.cnameIgnoreRootDocument,
         cnameMaxTTL: µBlock.hiddenSettings.cnameMaxTTL,
         cnameReplayFullURL: µBlock.hiddenSettings.cnameReplayFullURL,
+        cnameUncloak: µBlock.hiddenSettings.cnameUncloak,
     });
 });
 
diff --git a/src/js/traffic.js b/src/js/traffic.js
index 30ba0fd18..8410c9cf2 100644
--- a/src/js/traffic.js
+++ b/src/js/traffic.js
@@ -103,7 +103,8 @@ const onBeforeRequest = function(details) {
         ) {
             pageStore.setFrame(details.frameId, details.url);
         }
-        return;
+        if ( result !== 2 ) { return; }
+        return { cancel: false };
     }
 
     // Blocked