Revert "Remove now obsolete webrtc-related setting"

This reverts commit af41aadab7.

platform/common/vapi-background.js

@@ -122,6 +122,83 @@ vAPI.browserSettings = (( ) => {
     if ( bp instanceof Object === false ) { return; }
 
     return {
+        // Whether the WebRTC-related privacy API is crashy is an open question
+        // only for Chromium proper (because it can be compiled without the
+        // WebRTC feature): hence avoid overhead of the evaluation (which uses
+        // an iframe) for platforms where it's a non-issue.
+        // https://github.com/uBlockOrigin/uBlock-issues/issues/9
+        //   Some Chromium builds are made to look like a Chrome build.
+        webRTCSupported: vAPI.webextFlavor.soup.has('chromium') === false || undefined,
+
+        // Calling with `true` means IP address leak is not prevented.
+        // https://github.com/gorhill/uBlock/issues/533
+        //   We must first check wether this Chromium-based browser was compiled
+        //   with WebRTC support. To do this, we use an iframe, this way the
+        //   empty RTCPeerConnection object we create to test for support will
+        //   be properly garbage collected. This prevents issues such as
+        //   a computer unable to enter into sleep mode, as reported in the
+        //   Chrome store:
+        // https://github.com/gorhill/uBlock/issues/533#issuecomment-167931681
+        setWebrtcIPAddress: function(setting) {
+            // We don't know yet whether this browser supports WebRTC: find out.
+            if ( this.webRTCSupported === undefined ) {
+                // If asked to leave WebRTC setting alone at this point in the
+                // code, this means we never grabbed the setting in the first
+                // place.
+                if ( setting ) { return; }
+                this.webRTCSupported = { setting: setting };
+                let iframe = document.createElement('iframe');
+                const messageHandler = ev => {
+                    if ( ev.origin !== self.location.origin ) { return; }
+                    window.removeEventListener('message', messageHandler);
+                    const setting = this.webRTCSupported.setting;
+                    this.webRTCSupported = ev.data === 'webRTCSupported';
+                    this.setWebrtcIPAddress(setting);
+                    iframe.parentNode.removeChild(iframe);
+                    iframe = null;
+                };
+                window.addEventListener('message', messageHandler);
+                iframe.src = 'is-webrtc-supported.html';
+                document.body.appendChild(iframe);
+                return;
+            }
+
+            // We are waiting for a response from our iframe. This makes the code
+            // safe to re-entrancy.
+            if ( typeof this.webRTCSupported === 'object' ) {
+                this.webRTCSupported.setting = setting;
+                return;
+            }
+
+            // https://github.com/gorhill/uBlock/issues/533
+            // WebRTC not supported: `webRTCMultipleRoutesEnabled` can NOT be
+            // safely accessed. Accessing the property will cause full browser
+            // crash.
+            if ( this.webRTCSupported !== true ) { return; }
+
+            const bpn = bp.network;
+
+            if ( setting ) {
+                bpn.webRTCIPHandlingPolicy.clear({
+                    scope: 'regular',
+                });
+            } else {
+                // https://github.com/uBlockOrigin/uAssets/issues/333#issuecomment-289426678
+                //   Leverage virtuous side-effect of strictest setting.
+                // https://github.com/gorhill/uBlock/issues/3009
+                //   Firefox currently works differently, use
+                //   `default_public_interface_only` for now.
+                // https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/privacy/network#Browser_compatibility
+                //   Firefox 70+ supports `disable_non_proxied_udp`
+                const value =
+                    vAPI.webextFlavor.soup.has('firefox') === false ||
+                    vAPI.webextFlavor.major < 70
+                        ? 'default_public_interface_only'
+                        : 'disable_non_proxied_udp';
+                bpn.webRTCIPHandlingPolicy.set({ value, scope: 'regular' });
+            }
+        },
+
         set: function(details) {
             for ( const setting in details ) {
                 if ( details.hasOwnProperty(setting) === false ) { continue; }
@@ -156,6 +233,10 @@ vAPI.browserSettings = (( ) => {
                     }
                     break;
 
+                case 'webrtcIPAddress':
+                    this.setWebrtcIPAddress(!!details[setting]);
+                    break;
+
                 default:
                     break;
                 }

src/js/background.js

@@ -110,6 +110,7 @@ const userSettingsDefault = {
     requestLogMaxEntries: 1000,
     showIconBadge: true,
     tooltipsDisabled: false,
+    webrtcIPAddressHidden: false,
 };
 
 const µBlock = {  // jshint ignore:line

src/js/settings.js

@@ -176,6 +176,7 @@ const onLocalDataReceived = function(details) {
     if ( details.privacySettingsSupported === false ) {
         uDom('[data-setting-name="prefetchingDisabled"]').attr('disabled', '');
         uDom('[data-setting-name="hyperlinkAuditingDisabled"]').attr('disabled', '');
+        uDom('[data-setting-name="webrtcIPAddressHidden"]').attr('disabled', '');
     }
 };
 

src/js/start.js

@@ -212,6 +212,7 @@ const onUserSettingsReady = function(fetched) {
         vAPI.browserSettings.set({
             'hyperlinkAuditing': !µb.userSettings.hyperlinkAuditingDisabled,
             'prefetching': !µb.userSettings.prefetchingDisabled,
+            'webrtcIPAddress': !µb.userSettings.webrtcIPAddressHidden
         });
     }
 

src/js/ublock.js

@@ -394,6 +394,11 @@ const matchBucket = function(url, hostname, bucket, start) {
             vAPI.browserSettings.set({ 'prefetching': !value });
         }
         break;
+    case 'webrtcIPAddressHidden':
+        if ( this.privacySettingsSupported ) {
+            vAPI.browserSettings.set({ 'webrtcIPAddress': !value });
+        }
+        break;
     default:
         break;
     }

src/settings.html

@@ -26,6 +26,7 @@
     <div class="fieldset-header" data-i18n="3pGroupPrivacy"></div>
     <div class="li"><label><span class="input checkbox"><input type="checkbox" data-setting-name="prefetchingDisabled" data-setting-type="bool"><svg viewBox="0 0 24 24"><path d="M1.73,12.91 8.1,19.28 22.79,4.59"/></svg></span><span><span data-i18n="settingsPrefetchingDisabledPrompt"></span>&nbsp;<a class="fa-icon info" href="https://github.com/gorhill/uBlock/wiki/Dashboard:-Settings#disable-pre-fetching" target="_blank">info-circle</a></span></label></div>
     <div class="li"><label><span class="input checkbox"><input type="checkbox" data-setting-name="hyperlinkAuditingDisabled" data-setting-type="bool"><svg viewBox="0 0 24 24"><path d="M1.73,12.91 8.1,19.28 22.79,4.59"/></svg></span><span><span data-i18n="settingsHyperlinkAuditingDisabledPrompt"></span>&nbsp;<a class="fa-icon info important" href="https://github.com/gorhill/uBlock/wiki/Dashboard:-Settings#disable-hyperlink-auditing" target="_blank">info-circle</a></span></label></div>
+    <div class="li"><label><span class="input checkbox"><input type="checkbox" data-setting-name="webrtcIPAddressHidden" data-setting-type="bool"><svg viewBox="0 0 24 24"><path d="M1.73,12.91 8.1,19.28 22.79,4.59"/></svg></span><span><span data-i18n="settingsWebRTCIPAddressHiddenPrompt"></span>&nbsp;<a class="fa-icon info important" href="https://github.com/gorhill/uBlock/wiki/Prevent-WebRTC-from-leaking-local-IP-address" target="_blank">info-circle</a></span></label></div>
     <div class="li"><label><span class="input checkbox"><input type="checkbox" data-setting-name="noCSPReports" data-setting-type="bool"><svg viewBox="0 0 24 24"><path d="M1.73,12.91 8.1,19.28 22.79,4.59"/></svg></span><span><span data-i18n="settingsNoCSPReportsPrompt"></span>&nbsp;<a class="fa-icon info" href="https://github.com/gorhill/uBlock/wiki/Dashboard:-Settings#block-csp-reports" target="_blank">info-circle</a></span></label></div>
     <div class="li"><label><span class="input checkbox"><input type="checkbox" data-setting-name="cnameUncloakEnabled" data-setting-type="bool"><svg viewBox="0 0 24 24"><path d="M1.73,12.91 8.1,19.28 22.79,4.59"/></svg></span><span><span data-i18n="settingsUncloakCnamePrompt"></span>&nbsp;<a class="fa-icon info" href="https://github.com/gorhill/uBlock/wiki/Dashboard:-Settings#uncloak-canonical-names" target="_blank">info-circle</a></span></label></div>
 </div>