Add new static network filter option: urltransform

The `urltransform` option allows to redirect a non-blocked network
request to another URL. There are restrictions on its usage:

- require a trusted source -- thus uBO-maintained lists or user
  filters
- the `urltransform` value must start with a `/`

If at least one of these conditions is not fulfilled, the filter
will be invalid and rejected.

The requirement to start with `/` is to enforce that only the path
part of a URL can be modified, thus ensuring the network request
is redirected to the same scheme and authority (as defined at
https://en.wikipedia.org/wiki/Uniform_Resource_Identifier#Syntax).

Usage example (redirect requests for CSS resources to a non-existing
resource, for demonstration purpose):

    ||iana.org^$css,urltransform=/notfound.css

Name of this option is inspired from DNR API:
https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/declarativeNetRequest/URLTransform

This commit required to bring the concept of "trusted source" to
the static network filtering engine.

Author: gorhill

platform/mv3/make-scriptlets.js

@@ -88,7 +88,7 @@ export function compile(details) {
     const scriptletToken = details.args[0];
     const resourceEntry = resourceDetails.get(scriptletToken);
     if ( resourceEntry === undefined ) { return; }
-    if ( resourceEntry.requiresTrust && details.isTrusted !== true ) {
+    if ( resourceEntry.requiresTrust && details.trustedSource !== true ) {
         console.log(`Rejecting ${scriptletToken}: source is not trusted`);
         return;
     }

src/js/1p-filters.js

@@ -48,6 +48,7 @@ const cmEditor = new CodeMirror(qs$('#userFilters'), {
     styleActiveLine: {
         nonEmpty: true,
     },
+    trustedSource: true,
 });
 
 uBlockDashboard.patchCodeMirrorEditor(cmEditor);

src/js/asset-viewer.js

@@ -82,6 +82,7 @@ import './codemirror/ubo-static-filtering.js';
         what : 'getAssetContent',
         url: assetKey,
     });
+    cmEditor.setOption('trustedSource', details.trustedSource === true);
     cmEditor.setValue(details && details.content || '');
 
     if ( subscribeElem !== null ) {

src/js/benchmarks.js

@@ -181,7 +181,8 @@ const loadBenchmarkDataset = (( ) => {
         if ( r === 1 ) { blockCount += 1; }
         else if ( r === 2 ) { allowCount += 1; }
         if ( r !== 1 ) {
-            if ( staticNetFilteringEngine.hasQuery(fctxt) ) {
+            staticNetFilteringEngine.transformRequest(fctxt);
+            if ( fctxt.redirectURL !== undefined && staticNetFilteringEngine.hasQuery(fctxt) ) {
                 staticNetFilteringEngine.filterQuery(fctxt, 'removeparam');
             }
             if ( fctxt.type === 'main_frame' || fctxt.type === 'sub_frame' ) {

src/js/codemirror/ubo-static-filtering.js

@@ -37,12 +37,21 @@ const preparseDirectiveHints = [];
 const originHints = [];
 let hintHelperRegistered = false;
 
+/******************************************************************************/
+
+let trustedSource = false;
+
+CodeMirror.defineOption('trustedSource', false, (cm, state) => {
+    trustedSource = state;
+    self.dispatchEvent(new Event('trustedSource'));
+});
 
 /******************************************************************************/
 
 CodeMirror.defineMode('ubo-static-filtering', function() {
     const astParser = new sfp.AstFilterParser({
         interactive: true,
+        trustedSource,
         nativeCssHas: vAPI.webextFlavor.env.includes('native_css_has'),
     });
     const astWalker = astParser.getWalker();
@@ -205,7 +214,11 @@ CodeMirror.defineMode('ubo-static-filtering', function() {
         return '+';
     };
 
-    return {
+    self.addEventListener('trustedSource', ( ) => {
+        astParser.options.trustedSource = trustedSource;
+    });
+
+   return {
         lineComment: '!',
         token: function(stream) {
             if ( stream.sol() ) {
@@ -977,6 +990,10 @@ CodeMirror.registerHelper('fold', 'ubo-static-filtering', (( ) => {
         }
     };
 
+    self.addEventListener('trustedSource', ( ) => {
+        astParser.options.trustedSource = trustedSource;
+    });
+
     CodeMirror.defineInitHook(cm => {
         cm.on('changes', onChanges);
         cm.on('beforeChange', onBeforeChanges);

src/js/messaging.js

@@ -108,6 +108,7 @@ const onMessage = function(request, sender, callback) {
             dontCache: true,
             needSourceURL: true,
         }).then(result => {
+            result.trustedSource = µb.isTrustedList(result.assetKey);
             callback(result);
         });
         return;

src/js/pagestore.js

@@ -860,7 +860,7 @@ const PageStore = class {
         if ( (fctxt.itype & fctxt.INLINE_ANY) === 0 ) {
             if ( result === 1 ) {
                 this.redirectBlockedRequest(fctxt);
-            } else if ( snfe.hasQuery(fctxt) ) {
+            } else {
                 this.redirectNonBlockedRequest(fctxt);
             }
         }
@@ -922,25 +922,31 @@ const PageStore = class {
     }
 
     redirectBlockedRequest(fctxt) {
-        const directives = staticNetFilteringEngine.redirectRequest(
-            redirectEngine,
-            fctxt
-        );
+        const directives = staticNetFilteringEngine.redirectRequest(redirectEngine, fctxt);
         if ( directives === undefined ) { return; }
         if ( logger.enabled !== true ) { return; }
         fctxt.pushFilters(directives.map(a => a.logData()));
         if ( fctxt.redirectURL === undefined ) { return; }
         fctxt.pushFilter({
             source: 'redirect',
-            raw: redirectEngine.resourceNameRegister
+            raw: directives[directives.length-1].value
         });
     }
 
     redirectNonBlockedRequest(fctxt) {
-        const directives = staticNetFilteringEngine.filterQuery(fctxt);
-        if ( directives === undefined ) { return; }
+        const transformDirectives = staticNetFilteringEngine.transformRequest(fctxt);
+        const pruneDirectives = fctxt.redirectURL === undefined &&
+            staticNetFilteringEngine.hasQuery(fctxt) &&
+            staticNetFilteringEngine.filterQuery(fctxt) ||
+            undefined;
+        if ( transformDirectives === undefined && pruneDirectives === undefined ) { return; }
         if ( logger.enabled !== true ) { return; }
-        fctxt.pushFilters(directives.map(a => a.logData()));
+        if ( transformDirectives !== undefined ) {
+            fctxt.pushFilters(transformDirectives.map(a => a.logData()));
+        }
+        if ( pruneDirectives !== undefined ) {
+            fctxt.pushFilters(pruneDirectives.map(a => a.logData()));
+        }
         if ( fctxt.redirectURL === undefined ) { return; }
         fctxt.pushFilter({
             source: 'redirect',

src/js/redirect-engine.js

@@ -167,7 +167,6 @@ class RedirectEngine {
         this.resources = new Map();
         this.reset();
         this.modifyTime = Date.now();
-        this.resourceNameRegister = '';
     }
 
     reset() {
@@ -183,7 +182,6 @@ class RedirectEngine {
     ) {
         const entry = this.resources.get(this.aliases.get(token) || token);
         if ( entry === undefined ) { return; }
-        this.resourceNameRegister = token;
         return entry.toURL(fctxt, asDataURI);
     }
 

src/js/reverselookup.js

@@ -131,6 +131,7 @@ const fromNetFilter = async function(rawFilter) {
     const writer = new CompiledListWriter();
     const parser = new sfp.AstFilterParser({
         expertMode: true,
+        trustedSource: true,
         maxTokenLength: staticNetFilteringEngine.MAX_TOKEN_LENGTH,
         nativeCssHas: vAPI.webextFlavor.env.includes('native_css_has'),
     });
@@ -169,6 +170,7 @@ const fromExtendedFilter = async function(details) {
 
     const parser = new sfp.AstFilterParser({
         expertMode: true,
+        trustedSource: true,
         nativeCssHas: vAPI.webextFlavor.env.includes('native_css_has'),
     });
     parser.parse(details.rawFilter);

src/js/scriptlet-filtering.js

@@ -306,7 +306,7 @@ scriptletFilteringEngine.compile = function(parser, writer) {
 
     // Only exception filters are allowed to be global.
     const isException = parser.isException();
-    const normalized = normalizeRawFilter(parser, writer.properties.get('isTrusted'));
+    const normalized = normalizeRawFilter(parser, writer.properties.get('trustedSource'));
 
     // Can fail if there is a mismatch with trust requirement
     if ( normalized === undefined ) { return; }