fix: exception of script injection not respecting aliases (#4376)

Co-authored-by: chrmod <chrmod@ghostery.com>
ghostery · Oct 25, 2024 · 3e6c8ea · 3e6c8ea
1 parent e6565c4
commit 3e6c8ea
Show file tree

Hide file tree

Showing 4 changed files with 82 additions and 11 deletions.
diff --git a/packages/adblocker/src/engine/engine.ts b/packages/adblocker/src/engine/engine.ts
@@ -20,7 +20,7 @@ import {
   fullLists,
 } from '../fetch.js';
 import { HTMLSelector } from '../html-filtering.js';
-import CosmeticFilter from '../filters/cosmetic.js';
+import CosmeticFilter, { normalizeSelector } from '../filters/cosmetic.js';
 import NetworkFilter from '../filters/network.js';
 import { block } from '../filters/dsl.js';
 import { FilterType, IListDiff, IPartialRawDiff, parseFilters } from '../lists.js';
@@ -1091,7 +1091,10 @@ export default class FilterEngine extends EventEmitter<EngineEventHandlers> {
       ) {
         injectionsDisabled = true;
       }
-      unhideExceptions.set(unhide.getSelector(), unhide);
+      unhideExceptions.set(
+        normalizeSelector(unhide, this.resources.getScriptletCanonicalName.bind(this.resources)),
+        unhide,
+      );
     }
 
     const injections: CosmeticFilter[] = [];
@@ -1102,7 +1105,9 @@ export default class FilterEngine extends EventEmitter<EngineEventHandlers> {
       // Apply unhide rules + dispatch
       for (const filter of filters) {
         // Make sure `rule` is not un-hidden by a #@# filter
-        const exception = unhideExceptions.get(filter.getSelector());
+        const exception = unhideExceptions.get(
+          normalizeSelector(filter, this.resources.getScriptletCanonicalName.bind(this.resources)),
+        );
 
         if (exception !== undefined) {
           continue;

diff --git a/packages/adblocker/src/filters/cosmetic.ts b/packages/adblocker/src/filters/cosmetic.ts
@@ -175,6 +175,29 @@ function computeFilterId(
   return hash >>> 0;
 }
 
+export function normalizeSelector(
+  filter: CosmeticFilter,
+  getScriptletCanonicalName: (name: string) => string | undefined,
+): string {
+  const selector = filter.getSelector();
+
+  if (filter.isScriptInject() === false) {
+    return selector;
+  }
+
+  const parsed = filter.parseScript();
+  if (parsed === undefined) {
+    return selector;
+  }
+
+  const canonicalName = getScriptletCanonicalName(parsed.name);
+  if (canonicalName === undefined) {
+    return selector;
+  }
+
+  return selector.replace(parsed.name, canonicalName);
+}
+
 /***************************************************************************
  *  Cosmetic filters parsing
  * ************************************************************************ */
@@ -401,6 +424,7 @@ export default class CosmeticFilter implements IFilter {
   public readonly rawLine: string | undefined;
 
   private id: number | undefined;
+  private scriptletDetails: { name: string; args: string[] } | undefined;
 
   constructor({
     mask,
@@ -422,6 +446,7 @@ export default class CosmeticFilter implements IFilter {
 
     this.id = undefined;
     this.rawLine = rawLine;
+    this.scriptletDetails = undefined;
   }
 
   public isCosmeticFilter(): this is CosmeticFilter {
@@ -680,6 +705,10 @@ export default class CosmeticFilter implements IFilter {
   }
 
   public parseScript(): { name: string; args: string[] } | undefined {
+    if (this.scriptletDetails !== undefined) {
+      return this.scriptletDetails;
+    }
+
     const selector = this.getSelector();
     if (selector.length === 0) {
       return undefined;
@@ -772,7 +801,10 @@ export default class CosmeticFilter implements IFilter {
           .replace(REGEXP_UNICODE_BACKSLASH, '\\')
           .replace(REGEXP_ESCAPED_COMMA, ','),
       );
-    return { name: parts[0], args };
+
+    this.scriptletDetails = { name: parts[0], args };
+
+    return this.scriptletDetails;
   }
 
   public getScript(getScriptlet: (_: string) => string | undefined): string | undefined {

diff --git a/packages/adblocker/src/resources.ts b/packages/adblocker/src/resources.ts
@@ -311,12 +311,7 @@ export default class Resources {
   }
 
   public getScriptlet(name: string): string | undefined {
-    // Scriptlets with names ending with `.fn` is always treated as dependencies
-    if (name.endsWith('.fn')) {
-      return undefined;
-    }
-
-    const scriptlet = this.scriptletsByName.get(name.endsWith('.js') ? name : `${name}.js`);
+    const scriptlet = this.getRawScriptlet(name);
 
     if (scriptlet === undefined) {
       return undefined;
@@ -338,6 +333,19 @@ export default class Resources {
     return script;
   }
 
+  public getScriptletCanonicalName(name: string): string | undefined {
+    return this.getRawScriptlet(name)?.name;
+  }
+
+  private getRawScriptlet(name: string): Scriptlet | undefined {
+    // Scriptlets with names ending with `.fn` are always treated as dependencies
+    if (name.endsWith('.fn')) {
+      return undefined;
+    }
+
+    return this.scriptletsByName.get(name.endsWith('.js') ? name : `${name}.js`);
+  }
+
   private getScriptletDependencies(scriptlet: Scriptlet): string[] {
     const dependencies: Map<string, string> = new Map();
     const queue: string[] = [...scriptlet.dependencies];

diff --git a/packages/adblocker/test/engine/engine.test.ts b/packages/adblocker/test/engine/engine.test.ts
@@ -1035,6 +1035,32 @@ foo.com###selector
         matches: [],
       },
 
+      // = unhide +js() exception with aliasing
+      {
+        filters: ['foo.com##+js(scriptlet)', 'foo.com#@#+js(scriptlet0)'],
+        hostname: 'foo.com',
+        hrefs: [],
+        injections: [],
+        matches: [],
+      },
+      {
+        filters: ['foo.com##+js(scriptlet, arg0, arg1)', 'foo.com#@#+js(scriptlet0, arg0, arg1)'],
+        hostname: 'foo.com',
+        hrefs: [],
+        injections: [],
+        matches: [],
+      },
+      {
+        filters: [
+          'foo.com##+js(scriptlet ,  malformed)',
+          'foo.com#@#+js(scriptlet0 ,  malformed)',
+        ],
+        hostname: 'foo.com',
+        hrefs: [],
+        injections: [],
+        matches: [],
+      },
+
       // = unhide +js() disable
       {
         filters: [
@@ -1456,7 +1482,7 @@ foo.com###selector
             scriptlets: [
               {
                 name: 'scriptlet.js',
-                aliases: [],
+                aliases: ['scriptlet0.js'],
                 body: 'function scriptlet() {}',
                 dependencies: [],
                 executionWorld: 'MAIN',