Revert "Bug 1422862: Implement IsImageExtractionAllowed_impl. r=tjr,gfx-reviewers,nical" for causing bc failures @ browser_etp_permission.js

Alexandru Marc · amarc-mozilla · commit 414cd1ce2e11 · 2025-06-11T17:00:09.000Z
This reverts commit 26aa4db. Revert "Bug 1918690: Extend test to also test Offscreen canvases. r=tjr" This reverts commit 4d63bba. Revert "Bug 1918690: Check canvas permission in RandomizePixels function. r=tjr,gfx-reviewers,nical" This reverts commit bf7503d. Revert "Bug 1422862: Show canvas permission prompt for offscreen canvases. r=tjr,gfx-reviewers,nical" This reverts commit b87087b. Revert "Bug 1422862: Check canvas permission in offscreen canvas. r=tjr,gfx-reviewers,nical" This reverts commit ad6b0a2.
diff --git a/dom/canvas/CanvasRenderingContext2D.cpp b/dom/canvas/CanvasRenderingContext2D.cpp
@@ -2144,9 +2144,8 @@ UniquePtr<uint8_t[]> CanvasRenderingContext2D::GetImageBuffer(
 
   if (ret && ShouldResistFingerprinting(RFPTarget::CanvasRandomization)) {
     nsRFPService::RandomizePixels(
-        GetCookieJarSettings(), PrincipalOrNull(), ret.get(),
-        out_imageSize->width, out_imageSize->height,
-        out_imageSize->width * out_imageSize->height * 4,
+        GetCookieJarSettings(), ret.get(), out_imageSize->width,
+        out_imageSize->height, out_imageSize->width * out_imageSize->height * 4,
         SurfaceFormat::A8R8G8B8_UINT32);
   }
 
@@ -6396,10 +6395,9 @@ nsresult CanvasRenderingContext2D::GetImageDataArray(
       // holder.
 
       const IntSize size = readback->GetSize();
-      nsRFPService::RandomizePixels(GetCookieJarSettings(), PrincipalOrNull(),
-                                    rawData.mData, size.width, size.height,
-                                    size.height * size.width * 4,
-                                    SurfaceFormat::A8R8G8B8_UINT32);
+      nsRFPService::RandomizePixels(
+          GetCookieJarSettings(), rawData.mData, size.width, size.height,
+          size.height * size.width * 4, SurfaceFormat::A8R8G8B8_UINT32);
     }
 
     JS::AutoCheckCannotGC nogc;
diff --git a/dom/canvas/CanvasUtils.cpp b/dom/canvas/CanvasUtils.cpp
diff --git a/dom/canvas/CanvasUtils.h b/dom/canvas/CanvasUtils.h
@@ -59,18 +59,10 @@ bool HasDrawWindowPrivilege(JSContext* aCx, JSObject* aObj);
 // Check if the context has permission to use OffscreenCanvas.
 bool IsOffscreenCanvasEnabled(JSContext* aCx, JSObject* aObj);
 
-// Check if the principal has "canvas" permission.
-uint32_t GetCanvasExtractDataPermission(nsIPrincipal& aPrincipal);
-
 // Check site-specific permission and display prompt if appropriate.
 bool IsImageExtractionAllowed(dom::Document* aDocument, JSContext* aCx,
                               nsIPrincipal& aPrincipal);
 
-bool IsImageExtractionAllowed(dom::OffscreenCanvas* aOffscreenCanvas,
-                              JSContext* aCx, nsIPrincipal& aPrincipal);
-
-uint32_t GetCanvasExtractDataPermission(nsIPrincipal& aPrincipal);
-
 enum class ImageExtraction {
   Unrestricted,
   Placeholder,
diff --git a/dom/canvas/ClientWebGLContext.cpp b/dom/canvas/ClientWebGLContext.cpp
@@ -1345,8 +1345,7 @@ UniquePtr<uint8_t[]> ClientWebGLContext::GetImageBuffer(
 
   if (ShouldResistFingerprinting(RFPTarget::CanvasRandomization)) {
     return gfxUtils::GetImageBufferWithRandomNoise(
-        dataSurface, premultAlpha, GetCookieJarSettings(), PrincipalOrNull(),
-        out_format);
+        dataSurface, premultAlpha, GetCookieJarSettings(), out_format);
   }
 
   return gfxUtils::GetImageBuffer(dataSurface, premultAlpha, out_format);
@@ -1367,7 +1366,7 @@ ClientWebGLContext::GetInputStream(const char* mimeType,
   if (ShouldResistFingerprinting(RFPTarget::CanvasRandomization)) {
     return gfxUtils::GetInputStreamWithRandomNoise(
         dataSurface, premultAlpha, mimeType, encoderOptions,
-        GetCookieJarSettings(), PrincipalOrNull(), out_stream);
+        GetCookieJarSettings(), out_stream);
   }
 
   return gfxUtils::GetInputStream(dataSurface, premultAlpha, mimeType,
diff --git a/dom/canvas/ImageBitmapRenderingContext.cpp b/dom/canvas/ImageBitmapRenderingContext.cpp
@@ -195,8 +195,8 @@ mozilla::UniquePtr<uint8_t[]> ImageBitmapRenderingContext::GetImageBuffer(
 
   if (ret && ShouldResistFingerprinting(RFPTarget::CanvasRandomization)) {
     nsRFPService::RandomizePixels(
-        GetCookieJarSettings(), PrincipalOrNull(), ret.get(),
-        data->GetSize().width, data->GetSize().height,
+        GetCookieJarSettings(), ret.get(), data->GetSize().width,
+        data->GetSize().height,
         data->GetSize().width * data->GetSize().height * 4,
         gfx::SurfaceFormat::A8R8G8B8_UINT32);
   }
diff --git a/dom/canvas/OffscreenCanvas.cpp b/dom/canvas/OffscreenCanvas.cpp
@@ -26,7 +26,6 @@
 #include "ImageBitmap.h"
 #include "ImageBitmapRenderingContext.h"
 #include "nsContentUtils.h"
-#include "nsIPermissionManager.h"
 #include "nsProxyRelease.h"
 #include "WebGLChild.h"
 
@@ -504,11 +503,8 @@ already_AddRefed<Promise> OffscreenCanvas::ConvertToBlob(
 
   RefPtr<EncodeCompleteCallback> callback =
       CreateEncodeCompleteCallback(promise);
-
-  bool usePlaceholder = mCurrentContext && mCurrentContext->PrincipalOrNull() &&
-                        !CanvasUtils::IsImageExtractionAllowed(
-                            this, nsContentUtils::GetCurrentJSContext(),
-                            *mCurrentContext->PrincipalOrNull());
+  bool usePlaceholder =
+      ShouldResistFingerprinting(RFPTarget::CanvasImageExtractionPrompt);
   CanvasRenderingContextHelper::ToBlob(callback, type, encodeOptions,
                                        /* aUsingCustomOptions */ false,
                                        usePlaceholder, aRv);
@@ -549,10 +545,8 @@ already_AddRefed<Promise> OffscreenCanvas::ToBlob(JSContext* aCx,
 
   RefPtr<EncodeCompleteCallback> callback =
       CreateEncodeCompleteCallback(promise);
-  bool usePlaceholder = mCurrentContext && mCurrentContext->PrincipalOrNull() &&
-                        !CanvasUtils::IsImageExtractionAllowed(
-                            this, nsContentUtils::GetCurrentJSContext(),
-                            *mCurrentContext->PrincipalOrNull());
+  bool usePlaceholder =
+      ShouldResistFingerprinting(RFPTarget::CanvasImageExtractionPrompt);
   CanvasRenderingContextHelper::ToBlob(aCx, callback, aType, aParams,
                                        usePlaceholder, aRv);
 
diff --git a/dom/canvas/OffscreenCanvasDisplayHelper.cpp b/dom/canvas/OffscreenCanvasDisplayHelper.cpp
@@ -577,21 +577,9 @@ UniquePtr<uint8_t[]> OffscreenCanvasDisplayHelper::GetImageBuffer(
   }
 
   if (resistFingerprinting) {
-    nsIPrincipal* principal;
-    {
-      MutexAutoLock lock(mMutex);
-      if (mCanvasElement) {
-        principal = mCanvasElement->NodePrincipal();
-      }
-      if (mOffscreenCanvas) {
-        principal = mOffscreenCanvas->GetParentObject()
-                        ? mOffscreenCanvas->GetParentObject()->PrincipalOrNull()
-                        : nullptr;
-      }
-    }
     nsRFPService::RandomizePixels(
-        cookieJarSettings, principal, imageBuffer.get(),
-        dataSurface->GetSize().width, dataSurface->GetSize().height,
+        cookieJarSettings, imageBuffer.get(), dataSurface->GetSize().width,
+        dataSurface->GetSize().height,
         dataSurface->GetSize().width * dataSurface->GetSize().height * 4,
         gfx::SurfaceFormat::A8R8G8B8_UINT32);
   }
diff --git a/dom/webgpu/CanvasContext.cpp b/dom/webgpu/CanvasContext.cpp
@@ -353,10 +353,9 @@ mozilla::UniquePtr<uint8_t[]> CanvasContext::GetImageBuffer(
   *out_imageSize = dataSurface->GetSize();
 
   if (ShouldResistFingerprinting(RFPTarget::CanvasRandomization)) {
-    gfxUtils::GetImageBufferWithRandomNoise(dataSurface,
-                                            /* aIsAlphaPremultiplied */ true,
-                                            GetCookieJarSettings(),
-                                            PrincipalOrNull(), &*out_format);
+    gfxUtils::GetImageBufferWithRandomNoise(
+        dataSurface,
+        /* aIsAlphaPremultiplied */ true, GetCookieJarSettings(), &*out_format);
   }
 
   return gfxUtils::GetImageBuffer(dataSurface, /* aIsAlphaPremultiplied */ true,
@@ -375,9 +374,9 @@ NS_IMETHODIMP CanvasContext::GetInputStream(const char* aMimeType,
   RefPtr<gfx::DataSourceSurface> dataSurface = snapshot->GetDataSurface();
 
   if (ShouldResistFingerprinting(RFPTarget::CanvasRandomization)) {
-    return gfxUtils::GetInputStreamWithRandomNoise(
+    gfxUtils::GetInputStreamWithRandomNoise(
         dataSurface, /* aIsAlphaPremultiplied */ true, aMimeType,
-        aEncoderOptions, GetCookieJarSettings(), PrincipalOrNull(), aStream);
+        aEncoderOptions, GetCookieJarSettings(), aStream);
   }
 
   return gfxUtils::GetInputStream(dataSurface, /* aIsAlphaPremultiplied */ true,
diff --git a/gfx/thebes/gfxUtils.cpp b/gfx/thebes/gfxUtils.cpp
@@ -1613,14 +1613,13 @@ UniquePtr<uint8_t[]> gfxUtils::GetImageBuffer(gfx::DataSourceSurface* aSurface,
 /* static */
 UniquePtr<uint8_t[]> gfxUtils::GetImageBufferWithRandomNoise(
     gfx::DataSourceSurface* aSurface, bool aIsAlphaPremultiplied,
-    nsICookieJarSettings* aCookieJarSettings, nsIPrincipal* aPrincipal,
-    int32_t* outFormat) {
+    nsICookieJarSettings* aCookieJarSettings, int32_t* outFormat) {
   UniquePtr<uint8_t[]> imageBuffer =
       GetImageBuffer(aSurface, aIsAlphaPremultiplied, outFormat);
 
   nsRFPService::RandomizePixels(
-      aCookieJarSettings, aPrincipal, imageBuffer.get(),
-      aSurface->GetSize().width, aSurface->GetSize().height,
+      aCookieJarSettings, imageBuffer.get(), aSurface->GetSize().width,
+      aSurface->GetSize().height,
       aSurface->GetSize().width * aSurface->GetSize().height * 4,
       SurfaceFormat::A8R8G8B8_UINT32);
 
@@ -1652,8 +1651,7 @@ nsresult gfxUtils::GetInputStream(gfx::DataSourceSurface* aSurface,
 nsresult gfxUtils::GetInputStreamWithRandomNoise(
     gfx::DataSourceSurface* aSurface, bool aIsAlphaPremultiplied,
     const char* aMimeType, const nsAString& aEncoderOptions,
-    nsICookieJarSettings* aCookieJarSettings, nsIPrincipal* aPrincipal,
-    nsIInputStream** outStream) {
+    nsICookieJarSettings* aCookieJarSettings, nsIInputStream** outStream) {
   nsCString enccid("@mozilla.org/image/encoder;2?type=");
   enccid += aMimeType;
   nsCOMPtr<imgIEncoder> encoder = do_CreateInstance(enccid.get());
@@ -1669,8 +1667,8 @@ nsresult gfxUtils::GetInputStreamWithRandomNoise(
   }
 
   nsRFPService::RandomizePixels(
-      aCookieJarSettings, aPrincipal, imageBuffer.get(),
-      aSurface->GetSize().width, aSurface->GetSize().height,
+      aCookieJarSettings, imageBuffer.get(), aSurface->GetSize().width,
+      aSurface->GetSize().height,
       aSurface->GetSize().width * aSurface->GetSize().height * 4,
       SurfaceFormat::A8R8G8B8_UINT32);
 
diff --git a/gfx/thebes/gfxUtils.h b/gfx/thebes/gfxUtils.h
@@ -400,8 +400,7 @@ class gfxUtils {
 
   static mozilla::UniquePtr<uint8_t[]> GetImageBufferWithRandomNoise(
       DataSourceSurface* aSurface, bool aIsAlphaPremultiplied,
-      nsICookieJarSettings* aCookieJarSettings, nsIPrincipal* aPrincipal,
-      int32_t* outFormat);
+      nsICookieJarSettings* aCookieJarSettings, int32_t* outFormat);
 
   static nsresult GetInputStream(DataSourceSurface* aSurface,
                                  bool aIsAlphaPremultiplied,
@@ -412,8 +411,7 @@ class gfxUtils {
   static nsresult GetInputStreamWithRandomNoise(
       DataSourceSurface* aSurface, bool aIsAlphaPremultiplied,
       const char* aMimeType, const nsAString& aEncoderOptions,
-      nsICookieJarSettings* aCookieJarSettings, nsIPrincipal* aPrincipal,
-      nsIInputStream** outStream);
+      nsICookieJarSettings* aCookieJarSettings, nsIInputStream** outStream);
 
   static void RemoveShaderCacheFromDiskIfNecessary();
 
diff --git a/toolkit/components/resistfingerprinting/nsRFPService.cpp b/toolkit/components/resistfingerprinting/nsRFPService.cpp
@@ -54,7 +54,6 @@
 #include "mozilla/dom/MediaDeviceInfoBinding.h"
 #include "mozilla/fallible.h"
 #include "mozilla/XorShift128PlusRNG.h"
-#include "mozilla/dom/CanvasUtils.h"
 
 #include "nsAboutProtocolUtils.h"
 #include "nsBaseHashtable.h"
@@ -1722,9 +1721,8 @@ nsresult nsRFPService::GenerateCanvasKeyFromImageData(
 
 // static
 nsresult nsRFPService::RandomizePixels(nsICookieJarSettings* aCookieJarSettings,
-                                       nsIPrincipal* aPrincipal, uint8_t* aData,
-                                       uint32_t aWidth, uint32_t aHeight,
-                                       uint32_t aSize,
+                                       uint8_t* aData, uint32_t aWidth,
+                                       uint32_t aHeight, uint32_t aSize,
                                        gfx::SurfaceFormat aSurfaceFormat) {
   NS_ENSURE_ARG_POINTER(aData);
 
@@ -1736,11 +1734,6 @@ nsresult nsRFPService::RandomizePixels(nsICookieJarSettings* aCookieJarSettings,
     return NS_OK;
   }
 
-  if (aPrincipal && CanvasUtils::GetCanvasExtractDataPermission(*aPrincipal) ==
-                        nsIPermissionManager::ALLOW_ACTION) {
-    return NS_OK;
-  }
-
   // Don't randomize if all pixels are uniform.
   static constexpr size_t bytesPerPixel = 4;
   MOZ_ASSERT(aSize == aWidth * aHeight * bytesPerPixel,
diff --git a/toolkit/components/resistfingerprinting/nsRFPService.h b/toolkit/components/resistfingerprinting/nsRFPService.h
@@ -342,9 +342,8 @@ class nsRFPService final : public nsIObserver, public nsIRFPService {
   // The method to add random noises to the image data based on the random key
   // of the given cookieJarSettings.
   static nsresult RandomizePixels(nsICookieJarSettings* aCookieJarSettings,
-                                  nsIPrincipal* aPrincipal, uint8_t* aData,
-                                  uint32_t aWidth, uint32_t aHeight,
-                                  uint32_t aSize,
+                                  uint8_t* aData, uint32_t aWidth,
+                                  uint32_t aHeight, uint32_t aSize,
                                   mozilla::gfx::SurfaceFormat aSurfaceFormat);
 
   // --------------------------------------------------------------------------
diff --git a/toolkit/components/resistfingerprinting/tests/browser/browser_canvas_randomization_permission.js b/toolkit/components/resistfingerprinting/tests/browser/browser_canvas_randomization_permission.js
@@ -19,10 +19,6 @@ function getImageData(tab, isOffscreen, method) {
       ? new OffscreenCanvas(3, 1)
       : document.createElement("canvas");
     const ctx = canvas.getContext("2d");
-    if (!isOffscreen) {
-      canvas.width = 3;
-      canvas.height = 1;
-    }
 
     ctx.fillStyle = "rgb(255, 0, 0)";
     ctx.fillRect(0, 0, 1, 1);
@@ -34,13 +30,13 @@ function getImageData(tab, isOffscreen, method) {
     if (method === "getImageData") {
       return ctx.getImageData(0, 0, 3, 1).data.join(",");
     } else if (method === "toDataURL") {
-      return canvas.toDataURL("image/png", 1);
+      return canvas.toDataURL();
     } else if (method === "toBlob") {
       return new Promise((resolve, reject) => {
         if (isOffscreen) {
-          canvas.toBlob().then(resolve, reject);
+          canvas.convertToBlob().then(resolve, reject);
         } else {
-          canvas.toBlob(resolve, "image/png", 1);
+          canvas.toBlob(resolve, "image/png");
         }
       }).then(blob => {
         const reader = new FileReader();
@@ -50,18 +46,8 @@ function getImageData(tab, isOffscreen, method) {
         reader.onerror = reject;
         return promise;
       });
-    } else if (method === "convertToBlob") {
-      return canvas.convertToBlob().then(blob => {
-        const reader = new FileReader();
-        reader.readAsDataURL(blob);
-        const { promise, resolve, reject } = Promise.withResolvers();
-        reader.onload = () => resolve(reader.result);
-        reader.onerror = reject;
-        return promise;
-      });
     }
-
-    throw new Error("Unknown method");
+    return null;
   };
 
   const extractCanvasExpr = `(${extractCanvas.toString()})(${isOffscreen}, "${method}");`;
@@ -82,7 +68,6 @@ const TEST_CASES = [
   // OffscreenCanvas
   [true, "getImageData", null],
   [true, "toBlob", null],
-  [true, "convertToBlob", null],
 ];
 
 add_setup(async function setup() {
@@ -103,15 +88,8 @@ add_setup(async function setup() {
   for (let i = 0; i < TEST_CASES.length; i++) {
     const test_case = TEST_CASES[i];
     const [isOffscreen, method] = test_case;
-    const readback = await getImageData(tab, isOffscreen, method);
-    if (readback == null || !readback.length) {
-      throw new Error(
-        `Failed to get the initial readback for ${
-          isOffscreen ? "Offscreen Canvas" : "HTML Canvas"
-        } ${method} got ${readback}`
-      );
-    }
-    test_case[2] = readback;
+    const imageData = await getImageData(tab, isOffscreen, method);
+    test_case[2] = imageData;
   }
 
   BrowserTestUtils.removeTab(tab);
@@ -149,13 +127,19 @@ async function runTest(permissionGranted, isRFP) {
   for (let i = 0; i < TEST_CASES.length; i++) {
     const test_case = TEST_CASES[i];
     const [isOffscreen, method, trueValue] = test_case;
-    const readback = await getImageData(tab, isOffscreen, method);
-    const message = `PermissionGranted: ${permissionGranted}; Method: ${method}; Offscreen: ${isOffscreen}; Image should be ${
-      permissionGranted ? "the same" : "different"
-    }`;
+    const imageData = await getImageData(tab, isOffscreen, method);
+    const message = `Image data was ${
+      permissionGranted ? "not " : ""
+    }randomized for ${method} on ${
+      isOffscreen ? "OffscreenCanvas" : "HTMLCanvasElement"
+    }.`;
+    if (isOffscreen) {
+      // Offscreen canvas doesn't respect the permission.
+      continue;
+    }
     permissionGranted
-      ? is(readback, trueValue, message)
-      : isnot(readback, trueValue, message);
+      ? is(imageData, trueValue, message)
+      : isnot(imageData, trueValue, message);
   }
 
   if (permissionGranted) {
