From 5696f96dbbe9994e7025880bd78057444557ccdf Mon Sep 17 00:00:00 2001
From: vikas soni <vikassoni@chromium.org>
Date: Tue, 01 Sep 2026 13:58:04 -0700
Subject: [PATCH] [GPU Security]: Require initial data for compressed GL SharedImages.

GLCommonImageBackingFactory::CanCreateTexture only ran compressed-format
validation when pixel_data was non-empty, so a compressed SharedImage
could be created with no initial data. Compressed formats are not
color-renderable and therefore cannot be cleared after creation, and
glCompressedTexImage2D does not accept null data for non-zero
dimensions.

Run compressed-format validation unconditionally and require that
pixel_data matches the computed compressed size, which rejects requests
with empty pixel data.

Bug: 536673946
Change-Id: I6c25102d8d10685aadbd993efac0bb6cf5296cd6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/8299334
Commit-Queue: vikas soni <vikassoni@chromium.org>
Reviewed-by: Vasiliy Telezhnikov <vasilyt@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1690102}
---

diff --git a/gpu/command_buffer/service/shared_image/gl_common_image_backing_factory.cc b/gpu/command_buffer/service/shared_image/gl_common_image_backing_factory.cc
index 48fbdfd..f9153cc 100644
--- a/gpu/command_buffer/service/shared_image/gl_common_image_backing_factory.cc
+++ b/gpu/command_buffer/service/shared_image/gl_common_image_backing_factory.cc
@@ -219,62 +219,63 @@
     return false;
   }
 
-  // If we have initial data to upload, ensure it is sized appropriately.
-  if (!pixel_data.empty()) {
-    DCHECK_EQ(format_infos.size(), 1u);
+  if (format_infos[0].is_compressed) {
+    CHECK_EQ(format_infos.size(), 1u);
     const FormatInfo& format_info = format_infos[0];
+    const char* error_message = "unspecified";
+    if (!gles2::ValidateCompressedTexDimensions(
+            target, /*level=*/0, size.width(), size.height(), /*depth=*/1,
+            format_info.image_internal_format, &error_message)) {
+      DVLOG(2) << "CreateSharedImage: "
+                  "ValidateCompressedTexDimensionsFailed with error: "
+               << error_message;
+      return false;
+    }
 
-    if (format_info.is_compressed) {
-      const char* error_message = "unspecified";
-      if (!gles2::ValidateCompressedTexDimensions(
-              target, /*level=*/0, size.width(), size.height(), /*depth=*/1,
-              format_info.image_internal_format, &error_message)) {
-        DVLOG(2) << "CreateSharedImage: "
-                    "ValidateCompressedTexDimensionsFailed with error: "
-                 << error_message;
-        return false;
-      }
+    GLsizei bytes_required = 0;
+    if (!gles2::GetCompressedTexSizeInBytes(
+            /*function_name=*/nullptr, size.width(), size.height(),
+            /*depth=*/1, format_info.image_internal_format, &bytes_required,
+            /*error_state=*/nullptr)) {
+      DVLOG(2) << "CreateSharedImage: Unable to compute required size for "
+                  "initial texture upload.";
+      return false;
+    }
 
-      GLsizei bytes_required = 0;
-      if (!gles2::GetCompressedTexSizeInBytes(
-              /*function_name=*/nullptr, size.width(), size.height(),
-              /*depth=*/1, format_info.image_internal_format, &bytes_required,
-              /*error_state=*/nullptr)) {
-        DVLOG(2) << "CreateSharedImage: Unable to compute required size for "
+    // Compressed textures cannot be cleared so they must be created with
+    // initial pixel data of the correct size.
+    if (bytes_required < 0 ||
+        pixel_data.size() != static_cast<size_t>(bytes_required)) {
+      DVLOG(2) << "CreateSharedImage: Initial data does not have expected "
+                  "size.";
+      return false;
+    }
+  } else if (!pixel_data.empty()) {
+    // If we have initial data to upload, ensure it is sized appropriately.
+    CHECK_EQ(format_infos.size(), 1u);
+    const FormatInfo& format_info = format_infos[0];
+    uint32_t bytes_required;
+    uint32_t unpadded_row_size = 0u;
+    uint32_t padded_row_size = 0u;
+    if (!gles2::GLES2Util::ComputeImageDataSizes(
+            size.width(), size.height(), /*depth=*/1, format_info.gl_format,
+            format_info.gl_type, /*alignment=*/4, &bytes_required,
+            &unpadded_row_size, &padded_row_size)) {
+      LOG(ERROR) << "CreateSharedImage: Unable to compute required size for "
                     "initial texture upload.";
-        return false;
-      }
+      return false;
+    }
 
-      if (bytes_required < 0 ||
-          pixel_data.size() != static_cast<size_t>(bytes_required)) {
-        DVLOG(2) << "CreateSharedImage: Initial data does not have expected "
+    // The GL spec, used in the computation for required bytes in the function
+    // above, assumes no padding is required for the last row in the image.
+    // But the client data does include this padding, so we add it for the
+    // data validation check here.
+    uint32_t padding = padded_row_size - unpadded_row_size;
+    bytes_required += padding;
+    if (pixel_data.size() != bytes_required) {
+      LOG(ERROR) << "CreateSharedImage: Initial data does not have expected "
                     "size.";
-        return false;
-      }
-    } else {
-      uint32_t bytes_required;
-      uint32_t unpadded_row_size = 0u;
-      uint32_t padded_row_size = 0u;
-      if (!gles2::GLES2Util::ComputeImageDataSizes(
-              size.width(), size.height(), /*depth=*/1, format_info.gl_format,
-              format_info.gl_type, /*alignment=*/4, &bytes_required,
-              &unpadded_row_size, &padded_row_size)) {
-        LOG(ERROR) << "CreateSharedImage: Unable to compute required size for "
-                      "initial texture upload.";
-        return false;
-      }
-
-      // The GL spec, used in the computation for required bytes in the function
-      // above, assumes no padding is required for the last row in the image.
-      // But the client data does include this padding, so we add it for the
-      // data validation check here.
-      uint32_t padding = padded_row_size - unpadded_row_size;
-      bytes_required += padding;
-      if (pixel_data.size() != bytes_required) {
-        LOG(ERROR) << "CreateSharedImage: Initial data does not have expected "
-                      "size.";
-        return false;
-      }
+      return false;
     }
   }
 
diff --git a/gpu/command_buffer/service/shared_image/gl_texture_image_backing_factory_unittest.cc b/gpu/command_buffer/service/shared_image/gl_texture_image_backing_factory_unittest.cc
index 94139b6c..13f1050 100644
--- a/gpu/command_buffer/service/shared_image/gl_texture_image_backing_factory_unittest.cc
+++ b/gpu/command_buffer/service/shared_image/gl_texture_image_backing_factory_unittest.cc
@@ -167,6 +167,33 @@
 using GLTextureImageBackingFactoryWithReadbackTest =
     GLTextureImageBackingFactoryWithUploadTest;
 
+TEST_F(GLTextureImageBackingFactoryTest, CompressedFormatRequiresInitialData) {
+  if (!supports_etc1_) {
+    GTEST_SKIP();
+  }
+
+  auto format = viz::SinglePlaneFormat::kETC1;
+  gfx::Size size(64, 64);
+  // Note: The specific usage doesn't matter here as long as it's supported by
+  // GLTextureImageBacking.
+  gpu::SharedImageUsageSet usage = SHARED_IMAGE_USAGE_GLES2_READ;
+
+  // Compressed textures cannot be cleared so they must be created with initial
+  // pixel data.
+  bool supported = backing_factory_->CanCreateSharedImage(
+      usage, format, size, /*thread_safe=*/false, gfx::EMPTY_BUFFER,
+      GrContextType::kGL, {});
+  EXPECT_FALSE(supported);
+
+  // With correctly sized initial data the format is supported.
+  size_t required_size = format.MaybeEstimatedSizeInBytes(size).value();
+  std::vector<uint8_t> initial_data(required_size);
+  supported = backing_factory_->CanCreateSharedImage(
+      usage, format, size, /*thread_safe=*/false, gfx::EMPTY_BUFFER,
+      GrContextType::kGL, initial_data);
+  EXPECT_TRUE(supported);
+}
+
 TEST_F(GLTextureImageBackingFactoryTest, InvalidFormat) {
   auto format = viz::SinglePlaneFormat::kBGR_565;
   gfx::Size size(256, 256);

diff --git a/gpu/command_buffer/service/shared_image/gl_texture_image_backing_factory_unittest.cc b/gpu/command_buffer/service/shared_image/gl_texture_image_backing_factory_unittest.cc
index 94139b6c..13f1050 100644
--- a/gpu/command_buffer/service/shared_image/gl_texture_image_backing_factory_unittest.cc
+++ b/gpu/command_buffer/service/shared_image/gl_texture_image_backing_factory_unittest.cc
@@ -167,6 +167,33 @@
 using GLTextureImageBackingFactoryWithReadbackTest =
     GLTextureImageBackingFactoryWithUploadTest;
 
+TEST_F(GLTextureImageBackingFactoryTest, CompressedFormatRequiresInitialData) {
+  if (!supports_etc1_) {
+    GTEST_SKIP();
+  }
+
+  auto format = viz::SinglePlaneFormat::kETC1;
+  gfx::Size size(64, 64);
+  // Note: The specific usage doesn't matter here as long as it's supported by
+  // GLTextureImageBacking.
+  gpu::SharedImageUsageSet usage = SHARED_IMAGE_USAGE_GLES2_READ;
+
+  // Compressed textures cannot be cleared so they must be created with initial
+  // pixel data.
+  bool supported = backing_factory_->CanCreateSharedImage(
+      usage, format, size, /*thread_safe=*/false, gfx::EMPTY_BUFFER,
+      GrContextType::kGL, {});
+  EXPECT_FALSE(supported);
+
+  // With correctly sized initial data the format is supported.
+  size_t required_size = format.MaybeEstimatedSizeInBytes(size).value();
+  std::vector<uint8_t> initial_data(required_size);
+  supported = backing_factory_->CanCreateSharedImage(
+      usage, format, size, /*thread_safe=*/false, gfx::EMPTY_BUFFER,
+      GrContextType::kGL, initial_data);
+  EXPECT_TRUE(supported);
+}
+
 TEST_F(GLTextureImageBackingFactoryTest, InvalidFormat) {
   auto format = viz::SinglePlaneFormat::kBGR_565;
   gfx::Size size(256, 256);