Improve update request privacy (#31127)

* Don't send any contents of the hw object
 * Never send app/lang
 * Don't send download_time_ms

The motivation is that these could otherwise potentially be used to
fingerprint users.

BUILD.gn

@@ -87,6 +87,9 @@ if (!is_ios) {
 if (!is_ios && !is_android) {
   brave_all_unit_tests_deps += [ "//brave/test:brave_installer_unittests" ]
 }
+if (is_win || is_mac || is_linux) {
+  brave_all_unit_tests_deps += [ "//brave/updater:brave_updater_unittests" ]
+}
 
 # This group is for unit tests that run as part of brave_all_unit_tests. Other
 # tests that you only want to build should be added directly to `all` group

DEPS

@@ -98,7 +98,7 @@ hooks = [
     'pattern': '.',
     'condition': 'checkout_mac',
     'action': ['vpython3', 'build/download_dep.py',
-               'omaha4/BraveUpdater-136.1.79.71.zip',
+               'omaha4/BraveUpdater-141.1.84.102.zip',
                '//brave/third_party/updater/mac',
                'BraveUpdater.app/'],
   },

chromium_src/chrome/updater/DEPS

@@ -0,0 +1,3 @@
+include_rules = [
+  "+brave/components/update_client/privacy_preserving_protocol_handler.h",
+]

chromium_src/chrome/updater/configurator.cc

@@ -0,0 +1,10 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "brave/components/update_client/privacy_preserving_protocol_handler.h"
+
+#define ProtocolHandlerFactoryJSON PrivacyPreservingProtocolHandlerFactory
+#include <chrome/updater/configurator.cc>
+#undef ProtocolHandlerFactoryJSON

chromium_src/chrome/updater/ping_configurator.cc

@@ -0,0 +1,10 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "brave/components/update_client/privacy_preserving_protocol_handler.h"
+
+#define ProtocolHandlerFactoryJSON PrivacyPreservingProtocolHandlerFactory
+#include <chrome/updater/ping_configurator.cc>
+#undef ProtocolHandlerFactoryJSON

chromium_src/components/component_updater/DEPS

@@ -1,4 +1,5 @@
 include_rules = [
+  "+brave/components/update_client/privacy_preserving_protocol_handler.h",
   "+components/crx_file",
   "+components/update_client",
 ]

chromium_src/components/component_updater/configurator_impl.cc

@@ -5,9 +5,13 @@
 
 #include "components/component_updater/configurator_impl.h"
 
+#include "brave/components/update_client/privacy_preserving_protocol_handler.h"
+
 #define EnabledBackgroundDownloader EnabledBackgroundDownloader_Unused
 #define EnabledCupSigning EnabledCupSigning_Unused
+#define ProtocolHandlerFactoryJSON PrivacyPreservingProtocolHandlerFactory
 #include <components/component_updater/configurator_impl.cc>
+#undef ProtocolHandlerFactoryJSON
 #undef EnabledCupSigning
 #undef EnabledBackgroundDownloader
 

components/BUILD.gn

@@ -31,9 +31,11 @@ test("brave_components_unittests") {
     "//brave/components/brave_shields/core/browser:unit_tests",
     "//brave/components/brave_shields/core/common:unit_tests",
     "//brave/components/brave_wallet/common:unit_tests",
+    "//brave/components/component_updater:unit_tests",
     "//brave/components/email_aliases:unit_tests",
     "//brave/components/json:unit_tests",
     "//brave/components/static_redirect_helper:unit_tests",
+    "//brave/components/update_client:unit_tests",
     "//components/test:run_all_unittests",
   ]
 

components/component_updater/BUILD.gn

@@ -0,0 +1,16 @@
+# Copyright (c) 2025 The Brave Authors. All rights reserved.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at https://mozilla.org/MPL/2.0/.
+
+source_set("unit_tests") {
+  testonly = true
+  sources = [ "configurator_impl_unittest.cc" ]
+  deps = [
+    "//base",
+    "//brave/components/update_client:test_util",
+    "//components/component_updater",
+    "//components/update_client",
+    "//testing/gtest",
+  ]
+}

components/component_updater/DEPS

@@ -0,0 +1,4 @@
+include_rules = [
+  "+components/component_updater",
+  "+components/update_client",
+]

components/component_updater/configurator_impl_unittest.cc

@@ -0,0 +1,30 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "components/component_updater/configurator_impl.h"
+
+#include "brave/components/update_client/test_util.h"
+#include "components/update_client/command_line_config_policy.h"
+#include "components/update_client/protocol_handler.h"
+#include "components/update_client/protocol_serializer.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace component_updater {
+
+TEST(BraveComponentUpdaterConfiguratorImplTest,
+     UsesPrivacyPreservingProtocolSerializer) {
+  auto configurator = std::make_unique<ConfiguratorImpl>(
+      update_client::CommandLineConfigPolicy(), false);
+
+  auto factory = configurator->GetProtocolHandlerFactory();
+  ASSERT_TRUE(factory);
+
+  auto serializer = factory->CreateSerializer();
+  ASSERT_TRUE(serializer);
+
+  EXPECT_TRUE(update_client::StripsPrivacySensitiveData(*serializer));
+}
+
+}  // namespace component_updater

components/update_client/BUILD.gn

@@ -22,3 +22,31 @@ buildflag_header("buildflags") {
     "UPDATER_PROD_ENDPOINT=\"$updater_prod_endpoint\"",
   ]
 }
+
+source_set("unit_tests") {
+  testonly = true
+  sources = [ "privacy_preserving_protocol_handler_unittest.cc" ]
+  deps = [
+    ":test_util",
+    "//components/update_client",
+    "//testing/gtest",
+
+    # The build fails without this dep, even though our source doesn't use it.
+    "//base",
+  ]
+}
+
+source_set("test_util") {
+  testonly = true
+  sources = [
+    "test_util.cc",
+    "test_util.h",
+  ]
+  deps = [
+    "//base",
+    "//components/prefs",
+    "//components/prefs:test_support",
+    "//components/update_client",
+    "//third_party/re2",
+  ]
+}

components/update_client/DEPS

@@ -0,0 +1,10 @@
+include_rules = [
+  "+components/update_client",
+]
+specific_include_rules = {
+  "test_util.cc": [
+    "+components/prefs/pref_service.h",
+    "+components/prefs/testing_pref_service.h",
+    "+third_party/re2",
+  ]
+}

components/update_client/privacy_preserving_protocol_handler.cc

@@ -0,0 +1,27 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "brave/components/update_client/privacy_preserving_protocol_handler.h"
+
+#include <memory>
+
+#include "brave/components/update_client/privacy_preserving_protocol_serializer.h"
+#include "components/update_client/protocol_handler.h"
+#include "components/update_client/protocol_parser.h"
+
+namespace update_client {
+
+std::unique_ptr<ProtocolParser>
+PrivacyPreservingProtocolHandlerFactory::CreateParser() const {
+  // We're not interested in changing this behavior. Mirror upstream.
+  return ProtocolHandlerFactoryJSON().CreateParser();
+}
+
+std::unique_ptr<ProtocolSerializer>
+PrivacyPreservingProtocolHandlerFactory::CreateSerializer() const {
+  return std::make_unique<PrivacyPreservingProtocolSerializer>();
+}
+
+}  // namespace update_client

components/update_client/privacy_preserving_protocol_handler.h

@@ -0,0 +1,29 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#ifndef BRAVE_COMPONENTS_UPDATE_CLIENT_PRIVACY_PRESERVING_PROTOCOL_HANDLER_H_
+#define BRAVE_COMPONENTS_UPDATE_CLIENT_PRIVACY_PRESERVING_PROTOCOL_HANDLER_H_
+
+#include <memory>
+
+#include "components/update_client/protocol_handler.h"
+#include "components/update_client/protocol_parser.h"
+#include "components/update_client/protocol_serializer.h"
+
+namespace update_client {
+
+// This class returns the same parser as upstream but returns a different
+// serializer (PrivacyPreservingProtocolSerializer) to remove values from update
+// requests that could be used to fingerprint users.
+class PrivacyPreservingProtocolHandlerFactory : public ProtocolHandlerFactory {
+ public:
+  // Overrides for ProtocolHandlerFactory.
+  std::unique_ptr<ProtocolParser> CreateParser() const override;
+  std::unique_ptr<ProtocolSerializer> CreateSerializer() const override;
+};
+
+}  // namespace update_client
+
+#endif  // BRAVE_COMPONENTS_UPDATE_CLIENT_PRIVACY_PRESERVING_PROTOCOL_HANDLER_H_

components/update_client/privacy_preserving_protocol_handler_unittest.cc

@@ -0,0 +1,17 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "brave/components/update_client/privacy_preserving_protocol_serializer.h"
+#include "brave/components/update_client/test_util.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace update_client {
+
+TEST(PrivacyPreservingProtocolSerializer, StripsPrivacySensitiveData) {
+  EXPECT_TRUE(
+      StripsPrivacySensitiveData(PrivacyPreservingProtocolSerializer()));
+}
+
+}  // namespace update_client

components/update_client/privacy_preserving_protocol_serializer.cc

@@ -0,0 +1,65 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "brave/components/update_client/privacy_preserving_protocol_serializer.h"
+
+#include <string>
+#include <utility>
+
+#include "base/json/json_reader.h"
+#include "base/json/json_writer.h"
+#include "base/values.h"
+#include "components/update_client/protocol_definition.h"
+#include "components/update_client/protocol_serializer_json.h"
+
+namespace update_client {
+
+// This method returns the same result as upstream's ProtocolSerializerJSON,
+// but with some fields removed that could be used to fingerprint users.
+std::string PrivacyPreservingProtocolSerializer::Serialize(
+    const protocol_request::Request& request) const {
+  std::string upstream_result = ProtocolSerializerJSON().Serialize(request);
+  std::optional<base::Value> root = base::JSONReader::Read(upstream_result);
+  if (!root.has_value() || !root->is_dict()) {
+    return upstream_result;
+  }
+
+  base::Value::Dict& root_dict = root->GetDict();
+  base::Value::Dict* request_dict = root_dict.FindDict("request");
+  if (!request_dict) {
+    return upstream_result;
+  }
+
+  // We don't want to send the information in the hw dictionary, but the
+  // protocol specification requires it to be present. All its fields have
+  // default values and are therefore optional. We therefore remain
+  // spec-compliant by simply sending an empty hw dictionary.
+  if (base::Value::Dict* hw_dict = request_dict->FindDict("hw")) {
+    hw_dict->clear();
+  }
+
+  if (base::Value::List* apps = request_dict->FindList("apps")) {
+    for (auto& app : *apps) {
+      if (!app.is_dict()) {
+        continue;
+      }
+
+      base::Value::Dict& app_dict = app.GetDict();
+      app_dict.Remove("lang");
+
+      if (base::Value::List* events = app_dict.FindList("events")) {
+        for (auto& event : *events) {
+          if (event.is_dict()) {
+            event.GetDict().Remove("download_time_ms");
+          }
+        }
+      }
+    }
+  }
+
+  return base::WriteJson(*root).value_or(std::move(upstream_result));
+}
+
+}  // namespace update_client

components/update_client/privacy_preserving_protocol_serializer.h

@@ -0,0 +1,34 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#ifndef BRAVE_COMPONENTS_UPDATE_CLIENT_PRIVACY_PRESERVING_PROTOCOL_SERIALIZER_H_
+#define BRAVE_COMPONENTS_UPDATE_CLIENT_PRIVACY_PRESERVING_PROTOCOL_SERIALIZER_H_
+
+#include <string>
+
+#include "components/update_client/protocol_definition.h"
+#include "components/update_client/protocol_serializer.h"
+
+namespace update_client {
+// PrivacyPreservingProtocolSerializer wraps around upstream's
+// ProtocolSerializerJSON, removing values from update requests that could be
+// used to fingerprint users.
+class PrivacyPreservingProtocolSerializer : public ProtocolSerializer {
+ public:
+  PrivacyPreservingProtocolSerializer() = default;
+
+  PrivacyPreservingProtocolSerializer(
+      const PrivacyPreservingProtocolSerializer&) = delete;
+  PrivacyPreservingProtocolSerializer& operator=(
+      const PrivacyPreservingProtocolSerializer&) = delete;
+
+  // Overrides for ProtocolSerializer.
+  std::string Serialize(
+      const protocol_request::Request& request) const override;
+};
+
+}  // namespace update_client
+
+#endif  // BRAVE_COMPONENTS_UPDATE_CLIENT_PRIVACY_PRESERVING_PROTOCOL_SERIALIZER_H_

components/update_client/sources.gni

@@ -3,6 +3,13 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this file,
 # You can obtain one at http://mozilla.org/MPL/2.0/.
 
+brave_components_update_client_sources = [
+  "//brave/components/update_client/privacy_preserving_protocol_handler.cc",
+  "//brave/components/update_client/privacy_preserving_protocol_handler.h",
+  "//brave/components/update_client/privacy_preserving_protocol_serializer.cc",
+  "//brave/components/update_client/privacy_preserving_protocol_serializer.h",
+]
+
 brave_components_update_client_deps = [
   "//brave/components/constants",
   "//brave/components/widevine:constants",

components/update_client/test_util.cc

@@ -0,0 +1,86 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "brave/components/update_client/test_util.h"
+
+#include <memory>
+#include <optional>
+#include <utility>
+#include <vector>
+
+#include "base/functional/bind.h"
+#include "base/values.h"
+#include "base/version.h"
+#include "components/prefs/pref_service.h"
+#include "components/prefs/testing_pref_service.h"
+#include "components/update_client/persisted_data.h"
+#include "components/update_client/protocol_definition.h"
+#include "components/update_client/protocol_serializer.h"
+#include "third_party/re2/src/re2/re2.h"
+
+namespace update_client {
+
+// This function checks two things. First, that the serializer faithfully
+// encodes the necessary data for update requests. Second, that it does not
+// encode the following fields, which could be used to fingerprint users:
+//  - hw[*]
+//  - apps[*].lang
+//  - apps[*].events[*].download_time_ms
+bool StripsPrivacySensitiveData(const ProtocolSerializer& serializer) {
+  // Much of this code was copied from protocol_serializer_json_unittest.cc.
+  auto pref = std::make_unique<TestingPrefServiceSimple>();
+  RegisterPersistedDataPrefs(pref->registry());
+  auto metadata = CreatePersistedData(
+      base::BindRepeating([](PrefService* pref) { return pref; }, pref.get()),
+      nullptr);
+
+  std::vector<base::Value::Dict> events(2);
+  events[0].Set("download_time_ms", 9965);
+  events[0].Set("eventresult", 1);
+  events[1].Set("eventtype", 63);
+
+  std::vector<protocol_request::App> apps;
+  apps.push_back(MakeProtocolApp(
+      "id1", base::Version("1.0"), "ap1", "BRND", "ins_id", "lang", -1,
+      "source1", "location1", {{"attr", "1"}}, "c1", "ch1", "cn1", "test",
+      {9384}, /*cached_hashes=*/{},
+      MakeProtocolUpdateCheck(true, "33.12", true, false),
+      {{"install", "foobar_install_data_index", ""}},
+      MakeProtocolPing("id1", metadata.get(), {}), std::move(events)));
+
+  const auto request = MakeProtocolRequest(
+      false, "{15160585-8ADE-4D3C-839B-1281A6035D1F}", "prod_id", "1.0",
+      "channel", "OS", "cacheable", std::nullopt, {{"extra", "params"}}, {},
+      std::move(apps));
+
+  const auto request_str = serializer.Serialize(request);
+  static constexpr char regex[] =
+      R"({"request":{"@os":"\w+","@updater":"prod_id",)"
+      R"("acceptformat":"[^"]+",)"
+      R"("apps":\[{"ap":"ap1","appid":"id1","attr":"1",)"
+      R"("brand":"BRND","cohort":"c1","cohorthint":"ch1","cohortname":"cn1",)"
+      R"("data":\[{"index":"foobar_install_data_index","name":"install"}],)"
+      R"("disabled":\[{"reason":9384}],"enabled":false,)"
+      R"("events":\[{"eventresult":1},{"eventtype":63}],)"
+      R"("iid":"ins_id",)"
+      R"("installdate":-1,)"
+      R"("installedby":"location1","installsource":"source1",)"
+      R"("ping":{[^}]*},)"
+      R"("release_channel":"test",)"
+      R"("updatecheck":{"rollback_allowed":true,)"
+      R"("targetversionprefix":"33.12",)"
+      R"("updatedisabled":true},"version":"1.0"}],"arch":"\w+","dedup":"cr",)"
+      R"("dlpref":"cacheable","extra":"params",)"
+      R"("hw":{},)"
+      R"("ismachine":false,)"
+      R"("os":{"arch":"[_,-.\w]+","platform":"OS",)"
+      R"(("sp":"[\s\w]+",)?"version":"[+-.\w]+"},"prodchannel":"channel",)"
+      R"("prodversion":"1.0","protocol":"4.0","requestid":"{[-\w]{36}}",)"
+      R"("sessionid":"{[-\w]{36}}","updaterchannel":"channel",)"
+      R"("updaterversion":"1.0"(,"wow64":true)?}})";
+  return RE2::FullMatch(request_str, regex);
+}
+
+}  // namespace update_client

components/update_client/test_util.h

@@ -0,0 +1,17 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#ifndef BRAVE_COMPONENTS_UPDATE_CLIENT_TEST_UTIL_H_
+#define BRAVE_COMPONENTS_UPDATE_CLIENT_TEST_UTIL_H_
+
+#include "components/update_client/protocol_serializer.h"
+
+namespace update_client {
+
+bool StripsPrivacySensitiveData(const ProtocolSerializer& serializer);
+
+}  // namespace update_client
+
+#endif  // BRAVE_COMPONENTS_UPDATE_CLIENT_TEST_UTIL_H_

patches/components-update_client-BUILD.gn.patch

@@ -1,12 +1,12 @@
 diff --git a/components/update_client/BUILD.gn b/components/update_client/BUILD.gn
-index a0f35874277a25cb7d091dafa54730915962439d..d15b797053c03a1c2d192d12158c2524d09510f7 100644
+index a0f35874277a25cb7d091dafa54730915962439d..fb179a65da5712323ea1df316a5653706db55f1b 100644
 --- a/components/update_client/BUILD.gn
 +++ b/components/update_client/BUILD.gn
 @@ -199,6 +199,7 @@ static_library("update_client") {
        "background_downloader_win.h",
      ]
    }
-+  deps += brave_components_update_client_deps public_deps = brave_components_update_client_public_deps
++  sources += brave_components_update_client_sources deps += brave_components_update_client_deps public_deps = brave_components_update_client_public_deps
  }
  
  if (is_mac) {

updater/BUILD.gn

@@ -0,0 +1,27 @@
+# Copyright (c) 2025 The Brave Authors. All rights reserved.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at https://mozilla.org/MPL/2.0/.
+
+import("//testing/test.gni")
+
+if (is_win || is_mac || is_linux) {
+  test("brave_updater_unittests") {
+    testonly = true
+    sources = [
+      "configurator_unittest.cc",
+      "ping_configurator_unittest.cc",
+      "run_all_unittests.cc",
+    ]
+    deps = [
+      "//base",
+      "//base/test:test_support",
+      "//brave/components/update_client:test_util",
+      "//chrome/updater:base",
+      "//chrome/updater:constants_test",
+      "//components/prefs:test_support",
+      "//components/update_client",
+      "//testing/gtest",
+    ]
+  }
+}

updater/DEPS

@@ -0,0 +1,6 @@
+include_rules = [
+  "+brave/components/update_client",
+  "+chrome/updater",
+  "+components/prefs",
+  "+components/update_client",
+]

updater/configurator_unittest.cc

@@ -0,0 +1,49 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "chrome/updater/configurator.h"
+
+#include <utility>
+
+#include "base/files/file_path.h"
+#include "base/memory/scoped_refptr.h"
+#include "base/test/task_environment.h"
+#include "brave/components/update_client/test_util.h"
+#include "chrome/updater/external_constants.h"
+#include "chrome/updater/persisted_data.h"
+#include "chrome/updater/prefs_impl.h"
+#include "chrome/updater/updater_scope.h"
+#include "components/prefs/pref_registry_simple.h"
+#include "components/prefs/testing_pref_service.h"
+#include "components/update_client/protocol_handler.h"
+#include "components/update_client/protocol_serializer.h"
+#include "components/update_client/update_client.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace updater {
+
+TEST(Configurator, UsesPrivacyPreservingProtocolSerializer) {
+  base::test::TaskEnvironment task_environment;
+
+  auto pref_service = std::make_unique<TestingPrefServiceSimple>();
+  update_client::RegisterPrefs(pref_service->registry());
+  RegisterPersistedDataPrefs(pref_service->registry());
+
+  auto prefs = base::MakeRefCounted<UpdaterPrefsImpl>(base::FilePath(), nullptr,
+                                                      std::move(pref_service));
+  auto external_constants = CreateExternalConstants();
+
+  auto configurator = base::MakeRefCounted<Configurator>(
+      prefs, external_constants, UpdaterScope::kUser);
+  auto factory = configurator->GetProtocolHandlerFactory();
+  ASSERT_TRUE(factory);
+
+  auto serializer = factory->CreateSerializer();
+  ASSERT_TRUE(serializer);
+
+  EXPECT_TRUE(update_client::StripsPrivacySensitiveData(*serializer));
+}
+
+}  // namespace updater

updater/ping_configurator_unittest.cc

@@ -0,0 +1,27 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "chrome/updater/ping_configurator.h"
+
+#include "brave/components/update_client/test_util.h"
+#include "components/update_client/protocol_handler.h"
+#include "components/update_client/protocol_serializer.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace updater {
+
+TEST(PingConfigurator, UsesPrivacyPreservingProtocolSerializer) {
+  auto configurator = CreatePingConfigurator();
+
+  auto factory = configurator->GetProtocolHandlerFactory();
+  ASSERT_TRUE(factory);
+
+  auto serializer = factory->CreateSerializer();
+  ASSERT_TRUE(serializer);
+
+  EXPECT_TRUE(update_client::StripsPrivacySensitiveData(*serializer));
+}
+
+}  // namespace updater

updater/run_all_unittests.cc

@@ -0,0 +1,15 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "base/functional/bind.h"
+#include "base/test/launcher/unit_test_launcher.h"
+#include "base/test/test_suite.h"
+
+int main(int argc, char** argv) {
+  base::TestSuite test_suite(argc, argv);
+  return base::LaunchUnitTests(
+      argc, argv,
+      base::BindOnce(&base::TestSuite::Run, base::Unretained(&test_suite)));
+}