[Sync] Share helpers for explicit passphrase mojo between Ash and Lacros

This CL intoduces "chromeos" subfolder under components/sync, moves
there functions for conversions between Nigori and its mojo
representation, that used to be duplicated in Ash and Lacros, and adds
test coverage for them.

Bug: 1233545
Change-Id: I4174ed10b0e07090d8567b6727fc06b72a995ed9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3568461
Reviewed-by: Marc Treib <treib@chromium.org>
Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Commit-Queue: Maksim Moskvitin <mmoskvitin@google.com>
Cr-Commit-Position: refs/heads/main@{#989467}

chrome/browser/ash/sync/sync_explicit_passphrase_client_ash.cc

@@ -12,6 +12,7 @@
 #include "components/account_manager_core/account.h"
 #include "components/account_manager_core/account_manager_util.h"
 #include "components/signin/public/identity_manager/account_info.h"
+#include "components/sync/chromeos/explicit_passphrase_mojo_utils.h"
 #include "components/sync/driver/sync_user_settings.h"
 #include "components/sync/engine/nigori/nigori.h"
 #include "third_party/abseil-cpp/absl/types/optional.h"
@@ -20,41 +21,13 @@ namespace ash {
 
 namespace {
 
-crosapi::mojom::NigoriKeyPtr NigoriToMojo(const syncer::Nigori& nigori) {
-  std::string deprecated_user_key;
-  std::string encryption_key;
-  std::string mac_key;
-  nigori.ExportKeys(&deprecated_user_key, &encryption_key, &mac_key);
-
-  crosapi::mojom::NigoriKeyPtr mojo_result = crosapi::mojom::NigoriKey::New();
-  mojo_result->encryption_key =
-      std::vector<uint8_t>(encryption_key.begin(), encryption_key.end());
-  mojo_result->mac_key = std::vector<uint8_t>(mac_key.begin(), mac_key.end());
-  return mojo_result;
-}
-
-std::unique_ptr<syncer::Nigori> NigoriFromMojo(
-    const crosapi::mojom::NigoriKey& mojo_key) {
-  const std::string encryption_key(mojo_key.encryption_key.begin(),
-                                   mojo_key.encryption_key.end());
-  const std::string mac_key(mojo_key.mac_key.begin(), mojo_key.mac_key.end());
-  // |user_key| is deprecated, it's safe to pass empty string.
-  return syncer::Nigori::CreateByImport(
-      /*user_key=*/std::string(), encryption_key, mac_key);
-}
-
 bool IsPassphraseAvailable(const syncer::SyncService& sync_service) {
   return sync_service.GetUserSettings()->IsUsingExplicitPassphrase() &&
          !sync_service.GetUserSettings()->IsPassphraseRequired();
 }
 
 }  // namespace
 
-crosapi::mojom::NigoriKeyPtr NigoriToMojoForTesting(  // IN-TEST
-    const syncer::Nigori& nigori) {
-  return NigoriToMojo(nigori);
-}
-
 SyncExplicitPassphraseClientAsh::SyncExplicitPassphraseClientAsh(
     syncer::SyncService* sync_service)
     : sync_service_(sync_service),
@@ -104,7 +77,7 @@ void SyncExplicitPassphraseClientAsh::GetDecryptionNigoriKey(
     return;
   }
 
-  std::move(callback).Run(NigoriToMojo(*decryption_key));
+  std::move(callback).Run(syncer::NigoriToMojo(*decryption_key));
 }
 
 void SyncExplicitPassphraseClientAsh::SetDecryptionNigoriKey(
@@ -114,7 +87,8 @@ void SyncExplicitPassphraseClientAsh::SetDecryptionNigoriKey(
     return;
   }
 
-  std::unique_ptr<syncer::Nigori> nigori_key = NigoriFromMojo(*mojo_nigori_key);
+  std::unique_ptr<syncer::Nigori> nigori_key =
+      syncer::NigoriFromMojo(*mojo_nigori_key);
   if (!nigori_key) {
     // Deserialization failed, |mojo_nigori_key| doesn't represent an actual
     // Nigori key.

chrome/browser/ash/sync/sync_explicit_passphrase_client_ash.h

@@ -14,10 +14,6 @@
 #include "mojo/public/cpp/bindings/receiver_set.h"
 #include "mojo/public/cpp/bindings/remote_set.h"
 
-namespace syncer {
-class Nigori;
-}
-
 namespace ash {
 
 class SyncExplicitPassphraseClientAsh
@@ -69,9 +65,6 @@ class SyncExplicitPassphraseClientAsh
       observers_;
 };
 
-crosapi::mojom::NigoriKeyPtr NigoriToMojoForTesting(
-    const syncer::Nigori& nigori);
-
 }  // namespace ash
 
 #endif  // CHROME_BROWSER_ASH_SYNC_SYNC_EXPLICIT_PASSPHRASE_CLIENT_ASH_H_

chrome/browser/ash/sync/sync_explicit_passphrase_client_ash_unittest.cc

@@ -6,6 +6,7 @@
 
 #include "base/test/task_environment.h"
 #include "chromeos/crosapi/mojom/sync.mojom-test-utils.h"
+#include "components/sync/chromeos/explicit_passphrase_mojo_utils.h"
 #include "components/sync/driver/mock_sync_service.h"
 #include "components/sync/driver/sync_user_settings_mock.h"
 #include "components/sync/engine/nigori/key_derivation_params.h"
@@ -28,7 +29,7 @@ std::unique_ptr<syncer::Nigori> MakeTestNigoriKey() {
 
 crosapi::mojom::NigoriKeyPtr MakeTestMojoNigoriKey() {
   std::unique_ptr<syncer::Nigori> nigori_key = MakeTestNigoriKey();
-  return NigoriToMojoForTesting(*nigori_key);
+  return syncer::NigoriToMojo(*nigori_key);
 }
 
 class TestSyncExplicitPassphraseClientObserver

chrome/browser/lacros/sync/sync_explicit_passphrase_client_lacros.cc

@@ -9,56 +9,28 @@
 #include "components/account_manager_core/account.h"
 #include "components/account_manager_core/account_manager_util.h"
 #include "components/signin/public/identity_manager/account_info.h"
+#include "components/sync/chromeos/explicit_passphrase_mojo_utils.h"
 #include "components/sync/driver/sync_service.h"
 #include "components/sync/driver/sync_user_settings.h"
 #include "components/sync/engine/nigori/nigori.h"
 
 namespace {
 
-// TODO(crbug.com/1233545): Move common parts of Ash and Lacros implementation
-// somewhere under components/ and reuse them (mojo utils, test helpers, maybe
-// observer of the sync service).
 crosapi::mojom::AccountKeyPtr GetMojoAccountKey(
     const syncer::SyncService& sync_service) {
   return account_manager::ToMojoAccountKey(account_manager::AccountKey(
       sync_service.GetAccountInfo().gaia, account_manager::AccountType::kGaia));
 }
 
-crosapi::mojom::NigoriKeyPtr NigoriToMojo(const syncer::Nigori& nigori) {
-  std::string deprecated_user_key;
-  std::string encryption_key;
-  std::string mac_key;
-  nigori.ExportKeys(&deprecated_user_key, &encryption_key, &mac_key);
-
-  crosapi::mojom::NigoriKeyPtr mojo_result = crosapi::mojom::NigoriKey::New();
-  mojo_result->encryption_key =
-      std::vector<uint8_t>(encryption_key.begin(), encryption_key.end());
-  mojo_result->mac_key = std::vector<uint8_t>(mac_key.begin(), mac_key.end());
-  return mojo_result;
-}
-
-std::unique_ptr<syncer::Nigori> NigoriFromMojo(
-    const crosapi::mojom::NigoriKey& mojo_key) {
-  const std::string encryption_key(mojo_key.encryption_key.begin(),
-                                   mojo_key.encryption_key.end());
-  const std::string mac_key(mojo_key.mac_key.begin(), mojo_key.mac_key.end());
-  // |user_key| is deprecated, it's safe to pass empty string.
-  return syncer::Nigori::CreateByImport(
-      /*user_key=*/std::string(), encryption_key, mac_key);
-}
-
 bool IsPassphraseAvailable(const syncer::SyncService& sync_service) {
   return sync_service.GetUserSettings()->IsUsingExplicitPassphrase() &&
          !sync_service.GetUserSettings()->IsPassphraseRequired();
 }
 
 }  // namespace
 
-crosapi::mojom::NigoriKeyPtr NigoriToMojoForTesting(  // IN-TEST
-    const syncer::Nigori& nigori) {
-  return NigoriToMojo(nigori);
-}
-
+// TODO(crbug.com/1233545): Consider sharing sync service observer logic between
+// Ash and Lacros.
 SyncExplicitPassphraseClientLacros::LacrosSyncServiceObserver::
     LacrosSyncServiceObserver(
         syncer::SyncService* sync_service,
@@ -208,7 +180,7 @@ void SyncExplicitPassphraseClientLacros::SendDecryptionKeyToAsh() {
     return;
   }
   remote_->SetDecryptionNigoriKey(GetMojoAccountKey(*sync_service_),
-                                  NigoriToMojo(*decryption_key));
+                                  syncer::NigoriToMojo(*decryption_key));
 }
 
 void SyncExplicitPassphraseClientLacros::OnQueryDecryptionKeyFromAshCompleted(
@@ -218,7 +190,8 @@ void SyncExplicitPassphraseClientLacros::OnQueryDecryptionKeyFromAshCompleted(
     return;
   }
 
-  std::unique_ptr<syncer::Nigori> nigori_key = NigoriFromMojo(*mojo_nigori_key);
+  std::unique_ptr<syncer::Nigori> nigori_key =
+      syncer::NigoriFromMojo(*mojo_nigori_key);
   if (!nigori_key) {
     // Deserialization failed, |mojo_nigori_key| doesn't represent an actual
     // Nigori key.

chrome/browser/lacros/sync/sync_explicit_passphrase_client_lacros.h

@@ -14,7 +14,6 @@
 #include "mojo/public/cpp/bindings/remote.h"
 
 namespace syncer {
-class Nigori;
 class SyncService;
 }  // namespace syncer
 
@@ -113,7 +112,4 @@ class SyncExplicitPassphraseClientLacros {
   mojo::Remote<crosapi::mojom::SyncExplicitPassphraseClient> remote_;
 };
 
-crosapi::mojom::NigoriKeyPtr NigoriToMojoForTesting(
-    const syncer::Nigori& nigori);
-
 #endif  // CHROME_BROWSER_LACROS_SYNC_SYNC_EXPLICIT_PASSPHRASE_CLIENT_LACROS_H_

chrome/browser/lacros/sync/sync_explicit_passphrase_client_lacros_unittest.cc

@@ -10,6 +10,7 @@
 #include "components/account_manager_core/account.h"
 #include "components/account_manager_core/account_manager_util.h"
 #include "components/signin/public/identity_manager/account_info.h"
+#include "components/sync/chromeos/explicit_passphrase_mojo_utils.h"
 #include "components/sync/driver/mock_sync_service.h"
 #include "components/sync/driver/sync_service_observer.h"
 #include "components/sync/driver/sync_user_settings_mock.h"
@@ -33,7 +34,7 @@ std::unique_ptr<syncer::Nigori> MakeTestNigoriKey() {
 
 crosapi::mojom::NigoriKeyPtr MakeTestMojoNigoriKey() {
   std::unique_ptr<syncer::Nigori> nigori_key = MakeTestNigoriKey();
-  return NigoriToMojoForTesting(*nigori_key);
+  return syncer::NigoriToMojo(*nigori_key);
 }
 
 crosapi::mojom::AccountKeyPtr MakeMojoAccountKey(

components/sync/BUILD.gn

@@ -16,6 +16,9 @@ group("sync") {
   if (!is_android) {
     public_deps += [ "//components/sync/trusted_vault" ]
   }
+  if (is_chromeos) {
+    public_deps += [ "//components/sync/chromeos" ]
+  }
 }
 
 group("test_support") {
@@ -219,6 +222,10 @@ source_set("unit_tests") {
     ]
   }
 
+  if (is_chromeos) {
+    sources += [ "chromeos/explicit_passphrase_mojo_utils_unittest.cc" ]
+  }
+
   configs += [ "//build/config:precompiled_headers" ]
 
   data = [

components/sync/chromeos/BUILD.gn

@@ -0,0 +1,12 @@
+# Copyright 2022 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+static_library("chromeos") {
+  sources = [
+    "explicit_passphrase_mojo_utils.cc",
+    "explicit_passphrase_mojo_utils.h",
+  ]
+  public_deps = [ "//chromeos/crosapi/mojom" ]
+  deps = [ "//components/sync/engine" ]
+}

components/sync/chromeos/DEPS

@@ -0,0 +1,4 @@
+include_rules = [
+  "+chromeos/crosapi/mojom",
+  "+components/sync/engine",
+]

components/sync/chromeos/explicit_passphrase_mojo_utils.cc

@@ -0,0 +1,38 @@
+// Copyright 2022 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/sync/chromeos/explicit_passphrase_mojo_utils.h"
+
+#include <string>
+#include <vector>
+
+#include "components/sync/engine/nigori/nigori.h"
+
+namespace syncer {
+
+crosapi::mojom::NigoriKeyPtr NigoriToMojo(const Nigori& nigori) {
+  std::string deprecated_user_key;
+  std::string encryption_key;
+  std::string mac_key;
+  nigori.ExportKeys(&deprecated_user_key, &encryption_key, &mac_key);
+
+  crosapi::mojom::NigoriKeyPtr mojo_result = crosapi::mojom::NigoriKey::New();
+  mojo_result->encryption_key =
+      std::vector<uint8_t>(encryption_key.begin(), encryption_key.end());
+  mojo_result->mac_key = std::vector<uint8_t>(mac_key.begin(), mac_key.end());
+  return mojo_result;
+}
+
+std::unique_ptr<Nigori> NigoriFromMojo(
+    const crosapi::mojom::NigoriKey& mojo_nigori_key) {
+  const std::string encryption_key(mojo_nigori_key.encryption_key.begin(),
+                                   mojo_nigori_key.encryption_key.end());
+  const std::string mac_key(mojo_nigori_key.mac_key.begin(),
+                            mojo_nigori_key.mac_key.end());
+  // |user_key| is deprecated, it's safe to pass empty string.
+  return Nigori::CreateByImport(
+      /*user_key=*/std::string(), encryption_key, mac_key);
+}
+
+}  // namespace syncer

components/sync/chromeos/explicit_passphrase_mojo_utils.h

@@ -0,0 +1,26 @@
+// Copyright 2022 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_SYNC_CHROMEOS_EXPLICIT_PASSPHRASE_MOJO_UTILS_H_
+#define COMPONENTS_SYNC_CHROMEOS_EXPLICIT_PASSPHRASE_MOJO_UTILS_H_
+
+#include <memory>
+
+#include "chromeos/crosapi/mojom/sync.mojom.h"
+
+namespace syncer {
+
+class Nigori;
+
+// Converts |nigori| into its mojo representation.
+crosapi::mojom::NigoriKeyPtr NigoriToMojo(const Nigori& nigori);
+
+// Creates Nigori from its mojo representation. Returns nullptr if
+// |mojo_nigori_key| doesn't represent a valid Nigori.
+std::unique_ptr<Nigori> NigoriFromMojo(
+    const crosapi::mojom::NigoriKey& mojo_nigori_key);
+
+}  // namespace syncer
+
+#endif  // COMPONENTS_SYNC_CHROMEOS_EXPLICIT_PASSPHRASE_MOJO_UTILS_H_

components/sync/chromeos/explicit_passphrase_mojo_utils_unittest.cc

@@ -0,0 +1,62 @@
+// Copyright 2022 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/sync/chromeos/explicit_passphrase_mojo_utils.h"
+
+#include <string>
+
+#include "chromeos/crosapi/mojom/sync.mojom.h"
+#include "components/sync/engine/nigori/key_derivation_params.h"
+#include "components/sync/engine/nigori/nigori.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace syncer {
+
+namespace {
+
+using testing::Eq;
+using testing::IsNull;
+using testing::NotNull;
+
+TEST(ExplicitPassphraseMojoUtilsTest, ShouldConvertNigoriToMojoAndBack) {
+  auto nigori1 = Nigori::CreateByDerivation(
+      KeyDerivationParams::CreateForPbkdf2(), "password");
+  ASSERT_THAT(nigori1, NotNull());
+
+  auto mojo_nigori_key = NigoriToMojo(*nigori1);
+  ASSERT_FALSE(mojo_nigori_key.is_null());
+
+  auto nigori2 = NigoriFromMojo(*mojo_nigori_key);
+  ASSERT_THAT(nigori2, NotNull());
+
+  std::string deprecated_user_key1;
+  std::string encryption_key1;
+  std::string mac_key1;
+  nigori1->ExportKeys(&deprecated_user_key1, &encryption_key1, &mac_key1);
+
+  std::string deprecated_user_key2;
+  std::string encryption_key2;
+  std::string mac_key2;
+  nigori2->ExportKeys(&deprecated_user_key2, &encryption_key2, &mac_key2);
+  // Don't check user key, because it's deprecated and safe to ignore.
+  EXPECT_THAT(encryption_key1, Eq(encryption_key2));
+  EXPECT_THAT(mac_key1, Eq(mac_key2));
+}
+
+TEST(ExplicitPassphraseMojoUtilsTest, ShouldFailMojoToNigoriIfMojoEmpty) {
+  auto empty_mojo_nigori_key = crosapi::mojom::NigoriKey::New();
+  EXPECT_THAT(NigoriFromMojo(*empty_mojo_nigori_key), IsNull());
+}
+
+TEST(ExplicitPassphraseMojoUtilsTest, ShouldFailMojoToNigoriIfMojoNotValid) {
+  auto invalid_mojo_nigori_key = crosapi::mojom::NigoriKey::New();
+  invalid_mojo_nigori_key->encryption_key = {1, 2, 3};
+  invalid_mojo_nigori_key->mac_key = {1, 2, 3};
+  EXPECT_THAT(NigoriFromMojo(*invalid_mojo_nigori_key), IsNull());
+}
+
+}  // namespace
+
+}  // namespace syncer