assistant: Sandbox libassistant service

This patch creates a new utility sandbox type of libassistant to sandbox
the Libassistant service.

Bug: b/155328340
Test: manual
Change-Id: Ib65ac7af93f5ee420909389aa03e5252f994782b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2799135
Commit-Queue: Tao Wu <wutao@chromium.org>
Reviewed-by: Sam McNally <sammc@chromium.org>
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#876474}

chrome/browser/BUILD.gn

@@ -16,6 +16,7 @@ import("//build/config/ui.gni")
 import("//chrome/browser/buildflags.gni")
 import("//chrome/browser/downgrade/buildflags.gni")
 import("//chrome/common/features.gni")
+import("//chromeos/assistant/assistant.gni")
 import("//components/captive_portal/core/features.gni")
 import("//components/feed/features.gni")
 import("//components/nacl/features.gni")
@@ -2431,6 +2432,10 @@ static_library("browser") {
         "//chromeos/components/telemetry_extension_ui/mojom",
       ]
     }
+
+    if (enable_libassistant_sandbox) {
+      deps += [ "//chromeos/services/libassistant/public/mojom" ]
+    }
   }
   if (is_linux || is_chromeos) {
     deps += [ "//chrome/browser/error_reporting" ]

chrome/browser/chromeos/service_sandbox_type.h

@@ -5,6 +5,7 @@
 #ifndef CHROME_BROWSER_CHROMEOS_SERVICE_SANDBOX_TYPE_H_
 #define CHROME_BROWSER_CHROMEOS_SERVICE_SANDBOX_TYPE_H_
 
+#include "chromeos/assistant/buildflags.h"
 #include "content/public/browser/service_process_host.h"
 #include "sandbox/policy/sandbox_type.h"
 
@@ -42,4 +43,20 @@ content::GetServiceSandboxType<chromeos::tts::mojom::TtsService>() {
   return sandbox::policy::SandboxType::kTts;
 }
 
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+namespace chromeos {
+namespace libassistant {
+namespace mojom {
+class LibassistantService;
+}  // namespace mojom
+}  // namespace libassistant
+}  // namespace chromeos
+
+template <>
+inline sandbox::policy::SandboxType content::GetServiceSandboxType<
+    chromeos::libassistant::mojom::LibassistantService>() {
+  return sandbox::policy::SandboxType::kLibassistant;
+}
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+
 #endif  // CHROME_BROWSER_CHROMEOS_SERVICE_SANDBOX_TYPE_H_

chrome/browser/ui/ash/assistant/assistant_client_impl.cc

@@ -32,6 +32,11 @@
 #include "content/public/common/content_switches.h"
 #include "services/network/public/cpp/shared_url_loader_factory.h"
 
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+#include "chrome/browser/chromeos/service_sandbox_type.h"
+#include "chromeos/services/libassistant/public/mojom/service.mojom.h"
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+
 AssistantClientImpl::AssistantClientImpl() {
   auto* session_manager = session_manager::SessionManager::Get();
   // AssistantClientImpl must be created before any user session is created.
@@ -162,6 +167,18 @@ void AssistantClientImpl::RequestNetworkConfig(
   ash::GetNetworkConfigService(std::move(receiver));
 }
 
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+void AssistantClientImpl::RequestLibassistantService(
+    mojo::PendingReceiver<chromeos::libassistant::mojom::LibassistantService>
+        receiver) {
+  content::ServiceProcessHost::Launch<
+      chromeos::libassistant::mojom::LibassistantService>(
+      std::move(receiver), content::ServiceProcessHost::Options()
+                               .WithDisplayName("Libassistant Service")
+                               .Pass());
+}
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+
 void AssistantClientImpl::OnExtendedAccountInfoUpdated(
     const AccountInfo& info) {
   if (initialized_)

chrome/browser/ui/ash/assistant/assistant_client_impl.h

@@ -13,6 +13,7 @@
 #include "base/macros.h"
 #include "base/scoped_observer.h"
 #include "chrome/browser/ui/ash/assistant/device_actions.h"
+#include "chromeos/assistant/buildflags.h"
 #include "chromeos/services/assistant/public/cpp/assistant_client.h"
 #include "chromeos/services/assistant/service.h"
 #include "components/session_manager/core/session_manager_observer.h"
@@ -78,6 +79,11 @@ class AssistantClientImpl : public ash::AssistantClient,
   void RequestNetworkConfig(
       mojo::PendingReceiver<chromeos::network_config::mojom::CrosNetworkConfig>
           receiver) override;
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+  void RequestLibassistantService(
+      mojo::PendingReceiver<chromeos::libassistant::mojom::LibassistantService>
+          receiver) override;
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 
  private:
   // signin::IdentityManager::Observer:

chrome/utility/BUILD.gn

@@ -176,6 +176,13 @@ static_library("utility") {
         "//chromeos/services/assistant/audio_decoder:lib",
         "//chromeos/services/assistant/public/mojom",
       ]
+
+      if (enable_libassistant_sandbox) {
+        deps += [
+          "//chromeos/services/libassistant",
+          "//chromeos/services/libassistant/public/mojom",
+        ]
+      }
     }
   }
 

chrome/utility/DEPS

@@ -27,6 +27,7 @@ include_rules = [
   "+chromeos/services/assistant",
   "+chromeos/services/ime/ime_service.h",
   "+chromeos/services/ime/public/mojom",
+  "+chromeos/services/libassistant/libassistant_service.h",
   "+chromeos/services/nearby",
   "+chromeos/services/tts",
   "+components/crash/core/common/crash_keys.h",

chrome/utility/services.cc

@@ -108,6 +108,10 @@
 
 #if BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
 #include "chromeos/services/assistant/audio_decoder/assistant_audio_decoder_factory.h"  // nogncheck
+
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+#include "chromeos/services/libassistant/libassistant_service.h"  // nogncheck
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 #endif  // BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
 
@@ -293,8 +297,17 @@ auto RunAssistantAudioDecoder(
   return std::make_unique<chromeos::assistant::AssistantAudioDecoderFactory>(
       std::move(receiver));
 }
-#endif
+
-#endif
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+auto RunLibassistantService(
+    mojo::PendingReceiver<chromeos::libassistant::mojom::LibassistantService>
+        receiver) {
+  return std::make_unique<chromeos::libassistant::LibassistantService>(
+      std::move(receiver));
+}
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+#endif  // BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
+#endif  // BUILDFLAG(IS_CHROMEOS_ASH)
 
 }  // namespace
 
@@ -374,8 +387,11 @@ void RegisterMainThreadServices(mojo::ServiceFactory& services) {
   services.Add(RunLocalSearchService);
 #if BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
   services.Add(RunAssistantAudioDecoder);
-#endif
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
-#endif
+  services.Add(RunLibassistantService);
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+#endif  // BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
+#endif  // BUILDFLAG(IS_CHROMEOS_ASH)
 }
 
 void RegisterIOThreadServices(mojo::ServiceFactory& services) {

chromeos/assistant/BUILD.gn

@@ -11,6 +11,7 @@ buildflag_header("buildflags") {
 
   flags = [
     "ENABLE_CROS_LIBASSISTANT=$enable_cros_libassistant",
+    "ENABLE_LIBASSISTANT_SANDBOX=$enable_cros_libassistant && $enable_libassistant_sandbox",
     "ENABLE_CROS_AMBIENT_MODE_BACKEND=$enable_cros_ambient_mode_backend",
   ]
 }

chromeos/assistant/assistant.gni

@@ -5,6 +5,9 @@ declare_args() {
   # Enable assistant implementation based on libassistant.
   enable_cros_libassistant = is_chromeos_ash && is_chrome_branded
 
+  # Enable sandboxing LibAssistant service.
+  enable_libassistant_sandbox = false
+
   # Enable a fake microphone, which can replay audio files as microphone input.
   # See chromeos/assistant/tools/send-audio.sh
   enable_fake_assistant_microphone = false

chromeos/services/assistant/BUILD.gn

@@ -95,6 +95,10 @@ source_set("libassistant_service_host") {
 
   if (enable_cros_libassistant) {
     deps += [ "//chromeos/services/libassistant" ]
+
+    if (enable_libassistant_sandbox) {
+      deps += [ "//chromeos/services/assistant/public/cpp" ]
+    }
   }
 }
 

chromeos/services/assistant/libassistant_service_host_impl.cc

@@ -11,7 +11,12 @@
 
 #if BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
 #include "chromeos/services/libassistant/libassistant_service.h"
-#endif
+
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+#include "chromeos/services/assistant/public/cpp/assistant_client.h"  // nogncheck
+#include "chromeos/services/libassistant/public/mojom/service.mojom-forward.h"  // nogncheck
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+#endif  // BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
 
 namespace chromeos {
 namespace assistant {
@@ -19,7 +24,9 @@ namespace assistant {
 #if BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
 
 LibassistantServiceHostImpl::LibassistantServiceHostImpl() {
+#if !BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
   DETACH_FROM_SEQUENCE(sequence_checker_);
+#endif
 }
 
 LibassistantServiceHostImpl::~LibassistantServiceHostImpl() = default;
@@ -27,16 +34,22 @@ LibassistantServiceHostImpl::~LibassistantServiceHostImpl() = default;
 void LibassistantServiceHostImpl::Launch(
     mojo::PendingReceiver<chromeos::libassistant::mojom::LibassistantService>
         receiver) {
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+  AssistantClient::Get()->RequestLibassistantService(std::move(receiver));
+#else
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   DCHECK(!libassistant_service_);
   libassistant_service_ =
       std::make_unique<chromeos::libassistant::LibassistantService>(
           std::move(receiver));
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 }
 
 void LibassistantServiceHostImpl::Stop() {
+#if !BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   libassistant_service_ = nullptr;
+#endif
 }
 
 #else

chromeos/services/assistant/libassistant_service_host_impl.h

@@ -37,7 +37,8 @@ class LibassistantServiceHostImpl : public LibassistantServiceHost {
   void Stop() override;
 
  private:
-#if BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
+#if BUILDFLAG(ENABLE_CROS_LIBASSISTANT) && \
+    !BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
   SEQUENCE_CHECKER(sequence_checker_);
   std::unique_ptr<chromeos::libassistant::LibassistantService>
       libassistant_service_ GUARDED_BY_CONTEXT(sequence_checker_);

chromeos/services/assistant/proxy/assistant_proxy.cc

@@ -55,6 +55,8 @@ void AssistantProxy::LaunchLibassistantServiceOnBackgroundThread(
 }
 
 void AssistantProxy::StopLibassistantService() {
+  libassistant_service_.reset();
+
   // |libassistant_service_| is launched on the background thread, so we have to
   // stop it there as well.
   background_task_runner()->PostTask(

chromeos/services/assistant/public/cpp/BUILD.gn

@@ -40,5 +40,8 @@ component("cpp") {
     "//ui/accessibility/mojom",
   ]
 
-  deps = [ "//components/prefs" ]
+  deps = [
+    "//chromeos/assistant:buildflags",
+    "//components/prefs",
+  ]
 }

chromeos/services/assistant/public/cpp/assistant_client.h

@@ -7,6 +7,7 @@
 
 #include "ash/public/mojom/assistant_volume_control.mojom.h"
 #include "base/component_export.h"
+#include "chromeos/assistant/buildflags.h"
 #include "chromeos/services/assistant/public/cpp/assistant_enums.h"
 #include "chromeos/services/assistant/public/mojom/assistant_audio_decoder.mojom.h"
 #include "chromeos/services/libassistant/public/cpp/assistant_notification.h"
@@ -18,6 +19,10 @@
 #include "services/media_session/public/mojom/audio_focus.mojom.h"
 #include "services/media_session/public/mojom/media_controller.mojom.h"
 
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+#include "chromeos/services/libassistant/public/mojom/service.mojom-forward.h"
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+
 namespace chromeos {
 namespace assistant {
 
@@ -74,6 +79,13 @@ class COMPONENT_EXPORT(ASSISTANT_SERVICE_PUBLIC) AssistantClient {
   virtual void RequestNetworkConfig(
       mojo::PendingReceiver<chromeos::network_config::mojom::CrosNetworkConfig>
           receiver) = 0;
+
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+  // Requests a connection to Libassistant service interface via the browser.
+  virtual void RequestLibassistantService(
+      mojo::PendingReceiver<chromeos::libassistant::mojom::LibassistantService>
+          receiver) = 0;
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 };
 
 }  // namespace assistant

chromeos/services/libassistant/BUILD.gn

@@ -7,6 +7,19 @@ import("//chromeos/assistant/assistant.gni")
 
 assert(enable_cros_libassistant)
 
+component("constants") {
+  output_name = "libassistant_constants"
+  defines = [ "IS_LIBASSISTANT_CONSTANTS_IMPL" ]
+  deps = [
+    "//base",
+    "//build:branding_buildflags",
+  ]
+  sources = [
+    "constants.cc",
+    "constants.h",
+  ]
+}
+
 component("libassistant") {
   sources = [
     "libassistant_service.cc",
@@ -29,6 +42,20 @@ component("libassistant") {
   output_name = "lib_libassistant_service"
 }
 
+source_set("sandbox_hook") {
+  sources = [
+    "libassistant_sandbox_hook.cc",
+    "libassistant_sandbox_hook.h",
+  ]
+
+  deps = [
+    ":constants",
+    "//base",
+    "//sandbox/linux:sandbox_services",
+    "//sandbox/policy",
+  ]
+}
+
 source_set("internal") {
   visibility = [ ":*" ]
 
@@ -82,7 +109,9 @@ source_set("internal") {
 
   deps = [
     ":audio",
+    ":constants",
     "//build/util:webkit_version",
+    "//chromeos/assistant:buildflags",
     "//chromeos/assistant/internal",
     "//chromeos/assistant/internal:buildflags",
     "//chromeos/assistant/internal:libassistant",

chromeos/services/libassistant/DEPS

@@ -6,6 +6,9 @@ include_rules = [
   "+media/audio",
   "+media/base",
   "+media/mojo/mojom",
+  "+sandbox/linux/syscall_broker/broker_command.h",
+  "+sandbox/linux/syscall_broker/broker_file_permission.h",
+  "+sandbox/policy/linux/sandbox_linux.h",
   "+services/audio/public",
   "+services/device/public/mojom",
   "+services/media_session/public/mojom",

chromeos/services/libassistant/constants.cc

@@ -0,0 +1,21 @@
+// Copyright 2021 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 "chromeos/services/libassistant/constants.h"
+
+#include "base/files/file_util.h"
+
+#define ASSISTANT_DIR_STRING "google-assistant-library"
+
+namespace chromeos {
+namespace libassistant {
+
+const base::FilePath::CharType kAssistantBaseDirPath[] =
+    FILE_PATH_LITERAL("/home/chronos/user/" ASSISTANT_DIR_STRING);
+
+const base::FilePath::CharType kAssistantTempBaseDirPath[] =
+    FILE_PATH_LITERAL("/tmp/" ASSISTANT_DIR_STRING);
+
+}  // namespace libassistant
+}  // namespace chromeos

chromeos/services/libassistant/constants.h

@@ -0,0 +1,25 @@
+// Copyright 2021 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 CHROMEOS_SERVICES_LIBASSISTANT_CONSTANTS_H_
+#define CHROMEOS_SERVICES_LIBASSISTANT_CONSTANTS_H_
+
+#include "base/component_export.h"
+#include "base/files/file_path.h"
+
+namespace chromeos {
+namespace libassistant {
+
+// A directory to save Assistant config files.
+COMPONENT_EXPORT(LIBASSISTANT_CONSTANTS)
+extern const base::FilePath::CharType kAssistantBaseDirPath[];
+
+// A directory used in gLinux simulation.
+COMPONENT_EXPORT(LIBASSISTANT_CONSTANTS)
+extern const base::FilePath::CharType kAssistantTempBaseDirPath[];
+
+}  // namespace libassistant
+}  // namespace chromeos
+
+#endif  // CHROMEOS_SERVICES_LIBASSISTANT_CONSTANTS_H_

chromeos/services/libassistant/file_provider_impl.cc

@@ -37,16 +37,16 @@ bool FileProviderImpl::WriteFile(const std::string& path,
 
   // Create a temp file.
   base::FilePath temp_file;
-  if (!base::CreateTemporaryFileInDir(full_path.DirName(), &temp_file)) {
+  auto fd = base::CreateAndOpenFdForTemporaryFileInDir(full_path.DirName(),
+                                                       &temp_file);
+  if (!fd.is_valid())
     return false;
-  }
 
   // Write to the tmp file.
-  const int size = data.size();
+  const bool success =
-  int written_size = base::WriteFile(temp_file, data.data(), size);
+      base::WriteFileDescriptor(fd.get(), data.data(), data.size());
-  if (written_size != size) {
+  if (!success)
     return false;
-  }
 
   // Replace the current file with the temp file.
   if (!base::ReplaceFile(temp_file, full_path, nullptr)) {

chromeos/services/libassistant/libassistant_sandbox_hook.cc

@@ -0,0 +1,73 @@
+// Copyright 2021 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 "chromeos/services/libassistant/libassistant_sandbox_hook.h"
+
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/system/sys_info.h"
+#include "chromeos/services/libassistant/constants.h"
+#include "sandbox/linux/syscall_broker/broker_command.h"
+#include "sandbox/linux/syscall_broker/broker_file_permission.h"
+#include "sandbox/policy/linux/sandbox_linux.h"
+
+using sandbox::syscall_broker::BrokerFilePermission;
+using sandbox::syscall_broker::MakeBrokerCommandSet;
+
+namespace chromeos {
+namespace libassistant {
+
+namespace {
+
+sandbox::syscall_broker::BrokerCommandSet GetLibassistantBrokerCommandSet() {
+  return MakeBrokerCommandSet({
+      sandbox::syscall_broker::COMMAND_ACCESS,
+      sandbox::syscall_broker::COMMAND_MKDIR,
+      sandbox::syscall_broker::COMMAND_OPEN,
+      sandbox::syscall_broker::COMMAND_RENAME,
+      sandbox::syscall_broker::COMMAND_STAT,
+      sandbox::syscall_broker::COMMAND_STAT64,
+  });
+}
+
+std::vector<BrokerFilePermission> GetLibassistantFilePermissions() {
+  base::FilePath assistant_path;
+  if (base::SysInfo::IsRunningOnChromeOS()) {
+    assistant_path =
+        base::FilePath(kAssistantBaseDirPath).AsEndingWithSeparator();
+  } else {
+    assistant_path =
+        base::FilePath(kAssistantTempBaseDirPath).AsEndingWithSeparator();
+  }
+  CHECK(base::CreateDirectory(assistant_path));
+
+  // Save Libassistant logs.
+  base::FilePath log_path =
+      assistant_path.Append(FILE_PATH_LITERAL("log")).AsEndingWithSeparator();
+  CHECK(base::CreateDirectory(log_path));
+
+  std::vector<BrokerFilePermission> permissions{
+      // Required by Libassistant to generate random string.
+      BrokerFilePermission::ReadOnly("/dev/urandom"),
+      BrokerFilePermission::ReadWriteCreateRecursive(assistant_path.value()),
+  };
+  return permissions;
+}
+
+}  // namespace
+
+bool LibassistantPreSandboxHook(
+    sandbox::policy::SandboxLinux::Options options) {
+  auto* instance = sandbox::policy::SandboxLinux::GetInstance();
+
+  instance->StartBrokerProcess(
+      GetLibassistantBrokerCommandSet(), GetLibassistantFilePermissions(),
+      sandbox::policy::SandboxLinux::PreSandboxHook(), options);
+
+  instance->EngageNamespaceSandboxIfPossible();
+  return true;
+}
+
+}  // namespace libassistant
+}  // namespace chromeos

chromeos/services/libassistant/libassistant_sandbox_hook.h

@@ -0,0 +1,18 @@
+// Copyright 2021 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 CHROMEOS_SERVICES_LIBASSISTANT_LIBASSISTANT_SANDBOX_HOOK_H_
+#define CHROMEOS_SERVICES_LIBASSISTANT_LIBASSISTANT_SANDBOX_HOOK_H_
+
+#include "sandbox/policy/linux/sandbox_linux.h"
+
+namespace chromeos {
+namespace libassistant {
+
+bool LibassistantPreSandboxHook(sandbox::policy::SandboxLinux::Options options);
+
+}  // namespace libassistant
+}  // namespace chromeos
+
+#endif  // CHROMEOS_SERVICES_LIBASSISTANT_LIBASSISTANT_SANDBOX_HOOK_H_

chromeos/services/libassistant/util.cc

@@ -12,10 +12,12 @@
 #include "base/system/sys_info.h"
 #include "base/values.h"
 #include "build/util/webkit_version.h"
+#include "chromeos/assistant/buildflags.h"
 #include "chromeos/assistant/internal/internal_constants.h"
 #include "chromeos/assistant/internal/util_headers.h"
 #include "chromeos/dbus/util/version_loader.h"
 #include "chromeos/services/assistant/public/cpp/features.h"
+#include "chromeos/services/libassistant/constants.h"
 
 using chromeos::assistant::shared::ClientInteraction;
 using chromeos::assistant::shared::ClientOpResult;
@@ -49,15 +51,6 @@ void CreateUserAgent(std::string* user_agent) {
     base::StringAppendF(user_agent, " ARC/%s", arc_version.c_str());
 }
 
-// Get the root path for assistant files.
-base::FilePath GetRootPath() {
-  base::FilePath home_dir;
-  CHECK(base::PathService::Get(base::DIR_HOME, &home_dir));
-  // Ensures DIR_HOME is overridden after primary user sign-in.
-  CHECK_NE(base::GetHomeDir(), home_dir);
-  return home_dir;
-}
-
 ProviderVerificationResult::VerificationStatus GetProviderVerificationStatus(
     AppStatus status) {
   switch (status) {
@@ -175,7 +168,10 @@ bool ShouldLogToFile() {
 }  // namespace
 
 base::FilePath GetBaseAssistantDir() {
-  return GetRootPath().Append(FILE_PATH_LITERAL("google-assistant-library"));
+  if (base::SysInfo::IsRunningOnChromeOS())
+    return base::FilePath(FILE_PATH_LITERAL(kAssistantBaseDirPath));
+
+  return base::FilePath(FILE_PATH_LITERAL(kAssistantTempBaseDirPath));
 }
 
 std::string CreateLibAssistantConfig(
@@ -221,9 +217,12 @@ std::string CreateLibAssistantConfig(
     if (ShouldPutLogsInHomeDirectory()) {
       base::FilePath log_path =
           GetBaseAssistantDir().Append(FILE_PATH_LITERAL("log"));
+#if !BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
       CHECK(base::CreateDirectory(log_path));
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
       log_dir = log_path.value();
     }
+
     logging.SetKey("directory", Value(log_dir));
     // Maximum disk space consumed by all log files. There are 5 rotating log
     // files on disk.

content/browser/utility_sandbox_delegate.cc

@@ -15,6 +15,10 @@
 #include "content/common/zygote/zygote_handle_impl_linux.h"
 #endif
 
+#if BUILDFLAG(IS_CHROMEOS_ASH)
+#include "chromeos/assistant/buildflags.h"
+#endif
+
 namespace content {
 
 UtilitySandboxedProcessLauncherDelegate::
@@ -50,6 +54,9 @@ UtilitySandboxedProcessLauncherDelegate::
 #if BUILDFLAG(IS_CHROMEOS_ASH)
       sandbox_type_ == sandbox::policy::SandboxType::kIme ||
       sandbox_type_ == sandbox::policy::SandboxType::kTts ||
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+      sandbox_type_ == sandbox::policy::SandboxType::kLibassistant ||
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
       sandbox_type_ == sandbox::policy::SandboxType::kAudio ||
 #if !defined(OS_MAC)
@@ -87,6 +94,9 @@ ZygoteHandle UtilitySandboxedProcessLauncherDelegate::GetZygote() {
 #if BUILDFLAG(IS_CHROMEOS_ASH)
       sandbox_type_ == sandbox::policy::SandboxType::kIme ||
       sandbox_type_ == sandbox::policy::SandboxType::kTts ||
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+      sandbox_type_ == sandbox::policy::SandboxType::kLibassistant ||
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
       sandbox_type_ == sandbox::policy::SandboxType::kAudio ||
       sandbox_type_ == sandbox::policy::SandboxType::kPrintBackend ||

content/utility/BUILD.gn

@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import("//build/config/chromeos/ui_mode.gni")
+import("//chromeos/assistant/assistant.gni")
 import("//device/vr/buildflags/buildflags.gni")
 import("//media/media_options.gni")
 
@@ -77,6 +78,7 @@ source_set("utility") {
 
   if (is_chromeos_ash) {
     deps += [
+      "//chromeos/assistant:buildflags",
       "//chromeos/services/ime:sandbox_hook",
       "//chromeos/services/tts:sandbox_hook",
     ]
@@ -89,6 +91,10 @@ source_set("utility") {
     ]
   }
 
+  if (enable_libassistant_sandbox) {
+    deps += [ "//chromeos/services/libassistant:sandbox_hook" ]
+  }
+
   # PAC execution is done in process on Android.
   if (!is_android) {
     deps += [ "//services/proxy_resolver:lib" ]

content/utility/DEPS

@@ -3,7 +3,9 @@ include_rules = [
   "+content/child",
   "+content/public/utility",
   "+content/services",
+  "+chromeos/assistant/buildflags.h",
   "+chromeos/services/ime",
+  "+chromeos/services/libassistant",
   "+chromeos/services/tts",
   "+device/vr/buildflags",
   "+device/vr/public",

content/utility/utility_main.cc

@@ -37,8 +37,13 @@
 #endif
 
 #if BUILDFLAG(IS_CHROMEOS_ASH)
+#include "chromeos/assistant/buildflags.h"
 #include "chromeos/services/ime/ime_sandbox_hook.h"
 #include "chromeos/services/tts/tts_sandbox_hook.h"
+
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+#include "chromeos/services/libassistant/libassistant_sandbox_hook.h"  // nogncheck
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 #endif
 
 #if defined(OS_MAC)
@@ -109,6 +114,9 @@ int UtilityMain(const MainFunctionParams& parameters) {
 #if BUILDFLAG(IS_CHROMEOS_ASH)
       sandbox_type == sandbox::policy::SandboxType::kIme ||
       sandbox_type == sandbox::policy::SandboxType::kTts ||
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+      sandbox_type == sandbox::policy::SandboxType::kLibassistant ||
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
       sandbox_type == sandbox::policy::SandboxType::kPrintBackend ||
       sandbox_type == sandbox::policy::SandboxType::kAudio ||
@@ -128,6 +136,12 @@ int UtilityMain(const MainFunctionParams& parameters) {
       pre_sandbox_hook = base::BindOnce(&chromeos::ime::ImePreSandboxHook);
     else if (sandbox_type == sandbox::policy::SandboxType::kTts)
       pre_sandbox_hook = base::BindOnce(&chromeos::tts::TtsPreSandboxHook);
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+    else if (sandbox_type == sandbox::policy::SandboxType::kLibassistant) {
+      pre_sandbox_hook =
+          base::BindOnce(&chromeos::libassistant::LibassistantPreSandboxHook);
+    }
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
 
     sandbox::policy::Sandbox::Initialize(

sandbox/policy/BUILD.gn

@@ -6,6 +6,7 @@ import("//build/buildflag_header.gni")
 import("//build/config/chromecast_build.gni")
 import("//build/config/chromeos/ui_mode.gni")
 import("//build/config/sanitizers/sanitizers.gni")
+import("//chromeos/assistant/assistant.gni")
 import("//testing/test.gni")
 
 component("policy") {
@@ -87,6 +88,14 @@ component("policy") {
       "linux/bpf_tts_policy_linux.cc",
       "linux/bpf_tts_policy_linux.h",
     ]
+    deps += [ "//chromeos/assistant:buildflags" ]
+
+    if (enable_libassistant_sandbox) {
+      sources += [
+        "linux/bpf_libassistant_policy_linux.cc",
+        "linux/bpf_libassistant_policy_linux.h",
+      ]
+    }
   }
   if (is_mac) {
     sources += [

sandbox/policy/DEPS

@@ -1,4 +1,5 @@
 include_rules = [
+  "+chromeos/assistant/buildflags.h",
   "+sandbox/constants.h",
   "+sandbox",
 ]

sandbox/policy/linux/bpf_libassistant_policy_linux.cc

@@ -0,0 +1,40 @@
+// Copyright 2021 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 "sandbox/policy/linux/bpf_libassistant_policy_linux.h"
+
+#include <sys/socket.h>
+
+#include "sandbox/linux/bpf_dsl/bpf_dsl.h"
+#include "sandbox/linux/seccomp-bpf-helpers/syscall_parameters_restrictions.h"
+#include "sandbox/linux/syscall_broker/broker_process.h"
+#include "sandbox/linux/system_headers/linux_syscalls.h"
+#include "sandbox/policy/linux/sandbox_linux.h"
+
+using sandbox::bpf_dsl::Allow;
+using sandbox::bpf_dsl::ResultExpr;
+using sandbox::bpf_dsl::Trap;
+using sandbox::syscall_broker::BrokerProcess;
+
+namespace sandbox {
+namespace policy {
+
+LibassistantProcessPolicy::LibassistantProcessPolicy() = default;
+LibassistantProcessPolicy::~LibassistantProcessPolicy() = default;
+
+ResultExpr LibassistantProcessPolicy::EvaluateSyscall(int sysno) const {
+#if defined(__NR_sched_setscheduler)
+  if (sysno == __NR_sched_setscheduler)
+    return Allow();
+#endif
+
+  auto* sandbox_linux = SandboxLinux::GetInstance();
+  if (sandbox_linux->ShouldBrokerHandleSyscall(sysno))
+    return sandbox_linux->HandleViaBroker();
+
+  return BPFBasePolicy::EvaluateSyscall(sysno);
+}
+
+}  // namespace policy
+}  // namespace sandbox

sandbox/policy/linux/bpf_libassistant_policy_linux.h

@@ -0,0 +1,28 @@
+// Copyright 2021 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 SANDBOX_POLICY_LINUX_BPF_LIBASSISTANT_POLICY_LINUX_H_
+#define SANDBOX_POLICY_LINUX_BPF_LIBASSISTANT_POLICY_LINUX_H_
+
+#include "sandbox/policy/linux/bpf_base_policy_linux.h"
+
+namespace sandbox {
+namespace policy {
+
+// This policy can be used by Libassistant utility processes.
+class LibassistantProcessPolicy : public BPFBasePolicy {
+ public:
+  LibassistantProcessPolicy();
+  LibassistantProcessPolicy(const LibassistantProcessPolicy&) = delete;
+  LibassistantProcessPolicy& operator=(const LibassistantProcessPolicy&) =
+      delete;
+  ~LibassistantProcessPolicy() override;
+
+  bpf_dsl::ResultExpr EvaluateSyscall(int sysno) const override;
+};
+
+}  // namespace policy
+}  // namespace sandbox
+
+#endif  // SANDBOX_POLICY_LINUX_BPF_LIBASSISTANT_POLICY_LINUX_H_

sandbox/policy/linux/sandbox_seccomp_bpf_linux.cc

@@ -58,6 +58,11 @@
 #include "sandbox/policy/features.h"
 #include "sandbox/policy/linux/bpf_ime_policy_linux.h"
 #include "sandbox/policy/linux/bpf_tts_policy_linux.h"
+
+#include "chromeos/assistant/buildflags.h"
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+#include "sandbox/policy/linux/bpf_libassistant_policy_linux.h"
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
 
 using sandbox::bpf_dsl::Allow;
@@ -191,6 +196,10 @@ std::unique_ptr<BPFBasePolicy> SandboxSeccompBPF::PolicyForSandboxType(
       return std::make_unique<ImeProcessPolicy>();
     case SandboxType::kTts:
       return std::make_unique<TtsProcessPolicy>();
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+    case SandboxType::kLibassistant:
+      return std::make_unique<LibassistantProcessPolicy>();
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
     case SandboxType::kZygoteIntermediateSandbox:
     case SandboxType::kNoSandbox:
@@ -235,6 +244,9 @@ void SandboxSeccompBPF::RunSandboxSanityChecks(
 #if BUILDFLAG(IS_CHROMEOS_ASH)
     case SandboxType::kIme:
     case SandboxType::kTts:
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+    case SandboxType::kLibassistant:
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
     case SandboxType::kAudio:
     case SandboxType::kSharingService:

sandbox/policy/sandbox_type.cc

@@ -55,6 +55,9 @@ bool IsUnsandboxedSandboxType(SandboxType sandbox_type) {
 #if BUILDFLAG(IS_CHROMEOS_ASH)
     case SandboxType::kIme:
     case SandboxType::kTts:
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+    case SandboxType::kLibassistant:
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 #endif
 #if !defined(OS_MAC)
     case SandboxType::kSharingService:
@@ -121,6 +124,9 @@ void SetCommandLineFlagsForSandboxType(base::CommandLine* command_line,
 #if BUILDFLAG(IS_CHROMEOS_ASH)
     case SandboxType::kIme:
     case SandboxType::kTts:
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+    case SandboxType::kLibassistant:
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
 #if !defined(OS_MAC)
     case SandboxType::kSharingService:
@@ -250,6 +256,10 @@ std::string StringFromUtilitySandboxType(SandboxType sandbox_type) {
       return switches::kImeSandbox;
     case SandboxType::kTts:
       return switches::kTtsSandbox;
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+    case SandboxType::kLibassistant:
+      return switches::kLibassistantSandbox;
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
       // The following are not utility processes so should not occur.
     case SandboxType::kRenderer:
@@ -311,6 +321,10 @@ SandboxType UtilitySandboxTypeFromString(const std::string& sandbox_string) {
     return SandboxType::kIme;
   if (sandbox_string == switches::kTtsSandbox)
     return SandboxType::kTts;
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+  if (sandbox_string == switches::kLibassistantSandbox)
+    return SandboxType::kLibassistant;
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
   return SandboxType::kUtility;
 }

sandbox/policy/sandbox_type.h

@@ -12,6 +12,10 @@
 #include "build/chromeos_buildflags.h"
 #include "sandbox/policy/export.h"
 
+#if BUILDFLAG(IS_CHROMEOS_ASH)
+#include "chromeos/assistant/buildflags.h"
+#endif  // BUILDFLAG(IS_CHROMEOS_ASH)
+
 namespace sandbox {
 namespace policy {
 
@@ -77,6 +81,11 @@ enum class SandboxType {
   kIme,
   // Text-to-speech.
   kTts,
+
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+  kLibassistant,
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
 
 #if defined(OS_LINUX) || defined(OS_CHROMEOS)

sandbox/policy/switches.cc

@@ -46,6 +46,9 @@ const char kMediaFoundationCdmSandbox[] = "mf_cdm";
 #if BUILDFLAG(IS_CHROMEOS_ASH)
 const char kImeSandbox[] = "ime";
 const char kTtsSandbox[] = "tts";
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+const char kLibassistantSandbox[] = "libassistant";
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
 
 // Flags owned by the service manager sandbox.

sandbox/policy/switches.h

@@ -9,6 +9,10 @@
 #include "build/chromeos_buildflags.h"
 #include "sandbox/policy/export.h"
 
+#if BUILDFLAG(IS_CHROMEOS_ASH)
+#include "chromeos/assistant/buildflags.h"
+#endif  // BUILDFLAG(IS_CHROMEOS_ASH)
+
 namespace sandbox {
 namespace policy {
 namespace switches {
@@ -43,6 +47,9 @@ SANDBOX_POLICY_EXPORT extern const char kMediaFoundationCdmSandbox[];
 #if BUILDFLAG(IS_CHROMEOS_ASH)
 SANDBOX_POLICY_EXPORT extern const char kImeSandbox[];
 SANDBOX_POLICY_EXPORT extern const char kTtsSandbox[];
+#if BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
+SANDBOX_POLICY_EXPORT extern const char kLibassistantSandbox[];
+#endif  // BUILDFLAG(ENABLE_LIBASSISTANT_SANDBOX)
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
 
 // Flags owned by the service manager sandbox.