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// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/browser/child_process_launcher_helper.h"
#include "base/base_switches.h"
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/logging.h"
#include "base/process/process.h"
#include "base/strings/string_number_conversions.h"
#include "base/win/scoped_handle.h"
#include "base/win/win_util.h"
#include "base/win/windows_version.h"
#include "build/build_config.h"
#include "content/browser/child_process_launcher.h"
#include "content/public/browser/child_process_launcher_utils.h"
#include "content/public/common/content_features.h"
#include "content/public/common/content_switches.h"
#include "content/public/common/result_codes.h"
#include "content/public/common/sandbox_init_win.h"
#include "content/public/common/sandboxed_process_launcher_delegate.h"
#include "mojo/public/cpp/platform/named_platform_channel.h"
#include "mojo/public/cpp/platform/platform_channel.h"
namespace {
// Helper to avoid marking the log file as non-executable every time we launch a
// process.
bool ShouldMarkLogfileAsNonExecute() {
static bool first_time = true;
if (!first_time) {
return false;
}
first_time = false;
return true;
}
} // namespace
namespace content {
namespace internal {
void ChildProcessLauncherHelper::BeforeLaunchOnClientThread() {
DCHECK(client_task_runner_->RunsTasksInCurrentSequence());
}
std::optional<mojo::NamedPlatformChannel>
ChildProcessLauncherHelper::CreateNamedPlatformChannelOnLauncherThread() {
DCHECK(CurrentlyOnProcessLauncherTaskRunner());
if (!delegate_->ShouldLaunchElevated())
return std::nullopt;
mojo::NamedPlatformChannel::Options options;
mojo::NamedPlatformChannel named_channel(options);
named_channel.PassServerNameOnCommandLine(command_line());
return named_channel;
}
std::unique_ptr<FileMappedForLaunch>
ChildProcessLauncherHelper::GetFilesToMap() {
// Windows uses LaunchOptions to pass filehandles to children.
return nullptr;
}
void ChildProcessLauncherHelper::PassLoggingSwitches(
base::LaunchOptions* launch_options,
base::CommandLine* cmd_line) {
const base::CommandLine& browser_command_line =
*base::CommandLine::ForCurrentProcess();
// Sandboxed processes on Windows cannot open files, and can't always figure
// out default paths, so we directly pass a handle if logging is enabled.
if (logging::IsLoggingToFileEnabled()) {
// Make sure we're in charge of these flags.
CHECK(!cmd_line->HasSwitch(switches::kEnableLogging));
CHECK(!cmd_line->HasSwitch(switches::kLogFile));
// Make best efforts attempt to mark the logfile as no-execute the first
// time a process is started.
if (ShouldMarkLogfileAsNonExecute()) {
// Failure here means we pass in a writeable handle to a file that could
// be marked executable and chained into a sandbox escape - but failure
// should be rare and providing a logfile is already optional.
std::ignore = base::PreventExecuteMappingUnchecked(
base::FilePath(logging::GetLogFileFullPath()),
base::PreventExecuteMappingClasses::GetPassKey());
}
log_handle_.Set(logging::DuplicateLogFileHandle());
if (log_handle_.is_valid()) {
// Override `--enable-logging --log-file=` switches so the child can log.
cmd_line->AppendSwitchASCII(switches::kEnableLogging, "handle");
auto handle_str =
base::NumberToString(base::win::HandleToUint32(log_handle_.get()));
cmd_line->AppendSwitchASCII(switches::kLogFile, handle_str);
launch_options->handles_to_inherit.push_back(log_handle_.get());
}
}
#if !defined(OFFICIAL_BUILD)
// Official builds do not send std handles to children so there is no point
// in passing --enable-logging by itself. Debug builds might need to know if
// stderr is being forced or not.
else if (browser_command_line.HasSwitch(switches::kEnableLogging)) {
std::string logging_destination =
browser_command_line.GetSwitchValueASCII(switches::kEnableLogging);
cmd_line->AppendSwitchASCII(switches::kEnableLogging, logging_destination);
}
#endif
// Forward other switches like other platforms.
constexpr const char* kForwardSwitches[] = {
switches::kDisableLogging,
switches::kLoggingLevel,
switches::kV,
switches::kVModule,
};
cmd_line->CopySwitchesFrom(browser_command_line, kForwardSwitches);
}
bool ChildProcessLauncherHelper::IsUsingLaunchOptions() {
return true;
}
bool ChildProcessLauncherHelper::BeforeLaunchOnLauncherThread(
FileMappedForLaunch& files_to_register,
base::LaunchOptions* options) {
DCHECK(CurrentlyOnProcessLauncherTaskRunner());
DCHECK_EQ(options->elevated, delegate_->ShouldLaunchElevated());
if (!options->elevated) {
mojo_channel_->PrepareToPassRemoteEndpoint(&options->handles_to_inherit,
command_line());
}
return true;
}
ChildProcessLauncherHelper::Process
ChildProcessLauncherHelper::LaunchProcessOnLauncherThread(
const base::LaunchOptions* options,
std::unique_ptr<FileMappedForLaunch> files_to_register,
bool* is_synchronous_launch,
int* launch_result) {
DCHECK(CurrentlyOnProcessLauncherTaskRunner());
*is_synchronous_launch = true;
if (delegate_->ShouldLaunchElevated()) {
DCHECK(options->elevated);
// When establishing a Mojo connection, the pipe path has already been added
// to the command line.
base::LaunchOptions win_options;
win_options.start_hidden = true;
win_options.elevated = true;
ChildProcessLauncherHelper::Process process;
process.process = base::LaunchProcess(*command_line(), win_options);
*launch_result = process.process.IsValid() ? LAUNCH_RESULT_SUCCESS
: LAUNCH_RESULT_FAILURE;
return process;
}
*is_synchronous_launch = false;
*launch_result = StartSandboxedProcess(
delegate_.get(), *command_line(), options->handles_to_inherit,
base::BindOnce(&ChildProcessLauncherHelper::
FinishStartSandboxedProcessOnLauncherThread,
this));
return ChildProcessLauncherHelper::Process();
}
void ChildProcessLauncherHelper::FinishStartSandboxedProcessOnLauncherThread(
base::Process process,
DWORD last_error,
int launch_result) {
DCHECK(CurrentlyOnProcessLauncherTaskRunner());
ChildProcessLauncherHelper::Process process_wrapper;
process_wrapper.process = std::move(process);
PostLaunchOnLauncherThread(std::move(process_wrapper), last_error,
launch_result);
}
void ChildProcessLauncherHelper::AfterLaunchOnLauncherThread(
const ChildProcessLauncherHelper::Process& process,
const base::LaunchOptions* options) {
DCHECK(CurrentlyOnProcessLauncherTaskRunner());
}
ChildProcessTerminationInfo ChildProcessLauncherHelper::GetTerminationInfo(
const ChildProcessLauncherHelper::Process& process,
bool known_dead) {
ChildProcessTerminationInfo info;
info.status =
base::GetTerminationStatus(process.process.Handle(), &info.exit_code);
return info;
}
// static
bool ChildProcessLauncherHelper::TerminateProcess(const base::Process& process,
int exit_code) {
return process.Terminate(exit_code, false);
}
void ChildProcessLauncherHelper::ForceNormalProcessTerminationSync(
ChildProcessLauncherHelper::Process process) {
DCHECK(CurrentlyOnProcessLauncherTaskRunner());
// Client has gone away, so just kill the process. Using exit code 0 means
// that UMA won't treat this as a crash.
process.process.Terminate(RESULT_CODE_NORMAL_EXIT, false);
}
void ChildProcessLauncherHelper::SetProcessPriorityOnLauncherThread(
base::Process process,
base::Process::Priority priority) {
DCHECK(CurrentlyOnProcessLauncherTaskRunner());
if (process.CanSetPriority()) {
process.SetPriority(priority);
}
}
} // namespace internal
} // namespace content
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