blob: b6d37f81c281ad202a94f021a14ad6c5f92ae95f [file] [log] [blame]
// Copyright 2015 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 "services/preferences/tracked/device_id.h"
#include <windows.h>
#include <sddl.h> // For ConvertSidToStringSidA.
#include <memory>
#include "base/check.h"
#include "base/stl_util.h"
MachineIdStatus GetDeterministicMachineSpecificId(std::string* machine_id) {
wchar_t computer_name[MAX_COMPUTERNAME_LENGTH + 1] = {};
DWORD computer_name_size = base::size(computer_name);
if (!::GetComputerNameW(computer_name, &computer_name_size))
return MachineIdStatus::FAILURE;
char sid_buffer[SECURITY_MAX_SID_SIZE];
SID* sid = reinterpret_cast<SID*>(sid_buffer);
DWORD domain_size = 128; // Will expand below if needed.
std::unique_ptr<wchar_t[]> domain_buffer(new wchar_t[domain_size]);
SID_NAME_USE sid_name_use;
// Although the fifth argument to |LookupAccountNameW()|,
// |ReferencedDomainName|, is annotated as |_Out_opt_|, if a null
// value is passed in, zero is returned and |GetLastError()| will
// return |ERROR_INSUFFICIENT_BUFFER| (assuming that nothing else went
// wrong). In order to ensure that the call to |LookupAccountNameW()|
// has succeeded, it is necessary to include the following logic and
// obtain the domain name.
if (!::LookupAccountNameW(nullptr, computer_name, sid, &sid_size,
domain_buffer.get(), &domain_size, &sid_name_use)) {
// If the initial size of |domain_buffer| was too small, the
// required size is now found in |domain_size|. Resize and try
// again.
return MachineIdStatus::FAILURE;
domain_buffer.reset(new wchar_t[domain_size]);
if (!::LookupAccountNameW(nullptr, computer_name, sid, &sid_size,
domain_buffer.get(), &domain_size,
&sid_name_use)) {
return MachineIdStatus::FAILURE;
// Ensure that the correct type of SID was obtained. The
// |LookupAccountNameW()| function seems to always return
// |SidTypeDomain| instead of |SidTypeComputer| when the computer name
// is passed in as its second argument and therefore both enum values
// will be considered acceptable. If the computer name and user name
// coincide, |LookupAccountNameW()| seems to always return the machine
// SID and set the returned enum to |SidTypeDomain|.
DCHECK(sid_name_use == SID_NAME_USE::SidTypeComputer ||
sid_name_use == SID_NAME_USE::SidTypeDomain);
char* sid_string = nullptr;
if (!::ConvertSidToStringSidA(sid, &sid_string))
return MachineIdStatus::FAILURE;
*machine_id = sid_string;
return MachineIdStatus::SUCCESS;