rlz/win/lib/machine_id_win.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include <windows.h>
   6 #include <Sddl.h>  // For ConvertSidToStringSidW.
   7 #include <string>
   8
   9 #include "base/memory/scoped_ptr.h"
  10 #include "base/strings/string16.h"
  11 #include "rlz/lib/assert.h"
  12
  13 namespace rlz_lib {
  14
  15 namespace {
  16
  17 bool GetSystemVolumeSerialNumber(int* number) {
  18   if (!number)
  19     return false;
  20
  21   *number = 0;
  22
  23   // Find the system root path (e.g: C:\).
  24   wchar_t system_path[MAX_PATH + 1];
  25   if (!GetSystemDirectoryW(system_path, MAX_PATH))
  26     return false;
  27
  28   wchar_t* first_slash = wcspbrk(system_path, L"\\/");
  29   if (first_slash != NULL)
  30     *(first_slash + 1) = 0;
  31
  32   DWORD number_local = 0;
  33   if (!GetVolumeInformationW(system_path, NULL, 0, &number_local, NULL, NULL,
  34                              NULL, 0))
  35     return false;
  36
  37   *number = number_local;
  38   return true;
  39 }
  40
  41 bool GetComputerSid(const wchar_t* account_name, SID* sid, DWORD sid_size) {
  42   static const DWORD kStartDomainLength = 128;  // reasonable to start with
  43
  44   scoped_ptr<wchar_t[]> domain_buffer(new wchar_t[kStartDomainLength]);
  45   DWORD domain_size = kStartDomainLength;
  46   DWORD sid_dword_size = sid_size;
  47   SID_NAME_USE sid_name_use;
  48
  49   BOOL success = ::LookupAccountNameW(NULL, account_name, sid,
  50                                       &sid_dword_size, domain_buffer.get(),
  51                                       &domain_size, &sid_name_use);
  52   if (!success && ::GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
  53     // We could have gotten the insufficient buffer error because
  54     // one or both of sid and szDomain was too small. Check for that
  55     // here.
  56     if (sid_dword_size > sid_size)
  57       return false;
  58
  59     if (domain_size > kStartDomainLength)
  60       domain_buffer.reset(new wchar_t[domain_size]);
  61
  62     success = ::LookupAccountNameW(NULL, account_name, sid, &sid_dword_size,
  63                                    domain_buffer.get(), &domain_size,
  64                                    &sid_name_use);
  65   }
  66
  67   return success != FALSE;
  68 }
  69
  70 std::wstring ConvertSidToString(SID* sid) {
  71   std::wstring sid_string;
  72 #if _WIN32_WINNT >= 0x500
  73   wchar_t* sid_buffer = NULL;
  74   if (ConvertSidToStringSidW(sid, &sid_buffer)) {
  75     sid_string = sid_buffer;
  76     LocalFree(sid_buffer);
  77   }
  78 #else
  79   SID_IDENTIFIER_AUTHORITY* sia = ::GetSidIdentifierAuthority(sid);
  80
  81   if(sia->Value[0] || sia->Value[1]) {
  82     base::SStringPrintf(
  83         &sid_string, L"S-%d-0x%02hx%02hx%02hx%02hx%02hx%02hx",
  84         SID_REVISION, (USHORT)sia->Value[0], (USHORT)sia->Value[1],
  85         (USHORT)sia->Value[2], (USHORT)sia->Value[3], (USHORT)sia->Value[4],
  86         (USHORT)sia->Value[5]);
  87   } else {
  88     ULONG authority = 0;
  89     for (int i = 2; i < 6; ++i) {
  90       authority <<= 8;
  91       authority |= sia->Value[i];
  92     }
  93     base::SStringPrintf(&sid_string, L"S-%d-%lu", SID_REVISION, authority);
  94   }
  95
  96   int sub_auth_count = *::GetSidSubAuthorityCount(sid);
  97   for(int i = 0; i < sub_auth_count; ++i)
  98     base::StringAppendF(&sid_string, L"-%lu", *::GetSidSubAuthority(sid, i));
  99 #endif
 100
 101   return sid_string;
 102 }
 103
 104 }  // namespace
 105
 106 bool GetRawMachineId(base::string16* sid_string, int* volume_id) {
 107   // Calculate the Windows SID.
 108
 109   wchar_t computer_name[MAX_COMPUTERNAME_LENGTH + 1] = {0};
 110   DWORD size = arraysize(computer_name);
 111
 112   if (GetComputerNameW(computer_name, &size)) {
 113     char sid_buffer[SECURITY_MAX_SID_SIZE];
 114     SID* sid = reinterpret_cast<SID*>(sid_buffer);
 115     if (GetComputerSid(computer_name, sid, SECURITY_MAX_SID_SIZE)) {
 116       *sid_string = ConvertSidToString(sid);
 117     }
 118   }
 119
 120   // Get the system drive volume serial number.
 121   *volume_id = 0;
 122   if (!GetSystemVolumeSerialNumber(volume_id)) {
 123     ASSERT_STRING("GetMachineId: Failed to retrieve volume serial number");
 124     *volume_id = 0;
 125   }
 126
 127   return true;
 128 }
 129
 130 }  // namespace rlz_lib