1// Copyright (c) 2013 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 "chrome/browser/chromeos/login/hwid_checker.h"
6
7#include <cstdio>
8
9#include "base/command_line.h"
10#include "base/logging.h"
11#include "base/strings/string_util.h"
12#include "base/sys_info.h"
13#include "chrome/common/chrome_switches.h"
14#include "chromeos/chromeos_switches.h"
15#include "chromeos/system/statistics_provider.h"
16#include "third_party/re2/re2/re2.h"
17#include "third_party/zlib/zlib.h"
18
19namespace {
20
21unsigned CalculateCRC32(const std::string& data) {
22  return static_cast<unsigned>(crc32(
23      0,
24      reinterpret_cast<const Bytef*>(data.c_str()),
25      data.length()));
26}
27
28std::string CalculateHWIDv2Checksum(const std::string& data) {
29  unsigned crc32 = CalculateCRC32(data);
30  // We take four least significant decimal digits of CRC-32.
31  char checksum[5];
32  int snprintf_result =
33      snprintf(checksum, 5, "%04u", crc32 % 10000);
34  LOG_ASSERT(snprintf_result == 4);
35  return checksum;
36}
37
38bool IsCorrectHWIDv2(const std::string& hwid) {
39  std::string body;
40  std::string checksum;
41  if (!RE2::FullMatch(hwid, "([\\s\\S]*) (\\d{4})", &body, &checksum))
42    return false;
43  return CalculateHWIDv2Checksum(body) == checksum;
44}
45
46bool IsExceptionalHWID(const std::string& hwid) {
47  return RE2::PartialMatch(hwid, "^(SPRING [A-D])|(FALCO A)");
48}
49
50std::string CalculateExceptionalHWIDChecksum(const std::string& data) {
51  static const char base32_alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
52  unsigned crc32 = CalculateCRC32(data);
53  // We take 10 least significant bits of CRC-32 and encode them in 2 characters
54  // using Base32 alphabet.
55  std::string checksum;
56  checksum += base32_alphabet[(crc32 >> 5) & 0x1f];
57  checksum += base32_alphabet[crc32 & 0x1f];
58  return checksum;
59}
60
61bool IsCorrectExceptionalHWID(const std::string& hwid) {
62  if (!IsExceptionalHWID(hwid))
63    return false;
64  std::string bom;
65  if (!RE2::FullMatch(hwid, "[A-Z0-9]+ ((?:[A-Z2-7]{4}-)*[A-Z2-7]{1,4})", &bom))
66    return false;
67  if (bom.length() < 2)
68    return false;
69  std::string hwid_without_dashes;
70  base::RemoveChars(hwid, "-", &hwid_without_dashes);
71  LOG_ASSERT(hwid_without_dashes.length() >= 2);
72  std::string not_checksum =
73      hwid_without_dashes.substr(0, hwid_without_dashes.length() - 2);
74  std::string checksum =
75      hwid_without_dashes.substr(hwid_without_dashes.length() - 2);
76  return CalculateExceptionalHWIDChecksum(not_checksum) == checksum;
77}
78
79std::string CalculateHWIDv3Checksum(const std::string& data) {
80  static const char base8_alphabet[] = "23456789";
81  static const char base32_alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
82  unsigned crc32 = CalculateCRC32(data);
83  // We take 8 least significant bits of CRC-32 and encode them in 2 characters.
84  std::string checksum;
85  checksum += base8_alphabet[(crc32 >> 5) & 0x7];
86  checksum += base32_alphabet[crc32 & 0x1f];
87  return checksum;
88}
89
90bool IsCorrectHWIDv3(const std::string& hwid) {
91  if (IsExceptionalHWID(hwid))
92    return false;
93  std::string regex =
94      "([A-Z0-9]+ (?:[A-Z2-7][2-9][A-Z2-7]-)*[A-Z2-7])([2-9][A-Z2-7])";
95  std::string not_checksum, checksum;
96  if (!RE2::FullMatch(hwid, regex, &not_checksum, &checksum))
97    return false;
98  base::RemoveChars(not_checksum, "-", &not_checksum);
99  return CalculateHWIDv3Checksum(not_checksum) == checksum;
100}
101
102} // anonymous namespace
103
104namespace chromeos {
105
106bool IsHWIDCorrect(const std::string& hwid) {
107  return IsCorrectHWIDv2(hwid) || IsCorrectExceptionalHWID(hwid) ||
108      IsCorrectHWIDv3(hwid);
109}
110
111bool IsMachineHWIDCorrect() {
112#if !defined(GOOGLE_CHROME_BUILD)
113  return true;
114#endif
115  CommandLine* cmd_line = CommandLine::ForCurrentProcess();
116  if (cmd_line->HasSwitch(::switches::kTestType))
117    return true;
118  if (!base::SysInfo::IsRunningOnChromeOS())
119    return true;
120  std::string hwid;
121  chromeos::system::StatisticsProvider* stats =
122      chromeos::system::StatisticsProvider::GetInstance();
123  if (!stats->GetMachineStatistic(chromeos::system::kHardwareClassKey, &hwid)) {
124    LOG(ERROR) << "Couldn't get machine statistic 'hardware_class'.";
125    return false;
126  }
127  if (!chromeos::IsHWIDCorrect(hwid)) {
128    LOG(ERROR) << "Machine has malformed HWID '" << hwid << "'.";
129    return false;
130  }
131  return true;
132}
133
134} // namespace chromeos
135