blob: 9d7b44b4fba046a53296efc253fe45ffa7d11f59 [file] [log] [blame]
// Copyright (c) 2012 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 "rlz/lib/machine_id.h"
#include <stddef.h>
#include "base/hash/sha1.h"
#include "base/rand_util.h"
#include "base/strings/stringprintf.h"
#include "build/chromeos_buildflags.h"
#include "rlz/lib/assert.h"
#include "rlz/lib/crc8.h"
#include "rlz/lib/string_utils.h"
namespace rlz_lib {
bool GetMachineId(std::string* machine_id) {
if (!machine_id)
return false;
// Generate a random machine Id each time this function is called. This
// prevents the RLZ server from correlating two RLZ pings from the same
// Chrome OS device.
// The Id should be 50 characters long and begin with "nonce-". Generate 23
// cryptographically random bytes, then convert to a printable string using
// 2 hex digits per byte for a string of length 46 characters. Truncate last
// hex character for 45 characters.
unsigned char bytes[23];
std::string str_bytes;
base::RandBytes(bytes, sizeof(bytes));
rlz_lib::BytesToString(bytes, sizeof(bytes), &str_bytes);
base::StringAppendF(machine_id, "NONCE%s", str_bytes.c_str());
DCHECK_EQ(50u, machine_id->length());
return true;
static std::string calculated_id;
static bool calculated = false;
if (calculated) {
*machine_id = calculated_id;
return true;
base::string16 sid_string;
int volume_id;
if (!GetRawMachineId(&sid_string, &volume_id))
return false;
if (!testing::GetMachineIdImpl(sid_string, volume_id, machine_id))
return false;
calculated = true;
calculated_id = *machine_id;
return true;
namespace testing {
bool GetMachineIdImpl(const base::string16& sid_string,
int volume_id,
std::string* machine_id) {
// The ID should be the SID hash + the Hard Drive SNo. + checksum byte.
static const int kSizeWithoutChecksum = base::kSHA1Length + sizeof(int);
std::basic_string<unsigned char> id_binary(kSizeWithoutChecksum + 1, 0);
if (!sid_string.empty()) {
// In order to be compatible with the old version of RLZ, the hash of the
// SID must be done with all the original bytes from the unicode string.
// However, the chromebase SHA1 hash function takes only an std::string as
// input, so the unicode string needs to be converted to std::string
// "as is".
size_t byte_count = sid_string.size() * sizeof(base::string16::value_type);
const char* buffer = reinterpret_cast<const char*>(sid_string.c_str());
std::string sid_string_buffer(buffer, byte_count);
// Note that digest can have embedded nulls.
std::string digest(base::SHA1HashString(sid_string_buffer));
VERIFY(digest.size() == base::kSHA1Length);
std::copy(digest.begin(), digest.end(), id_binary.begin());
// Convert from int to binary (makes big-endian).
for (size_t i = 0; i < sizeof(int); i++) {
int shift_bits = 8 * (sizeof(int) - i - 1);
id_binary[base::kSHA1Length + i] = static_cast<unsigned char>(
(volume_id >> shift_bits) & 0xFF);
// Append the checksum byte.
if (!sid_string.empty() || (0 != volume_id))
return rlz_lib::BytesToString(
id_binary.c_str(), kSizeWithoutChecksum + 1, machine_id);
} // namespace testing
} // namespace rlz_lib