content/browser/bluetooth/bluetooth_allowed_devices_map.cc

// 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 "content/browser/bluetooth/bluetooth_allowed_devices_map.h"

#include <vector>

#include "base/base64.h"
#include "base/logging.h"
#include "base/stl_util.h"
#include "base/strings/string_util.h"
#include "content/common/bluetooth/bluetooth_scan_filter.h"
#include "crypto/random.h"
#include "device/bluetooth/bluetooth_uuid.h"

using device::BluetoothUUID;

namespace content {

namespace {
const size_t kIdLength = 16 /* 128bits */;

std::string GetBase64Id() {
  std::string bytes(
      kIdLength + 1 /* to avoid bytes being reallocated by WriteInto */, '\0');

  crypto::RandBytes(
      base::WriteInto(&bytes /* str */, kIdLength + 1 /* length_with_null */),
      kIdLength);

  base::Base64Encode(bytes, &bytes);

  return bytes;
}
}  // namespace

BluetoothAllowedDevicesMap::BluetoothAllowedDevicesMap() {}
BluetoothAllowedDevicesMap::~BluetoothAllowedDevicesMap() {}

const std::string& BluetoothAllowedDevicesMap::AddDevice(
    const url::Origin& origin,
    const std::string& device_address,
    const std::vector<BluetoothScanFilter>& filters,
    const std::vector<BluetoothUUID>& optional_services) {
  VLOG(1) << "Adding a device to Map of Allowed Devices.";

  // "Unique" Origins generate the same key in maps. The set of "unique"
  // Origins that generate the same key does not intersect the set of
  // potentially trustworthy origins; since Bluetooth is only available for
  // potntially trustworthy origins we should never receive a request from a
  // "unique" Origin.
  // See url::Origin for what constitutes a "unique" Origin and the
  // Secure Contexts spec for what constitutes a Trusworthy Origin:
  // https://w3c.github.io/webappsec-secure-contexts/
  CHECK(!origin.unique());

  if (ContainsKey(origin_to_device_address_to_id_map_[origin],
                  device_address)) {
    VLOG(1) << "Device already in map of allowed devices.";
    return origin_to_device_address_to_id_map_[origin][device_address];
  }
  const std::string device_id = GenerateDeviceId(origin);
  VLOG(1) << "Id generated for device: " << device_id;

  origin_to_device_address_to_id_map_[origin][device_address] = device_id;
  origin_to_device_id_to_address_map_[origin][device_id] = device_address;
  origin_to_device_id_to_services_map_[origin][device_id] =
      UnionOfServices(filters, optional_services);

  return origin_to_device_address_to_id_map_[origin][device_address];
}

void BluetoothAllowedDevicesMap::RemoveDevice(
    const url::Origin& origin,
    const std::string& device_address) {
  const std::string device_id = GetDeviceId(origin, device_address);
  DCHECK(!device_id.empty());

  // 1. Remove from all three maps.
  CHECK(origin_to_device_address_to_id_map_[origin].erase(device_address));
  CHECK(origin_to_device_id_to_address_map_[origin].erase(device_id));
  CHECK(origin_to_device_id_to_services_map_[origin].erase(device_id));

  // 2. Remove empty map for origin.
  if (origin_to_device_address_to_id_map_[origin].empty()) {
    CHECK(origin_to_device_address_to_id_map_.erase(origin));
    CHECK(origin_to_device_id_to_address_map_.erase(origin));
    CHECK(origin_to_device_id_to_services_map_.erase(origin));
  }
}

const std::string& BluetoothAllowedDevicesMap::GetDeviceId(
    const url::Origin& origin,
    const std::string& device_address) {
  auto address_map_iter = origin_to_device_address_to_id_map_.find(origin);
  if (address_map_iter == origin_to_device_address_to_id_map_.end()) {
    return base::EmptyString();
  }

  const auto& device_address_to_id_map = address_map_iter->second;

  auto id_iter = device_address_to_id_map.find(device_address);
  if (id_iter == device_address_to_id_map.end()) {
    return base::EmptyString();
  }
  return id_iter->second;
}

const std::string& BluetoothAllowedDevicesMap::GetDeviceAddress(
    const url::Origin& origin,
    const std::string& device_id) {
  auto id_map_iter = origin_to_device_id_to_address_map_.find(origin);
  if (id_map_iter == origin_to_device_id_to_address_map_.end()) {
    return base::EmptyString();
  }

  const auto& device_id_to_address_map = id_map_iter->second;

  auto id_iter = device_id_to_address_map.find(device_id);

  return id_iter == device_id_to_address_map.end() ? base::EmptyString()
                                                   : id_iter->second;
}

std::string BluetoothAllowedDevicesMap::GenerateDeviceId(
    const url::Origin& origin) {
  std::string device_id = GetBase64Id();
  auto id_map_iter = origin_to_device_id_to_address_map_.find(origin);
  if (id_map_iter == origin_to_device_id_to_address_map_.end()) {
    return device_id;
  }
  while (ContainsKey(id_map_iter->second, device_id)) {
    LOG(WARNING) << "Generated repeated id.";
    device_id = GetBase64Id();
  }
  return device_id;
}

std::set<std::string> BluetoothAllowedDevicesMap::UnionOfServices(
    const std::vector<BluetoothScanFilter>& filters,
    const std::vector<BluetoothUUID>& optional_services) {
  std::set<std::string> unionOfServices;
  for (const auto& filter : filters) {
    for (const BluetoothUUID& uuid : filter.services) {
      unionOfServices.insert(uuid.canonical_value());
    }
  }
  for (const BluetoothUUID& uuid : optional_services) {
    unionOfServices.insert(uuid.canonical_value());
  }
  return unionOfServices;
}

}  // namespace content