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/*
** Copyright 2018, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
** http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
#include <keymasterV4_0/Keymaster.h>
#include <iomanip>
#include <android-base/logging.h>
#include <android/hidl/manager/1.0/IServiceManager.h>
#include <keymasterV4_0/Keymaster3.h>
#include <keymasterV4_0/Keymaster4.h>
#include <keymasterV4_0/key_param_output.h>
#include <keymasterV4_0/keymaster_utils.h>
namespace android {
namespace hardware {
template <class T>
std::ostream& operator<<(std::ostream& os, const hidl_vec<T>& vec) {
os << "{ ";
if (vec.size()) {
for (size_t i = 0; i < vec.size() - 1; ++i) os << vec[i] << ", ";
os << vec[vec.size() - 1];
}
os << " }";
return os;
}
std::ostream& operator<<(std::ostream& os, const hidl_vec<uint8_t>& vec) {
std::ios_base::fmtflags flags(os.flags());
os << std::setw(2) << std::setfill('0') << std::hex;
for (uint8_t c : vec) os << static_cast<int>(c);
os.flags(flags);
return os;
}
template <size_t N>
std::ostream& operator<<(std::ostream& os, const hidl_array<uint8_t, N>& vec) {
std::ios_base::fmtflags flags(os.flags());
os << std::setw(2) << std::setfill('0') << std::hex;
for (size_t i = 0; i < N; ++i) os << static_cast<int>(vec[i]);
os.flags(flags);
return os;
}
namespace keymaster {
namespace V4_0 {
std::ostream& operator<<(std::ostream& os, const HmacSharingParameters& params) {
// Note that by design, although seed and nonce are used to compute a secret, they are
// not secrets and it's just fine to log them.
os << "(seed: " << params.seed << ", nonce: " << params.nonce << ')';
return os;
}
namespace support {
using ::android::sp;
using ::android::hidl::manager::V1_0::IServiceManager;
std::ostream& operator<<(std::ostream& os, const Keymaster& keymaster) {
auto& version = keymaster.halVersion();
os << version.keymasterName << " from " << version.authorName
<< " SecurityLevel: " << toString(version.securityLevel)
<< " HAL: " << keymaster.descriptor() << "/" << keymaster.instanceName();
return os;
}
template <typename Wrapper>
std::vector<std::unique_ptr<Keymaster>> enumerateDevices(
const sp<IServiceManager>& serviceManager) {
Keymaster::KeymasterSet result;
bool foundDefault = false;
auto& descriptor = Wrapper::WrappedIKeymasterDevice::descriptor;
serviceManager->listByInterface(descriptor, [&](const hidl_vec<hidl_string>& names) {
for (auto& name : names) {
if (name == "default") foundDefault = true;
auto device = Wrapper::WrappedIKeymasterDevice::getService(name);
CHECK(device) << "Failed to get service for " << descriptor << " with interface name "
<< name;
result.push_back(std::unique_ptr<Keymaster>(new Wrapper(device, name)));
}
});
if (!foundDefault) {
// "default" wasn't provided by listByInterface. Maybe there's a passthrough
// implementation.
auto device = Wrapper::WrappedIKeymasterDevice::getService("default");
if (device) result.push_back(std::unique_ptr<Keymaster>(new Wrapper(device, "default")));
}
return result;
}
Keymaster::KeymasterSet Keymaster::enumerateAvailableDevices() {
auto serviceManager = IServiceManager::getService();
CHECK(serviceManager) << "Could not retrieve ServiceManager";
auto km4s = enumerateDevices<Keymaster4>(serviceManager);
auto km3s = enumerateDevices<Keymaster3>(serviceManager);
auto result = std::move(km4s);
result.insert(result.end(), std::make_move_iterator(km3s.begin()),
std::make_move_iterator(km3s.end()));
std::sort(result.begin(), result.end(),
[](auto& a, auto& b) { return a->halVersion() > b->halVersion(); });
size_t i = 1;
LOG(INFO) << "List of Keymaster HALs found:";
for (auto& hal : result) LOG(INFO) << "Keymaster HAL #" << i++ << ": " << *hal;
return result;
}
static hidl_vec<HmacSharingParameters> getHmacParameters(
const Keymaster::KeymasterSet& keymasters) {
std::vector<HmacSharingParameters> params_vec;
params_vec.reserve(keymasters.size());
for (auto& keymaster : keymasters) {
if (keymaster->halVersion().majorVersion < 4) continue;
auto rc = keymaster->getHmacSharingParameters([&](auto error, auto& params) {
CHECK(error == ErrorCode::OK)
<< "Failed to get HMAC parameters from " << *keymaster << " error " << error;
params_vec.push_back(params);
});
CHECK(rc.isOk()) << "Failed to communicate with " << *keymaster
<< " error: " << rc.description();
}
std::sort(params_vec.begin(), params_vec.end());
return params_vec;
}
static void computeHmac(const Keymaster::KeymasterSet& keymasters,
const hidl_vec<HmacSharingParameters>& params) {
if (!params.size()) return;
hidl_vec<uint8_t> sharingCheck;
bool firstKeymaster = true;
LOG(DEBUG) << "Computing HMAC with params " << params;
for (auto& keymaster : keymasters) {
if (keymaster->halVersion().majorVersion < 4) continue;
LOG(DEBUG) << "Computing HMAC for " << *keymaster;
auto rc = keymaster->computeSharedHmac(
params, [&](ErrorCode error, const hidl_vec<uint8_t>& curSharingCheck) {
CHECK(error == ErrorCode::OK)
<< "Failed to get HMAC parameters from " << *keymaster << " error " << error;
if (firstKeymaster) {
sharingCheck = curSharingCheck;
firstKeymaster = false;
}
CHECK(curSharingCheck == sharingCheck)
<< "HMAC computation failed for " << *keymaster //
<< " Expected: " << sharingCheck //
<< " got: " << curSharingCheck;
});
CHECK(rc.isOk()) << "Failed to communicate with " << *keymaster
<< " error: " << rc.description();
}
}
void Keymaster::performHmacKeyAgreement(const KeymasterSet& keymasters) {
computeHmac(keymasters, getHmacParameters(keymasters));
}
} // namespace support
} // namespace V4_0
} // namespace keymaster
} // namespace hardware
} // namespace android
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