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/**
* Copyright (C) 2017 MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/platform/basic.h"
#include "mongo/db/time_proof_service.h"
#include "mongo/base/status.h"
#include "mongo/db/logical_time.h"
#include "mongo/platform/random.h"
namespace mongo {
/**
* This value defines the range of times that match the cache. It is assumed that the cluster times
* are staying within the range so the range size is defined by the mask. This assumes that the
* implementation has a form or high 32 bit: secs low 32 bit: increment.
*/
const uint64_t kRangeMask = 0x0000'0000'0000'FFFF;
TimeProofService::Key TimeProofService::generateRandomKey() {
// SecureRandom only produces 64-bit numbers, so 3 is the minimum for 20 random bytes.
const size_t kRandomNumbers = 3;
std::array<std::int64_t, kRandomNumbers> keyBuffer;
std::unique_ptr<SecureRandom> rng(SecureRandom::create());
std::generate(keyBuffer.begin(), keyBuffer.end(), [&] { return rng->nextInt64(); });
return fassertStatusOK(40384,
SHA1Block::fromBuffer(reinterpret_cast<std::uint8_t*>(keyBuffer.data()),
SHA1Block::kHashLength));
}
TimeProofService::TimeProof TimeProofService::getProof(LogicalTime time, const Key& key) {
stdx::lock_guard<stdx::mutex> lk(_cacheMutex);
if (_cache && _cache->hasProof(time, key)) {
return _cache->_proof;
}
auto timeCeil = LogicalTime(Timestamp(time.asTimestamp().asULL() | kRangeMask));
auto unsignedTimeArray = timeCeil.toUnsignedArray();
// update cache
_cache =
CacheEntry(SHA1Block::computeHmac(
key.data(), key.size(), unsignedTimeArray.data(), unsignedTimeArray.size()),
timeCeil,
key);
return _cache->_proof;
}
Status TimeProofService::checkProof(LogicalTime time, const TimeProof& proof, const Key& key) {
auto myProof = getProof(time, key);
if (myProof != proof) {
return Status(ErrorCodes::TimeProofMismatch, "Proof does not match the cluster time");
}
return Status::OK();
}
void TimeProofService::resetCache() {
stdx::lock_guard<stdx::mutex> lk(_cacheMutex);
if (_cache) {
_cache = boost::none;
}
}
} // namespace mongo
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