mirror of
https://github.com/kidfromjupiter/nearby.git
synced 2026-09-15 15:16:12 -04:00
127 lines
4.3 KiB
C++
127 lines
4.3 KiB
C++
// Copyright 2022 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "sharing/certificates/common.h"
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#include <stddef.h>
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#include <stdint.h>
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#include <limits>
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#include <memory>
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#include <ostream>
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#include <string>
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#include <vector>
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#include "absl/time/time.h"
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#include "absl/types/span.h"
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#include "internal/crypto_cros/encryptor.h"
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#include "internal/crypto_cros/hkdf.h"
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#include "internal/crypto_cros/symmetric_key.h"
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#include "internal/platform/crypto.h"
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#include "sharing/certificates/constants.h"
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#include "sharing/internal/public/logging.h"
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namespace nearby {
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namespace sharing {
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bool IsNearbyShareCertificateExpired(absl::Time current_time,
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absl::Time not_after,
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bool use_public_certificate_tolerance) {
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absl::Duration tolerance =
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use_public_certificate_tolerance
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? kNearbySharePublicCertificateValidityBoundOffsetTolerance
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: absl::ZeroDuration();
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return current_time >= not_after + tolerance;
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}
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bool IsNearbyShareCertificateWithinValidityPeriod(
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absl::Time current_time, absl::Time not_before, absl::Time not_after,
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bool use_public_certificate_tolerance) {
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absl::Duration tolerance =
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use_public_certificate_tolerance
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? kNearbySharePublicCertificateValidityBoundOffsetTolerance
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: absl::ZeroDuration();
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return current_time >= not_before - tolerance &&
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!IsNearbyShareCertificateExpired(current_time, not_after,
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use_public_certificate_tolerance);
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}
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std::vector<uint8_t> DeriveNearbyShareKey(absl::Span<const uint8_t> key,
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size_t new_num_bytes) {
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return crypto::HkdfSha256(key,
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/*salt=*/absl::Span<const uint8_t>(),
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/*info=*/absl::Span<const uint8_t>(),
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new_num_bytes);
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}
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std::vector<uint8_t> ComputeAuthenticationTokenHash(
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absl::Span<const uint8_t> authentication_token,
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absl::Span<const uint8_t> secret_key) {
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return crypto::HkdfSha256(authentication_token, secret_key,
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/*info=*/absl::Span<const uint8_t>(),
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kNearbyShareNumBytesAuthenticationTokenHash);
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}
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std::vector<uint8_t> GenerateRandomBytes(size_t num_bytes) {
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std::vector<uint8_t> bytes(num_bytes);
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RandBytes(absl::Span<uint8_t>(bytes));
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return bytes;
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}
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std::unique_ptr<crypto::Encryptor> CreateNearbyShareCtrEncryptor(
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const crypto::SymmetricKey* secret_key, absl::Span<const uint8_t> salt) {
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DCHECK(secret_key);
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DCHECK_EQ(kNearbyShareNumBytesSecretKey, secret_key->key().size());
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DCHECK_EQ(kNearbyShareNumBytesMetadataEncryptionKeySalt, salt.size());
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auto encryptor = std::make_unique<crypto::Encryptor>();
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// For CTR mode, the iv input to Init() must be empty. Instead, the iv is
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// set via SetCounter().
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if (!encryptor->Init(secret_key, crypto::Encryptor::Mode::CTR,
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/*iv=*/absl::Span<const uint8_t>())) {
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LOG(ERROR) << "Encryptor could not be initialized.";
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return nullptr;
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}
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std::vector<uint8_t> iv =
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DeriveNearbyShareKey(salt, kNearbyShareNumBytesAesCtrIv);
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if (!encryptor->SetCounter(iv)) {
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LOG(ERROR) << "Could not set encryptor counter.";
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return nullptr;
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}
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return encryptor;
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}
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absl::Time FromJavaTime(int64_t ms_since_epoch) {
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return absl::UnixEpoch() + absl::Milliseconds(ms_since_epoch);
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}
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int64_t ToJavaTime(absl::Time time) {
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// Preserve 0 so the invalid result doesn't depend on the platform.
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if (time == absl::InfiniteFuture()) {
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return std::numeric_limits<int64_t>::max();
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} else if (time == absl::InfinitePast()) {
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return std::numeric_limits<int64_t>::min();
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} else {
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return (time - absl::UnixEpoch()) / absl::Milliseconds(1);
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}
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}
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} // namespace sharing
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} // namespace nearby
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