mirror of
https://github.com/kidfromjupiter/nearby.git
synced 2026-09-15 07:06:11 -04:00
134 lines
4.2 KiB
C++
134 lines
4.2 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 "presence/implementation/ldt.h"
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#include <algorithm>
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#include <optional>
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#include <string>
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#include "absl/status/status.h"
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#include "absl/status/statusor.h"
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#include "absl/strings/str_format.h"
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#include "absl/strings/string_view.h"
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#include <openssl/aes.h>
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#if USE_RUST_LDT == 1
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#include "third_party/nearby_rust/presence/np_ffi/include/np_ldt.h"
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#else
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#include "presence/implementation/np_ldt.h"
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#endif /* USE_RUST_LDT */
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namespace nearby {
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namespace presence {
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namespace {
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// NP LDT library says that 0 is returned when `NpLdtCreate()` fails.
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constexpr NpLdtHandle kInvalidLdtHandle = static_cast<NpLdtHandle>(0);
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template <class T>
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T FromStringView(absl::string_view data) {
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T result{
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.bytes = {0},
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};
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memcpy(result.bytes, data.data(),
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std::min(sizeof(result.bytes), data.size()));
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return result;
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}
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struct AesContext {
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AES_KEY encryption_key;
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AES_KEY decryption_key;
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};
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NpLdtAesCipherHandle AesCreateCipher(NpLdtAes128Key key) {
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AesContext* ctx = new AesContext();
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AES_set_encrypt_key(key.bytes, 128, &ctx->encryption_key);
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AES_set_decrypt_key(key.bytes, 128, &ctx->decryption_key);
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// The caller takes ownership and they must call `AesCloseCipher` eventually.
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return ctx;
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}
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int32_t AesCloseCipher(NpLdtAesCipherHandle handle) {
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AesContext* ctx = reinterpret_cast<AesContext*>(handle);
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delete ctx;
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return 0;
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}
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void AesEncrypt(NpLdtAesCipherHandle handle, NpLdtAesBlock* block) {
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AesContext* ctx = reinterpret_cast<AesContext*>(handle);
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AES_encrypt(block->bytes, block->bytes, &ctx->encryption_key);
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}
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void AesDecrypt(NpLdtAesCipherHandle handle, NpLdtAesBlock* block) {
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AesContext* ctx = reinterpret_cast<AesContext*>(handle);
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AES_decrypt(block->bytes, block->bytes, &ctx->decryption_key);
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}
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} // namespace
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LdtEncryptor::LdtEncryptor(LdtEncryptor&& other)
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: ldt_handle_(other.ldt_handle_) {
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other.ldt_handle_ = kInvalidLdtHandle;
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}
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LdtEncryptor::~LdtEncryptor() {
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if (ldt_handle_ != kInvalidLdtHandle) {
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NpLdtClose(ldt_handle_);
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}
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}
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absl::StatusOr<LdtEncryptor> LdtEncryptor::Create(
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absl::string_view key_seed, absl::string_view known_hmac) {
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NpLdtHandle handle =
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NpLdtCreate({.create_cipher = AesCreateCipher,
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.close_cipher = AesCloseCipher,
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.encrypt = AesEncrypt,
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.decrypt = AesDecrypt},
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FromStringView<NpLdtKeySeed>(key_seed),
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FromStringView<NpMetadataKeyHmac>(known_hmac));
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if (handle == kInvalidLdtHandle) {
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return absl::UnavailableError("Failed to create LDT encryptor");
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}
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return LdtEncryptor(handle);
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}
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absl::StatusOr<std::string> LdtEncryptor::Encrypt(absl::string_view data,
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absl::string_view salt) {
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std::string encrypted = std::string(data);
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NP_LDT_RESULT result =
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NpLdtEncrypt(ldt_handle_, reinterpret_cast<uint8_t*>(encrypted.data()),
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encrypted.size(), FromStringView<NpLdtSalt>(salt));
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if (result == NP_LDT_SUCCESS) {
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return encrypted;
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}
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return absl::InternalError(
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absl::StrFormat("LDT encryption failed, errorcode %d", result));
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}
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absl::StatusOr<std::string> LdtEncryptor::DecryptAndVerify(
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absl::string_view data, absl::string_view salt) {
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std::string encrypted = std::string(data);
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NP_LDT_RESULT result = NpLdtDecryptAndVerify(
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ldt_handle_, reinterpret_cast<uint8_t*>(encrypted.data()),
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encrypted.size(), FromStringView<NpLdtSalt>(salt));
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if (result == NP_LDT_SUCCESS) {
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return encrypted;
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}
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return absl::InternalError(
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absl::StrFormat("LDT encryption failed, errorcode %d", result));
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}
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} // namespace presence
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} // namespace nearby
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