| // Copyright 2015 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "components/gcm_driver/crypto/gcm_key_store.h" |
| |
| #include <stddef.h> |
| |
| #include <utility> |
| |
| #include "base/containers/span.h" |
| #include "base/functional/bind.h" |
| #include "base/functional/callback.h" |
| #include "base/logging.h" |
| #include "base/metrics/histogram_macros.h" |
| #include "base/strings/string_view_util.h" |
| #include "base/task/sequenced_task_runner.h" |
| #include "components/gcm_driver/crypto/p256_key_util.h" |
| #include "components/leveldb_proto/public/proto_database_provider.h" |
| #include "components/leveldb_proto/public/shared_proto_database_client_list.h" |
| #include "crypto/evp.h" |
| #include "crypto/keypair.h" |
| #include "crypto/openssl_util.h" |
| #include "crypto/random.h" |
| #include "third_party/boringssl/src/include/openssl/bytestring.h" |
| #include "third_party/boringssl/src/include/openssl/evp.h" |
| #include "third_party/boringssl/src/include/openssl/pkcs8.h" |
| |
| namespace gcm { |
| |
| namespace { |
| |
| using EntryVectorType = |
| leveldb_proto::ProtoDatabase<EncryptionData>::KeyEntryVector; |
| |
| // Number of cryptographically secure random bytes to generate as a key pair's |
| // authentication secret. Must be at least 16 bytes. |
| const size_t kAuthSecretBytes = 16; |
| |
| std::string DatabaseKey(const std::string& app_id, |
| const std::string& authorized_entity) { |
| DCHECK_EQ(std::string::npos, app_id.find(',')); |
| DCHECK_EQ(std::string::npos, authorized_entity.find(',')); |
| DCHECK_NE("*", authorized_entity) << "Wildcards require special handling"; |
| return authorized_entity.empty() |
| ? app_id // No comma, for compatibility with existing keys. |
| : app_id + ',' + authorized_entity; |
| } |
| |
| } // namespace |
| |
| enum class GCMKeyStore::State { |
| UNINITIALIZED, |
| INITIALIZING, |
| INITIALIZED, |
| FAILED |
| }; |
| |
| GCMKeyStore::GCMKeyStore( |
| const base::FilePath& key_store_path, |
| const scoped_refptr<base::SequencedTaskRunner>& blocking_task_runner) |
| : key_store_path_(key_store_path), |
| blocking_task_runner_(blocking_task_runner), |
| state_(State::UNINITIALIZED) { |
| DCHECK(blocking_task_runner); |
| } |
| |
| GCMKeyStore::~GCMKeyStore() = default; |
| |
| void GCMKeyStore::GetKeys(const std::string& app_id, |
| const std::string& authorized_entity, |
| bool fallback_to_empty_authorized_entity, |
| KeysCallback callback) { |
| LazyInitialize( |
| base::BindOnce(&GCMKeyStore::GetKeysAfterInitialize, |
| weak_factory_.GetWeakPtr(), app_id, authorized_entity, |
| fallback_to_empty_authorized_entity, std::move(callback))); |
| } |
| |
| void GCMKeyStore::GetKeysAfterInitialize( |
| const std::string& app_id, |
| const std::string& authorized_entity, |
| bool fallback_to_empty_authorized_entity, |
| KeysCallback callback) { |
| DCHECK(state_ == State::INITIALIZED || state_ == State::FAILED); |
| bool success = false; |
| |
| if (state_ == State::INITIALIZED) { |
| auto outer_iter = key_data_.find(app_id); |
| if (outer_iter != key_data_.end()) { |
| const auto& inner_map = outer_iter->second; |
| auto inner_iter = inner_map.find(authorized_entity); |
| if (fallback_to_empty_authorized_entity && inner_iter == inner_map.end()) |
| inner_iter = inner_map.find(std::string()); |
| if (inner_iter != inner_map.end()) { |
| const auto& map_entry = inner_iter->second; |
| std::move(callback).Run(map_entry.first, map_entry.second); |
| success = true; |
| } |
| } |
| } |
| |
| if (!success) |
| std::move(callback).Run(std::nullopt /* key */, |
| std::string() /* auth_secret */); |
| } |
| |
| void GCMKeyStore::CreateKeys(const std::string& app_id, |
| const std::string& authorized_entity, |
| KeysCallback callback) { |
| LazyInitialize(base::BindOnce(&GCMKeyStore::CreateKeysAfterInitialize, |
| weak_factory_.GetWeakPtr(), app_id, |
| authorized_entity, std::move(callback))); |
| } |
| |
| void GCMKeyStore::CreateKeysAfterInitialize( |
| const std::string& app_id, |
| const std::string& authorized_entity, |
| KeysCallback callback) { |
| DCHECK(state_ == State::INITIALIZED || state_ == State::FAILED); |
| if (state_ != State::INITIALIZED) { |
| std::move(callback).Run(std::nullopt /* key */, |
| std::string() /* auth_secret */); |
| return; |
| } |
| |
| // Only allow creating new keys if no keys currently exist. Multiple Instance |
| // ID tokens can share an app_id (with different authorized entities), but |
| // InstanceID tokens can't share an app_id with a non-InstanceID registration. |
| // This invariant is necessary for the fallback_to_empty_authorized_entity |
| // mode of GetKey (needed by GCMEncryptionProvider::DecryptMessage, which |
| // can't distinguish Instance ID tokens from non-InstanceID registrations). |
| DCHECK(!key_data_.count(app_id) || |
| (!authorized_entity.empty() && |
| !key_data_[app_id].count(authorized_entity) && |
| !key_data_[app_id].count(std::string()))) |
| << "Instance ID tokens cannot share an app_id with a non-InstanceID GCM " |
| "registration"; |
| |
| auto key = crypto::keypair::PrivateKey::GenerateEcP256(); |
| |
| // Create the authentication secret, which has to be a cryptographically |
| // secure random number of at least 128 bits (16 bytes). |
| std::string auth_secret(kAuthSecretBytes, '\0'); |
| crypto::RandBytes(base::as_writable_byte_span(auth_secret)); |
| |
| // Store the keys in a new EncryptionData object. |
| EncryptionData encryption_data; |
| encryption_data.set_app_id(app_id); |
| if (!authorized_entity.empty()) |
| encryption_data.set_authorized_entity(authorized_entity); |
| encryption_data.set_auth_secret(auth_secret); |
| |
| encryption_data.set_private_key(base::as_string_view(key.ToPrivateKeyInfo())); |
| |
| // Write them immediately to our cache, so subsequent calls to |
| // {Get/Create/Remove}Keys can see them. |
| key_data_[app_id].emplace(authorized_entity, |
| std::make_pair(key, auth_secret)); |
| |
| std::unique_ptr<EntryVectorType> entries_to_save(new EntryVectorType()); |
| std::unique_ptr<std::vector<std::string>> keys_to_remove( |
| new std::vector<std::string>()); |
| |
| entries_to_save->push_back( |
| std::make_pair(DatabaseKey(app_id, authorized_entity), encryption_data)); |
| |
| database_->UpdateEntries( |
| std::move(entries_to_save), std::move(keys_to_remove), |
| base::BindOnce(&GCMKeyStore::DidStoreKeys, weak_factory_.GetWeakPtr(), |
| key, auth_secret, std::move(callback))); |
| } |
| |
| void GCMKeyStore::DidStoreKeys(crypto::keypair::PrivateKey key, |
| const std::string& auth_secret, |
| KeysCallback callback, |
| bool success) { |
| if (!success) { |
| DVLOG(1) << "Unable to store the created key in the GCM Key Store."; |
| |
| // Our cache is now inconsistent. Reject requests until restarted. |
| state_ = State::FAILED; |
| |
| std::move(callback).Run(std::nullopt /* key */, |
| std::string() /* auth_secret */); |
| return; |
| } |
| |
| std::move(callback).Run(key, auth_secret); |
| } |
| |
| void GCMKeyStore::RemoveKeys(const std::string& app_id, |
| const std::string& authorized_entity, |
| base::OnceClosure callback) { |
| LazyInitialize(base::BindOnce(&GCMKeyStore::RemoveKeysAfterInitialize, |
| weak_factory_.GetWeakPtr(), app_id, |
| authorized_entity, std::move(callback))); |
| } |
| |
| void GCMKeyStore::RemoveKeysAfterInitialize( |
| const std::string& app_id, |
| const std::string& authorized_entity, |
| base::OnceClosure callback) { |
| DCHECK(state_ == State::INITIALIZED || state_ == State::FAILED); |
| |
| const auto& outer_iter = key_data_.find(app_id); |
| if (outer_iter == key_data_.end() || state_ != State::INITIALIZED) { |
| std::move(callback).Run(); |
| return; |
| } |
| |
| std::unique_ptr<EntryVectorType> entries_to_save(new EntryVectorType()); |
| std::unique_ptr<std::vector<std::string>> keys_to_remove( |
| new std::vector<std::string>()); |
| |
| bool had_keys = false; |
| auto& inner_map = outer_iter->second; |
| for (auto it = inner_map.begin(); it != inner_map.end();) { |
| // Wildcard "*" matches all non-empty authorized entities (InstanceID only). |
| if (authorized_entity == "*" ? !it->first.empty() |
| : it->first == authorized_entity) { |
| had_keys = true; |
| |
| keys_to_remove->push_back(DatabaseKey(app_id, it->first)); |
| |
| // Clear keys immediately from our cache, so subsequent calls to |
| // {Get/Create/Remove}Keys don't see them. |
| it = inner_map.erase(it); |
| } else { |
| ++it; |
| } |
| } |
| if (!had_keys) { |
| std::move(callback).Run(); |
| return; |
| } |
| if (inner_map.empty()) |
| key_data_.erase(app_id); |
| |
| database_->UpdateEntries( |
| std::move(entries_to_save), std::move(keys_to_remove), |
| base::BindOnce(&GCMKeyStore::DidRemoveKeys, weak_factory_.GetWeakPtr(), |
| std::move(callback))); |
| } |
| |
| void GCMKeyStore::DidRemoveKeys(base::OnceClosure callback, bool success) { |
| if (!success) { |
| DVLOG(1) << "Unable to delete a key from the GCM Key Store."; |
| |
| // Our cache is now inconsistent. Reject requests until restarted. |
| state_ = State::FAILED; |
| } |
| |
| std::move(callback).Run(); |
| } |
| |
| void GCMKeyStore::DidUpgradeDatabase(bool success) { |
| if (!success) { |
| DVLOG(1) << "Unable to upgrade the GCM Key Store database."; |
| // Our cache is now inconsistent. Reject requests until restarted. |
| state_ = State::FAILED; |
| delayed_task_controller_.SetReady(); |
| return; |
| } |
| |
| database_->LoadEntries( |
| base::BindOnce(&GCMKeyStore::DidLoadKeys, weak_factory_.GetWeakPtr())); |
| } |
| |
| void GCMKeyStore::LazyInitialize(base::OnceClosure done_closure) { |
| if (delayed_task_controller_.CanRunTaskWithoutDelay()) { |
| std::move(done_closure).Run(); |
| return; |
| } |
| |
| delayed_task_controller_.AddTask(std::move(done_closure)); |
| if (state_ == State::INITIALIZING) |
| return; |
| |
| state_ = State::INITIALIZING; |
| |
| database_ = leveldb_proto::ProtoDatabaseProvider::GetUniqueDB<EncryptionData>( |
| leveldb_proto::ProtoDbType::GCM_KEY_STORE, key_store_path_, |
| blocking_task_runner_); |
| |
| database_->Init( |
| leveldb_proto::CreateSimpleOptions(), |
| base::BindOnce(&GCMKeyStore::DidInitialize, weak_factory_.GetWeakPtr())); |
| } |
| |
| void GCMKeyStore::DidInitialize(leveldb_proto::Enums::InitStatus status) { |
| bool success = status == leveldb_proto::Enums::kOK; |
| if (!success) { |
| DVLOG(1) << "Unable to initialize the GCM Key Store."; |
| state_ = State::FAILED; |
| |
| delayed_task_controller_.SetReady(); |
| return; |
| } |
| |
| database_->LoadEntries( |
| base::BindOnce(&GCMKeyStore::DidLoadKeys, weak_factory_.GetWeakPtr())); |
| } |
| |
| void GCMKeyStore::UpgradeDatabase( |
| std::unique_ptr<std::vector<EncryptionData>> entries) { |
| std::unique_ptr<EntryVectorType> entries_to_save = |
| std::make_unique<EntryVectorType>(); |
| std::unique_ptr<std::vector<std::string>> keys_to_remove = |
| std::make_unique<std::vector<std::string>>(); |
| |
| // Loop over entries, create list of database entries to overwrite. |
| for (EncryptionData& entry : *entries) { |
| if (!entry.keys_size()) |
| continue; |
| std::string decrypted_private_key; |
| if (!DecryptPrivateKey(entry.keys(0).private_key(), |
| &decrypted_private_key)) { |
| DVLOG(1) << "Unable to decrypt private key: " |
| << entry.keys(0).private_key(); |
| state_ = State::FAILED; |
| delayed_task_controller_.SetReady(); |
| return; |
| } |
| |
| entry.set_private_key(decrypted_private_key); |
| entry.clear_keys(); |
| entries_to_save->push_back(std::make_pair( |
| DatabaseKey(entry.app_id(), entry.authorized_entity()), entry)); |
| } |
| |
| database_->UpdateEntries(std::move(entries_to_save), |
| std::move(keys_to_remove), |
| base::BindOnce(&GCMKeyStore::DidUpgradeDatabase, |
| weak_factory_.GetWeakPtr())); |
| } |
| |
| void GCMKeyStore::DidLoadKeys( |
| bool success, |
| std::unique_ptr<std::vector<EncryptionData>> entries) { |
| if (!success) { |
| DVLOG(1) << "Unable to load entries into the GCM Key Store."; |
| state_ = State::FAILED; |
| |
| delayed_task_controller_.SetReady(); |
| return; |
| } |
| |
| for (const EncryptionData& entry : *entries) { |
| std::string authorized_entity; |
| if (entry.has_authorized_entity()) |
| authorized_entity = entry.authorized_entity(); |
| |
| // The old format of EncryptionData has a KeyPair in it. Previously |
| // we used to cache the key pair and auth secret in key_data_. |
| // The new code adds the pair {PrivateKey, auth_secret} to |
| // key_data_ instead. |
| if (entry.keys_size()) { |
| if (state_ == State::FAILED) |
| return; |
| |
| // Old format of EncryptionData. Upgrade database so there are no such |
| // entries. We'll reload keys from the database once this is done. |
| UpgradeDatabase(std::move(entries)); |
| return; |
| } |
| |
| if (entry.private_key().empty()) { |
| continue; |
| } |
| auto key = crypto::keypair::PrivateKey::FromPrivateKeyInfo( |
| base::as_byte_span(entry.private_key())); |
| if (!key || !key->IsEc()) { |
| continue; |
| } |
| key_data_[entry.app_id()].emplace( |
| authorized_entity, std::make_pair(*key, entry.auth_secret())); |
| } |
| |
| state_ = State::INITIALIZED; |
| |
| delayed_task_controller_.SetReady(); |
| } |
| |
| bool GCMKeyStore::DecryptPrivateKey(const std::string& to_decrypt_str, |
| std::string* decrypted) { |
| auto to_decrypt = base::as_byte_span(to_decrypt_str); |
| |
| crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE); |
| CBS cbs; |
| CBS_init(&cbs, to_decrypt.data(), to_decrypt.size()); |
| bssl::UniquePtr<EVP_PKEY> pkey( |
| PKCS8_parse_encrypted_private_key(&cbs, "", 0)); |
| |
| // Hack for reading keys generated by an older version of the OpenSSL code. |
| // Some implementations encode the empty password as "\0\0" (passwords are |
| // normally encoded in big-endian UCS-2 with a NUL terminator) and some |
| // encode as the empty string. PKCS8_parse_encrypted_private_key |
| // distinguishes the two by whether the password is nullptr. |
| if (!pkey) { |
| CBS_init(&cbs, to_decrypt.data(), to_decrypt.size()); |
| pkey.reset(PKCS8_parse_encrypted_private_key(&cbs, nullptr, 0)); |
| } |
| |
| if (!pkey || CBS_len(&cbs) != 0 || EVP_PKEY_id(pkey.get()) != EVP_PKEY_EC) { |
| return false; |
| } |
| |
| auto decrypted_vec = crypto::evp::PrivateKeyToBytes(pkey.get()); |
| decrypted->assign(decrypted_vec.begin(), decrypted_vec.end()); |
| return true; |
| } |
| |
| } // namespace gcm |