| // Copyright 2020 The Chromium OS Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "cryptohome/auth_session.h" |
| |
| #include <memory> |
| #include <string> |
| #include <utility> |
| |
| #include <base/logging.h> |
| #include <brillo/cryptohome.h> |
| #include <cryptohome/scrypt_verifier.h> |
| |
| #include "cryptohome/keyset_management.h" |
| #include "cryptohome/password_auth_factor.h" |
| #include "cryptohome/storage/mount_utils.h" |
| #include "cryptohome/vault_keyset.h" |
| |
| using brillo::cryptohome::home::SanitizeUserName; |
| |
| namespace cryptohome { |
| |
| // Size of the values used serialization of UnguessableToken. |
| constexpr int kSizeOfSerializedValueInToken = sizeof(uint64_t); |
| // Number of uint64 used serialization of UnguessableToken. |
| constexpr int kNumberOfSerializedValuesInToken = 2; |
| // Offset where the high value is used in Serialized string. |
| constexpr int kHighTokenOffset = 0; |
| // Offset where the low value is used in Serialized string. |
| constexpr int kLowTokenOffset = kSizeOfSerializedValueInToken; |
| // AuthSession will time out if it is active after this time interval. |
| constexpr base::TimeDelta kAuthSessionTimeoutInMinutes = |
| base::TimeDelta::FromMinutes(5); |
| |
| AuthSession::AuthSession( |
| std::string username, |
| unsigned int flags, |
| base::OnceCallback<void(const base::UnguessableToken&)> on_timeout, |
| KeysetManagement* keyset_management) |
| : username_(username), |
| on_timeout_(std::move(on_timeout)), |
| keyset_management_(keyset_management) { |
| token_ = base::UnguessableToken::Create(); |
| ProcessFlags(flags); |
| timer_.Start(FROM_HERE, kAuthSessionTimeoutInMinutes, |
| base::BindOnce(&AuthSession::AuthSessionTimedOut, |
| base::Unretained(this))); |
| user_exists_ = keyset_management_->UserExists(SanitizeUserName(username_)); |
| if (user_exists_) |
| keyset_management_->GetVaultKeysetLabelsAndData(SanitizeUserName(username_), |
| &key_label_data_); |
| } |
| |
| AuthSession::~AuthSession() = default; |
| |
| void AuthSession::ProcessFlags(unsigned int flags) { |
| is_kiosk_user_ = |
| flags & user_data_auth::AuthSessionFlags::AUTH_SESSION_FLAGS_KIOSK_USER; |
| is_ephemeral_user_ = |
| flags & |
| user_data_auth::AuthSessionFlags::AUTH_SESSION_FLAGS_EPHEMERAL_USER; |
| LOG(INFO) << "AuthSession Flags: is_ephemeral_user_ " << is_ephemeral_user_ |
| << " is_kiosk_user_ " << is_kiosk_user_; |
| } |
| |
| void AuthSession::AuthSessionTimedOut() { |
| status_ = AuthStatus::kAuthStatusTimedOut; |
| // After this call back to |UserDataAuth|, |this| object will be deleted. |
| std::move(on_timeout_).Run(token_); |
| } |
| |
| user_data_auth::CryptohomeErrorCode AuthSession::AddCredentials( |
| const user_data_auth::AddCredentialsRequest& request) { |
| MountError code; |
| CHECK(request.authorization().key().has_data()); |
| auto credentials = GetCredentials(request.authorization(), &code); |
| if (!credentials) { |
| return MountErrorToCryptohomeError(code); |
| } |
| if (user_exists_) { |
| // Check the privileges to ensure Add is allowed. |
| // Keys without extended data are considered fully privileged. |
| if (auth_factor_->vault_keyset().HasKeyData() && |
| !auth_factor_->vault_keyset().GetKeyData().privileges().add()) { |
| LOG(WARNING) << "Add Credentials: no add() privilege"; |
| return user_data_auth::CRYPTOHOME_ERROR_AUTHORIZATION_KEY_DENIED; |
| } |
| |
| return keyset_management_->AddKeyset(*credentials, |
| auth_factor_->vault_keyset()); |
| } |
| |
| user_data_auth::CryptohomeErrorCode errorCode = |
| user_data_auth::CRYPTOHOME_ERROR_NOT_SET; |
| // An assumption here is that keyset management saves the user keys on disk. |
| if (!keyset_management_->AddInitialKeyset(*credentials)) { |
| errorCode = user_data_auth::CRYPTOHOME_ADD_CREDENTIALS_FAILED; |
| } |
| return errorCode; |
| } |
| |
| user_data_auth::CryptohomeErrorCode AuthSession::Authenticate( |
| const cryptohome::AuthorizationRequest& authorization_request) { |
| MountError code; |
| auto credentials = GetCredentials(authorization_request, &code); |
| if (!credentials) { |
| return MountErrorToCryptohomeError(code); |
| } |
| if (authorization_request.key().data().type() == KeyData::KEY_TYPE_PASSWORD) { |
| auth_factor_ = std::make_unique<PasswordAuthFactor>(keyset_management_); |
| } |
| |
| bool authenticated = auth_factor_->AuthenticateAuthFactor( |
| *credentials, is_ephemeral_user_, &code); |
| if (authenticated) { |
| status_ = AuthStatus::kAuthStatusAuthenticated; |
| } |
| return MountErrorToCryptohomeError(code); |
| } |
| |
| std::unique_ptr<CredentialVerifier> AuthSession::TakeCredentialVerifier() { |
| return auth_factor_->TakeCredentialVerifier(); |
| } |
| |
| // static |
| base::Optional<std::string> AuthSession::GetSerializedStringFromToken( |
| const base::UnguessableToken& token) { |
| if (token == base::UnguessableToken::Null()) { |
| LOG(ERROR) << "Invalid UnguessableToken given"; |
| return base::nullopt; |
| } |
| std::string serialized_token; |
| serialized_token.resize(kSizeOfSerializedValueInToken * |
| kNumberOfSerializedValuesInToken); |
| uint64_t high = token.GetHighForSerialization(); |
| uint64_t low = token.GetLowForSerialization(); |
| memcpy(&serialized_token[kHighTokenOffset], &high, sizeof(high)); |
| memcpy(&serialized_token[kLowTokenOffset], &low, sizeof(low)); |
| return serialized_token; |
| } |
| |
| // static |
| base::Optional<base::UnguessableToken> |
| AuthSession::GetTokenFromSerializedString(const std::string& serialized_token) { |
| if (serialized_token.size() != |
| kSizeOfSerializedValueInToken * kNumberOfSerializedValuesInToken) { |
| LOG(ERROR) << "Incorrect serialized string size"; |
| return base::nullopt; |
| } |
| uint64_t high, low; |
| memcpy(&high, &serialized_token[kHighTokenOffset], sizeof(high)); |
| memcpy(&low, &serialized_token[kLowTokenOffset], sizeof(low)); |
| return base::UnguessableToken::Deserialize(high, low); |
| } |
| |
| std::unique_ptr<Credentials> AuthSession::GetCredentials( |
| const cryptohome::AuthorizationRequest& authorization_request, |
| MountError* error) { |
| auto credentials = std::make_unique<Credentials>( |
| username_, brillo::SecureBlob(authorization_request.key().secret())); |
| credentials->set_key_data(authorization_request.key().data()); |
| |
| if (is_kiosk_user_) { |
| brillo::SecureBlob public_mount_passkey = |
| keyset_management_->GetPublicMountPassKey(username_); |
| if (public_mount_passkey.empty()) { |
| LOG(ERROR) << "Could not get public mount passkey."; |
| *error = MountError::MOUNT_ERROR_KEY_FAILURE; |
| return nullptr; |
| } |
| credentials->set_passkey(public_mount_passkey); |
| } |
| |
| return credentials; |
| } |
| |
| } // namespace cryptohome |