| /* |
| * Copyright (C) 2015 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "auth_token_table.h" |
| |
| #include <assert.h> |
| #include <time.h> |
| |
| #include <algorithm> |
| |
| #include <keymaster/android_keymaster_utils.h> |
| #include <keymaster/logger.h> |
| |
| namespace keymaster { |
| |
| // |
| // Some trivial template wrappers around std algorithms, so they take containers not ranges. |
| // |
| template <typename Container, typename Predicate> |
| typename Container::iterator find_if(Container& container, Predicate pred) { |
| return std::find_if(container.begin(), container.end(), pred); |
| } |
| |
| template <typename Container, typename Predicate> |
| typename Container::iterator remove_if(Container& container, Predicate pred) { |
| return std::remove_if(container.begin(), container.end(), pred); |
| } |
| |
| template <typename Container> typename Container::iterator min_element(Container& container) { |
| return std::min_element(container.begin(), container.end()); |
| } |
| |
| time_t clock_gettime_raw() { |
| struct timespec time; |
| clock_gettime(CLOCK_MONOTONIC_RAW, &time); |
| return time.tv_sec; |
| } |
| |
| void AuthTokenTable::AddAuthenticationToken(const hw_auth_token_t* auth_token) { |
| Entry new_entry(auth_token, clock_function_()); |
| RemoveEntriesSupersededBy(new_entry); |
| if (entries_.size() >= max_entries_) { |
| LOG_W("Auth token table filled up; replacing oldest entry", 0); |
| *min_element(entries_) = std::move(new_entry); |
| } else { |
| entries_.push_back(std::move(new_entry)); |
| } |
| } |
| |
| inline bool is_secret_key_operation(keymaster_algorithm_t algorithm, keymaster_purpose_t purpose) { |
| if ((algorithm != KM_ALGORITHM_RSA || algorithm != KM_ALGORITHM_EC)) |
| return true; |
| if (purpose == KM_PURPOSE_SIGN || purpose == KM_PURPOSE_DECRYPT) |
| return true; |
| return false; |
| } |
| |
| inline bool KeyRequiresAuthentication(const AuthorizationSet& key_info, |
| keymaster_purpose_t purpose) { |
| keymaster_algorithm_t algorithm = KM_ALGORITHM_AES; |
| key_info.GetTagValue(TAG_ALGORITHM, &algorithm); |
| return is_secret_key_operation(algorithm, purpose) && key_info.find(TAG_NO_AUTH_REQUIRED) == -1; |
| } |
| |
| inline bool KeyRequiresAuthPerOperation(const AuthorizationSet& key_info, |
| keymaster_purpose_t purpose) { |
| keymaster_algorithm_t algorithm = KM_ALGORITHM_AES; |
| key_info.GetTagValue(TAG_ALGORITHM, &algorithm); |
| return is_secret_key_operation(algorithm, purpose) && key_info.find(TAG_AUTH_TIMEOUT) == -1; |
| } |
| |
| AuthTokenTable::Error AuthTokenTable::FindAuthorization(const AuthorizationSet& key_info, |
| keymaster_purpose_t purpose, |
| keymaster_operation_handle_t op_handle, |
| const hw_auth_token_t** found) { |
| if (!KeyRequiresAuthentication(key_info, purpose)) |
| return AUTH_NOT_REQUIRED; |
| |
| hw_authenticator_type_t auth_type = HW_AUTH_NONE; |
| key_info.GetTagValue(TAG_USER_AUTH_TYPE, &auth_type); |
| |
| std::vector<uint64_t> key_sids; |
| ExtractSids(key_info, &key_sids); |
| |
| if (KeyRequiresAuthPerOperation(key_info, purpose)) |
| return FindAuthPerOpAuthorization(key_sids, auth_type, op_handle, found); |
| else |
| return FindTimedAuthorization(key_sids, auth_type, key_info, found); |
| } |
| |
| AuthTokenTable::Error AuthTokenTable::FindAuthPerOpAuthorization( |
| const std::vector<uint64_t>& sids, hw_authenticator_type_t auth_type, |
| keymaster_operation_handle_t op_handle, const hw_auth_token_t** found) { |
| if (op_handle == 0) |
| return OP_HANDLE_REQUIRED; |
| |
| auto matching_op = find_if( |
| entries_, [&](Entry& e) { return e.token()->challenge == op_handle && !e.completed(); }); |
| |
| if (matching_op == entries_.end()) |
| return AUTH_TOKEN_NOT_FOUND; |
| |
| if (!matching_op->SatisfiesAuth(sids, auth_type)) |
| return AUTH_TOKEN_WRONG_SID; |
| |
| *found = matching_op->token(); |
| return OK; |
| } |
| |
| AuthTokenTable::Error AuthTokenTable::FindTimedAuthorization(const std::vector<uint64_t>& sids, |
| hw_authenticator_type_t auth_type, |
| const AuthorizationSet& key_info, |
| const hw_auth_token_t** found) { |
| Entry* newest_match = NULL; |
| for (auto& entry : entries_) |
| if (entry.SatisfiesAuth(sids, auth_type) && entry.is_newer_than(newest_match)) |
| newest_match = &entry; |
| |
| if (!newest_match) |
| return AUTH_TOKEN_NOT_FOUND; |
| |
| uint32_t timeout; |
| key_info.GetTagValue(TAG_AUTH_TIMEOUT, &timeout); |
| time_t now = clock_function_(); |
| if (static_cast<int64_t>(newest_match->time_received()) + timeout < static_cast<int64_t>(now)) |
| return AUTH_TOKEN_EXPIRED; |
| |
| if (key_info.GetTagValue(TAG_ALLOW_WHILE_ON_BODY)) { |
| if (static_cast<int64_t>(newest_match->time_received()) < |
| static_cast<int64_t>(last_off_body_)) { |
| return AUTH_TOKEN_EXPIRED; |
| } |
| } |
| |
| newest_match->UpdateLastUse(now); |
| *found = newest_match->token(); |
| return OK; |
| } |
| |
| void AuthTokenTable::ExtractSids(const AuthorizationSet& key_info, std::vector<uint64_t>* sids) { |
| assert(sids); |
| for (auto& param : key_info) |
| if (param.tag == TAG_USER_SECURE_ID) |
| sids->push_back(param.long_integer); |
| } |
| |
| void AuthTokenTable::RemoveEntriesSupersededBy(const Entry& entry) { |
| entries_.erase(remove_if(entries_, [&](Entry& e) { return entry.Supersedes(e); }), |
| entries_.end()); |
| } |
| |
| void AuthTokenTable::onDeviceOffBody() { |
| last_off_body_ = clock_function_(); |
| } |
| |
| void AuthTokenTable::Clear() { |
| entries_.clear(); |
| } |
| |
| bool AuthTokenTable::IsSupersededBySomeEntry(const Entry& entry) { |
| return std::any_of(entries_.begin(), entries_.end(), |
| [&](Entry& e) { return e.Supersedes(entry); }); |
| } |
| |
| void AuthTokenTable::MarkCompleted(const keymaster_operation_handle_t op_handle) { |
| auto found = find_if(entries_, [&](Entry& e) { return e.token()->challenge == op_handle; }); |
| if (found == entries_.end()) |
| return; |
| |
| assert(!IsSupersededBySomeEntry(*found)); |
| found->mark_completed(); |
| |
| if (IsSupersededBySomeEntry(*found)) |
| entries_.erase(found); |
| } |
| |
| AuthTokenTable::Entry::Entry(const hw_auth_token_t* token, time_t current_time) |
| : token_(token), time_received_(current_time), last_use_(current_time), |
| operation_completed_(token_->challenge == 0) { |
| } |
| |
| uint32_t AuthTokenTable::Entry::timestamp_host_order() const { |
| return ntoh(token_->timestamp); |
| } |
| |
| hw_authenticator_type_t AuthTokenTable::Entry::authenticator_type() const { |
| hw_authenticator_type_t result = static_cast<hw_authenticator_type_t>( |
| ntoh(static_cast<uint32_t>(token_->authenticator_type))); |
| return result; |
| } |
| |
| bool AuthTokenTable::Entry::SatisfiesAuth(const std::vector<uint64_t>& sids, |
| hw_authenticator_type_t auth_type) { |
| for (auto sid : sids) |
| if ((sid == token_->authenticator_id) || |
| (sid == token_->user_id && (auth_type & authenticator_type()) != 0)) |
| return true; |
| return false; |
| } |
| |
| void AuthTokenTable::Entry::UpdateLastUse(time_t time) { |
| this->last_use_ = time; |
| } |
| |
| bool AuthTokenTable::Entry::Supersedes(const Entry& entry) const { |
| if (!entry.completed()) |
| return false; |
| |
| return (token_->user_id == entry.token_->user_id && |
| token_->authenticator_type == entry.token_->authenticator_type && |
| token_->authenticator_type == entry.token_->authenticator_type && |
| timestamp_host_order() > entry.timestamp_host_order()); |
| } |
| |
| } // namespace keymaster |
