/*
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* Copyright (C) 2015 The Android Open Source Project
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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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* http://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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*/
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#define LOG_TAG "keystore"
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#include "auth_token_table.h"
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#include <assert.h>
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#include <time.h>
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#include <algorithm>
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#include <log/log.h>
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namespace keystore {
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template <typename IntType, uint32_t byteOrder> struct choose_hton;
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template <typename IntType> struct choose_hton<IntType, __ORDER_LITTLE_ENDIAN__> {
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inline static IntType hton(const IntType& value) {
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IntType result = 0;
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const unsigned char* inbytes = reinterpret_cast<const unsigned char*>(&value);
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unsigned char* outbytes = reinterpret_cast<unsigned char*>(&result);
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for (int i = sizeof(IntType) - 1; i >= 0; --i) {
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*(outbytes++) = inbytes[i];
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}
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return result;
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}
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};
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template <typename IntType> struct choose_hton<IntType, __ORDER_BIG_ENDIAN__> {
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inline static IntType hton(const IntType& value) { return value; }
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};
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template <typename IntType> inline IntType hton(const IntType& value) {
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return choose_hton<IntType, __BYTE_ORDER__>::hton(value);
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}
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template <typename IntType> inline IntType ntoh(const IntType& value) {
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// same operation and hton
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return choose_hton<IntType, __BYTE_ORDER__>::hton(value);
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}
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//
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// Some trivial template wrappers around std algorithms, so they take containers not ranges.
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//
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template <typename Container, typename Predicate>
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typename Container::iterator find_if(Container& container, Predicate pred) {
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return std::find_if(container.begin(), container.end(), pred);
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}
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template <typename Container, typename Predicate>
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typename Container::iterator remove_if(Container& container, Predicate pred) {
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return std::remove_if(container.begin(), container.end(), pred);
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}
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template <typename Container> typename Container::iterator min_element(Container& container) {
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return std::min_element(container.begin(), container.end());
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}
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time_t clock_gettime_raw() {
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struct timespec time;
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clock_gettime(CLOCK_MONOTONIC_RAW, &time);
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return time.tv_sec;
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}
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void AuthTokenTable::AddAuthenticationToken(HardwareAuthToken&& auth_token) {
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Entry new_entry(std::move(auth_token), clock_function_());
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// STOPSHIP: debug only, to be removed
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ALOGD("AddAuthenticationToken: timestamp = %llu, time_received = %lld",
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static_cast<unsigned long long>(new_entry.token().timestamp),
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static_cast<long long>(new_entry.time_received()));
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std::lock_guard<std::mutex> lock(entries_mutex_);
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RemoveEntriesSupersededBy(new_entry);
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if (entries_.size() >= max_entries_) {
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ALOGW("Auth token table filled up; replacing oldest entry");
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*min_element(entries_) = std::move(new_entry);
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} else {
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entries_.push_back(std::move(new_entry));
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}
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}
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inline bool is_secret_key_operation(Algorithm algorithm, KeyPurpose purpose) {
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if ((algorithm != Algorithm::RSA && algorithm != Algorithm::EC)) return true;
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if (purpose == KeyPurpose::SIGN || purpose == KeyPurpose::DECRYPT) return true;
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return false;
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}
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inline bool KeyRequiresAuthentication(const AuthorizationSet& key_info, KeyPurpose purpose) {
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auto algorithm = defaultOr(key_info.GetTagValue(TAG_ALGORITHM), Algorithm::AES);
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return is_secret_key_operation(algorithm, purpose) &&
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key_info.find(Tag::NO_AUTH_REQUIRED) == -1;
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}
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inline bool KeyRequiresAuthPerOperation(const AuthorizationSet& key_info, KeyPurpose purpose) {
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auto algorithm = defaultOr(key_info.GetTagValue(TAG_ALGORITHM), Algorithm::AES);
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return is_secret_key_operation(algorithm, purpose) && key_info.find(Tag::AUTH_TIMEOUT) == -1;
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}
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std::tuple<AuthTokenTable::Error, HardwareAuthToken>
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AuthTokenTable::FindAuthorization(const AuthorizationSet& key_info, KeyPurpose purpose,
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uint64_t op_handle) {
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std::lock_guard<std::mutex> lock(entries_mutex_);
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if (!KeyRequiresAuthentication(key_info, purpose)) return {AUTH_NOT_REQUIRED, {}};
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auto auth_type =
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defaultOr(key_info.GetTagValue(TAG_USER_AUTH_TYPE), HardwareAuthenticatorType::NONE);
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std::vector<uint64_t> key_sids;
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ExtractSids(key_info, &key_sids);
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if (KeyRequiresAuthPerOperation(key_info, purpose))
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return FindAuthPerOpAuthorization(key_sids, auth_type, op_handle);
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else
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return FindTimedAuthorization(key_sids, auth_type, key_info);
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}
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std::tuple<AuthTokenTable::Error, HardwareAuthToken> AuthTokenTable::FindAuthPerOpAuthorization(
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const std::vector<uint64_t>& sids, HardwareAuthenticatorType auth_type, uint64_t op_handle) {
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if (op_handle == 0) return {OP_HANDLE_REQUIRED, {}};
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auto matching_op = find_if(
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entries_, [&](Entry& e) { return e.token().challenge == op_handle && !e.completed(); });
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if (matching_op == entries_.end()) return {AUTH_TOKEN_NOT_FOUND, {}};
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if (!matching_op->SatisfiesAuth(sids, auth_type)) return {AUTH_TOKEN_WRONG_SID, {}};
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return {OK, matching_op->token()};
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}
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std::tuple<AuthTokenTable::Error, HardwareAuthToken>
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AuthTokenTable::FindTimedAuthorization(const std::vector<uint64_t>& sids,
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HardwareAuthenticatorType auth_type,
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const AuthorizationSet& key_info) {
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Entry* newest_match = nullptr;
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for (auto& entry : entries_)
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if (entry.SatisfiesAuth(sids, auth_type) && entry.is_newer_than(newest_match))
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newest_match = &entry;
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if (!newest_match) return {AUTH_TOKEN_NOT_FOUND, {}};
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auto timeout = defaultOr(key_info.GetTagValue(TAG_AUTH_TIMEOUT), 0);
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time_t now = clock_function_();
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if (static_cast<int64_t>(newest_match->time_received()) + timeout < static_cast<int64_t>(now))
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return {AUTH_TOKEN_EXPIRED, {}};
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if (key_info.GetTagValue(TAG_ALLOW_WHILE_ON_BODY).isOk()) {
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if (static_cast<int64_t>(newest_match->time_received()) <
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static_cast<int64_t>(last_off_body_)) {
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return {AUTH_TOKEN_EXPIRED, {}};
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}
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}
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newest_match->UpdateLastUse(now);
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return {OK, newest_match->token()};
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}
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void AuthTokenTable::ExtractSids(const AuthorizationSet& key_info, std::vector<uint64_t>* sids) {
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assert(sids);
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for (auto& param : key_info)
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if (param.tag == Tag::USER_SECURE_ID)
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sids->push_back(authorizationValue(TAG_USER_SECURE_ID, param).value());
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}
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void AuthTokenTable::RemoveEntriesSupersededBy(const Entry& entry) {
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entries_.erase(remove_if(entries_, [&](Entry& e) { return entry.Supersedes(e); }),
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entries_.end());
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}
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void AuthTokenTable::onDeviceOffBody() {
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last_off_body_ = clock_function_();
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}
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void AuthTokenTable::Clear() {
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std::lock_guard<std::mutex> lock(entries_mutex_);
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entries_.clear();
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}
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size_t AuthTokenTable::size() const {
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std::lock_guard<std::mutex> lock(entries_mutex_);
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return entries_.size();
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}
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bool AuthTokenTable::IsSupersededBySomeEntry(const Entry& entry) {
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return std::any_of(entries_.begin(), entries_.end(),
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[&](Entry& e) { return e.Supersedes(entry); });
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}
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void AuthTokenTable::MarkCompleted(const uint64_t op_handle) {
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std::lock_guard<std::mutex> lock(entries_mutex_);
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auto found = find_if(entries_, [&](Entry& e) { return e.token().challenge == op_handle; });
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if (found == entries_.end()) return;
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assert(!IsSupersededBySomeEntry(*found));
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found->mark_completed();
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if (IsSupersededBySomeEntry(*found)) entries_.erase(found);
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}
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AuthTokenTable::Entry::Entry(HardwareAuthToken&& token, time_t current_time)
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: token_(std::move(token)), time_received_(current_time), last_use_(current_time),
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operation_completed_(token_.challenge == 0) {}
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bool AuthTokenTable::Entry::SatisfiesAuth(const std::vector<uint64_t>& sids,
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HardwareAuthenticatorType auth_type) {
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for (auto sid : sids) {
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if (SatisfiesAuth(sid, auth_type)) return true;
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}
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return false;
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}
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void AuthTokenTable::Entry::UpdateLastUse(time_t time) {
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this->last_use_ = time;
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}
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bool AuthTokenTable::Entry::Supersedes(const Entry& entry) const {
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if (!entry.completed()) return false;
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return (token_.userId == entry.token_.userId &&
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token_.authenticatorType == entry.token_.authenticatorType &&
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token_.authenticatorId == entry.token_.authenticatorId && is_newer_than(&entry));
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}
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} // namespace keystore
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