Shawn Willden | 489dfe1 | 2015-03-17 10:13:27 -0600 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2015 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #include "auth_token_table.h" |
| 18 | |
| 19 | #include <assert.h> |
| 20 | #include <time.h> |
| 21 | |
| 22 | #include <algorithm> |
| 23 | |
Shawn Willden | 0bdad21 | 2015-05-18 21:08:39 -0600 | [diff] [blame] | 24 | #include <keymaster/android_keymaster_utils.h> |
Shawn Willden | 489dfe1 | 2015-03-17 10:13:27 -0600 | [diff] [blame] | 25 | #include <keymaster/logger.h> |
| 26 | |
| 27 | namespace keymaster { |
| 28 | |
| 29 | // |
| 30 | // Some trivial template wrappers around std algorithms, so they take containers not ranges. |
| 31 | // |
| 32 | template <typename Container, typename Predicate> |
| 33 | typename Container::iterator find_if(Container& container, Predicate pred) { |
| 34 | return std::find_if(container.begin(), container.end(), pred); |
| 35 | } |
| 36 | |
| 37 | template <typename Container, typename Predicate> |
| 38 | typename Container::iterator remove_if(Container& container, Predicate pred) { |
| 39 | return std::remove_if(container.begin(), container.end(), pred); |
| 40 | } |
| 41 | |
| 42 | template <typename Container> typename Container::iterator min_element(Container& container) { |
| 43 | return std::min_element(container.begin(), container.end()); |
| 44 | } |
| 45 | |
| 46 | time_t clock_gettime_raw() { |
| 47 | struct timespec time; |
| 48 | clock_gettime(CLOCK_MONOTONIC_RAW, &time); |
| 49 | return time.tv_sec; |
| 50 | } |
| 51 | |
| 52 | void AuthTokenTable::AddAuthenticationToken(const hw_auth_token_t* auth_token) { |
| 53 | Entry new_entry(auth_token, clock_function_()); |
| 54 | RemoveEntriesSupersededBy(new_entry); |
| 55 | if (entries_.size() >= max_entries_) { |
| 56 | LOG_W("Auth token table filled up; replacing oldest entry", 0); |
| 57 | *min_element(entries_) = std::move(new_entry); |
| 58 | } else { |
| 59 | entries_.push_back(std::move(new_entry)); |
| 60 | } |
| 61 | } |
| 62 | |
Shawn Willden | b2ffa42 | 2015-06-17 12:18:55 -0600 | [diff] [blame^] | 63 | inline bool is_secret_key_operation(keymaster_algorithm_t algorithm, keymaster_purpose_t purpose) { |
| 64 | if ((algorithm != KM_ALGORITHM_RSA || algorithm != KM_ALGORITHM_EC)) |
| 65 | return true; |
| 66 | if (purpose == KM_PURPOSE_SIGN || purpose == KM_PURPOSE_DECRYPT) |
| 67 | return true; |
| 68 | return false; |
Shawn Willden | 489dfe1 | 2015-03-17 10:13:27 -0600 | [diff] [blame] | 69 | } |
| 70 | |
Shawn Willden | b2ffa42 | 2015-06-17 12:18:55 -0600 | [diff] [blame^] | 71 | inline bool KeyRequiresAuthentication(const AuthorizationSet& key_info, |
| 72 | keymaster_purpose_t purpose) { |
| 73 | keymaster_algorithm_t algorithm = KM_ALGORITHM_AES; |
| 74 | key_info.GetTagValue(TAG_ALGORITHM, &algorithm); |
| 75 | return is_secret_key_operation(algorithm, purpose) && key_info.find(TAG_NO_AUTH_REQUIRED) == -1; |
| 76 | } |
| 77 | |
| 78 | inline bool KeyRequiresAuthPerOperation(const AuthorizationSet& key_info, |
| 79 | keymaster_purpose_t purpose) { |
| 80 | keymaster_algorithm_t algorithm = KM_ALGORITHM_AES; |
| 81 | key_info.GetTagValue(TAG_ALGORITHM, &algorithm); |
| 82 | return is_secret_key_operation(algorithm, purpose) && key_info.find(TAG_AUTH_TIMEOUT) == -1; |
Shawn Willden | 489dfe1 | 2015-03-17 10:13:27 -0600 | [diff] [blame] | 83 | } |
| 84 | |
| 85 | AuthTokenTable::Error AuthTokenTable::FindAuthorization(const AuthorizationSet& key_info, |
Shawn Willden | b2ffa42 | 2015-06-17 12:18:55 -0600 | [diff] [blame^] | 86 | keymaster_purpose_t purpose, |
Shawn Willden | 489dfe1 | 2015-03-17 10:13:27 -0600 | [diff] [blame] | 87 | keymaster_operation_handle_t op_handle, |
| 88 | const hw_auth_token_t** found) { |
Shawn Willden | b2ffa42 | 2015-06-17 12:18:55 -0600 | [diff] [blame^] | 89 | if (!KeyRequiresAuthentication(key_info, purpose)) |
Shawn Willden | 489dfe1 | 2015-03-17 10:13:27 -0600 | [diff] [blame] | 90 | return AUTH_NOT_REQUIRED; |
| 91 | |
| 92 | hw_authenticator_type_t auth_type = HW_AUTH_NONE; |
| 93 | key_info.GetTagValue(TAG_USER_AUTH_TYPE, &auth_type); |
| 94 | |
| 95 | std::vector<uint64_t> key_sids; |
| 96 | ExtractSids(key_info, &key_sids); |
| 97 | |
Shawn Willden | b2ffa42 | 2015-06-17 12:18:55 -0600 | [diff] [blame^] | 98 | if (KeyRequiresAuthPerOperation(key_info, purpose)) |
Shawn Willden | 489dfe1 | 2015-03-17 10:13:27 -0600 | [diff] [blame] | 99 | return FindAuthPerOpAuthorization(key_sids, auth_type, op_handle, found); |
| 100 | else |
| 101 | return FindTimedAuthorization(key_sids, auth_type, key_info, found); |
| 102 | } |
| 103 | |
| 104 | AuthTokenTable::Error AuthTokenTable::FindAuthPerOpAuthorization( |
| 105 | const std::vector<uint64_t>& sids, hw_authenticator_type_t auth_type, |
| 106 | keymaster_operation_handle_t op_handle, const hw_auth_token_t** found) { |
| 107 | if (op_handle == 0) |
| 108 | return OP_HANDLE_REQUIRED; |
| 109 | |
| 110 | auto matching_op = find_if( |
| 111 | entries_, [&](Entry& e) { return e.token()->challenge == op_handle && !e.completed(); }); |
| 112 | |
| 113 | if (matching_op == entries_.end()) |
| 114 | return AUTH_TOKEN_NOT_FOUND; |
| 115 | |
| 116 | if (!matching_op->SatisfiesAuth(sids, auth_type)) |
| 117 | return AUTH_TOKEN_WRONG_SID; |
| 118 | |
| 119 | *found = matching_op->token(); |
| 120 | return OK; |
| 121 | } |
| 122 | |
| 123 | AuthTokenTable::Error AuthTokenTable::FindTimedAuthorization(const std::vector<uint64_t>& sids, |
| 124 | hw_authenticator_type_t auth_type, |
| 125 | const AuthorizationSet& key_info, |
| 126 | const hw_auth_token_t** found) { |
| 127 | Entry* newest_match = NULL; |
| 128 | for (auto& entry : entries_) |
| 129 | if (entry.SatisfiesAuth(sids, auth_type) && entry.is_newer_than(newest_match)) |
| 130 | newest_match = &entry; |
| 131 | |
| 132 | if (!newest_match) |
| 133 | return AUTH_TOKEN_NOT_FOUND; |
| 134 | |
| 135 | uint32_t timeout; |
| 136 | key_info.GetTagValue(TAG_AUTH_TIMEOUT, &timeout); |
| 137 | time_t now = clock_function_(); |
| 138 | if (static_cast<int64_t>(newest_match->time_received()) + timeout < static_cast<int64_t>(now)) |
| 139 | return AUTH_TOKEN_EXPIRED; |
| 140 | |
| 141 | newest_match->UpdateLastUse(now); |
| 142 | *found = newest_match->token(); |
| 143 | return OK; |
| 144 | } |
| 145 | |
| 146 | void AuthTokenTable::ExtractSids(const AuthorizationSet& key_info, std::vector<uint64_t>* sids) { |
| 147 | assert(sids); |
| 148 | for (auto& param : key_info) |
| 149 | if (param.tag == TAG_USER_SECURE_ID) |
| 150 | sids->push_back(param.long_integer); |
| 151 | } |
| 152 | |
| 153 | void AuthTokenTable::RemoveEntriesSupersededBy(const Entry& entry) { |
| 154 | entries_.erase(remove_if(entries_, [&](Entry& e) { return entry.Supersedes(e); }), |
| 155 | entries_.end()); |
| 156 | } |
| 157 | |
Chad Brubaker | bbc7648 | 2015-04-16 15:16:44 -0700 | [diff] [blame] | 158 | void AuthTokenTable::Clear() { |
| 159 | entries_.clear(); |
| 160 | } |
| 161 | |
Shawn Willden | 489dfe1 | 2015-03-17 10:13:27 -0600 | [diff] [blame] | 162 | bool AuthTokenTable::IsSupersededBySomeEntry(const Entry& entry) { |
| 163 | return std::any_of(entries_.begin(), entries_.end(), |
| 164 | [&](Entry& e) { return e.Supersedes(entry); }); |
| 165 | } |
| 166 | |
| 167 | void AuthTokenTable::MarkCompleted(const keymaster_operation_handle_t op_handle) { |
| 168 | auto found = find_if(entries_, [&](Entry& e) { return e.token()->challenge == op_handle; }); |
| 169 | if (found == entries_.end()) |
| 170 | return; |
| 171 | |
| 172 | assert(!IsSupersededBySomeEntry(*found)); |
| 173 | found->mark_completed(); |
| 174 | |
| 175 | if (IsSupersededBySomeEntry(*found)) |
| 176 | entries_.erase(found); |
| 177 | } |
| 178 | |
| 179 | AuthTokenTable::Entry::Entry(const hw_auth_token_t* token, time_t current_time) |
| 180 | : token_(token), time_received_(current_time), last_use_(current_time), |
| 181 | operation_completed_(token_->challenge == 0) { |
| 182 | } |
| 183 | |
| 184 | uint32_t AuthTokenTable::Entry::timestamp_host_order() const { |
| 185 | return ntoh(token_->timestamp); |
| 186 | } |
| 187 | |
| 188 | hw_authenticator_type_t AuthTokenTable::Entry::authenticator_type() const { |
| 189 | hw_authenticator_type_t result = static_cast<hw_authenticator_type_t>( |
| 190 | ntoh(static_cast<uint32_t>(token_->authenticator_type))); |
| 191 | return result; |
| 192 | } |
| 193 | |
| 194 | bool AuthTokenTable::Entry::SatisfiesAuth(const std::vector<uint64_t>& sids, |
| 195 | hw_authenticator_type_t auth_type) { |
| 196 | for (auto sid : sids) |
| 197 | if ((sid == token_->authenticator_id) || |
| 198 | (sid == token_->user_id && (auth_type & authenticator_type()) != 0)) |
| 199 | return true; |
| 200 | return false; |
| 201 | } |
| 202 | |
| 203 | void AuthTokenTable::Entry::UpdateLastUse(time_t time) { |
| 204 | this->last_use_ = time; |
| 205 | } |
| 206 | |
| 207 | bool AuthTokenTable::Entry::Supersedes(const Entry& entry) const { |
| 208 | if (!entry.completed()) |
| 209 | return false; |
| 210 | |
| 211 | return (token_->user_id == entry.token_->user_id && |
| 212 | token_->authenticator_type == entry.token_->authenticator_type && |
| 213 | token_->authenticator_type == entry.token_->authenticator_type && |
| 214 | timestamp_host_order() > entry.timestamp_host_order()); |
| 215 | } |
| 216 | |
| 217 | } // namespace keymaster |