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Shawn Willden489dfe12015-03-17 10:13:27 -06001/*
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 <memory>
Janis Danisevskisff3d7f42018-10-08 07:15:09 -070018#include <mutex>
Shawn Willden489dfe12015-03-17 10:13:27 -060019#include <vector>
20
Shawn Willden0329a822017-12-04 13:55:14 -070021#include <keystore/keymaster_types.h>
Shawn Willden489dfe12015-03-17 10:13:27 -060022
Shawn Willden6507c272016-01-05 22:51:48 -070023#ifndef KEYSTORE_AUTH_TOKEN_TABLE_H_
24#define KEYSTORE_AUTH_TOKEN_TABLE_H_
Shawn Willden489dfe12015-03-17 10:13:27 -060025
Janis Danisevskisc7a9fa22016-10-13 18:43:45 +010026namespace keystore {
27
Shawn Willden489dfe12015-03-17 10:13:27 -060028namespace test {
29class AuthTokenTableTest;
30} // namespace test
31
32time_t clock_gettime_raw();
33
34/**
35 * AuthTokenTable manages a set of received authorization tokens and can provide the appropriate
36 * token for authorizing a key operation.
37 *
38 * To keep the table from growing without bound, superseded entries are removed when possible, and
39 * least recently used entries are automatically pruned when when the table exceeds a size limit,
40 * which is expected to be relatively small, since the implementation uses a linear search.
41 */
42class AuthTokenTable {
43 public:
Chih-Hung Hsiehd7791be2016-07-12 11:58:02 -070044 explicit AuthTokenTable(size_t max_entries = 32, time_t (*clock_function)() = clock_gettime_raw)
Janis Danisevskisc7a9fa22016-10-13 18:43:45 +010045 : max_entries_(max_entries), last_off_body_(clock_function()),
46 clock_function_(clock_function) {}
Shawn Willden489dfe12015-03-17 10:13:27 -060047
48 enum Error {
49 OK,
50 AUTH_NOT_REQUIRED = -1,
51 AUTH_TOKEN_EXPIRED = -2, // Found a matching token, but it's too old.
52 AUTH_TOKEN_WRONG_SID = -3, // Found a token with the right challenge, but wrong SID. This
53 // most likely indicates that the authenticator was updated
54 // (e.g. new fingerprint enrolled).
55 OP_HANDLE_REQUIRED = -4, // The key requires auth per use but op_handle was zero.
56 AUTH_TOKEN_NOT_FOUND = -5,
57 };
58
59 /**
Shawn Willdenbb22a6c2017-12-06 19:35:28 -070060 * Add an authorization token to the table.
Shawn Willden489dfe12015-03-17 10:13:27 -060061 */
Shawn Willden0329a822017-12-04 13:55:14 -070062 void AddAuthenticationToken(HardwareAuthToken&& auth_token);
Shawn Willden489dfe12015-03-17 10:13:27 -060063
64 /**
65 * Find an authorization token that authorizes the operation specified by \p operation_handle on
66 * a key with the characteristics specified in \p key_info.
67 *
68 * This method is O(n * m), where n is the number of KM_TAG_USER_SECURE_ID entries in key_info
69 * and m is the number of entries in the table. It could be made better, but n and m should
70 * always be small.
71 *
72 * The table retains ownership of the returned object.
73 */
Janis Danisevskisff3d7f42018-10-08 07:15:09 -070074 std::tuple<Error, HardwareAuthToken> FindAuthorization(const AuthorizationSet& key_info,
75 KeyPurpose purpose, uint64_t op_handle);
Shawn Willden489dfe12015-03-17 10:13:27 -060076
David Zeuthenab3e5652019-10-28 13:32:48 -040077 std::tuple<Error, HardwareAuthToken>
78 FindAuthorizationForCredstore(uint64_t challenge, uint64_t secureUserId,
79 int64_t authTokenMaxAgeMillis);
80
Shawn Willden489dfe12015-03-17 10:13:27 -060081 /**
Shawn Willden489dfe12015-03-17 10:13:27 -060082 * Mark operation completed. This allows tokens associated with the specified operation to be
83 * superseded by new tokens.
84 */
Janis Danisevskisc7a9fa22016-10-13 18:43:45 +010085 void MarkCompleted(const uint64_t op_handle);
Shawn Willden489dfe12015-03-17 10:13:27 -060086
Tucker Sylvestro0ab28b72016-08-05 18:02:47 -040087 /**
88 * Update the last_off_body_ timestamp so that tokens which remain authorized only so long as
89 * the device stays on body can be revoked.
90 */
91 void onDeviceOffBody();
92
Chad Brubakerbbc76482015-04-16 15:16:44 -070093 void Clear();
94
Janis Danisevskisff3d7f42018-10-08 07:15:09 -070095 /**
96 * This function shall only be used for testing.
97 *
98 * BEWARE: Since the auth token table can be accessed
99 * concurrently, the size may be out dated as soon as it returns.
100 */
101 size_t size() const;
Shawn Willden489dfe12015-03-17 10:13:27 -0600102
103 private:
104 friend class AuthTokenTableTest;
105
106 class Entry {
107 public:
Shawn Willden0329a822017-12-04 13:55:14 -0700108 Entry(HardwareAuthToken&& token, time_t current_time);
Chih-Hung Hsiehf73b1982018-09-25 12:03:21 -0700109 Entry(Entry&& entry) noexcept { *this = std::move(entry); }
Shawn Willden489dfe12015-03-17 10:13:27 -0600110
Chih-Hung Hsiehf73b1982018-09-25 12:03:21 -0700111 void operator=(Entry&& rhs) noexcept {
Shawn Willden489dfe12015-03-17 10:13:27 -0600112 token_ = std::move(rhs.token_);
113 time_received_ = rhs.time_received_;
114 last_use_ = rhs.last_use_;
115 operation_completed_ = rhs.operation_completed_;
116 }
117
118 bool operator<(const Entry& rhs) const { return last_use_ < rhs.last_use_; }
119
120 void UpdateLastUse(time_t time);
121
122 bool Supersedes(const Entry& entry) const;
Janis Danisevskisc7a9fa22016-10-13 18:43:45 +0100123 bool SatisfiesAuth(const std::vector<uint64_t>& sids, HardwareAuthenticatorType auth_type);
Shawn Willden489dfe12015-03-17 10:13:27 -0600124
Rubin Xubfb01d92017-10-23 17:04:25 +0100125 bool is_newer_than(const Entry* entry) const {
Janis Danisevskisc7a9fa22016-10-13 18:43:45 +0100126 if (!entry) return true;
Shawn Willden0329a822017-12-04 13:55:14 -0700127 uint64_t ts = token_.timestamp;
128 uint64_t other_ts = entry->token_.timestamp;
Rubin Xubfb01d92017-10-23 17:04:25 +0100129 // Normally comparing timestamp_host_order alone is sufficient, but here is an
130 // additional hack to compare time_received value for some devices where their auth
131 // tokens contain fixed timestamp (due to the a stuck secure RTC on them)
132 return (ts > other_ts) ||
133 ((ts == other_ts) && (time_received_ > entry->time_received_));
Shawn Willden489dfe12015-03-17 10:13:27 -0600134 }
135
136 void mark_completed() { operation_completed_ = true; }
137
Shawn Willden0329a822017-12-04 13:55:14 -0700138 const HardwareAuthToken& token() const & { return token_; }
Shawn Willden489dfe12015-03-17 10:13:27 -0600139 time_t time_received() const { return time_received_; }
140 bool completed() const { return operation_completed_; }
Shawn Willden489dfe12015-03-17 10:13:27 -0600141
142 private:
Shawn Willden0329a822017-12-04 13:55:14 -0700143 bool SatisfiesAuth(uint64_t sid, HardwareAuthenticatorType auth_type) const {
144 return (sid == token_.userId || sid == token_.authenticatorId) &&
145 (auth_type & token_.authenticatorType) != 0;
146 }
147
148 HardwareAuthToken token_;
Shawn Willden489dfe12015-03-17 10:13:27 -0600149 time_t time_received_;
150 time_t last_use_;
151 bool operation_completed_;
152 };
153
Janis Danisevskisff3d7f42018-10-08 07:15:09 -0700154 std::tuple<Error, HardwareAuthToken>
155 FindAuthPerOpAuthorization(const std::vector<uint64_t>& sids,
156 HardwareAuthenticatorType auth_type, uint64_t op_handle);
157 std::tuple<Error, HardwareAuthToken> FindTimedAuthorization(const std::vector<uint64_t>& sids,
158 HardwareAuthenticatorType auth_type,
159 const AuthorizationSet& key_info);
Shawn Willden489dfe12015-03-17 10:13:27 -0600160 void ExtractSids(const AuthorizationSet& key_info, std::vector<uint64_t>* sids);
161 void RemoveEntriesSupersededBy(const Entry& entry);
162 bool IsSupersededBySomeEntry(const Entry& entry);
163
Janis Danisevskisff3d7f42018-10-08 07:15:09 -0700164 /**
165 * Guards the entries_ vector against concurrent modification. All public facing methods
166 * reading of modifying the vector must grab this mutex.
167 */
168 mutable std::mutex entries_mutex_;
Shawn Willden489dfe12015-03-17 10:13:27 -0600169 std::vector<Entry> entries_;
170 size_t max_entries_;
Tucker Sylvestro0ab28b72016-08-05 18:02:47 -0400171 time_t last_off_body_;
Shawn Willden489dfe12015-03-17 10:13:27 -0600172 time_t (*clock_function_)();
173};
174
Shawn Willden0329a822017-12-04 13:55:14 -0700175} // namespace keystore
Shawn Willden489dfe12015-03-17 10:13:27 -0600176
Shawn Willden6507c272016-01-05 22:51:48 -0700177#endif // KEYSTORE_AUTH_TOKEN_TABLE_H_