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 <memory> 18 #include <vector> 19 20 #include <hardware/hw_auth_token.h> 21 #include <keymaster/authorization_set.h> 22 23 #ifndef SYSTEM_KEYMASTER_AUTH_TOKEN_TABLE_H 24 #define SYSTEM_KEYMASTER_AUTH_TOKEN_TABLE_H 25 26 namespace keymaster { 27 28 namespace test { 29 class AuthTokenTableTest; 30 } // namespace test 31 32 time_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the appropriate 36 * token for authorizing a key operation. 37 * 38 * To keep the table from growing without bound, superseded entries are removed when possible, and 39 * least recently used entries are automatically pruned when when the table exceeds a size limit, 40 * which is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 */ 42 class AuthTokenTable { 43 public: 44 AuthTokenTable(size_t max_entries = 32, time_t (*clock_function)() = clock_gettime_raw) 45 : max_entries_(max_entries), clock_function_(clock_function) {} 46 47 enum Error { 48 OK, 49 AUTH_NOT_REQUIRED = -1, 50 AUTH_TOKEN_EXPIRED = -2, // Found a matching token, but it's too old. 51 AUTH_TOKEN_WRONG_SID = -3, // Found a token with the right challenge, but wrong SID. This 52 // most likely indicates that the authenticator was updated 53 // (e.g. new fingerprint enrolled). 54 OP_HANDLE_REQUIRED = -4, // The key requires auth per use but op_handle was zero. 55 AUTH_TOKEN_NOT_FOUND = -5, 56 }; 57 58 /** 59 * Add an authorization token to the table. The table takes ownership of the argument. 60 */ 61 void AddAuthenticationToken(const hw_auth_token_t* token); 62 63 /** 64 * Find an authorization token that authorizes the operation specified by \p operation_handle on 65 * a key with the characteristics specified in \p key_info. 66 * 67 * This method is O(n * m), where n is the number of KM_TAG_USER_SECURE_ID entries in key_info 68 * and m is the number of entries in the table. It could be made better, but n and m should 69 * always be small. 70 * 71 * The table retains ownership of the returned object. 72 */ 73 Error FindAuthorization(const AuthorizationSet& key_info, keymaster_purpose_t purpose, 74 keymaster_operation_handle_t op_handle, const hw_auth_token_t** found); 75 76 /** 77 * Find an authorization token that authorizes the operation specified by \p operation_handle on 78 * a key with the characteristics specified in \p key_info. 79 * 80 * This method is O(n * m), where n is the number of KM_TAG_USER_SECURE_ID entries in key_info 81 * and m is the number of entries in the table. It could be made better, but n and m should 82 * always be small. 83 * 84 * The table retains ownership of the returned object. 85 */ 86 Error FindAuthorization(const keymaster_key_param_t* params, size_t params_count, 87 keymaster_purpose_t purpose, keymaster_operation_handle_t op_handle, 88 const hw_auth_token_t** found) { 89 return FindAuthorization(AuthorizationSet(params, params_count), purpose, op_handle, found); 90 } 91 92 /** 93 * Mark operation completed. This allows tokens associated with the specified operation to be 94 * superseded by new tokens. 95 */ 96 void MarkCompleted(const keymaster_operation_handle_t op_handle); 97 98 void Clear(); 99 100 size_t size() { return entries_.size(); } 101 102 private: 103 friend class AuthTokenTableTest; 104 105 class Entry { 106 public: 107 Entry(const hw_auth_token_t* token, time_t current_time); 108 Entry(Entry&& entry) { *this = std::move(entry); } 109 110 void operator=(Entry&& rhs) { 111 token_ = std::move(rhs.token_); 112 time_received_ = rhs.time_received_; 113 last_use_ = rhs.last_use_; 114 operation_completed_ = rhs.operation_completed_; 115 } 116 117 bool operator<(const Entry& rhs) const { return last_use_ < rhs.last_use_; } 118 119 void UpdateLastUse(time_t time); 120 121 bool Supersedes(const Entry& entry) const; 122 bool SatisfiesAuth(const std::vector<uint64_t>& sids, hw_authenticator_type_t auth_type); 123 124 bool is_newer_than(const Entry* entry) { 125 if (!entry) 126 return true; 127 return timestamp_host_order() > entry->timestamp_host_order(); 128 } 129 130 void mark_completed() { operation_completed_ = true; } 131 132 const hw_auth_token_t* token() { return token_.get(); } 133 time_t time_received() const { return time_received_; } 134 bool completed() const { return operation_completed_; } 135 uint32_t timestamp_host_order() const; 136 hw_authenticator_type_t authenticator_type() const; 137 138 private: 139 std::unique_ptr<const hw_auth_token_t> token_; 140 time_t time_received_; 141 time_t last_use_; 142 bool operation_completed_; 143 }; 144 145 Error FindAuthPerOpAuthorization(const std::vector<uint64_t>& sids, 146 hw_authenticator_type_t auth_type, 147 keymaster_operation_handle_t op_handle, 148 const hw_auth_token_t** found); 149 Error FindTimedAuthorization(const std::vector<uint64_t>& sids, 150 hw_authenticator_type_t auth_type, 151 const AuthorizationSet& key_info, const hw_auth_token_t** found); 152 void ExtractSids(const AuthorizationSet& key_info, std::vector<uint64_t>* sids); 153 void RemoveEntriesSupersededBy(const Entry& entry); 154 bool IsSupersededBySomeEntry(const Entry& entry); 155 156 std::vector<Entry> entries_; 157 size_t max_entries_; 158 time_t (*clock_function_)(); 159 }; 160 161 } // namespace keymaster 162 163 #endif // SYSTEM_KEYMASTER_AUTH_TOKEN_TABLE_H 164
