1 // Copyright 2015 The Android Open Source Project 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef KEYSTORE_KEYSTORE_CLIENT_H_ 16 #define KEYSTORE_KEYSTORE_CLIENT_H_ 17 18 #include <set> 19 #include <string> 20 #include <vector> 21 22 #include "authorization_set.h" 23 #include "keystore.h" 24 #include "keystore_return_types.h" 25 26 namespace keystore { 27 28 29 30 // An abstract class providing a convenient interface to keystore services. This 31 // interface is designed to: 32 // - hide details of the IPC mechanism (e.g. binder) 33 // - use std data types 34 // - encourage the use of keystore::AuthorizationSet[Builder] 35 // - be convenient for native services integrating with keystore 36 // - be safely mocked for unit testing (e.g. pure virtual methods) 37 // 38 // Example usage: 39 // KeystoreClient* keystore = new KeyStoreClientImpl(); 40 // keystore->AddRandomNumberGeneratorEntropy("unpredictable"); 41 // 42 // Notes on error codes: 43 // Keystore binder methods return a variety of values including ResponseCode 44 // values defined in keystore.h, keymaster_error_t values defined in 45 // keymaster_defs.h, or just 0 or -1 (both of which conflict with 46 // keymaster_error_t). The methods in this class converge on a single success 47 // indicator for convenience. KM_ERROR_OK was chosen over ::NO_ERROR for two 48 // reasons: 49 // 1) KM_ERROR_OK is 0, which is a common convention for success, is the gmock 50 // default, and allows error checks like 'if (error) {...'. 51 // 2) Although both pollute the global namespace, KM_ERROR_OK has a prefix per 52 // C convention and hopefully clients can use this interface without 53 // needing to include 'keystore.h' directly. 54 class KeystoreClient { 55 public: 56 KeystoreClient() = default; 57 virtual ~KeystoreClient() = default; 58 59 // Encrypts and authenticates |data| with minimal configuration for local 60 // decryption. If a key identified by |key_name| does not already exist it 61 // will be generated. On success returns true and populates |encrypted_data|. 62 // Note: implementations may generate more than one key but they will always 63 // have |key_name| as a prefix. 64 virtual bool encryptWithAuthentication(const std::string& key_name, const std::string& data, 65 std::string* encrypted_data) = 0; 66 67 // Decrypts and authenticates |encrypted_data| as output by 68 // EncryptWithAuthentication using the key(s) identified by |key_name|. On 69 // success returns true and populates |data|. 70 virtual bool decryptWithAuthentication(const std::string& key_name, 71 const std::string& encrypted_data, 72 std::string* data) = 0; 73 74 // Performs a Begin/Update/Finish sequence for an operation. The |purpose|, 75 // |key_name|, |input_parameters|, and |output_parameters| are as in 76 // BeginOperation. The |input_data| is as in UpdateOperation. The 77 // |signature_to_verify| and |output_data| are as in FinishOperation. On 78 // success returns true. 79 virtual bool oneShotOperation(KeyPurpose purpose, const std::string& key_name, 80 const keystore::AuthorizationSet& input_parameters, 81 const std::string& input_data, 82 const std::string& signature_to_verify, 83 keystore::AuthorizationSet* output_parameters, 84 std::string* output_data) = 0; 85 86 // Adds |entropy| to the random number generator. Returns KM_ERROR_OK on 87 // success and a Keystore ResponseCode or keymaster_error_t on failure. 88 virtual KeyStoreNativeReturnCode addRandomNumberGeneratorEntropy(const std::string& entropy) = 0; 89 90 // Generates a key according to the given |key_parameters| and stores it with 91 // the given |key_name|. The [hardware|software]_enforced_characteristics of 92 // the key are provided on success. Returns KM_ERROR_OK on success. Returns 93 // KM_ERROR_OK on success and a Keystore ResponseCode or keymaster_error_t on 94 // failure. 95 virtual KeyStoreNativeReturnCode generateKey(const std::string& key_name, 96 const keystore::AuthorizationSet& key_parameters, 97 keystore::AuthorizationSet* hardware_enforced_characteristics, 98 keystore::AuthorizationSet* software_enforced_characteristics) = 0; 99 100 // Provides the [hardware|software]_enforced_characteristics of a key 101 // identified by |key_name|. Returns KM_ERROR_OK on success and a Keystore 102 // ResponseCode or keymaster_error_t on failure. 103 virtual KeyStoreNativeReturnCode 104 getKeyCharacteristics(const std::string& key_name, 105 keystore::AuthorizationSet* hardware_enforced_characteristics, 106 keystore::AuthorizationSet* software_enforced_characteristics) = 0; 107 108 // Imports |key_data| in the given |key_format|, applies the given 109 // |key_parameters|, and stores it with the given |key_name|. The 110 // [hardware|software]_enforced_characteristics of the key are provided on 111 // success. Returns KM_ERROR_OK on success and a Keystore ResponseCode or 112 // keymaster_error_t on failure. 113 virtual KeyStoreNativeReturnCode importKey(const std::string& key_name, 114 const keystore::AuthorizationSet& key_parameters, 115 KeyFormat key_format, const std::string& key_data, 116 keystore::AuthorizationSet* hardware_enforced_characteristics, 117 keystore::AuthorizationSet* software_enforced_characteristics) = 0; 118 119 // Exports the public key identified by |key_name| to |export_data| using 120 // |export_format|. Returns KM_ERROR_OK on success and a Keystore ResponseCode 121 // or keymaster_error_t on failure. 122 virtual KeyStoreNativeReturnCode exportKey(KeyFormat export_format, const std::string& key_name, 123 std::string* export_data) = 0; 124 125 // Deletes the key identified by |key_name|. Returns KM_ERROR_OK on success 126 // and a Keystore ResponseCode or keymaster_error_t on failure. 127 virtual KeyStoreNativeReturnCode deleteKey(const std::string& key_name) = 0; 128 129 // Deletes all keys owned by the caller. Returns KM_ERROR_OK on success and a 130 // Keystore ResponseCode or keymaster_error_t on failure. 131 virtual KeyStoreNativeReturnCode deleteAllKeys() = 0; 132 133 // Begins a cryptographic operation (e.g. encrypt, sign) identified by 134 // |purpose| using the key identified by |key_name| and the given 135 // |input_parameters|. On success, any |output_parameters| and an operation 136 // |handle| are populated. Returns KM_ERROR_OK on success and a Keystore 137 // ResponseCode or keymaster_error_t on failure. 138 virtual KeyStoreNativeReturnCode beginOperation(KeyPurpose purpose, const std::string& key_name, 139 const keystore::AuthorizationSet& input_parameters, 140 keystore::AuthorizationSet* output_parameters, 141 uint64_t* handle) = 0; 142 143 // Continues the operation associated with |handle| using the given 144 // |input_parameters| and |input_data|. On success, the 145 // |num_input_bytes_consumed| and any |output_parameters| are populated. Any 146 // |output_data| will be appended. Returns KM_ERROR_OK on success and a 147 // Keystore ResponseCode or keymaster_error_t on failure. 148 virtual KeyStoreNativeReturnCode updateOperation(uint64_t handle, 149 const keystore::AuthorizationSet& input_parameters, 150 const std::string& input_data, size_t* num_input_bytes_consumed, 151 keystore::AuthorizationSet* output_parameters, 152 std::string* output_data) = 0; 153 154 // Finishes the operation associated with |handle| using the given 155 // |input_parameters| and, if necessary, a |signature_to_verify|. On success, 156 // any |output_parameters| are populated and |output_data| is appended. 157 // Returns KM_ERROR_OK on success and a Keystore ResponseCode or 158 // keymaster_error_t on failure. 159 virtual KeyStoreNativeReturnCode finishOperation(uint64_t handle, 160 const keystore::AuthorizationSet& input_parameters, 161 const std::string& signature_to_verify, 162 keystore::AuthorizationSet* output_parameters, 163 std::string* output_data) = 0; 164 165 // Aborts the operation associated with |handle|. Returns KM_ERROR_OK on 166 // success and a Keystore ResponseCode or keymaster_error_t on failure. 167 virtual KeyStoreNativeReturnCode abortOperation(uint64_t handle) = 0; 168 169 // Returns true if a key identified by |key_name| exists in the caller's 170 // key store. Returns false if an error occurs. 171 virtual bool doesKeyExist(const std::string& key_name) = 0; 172 173 // Provides a |key_name_list| containing all existing key names in the 174 // caller's key store starting with |prefix|. Returns true on success. 175 virtual bool listKeys(const std::string& prefix, std::vector<std::string>* key_name_list) = 0; 176 177 private: 178 DISALLOW_COPY_AND_ASSIGN(KeystoreClient); 179 }; 180 181 } // namespace keystore 182 183 #endif // KEYSTORE_KEYSTORE_CLIENT_H_ 184
