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 <memory> 19 #include <optional> 20 #include <set> 21 #include <string> 22 #include <vector> 23 24 #include <android-base/macros.h> 25 26 #include "keymaster_types.h" 27 #include "keystore.h" 28 #include "keystore_return_types.h" 29 30 namespace keystore { 31 32 // An abstract class providing a convenient interface to keystore services. This 33 // interface is designed to: 34 // - hide details of the IPC mechanism (e.g. binder) 35 // - use std data types 36 // - encourage the use of keystore::AuthorizationSet[Builder] 37 // - be convenient for native services integrating with keystore 38 // - be safely mocked for unit testing (e.g. pure virtual methods) 39 // 40 // Example usage: 41 // KeystoreClient* keystore = new KeyStoreClientImpl(); 42 // keystore->AddRandomNumberGeneratorEntropy("unpredictable"); 43 // 44 // Notes on error codes: 45 // Keystore binder methods return a variety of values including ResponseCode 46 // values defined in keystore.h, keymaster_error_t values defined in 47 // keymaster_defs.h, or just 0 or -1 (both of which conflict with 48 // keymaster_error_t). The methods in this class converge on a single success 49 // indicator for convenience. KM_ERROR_OK was chosen over ::NO_ERROR for two 50 // reasons: 51 // 1) KM_ERROR_OK is 0, which is a common convention for success, is the gmock 52 // default, and allows error checks like 'if (error) {...'. 53 // 2) Although both pollute the global namespace, KM_ERROR_OK has a prefix per 54 // C convention and hopefully clients can use this interface without 55 // needing to include 'keystore.h' directly. 56 class KeystoreClient { 57 public: 58 KeystoreClient() = default; 59 virtual ~KeystoreClient() = default; 60 61 // Encrypts and authenticates |data| with minimal configuration for local 62 // decryption. If a key identified by |key_name| does not already exist it 63 // will be generated. On success returns true and populates |encrypted_data|. 64 // Note: implementations may generate more than one key but they will always 65 // have |key_name| as a prefix. 66 virtual bool encryptWithAuthentication(const std::string& key_name, const std::string& data, 67 int32_t flags, std::string* encrypted_data) = 0; 68 69 // Decrypts and authenticates |encrypted_data| as output by 70 // EncryptWithAuthentication using the key(s) identified by |key_name|. On 71 // success returns true and populates |data|. 72 virtual bool decryptWithAuthentication(const std::string& key_name, 73 const std::string& encrypted_data, 74 std::string* data) = 0; 75 76 // Performs a Begin/Update/Finish sequence for an operation. The |purpose|, 77 // |key_name|, |input_parameters|, and |output_parameters| are as in 78 // BeginOperation. The |input_data| is as in UpdateOperation. The 79 // |signature_to_verify| and |output_data| are as in FinishOperation. On 80 // success returns true. 81 virtual bool oneShotOperation(KeyPurpose purpose, const std::string& key_name, 82 const keystore::AuthorizationSet& input_parameters, 83 const std::string& input_data, 84 const std::string& signature_to_verify, 85 keystore::AuthorizationSet* output_parameters, 86 std::string* output_data) = 0; 87 88 // Adds |entropy| to the random number generator. Returns KM_ERROR_OK on 89 // success and a Keystore ResponseCode or keymaster_error_t on failure. 90 virtual KeyStoreNativeReturnCode addRandomNumberGeneratorEntropy(const std::string& entropy, 91 int32_t flags) = 0; 92 93 // Generates a key according to the given |key_parameters| and stores it with 94 // the given |key_name|. The [hardware|software]_enforced_characteristics of 95 // the key are provided on success. Returns KM_ERROR_OK on success. Returns 96 // KM_ERROR_OK on success and a Keystore ResponseCode or keymaster_error_t on 97 // failure. 98 virtual KeyStoreNativeReturnCode 99 generateKey(const std::string& key_name, const keystore::AuthorizationSet& key_parameters, 100 int32_t flags, keystore::AuthorizationSet* hardware_enforced_characteristics, 101 keystore::AuthorizationSet* software_enforced_characteristics) = 0; 102 103 // Provides the [hardware|software]_enforced_characteristics of a key 104 // identified by |key_name|. Returns KM_ERROR_OK on success and a Keystore 105 // ResponseCode or keymaster_error_t on failure. 106 virtual KeyStoreNativeReturnCode 107 getKeyCharacteristics(const std::string& key_name, 108 keystore::AuthorizationSet* hardware_enforced_characteristics, 109 keystore::AuthorizationSet* software_enforced_characteristics) = 0; 110 111 // Imports |key_data| in the given |key_format|, applies the given 112 // |key_parameters|, and stores it with the given |key_name|. The 113 // [hardware|software]_enforced_characteristics of the key are provided on 114 // success. Returns KM_ERROR_OK on success and a Keystore ResponseCode or 115 // keymaster_error_t on failure. 116 virtual KeyStoreNativeReturnCode 117 importKey(const std::string& key_name, const keystore::AuthorizationSet& key_parameters, 118 KeyFormat key_format, const std::string& key_data, 119 keystore::AuthorizationSet* hardware_enforced_characteristics, 120 keystore::AuthorizationSet* software_enforced_characteristics) = 0; 121 122 // Exports the public key identified by |key_name| to |export_data| using 123 // |export_format|. Returns KM_ERROR_OK on success and a Keystore ResponseCode 124 // or keymaster_error_t on failure. 125 virtual KeyStoreNativeReturnCode exportKey(KeyFormat export_format, const std::string& key_name, 126 std::string* export_data) = 0; 127 128 // Deletes the key identified by |key_name|. Returns KM_ERROR_OK on success 129 // and a Keystore ResponseCode or keymaster_error_t on failure. 130 virtual KeyStoreNativeReturnCode deleteKey(const std::string& key_name) = 0; 131 132 // Deletes all keys owned by the caller. Returns KM_ERROR_OK on success and a 133 // Keystore ResponseCode or keymaster_error_t on failure. 134 virtual KeyStoreNativeReturnCode deleteAllKeys() = 0; 135 136 // Begins a cryptographic operation (e.g. encrypt, sign) identified by 137 // |purpose| using the key identified by |key_name| and the given 138 // |input_parameters|. On success, any |output_parameters| and an operation 139 // |handle| are populated. Returns KM_ERROR_OK on success and a Keystore 140 // ResponseCode or keymaster_error_t on failure. 141 virtual KeyStoreNativeReturnCode 142 beginOperation(KeyPurpose purpose, const std::string& key_name, 143 const keystore::AuthorizationSet& input_parameters, 144 keystore::AuthorizationSet* output_parameters, uint64_t* handle) = 0; 145 146 // Continues the operation associated with |handle| using the given 147 // |input_parameters| and |input_data|. On success, the 148 // |num_input_bytes_consumed| and any |output_parameters| are populated. Any 149 // |output_data| will be appended. Returns KM_ERROR_OK on success and a 150 // Keystore ResponseCode or keymaster_error_t on failure. 151 virtual KeyStoreNativeReturnCode 152 updateOperation(uint64_t handle, const keystore::AuthorizationSet& input_parameters, 153 const std::string& input_data, size_t* num_input_bytes_consumed, 154 keystore::AuthorizationSet* output_parameters, std::string* output_data) = 0; 155 156 // Finishes the operation associated with |handle| using the given 157 // |input_parameters| and, if necessary, a |signature_to_verify|. On success, 158 // any |output_parameters| are populated and |output_data| is appended. 159 // Returns KM_ERROR_OK on success and a Keystore ResponseCode or 160 // keymaster_error_t on failure. 161 virtual KeyStoreNativeReturnCode 162 finishOperation(uint64_t handle, const keystore::AuthorizationSet& input_parameters, 163 const std::string& input_data, const std::string& signature_to_verify, 164 keystore::AuthorizationSet* output_parameters, std::string* output_data) = 0; 165 166 // Aborts the operation associated with |handle|. Returns KM_ERROR_OK on 167 // success and a Keystore ResponseCode or keymaster_error_t on failure. 168 virtual KeyStoreNativeReturnCode abortOperation(uint64_t handle) = 0; 169 170 // Returns true if a key identified by |key_name| exists in the caller's 171 // key store. Returns false if an error occurs. 172 virtual bool doesKeyExist(const std::string& key_name) = 0; 173 174 // Provides a |key_name_list| containing all existing key names in the 175 // caller's key store starting with |prefix|. Returns true on success. 176 virtual bool listKeys(const std::string& prefix, std::vector<std::string>* key_name_list) = 0; 177 178 // Provides a |key_name_list| containing all existing key names in the 179 // caller's key store starting with |prefix|. Returns true on success. 180 virtual bool listKeysOfUid(const std::string& prefix, int uid, 181 std::vector<std::string>* key_name_list) = 0; 182 183 virtual std::optional<std::vector<uint8_t>> getKey(const std::string& alias, int uid) = 0; 184 185 private: 186 DISALLOW_COPY_AND_ASSIGN(KeystoreClient); 187 }; 188 189 } // namespace keystore 190 191 #endif // KEYSTORE_KEYSTORE_CLIENT_H_ 192