1 /* 2 * Copyright 2016 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 #ifndef SYSTEM_KEYMASTER_ATTESTATION_RECORD_H_ 18 #define SYSTEM_KEYMASTER_ATTESTATION_RECORD_H_ 19 20 #include <hardware/keymaster_defs.h> 21 22 #include <keymaster/authorization_set.h> 23 24 #include <openssl/asn1t.h> 25 26 namespace keymaster { 27 28 struct stack_st_ASN1_TYPE_Delete { 29 void operator()(stack_st_ASN1_TYPE* p) { sk_ASN1_TYPE_free(p); } 30 }; 31 32 struct ASN1_STRING_Delete { 33 void operator()(ASN1_STRING* p) { ASN1_STRING_free(p); } 34 }; 35 36 struct ASN1_TYPE_Delete { 37 void operator()(ASN1_TYPE* p) { ASN1_TYPE_free(p); } 38 }; 39 40 #define ASN1_INTEGER_SET STACK_OF(ASN1_INTEGER) 41 42 typedef struct km_root_of_trust { 43 ASN1_OCTET_STRING* verified_boot_key; 44 ASN1_BOOLEAN* device_locked; 45 ASN1_ENUMERATED* verified_boot_state; 46 } KM_ROOT_OF_TRUST; 47 48 ASN1_SEQUENCE(KM_ROOT_OF_TRUST) = { 49 ASN1_SIMPLE(KM_ROOT_OF_TRUST, verified_boot_key, ASN1_OCTET_STRING), 50 ASN1_SIMPLE(KM_ROOT_OF_TRUST, device_locked, ASN1_BOOLEAN), 51 ASN1_SIMPLE(KM_ROOT_OF_TRUST, verified_boot_state, ASN1_ENUMERATED), 52 } ASN1_SEQUENCE_END(KM_ROOT_OF_TRUST); 53 DECLARE_ASN1_FUNCTIONS(KM_ROOT_OF_TRUST); 54 55 typedef struct km_auth_list { 56 ASN1_INTEGER_SET* purpose; 57 ASN1_INTEGER* algorithm; 58 ASN1_INTEGER* key_size; 59 ASN1_INTEGER_SET* block_mode; 60 ASN1_INTEGER_SET* digest; 61 ASN1_INTEGER_SET* padding; 62 ASN1_NULL* caller_nonce; 63 ASN1_INTEGER* min_mac_length; 64 ASN1_INTEGER_SET* kdf; 65 ASN1_INTEGER* ec_curve; 66 ASN1_INTEGER* rsa_public_exponent; 67 ASN1_INTEGER* active_date_time; 68 ASN1_INTEGER* origination_expire_date_time; 69 ASN1_INTEGER* usage_expire_date_time; 70 ASN1_NULL* no_auth_required; 71 ASN1_INTEGER* user_auth_type; 72 ASN1_INTEGER* auth_timeout; 73 ASN1_NULL* allow_while_on_body; 74 ASN1_NULL* unlocked_device_required; 75 ASN1_NULL* all_applications; 76 ASN1_OCTET_STRING* application_id; 77 ASN1_INTEGER* creation_date_time; 78 ASN1_INTEGER* origin; 79 ASN1_NULL* rollback_resistant; 80 KM_ROOT_OF_TRUST* root_of_trust; 81 ASN1_INTEGER* os_version; 82 ASN1_INTEGER* os_patchlevel; 83 ASN1_OCTET_STRING* attestation_application_id; 84 ASN1_OCTET_STRING* attestation_id_brand; 85 ASN1_OCTET_STRING* attestation_id_device; 86 ASN1_OCTET_STRING* attestation_id_product; 87 ASN1_OCTET_STRING* attestation_id_serial; 88 ASN1_OCTET_STRING* attestation_id_imei; 89 ASN1_OCTET_STRING* attestation_id_meid; 90 ASN1_OCTET_STRING* attestation_id_manufacturer; 91 ASN1_OCTET_STRING* attestation_id_model; 92 } KM_AUTH_LIST; 93 94 ASN1_SEQUENCE(KM_AUTH_LIST) = { 95 ASN1_EXP_SET_OF_OPT(KM_AUTH_LIST, purpose, ASN1_INTEGER, TAG_PURPOSE.masked_tag()), 96 ASN1_EXP_OPT(KM_AUTH_LIST, algorithm, ASN1_INTEGER, TAG_ALGORITHM.masked_tag()), 97 ASN1_EXP_OPT(KM_AUTH_LIST, key_size, ASN1_INTEGER, TAG_KEY_SIZE.masked_tag()), 98 ASN1_EXP_SET_OF_OPT(KM_AUTH_LIST, block_mode, ASN1_INTEGER, TAG_BLOCK_MODE.masked_tag()), 99 ASN1_EXP_SET_OF_OPT(KM_AUTH_LIST, digest, ASN1_INTEGER, TAG_DIGEST.masked_tag()), 100 ASN1_EXP_SET_OF_OPT(KM_AUTH_LIST, padding, ASN1_INTEGER, TAG_PADDING.masked_tag()), 101 ASN1_EXP_OPT(KM_AUTH_LIST, caller_nonce, ASN1_NULL, TAG_CALLER_NONCE.masked_tag()), 102 ASN1_EXP_OPT(KM_AUTH_LIST, min_mac_length, ASN1_INTEGER, TAG_MIN_MAC_LENGTH.masked_tag()), 103 ASN1_EXP_SET_OF_OPT(KM_AUTH_LIST, kdf, ASN1_INTEGER, TAG_KDF.masked_tag()), 104 ASN1_EXP_OPT(KM_AUTH_LIST, ec_curve, ASN1_INTEGER, TAG_EC_CURVE.masked_tag()), 105 ASN1_EXP_OPT(KM_AUTH_LIST, rsa_public_exponent, ASN1_INTEGER, 106 TAG_RSA_PUBLIC_EXPONENT.masked_tag()), 107 ASN1_EXP_OPT(KM_AUTH_LIST, active_date_time, ASN1_INTEGER, TAG_ACTIVE_DATETIME.masked_tag()), 108 ASN1_EXP_OPT(KM_AUTH_LIST, origination_expire_date_time, ASN1_INTEGER, 109 TAG_ORIGINATION_EXPIRE_DATETIME.masked_tag()), 110 ASN1_EXP_OPT(KM_AUTH_LIST, usage_expire_date_time, ASN1_INTEGER, 111 TAG_USAGE_EXPIRE_DATETIME.masked_tag()), 112 ASN1_EXP_OPT(KM_AUTH_LIST, no_auth_required, ASN1_NULL, TAG_NO_AUTH_REQUIRED.masked_tag()), 113 ASN1_EXP_OPT(KM_AUTH_LIST, user_auth_type, ASN1_INTEGER, TAG_USER_AUTH_TYPE.masked_tag()), 114 ASN1_EXP_OPT(KM_AUTH_LIST, auth_timeout, ASN1_INTEGER, TAG_AUTH_TIMEOUT.masked_tag()), 115 ASN1_EXP_OPT(KM_AUTH_LIST, allow_while_on_body, ASN1_NULL, 116 TAG_ALLOW_WHILE_ON_BODY.masked_tag()), 117 ASN1_EXP_OPT(KM_AUTH_LIST, all_applications, ASN1_NULL, TAG_ALL_APPLICATIONS.masked_tag()), 118 ASN1_EXP_OPT(KM_AUTH_LIST, application_id, ASN1_OCTET_STRING, TAG_APPLICATION_ID.masked_tag()), 119 ASN1_EXP_OPT(KM_AUTH_LIST, creation_date_time, ASN1_INTEGER, 120 TAG_CREATION_DATETIME.masked_tag()), 121 ASN1_EXP_OPT(KM_AUTH_LIST, origin, ASN1_INTEGER, TAG_ORIGIN.masked_tag()), 122 ASN1_EXP_OPT(KM_AUTH_LIST, rollback_resistant, ASN1_NULL, TAG_ROLLBACK_RESISTANT.masked_tag()), 123 ASN1_EXP_OPT(KM_AUTH_LIST, root_of_trust, KM_ROOT_OF_TRUST, TAG_ROOT_OF_TRUST.masked_tag()), 124 ASN1_EXP_OPT(KM_AUTH_LIST, os_version, ASN1_INTEGER, TAG_OS_VERSION.masked_tag()), 125 ASN1_EXP_OPT(KM_AUTH_LIST, os_patchlevel, ASN1_INTEGER, TAG_OS_PATCHLEVEL.masked_tag()), 126 ASN1_EXP_OPT(KM_AUTH_LIST, attestation_application_id, ASN1_OCTET_STRING, 127 TAG_ATTESTATION_APPLICATION_ID.masked_tag()), 128 ASN1_EXP_OPT(KM_AUTH_LIST, attestation_id_brand, ASN1_OCTET_STRING, 129 TAG_ATTESTATION_ID_BRAND.masked_tag()), 130 ASN1_EXP_OPT(KM_AUTH_LIST, attestation_id_device, ASN1_OCTET_STRING, 131 TAG_ATTESTATION_ID_DEVICE.masked_tag()), 132 ASN1_EXP_OPT(KM_AUTH_LIST, attestation_id_product, ASN1_OCTET_STRING, 133 TAG_ATTESTATION_ID_PRODUCT.masked_tag()), 134 ASN1_EXP_OPT(KM_AUTH_LIST, attestation_id_serial, ASN1_OCTET_STRING, 135 TAG_ATTESTATION_ID_SERIAL.masked_tag()), 136 ASN1_EXP_OPT(KM_AUTH_LIST, attestation_id_imei, ASN1_OCTET_STRING, 137 TAG_ATTESTATION_ID_IMEI.masked_tag()), 138 ASN1_EXP_OPT(KM_AUTH_LIST, attestation_id_meid, ASN1_OCTET_STRING, 139 TAG_ATTESTATION_ID_MEID.masked_tag()), 140 ASN1_EXP_OPT(KM_AUTH_LIST, attestation_id_manufacturer, ASN1_OCTET_STRING, 141 TAG_ATTESTATION_ID_MANUFACTURER.masked_tag()), 142 ASN1_EXP_OPT(KM_AUTH_LIST, attestation_id_model, ASN1_OCTET_STRING, 143 TAG_ATTESTATION_ID_MODEL.masked_tag()), 144 } ASN1_SEQUENCE_END(KM_AUTH_LIST); 145 DECLARE_ASN1_FUNCTIONS(KM_AUTH_LIST); 146 147 typedef struct km_key_description { 148 ASN1_INTEGER* attestation_version; 149 ASN1_ENUMERATED* attestation_security_level; 150 ASN1_INTEGER* keymaster_version; 151 ASN1_ENUMERATED* keymaster_security_level; 152 ASN1_OCTET_STRING* attestation_challenge; 153 KM_AUTH_LIST* software_enforced; 154 KM_AUTH_LIST* tee_enforced; 155 ASN1_INTEGER* unique_id; 156 } KM_KEY_DESCRIPTION; 157 158 ASN1_SEQUENCE(KM_KEY_DESCRIPTION) = { 159 ASN1_SIMPLE(KM_KEY_DESCRIPTION, attestation_version, ASN1_INTEGER), 160 ASN1_SIMPLE(KM_KEY_DESCRIPTION, attestation_security_level, ASN1_ENUMERATED), 161 ASN1_SIMPLE(KM_KEY_DESCRIPTION, keymaster_version, ASN1_INTEGER), 162 ASN1_SIMPLE(KM_KEY_DESCRIPTION, keymaster_security_level, ASN1_ENUMERATED), 163 ASN1_SIMPLE(KM_KEY_DESCRIPTION, attestation_challenge, ASN1_OCTET_STRING), 164 ASN1_SIMPLE(KM_KEY_DESCRIPTION, unique_id, ASN1_OCTET_STRING), 165 ASN1_SIMPLE(KM_KEY_DESCRIPTION, software_enforced, KM_AUTH_LIST), 166 ASN1_SIMPLE(KM_KEY_DESCRIPTION, tee_enforced, KM_AUTH_LIST), 167 } ASN1_SEQUENCE_END(KM_KEY_DESCRIPTION); 168 DECLARE_ASN1_FUNCTIONS(KM_KEY_DESCRIPTION); 169 170 class AttestationRecordContext { 171 protected: 172 virtual ~AttestationRecordContext() {} 173 174 public: 175 /** 176 * Returns the security level (SW or TEE) of this keymaster implementation. 177 */ 178 virtual keymaster_security_level_t GetSecurityLevel() const { 179 return KM_SECURITY_LEVEL_SOFTWARE; 180 } 181 182 /** 183 * Verify that the device IDs provided in the attestation_params match the device's actual IDs 184 * and copy them to attestation. If *any* of the IDs do not match or verification is not 185 * possible, return KM_ERROR_CANNOT_ATTEST_IDS. If *all* IDs provided are successfully verified 186 * or no IDs were provided, return KM_ERROR_OK. 187 * 188 * If you do not support device ID attestation, ignore all arguments and return 189 * KM_ERROR_UNIMPLEMENTED. 190 */ 191 virtual keymaster_error_t 192 VerifyAndCopyDeviceIds(const AuthorizationSet& /* attestation_params */, 193 AuthorizationSet* /* attestation */) const { 194 return KM_ERROR_UNIMPLEMENTED; 195 } 196 /** 197 * Generate the current unique ID. 198 */ 199 virtual keymaster_error_t GenerateUniqueId(uint64_t /*creation_date_time*/, 200 const keymaster_blob_t& /*application_id*/, 201 bool /*reset_since_rotation*/, 202 Buffer* /*unique_id*/) const { 203 return KM_ERROR_UNIMPLEMENTED; 204 } 205 206 /** 207 * Returns verified boot parameters for the Attestation Extension. For hardware-based 208 * implementations, these will be the values reported by the bootloader. By default, verified 209 * boot state is unknown, and KM_ERROR_UNIMPLEMENTED is returned. 210 */ 211 virtual keymaster_error_t 212 GetVerifiedBootParams(keymaster_blob_t* /* verified_boot_key */, 213 keymaster_verified_boot_t* /* verified_boot_state */, 214 bool* /* device_locked */) const { 215 return KM_ERROR_UNIMPLEMENTED; 216 } 217 }; 218 219 /** 220 * The OID for Android attestation records. For the curious, it breaks down as follows: 221 * 222 * 1 = ISO 223 * 3 = org 224 * 6 = DoD (Huh? OIDs are weird.) 225 * 1 = IANA 226 * 4 = Private 227 * 1 = Enterprises 228 * 11129 = Google 229 * 2 = Google security 230 * 1 = certificate extension 231 * 17 = Android attestation extension. 232 */ 233 static const char kAttestionRecordOid[] = "1.3.6.1.4.1.11129.2.1.17"; 234 235 keymaster_error_t build_attestation_record(const AuthorizationSet& attestation_params, 236 AuthorizationSet software_enforced, 237 AuthorizationSet tee_enforced, 238 const AttestationRecordContext& context, 239 UniquePtr<uint8_t[]>* asn1_key_desc, 240 size_t* asn1_key_desc_len); 241 242 /** 243 * helper function for attestation record test. 244 */ 245 keymaster_error_t parse_attestation_record(const uint8_t* asn1_key_desc, size_t asn1_key_desc_len, 246 uint32_t* attestation_version, // 247 keymaster_security_level_t* attestation_security_level, 248 uint32_t* keymaster_version, 249 keymaster_security_level_t* keymaster_security_level, 250 keymaster_blob_t* attestation_challenge, 251 AuthorizationSet* software_enforced, 252 AuthorizationSet* tee_enforced, 253 keymaster_blob_t* unique_id); 254 255 keymaster_error_t build_auth_list(const AuthorizationSet& auth_list, KM_AUTH_LIST* record); 256 257 keymaster_error_t extract_auth_list(const KM_AUTH_LIST* record, AuthorizationSet* auth_list); 258 } // namespace keymaster 259 260 #endif // SYSTEM_KEYMASTER_ATTESTATION_RECORD_H_ 261
