1 /** @file 2 Implement authentication services for the authenticated variables. 3 4 Caution: This module requires additional review when modified. 5 This driver will have external input - variable data. It may be input in SMM mode. 6 This external input must be validated carefully to avoid security issue like 7 buffer overflow, integer overflow. 8 Variable attribute should also be checked to avoid authentication bypass. 9 The whole SMM authentication variable design relies on the integrity of flash part and SMM. 10 which is assumed to be protected by platform. All variable code and metadata in flash/SMM Memory 11 may not be modified without authorization. If platform fails to protect these resources, 12 the authentication service provided in this driver will be broken, and the behavior is undefined. 13 14 Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.<BR> 15 This program and the accompanying materials 16 are licensed and made available under the terms and conditions of the BSD License 17 which accompanies this distribution. The full text of the license may be found at 18 http://opensource.org/licenses/bsd-license.php 19 20 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 21 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 22 23 **/ 24 25 #include "AuthServiceInternal.h" 26 27 /// 28 /// Global database array for scratch 29 /// 30 UINT8 *mPubKeyStore; 31 UINT32 mPubKeyNumber; 32 UINT32 mMaxKeyNumber; 33 UINT32 mMaxKeyDbSize; 34 UINT8 *mCertDbStore; 35 UINT32 mMaxCertDbSize; 36 UINT32 mPlatformMode; 37 UINT8 mVendorKeyState; 38 39 EFI_GUID mSignatureSupport[] = {EFI_CERT_SHA1_GUID, EFI_CERT_SHA256_GUID, EFI_CERT_RSA2048_GUID, EFI_CERT_X509_GUID}; 40 41 // 42 // Hash context pointer 43 // 44 VOID *mHashCtx = NULL; 45 46 VARIABLE_ENTRY_PROPERTY mAuthVarEntry[] = { 47 { 48 &gEfiSecureBootEnableDisableGuid, 49 EFI_SECURE_BOOT_ENABLE_NAME, 50 { 51 VAR_CHECK_VARIABLE_PROPERTY_REVISION, 52 0, 53 VARIABLE_ATTRIBUTE_NV_BS, 54 sizeof (UINT8), 55 sizeof (UINT8) 56 } 57 }, 58 { 59 &gEfiCustomModeEnableGuid, 60 EFI_CUSTOM_MODE_NAME, 61 { 62 VAR_CHECK_VARIABLE_PROPERTY_REVISION, 63 0, 64 VARIABLE_ATTRIBUTE_NV_BS, 65 sizeof (UINT8), 66 sizeof (UINT8) 67 } 68 }, 69 { 70 &gEfiVendorKeysNvGuid, 71 EFI_VENDOR_KEYS_NV_VARIABLE_NAME, 72 { 73 VAR_CHECK_VARIABLE_PROPERTY_REVISION, 74 VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY, 75 VARIABLE_ATTRIBUTE_NV_BS_RT_AT, 76 sizeof (UINT8), 77 sizeof (UINT8) 78 } 79 }, 80 { 81 &gEfiAuthenticatedVariableGuid, 82 AUTHVAR_KEYDB_NAME, 83 { 84 VAR_CHECK_VARIABLE_PROPERTY_REVISION, 85 VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY, 86 VARIABLE_ATTRIBUTE_NV_BS_RT_AW, 87 sizeof (UINT8), 88 MAX_UINTN 89 } 90 }, 91 { 92 &gEfiCertDbGuid, 93 EFI_CERT_DB_NAME, 94 { 95 VAR_CHECK_VARIABLE_PROPERTY_REVISION, 96 VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY, 97 VARIABLE_ATTRIBUTE_NV_BS_RT_AT, 98 sizeof (UINT32), 99 MAX_UINTN 100 } 101 }, 102 { 103 &gEfiCertDbGuid, 104 EFI_CERT_DB_VOLATILE_NAME, 105 { 106 VAR_CHECK_VARIABLE_PROPERTY_REVISION, 107 VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY, 108 VARIABLE_ATTRIBUTE_BS_RT_AT, 109 sizeof (UINT32), 110 MAX_UINTN 111 } 112 }, 113 }; 114 115 VOID **mAuthVarAddressPointer[10]; 116 117 AUTH_VAR_LIB_CONTEXT_IN *mAuthVarLibContextIn = NULL; 118 119 /** 120 Initialization for authenticated varibale services. 121 If this initialization returns error status, other APIs will not work 122 and expect to be not called then. 123 124 @param[in] AuthVarLibContextIn Pointer to input auth variable lib context. 125 @param[out] AuthVarLibContextOut Pointer to output auth variable lib context. 126 127 @retval EFI_SUCCESS Function successfully executed. 128 @retval EFI_INVALID_PARAMETER If AuthVarLibContextIn == NULL or AuthVarLibContextOut == NULL. 129 @retval EFI_OUT_OF_RESOURCES Fail to allocate enough resource. 130 @retval EFI_UNSUPPORTED Unsupported to process authenticated variable. 131 132 **/ 133 EFI_STATUS 134 EFIAPI 135 AuthVariableLibInitialize ( 136 IN AUTH_VAR_LIB_CONTEXT_IN *AuthVarLibContextIn, 137 OUT AUTH_VAR_LIB_CONTEXT_OUT *AuthVarLibContextOut 138 ) 139 { 140 EFI_STATUS Status; 141 UINT8 VarValue; 142 UINT32 VarAttr; 143 UINT8 *Data; 144 UINTN DataSize; 145 UINTN CtxSize; 146 UINT8 SecureBootMode; 147 UINT8 SecureBootEnable; 148 UINT8 CustomMode; 149 UINT32 ListSize; 150 151 if ((AuthVarLibContextIn == NULL) || (AuthVarLibContextOut == NULL)) { 152 return EFI_INVALID_PARAMETER; 153 } 154 155 mAuthVarLibContextIn = AuthVarLibContextIn; 156 157 // 158 // Initialize hash context. 159 // 160 CtxSize = Sha256GetContextSize (); 161 mHashCtx = AllocateRuntimePool (CtxSize); 162 if (mHashCtx == NULL) { 163 return EFI_OUT_OF_RESOURCES; 164 } 165 166 // 167 // Reserve runtime buffer for public key database. The size excludes variable header and name size. 168 // 169 mMaxKeyDbSize = (UINT32) (mAuthVarLibContextIn->MaxAuthVariableSize - sizeof (AUTHVAR_KEYDB_NAME)); 170 mMaxKeyNumber = mMaxKeyDbSize / sizeof (AUTHVAR_KEY_DB_DATA); 171 mPubKeyStore = AllocateRuntimePool (mMaxKeyDbSize); 172 if (mPubKeyStore == NULL) { 173 return EFI_OUT_OF_RESOURCES; 174 } 175 176 // 177 // Reserve runtime buffer for certificate database. The size excludes variable header and name size. 178 // Use EFI_CERT_DB_VOLATILE_NAME size since it is longer. 179 // 180 mMaxCertDbSize = (UINT32) (mAuthVarLibContextIn->MaxAuthVariableSize - sizeof (EFI_CERT_DB_VOLATILE_NAME)); 181 mCertDbStore = AllocateRuntimePool (mMaxCertDbSize); 182 if (mCertDbStore == NULL) { 183 return EFI_OUT_OF_RESOURCES; 184 } 185 186 // 187 // Check "AuthVarKeyDatabase" variable's existence. 188 // If it doesn't exist, create a new one with initial value of 0 and EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS set. 189 // 190 Status = AuthServiceInternalFindVariable ( 191 AUTHVAR_KEYDB_NAME, 192 &gEfiAuthenticatedVariableGuid, 193 (VOID **) &Data, 194 &DataSize 195 ); 196 if (EFI_ERROR (Status)) { 197 VarAttr = EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS; 198 VarValue = 0; 199 mPubKeyNumber = 0; 200 Status = AuthServiceInternalUpdateVariable ( 201 AUTHVAR_KEYDB_NAME, 202 &gEfiAuthenticatedVariableGuid, 203 &VarValue, 204 sizeof(UINT8), 205 VarAttr 206 ); 207 if (EFI_ERROR (Status)) { 208 return Status; 209 } 210 } else { 211 // 212 // Load database in global variable for cache. 213 // 214 ASSERT ((DataSize != 0) && (Data != NULL)); 215 // 216 // "AuthVarKeyDatabase" is an internal variable. Its DataSize is always ensured not to exceed mPubKeyStore buffer size(See definition before) 217 // Therefore, there is no memory overflow in underlying CopyMem. 218 // 219 CopyMem (mPubKeyStore, (UINT8 *) Data, DataSize); 220 mPubKeyNumber = (UINT32) (DataSize / sizeof (AUTHVAR_KEY_DB_DATA)); 221 } 222 223 Status = AuthServiceInternalFindVariable (EFI_PLATFORM_KEY_NAME, &gEfiGlobalVariableGuid, (VOID **) &Data, &DataSize); 224 if (EFI_ERROR (Status)) { 225 DEBUG ((EFI_D_INFO, "Variable %s does not exist.\n", EFI_PLATFORM_KEY_NAME)); 226 } else { 227 DEBUG ((EFI_D_INFO, "Variable %s exists.\n", EFI_PLATFORM_KEY_NAME)); 228 } 229 230 // 231 // Create "SetupMode" variable with BS+RT attribute set. 232 // 233 if (EFI_ERROR (Status)) { 234 mPlatformMode = SETUP_MODE; 235 } else { 236 mPlatformMode = USER_MODE; 237 } 238 Status = AuthServiceInternalUpdateVariable ( 239 EFI_SETUP_MODE_NAME, 240 &gEfiGlobalVariableGuid, 241 &mPlatformMode, 242 sizeof(UINT8), 243 EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS 244 ); 245 if (EFI_ERROR (Status)) { 246 return Status; 247 } 248 249 // 250 // Create "SignatureSupport" variable with BS+RT attribute set. 251 // 252 Status = AuthServiceInternalUpdateVariable ( 253 EFI_SIGNATURE_SUPPORT_NAME, 254 &gEfiGlobalVariableGuid, 255 mSignatureSupport, 256 sizeof(mSignatureSupport), 257 EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS 258 ); 259 if (EFI_ERROR (Status)) { 260 return Status; 261 } 262 263 // 264 // If "SecureBootEnable" variable exists, then update "SecureBoot" variable. 265 // If "SecureBootEnable" variable is SECURE_BOOT_ENABLE and in USER_MODE, Set "SecureBoot" variable to SECURE_BOOT_MODE_ENABLE. 266 // If "SecureBootEnable" variable is SECURE_BOOT_DISABLE, Set "SecureBoot" variable to SECURE_BOOT_MODE_DISABLE. 267 // 268 SecureBootEnable = SECURE_BOOT_DISABLE; 269 Status = AuthServiceInternalFindVariable (EFI_SECURE_BOOT_ENABLE_NAME, &gEfiSecureBootEnableDisableGuid, (VOID **) &Data, &DataSize); 270 if (!EFI_ERROR (Status)) { 271 if (mPlatformMode == USER_MODE){ 272 SecureBootEnable = *(UINT8 *) Data; 273 } 274 } else if (mPlatformMode == USER_MODE) { 275 // 276 // "SecureBootEnable" not exist, initialize it in USER_MODE. 277 // 278 SecureBootEnable = SECURE_BOOT_ENABLE; 279 Status = AuthServiceInternalUpdateVariable ( 280 EFI_SECURE_BOOT_ENABLE_NAME, 281 &gEfiSecureBootEnableDisableGuid, 282 &SecureBootEnable, 283 sizeof (UINT8), 284 EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS 285 ); 286 if (EFI_ERROR (Status)) { 287 return Status; 288 } 289 } 290 291 // 292 // Create "SecureBoot" variable with BS+RT attribute set. 293 // 294 if (SecureBootEnable == SECURE_BOOT_ENABLE && mPlatformMode == USER_MODE) { 295 SecureBootMode = SECURE_BOOT_MODE_ENABLE; 296 } else { 297 SecureBootMode = SECURE_BOOT_MODE_DISABLE; 298 } 299 Status = AuthServiceInternalUpdateVariable ( 300 EFI_SECURE_BOOT_MODE_NAME, 301 &gEfiGlobalVariableGuid, 302 &SecureBootMode, 303 sizeof (UINT8), 304 EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS 305 ); 306 if (EFI_ERROR (Status)) { 307 return Status; 308 } 309 310 DEBUG ((EFI_D_INFO, "Variable %s is %x\n", EFI_SETUP_MODE_NAME, mPlatformMode)); 311 DEBUG ((EFI_D_INFO, "Variable %s is %x\n", EFI_SECURE_BOOT_MODE_NAME, SecureBootMode)); 312 DEBUG ((EFI_D_INFO, "Variable %s is %x\n", EFI_SECURE_BOOT_ENABLE_NAME, SecureBootEnable)); 313 314 // 315 // Initialize "CustomMode" in STANDARD_SECURE_BOOT_MODE state. 316 // 317 CustomMode = STANDARD_SECURE_BOOT_MODE; 318 Status = AuthServiceInternalUpdateVariable ( 319 EFI_CUSTOM_MODE_NAME, 320 &gEfiCustomModeEnableGuid, 321 &CustomMode, 322 sizeof (UINT8), 323 EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS 324 ); 325 if (EFI_ERROR (Status)) { 326 return Status; 327 } 328 329 DEBUG ((EFI_D_INFO, "Variable %s is %x\n", EFI_CUSTOM_MODE_NAME, CustomMode)); 330 331 // 332 // Check "certdb" variable's existence. 333 // If it doesn't exist, then create a new one with 334 // EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS set. 335 // 336 Status = AuthServiceInternalFindVariable ( 337 EFI_CERT_DB_NAME, 338 &gEfiCertDbGuid, 339 (VOID **) &Data, 340 &DataSize 341 ); 342 if (EFI_ERROR (Status)) { 343 VarAttr = EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS; 344 ListSize = sizeof (UINT32); 345 Status = AuthServiceInternalUpdateVariable ( 346 EFI_CERT_DB_NAME, 347 &gEfiCertDbGuid, 348 &ListSize, 349 sizeof (UINT32), 350 VarAttr 351 ); 352 if (EFI_ERROR (Status)) { 353 return Status; 354 } 355 } else { 356 // 357 // Clean up Certs to make certDB & Time based auth variable consistent 358 // 359 Status = CleanCertsFromDb(); 360 if (EFI_ERROR (Status)) { 361 DEBUG ((EFI_D_ERROR, "Clean up CertDB fail! Status %x\n", Status)); 362 return Status; 363 } 364 } 365 366 // 367 // Create "certdbv" variable with RT+BS+AT set. 368 // 369 VarAttr = EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS; 370 ListSize = sizeof (UINT32); 371 Status = AuthServiceInternalUpdateVariable ( 372 EFI_CERT_DB_VOLATILE_NAME, 373 &gEfiCertDbGuid, 374 &ListSize, 375 sizeof (UINT32), 376 VarAttr 377 ); 378 if (EFI_ERROR (Status)) { 379 return Status; 380 } 381 382 // 383 // Check "VendorKeysNv" variable's existence and create "VendorKeys" variable accordingly. 384 // 385 Status = AuthServiceInternalFindVariable (EFI_VENDOR_KEYS_NV_VARIABLE_NAME, &gEfiVendorKeysNvGuid, (VOID **) &Data, &DataSize); 386 if (!EFI_ERROR (Status)) { 387 mVendorKeyState = *(UINT8 *)Data; 388 } else { 389 // 390 // "VendorKeysNv" not exist, initialize it in VENDOR_KEYS_VALID state. 391 // 392 mVendorKeyState = VENDOR_KEYS_VALID; 393 Status = AuthServiceInternalUpdateVariable ( 394 EFI_VENDOR_KEYS_NV_VARIABLE_NAME, 395 &gEfiVendorKeysNvGuid, 396 &mVendorKeyState, 397 sizeof (UINT8), 398 EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS 399 ); 400 if (EFI_ERROR (Status)) { 401 return Status; 402 } 403 } 404 405 // 406 // Create "VendorKeys" variable with BS+RT attribute set. 407 // 408 Status = AuthServiceInternalUpdateVariable ( 409 EFI_VENDOR_KEYS_VARIABLE_NAME, 410 &gEfiGlobalVariableGuid, 411 &mVendorKeyState, 412 sizeof (UINT8), 413 EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS 414 ); 415 if (EFI_ERROR (Status)) { 416 return Status; 417 } 418 419 DEBUG ((EFI_D_INFO, "Variable %s is %x\n", EFI_VENDOR_KEYS_VARIABLE_NAME, mVendorKeyState)); 420 421 AuthVarLibContextOut->StructVersion = AUTH_VAR_LIB_CONTEXT_OUT_STRUCT_VERSION; 422 AuthVarLibContextOut->StructSize = sizeof (AUTH_VAR_LIB_CONTEXT_OUT); 423 AuthVarLibContextOut->AuthVarEntry = mAuthVarEntry; 424 AuthVarLibContextOut->AuthVarEntryCount = ARRAY_SIZE (mAuthVarEntry); 425 mAuthVarAddressPointer[0] = (VOID **) &mPubKeyStore; 426 mAuthVarAddressPointer[1] = (VOID **) &mCertDbStore; 427 mAuthVarAddressPointer[2] = (VOID **) &mHashCtx; 428 mAuthVarAddressPointer[3] = (VOID **) &mAuthVarLibContextIn; 429 mAuthVarAddressPointer[4] = (VOID **) &(mAuthVarLibContextIn->FindVariable), 430 mAuthVarAddressPointer[5] = (VOID **) &(mAuthVarLibContextIn->FindNextVariable), 431 mAuthVarAddressPointer[6] = (VOID **) &(mAuthVarLibContextIn->UpdateVariable), 432 mAuthVarAddressPointer[7] = (VOID **) &(mAuthVarLibContextIn->GetScratchBuffer), 433 mAuthVarAddressPointer[8] = (VOID **) &(mAuthVarLibContextIn->CheckRemainingSpaceForConsistency), 434 mAuthVarAddressPointer[9] = (VOID **) &(mAuthVarLibContextIn->AtRuntime), 435 AuthVarLibContextOut->AddressPointer = mAuthVarAddressPointer; 436 AuthVarLibContextOut->AddressPointerCount = ARRAY_SIZE (mAuthVarAddressPointer); 437 438 return Status; 439 } 440 441 /** 442 Process variable with EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS/EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS set. 443 444 @param[in] VariableName Name of the variable. 445 @param[in] VendorGuid Variable vendor GUID. 446 @param[in] Data Data pointer. 447 @param[in] DataSize Size of Data. 448 @param[in] Attributes Attribute value of the variable. 449 450 @retval EFI_SUCCESS The firmware has successfully stored the variable and its data as 451 defined by the Attributes. 452 @retval EFI_INVALID_PARAMETER Invalid parameter. 453 @retval EFI_WRITE_PROTECTED Variable is write-protected. 454 @retval EFI_OUT_OF_RESOURCES There is not enough resource. 455 @retval EFI_SECURITY_VIOLATION The variable is with EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS 456 or EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACESS 457 set, but the AuthInfo does NOT pass the validation 458 check carried out by the firmware. 459 @retval EFI_UNSUPPORTED Unsupported to process authenticated variable. 460 461 **/ 462 EFI_STATUS 463 EFIAPI 464 AuthVariableLibProcessVariable ( 465 IN CHAR16 *VariableName, 466 IN EFI_GUID *VendorGuid, 467 IN VOID *Data, 468 IN UINTN DataSize, 469 IN UINT32 Attributes 470 ) 471 { 472 EFI_STATUS Status; 473 474 if (CompareGuid (VendorGuid, &gEfiGlobalVariableGuid) && (StrCmp (VariableName, EFI_PLATFORM_KEY_NAME) == 0)){ 475 Status = ProcessVarWithPk (VariableName, VendorGuid, Data, DataSize, Attributes, TRUE); 476 } else if (CompareGuid (VendorGuid, &gEfiGlobalVariableGuid) && (StrCmp (VariableName, EFI_KEY_EXCHANGE_KEY_NAME) == 0)) { 477 Status = ProcessVarWithPk (VariableName, VendorGuid, Data, DataSize, Attributes, FALSE); 478 } else if (CompareGuid (VendorGuid, &gEfiImageSecurityDatabaseGuid) && 479 ((StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE) == 0) || 480 (StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE1) == 0) || 481 (StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE2) == 0) 482 )) { 483 Status = ProcessVarWithPk (VariableName, VendorGuid, Data, DataSize, Attributes, FALSE); 484 if (EFI_ERROR (Status)) { 485 Status = ProcessVarWithKek (VariableName, VendorGuid, Data, DataSize, Attributes); 486 } 487 } else { 488 Status = ProcessVariable (VariableName, VendorGuid, Data, DataSize, Attributes); 489 } 490 491 return Status; 492 } 493
