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, 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 UINT8 mVendorKeyState; 37 38 EFI_GUID mSignatureSupport[] = {EFI_CERT_SHA1_GUID, EFI_CERT_SHA256_GUID, EFI_CERT_RSA2048_GUID, EFI_CERT_X509_GUID}; 39 40 // 41 // Hash context pointer 42 // 43 VOID *mHashCtx = NULL; 44 45 VARIABLE_ENTRY_PROPERTY mAuthVarEntry[] = { 46 { 47 &gEfiSecureBootEnableDisableGuid, 48 EFI_SECURE_BOOT_ENABLE_NAME, 49 { 50 VAR_CHECK_VARIABLE_PROPERTY_REVISION, 51 0, 52 VARIABLE_ATTRIBUTE_NV_BS, 53 sizeof (UINT8), 54 sizeof (UINT8) 55 } 56 }, 57 { 58 &gEfiCustomModeEnableGuid, 59 EFI_CUSTOM_MODE_NAME, 60 { 61 VAR_CHECK_VARIABLE_PROPERTY_REVISION, 62 0, 63 VARIABLE_ATTRIBUTE_NV_BS, 64 sizeof (UINT8), 65 sizeof (UINT8) 66 } 67 }, 68 { 69 &gEfiVendorKeysNvGuid, 70 EFI_VENDOR_KEYS_NV_VARIABLE_NAME, 71 { 72 VAR_CHECK_VARIABLE_PROPERTY_REVISION, 73 VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY, 74 VARIABLE_ATTRIBUTE_NV_BS_RT_AT, 75 sizeof (UINT8), 76 sizeof (UINT8) 77 } 78 }, 79 { 80 &gEfiAuthenticatedVariableGuid, 81 AUTHVAR_KEYDB_NAME, 82 { 83 VAR_CHECK_VARIABLE_PROPERTY_REVISION, 84 VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY, 85 VARIABLE_ATTRIBUTE_NV_BS_RT_AW, 86 sizeof (UINT8), 87 MAX_UINTN 88 } 89 }, 90 { 91 &gEfiCertDbGuid, 92 EFI_CERT_DB_NAME, 93 { 94 VAR_CHECK_VARIABLE_PROPERTY_REVISION, 95 VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY, 96 VARIABLE_ATTRIBUTE_NV_BS_RT_AT, 97 sizeof (UINT32), 98 MAX_UINTN 99 } 100 }, 101 { 102 &gEdkiiSecureBootModeGuid, 103 L"SecureBootMode", 104 { 105 VAR_CHECK_VARIABLE_PROPERTY_REVISION, 106 VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY, 107 VARIABLE_ATTRIBUTE_NV_BS_RT, 108 sizeof (UINT8), 109 sizeof (UINT8) 110 } 111 } 112 }; 113 114 VOID **mAuthVarAddressPointer[10]; 115 116 AUTH_VAR_LIB_CONTEXT_IN *mAuthVarLibContextIn = NULL; 117 118 /** 119 Initialization for authenticated varibale services. 120 If this initialization returns error status, other APIs will not work 121 and expect to be not called then. 122 123 @param[in] AuthVarLibContextIn Pointer to input auth variable lib context. 124 @param[out] AuthVarLibContextOut Pointer to output auth variable lib context. 125 126 @retval EFI_SUCCESS Function successfully executed. 127 @retval EFI_INVALID_PARAMETER If AuthVarLibContextIn == NULL or AuthVarLibContextOut == NULL. 128 @retval EFI_OUT_OF_RESOURCES Fail to allocate enough resource. 129 @retval EFI_UNSUPPORTED Unsupported to process authenticated variable. 130 131 **/ 132 EFI_STATUS 133 EFIAPI 134 AuthVariableLibInitialize ( 135 IN AUTH_VAR_LIB_CONTEXT_IN *AuthVarLibContextIn, 136 OUT AUTH_VAR_LIB_CONTEXT_OUT *AuthVarLibContextOut 137 ) 138 { 139 EFI_STATUS Status; 140 UINT8 VarValue; 141 UINT32 VarAttr; 142 UINT8 *Data; 143 UINTN DataSize; 144 UINTN CtxSize; 145 UINT8 CustomMode; 146 UINT32 ListSize; 147 148 if ((AuthVarLibContextIn == NULL) || (AuthVarLibContextOut == NULL)) { 149 return EFI_INVALID_PARAMETER; 150 } 151 152 mAuthVarLibContextIn = AuthVarLibContextIn; 153 154 // 155 // Initialize hash context. 156 // 157 CtxSize = Sha256GetContextSize (); 158 mHashCtx = AllocateRuntimePool (CtxSize); 159 if (mHashCtx == NULL) { 160 return EFI_OUT_OF_RESOURCES; 161 } 162 163 // 164 // Reserve runtime buffer for public key database. The size excludes variable header and name size. 165 // 166 mMaxKeyDbSize = (UINT32) (mAuthVarLibContextIn->MaxAuthVariableSize - sizeof (AUTHVAR_KEYDB_NAME)); 167 mMaxKeyNumber = mMaxKeyDbSize / sizeof (AUTHVAR_KEY_DB_DATA); 168 mPubKeyStore = AllocateRuntimePool (mMaxKeyDbSize); 169 if (mPubKeyStore == NULL) { 170 return EFI_OUT_OF_RESOURCES; 171 } 172 173 // 174 // Reserve runtime buffer for certificate database. The size excludes variable header and name size. 175 // 176 mMaxCertDbSize = (UINT32) (mAuthVarLibContextIn->MaxAuthVariableSize - sizeof (EFI_CERT_DB_NAME)); 177 mCertDbStore = AllocateRuntimePool (mMaxCertDbSize); 178 if (mCertDbStore == NULL) { 179 return EFI_OUT_OF_RESOURCES; 180 } 181 182 // 183 // Check "AuthVarKeyDatabase" variable's existence. 184 // If it doesn't exist, create a new one with initial value of 0 and EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS set. 185 // 186 Status = AuthServiceInternalFindVariable ( 187 AUTHVAR_KEYDB_NAME, 188 &gEfiAuthenticatedVariableGuid, 189 (VOID **) &Data, 190 &DataSize 191 ); 192 if (EFI_ERROR (Status)) { 193 VarAttr = EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS; 194 VarValue = 0; 195 mPubKeyNumber = 0; 196 Status = AuthServiceInternalUpdateVariable ( 197 AUTHVAR_KEYDB_NAME, 198 &gEfiAuthenticatedVariableGuid, 199 &VarValue, 200 sizeof(UINT8), 201 VarAttr 202 ); 203 if (EFI_ERROR (Status)) { 204 return Status; 205 } 206 } else { 207 // 208 // Load database in global variable for cache. 209 // 210 ASSERT ((DataSize != 0) && (Data != NULL)); 211 // 212 // "AuthVarKeyDatabase" is an internal variable. Its DataSize is always ensured not to exceed mPubKeyStore buffer size(See definition before) 213 // Therefore, there is no memory overflow in underlying CopyMem. 214 // 215 CopyMem (mPubKeyStore, (UINT8 *) Data, DataSize); 216 mPubKeyNumber = (UINT32) (DataSize / sizeof (AUTHVAR_KEY_DB_DATA)); 217 } 218 219 // 220 // Init Secure Boot variables 221 // 222 Status = InitSecureBootVariables (); 223 224 225 // 226 // Create "SignatureSupport" variable with BS+RT attribute set. 227 // 228 Status = AuthServiceInternalUpdateVariable ( 229 EFI_SIGNATURE_SUPPORT_NAME, 230 &gEfiGlobalVariableGuid, 231 mSignatureSupport, 232 sizeof(mSignatureSupport), 233 EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS 234 ); 235 if (EFI_ERROR (Status)) { 236 return Status; 237 } 238 239 // 240 // Initialize "CustomMode" in STANDARD_SECURE_BOOT_MODE state. 241 // 242 CustomMode = STANDARD_SECURE_BOOT_MODE; 243 Status = AuthServiceInternalUpdateVariable ( 244 EFI_CUSTOM_MODE_NAME, 245 &gEfiCustomModeEnableGuid, 246 &CustomMode, 247 sizeof (UINT8), 248 EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS 249 ); 250 if (EFI_ERROR (Status)) { 251 return Status; 252 } 253 254 DEBUG ((EFI_D_INFO, "Variable %s is %x\n", EFI_CUSTOM_MODE_NAME, CustomMode)); 255 256 // 257 // Check "certdb" variable's existence. 258 // If it doesn't exist, then create a new one with 259 // EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS set. 260 // 261 Status = AuthServiceInternalFindVariable ( 262 EFI_CERT_DB_NAME, 263 &gEfiCertDbGuid, 264 (VOID **) &Data, 265 &DataSize 266 ); 267 if (EFI_ERROR (Status)) { 268 VarAttr = EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS; 269 ListSize = sizeof (UINT32); 270 Status = AuthServiceInternalUpdateVariable ( 271 EFI_CERT_DB_NAME, 272 &gEfiCertDbGuid, 273 &ListSize, 274 sizeof (UINT32), 275 VarAttr 276 ); 277 if (EFI_ERROR (Status)) { 278 return Status; 279 } 280 } else { 281 // 282 // Clean up Certs to make certDB & Time based auth variable consistent 283 // 284 Status = CleanCertsFromDb(); 285 if (EFI_ERROR (Status)) { 286 DEBUG ((EFI_D_ERROR, "Clean up CertDB fail! Status %x\n", Status)); 287 return Status; 288 } 289 } 290 291 // 292 // Check "VendorKeysNv" variable's existence and create "VendorKeys" variable accordingly. 293 // 294 Status = AuthServiceInternalFindVariable (EFI_VENDOR_KEYS_NV_VARIABLE_NAME, &gEfiVendorKeysNvGuid, (VOID **) &Data, &DataSize); 295 if (!EFI_ERROR (Status)) { 296 mVendorKeyState = *(UINT8 *)Data; 297 } else { 298 // 299 // "VendorKeysNv" not exist, initialize it in VENDOR_KEYS_VALID state. 300 // 301 mVendorKeyState = VENDOR_KEYS_VALID; 302 Status = AuthServiceInternalUpdateVariable ( 303 EFI_VENDOR_KEYS_NV_VARIABLE_NAME, 304 &gEfiVendorKeysNvGuid, 305 &mVendorKeyState, 306 sizeof (UINT8), 307 EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS 308 ); 309 if (EFI_ERROR (Status)) { 310 return Status; 311 } 312 } 313 314 // 315 // Create "VendorKeys" variable with BS+RT attribute set. 316 // 317 Status = AuthServiceInternalUpdateVariable ( 318 EFI_VENDOR_KEYS_VARIABLE_NAME, 319 &gEfiGlobalVariableGuid, 320 &mVendorKeyState, 321 sizeof (UINT8), 322 EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS 323 ); 324 if (EFI_ERROR (Status)) { 325 return Status; 326 } 327 328 DEBUG ((EFI_D_INFO, "Variable %s is %x\n", EFI_VENDOR_KEYS_VARIABLE_NAME, mVendorKeyState)); 329 330 AuthVarLibContextOut->StructVersion = AUTH_VAR_LIB_CONTEXT_OUT_STRUCT_VERSION; 331 AuthVarLibContextOut->StructSize = sizeof (AUTH_VAR_LIB_CONTEXT_OUT); 332 AuthVarLibContextOut->AuthVarEntry = mAuthVarEntry; 333 AuthVarLibContextOut->AuthVarEntryCount = sizeof (mAuthVarEntry) / sizeof (mAuthVarEntry[0]); 334 mAuthVarAddressPointer[0] = (VOID **) &mPubKeyStore; 335 mAuthVarAddressPointer[1] = (VOID **) &mCertDbStore; 336 mAuthVarAddressPointer[2] = (VOID **) &mHashCtx; 337 mAuthVarAddressPointer[3] = (VOID **) &mAuthVarLibContextIn; 338 mAuthVarAddressPointer[4] = (VOID **) &(mAuthVarLibContextIn->FindVariable), 339 mAuthVarAddressPointer[5] = (VOID **) &(mAuthVarLibContextIn->FindNextVariable), 340 mAuthVarAddressPointer[6] = (VOID **) &(mAuthVarLibContextIn->UpdateVariable), 341 mAuthVarAddressPointer[7] = (VOID **) &(mAuthVarLibContextIn->GetScratchBuffer), 342 mAuthVarAddressPointer[8] = (VOID **) &(mAuthVarLibContextIn->CheckRemainingSpaceForConsistency), 343 mAuthVarAddressPointer[9] = (VOID **) &(mAuthVarLibContextIn->AtRuntime), 344 AuthVarLibContextOut->AddressPointer = mAuthVarAddressPointer; 345 AuthVarLibContextOut->AddressPointerCount = sizeof (mAuthVarAddressPointer) / sizeof (mAuthVarAddressPointer[0]); 346 347 return Status; 348 } 349 350 /** 351 Process variable with EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS/EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS set. 352 353 @param[in] VariableName Name of the variable. 354 @param[in] VendorGuid Variable vendor GUID. 355 @param[in] Data Data pointer. 356 @param[in] DataSize Size of Data. 357 @param[in] Attributes Attribute value of the variable. 358 359 @retval EFI_SUCCESS The firmware has successfully stored the variable and its data as 360 defined by the Attributes. 361 @retval EFI_INVALID_PARAMETER Invalid parameter. 362 @retval EFI_WRITE_PROTECTED Variable is write-protected. 363 @retval EFI_OUT_OF_RESOURCES There is not enough resource. 364 @retval EFI_SECURITY_VIOLATION The variable is with EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS 365 or EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACESS 366 set, but the AuthInfo does NOT pass the validation 367 check carried out by the firmware. 368 @retval EFI_UNSUPPORTED Unsupported to process authenticated variable. 369 370 **/ 371 EFI_STATUS 372 EFIAPI 373 AuthVariableLibProcessVariable ( 374 IN CHAR16 *VariableName, 375 IN EFI_GUID *VendorGuid, 376 IN VOID *Data, 377 IN UINTN DataSize, 378 IN UINT32 Attributes 379 ) 380 { 381 EFI_STATUS Status; 382 383 // 384 // Process PK, KEK, Sigdb, AuditMode, DeployedMode separately. 385 // 386 if (CompareGuid (VendorGuid, &gEfiGlobalVariableGuid) && (StrCmp (VariableName, EFI_PLATFORM_KEY_NAME) == 0)){ 387 Status = ProcessVarWithPk (VariableName, VendorGuid, Data, DataSize, Attributes, TRUE); 388 } else if (CompareGuid (VendorGuid, &gEfiGlobalVariableGuid) && (StrCmp (VariableName, EFI_KEY_EXCHANGE_KEY_NAME) == 0)) { 389 Status = ProcessVarWithPk (VariableName, VendorGuid, Data, DataSize, Attributes, FALSE); 390 } else if (CompareGuid (VendorGuid, &gEfiGlobalVariableGuid) 391 && (StrCmp (VariableName, EFI_AUDIT_MODE_NAME) == 0 || StrCmp (VariableName, EFI_DEPLOYED_MODE_NAME) == 0)) { 392 Status = ProcessSecureBootModeVar(VariableName, VendorGuid, Data, DataSize, Attributes); 393 } else if (CompareGuid (VendorGuid, &gEfiImageSecurityDatabaseGuid) && 394 ((StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE) == 0) || 395 (StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE1) == 0) || 396 (StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE2) == 0) 397 )) { 398 Status = ProcessVarWithPk (VariableName, VendorGuid, Data, DataSize, Attributes, FALSE); 399 if (EFI_ERROR (Status)) { 400 Status = ProcessVarWithKek (VariableName, VendorGuid, Data, DataSize, Attributes); 401 } 402 } else { 403 Status = ProcessVariable (VariableName, VendorGuid, Data, DataSize, Attributes); 404 } 405 406 return Status; 407 } 408
