2 Implement authentication services for the authenticated variables.
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.
14 Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.<BR>
15 SPDX-License-Identifier: BSD-2-Clause-Patent
19 #include "AuthServiceInternal.h"
22 /// Global database array for scratch
25 UINT32 mMaxCertDbSize
;
27 UINT8 mVendorKeyState
;
29 EFI_GUID mSignatureSupport
[] = { EFI_CERT_SHA1_GUID
, EFI_CERT_SHA256_GUID
, EFI_CERT_RSA2048_GUID
, EFI_CERT_X509_GUID
};
32 // Hash context pointer
34 VOID
*mHashCtx
= NULL
;
36 VARIABLE_ENTRY_PROPERTY mAuthVarEntry
[] = {
38 &gEfiSecureBootEnableDisableGuid
,
39 EFI_SECURE_BOOT_ENABLE_NAME
,
41 VAR_CHECK_VARIABLE_PROPERTY_REVISION
,
43 VARIABLE_ATTRIBUTE_NV_BS
,
49 &gEfiCustomModeEnableGuid
,
52 VAR_CHECK_VARIABLE_PROPERTY_REVISION
,
54 VARIABLE_ATTRIBUTE_NV_BS
,
60 &gEfiVendorKeysNvGuid
,
61 EFI_VENDOR_KEYS_NV_VARIABLE_NAME
,
63 VAR_CHECK_VARIABLE_PROPERTY_REVISION
,
64 VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY
,
65 VARIABLE_ATTRIBUTE_NV_BS_RT_AT
,
74 VAR_CHECK_VARIABLE_PROPERTY_REVISION
,
75 VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY
,
76 VARIABLE_ATTRIBUTE_NV_BS_RT_AT
,
83 EFI_CERT_DB_VOLATILE_NAME
,
85 VAR_CHECK_VARIABLE_PROPERTY_REVISION
,
86 VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY
,
87 VARIABLE_ATTRIBUTE_BS_RT_AT
,
94 VOID
**mAuthVarAddressPointer
[9];
96 AUTH_VAR_LIB_CONTEXT_IN
*mAuthVarLibContextIn
= NULL
;
99 Initialization for authenticated variable services.
100 If this initialization returns error status, other APIs will not work
101 and expect to be not called then.
103 @param[in] AuthVarLibContextIn Pointer to input auth variable lib context.
104 @param[out] AuthVarLibContextOut Pointer to output auth variable lib context.
106 @retval EFI_SUCCESS Function successfully executed.
107 @retval EFI_INVALID_PARAMETER If AuthVarLibContextIn == NULL or AuthVarLibContextOut == NULL.
108 @retval EFI_OUT_OF_RESOURCES Fail to allocate enough resource.
109 @retval EFI_UNSUPPORTED Unsupported to process authenticated variable.
114 AuthVariableLibInitialize (
115 IN AUTH_VAR_LIB_CONTEXT_IN
*AuthVarLibContextIn
,
116 OUT AUTH_VAR_LIB_CONTEXT_OUT
*AuthVarLibContextOut
124 UINT8 SecureBootMode
;
125 UINT8 SecureBootEnable
;
129 if ((AuthVarLibContextIn
== NULL
) || (AuthVarLibContextOut
== NULL
)) {
130 return EFI_INVALID_PARAMETER
;
133 mAuthVarLibContextIn
= AuthVarLibContextIn
;
136 // Initialize hash context.
138 CtxSize
= Sha256GetContextSize ();
139 mHashCtx
= AllocateRuntimePool (CtxSize
);
140 if (mHashCtx
== NULL
) {
141 return EFI_OUT_OF_RESOURCES
;
145 // Reserve runtime buffer for certificate database. The size excludes variable header and name size.
146 // Use EFI_CERT_DB_VOLATILE_NAME size since it is longer.
148 mMaxCertDbSize
= (UINT32
)(mAuthVarLibContextIn
->MaxAuthVariableSize
- sizeof (EFI_CERT_DB_VOLATILE_NAME
));
149 mCertDbStore
= AllocateRuntimePool (mMaxCertDbSize
);
150 if (mCertDbStore
== NULL
) {
151 return EFI_OUT_OF_RESOURCES
;
154 Status
= AuthServiceInternalFindVariable (EFI_PLATFORM_KEY_NAME
, &gEfiGlobalVariableGuid
, (VOID
**)&Data
, &DataSize
);
155 if (EFI_ERROR (Status
)) {
156 DEBUG ((DEBUG_INFO
, "Variable %s does not exist.\n", EFI_PLATFORM_KEY_NAME
));
158 DEBUG ((DEBUG_INFO
, "Variable %s exists.\n", EFI_PLATFORM_KEY_NAME
));
162 // Create "SetupMode" variable with BS+RT attribute set.
164 if (EFI_ERROR (Status
)) {
165 mPlatformMode
= SETUP_MODE
;
167 mPlatformMode
= USER_MODE
;
170 Status
= AuthServiceInternalUpdateVariable (
172 &gEfiGlobalVariableGuid
,
175 EFI_VARIABLE_BOOTSERVICE_ACCESS
| EFI_VARIABLE_RUNTIME_ACCESS
177 if (EFI_ERROR (Status
)) {
182 // Create "SignatureSupport" variable with BS+RT attribute set.
184 Status
= AuthServiceInternalUpdateVariable (
185 EFI_SIGNATURE_SUPPORT_NAME
,
186 &gEfiGlobalVariableGuid
,
188 sizeof (mSignatureSupport
),
189 EFI_VARIABLE_BOOTSERVICE_ACCESS
| EFI_VARIABLE_RUNTIME_ACCESS
191 if (EFI_ERROR (Status
)) {
196 // If "SecureBootEnable" variable exists, then update "SecureBoot" variable.
197 // If "SecureBootEnable" variable is SECURE_BOOT_ENABLE and in USER_MODE, Set "SecureBoot" variable to SECURE_BOOT_MODE_ENABLE.
198 // If "SecureBootEnable" variable is SECURE_BOOT_DISABLE, Set "SecureBoot" variable to SECURE_BOOT_MODE_DISABLE.
200 SecureBootEnable
= SECURE_BOOT_DISABLE
;
201 Status
= AuthServiceInternalFindVariable (EFI_SECURE_BOOT_ENABLE_NAME
, &gEfiSecureBootEnableDisableGuid
, (VOID
**)&Data
, &DataSize
);
202 if (!EFI_ERROR (Status
)) {
203 if (mPlatformMode
== USER_MODE
) {
204 SecureBootEnable
= *(UINT8
*)Data
;
206 } else if (mPlatformMode
== USER_MODE
) {
208 // "SecureBootEnable" not exist, initialize it in USER_MODE.
210 SecureBootEnable
= SECURE_BOOT_ENABLE
;
211 Status
= AuthServiceInternalUpdateVariable (
212 EFI_SECURE_BOOT_ENABLE_NAME
,
213 &gEfiSecureBootEnableDisableGuid
,
216 EFI_VARIABLE_NON_VOLATILE
| EFI_VARIABLE_BOOTSERVICE_ACCESS
218 if (EFI_ERROR (Status
)) {
224 // Create "SecureBoot" variable with BS+RT attribute set.
226 if ((SecureBootEnable
== SECURE_BOOT_ENABLE
) && (mPlatformMode
== USER_MODE
)) {
227 SecureBootMode
= SECURE_BOOT_MODE_ENABLE
;
229 SecureBootMode
= SECURE_BOOT_MODE_DISABLE
;
232 Status
= AuthServiceInternalUpdateVariable (
233 EFI_SECURE_BOOT_MODE_NAME
,
234 &gEfiGlobalVariableGuid
,
237 EFI_VARIABLE_RUNTIME_ACCESS
| EFI_VARIABLE_BOOTSERVICE_ACCESS
239 if (EFI_ERROR (Status
)) {
243 DEBUG ((DEBUG_INFO
, "Variable %s is %x\n", EFI_SETUP_MODE_NAME
, mPlatformMode
));
244 DEBUG ((DEBUG_INFO
, "Variable %s is %x\n", EFI_SECURE_BOOT_MODE_NAME
, SecureBootMode
));
245 DEBUG ((DEBUG_INFO
, "Variable %s is %x\n", EFI_SECURE_BOOT_ENABLE_NAME
, SecureBootEnable
));
248 // Initialize "CustomMode" in STANDARD_SECURE_BOOT_MODE state.
250 CustomMode
= STANDARD_SECURE_BOOT_MODE
;
251 Status
= AuthServiceInternalUpdateVariable (
252 EFI_CUSTOM_MODE_NAME
,
253 &gEfiCustomModeEnableGuid
,
256 EFI_VARIABLE_NON_VOLATILE
| EFI_VARIABLE_BOOTSERVICE_ACCESS
258 if (EFI_ERROR (Status
)) {
262 DEBUG ((DEBUG_INFO
, "Variable %s is %x\n", EFI_CUSTOM_MODE_NAME
, CustomMode
));
265 // Check "certdb" variable's existence.
266 // If it doesn't exist, then create a new one with
267 // EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS set.
269 Status
= AuthServiceInternalFindVariable (
275 if (EFI_ERROR (Status
)) {
276 VarAttr
= EFI_VARIABLE_NON_VOLATILE
| EFI_VARIABLE_RUNTIME_ACCESS
| EFI_VARIABLE_BOOTSERVICE_ACCESS
| EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS
;
277 ListSize
= sizeof (UINT32
);
278 Status
= AuthServiceInternalUpdateVariable (
285 if (EFI_ERROR (Status
)) {
290 // Clean up Certs to make certDB & Time based auth variable consistent
292 Status
= CleanCertsFromDb ();
293 if (EFI_ERROR (Status
)) {
294 DEBUG ((DEBUG_ERROR
, "Clean up CertDB fail! Status %x\n", Status
));
300 // Create "certdbv" variable with RT+BS+AT set.
302 VarAttr
= EFI_VARIABLE_RUNTIME_ACCESS
| EFI_VARIABLE_BOOTSERVICE_ACCESS
| EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS
;
303 ListSize
= sizeof (UINT32
);
304 Status
= AuthServiceInternalUpdateVariable (
305 EFI_CERT_DB_VOLATILE_NAME
,
311 if (EFI_ERROR (Status
)) {
316 // Check "VendorKeysNv" variable's existence and create "VendorKeys" variable accordingly.
318 Status
= AuthServiceInternalFindVariable (EFI_VENDOR_KEYS_NV_VARIABLE_NAME
, &gEfiVendorKeysNvGuid
, (VOID
**)&Data
, &DataSize
);
319 if (!EFI_ERROR (Status
)) {
320 mVendorKeyState
= *(UINT8
*)Data
;
323 // "VendorKeysNv" not exist, initialize it in VENDOR_KEYS_VALID state.
325 mVendorKeyState
= VENDOR_KEYS_VALID
;
326 Status
= AuthServiceInternalUpdateVariable (
327 EFI_VENDOR_KEYS_NV_VARIABLE_NAME
,
328 &gEfiVendorKeysNvGuid
,
331 EFI_VARIABLE_NON_VOLATILE
| EFI_VARIABLE_BOOTSERVICE_ACCESS
| EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS
333 if (EFI_ERROR (Status
)) {
339 // Create "VendorKeys" variable with BS+RT attribute set.
341 Status
= AuthServiceInternalUpdateVariable (
342 EFI_VENDOR_KEYS_VARIABLE_NAME
,
343 &gEfiGlobalVariableGuid
,
346 EFI_VARIABLE_RUNTIME_ACCESS
| EFI_VARIABLE_BOOTSERVICE_ACCESS
348 if (EFI_ERROR (Status
)) {
352 DEBUG ((DEBUG_INFO
, "Variable %s is %x\n", EFI_VENDOR_KEYS_VARIABLE_NAME
, mVendorKeyState
));
354 AuthVarLibContextOut
->StructVersion
= AUTH_VAR_LIB_CONTEXT_OUT_STRUCT_VERSION
;
355 AuthVarLibContextOut
->StructSize
= sizeof (AUTH_VAR_LIB_CONTEXT_OUT
);
356 AuthVarLibContextOut
->AuthVarEntry
= mAuthVarEntry
;
357 AuthVarLibContextOut
->AuthVarEntryCount
= ARRAY_SIZE (mAuthVarEntry
);
358 mAuthVarAddressPointer
[0] = (VOID
**)&mCertDbStore
;
359 mAuthVarAddressPointer
[1] = (VOID
**)&mHashCtx
;
360 mAuthVarAddressPointer
[2] = (VOID
**)&mAuthVarLibContextIn
;
361 mAuthVarAddressPointer
[3] = (VOID
**)&(mAuthVarLibContextIn
->FindVariable
),
362 mAuthVarAddressPointer
[4] = (VOID
**)&(mAuthVarLibContextIn
->FindNextVariable
),
363 mAuthVarAddressPointer
[5] = (VOID
**)&(mAuthVarLibContextIn
->UpdateVariable
),
364 mAuthVarAddressPointer
[6] = (VOID
**)&(mAuthVarLibContextIn
->GetScratchBuffer
),
365 mAuthVarAddressPointer
[7] = (VOID
**)&(mAuthVarLibContextIn
->CheckRemainingSpaceForConsistency
),
366 mAuthVarAddressPointer
[8] = (VOID
**)&(mAuthVarLibContextIn
->AtRuntime
),
367 AuthVarLibContextOut
->AddressPointer
= mAuthVarAddressPointer
;
368 AuthVarLibContextOut
->AddressPointerCount
= ARRAY_SIZE (mAuthVarAddressPointer
);
374 Process variable with EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS set.
376 @param[in] VariableName Name of the variable.
377 @param[in] VendorGuid Variable vendor GUID.
378 @param[in] Data Data pointer.
379 @param[in] DataSize Size of Data.
380 @param[in] Attributes Attribute value of the variable.
382 @retval EFI_SUCCESS The firmware has successfully stored the variable and its data as
383 defined by the Attributes.
384 @retval EFI_INVALID_PARAMETER Invalid parameter.
385 @retval EFI_WRITE_PROTECTED Variable is write-protected.
386 @retval EFI_OUT_OF_RESOURCES There is not enough resource.
387 @retval EFI_SECURITY_VIOLATION The variable is with EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS
388 set, but the AuthInfo does NOT pass the validation
389 check carried out by the firmware.
390 @retval EFI_UNSUPPORTED Unsupported to process authenticated variable.
395 AuthVariableLibProcessVariable (
396 IN CHAR16
*VariableName
,
397 IN EFI_GUID
*VendorGuid
,
405 if (CompareGuid (VendorGuid
, &gEfiGlobalVariableGuid
) && (StrCmp (VariableName
, EFI_PLATFORM_KEY_NAME
) == 0)) {
406 Status
= ProcessVarWithPk (VariableName
, VendorGuid
, Data
, DataSize
, Attributes
, TRUE
);
407 } else if (CompareGuid (VendorGuid
, &gEfiGlobalVariableGuid
) && (StrCmp (VariableName
, EFI_KEY_EXCHANGE_KEY_NAME
) == 0)) {
408 Status
= ProcessVarWithPk (VariableName
, VendorGuid
, Data
, DataSize
, Attributes
, FALSE
);
409 } else if (CompareGuid (VendorGuid
, &gEfiImageSecurityDatabaseGuid
) &&
410 ((StrCmp (VariableName
, EFI_IMAGE_SECURITY_DATABASE
) == 0) ||
411 (StrCmp (VariableName
, EFI_IMAGE_SECURITY_DATABASE1
) == 0) ||
412 (StrCmp (VariableName
, EFI_IMAGE_SECURITY_DATABASE2
) == 0)
415 Status
= ProcessVarWithPk (VariableName
, VendorGuid
, Data
, DataSize
, Attributes
, FALSE
);
416 if (EFI_ERROR (Status
)) {
417 Status
= ProcessVarWithKek (VariableName
, VendorGuid
, Data
, DataSize
, Attributes
);
420 Status
= ProcessVariable (VariableName
, VendorGuid
, Data
, DataSize
, Attributes
);