2 Measure TCG required variable.
4 Copyright (c) 2013 - 2017, Intel Corporation. All rights reserved.<BR>
5 This program and the accompanying materials
6 are licensed and made available under the terms and conditions of the BSD License
7 which accompanies this distribution. The full text of the license may be found at
8 http://opensource.org/licenses/bsd-license.php
10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
16 #include <Guid/ImageAuthentication.h>
17 #include <IndustryStandard/UefiTcgPlatform.h>
19 #include <Library/UefiBootServicesTableLib.h>
20 #include <Library/UefiRuntimeServicesTableLib.h>
21 #include <Library/MemoryAllocationLib.h>
22 #include <Library/BaseMemoryLib.h>
23 #include <Library/DebugLib.h>
24 #include <Library/BaseLib.h>
25 #include <Library/TpmMeasurementLib.h>
32 VARIABLE_TYPE mVariableType
[] = {
33 {EFI_SECURE_BOOT_MODE_NAME
, &gEfiGlobalVariableGuid
},
34 {EFI_PLATFORM_KEY_NAME
, &gEfiGlobalVariableGuid
},
35 {EFI_KEY_EXCHANGE_KEY_NAME
, &gEfiGlobalVariableGuid
},
36 {EFI_IMAGE_SECURITY_DATABASE
, &gEfiImageSecurityDatabaseGuid
},
37 {EFI_IMAGE_SECURITY_DATABASE1
, &gEfiImageSecurityDatabaseGuid
},
38 {EFI_IMAGE_SECURITY_DATABASE2
, &gEfiImageSecurityDatabaseGuid
},
42 // "SecureBoot" may update following PK Del/Add
43 // Cache its value to detect value update
45 UINT8
*mSecureBootVarData
= NULL
;
46 UINTN mSecureBootVarDataSize
= 0;
49 This function will return if this variable is SecureBootPolicy Variable.
51 @param[in] VariableName A Null-terminated string that is the name of the vendor's variable.
52 @param[in] VendorGuid A unique identifier for the vendor.
54 @retval TRUE This is SecureBootPolicy Variable
55 @retval FALSE This is not SecureBootPolicy Variable
58 IsSecureBootPolicyVariable (
59 IN CHAR16
*VariableName
,
60 IN EFI_GUID
*VendorGuid
65 for (Index
= 0; Index
< sizeof(mVariableType
)/sizeof(mVariableType
[0]); Index
++) {
66 if ((StrCmp (VariableName
, mVariableType
[Index
].VariableName
) == 0) &&
67 (CompareGuid (VendorGuid
, mVariableType
[Index
].VendorGuid
))) {
75 Measure and log an EFI variable, and extend the measurement result into a specific PCR.
77 @param[in] VarName A Null-terminated string that is the name of the vendor's variable.
78 @param[in] VendorGuid A unique identifier for the vendor.
79 @param[in] VarData The content of the variable data.
80 @param[in] VarSize The size of the variable data.
82 @retval EFI_SUCCESS Operation completed successfully.
83 @retval EFI_OUT_OF_RESOURCES Out of memory.
84 @retval EFI_DEVICE_ERROR The operation was unsuccessful.
91 IN EFI_GUID
*VendorGuid
,
98 UEFI_VARIABLE_DATA
*VarLog
;
101 ASSERT ((VarSize
== 0 && VarData
== NULL
) || (VarSize
!= 0 && VarData
!= NULL
));
103 VarNameLength
= StrLen (VarName
);
104 VarLogSize
= (UINT32
)(sizeof (*VarLog
) + VarNameLength
* sizeof (*VarName
) + VarSize
105 - sizeof (VarLog
->UnicodeName
) - sizeof (VarLog
->VariableData
));
107 VarLog
= (UEFI_VARIABLE_DATA
*) AllocateZeroPool (VarLogSize
);
108 if (VarLog
== NULL
) {
109 return EFI_OUT_OF_RESOURCES
;
112 CopyMem (&VarLog
->VariableName
, VendorGuid
, sizeof(VarLog
->VariableName
));
113 VarLog
->UnicodeNameLength
= VarNameLength
;
114 VarLog
->VariableDataLength
= VarSize
;
118 VarNameLength
* sizeof (*VarName
)
122 (CHAR16
*)VarLog
->UnicodeName
+ VarNameLength
,
128 DEBUG ((EFI_D_INFO
, "AuthVariableDxe: MeasureVariable (Pcr - %x, EventType - %x, ", (UINTN
)7, (UINTN
)EV_EFI_VARIABLE_AUTHORITY
));
129 DEBUG ((EFI_D_INFO
, "VariableName - %s, VendorGuid - %g)\n", VarName
, VendorGuid
));
131 Status
= TpmMeasureAndLogData (
133 EV_EFI_VARIABLE_DRIVER_CONFIG
,
144 Returns the status whether get the variable success. The function retrieves
145 variable through the UEFI Runtime Service GetVariable(). The
146 returned buffer is allocated using AllocatePool(). The caller is responsible
147 for freeing this buffer with FreePool().
149 This API is only invoked in boot time. It may NOT be invoked at runtime.
151 @param[in] Name The pointer to a Null-terminated Unicode string.
152 @param[in] Guid The pointer to an EFI_GUID structure
153 @param[out] Value The buffer point saved the variable info.
154 @param[out] Size The buffer size of the variable.
156 @return EFI_OUT_OF_RESOURCES Allocate buffer failed.
157 @return EFI_SUCCESS Find the specified variable.
158 @return Others Errors Return errors from call to gRT->GetVariable.
162 InternalGetVariable (
163 IN CONST CHAR16
*Name
,
164 IN CONST EFI_GUID
*Guid
,
173 // Try to get the variable size.
181 Status
= gRT
->GetVariable ((CHAR16
*) Name
, (EFI_GUID
*) Guid
, NULL
, &BufferSize
, *Value
);
182 if (Status
!= EFI_BUFFER_TOO_SMALL
) {
187 // Allocate buffer to get the variable.
189 *Value
= AllocatePool (BufferSize
);
190 ASSERT (*Value
!= NULL
);
191 if (*Value
== NULL
) {
192 return EFI_OUT_OF_RESOURCES
;
196 // Get the variable data.
198 Status
= gRT
->GetVariable ((CHAR16
*) Name
, (EFI_GUID
*) Guid
, NULL
, &BufferSize
, *Value
);
199 if (EFI_ERROR (Status
)) {
212 SecureBoot Hook for SetVariable.
214 @param[in] VariableName Name of Variable to be found.
215 @param[in] VendorGuid Variable vendor GUID.
221 IN CHAR16
*VariableName
,
222 IN EFI_GUID
*VendorGuid
226 UINTN VariableDataSize
;
229 if (!IsSecureBootPolicyVariable (VariableName
, VendorGuid
)) {
234 // We should NOT use Data and DataSize here,because it may include signature,
235 // or is just partial with append attributes, or is deleted.
236 // We should GetVariable again, to get full variable content.
238 Status
= InternalGetVariable (
244 if (EFI_ERROR (Status
)) {
246 // Measure DBT only if present and not empty
248 if (StrCmp (VariableName
, EFI_IMAGE_SECURITY_DATABASE2
) == 0 &&
249 CompareGuid (VendorGuid
, &gEfiImageSecurityDatabaseGuid
)) {
250 DEBUG((DEBUG_INFO
, "Skip measuring variable %s since it's deleted\n", EFI_IMAGE_SECURITY_DATABASE2
));
254 VariableDataSize
= 0;
258 Status
= MeasureVariable (
264 DEBUG ((EFI_D_INFO
, "MeasureBootPolicyVariable - %r\n", Status
));
266 if (VariableData
!= NULL
) {
267 FreePool (VariableData
);
271 // "SecureBoot" is 8bit & read-only. It can only be changed according to PK update
273 if ((StrCmp (VariableName
, EFI_PLATFORM_KEY_NAME
) == 0) &&
274 CompareGuid (VendorGuid
, &gEfiGlobalVariableGuid
)) {
275 Status
= InternalGetVariable (
276 EFI_SECURE_BOOT_MODE_NAME
,
277 &gEfiGlobalVariableGuid
,
281 if (EFI_ERROR (Status
)) {
286 // If PK update is successful. "SecureBoot" shall always exist ever since variable write service is ready
288 ASSERT(mSecureBootVarData
!= NULL
);
290 if (CompareMem(mSecureBootVarData
, VariableData
, VariableDataSize
) != 0) {
291 FreePool(mSecureBootVarData
);
292 mSecureBootVarData
= VariableData
;
293 mSecureBootVarDataSize
= VariableDataSize
;
295 DEBUG((DEBUG_INFO
, "%s variable updated according to PK change. Remeasure the value!\n", EFI_SECURE_BOOT_MODE_NAME
));
296 Status
= MeasureVariable (
297 EFI_SECURE_BOOT_MODE_NAME
,
298 &gEfiGlobalVariableGuid
,
300 mSecureBootVarDataSize
302 DEBUG ((DEBUG_INFO
, "MeasureBootPolicyVariable - %r\n", Status
));
305 // "SecureBoot" variable is not changed
307 FreePool(VariableData
);
315 Some Secure Boot Policy Variable may update following other variable changes(SecureBoot follows PK change, etc).
316 Record their initial State when variable write service is ready.
321 RecordSecureBootPolicyVarData(
328 // Record initial "SecureBoot" variable value.
329 // It is used to detect SecureBoot variable change in SecureBootHook.
331 Status
= InternalGetVariable (
332 EFI_SECURE_BOOT_MODE_NAME
,
333 &gEfiGlobalVariableGuid
,
334 (VOID
**)&mSecureBootVarData
,
335 &mSecureBootVarDataSize
337 if (EFI_ERROR(Status
)) {
339 // Read could fail when Auth Variable solution is not supported
341 DEBUG((DEBUG_INFO
, "RecordSecureBootPolicyVarData GetVariable %s Status %x\n", EFI_SECURE_BOOT_MODE_NAME
, Status
));