SecurityPkg/VariableAuthenticated/RuntimeDxe/Variable.h

   1 /** @file
   2   The internal header file includes the common header files, defines
   3   internal structure and functions used by Variable modules.
   4
   5 Copyright (c) 2009 - 2013, Intel Corporation. All rights reserved.<BR>
   6 This program and the accompanying materials
   7 are licensed and made available under the terms and conditions of the BSD License
   8 which accompanies this distribution.  The full text of the license may be found at
   9 http://opensource.org/licenses/bsd-license.php
  10
  11 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13
  14 **/
  15
  16 #ifndef _VARIABLE_H_
  17 #define _VARIABLE_H_
  18
  19 #include <PiDxe.h>
  20 #include <Protocol/VariableWrite.h>
  21 #include <Protocol/FaultTolerantWrite.h>
  22 #include <Protocol/FirmwareVolumeBlock.h>
  23 #include <Protocol/Variable.h>
  24 #include <Protocol/VariableLock.h>
  25 #include <Library/PcdLib.h>
  26 #include <Library/HobLib.h>
  27 #include <Library/UefiDriverEntryPoint.h>
  28 #include <Library/DxeServicesTableLib.h>
  29 #include <Library/UefiRuntimeLib.h>
  30 #include <Library/DebugLib.h>
  31 #include <Library/BaseMemoryLib.h>
  32 #include <Library/UefiBootServicesTableLib.h>
  33 #include <Library/UefiLib.h>
  34 #include <Library/BaseLib.h>
  35 #include <Library/SynchronizationLib.h>
  36 #include <Library/MemoryAllocationLib.h>
  37 #include <Library/BaseCryptLib.h>
  38 #include <Library/PlatformSecureLib.h>
  39 #include <Guid/GlobalVariable.h>
  40 #include <Guid/EventGroup.h>
  41 #include <Guid/AuthenticatedVariableFormat.h>
  42 #include <Guid/ImageAuthentication.h>
  43 #include <Guid/SystemNvDataGuid.h>
  44 #include <Guid/HardwareErrorVariable.h>
  45
  46 #define VARIABLE_RECLAIM_THRESHOLD (1024)
  47 #define EFI_VARIABLE_ATTRIBUTES_MASK (EFI_VARIABLE_NON_VOLATILE | \
  48                                       EFI_VARIABLE_BOOTSERVICE_ACCESS | \
  49                                       EFI_VARIABLE_RUNTIME_ACCESS | \
  50                                       EFI_VARIABLE_HARDWARE_ERROR_RECORD | \
  51                                       EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS | \
  52                                       EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS | \
  53                                       EFI_VARIABLE_APPEND_WRITE)
  54
  55 ///
  56 /// The size of a 3 character ISO639 language code.
  57 ///
  58 #define ISO_639_2_ENTRY_SIZE    3
  59
  60 typedef enum {
  61   VariableStoreTypeVolatile,
  62   VariableStoreTypeHob,
  63   VariableStoreTypeNv,
  64   VariableStoreTypeMax
  65 } VARIABLE_STORE_TYPE;
  66
  67 typedef struct {
  68   VARIABLE_HEADER *CurrPtr;
  69   //
  70   // If both ADDED and IN_DELETED_TRANSITION variable are present,
  71   // InDeletedTransitionPtr will point to the IN_DELETED_TRANSITION one.
  72   // Otherwise, CurrPtr will point to the ADDED or IN_DELETED_TRANSITION one,
  73   // and InDeletedTransitionPtr will be NULL at the same time.
  74   //
  75   VARIABLE_HEADER *InDeletedTransitionPtr;
  76   VARIABLE_HEADER *EndPtr;
  77   VARIABLE_HEADER *StartPtr;
  78   BOOLEAN         Volatile;
  79 } VARIABLE_POINTER_TRACK;
  80
  81 typedef struct {
  82   EFI_PHYSICAL_ADDRESS  HobVariableBase;
  83   EFI_PHYSICAL_ADDRESS  VolatileVariableBase;
  84   EFI_PHYSICAL_ADDRESS  NonVolatileVariableBase;
  85   EFI_LOCK              VariableServicesLock;
  86   UINT32                ReentrantState;
  87 } VARIABLE_GLOBAL;
  88
  89 typedef struct {
  90   VARIABLE_GLOBAL VariableGlobal;
  91   UINTN           VolatileLastVariableOffset;
  92   UINTN           NonVolatileLastVariableOffset;
  93   UINTN           CommonVariableTotalSize;
  94   UINTN           HwErrVariableTotalSize;
  95   CHAR8           *PlatformLangCodes;
  96   CHAR8           *LangCodes;
  97   CHAR8           *PlatformLang;
  98   CHAR8           Lang[ISO_639_2_ENTRY_SIZE + 1];
  99   EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL *FvbInstance;
 100 } VARIABLE_MODULE_GLOBAL;
 101
 102 typedef struct {
 103   EFI_GUID    *Guid;
 104   CHAR16      *Name;
 105   UINT32      Attributes;
 106   UINTN       DataSize;
 107   VOID        *Data;
 108 } VARIABLE_CACHE_ENTRY;
 109
 110 typedef struct {
 111   EFI_GUID    Guid;
 112   CHAR16      *Name;
 113   LIST_ENTRY  Link;
 114 } VARIABLE_ENTRY;
 115
 116 /**
 117   Flush the HOB variable to flash.
 118
 119   @param[in] VariableName       Name of variable has been updated or deleted.
 120   @param[in] VendorGuid         Guid of variable has been updated or deleted.
 121
 122 **/
 123 VOID
 124 FlushHobVariableToFlash (
 125   IN CHAR16                     *VariableName,
 126   IN EFI_GUID                   *VendorGuid
 127   );
 128
 129 /**
 130   Writes a buffer to variable storage space, in the working block.
 131
 132   This function writes a buffer to variable storage space into a firmware
 133   volume block device. The destination is specified by the parameter
 134   VariableBase. Fault Tolerant Write protocol is used for writing.
 135
 136   @param  VariableBase   Base address of the variable to write.
 137   @param  Buffer         Point to the data buffer.
 138   @param  BufferSize     The number of bytes of the data Buffer.
 139
 140   @retval EFI_SUCCESS    The function completed successfully.
 141   @retval EFI_NOT_FOUND  Fail to locate Fault Tolerant Write protocol.
 142   @retval EFI_ABORTED    The function could not complete successfully.
 143
 144 **/
 145 EFI_STATUS
 146 FtwVariableSpace (
 147   IN EFI_PHYSICAL_ADDRESS   VariableBase,
 148   IN UINT8                  *Buffer,
 149   IN UINTN                  BufferSize
 150   );
 151
 152 /**
 153   Finds variable in storage blocks of volatile and non-volatile storage areas.
 154
 155   This code finds variable in storage blocks of volatile and non-volatile storage areas.
 156   If VariableName is an empty string, then we just return the first
 157   qualified variable without comparing VariableName and VendorGuid.
 158   If IgnoreRtCheck is TRUE, then we ignore the EFI_VARIABLE_RUNTIME_ACCESS attribute check
 159   at runtime when searching existing variable, only VariableName and VendorGuid are compared.
 160   Otherwise, variables without EFI_VARIABLE_RUNTIME_ACCESS are not visible at runtime.
 161
 162   @param[in]   VariableName           Name of the variable to be found.
 163   @param[in]   VendorGuid             Vendor GUID to be found.
 164   @param[out]  PtrTrack               VARIABLE_POINTER_TRACK structure for output,
 165                                       including the range searched and the target position.
 166   @param[in]   Global                 Pointer to VARIABLE_GLOBAL structure, including
 167                                       base of volatile variable storage area, base of
 168                                       NV variable storage area, and a lock.
 169   @param[in]   IgnoreRtCheck          Ignore EFI_VARIABLE_RUNTIME_ACCESS attribute
 170                                       check at runtime when searching variable.
 171
 172   @retval EFI_INVALID_PARAMETER       If VariableName is not an empty string, while
 173                                       VendorGuid is NULL.
 174   @retval EFI_SUCCESS                 Variable successfully found.
 175   @retval EFI_NOT_FOUND               Variable not found
 176
 177 **/
 178 EFI_STATUS
 179 FindVariable (
 180   IN  CHAR16                  *VariableName,
 181   IN  EFI_GUID                *VendorGuid,
 182   OUT VARIABLE_POINTER_TRACK  *PtrTrack,
 183   IN  VARIABLE_GLOBAL         *Global,
 184   IN  BOOLEAN                 IgnoreRtCheck
 185   );
 186
 187 /**
 188
 189   This code gets the pointer to the variable data.
 190
 191   @param Variable        Pointer to the Variable Header.
 192
 193   @return Pointer to Variable Data.
 194
 195 **/
 196 UINT8 *
 197 GetVariableDataPtr (
 198   IN  VARIABLE_HEADER   *Variable
 199   );
 200
 201 /**
 202
 203   This code gets the size of variable data.
 204
 205   @param Variable        Pointer to the Variable Header.
 206
 207   @return Size of variable in bytes.
 208
 209 **/
 210 UINTN
 211 DataSizeOfVariable (
 212   IN  VARIABLE_HEADER   *Variable
 213   );
 214
 215 /**
 216   Update the variable region with Variable information. If EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS is set,
 217   index of associated public key is needed.
 218
 219   @param[in] VariableName       Name of variable.
 220   @param[in] VendorGuid         Guid of variable.
 221   @param[in] Data               Variable data.
 222   @param[in] DataSize           Size of data. 0 means delete.
 223   @param[in] Attributes         Attributes of the variable.
 224   @param[in] KeyIndex           Index of associated public key.
 225   @param[in] MonotonicCount     Value of associated monotonic count.
 226   @param[in, out] Variable      The variable information that is used to keep track of variable usage.
 227
 228   @param[in] TimeStamp          Value of associated TimeStamp.
 229
 230   @retval EFI_SUCCESS           The update operation is success.
 231   @retval EFI_OUT_OF_RESOURCES  Variable region is full, cannot write other data into this region.
 232
 233 **/
 234 EFI_STATUS
 235 UpdateVariable (
 236   IN      CHAR16          *VariableName,
 237   IN      EFI_GUID        *VendorGuid,
 238   IN      VOID            *Data,
 239   IN      UINTN           DataSize,
 240   IN      UINT32          Attributes OPTIONAL,
 241   IN      UINT32          KeyIndex  OPTIONAL,
 242   IN      UINT64          MonotonicCount  OPTIONAL,
 243   IN OUT  VARIABLE_POINTER_TRACK *Variable,
 244   IN      EFI_TIME        *TimeStamp  OPTIONAL
 245   );
 246
 247
 248 /**
 249   Return TRUE if ExitBootServices () has been called.
 250
 251   @retval TRUE If ExitBootServices () has been called.
 252 **/
 253 BOOLEAN
 254 AtRuntime (
 255   VOID
 256   );
 257
 258 /**
 259   Initializes a basic mutual exclusion lock.
 260
 261   This function initializes a basic mutual exclusion lock to the released state
 262   and returns the lock.  Each lock provides mutual exclusion access at its task
 263   priority level.  Since there is no preemption or multiprocessor support in EFI,
 264   acquiring the lock only consists of raising to the locks TPL.
 265   If Lock is NULL, then ASSERT().
 266   If Priority is not a valid TPL value, then ASSERT().
 267
 268   @param  Lock       A pointer to the lock data structure to initialize.
 269   @param  Priority   EFI TPL is associated with the lock.
 270
 271   @return The lock.
 272
 273 **/
 274 EFI_LOCK *
 275 InitializeLock (
 276   IN OUT EFI_LOCK  *Lock,
 277   IN EFI_TPL        Priority
 278   );
 279
 280
 281 /**
 282   Acquires lock only at boot time. Simply returns at runtime.
 283
 284   This is a temperary function that will be removed when
 285   EfiAcquireLock() in UefiLib can handle the call in UEFI
 286   Runtimer driver in RT phase.
 287   It calls EfiAcquireLock() at boot time, and simply returns
 288   at runtime.
 289
 290   @param  Lock         A pointer to the lock to acquire.
 291
 292 **/
 293 VOID
 294 AcquireLockOnlyAtBootTime (
 295   IN EFI_LOCK  *Lock
 296   );
 297
 298
 299 /**
 300   Releases lock only at boot time. Simply returns at runtime.
 301
 302   This is a temperary function which will be removed when
 303   EfiReleaseLock() in UefiLib can handle the call in UEFI
 304   Runtimer driver in RT phase.
 305   It calls EfiReleaseLock() at boot time and simply returns
 306   at runtime.
 307
 308   @param  Lock         A pointer to the lock to release.
 309
 310 **/
 311 VOID
 312 ReleaseLockOnlyAtBootTime (
 313   IN EFI_LOCK  *Lock
 314   );
 315
 316 /**
 317   Retrive the FVB protocol interface by HANDLE.
 318
 319   @param[in]  FvBlockHandle     The handle of FVB protocol that provides services for
 320                                 reading, writing, and erasing the target block.
 321   @param[out] FvBlock           The interface of FVB protocol
 322
 323   @retval EFI_SUCCESS           The interface information for the specified protocol was returned.
 324   @retval EFI_UNSUPPORTED       The device does not support the FVB protocol.
 325   @retval EFI_INVALID_PARAMETER FvBlockHandle is not a valid EFI_HANDLE or FvBlock is NULL.
 326
 327 **/
 328 EFI_STATUS
 329 GetFvbByHandle (
 330   IN  EFI_HANDLE                          FvBlockHandle,
 331   OUT EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  **FvBlock
 332   );
 333
 334
 335 /**
 336   Retrive the Swap Address Range protocol interface.
 337
 338   @param[out] SarProtocol       The interface of SAR protocol
 339
 340   @retval EFI_SUCCESS           The SAR protocol instance was found and returned in SarProtocol.
 341   @retval EFI_NOT_FOUND         The SAR protocol instance was not found.
 342   @retval EFI_INVALID_PARAMETER SarProtocol is NULL.
 343
 344 **/
 345 EFI_STATUS
 346 GetSarProtocol (
 347   OUT VOID                                **SarProtocol
 348   );
 349
 350 /**
 351   Function returns an array of handles that support the FVB protocol
 352   in a buffer allocated from pool.
 353
 354   @param[out]  NumberHandles    The number of handles returned in Buffer.
 355   @param[out]  Buffer           A pointer to the buffer to return the requested
 356                                 array of  handles that support FVB protocol.
 357
 358   @retval EFI_SUCCESS           The array of handles was returned in Buffer, and the number of
 359                                 handles in Buffer was returned in NumberHandles.
 360   @retval EFI_NOT_FOUND         No FVB handle was found.
 361   @retval EFI_OUT_OF_RESOURCES  There is not enough pool memory to store the matching results.
 362   @retval EFI_INVALID_PARAMETER NumberHandles is NULL or Buffer is NULL.
 363
 364 **/
 365 EFI_STATUS
 366 GetFvbCountAndBuffer (
 367   OUT UINTN                               *NumberHandles,
 368   OUT EFI_HANDLE                          **Buffer
 369   );
 370
 371 /**
 372   Initializes variable store area for non-volatile and volatile variable.
 373
 374   @retval EFI_SUCCESS           Function successfully executed.
 375   @retval EFI_OUT_OF_RESOURCES  Fail to allocate enough memory resource.
 376
 377 **/
 378 EFI_STATUS
 379 VariableCommonInitialize (
 380   VOID
 381   );
 382
 383 /**
 384
 385   Variable store garbage collection and reclaim operation.
 386
 387   If ReclaimPubKeyStore is FALSE, reclaim variable space by deleting the obsoleted varaibles.
 388   If ReclaimPubKeyStore is TRUE, reclaim invalid key in public key database and update the PubKeyIndex
 389   for all the count-based authenticate variable in NV storage.
 390
 391   @param[in]      VariableBase            Base address of variable store.
 392   @param[out]     LastVariableOffset      Offset of last variable.
 393   @param[in]      IsVolatile              The variable store is volatile or not;
 394                                           if it is non-volatile, need FTW.
 395   @param[in, out] UpdatingPtrTrack        Pointer to updating variable pointer track structure.
 396   @param[in]      ReclaimPubKeyStore      Reclaim for public key database or not.
 397   @param[in]      ReclaimAnyway           If TRUE, do reclaim anyway.
 398
 399   @return EFI_SUCCESS                  Reclaim operation has finished successfully.
 400   @return EFI_OUT_OF_RESOURCES         No enough memory resources.
 401   @return EFI_DEVICE_ERROR             The public key database doesn't exist.
 402   @return Others                       Unexpect error happened during reclaim operation.
 403
 404 **/
 405 EFI_STATUS
 406 Reclaim (
 407   IN     EFI_PHYSICAL_ADDRESS         VariableBase,
 408   OUT    UINTN                        *LastVariableOffset,
 409   IN     BOOLEAN                      IsVolatile,
 410   IN OUT VARIABLE_POINTER_TRACK       *UpdatingPtrTrack,
 411   IN     BOOLEAN                      ReclaimPubKeyStore,
 412   IN     BOOLEAN                      ReclaimAnyway
 413   );
 414
 415 /**
 416   This function reclaims variable storage if free size is below the threshold.
 417
 418 **/
 419 VOID
 420 ReclaimForOS(
 421   VOID
 422   );
 423
 424
 425 /**
 426   Initializes variable write service after FVB was ready.
 427
 428   @retval EFI_SUCCESS          Function successfully executed.
 429   @retval Others               Fail to initialize the variable service.
 430
 431 **/
 432 EFI_STATUS
 433 VariableWriteServiceInitialize (
 434   VOID
 435   );
 436
 437 /**
 438   Retrive the SMM Fault Tolerent Write protocol interface.
 439
 440   @param[out] FtwProtocol       The interface of SMM Ftw protocol
 441
 442   @retval EFI_SUCCESS           The SMM SAR protocol instance was found and returned in SarProtocol.
 443   @retval EFI_NOT_FOUND         The SMM SAR protocol instance was not found.
 444   @retval EFI_INVALID_PARAMETER SarProtocol is NULL.
 445
 446 **/
 447 EFI_STATUS
 448 GetFtwProtocol (
 449   OUT VOID                                **FtwProtocol
 450   );
 451
 452 /**
 453   Get the proper fvb handle and/or fvb protocol by the given Flash address.
 454
 455   @param[in] Address        The Flash address.
 456   @param[out] FvbHandle     In output, if it is not NULL, it points to the proper FVB handle.
 457   @param[out] FvbProtocol   In output, if it is not NULL, it points to the proper FVB protocol.
 458
 459 **/
 460 EFI_STATUS
 461 GetFvbInfoByAddress (
 462   IN  EFI_PHYSICAL_ADDRESS                Address,
 463   OUT EFI_HANDLE                          *FvbHandle OPTIONAL,
 464   OUT EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  **FvbProtocol OPTIONAL
 465   );
 466
 467 /**
 468
 469   This code finds variable in storage blocks (Volatile or Non-Volatile).
 470
 471   Caution: This function may receive untrusted input.
 472   This function may be invoked in SMM mode, and datasize and data are external input.
 473   This function will do basic validation, before parse the data.
 474
 475   @param VariableName               Name of Variable to be found.
 476   @param VendorGuid                 Variable vendor GUID.
 477   @param Attributes                 Attribute value of the variable found.
 478   @param DataSize                   Size of Data found. If size is less than the
 479                                     data, this value contains the required size.
 480   @param Data                       Data pointer.
 481
 482   @return EFI_INVALID_PARAMETER     Invalid parameter.
 483   @return EFI_SUCCESS               Find the specified variable.
 484   @return EFI_NOT_FOUND             Not found.
 485   @return EFI_BUFFER_TO_SMALL       DataSize is too small for the result.
 486
 487 **/
 488 EFI_STATUS
 489 EFIAPI
 490 VariableServiceGetVariable (
 491   IN      CHAR16            *VariableName,
 492   IN      EFI_GUID          *VendorGuid,
 493   OUT     UINT32            *Attributes OPTIONAL,
 494   IN OUT  UINTN             *DataSize,
 495   OUT     VOID              *Data
 496   );
 497
 498 /**
 499
 500   This code Finds the Next available variable.
 501
 502   Caution: This function may receive untrusted input.
 503   This function may be invoked in SMM mode. This function will do basic validation, before parse the data.
 504
 505   @param VariableNameSize           Size of the variable name.
 506   @param VariableName               Pointer to variable name.
 507   @param VendorGuid                 Variable Vendor Guid.
 508
 509   @return EFI_INVALID_PARAMETER     Invalid parameter.
 510   @return EFI_SUCCESS               Find the specified variable.
 511   @return EFI_NOT_FOUND             Not found.
 512   @return EFI_BUFFER_TO_SMALL       DataSize is too small for the result.
 513
 514 **/
 515 EFI_STATUS
 516 EFIAPI
 517 VariableServiceGetNextVariableName (
 518   IN OUT  UINTN             *VariableNameSize,
 519   IN OUT  CHAR16            *VariableName,
 520   IN OUT  EFI_GUID          *VendorGuid
 521   );
 522
 523 /**
 524
 525   This code sets variable in storage blocks (Volatile or Non-Volatile).
 526
 527   Caution: This function may receive untrusted input.
 528   This function may be invoked in SMM mode, and datasize and data are external input.
 529   This function will do basic validation, before parse the data.
 530   This function will parse the authentication carefully to avoid security issues, like
 531   buffer overflow, integer overflow.
 532   This function will check attribute carefully to avoid authentication bypass.
 533
 534   @param VariableName                     Name of Variable to be found.
 535   @param VendorGuid                       Variable vendor GUID.
 536   @param Attributes                       Attribute value of the variable found
 537   @param DataSize                         Size of Data found. If size is less than the
 538                                           data, this value contains the required size.
 539   @param Data                             Data pointer.
 540
 541   @return EFI_INVALID_PARAMETER           Invalid parameter.
 542   @return EFI_SUCCESS                     Set successfully.
 543   @return EFI_OUT_OF_RESOURCES            Resource not enough to set variable.
 544   @return EFI_NOT_FOUND                   Not found.
 545   @return EFI_WRITE_PROTECTED             Variable is read-only.
 546
 547 **/
 548 EFI_STATUS
 549 EFIAPI
 550 VariableServiceSetVariable (
 551   IN CHAR16                  *VariableName,
 552   IN EFI_GUID                *VendorGuid,
 553   IN UINT32                  Attributes,
 554   IN UINTN                   DataSize,
 555   IN VOID                    *Data
 556   );
 557
 558 /**
 559
 560   This code returns information about the EFI variables.
 561
 562   Caution: This function may receive untrusted input.
 563   This function may be invoked in SMM mode. This function will do basic validation, before parse the data.
 564
 565   @param Attributes                     Attributes bitmask to specify the type of variables
 566                                         on which to return information.
 567   @param MaximumVariableStorageSize     Pointer to the maximum size of the storage space available
 568                                         for the EFI variables associated with the attributes specified.
 569   @param RemainingVariableStorageSize   Pointer to the remaining size of the storage space available
 570                                         for EFI variables associated with the attributes specified.
 571   @param MaximumVariableSize            Pointer to the maximum size of an individual EFI variables
 572                                         associated with the attributes specified.
 573
 574   @return EFI_INVALID_PARAMETER         An invalid combination of attribute bits was supplied.
 575   @return EFI_SUCCESS                   Query successfully.
 576   @return EFI_UNSUPPORTED               The attribute is not supported on this platform.
 577
 578 **/
 579 EFI_STATUS
 580 EFIAPI
 581 VariableServiceQueryVariableInfo (
 582   IN  UINT32                 Attributes,
 583   OUT UINT64                 *MaximumVariableStorageSize,
 584   OUT UINT64                 *RemainingVariableStorageSize,
 585   OUT UINT64                 *MaximumVariableSize
 586   );
 587
 588 /**
 589   Mark a variable that will become read-only after leaving the DXE phase of execution.
 590
 591   @param[in] This          The VARIABLE_LOCK_PROTOCOL instance.
 592   @param[in] VariableName  A pointer to the variable name that will be made read-only subsequently.
 593   @param[in] VendorGuid    A pointer to the vendor GUID that will be made read-only subsequently.
 594
 595   @retval EFI_SUCCESS           The variable specified by the VariableName and the VendorGuid was marked
 596                                 as pending to be read-only.
 597   @retval EFI_INVALID_PARAMETER VariableName or VendorGuid is NULL.
 598                                 Or VariableName is an empty string.
 599   @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or EFI_EVENT_GROUP_READY_TO_BOOT has
 600                                 already been signaled.
 601   @retval EFI_OUT_OF_RESOURCES  There is not enough resource to hold the lock request.
 602 **/
 603 EFI_STATUS
 604 EFIAPI
 605 VariableLockRequestToLock (
 606   IN CONST EDKII_VARIABLE_LOCK_PROTOCOL *This,
 607   IN       CHAR16                       *VariableName,
 608   IN       EFI_GUID                     *VendorGuid
 609   );
 610
 611 extern VARIABLE_MODULE_GLOBAL  *mVariableModuleGlobal;
 612
 613 #endif