path: root/MdeModulePkg/Library/VarCheckLib/VarCheckLib.c

/** @file
  Implementation functions and structures for var check services.

Copyright (c) 2015 - 2021, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include <Library/VarCheckLib.h>
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/MemoryAllocationLib.h>

#include <Guid/GlobalVariable.h>
#include <Guid/HardwareErrorVariable.h>

BOOLEAN mVarCheckLibEndOfDxe    = FALSE;

#define VAR_CHECK_TABLE_SIZE    0x8

UINTN                                   mVarCheckLibEndOfDxeCallbackCount = 0;
UINTN                                   mVarCheckLibEndOfDxeCallbackMaxCount = 0;
VAR_CHECK_END_OF_DXE_CALLBACK           *mVarCheckLibEndOfDxeCallback = NULL;

UINTN                                   mVarCheckLibAddressPointerCount = 0;
UINTN                                   mVarCheckLibAddressPointerMaxCount = 0;
VOID                                    ***mVarCheckLibAddressPointer = NULL;

UINTN                                   mNumberOfVarCheckHandler = 0;
UINTN                                   mMaxNumberOfVarCheckHandler = 0;
VAR_CHECK_SET_VARIABLE_CHECK_HANDLER    *mVarCheckHandlerTable = NULL;

typedef struct {
  EFI_GUID                      Guid;
  VAR_CHECK_VARIABLE_PROPERTY   VariableProperty;
  //CHAR16                        *Name;
} VAR_CHECK_VARIABLE_ENTRY;

UINTN                                   mNumberOfVarCheckVariable = 0;
UINTN                                   mMaxNumberOfVarCheckVariable = 0;
VARIABLE_ENTRY_PROPERTY                 **mVarCheckVariableTable = NULL;

//
// Handle variables with wildcard name specially.
//
VARIABLE_ENTRY_PROPERTY mVarCheckVariableWithWildcardName[] = {
  {
    &gEfiGlobalVariableGuid,
    L"Boot####",
    {
      0
    },
  },
  {
    &gEfiGlobalVariableGuid,
    L"Driver####",
    {
      0
    },
  },
  {
    &gEfiGlobalVariableGuid,
    L"SysPrep####",
    {
      0
    },
  },
  {
    &gEfiGlobalVariableGuid,
    L"Key####",
    {
      0
    },
  },
  {
    &gEfiGlobalVariableGuid,
    L"PlatformRecovery####",
    {
      0
    },
  },
  {
    &gEfiHardwareErrorVariableGuid,
    L"HwErrRec####",
    {
      0
    },
  },
};

/**
  Check if a Unicode character is an upper case hexadecimal character.

  This function checks if a Unicode character is an upper case
  hexadecimal character.  The valid upper case hexadecimal character is
  L'0' to L'9', or L'A' to L'F'.


  @param[in] Char       The character to check against.

  @retval TRUE          If the Char is an upper case hexadecmial character.
  @retval FALSE         If the Char is not an upper case hexadecmial character.

**/
BOOLEAN
EFIAPI
VarCheckInternalIsHexaDecimalDigitCharacter (
  IN CHAR16             Char
  )
{
  return (BOOLEAN) ((Char >= L'0' && Char <= L'9') || (Char >= L'A' && Char <= L'F'));
}

/**
  Variable property get with wildcard name.

  @param[in] VariableName       Pointer to variable name.
  @param[in] VendorGuid         Pointer to variable vendor GUID.
  @param[in] WildcardMatch      Try wildcard match or not.

  @return Pointer to variable property.

**/
VAR_CHECK_VARIABLE_PROPERTY *
VariablePropertyGetWithWildcardName (
  IN CHAR16                         *VariableName,
  IN EFI_GUID                       *VendorGuid,
  IN BOOLEAN                        WildcardMatch
  )
{
  UINTN     Index;
  UINTN     NameLength;

  NameLength = StrLen (VariableName) - 4;
  for (Index = 0; Index < sizeof (mVarCheckVariableWithWildcardName)/sizeof (mVarCheckVariableWithWildcardName[0]); Index++) {
    if (CompareGuid (mVarCheckVariableWithWildcardName[Index].Guid, VendorGuid)){
      if (WildcardMatch) {
        if ((StrLen (VariableName) == StrLen (mVarCheckVariableWithWildcardName[Index].Name)) &&
            (StrnCmp (VariableName, mVarCheckVariableWithWildcardName[Index].Name, NameLength) == 0) &&
            VarCheckInternalIsHexaDecimalDigitCharacter (VariableName[NameLength]) &&
            VarCheckInternalIsHexaDecimalDigitCharacter (VariableName[NameLength + 1]) &&
            VarCheckInternalIsHexaDecimalDigitCharacter (VariableName[NameLength + 2]) &&
            VarCheckInternalIsHexaDecimalDigitCharacter (VariableName[NameLength + 3])) {
          return &mVarCheckVariableWithWildcardName[Index].VariableProperty;
        }
      }
      if (StrCmp (mVarCheckVariableWithWildcardName[Index].Name, VariableName) == 0) {
        return  &mVarCheckVariableWithWildcardName[Index].VariableProperty;
      }
    }
  }

  return NULL;
}

/**
  Variable property get function.

  @param[in] Name           Pointer to the variable name.
  @param[in] Guid           Pointer to the vendor GUID.
  @param[in] WildcardMatch  Try wildcard match or not.

  @return Pointer to the property of variable specified by the Name and Guid.

**/
VAR_CHECK_VARIABLE_PROPERTY *
VariablePropertyGetFunction (
  IN CHAR16                 *Name,
  IN EFI_GUID               *Guid,
  IN BOOLEAN                WildcardMatch
  )
{
  UINTN                     Index;
  VAR_CHECK_VARIABLE_ENTRY  *Entry;
  CHAR16                    *VariableName;

  for (Index = 0; Index < mNumberOfVarCheckVariable; Index++) {
    Entry = (VAR_CHECK_VARIABLE_ENTRY *) mVarCheckVariableTable[Index];
    VariableName = (CHAR16 *) ((UINTN) Entry + sizeof (*Entry));
    if (CompareGuid (&Entry->Guid, Guid) && (StrCmp (VariableName, Name) == 0)) {
      return &Entry->VariableProperty;
    }
  }

  return VariablePropertyGetWithWildcardName (Name, Guid, WildcardMatch);
}

/**
  Var check add table entry.

  @param[in, out] Table         Pointer to table buffer.
  @param[in, out] MaxNumber     Pointer to maximum number of entry in the table.
  @param[in, out] CurrentNumber Pointer to current number of entry in the table.
  @param[in]      Entry         Entry will be added to the table.

  @retval EFI_SUCCESS           Reallocate memory successfully.
  @retval EFI_OUT_OF_RESOURCES  No enough memory to allocate.

**/
EFI_STATUS
VarCheckAddTableEntry (
  IN OUT UINTN      **Table,
  IN OUT UINTN      *MaxNumber,
  IN OUT UINTN      *CurrentNumber,
  IN UINTN          Entry
  )
{
  UINTN     *TempTable;

  //
  // Check whether the table is enough to store new entry.
  //
  if (*CurrentNumber == *MaxNumber) {
    //
    // Reallocate memory for the table.
    //
    TempTable = ReallocateRuntimePool (
                  *MaxNumber * sizeof (UINTN),
                  (*MaxNumber + VAR_CHECK_TABLE_SIZE) * sizeof (UINTN),
                  *Table
                  );

    //
    // No enough resource to allocate.
    //
    if (TempTable == NULL) {
      return EFI_OUT_OF_RESOURCES;
    }

    *Table = TempTable;
    //
    // Increase max number.
    //
    *MaxNumber += VAR_CHECK_TABLE_SIZE;
  }

  //
  // Add entry to the table.
  //
  (*Table)[*CurrentNumber] = Entry;
  (*CurrentNumber)++;

  return EFI_SUCCESS;
}

/**
  Register END_OF_DXE callback.
  The callback will be invoked by VarCheckLibInitializeAtEndOfDxe().

  @param[in] Callback           END_OF_DXE callback.

  @retval EFI_SUCCESS           The callback was registered successfully.
  @retval EFI_INVALID_PARAMETER Callback is NULL.
  @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or EFI_EVENT_GROUP_READY_TO_BOOT has
                                already been signaled.
  @retval EFI_OUT_OF_RESOURCES  There is not enough resource for the callback register request.

**/
EFI_STATUS
EFIAPI
VarCheckLibRegisterEndOfDxeCallback (
  IN VAR_CHECK_END_OF_DXE_CALLBACK  Callback
  )
{
  EFI_STATUS    Status;

  if (Callback == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  if (mVarCheckLibEndOfDxe) {
    return EFI_ACCESS_DENIED;
  }

  Status = VarCheckAddTableEntry (
           (UINTN **) &mVarCheckLibEndOfDxeCallback,
           &mVarCheckLibEndOfDxeCallbackMaxCount,
           &mVarCheckLibEndOfDxeCallbackCount,
           (UINTN) Callback
           );

  DEBUG ((EFI_D_INFO, "VarCheckLibRegisterEndOfDxeCallback - 0x%x %r\n", Callback, Status));

  return Status;
}

/**
  Var check initialize at END_OF_DXE.

  This function needs to be called at END_OF_DXE.
  Address pointers may be returned,
  and caller needs to ConvertPointer() for the pointers.

  @param[in, out] AddressPointerCount   Output pointer to address pointer count.

  @return Address pointer buffer, NULL if input AddressPointerCount is NULL.

**/
VOID ***
EFIAPI
VarCheckLibInitializeAtEndOfDxe (
  IN OUT UINTN                  *AddressPointerCount OPTIONAL
  )
{
  VOID                          *TempTable;
  UINTN                         TotalCount;
  UINTN                         Index;

  for (Index = 0; Index < mVarCheckLibEndOfDxeCallbackCount; Index++) {
    //
    // Invoke the callback registered by VarCheckLibRegisterEndOfDxeCallback().
    //
    mVarCheckLibEndOfDxeCallback[Index] ();
  }
  if (mVarCheckLibEndOfDxeCallback != NULL) {
    //
    // Free the callback buffer.
    //
    mVarCheckLibEndOfDxeCallbackCount = 0;
    mVarCheckLibEndOfDxeCallbackMaxCount = 0;
    FreePool ((VOID *) mVarCheckLibEndOfDxeCallback);
    mVarCheckLibEndOfDxeCallback = NULL;
  }

  mVarCheckLibEndOfDxe = TRUE;

  if (AddressPointerCount == NULL) {
    if (mVarCheckLibAddressPointer != NULL) {
      //
      // Free the address pointer buffer.
      //
      mVarCheckLibAddressPointerCount = 0;
      mVarCheckLibAddressPointerMaxCount = 0;
      FreePool ((VOID *) mVarCheckLibAddressPointer);
      mVarCheckLibAddressPointer = NULL;
    }
    return NULL;
  }

  //
  // Get the total count needed.
  // Also cover VarCheckHandler and the entries, and VarCheckVariable and the entries.
  //
  TotalCount = mVarCheckLibAddressPointerCount + (mNumberOfVarCheckHandler + 1) + (mNumberOfVarCheckVariable + 1);
  TempTable = ReallocateRuntimePool (
                mVarCheckLibAddressPointerMaxCount * sizeof (VOID **),
                TotalCount * sizeof (VOID **),
                (VOID *) mVarCheckLibAddressPointer
                );

  if (TempTable != NULL) {
    mVarCheckLibAddressPointer = (VOID ***) TempTable;

    //
    // Cover VarCheckHandler and the entries.
    //
    mVarCheckLibAddressPointer[mVarCheckLibAddressPointerCount++] = (VOID **) &mVarCheckHandlerTable;
    for (Index = 0; Index < mNumberOfVarCheckHandler; Index++) {
      mVarCheckLibAddressPointer[mVarCheckLibAddressPointerCount++] = (VOID **) &mVarCheckHandlerTable[Index];
    }

    //
    // Cover VarCheckVariable and the entries.
    //
    mVarCheckLibAddressPointer[mVarCheckLibAddressPointerCount++] = (VOID **) &mVarCheckVariableTable;
    for (Index = 0; Index < mNumberOfVarCheckVariable; Index++) {
      mVarCheckLibAddressPointer[mVarCheckLibAddressPointerCount++] = (VOID **) &mVarCheckVariableTable[Index];
    }

    ASSERT (mVarCheckLibAddressPointerCount == TotalCount);
    mVarCheckLibAddressPointerMaxCount = mVarCheckLibAddressPointerCount;
  }

  *AddressPointerCount = mVarCheckLibAddressPointerCount;
  return mVarCheckLibAddressPointer;
}

/**
  Register address pointer.
  The AddressPointer may be returned by VarCheckLibInitializeAtEndOfDxe().

  @param[in] AddressPointer     Address pointer.

  @retval EFI_SUCCESS           The address pointer was registered successfully.
  @retval EFI_INVALID_PARAMETER AddressPointer is NULL.
  @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or EFI_EVENT_GROUP_READY_TO_BOOT has
                                already been signaled.
  @retval EFI_OUT_OF_RESOURCES  There is not enough resource for the address pointer register request.

**/
EFI_STATUS
EFIAPI
VarCheckLibRegisterAddressPointer (
  IN VOID                       **AddressPointer
  )
{
  EFI_STATUS    Status;

  if (AddressPointer == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  if (mVarCheckLibEndOfDxe) {
    return EFI_ACCESS_DENIED;
  }

  Status = VarCheckAddTableEntry(
           (UINTN **) &mVarCheckLibAddressPointer,
           &mVarCheckLibAddressPointerMaxCount,
           &mVarCheckLibAddressPointerCount,
           (UINTN) AddressPointer
           );

  DEBUG ((EFI_D_INFO, "VarCheckLibRegisterAddressPointer - 0x%x %r\n", AddressPointer, Status));

  return Status;
}

/**
  Register SetVariable check handler.

  @param[in] Handler            Pointer to check handler.

  @retval EFI_SUCCESS           The SetVariable check handler was registered successfully.
  @retval EFI_INVALID_PARAMETER Handler is NULL.
  @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or EFI_EVENT_GROUP_READY_TO_BOOT has
                                already been signaled.
  @retval EFI_OUT_OF_RESOURCES  There is not enough resource for the SetVariable check handler register request.
  @retval EFI_UNSUPPORTED       This interface is not implemented.
                                For example, it is unsupported in VarCheck protocol if both VarCheck and SmmVarCheck protocols are present.

**/
EFI_STATUS
EFIAPI
VarCheckLibRegisterSetVariableCheckHandler (
  IN VAR_CHECK_SET_VARIABLE_CHECK_HANDLER   Handler
  )
{
  EFI_STATUS    Status;

  if (Handler == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  if (mVarCheckLibEndOfDxe) {
    return EFI_ACCESS_DENIED;
  }

  Status =  VarCheckAddTableEntry(
             (UINTN **) &mVarCheckHandlerTable,
             &mMaxNumberOfVarCheckHandler,
             &mNumberOfVarCheckHandler,
             (UINTN) Handler
             );

  DEBUG ((EFI_D_INFO, "VarCheckLibRegisterSetVariableCheckHandler - 0x%x %r\n", Handler, Status));

  return Status;
}

/**
  Variable property set.

  @param[in] Name               Pointer to the variable name.
  @param[in] Guid               Pointer to the vendor GUID.
  @param[in] VariableProperty   Pointer to the input variable property.

  @retval EFI_SUCCESS           The property of variable specified by the Name and Guid was set successfully.
  @retval EFI_INVALID_PARAMETER Name, Guid or VariableProperty is NULL, or Name is an empty string,
                                or the fields of VariableProperty are not valid.
  @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or EFI_EVENT_GROUP_READY_TO_BOOT has
                                already been signaled.
  @retval EFI_OUT_OF_RESOURCES  There is not enough resource for the variable property set request.

**/
EFI_STATUS
EFIAPI
VarCheckLibVariablePropertySet (
  IN CHAR16                         *Name,
  IN EFI_GUID                       *Guid,
  IN VAR_CHECK_VARIABLE_PROPERTY    *VariableProperty
  )
{
  EFI_STATUS                    Status;
  VAR_CHECK_VARIABLE_ENTRY      *Entry;
  CHAR16                        *VariableName;
  VAR_CHECK_VARIABLE_PROPERTY   *Property;

  if (Name == NULL || Name[0] == 0 || Guid == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  if (VariableProperty == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  if (VariableProperty->Revision != VAR_CHECK_VARIABLE_PROPERTY_REVISION) {
    return EFI_INVALID_PARAMETER;
  }

  if (mVarCheckLibEndOfDxe) {
    return EFI_ACCESS_DENIED;
  }

  Status = EFI_SUCCESS;

  //
  // Get the pointer of property data for set.
  //
  Property = VariablePropertyGetFunction (Name, Guid, FALSE);
  if (Property != NULL) {
    CopyMem (Property, VariableProperty, sizeof (*VariableProperty));
  } else {
    Entry = AllocateRuntimeZeroPool (sizeof (*Entry) + StrSize (Name));
    if (Entry == NULL) {
      return EFI_OUT_OF_RESOURCES;
    }
    VariableName = (CHAR16 *) ((UINTN) Entry + sizeof (*Entry));
    StrCpyS (VariableName, StrSize (Name)/sizeof (CHAR16), Name);
    CopyGuid (&Entry->Guid, Guid);
    CopyMem (&Entry->VariableProperty, VariableProperty, sizeof (*VariableProperty));

    Status = VarCheckAddTableEntry(
               (UINTN **) &mVarCheckVariableTable,
               &mMaxNumberOfVarCheckVariable,
               &mNumberOfVarCheckVariable,
               (UINTN) Entry
               );

    if (EFI_ERROR (Status)) {
      FreePool (Entry);
    }
  }

  return Status;
}

/**
  Variable property get.

  @param[in]  Name              Pointer to the variable name.
  @param[in]  Guid              Pointer to the vendor GUID.
  @param[out] VariableProperty  Pointer to the output variable property.

  @retval EFI_SUCCESS           The property of variable specified by the Name and Guid was got successfully.
  @retval EFI_INVALID_PARAMETER Name, Guid or VariableProperty is NULL, or Name is an empty string.
  @retval EFI_NOT_FOUND         The property of variable specified by the Name and Guid was not found.

**/
EFI_STATUS
EFIAPI
VarCheckLibVariablePropertyGet (
  IN CHAR16                         *Name,
  IN EFI_GUID                       *Guid,
  OUT VAR_CHECK_VARIABLE_PROPERTY   *VariableProperty
  )
{
  VAR_CHECK_VARIABLE_PROPERTY   *Property;

  if (Name == NULL || Name[0] == 0 || Guid == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  if (VariableProperty == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  Property = VariablePropertyGetFunction (Name, Guid, TRUE);
  //
  // Also check the property revision before using the property data.
  // There is no property set to this variable(wildcard name)
  // if the revision is not VAR_CHECK_VARIABLE_PROPERTY_REVISION.
  //
  if ((Property != NULL) && (Property->Revision == VAR_CHECK_VARIABLE_PROPERTY_REVISION)) {
    CopyMem (VariableProperty, Property, sizeof (*VariableProperty));
    return EFI_SUCCESS;
  }

  return EFI_NOT_FOUND;
}

/**
  SetVariable check.

  @param[in] VariableName       Name of Variable to set.
  @param[in] VendorGuid         Variable vendor GUID.
  @param[in] Attributes         Attribute value of the variable.
  @param[in] DataSize           Size of Data to set.
  @param[in] Data               Data pointer.
  @param[in] RequestSource      Request source.

  @retval EFI_SUCCESS           The SetVariable check result was success.
  @retval EFI_INVALID_PARAMETER An invalid combination of attribute bits, name, GUID,
                                DataSize and Data value was supplied.
  @retval EFI_WRITE_PROTECTED   The variable in question is read-only.
  @retval Others                The other return status from check handler.

**/
EFI_STATUS
EFIAPI
VarCheckLibSetVariableCheck (
  IN CHAR16                     *VariableName,
  IN EFI_GUID                   *VendorGuid,
  IN UINT32                     Attributes,
  IN UINTN                      DataSize,
  IN VOID                       *Data,
  IN VAR_CHECK_REQUEST_SOURCE   RequestSource
  )
{
  EFI_STATUS                    Status;
  UINTN                         Index;
  VAR_CHECK_VARIABLE_PROPERTY   *Property;

  if (!mVarCheckLibEndOfDxe) {
    //
    // Only do check after End Of Dxe.
    //
    return EFI_SUCCESS;
  }

  Property = VariablePropertyGetFunction (VariableName, VendorGuid, TRUE);
  //
  // Also check the property revision before using the property data.
  // There is no property set to this variable(wildcard name)
  // if the revision is not VAR_CHECK_VARIABLE_PROPERTY_REVISION.
  //
  if ((Property != NULL) && (Property->Revision == VAR_CHECK_VARIABLE_PROPERTY_REVISION)) {
    if ((RequestSource != VarCheckFromTrusted) && ((Property->Property & VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY) != 0)) {
      DEBUG ((EFI_D_INFO, "Variable Check ReadOnly variable fail %r - %g:%s\n", EFI_WRITE_PROTECTED, VendorGuid, VariableName));
      return EFI_WRITE_PROTECTED;
    }
    if (!((((Attributes & EFI_VARIABLE_APPEND_WRITE) == 0) && (DataSize == 0)) || (Attributes == 0))) {
      //
      // Not to delete variable.
      //
      if ((Property->Attributes != 0) && ((Attributes & (~EFI_VARIABLE_APPEND_WRITE)) != Property->Attributes)) {
        DEBUG ((EFI_D_INFO, "Variable Check Attributes(0x%08x to 0x%08x) fail %r - %g:%s\n", Property->Attributes, Attributes, EFI_INVALID_PARAMETER, VendorGuid, VariableName));
        return EFI_INVALID_PARAMETER;
      }
      if (DataSize != 0) {
        if ((DataSize < Property->MinSize) || (DataSize > Property->MaxSize)) {
          DEBUG ((EFI_D_INFO, "Variable Check DataSize fail(0x%x not in 0x%x - 0x%x) %r - %g:%s\n", DataSize, Property->MinSize, Property->MaxSize, EFI_INVALID_PARAMETER, VendorGuid, VariableName));
          return EFI_INVALID_PARAMETER;
        }
      }
    }
  }

  for (Index = 0; Index < mNumberOfVarCheckHandler; Index++) {
    Status = mVarCheckHandlerTable[Index] (
               VariableName,
               VendorGuid,
               Attributes,
               DataSize,
               Data
               );
    if (Status == EFI_WRITE_PROTECTED && RequestSource == VarCheckFromTrusted) {
      //
      // If RequestSource is trusted, then allow variable to be set even if it
      // is write protected.
      //
      continue;
    }
    if (EFI_ERROR (Status)) {
      DEBUG ((EFI_D_INFO, "Variable Check handler fail %r - %g:%s\n", Status, VendorGuid, VariableName));
      return Status;
    }
  }
  return EFI_SUCCESS;
}