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/** @file
Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <PiPei.h>
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Guid/VariableFormat.h>
#include <Guid/SystemNvDataGuid.h>
#include "PeilessStartupInternal.h"
/**
Check padding data all bit should be 1.
@param[in] Buffer - A pointer to buffer header
@param[in] BufferSize - Buffer size
@retval TRUE - The padding data is valid.
@retval TRUE - The padding data is invalid.
**/
BOOLEAN
CheckPaddingData (
IN UINT8 *Buffer,
IN UINT32 BufferSize
)
{
UINT32 index;
for (index = 0; index < BufferSize; index++) {
if (Buffer[index] != 0xFF) {
return FALSE;
}
}
return TRUE;
}
/**
Check the integrity of CFV data.
@param[in] TdxCfvBase - A pointer to CFV header
@param[in] TdxCfvSize - CFV data size
@retval TRUE - The CFV data is valid.
@retval FALSE - The CFV data is invalid.
**/
BOOLEAN
EFIAPI
TdxValidateCfv (
IN UINT8 *TdxCfvBase,
IN UINT32 TdxCfvSize
)
{
UINT16 Checksum;
UINTN VariableBase;
UINT32 VariableOffset;
UINT32 VariableOffsetBeforeAlign;
EFI_FIRMWARE_VOLUME_HEADER *CfvFvHeader;
VARIABLE_STORE_HEADER *CfvVariableStoreHeader;
AUTHENTICATED_VARIABLE_HEADER *VariableHeader;
static EFI_GUID FvHdrGUID = EFI_SYSTEM_NV_DATA_FV_GUID;
static EFI_GUID VarStoreHdrGUID = EFI_AUTHENTICATED_VARIABLE_GUID;
VariableOffset = 0;
if (TdxCfvBase == NULL) {
DEBUG ((DEBUG_ERROR, "TDX CFV: CFV pointer is NULL\n"));
return FALSE;
}
//
// Verify the header zerovetor, filesystemguid,
// revision, signature, attributes, fvlength, checksum
// HeaderLength cannot be an odd number
//
CfvFvHeader = (EFI_FIRMWARE_VOLUME_HEADER *)TdxCfvBase;
if ((!IsZeroBuffer (CfvFvHeader->ZeroVector, 16)) ||
(!CompareGuid (&FvHdrGUID, &CfvFvHeader->FileSystemGuid)) ||
(CfvFvHeader->Signature != EFI_FVH_SIGNATURE) ||
(CfvFvHeader->Attributes != 0x4feff) ||
(CfvFvHeader->Revision != EFI_FVH_REVISION) ||
(CfvFvHeader->FvLength != TdxCfvSize)
)
{
DEBUG ((DEBUG_ERROR, "TDX CFV: Basic FV headers were invalid\n"));
return FALSE;
}
//
// Verify the header checksum
//
Checksum = CalculateSum16 ((VOID *)CfvFvHeader, CfvFvHeader->HeaderLength);
if (Checksum != 0) {
DEBUG ((DEBUG_ERROR, "TDX CFV: FV checksum was invalid\n"));
return FALSE;
}
//
// Verify the header signature, size, format, state
//
CfvVariableStoreHeader = (VARIABLE_STORE_HEADER *)(TdxCfvBase + CfvFvHeader->HeaderLength);
if ((!CompareGuid (&VarStoreHdrGUID, &CfvVariableStoreHeader->Signature)) ||
(CfvVariableStoreHeader->Format != VARIABLE_STORE_FORMATTED) ||
(CfvVariableStoreHeader->State != VARIABLE_STORE_HEALTHY) ||
(CfvVariableStoreHeader->Size > (CfvFvHeader->FvLength - CfvFvHeader->HeaderLength)) ||
(CfvVariableStoreHeader->Size < sizeof (VARIABLE_STORE_HEADER))
)
{
DEBUG ((DEBUG_ERROR, "TDX CFV: Variable Store header was invalid\n"));
return FALSE;
}
//
// Verify the header startId, state
// Verify data to the end
//
VariableBase = (UINTN)TdxCfvBase + CfvFvHeader->HeaderLength + sizeof (VARIABLE_STORE_HEADER);
while (VariableOffset < (CfvVariableStoreHeader->Size - sizeof (VARIABLE_STORE_HEADER))) {
VariableHeader = (AUTHENTICATED_VARIABLE_HEADER *)(VariableBase + VariableOffset);
if (VariableHeader->StartId != VARIABLE_DATA) {
if (!CheckPaddingData ((UINT8 *)VariableHeader, CfvVariableStoreHeader->Size - sizeof (VARIABLE_STORE_HEADER) - VariableOffset)) {
DEBUG ((DEBUG_ERROR, "TDX CFV: Variable header was invalid\n"));
return FALSE;
}
VariableOffset = CfvVariableStoreHeader->Size - sizeof (VARIABLE_STORE_HEADER);
} else {
if (!((VariableHeader->State == VAR_IN_DELETED_TRANSITION) ||
(VariableHeader->State == VAR_DELETED) ||
(VariableHeader->State == VAR_HEADER_VALID_ONLY) ||
(VariableHeader->State == VAR_ADDED)))
{
DEBUG ((DEBUG_ERROR, "TDX CFV: Variable header was invalid\n"));
return FALSE;
}
VariableOffset += sizeof (AUTHENTICATED_VARIABLE_HEADER) + VariableHeader->NameSize + VariableHeader->DataSize;
// Verify VariableOffset should be less than or equal CfvVariableStoreHeader->Size - sizeof(VARIABLE_STORE_HEADER)
if (VariableOffset > (CfvVariableStoreHeader->Size - sizeof (VARIABLE_STORE_HEADER))) {
DEBUG ((DEBUG_ERROR, "TDX CFV: Variable header was invalid\n"));
return FALSE;
}
VariableOffsetBeforeAlign = VariableOffset;
// 4 byte align
VariableOffset = (VariableOffset + 3) & (UINTN)(~3);
if (!CheckPaddingData ((UINT8 *)(VariableBase + VariableOffsetBeforeAlign), VariableOffset - VariableOffsetBeforeAlign)) {
DEBUG ((DEBUG_ERROR, "TDX CFV: Variable header was invalid\n"));
return FALSE;
}
}
}
return TRUE;
}
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