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/** @file
FFS file access utilities.
Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "DxeMain.h"
#include "FwVolDriver.h"
/**
Get the FFS file state by checking the highest bit set in the header's state field.
@param ErasePolarity Erase polarity attribute of the firmware volume
@param FfsHeader Points to the FFS file header
@return FFS File state
**/
EFI_FFS_FILE_STATE
GetFileState (
IN UINT8 ErasePolarity,
IN EFI_FFS_FILE_HEADER *FfsHeader
)
{
EFI_FFS_FILE_STATE FileState;
UINT8 HighestBit;
FileState = FfsHeader->State;
if (ErasePolarity != 0) {
FileState = (EFI_FFS_FILE_STATE)~FileState;
}
HighestBit = 0x80;
while (HighestBit != 0 && ((HighestBit & FileState) == 0)) {
HighestBit >>= 1;
}
return (EFI_FFS_FILE_STATE) HighestBit;
}
/**
Check if a block of buffer is erased.
@param ErasePolarity Erase polarity attribute of the firmware volume
@param InBuffer The buffer to be checked
@param BufferSize Size of the buffer in bytes
@retval TRUE The block of buffer is erased
@retval FALSE The block of buffer is not erased
**/
BOOLEAN
IsBufferErased (
IN UINT8 ErasePolarity,
IN VOID *InBuffer,
IN UINTN BufferSize
)
{
UINTN Count;
UINT8 EraseByte;
UINT8 *Buffer;
if(ErasePolarity == 1) {
EraseByte = 0xFF;
} else {
EraseByte = 0;
}
Buffer = InBuffer;
for (Count = 0; Count < BufferSize; Count++) {
if (Buffer[Count] != EraseByte) {
return FALSE;
}
}
return TRUE;
}
/**
Verify checksum of the firmware volume header.
@param FvHeader Points to the firmware volume header to be checked
@retval TRUE Checksum verification passed
@retval FALSE Checksum verification failed
**/
BOOLEAN
VerifyFvHeaderChecksum (
IN EFI_FIRMWARE_VOLUME_HEADER *FvHeader
)
{
UINT16 Checksum;
Checksum = CalculateSum16 ((UINT16 *) FvHeader, FvHeader->HeaderLength);
if (Checksum == 0) {
return TRUE;
} else {
return FALSE;
}
}
/**
Verify checksum of the FFS file header.
@param FfsHeader Points to the FFS file header to be checked
@retval TRUE Checksum verification passed
@retval FALSE Checksum verification failed
**/
BOOLEAN
VerifyHeaderChecksum (
IN EFI_FFS_FILE_HEADER *FfsHeader
)
{
UINT8 HeaderChecksum;
if (IS_FFS_FILE2 (FfsHeader)) {
HeaderChecksum = CalculateSum8 ((UINT8 *) FfsHeader, sizeof (EFI_FFS_FILE_HEADER2));
} else {
HeaderChecksum = CalculateSum8 ((UINT8 *) FfsHeader, sizeof (EFI_FFS_FILE_HEADER));
}
HeaderChecksum = (UINT8) (HeaderChecksum - FfsHeader->State - FfsHeader->IntegrityCheck.Checksum.File);
if (HeaderChecksum == 0) {
return TRUE;
} else {
return FALSE;
}
}
/**
Check if it's a valid FFS file header.
@param ErasePolarity Erase polarity attribute of the firmware volume
@param FfsHeader Points to the FFS file header to be checked
@param FileState FFS file state to be returned
@retval TRUE Valid FFS file header
@retval FALSE Invalid FFS file header
**/
BOOLEAN
IsValidFfsHeader (
IN UINT8 ErasePolarity,
IN EFI_FFS_FILE_HEADER *FfsHeader,
OUT EFI_FFS_FILE_STATE *FileState
)
{
*FileState = GetFileState (ErasePolarity, FfsHeader);
switch (*FileState) {
case EFI_FILE_HEADER_VALID:
case EFI_FILE_DATA_VALID:
case EFI_FILE_MARKED_FOR_UPDATE:
case EFI_FILE_DELETED:
//
// Here we need to verify header checksum
//
return VerifyHeaderChecksum (FfsHeader);
case EFI_FILE_HEADER_CONSTRUCTION:
case EFI_FILE_HEADER_INVALID:
default:
return FALSE;
}
}
/**
Check if it's a valid FFS file.
Here we are sure that it has a valid FFS file header since we must call IsValidFfsHeader() first.
@param ErasePolarity Erase polarity attribute of the firmware volume
@param FfsHeader Points to the FFS file to be checked
@retval TRUE Valid FFS file
@retval FALSE Invalid FFS file
**/
BOOLEAN
IsValidFfsFile (
IN UINT8 ErasePolarity,
IN EFI_FFS_FILE_HEADER *FfsHeader
)
{
EFI_FFS_FILE_STATE FileState;
UINT8 DataCheckSum;
FileState = GetFileState (ErasePolarity, FfsHeader);
switch (FileState) {
case EFI_FILE_DELETED:
case EFI_FILE_DATA_VALID:
case EFI_FILE_MARKED_FOR_UPDATE:
DataCheckSum = FFS_FIXED_CHECKSUM;
if ((FfsHeader->Attributes & FFS_ATTRIB_CHECKSUM) == FFS_ATTRIB_CHECKSUM) {
if (IS_FFS_FILE2 (FfsHeader)) {
DataCheckSum = CalculateCheckSum8 ((CONST UINT8 *) FfsHeader + sizeof (EFI_FFS_FILE_HEADER2), FFS_FILE2_SIZE (FfsHeader) - sizeof(EFI_FFS_FILE_HEADER2));
} else {
DataCheckSum = CalculateCheckSum8 ((CONST UINT8 *) FfsHeader + sizeof (EFI_FFS_FILE_HEADER), FFS_FILE_SIZE (FfsHeader) - sizeof(EFI_FFS_FILE_HEADER));
}
}
if (FfsHeader->IntegrityCheck.Checksum.File == DataCheckSum) {
return TRUE;
}
default:
return FALSE;
}
}
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