def modify_uefi_region(data, command, guid, uefi_file = ''):
RgLengthChange = 0
fv = NextFwVolume(data)
while fv is not None:
FvLengthChange = 0
polarity = bit_set(fv.Attributes, EFI_FVB2_ERASE_POLARITY)
if ((fv.Guid == EFI_FIRMWARE_FILE_SYSTEM2_GUID) or (fv.Guid == EFI_FIRMWARE_FILE_SYSTEM_GUID)):
fwbin = NextFwFile(fv.Image, fv.Size, fv.HeaderSize, polarity)
while fwbin is not None:
next_offset = fwbin.Size + fwbin.Offset
if (fwbin.Guid == guid):
uefi_file_size = (len(uefi_file) + 7) & 0xFFFFFFF8
CurFileOffset = fv.Offset + fwbin.Offset + FvLengthChange
NxtFileOffset = fv.Offset + next_offset + FvLengthChange
if command == CMD_UEFI_FILE_REMOVE:
FvLengthChange -= (next_offset - fwbin.Offset)
logger().log( "Removing UEFI file with GUID={} at offset={:08X}, size change: {:d} bytes".format(fwbin.Guid, CurFileOffset, FvLengthChange) )
data = data[:CurFileOffset] + data[NxtFileOffset:]
elif command == CMD_UEFI_FILE_INSERT_BEFORE:
FvLengthChange += uefi_file_size
logger().log( "Inserting UEFI file before file with GUID={} at offset={:08X}, size change: {:d} bytes".format(fwbin.Guid, CurFileOffset, FvLengthChange) )
data = data[:CurFileOffset] + uefi_file.ljust(uefi_file_size, '\xFF') + data[CurFileOffset:]
elif command == CMD_UEFI_FILE_INSERT_AFTER:
FvLengthChange += uefi_file_size
logger().log( "Inserting UEFI file after file with GUID={} at offset={:08X}, size change: {:d} bytes".format(fwbin.Guid, CurFileOffset, FvLengthChange) )
data = data[:NxtFileOffset] + uefi_file.ljust(uefi_file_size, '\xFF') + data[NxtFileOffset:]
elif command == CMD_UEFI_FILE_REPLACE:
FvLengthChange += uefi_file_size - (next_offset - fwbin.Offset)
logger().log( "Replacing UEFI file with GUID={} at offset={:08X}, new size: {:d}, old size: {:d}, size change: {:d} bytes".format(fwbin.Guid, CurFileOffset, len(uefi_file), fwbin.Size, FvLengthChange) )
data = data[:CurFileOffset] + uefi_file.ljust(uefi_file_size, '\xFF') + data[NxtFileOffset:]
else:
raise Exception('Invalid command')
if next_offset - fwbin.Offset >= 24:
FvEndOffset = fv.Offset + next_offset + FvLengthChange
fwbin = NextFwFile(fv.Image, fv.Size, next_offset, polarity)
if FvLengthChange >= 0:
data = data[:FvEndOffset] + data[FvEndOffset + FvLengthChange:]
else:
data = data[:FvEndOffset] + (abs(FvLengthChange) * '\xFF') + data[FvEndOffset:]
FvLengthChange = 0
#if FvLengthChange != 0:
# logger().log( "Rebuilding Firmware Volume with GUID={} at offset={:08X}".format(FsGuid, FvOffset) )
# FvHeader = data[FvOffset: FvOffset + FvHeaderLength]
# FvHeader = FvHeader[:0x20] + struct.pack('<Q', FvLength) + FvHeader[0x28:]
# NewChecksum = FvChecksum16(FvHeader[:0x32] + '\x00\x00' + FvHeader[0x34:])
# FvHeader = FvHeader[:0x32] + struct.pack('<H', NewChecksum) + FvHeader[0x34:]
# data = data[:FvOffset] + FvHeader + data[FvOffset + FvHeaderLength:]
fv = NextFwVolume(data, fv.Offset + fv.Size)
return data
def NextFwFile(FvImage, FvLength, fof, polarity):
file_header_size = struct.calcsize(EFI_FFS_FILE_HEADER)
fof = align(fof, 8)
cur_offset = fof
res = None
update_or_deleted = False
while cur_offset + file_header_size < min(FvLength, len(FvImage)):
fsize = 0
#if (fof + file_header_size) <= min(FvLength, len(FvImage)):
#Check for a blank header
if polarity:
blank = b"\xff" * file_header_size
else:
blank = b"\x00" * file_header_size
if (blank == FvImage[cur_offset:cur_offset + file_header_size]):
#next_offset = fof + 8
cur_offset += 8
continue
Name0, IntegrityCheck, Type, Attributes, Size, State = struct.unpack(
EFI_FFS_FILE_HEADER,
FvImage[cur_offset:cur_offset + file_header_size])
#Get File Header Size
if Attributes & FFS_ATTRIB_LARGE_FILE:
header_size = struct.calcsize(EFI_FFS_FILE_HEADER2)
else:
header_size = struct.calcsize(EFI_FFS_FILE_HEADER)
#Get File size
if Attributes & FFS_ATTRIB_LARGE_FILE and len(
FvImage) > fof + struct.calcsize(EFI_FFS_FILE_HEADER2):
fsize = struct.unpack(
"Q", FvImage[fof + file_header_size:fof + file_header_size +
struct.calcsize("Q")])[0]
fsize &= 0xFFFFFFFF
if fsize == 0 or fsize > FvLength - cur_offset:
fsize = get_3b_size(Size)
#Validate fsize is a legal value
if fsize == 0 or fsize > FvLength - cur_offset:
logger().log(
"Unable to get correct file size for NextFwFile corrupt header information"
)
break
#Get next_offset
update_or_deleted = (bit_set(State, EFI_FILE_MARKED_FOR_UPDATE,
polarity)) or (bit_set(
State, EFI_FILE_DELETED, polarity))
if not ((bit_set(State, EFI_FILE_DATA_VALID, polarity))
or update_or_deleted):
#else:
cur_offset = align(cur_offset + 1, 8)
continue
Name = UUID(bytes_le=Name0)
#TODO need to fix up checksum?
fheader = struct.pack(EFI_FFS_FILE_HEADER, Name0, 0, Type, Attributes,
Size, 0)
hsum = FvChecksum8(fheader)
if (Attributes & FFS_ATTRIB_CHECKSUM):
fsum = FvChecksum8(FvImage[cur_offset +
file_header_size:cur_offset + fsize])
else:
fsum = FFS_FIXED_CHECKSUM
CalcSum = (hsum | (fsum << 8))
res = EFI_FILE(cur_offset, Name, Type, Attributes, State,
IntegrityCheck, fsize,
FvImage[cur_offset:cur_offset + fsize], header_size,
update_or_deleted, CalcSum)
break
return res
