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from enum import Enum, Flag
import struct
class ELFPType(Enum):
NULL = 0
LOAD = 1
DYNAMIC = 2
INTERP = 3
NOTE = 4
SHLIB = 5
PHDR = 6
TLS = 7
class ELFPFlag(Flag):
NONE = 0
EXEC = 1
WRITE = 2
READ = 4
class ELFEndian(Enum):
LITTLE = 1
BIG = 2
class ELF64Phdr:
def __init__(self):
self.type = ELFPType.NULL
self.flags = 0
self.offset = 0
self.vaddr = 0
self.paddr = 0
self.filesz = 0
self.memsz = 0
self.align = 0
return
def parse(self, buf, endian):
endian_marker = '>' if endian == ELFEndian.BIG else '<'
entry = struct.unpack('{}IIQQQQQQ'.format(endian_marker), buf)
self.type = ELFPType(entry[0])
self.flags = ELFPFlag.NONE
self.offset = entry[2]
self.vaddr = entry[3]
self.paddr = entry[4]
self.filesz = entry[5]
self.memsz = entry[6]
self.align = entry[7]
if entry[1] & ELFPFlag.READ.value: self.flags |= ELFPFlag.READ
if entry[1] & ELFPFlag.WRITE.value: self.flags |= ELFPFlag.WRITE
if entry[1] & ELFPFlag.EXEC.value: self.flags |= ELFPFlag.EXEC
class ELF64Image:
def __init__(self):
self.ph_list = []
self.text = None
self.data = None
self.entry = None
def load(self, path):
f = open(path, mode='rb')
ident_bytes = f.read(16)
ident = struct.unpack('BBBBBBBBBBBBBBBB', ident_bytes)
if ident[0] != 0x7F or ident[1] != ord('E') or ident[2] != ord('L') or ident[3] != ord('F'):
f.close()
return -1
endian = ELFEndian(ident[5])
endian_marker = '>' if endian == ELFEndian.BIG else '<'
hdr_bytes = f.read(48)
hdr = struct.unpack('{}HHIQQQIHHHHHH'.format(endian_marker), hdr_bytes)
self.entry = hdr[3]
phoff = hdr[4]
phnum = hdr[9]
phentsize = hdr[8]
for i in range(0, phnum):
f.seek(phoff + (i * phentsize))
phdr_bytes = f.read(phentsize)
phdr = ELF64Phdr()
phdr.parse(phdr_bytes, endian)
if phdr.flags == ELFPFlag.READ | ELFPFlag.EXEC:
self.text = phdr
if phdr.flags == ELFPFlag.READ | ELFPFlag.WRITE:
self.data = phdr
self.ph_list.append(phdr)
f.close()
return 0