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#! /usr/bin/env python
from argparse import ArgumentParser
from pdb import pm
from elfesteem import pe_init
from miasm2.core.cpu import parse_ast
from miasm2.arch.x86.arch import mn_x86, base_expr
from miasm2.core import parse_asm
from miasm2.expression.expression import *
from miasm2.core import asmbloc
parser = ArgumentParser("x86 32bits assembler")
parser.add_argument("source", help="Source to assemble")
args = parser.parse_args()
pe = pe_init.PE()
s_text = pe.SHList.add_section(name="text", addr=0x1000, rawsize=0x1000)
s_iat = pe.SHList.add_section(name="iat", rawsize=0x100)
new_dll = [({"name": "USER32.dll",
"firstthunk": s_iat.addr}, ["MessageBoxA"])]
pe.DirImport.add_dlldesc(new_dll)
s_myimp = pe.SHList.add_section(name="myimp", rawsize=len(pe.DirImport))
pe.DirImport.set_rva(s_myimp.addr)
reg_and_id = dict(mn_x86.regs.all_regs_ids_byname)
def my_ast_int2expr(a):
return ExprInt32(a)
def my_ast_id2expr(t):
return reg_and_id.get(t, ExprId(t, size=32))
my_var_parser = parse_ast(my_ast_id2expr, my_ast_int2expr)
base_expr.setParseAction(my_var_parser)
with open(args.source) as fstream:
source = fstream.read()
blocs, symbol_pool = parse_asm.parse_txt(mn_x86, 32, source)
# fix shellcode addr
symbol_pool.set_offset(symbol_pool.getby_name("main"), pe.rva2virt(s_text.addr))
symbol_pool.set_offset(symbol_pool.getby_name_create("MessageBoxA"),
pe.DirImport.get_funcvirt('MessageBoxA'))
pe.Opthdr.AddressOfEntryPoint = s_text.addr
for bloc in blocs[0]:
print bloc
resolved_b, patches = asmbloc.asm_resolve_final(
mn_x86, blocs[0], symbol_pool)
print patches
for offset, raw in patches.items():
pe.virt[offset] = raw
output = args.source.replace(".S", ".bin")
open(output, 'wb').write(str(pe))
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