mirror of
https://github.com/cea-sec/miasm
synced 2026-06-21 13:48:18 +00:00
Fabrice Desclaux
73 lines
1.9 KiB
Python
73 lines
1.9 KiB
Python
from __future__ import print_function
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from miasm.analysis.binary import Container
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from miasm.analysis.machine import Machine
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from miasm.core.asmblock import AsmConstraint
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from miasm.core.locationdb import LocationDB
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def cb_x86_callpop(mdis, cur_bloc, offset_to_dis):
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"""
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1000: call 1005
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1005: pop
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Will give:
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1000: push 1005
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1005: pop
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"""
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# Pattern matching
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if len(cur_bloc.lines) < 1:
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return
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## We want to match a CALL, always the last line of a basic block
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last_instr = cur_bloc.lines[-1]
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if last_instr.name != 'CALL':
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return
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## The destination must be a location
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dst = last_instr.args[0]
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if not dst.is_loc():
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return
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loc_key = dst.loc_key
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offset = mdis.loc_db.get_location_offset(loc_key)
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## The destination must be the next instruction
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if offset != last_instr.offset + last_instr.l:
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return
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# Update instruction instance
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last_instr.name = 'PUSH'
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# Update next blocks to process in the disassembly engine
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cur_bloc.bto.clear()
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cur_bloc.add_cst(loc_key, AsmConstraint.c_next)
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# Prepare a tiny shellcode
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shellcode = (
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b"\xe8\x00\x00\x00\x00" # CALL $
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b"X" # POP EAX
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b"\xc3" # RET
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)
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# Instantiate a x86 32 bit architecture
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machine = Machine("x86_32")
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loc_db = LocationDB()
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cont = Container.from_string(shellcode, loc_db)
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mdis = machine.dis_engine(cont.bin_stream, loc_db=loc_db)
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print("Without callback:\n")
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asmcfg = mdis.dis_multiblock(0)
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print("\n".join(str(block) for block in asmcfg.blocks))
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# Enable callback
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mdis.dis_block_callback = cb_x86_callpop
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print("=" * 40)
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print("With callback:\n")
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asmcfg_after = mdis.dis_multiblock(0)
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print("\n".join(str(block) for block in asmcfg_after.blocks))
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# Ensure the callback has been called
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assert asmcfg.loc_key_to_block(asmcfg.heads()[0]).lines[0].name == "CALL"
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assert asmcfg_after.loc_key_to_block(asmcfg_after.heads()[0]).lines[0].name == "PUSH"
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