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#!/usr/bin/env python
#-*- coding:utf-8 -*-
from sys import stdout
from string import printable
from miasm2.os_dep.common import heap
class c_linobjs(object):
base_addr = 0x20000000
align_addr = 0x1000
def __init__(self):
self.alloc_ad = self.base_addr
self.alloc_align = self.align_addr
self.heap = heap()
linobjs = c_linobjs()
def xxx_isprint(jitter):
'''
#include <ctype.h>
int isprint(int c);
checks for any printable character including space.
'''
ret_addr, args = jitter.func_args_stdcall(['c'])
ret = 1 if chr(args.c & 0xFF) in printable else 0
return jitter.func_ret_stdcall(ret_addr, ret)
def xxx_memcpy(jitter):
'''
#include <string.h>
void *memcpy(void *dest, const void *src, size_t n);
copies n bytes from memory area src to memory area dest.
'''
ret_addr, args = jitter.func_args_stdcall(['dest', 'src', 'n'])
jitter.vm.set_mem(args.dest, jitter.vm.get_mem(args.src, args.n))
return jitter.func_ret_stdcall(ret_addr, args.dest)
def xxx_memset(jitter):
'''
#include <string.h>
void *memset(void *s, int c, size_t n);
fills the first n bytes of the memory area pointed to by s with the constant
byte c.'''
ret_addr, args = jitter.func_args_stdcall(['dest', 'c', 'n'])
jitter.vm.set_mem(args.dest, chr(args.c & 0xFF) * args.n)
return jitter.func_ret_stdcall(ret_addr, args.dest)
def xxx_puts(jitter):
'''
#include <stdio.h>
int puts(const char *s);
writes the string s and a trailing newline to stdout.
'''
ret_addr, args = jitter.func_args_stdcall(['s'])
index = args.s
char = jitter.vm.get_mem(index, 1)
while char != '\x00':
stdout.write(char)
index += 1
char = jitter.vm.get_mem(index, 1)
stdout.write('\n')
return jitter.func_ret_stdcall(ret_addr, 1)
def get_fmt_args(jitter, fmt, cur_arg):
output = ""
while True:
char = jitter.vm.get_mem(fmt, 1)
fmt += 1
if char == '\x00':
break
if char == '%':
token = '%'
while True:
char = jitter.vm.get_mem(fmt, 1)
fmt += 1
token += char
if char.lower() in '%cdfsux':
break
if token.endswith('s'):
arg = jitter.get_str_ansi(jitter.get_arg_n_stdcall(cur_arg))
else:
arg = jitter.get_arg_n_stdcall(cur_arg)
char = token % arg
cur_arg += 1
output += char
return output
def xxx_snprintf(jitter):
ret_addr, args = jitter.func_args_stdcall(['string', 'size', 'fmt'])
cur_arg, fmt = 3, args.fmt
size = args.size if args.size else 1
output = get_fmt_args(jitter, fmt, cur_arg)
output = output[:size - 1]
ret = len(output)
jitter.vm.set_mem(args.string, output + '\x00')
return jitter.func_ret_stdcall(ret_addr, ret)
def xxx_sprintf(jitter):
ret_addr, args = jitter.func_args_stdcall(['string', 'fmt'])
cur_arg, fmt = 2, args.fmt
output = get_fmt_args(jitter, fmt, cur_arg)
ret = len(output)
jitter.vm.set_mem(args.string, output + '\x00')
return jitter.func_ret_stdcall(ret_addr, ret)
def xxx_printf(jitter):
ret_addr, args = jitter.func_args_stdcall(['fmt'])
cur_arg, fmt = 1, args.fmt
output = get_fmt_args(jitter, fmt, cur_arg)
ret = len(output)
print output,
return jitter.func_ret_stdcall(ret_addr, ret)
def xxx_strcpy(jitter):
ret_ad, args = jitter.func_args_stdcall(["dst", "src"])
str_src = jitter.get_str_ansi(args.src) + '\x00'
jitter.vm.set_mem(args.dst, str_src)
jitter.func_ret_stdcall(ret_ad, args.dst)
def xxx_strlen(jitter):
ret_ad, args = jitter.func_args_stdcall(["src"])
str_src = jitter.get_str_ansi(args.src)
jitter.func_ret_stdcall(ret_ad, len(str_src))
def xxx_malloc(jitter):
ret_ad, args = jitter.func_args_stdcall(["msize"])
addr = linobjs.heap.alloc(jitter, args.msize)
jitter.func_ret_stdcall(ret_ad, addr)
def xxx_free(jitter):
ret_ad, args = jitter.func_args_stdcall(["ptr"])
jitter.func_ret_stdcall(ret_ad, 0)
def xxx_strcmp(jitter):
ret_ad, args = jitter.func_args_stdcall(["ptr_str1", "ptr_str2"])
s1 = jitter.get_str_ansi(args.ptr_str1)
s2 = jitter.get_str_ansi(args.ptr_str2)
jitter.func_ret_stdcall(ret_ad, cmp(s1, s2))
def xxx_strncmp(jitter):
ret_ad, args = jitter.func_args_stdcall(["ptr_str1", "ptr_str2", "size"])
s1 = jitter.get_str_ansi(args.ptr_str1, args.size)
s2 = jitter.get_str_ansi(args.ptr_str2, args.size)
jitter.func_ret_stdcall(ret_ad, cmp(s1, s2))
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