Buffer-overflow in the XM loader of Cheese Tracker 0.9.9

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Luigi Auriemma

Application:  Cheese Tracker
              http://reduz.com.ar/cheesetracker/
              http://sourceforge.net/projects/cheesetronic
Versions:     <= 0.9.9 and current CVS
Platforms:    *nix and others
Bug:          buffer-overflow in Loader_XM::load_instrument_internal
Exploitation: local
Date:         23 Jul 2006
Author:       Luigi Auriemma
              e-mail: aluigi (at) autistici (dot) org [email concealed]
              web:    aluigi.org

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1) Introduction
2) Bug
3) The Code
4) Fix

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===============
1) Introduction
===============

Cheese Tracker is a well known music tracker for the CT, IT, XM and S3M
file formats.

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======
2) Bug
======

The XM loader used by Cheese Tracker is affected by a buffer-overflow
vulnerability which happens when it tries to store the exceeding data
available in the input file in the junkbuster buffer of only 500 bytes.

From cheesetracker/loaders/loader_xm.cpp:

Loader::Error Loader_XM::load_instrument_internal(Instrument *p_instr,bool p_xi,int p_cpos, int p_hsize, int p_sampnum) {
        ...
        if (!p_xi) {

if ((reader.get_file_pos()-p_cpos)<p_hsize) {

Uint8 junkbuster[500];

//printf("extra junk XM instrument in header! hsize is %i, extra junk: %in",p_hsize,(reader.get_file_pos()-p_cpos));

reader.get_byte_array((Uint8*)junkbuster,p_hsize-(reader.get_file_pos()-
p_cpos));
            }
            ...

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===========
3) The Code
===========

http://aluigi.org/poc/cheesebof.zip

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4) Fix
======

No fix.
No reply from the developers.

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--- 
Luigi Auriemma
http://aluigi.org
http://mirror.aluigi.org

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