Re: buffer overrun in zlib 1.1.4

From: Thamer Al-Harbash (tmhat_private)
Date: Mon Feb 24 2003 - 10:36:34 PST

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    On Sat, 22 Feb 2003, Richard Kettlewell wrote:
    
    > There is an internal #define (HAS_vsnprintf) that causes it to use
    > vsnprintf() instead of vsprintf(), but this is not enabled by default,
    > not tested for by the configure script, and not documented.
    
    This is a fairly normal (and somewhat frightening) practice I've
    seen in several popular packages.
    
    Last I checked ISC dhcp has a #define for vsnprintf to be
    vsprintf if the UNIX flavor did not support snprintf.
    
    medusa: {29} cd dhcp-3.0pl2
    medusa: {30} grep sprintf `find . -name "*.h"` | tail -10
    ./includes/cf/qnx.h:# define vsnprintf( buf, size, fmt, list )  vsprintf( buf, fbuf, list )
    ./includes/cf/sample.h:   sprintf functions which will deposit a limited number of characters
    ./includes/cf/sample.h:#define vsnprintf(buf, size, fmt, list) vsprintf (buf, fmt, list)
    ./includes/cf/sco.h:/* SCO doesn't support limited sprintfs. */
    ./includes/cf/sco.h:#define vsnprintf(buf, size, fmt, list) vsprintf (buf, fmt, list)
    ./includes/cf/sunos4.h:/* SunOS doesn't support limited sprintfs. */
    ./includes/cf/sunos4.h:#define vsnprintf(buf, size, fmt, list) vsprintf (buf, fmt, list)
    ./includes/cf/sunos5-5.h:/* Solaris doesn't support limited sprintfs. */
    ./includes/cf/sunos5-5.h:#define vsnprintf(buf, size, fmt, list) vsprintf (buf, fmt, list)
    ./includes/cf/ultrix.h:#define vsnprintf(buf, size, fmt, list) vsprintf (buf, fmt, list)
    
    I know that Ted Lemon, the primary author, is aware this. I've
    mentioned it to him a while ago. I am also not aware of this
    causing any security holes; although I honestly have not given
    his source a security audit.
    
    There are replacement 'snprintf' packages which avoid
    this. Patrick Powell's replacement is used in Mutt (a popular
    MUA) and has a very liberal license.
    
    -- 
    Thamer Al-Harbash            http://www.whitefang.com/
              team dresch made me do it
    



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