Re: argc issue

the trick here is to use a wrapper program to that calls the executable 
without *any arguments* including argv[0]


at that point argc == 0 argv[0] == NULL
and argv[1] is somewhere in the the environmental variables..

and.. as an asside, when playing wargames.. its usually best not to cheat or 
you really get nothing out of it.

-phar
----- Original Message ----- 
From: <[email protected]>
To: <[email protected]>
Sent: Tuesday, May 23, 2006 1:51 PM
Subject: argc issue


hi!

i' ve a code thats looks like:

------------------- code ----------------------
int main (int argc, char **argv)
{
char *a;
char *b;

a=malloc(char *)(100);
b=malloc(char *)(100);

 if (argc)
    exit (-1);
 else {
      strcpy(a,argv[1]);
      }

free (a);

return 0;
}

---------------- code ---------------------------

I contais an explotable heap overflow. I can overwrite b's chunk head so I
can write into DTOR_END the addr i want.

But the main issue is " if (argc) exit(0);" . How can I change the argc
variable so it contais the value of 0?.

thanks and srry for my poor english :(