Vulnerability Development: Re: argc issue

[Valdis.Kletnieks () vt edu]

On Tue, 23 May 2006 19:51:58 +0200, padre () correo ugr es said:

>  if (argc)
>     exit (-1);
>  else {
>       strcpy(a,argv[1]);
>       }
Buggy code.  It's basically saying "If there's arguments to the program,
exit. Otherwise, copy the (implicitly non-existent) first argument to 'a'".

> But the main issue is " if (argc) exit(0);" . How can I change the argc
> variable so it contais the value of 0?.
Fix your code, I think you wanted 'if (!argc) exit (-1);'

That's probably easier than trying to over-ride the system startup code
that creates the argc value and passes it to main() (on Linux/Unix boxes,
usually in a stub called crt0.o or similar).  Lots of tricky system-dependent
code in there, it's not for the faint of heart.

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