In article <201805172011.qaa05...@stone.rodents-montreal.org>,
Mouse <mo...@rodents-montreal.org> wrote:
>In sys/kern/tty.c, I find
>
> case FIOSETOWN: { /* set pgrp of tty */
>[...]
> if (tp->t_session != NULL && !isctty(p, tp)) {
> mutex_exit(proc_lock);
> return (ENOTTY);
> }
>
>and
>
> case TIOCSPGRP: { /* set pgrp of tty */
>[...]
> if (!isctty(p, tp)) {
> mutex_exit(proc_lock);
> return (ENOTTY);
> }
>
>These are being a problem for me; I want to open up two ttys, neither
>being my control tty, and get SIGIO when I/O is possible on either.
>Obviously, I can just build a kernel with those tests snipped out;
>indeed, I'm doing exactly that to see if my code works then.
>
>But I'm wondering why those checks are there, wondering what hazard I'm
>risking by removing them. Anyone happen to know?
It is a security issue (as usual).
christos
