Re: Possible "struct pid" leak from tty_io.c

From: Eric W. Biederman
Date: Mon Mar 12 2007 - 12:13:27 EST


"Catalin Marinas" <catalin.marinas@xxxxxxxxx> writes:

> On 09/03/07, Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote:
>> If I can manage to focus on this, it looks like the information I need to
>> start fixing this.
>
> I had a look at the second leak reported it seems to be caused by the
> same proc_set_tty() call but, in this case, there is no
> disassociate_tty() call for the task (and the patch I posted is not
> enough). Maybe something like below (no thourough testing):

Thanks. That doesn't look to bad. I'm just about to look into this.
If I'm lucky all I will need to do is a close code review of your
patch.

Hopefully I can do that this afternoon.

> diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
> index db91398..ea6ca7d 100644
> --- a/drivers/char/tty_io.c
> +++ b/drivers/char/tty_io.c
> @@ -3854,7 +3854,14 @@ EXPORT_SYMBOL(tty_devnum);
>
> void proc_clear_tty(struct task_struct *p)
> {
> + struct tty_struct *tty;
> +
> spin_lock_irq(&p->sighand->siglock);
> + tty = p->signal->tty;
> + if (tty) {
> + put_pid(tty->session);
> + put_pid(tty->pgrp);
> + }
> p->signal->tty = NULL;
> spin_unlock_irq(&p->sighand->siglock);
> }

Eric
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