Re: + make-good_sigevent-non-static.patch added to -mm tree

[Sébastien Dugué <sebastien.dugue@bull.net>]

On Thu, 25 Jan 2007 18:43:24 +0300 Oleg Nesterov <oleg@tv-sign.ru> wrote:

> SИbastien DuguИ wrote:
> >
> > +struct task_struct *good_sigevent(sigevent_t *event)
> > +{
> > +	struct task_struct *task = current->group_leader;
> > +
> > +	if ((event->sigev_notify & SIGEV_THREAD_ID) == SIGEV_THREAD_ID) {
> > +		task = find_task_by_pid(event->sigev_notify_thread_id);
> > +
> > +		if (!task || task->tgid != current->tgid)
> > +			return NULL;
> > +	} else if (event->sigev_notify == SIGEV_SIGNAL) {
> 
> No, no, we can't use "else" here,
> 
> > +		if (event->sigev_signo <= 0 || event->sigev_signo > SIGRTMAX)
> 
> because we skip the check above in SIGEV_THREAD_ID case.

  Right, will fix this.

> 
> This way any user can crash the kernel with a minimal effort.

  Well I tried, no crash, just the signal failing to be delivered.

  Thanks,

  Sébastien.
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