Re: [PATCH v3 1/1] x86: allow to enable/disable modify_ldt at run time

[Willy Tarreau]

Hi Ingo,

On Wed, Aug 05, 2015 at 10:00:37AM +0200, Ingo Molnar wrote:
> 
> * Willy Tarreau <w@xxxxxx> wrote:
> 
> > @@ -276,6 +282,15 @@ asmlinkage int sys_modify_ldt(int func, void __user *ptr,
> >  {
> >  	int ret = -ENOSYS;
> >  
> > +	if (!sysctl_modify_ldt) {
> > +		printk_ratelimited(KERN_INFO
> > +			"Denied a call to modify_ldt() from %s[%d] (uid: %d)."
> > +			" Adjust sysctl if this was not an exploit attempt.\n",
> > +			current->comm, task_pid_nr(current),
> > +			from_kuid_munged(current_user_ns(), current_uid()));
> 
> UI nit: so this message should really tell the user _which_ sysctl to configure, 
> instead of passive-aggressively alluding to the fact that there's a sysctl 
> somewhere that might do the trick...

I agree, I did it first and changed my mind due to the repetition of
the word "modify_ldt".

Here's an updated version instead.

Willy