RE: FW: i386 Linux kernel DoS (clarification)

[Alan Cox]

On Wed, 2002-11-13 at 21:18, Petr Vandrovec wrote:
> >     pushfl          # We get a different stack layout with call
> >                 # gates, which has to be cleaned up later..
> > +   andl $~0x4500, (%esp)   # Clear NT since we are doing an iret
> 
> this will clear 'D' and 'T' in caller after we do
> iret (if lcall7 returns, of course). I'm not sure that callers

You can adjust that if you want, I copied it about - clearing D is fine,
in fact it may let us avoid the cld

> >  error_code:
> > +   pushfl
> > +   andl $~0x4500, (%esp)       # NT must be clear, do a cld for free
> > +   popfl
> 
> I believe that NT should be automagically cleared by int.

Apparently so - you are I think 100% correct that this isnt needed