Re: [PATCH 3/3 V13] RO/NX protection for loadable kernel

[matthieu castet]

This is a multi-part message in MIME format.Xiaotian Feng a Ãcrit :
> On Thu, Dec 23, 2010 at 5:35 AM,  <Valdis.Kletnieks@xxxxxx> wrote:
> > On Wed, 22 Dec 2010 13:40:19 +0100, Ingo Molnar said:
> > > * mat <castet.matthieu@xxxxxxx> wrote:
> > >
> > > > Le Wed, 8 Dec 2010 14:19:51 -0800,
> > > > Kees Cook <kees.cook@xxxxxxxxxxxxx> a Ãcrit :
> > > >
> > > > > On Fri, Nov 26, 2010 at 06:23:55PM +0100, mat wrote:
> > > > > > could you try the attached patch ?
> > > > > >
> > > > > > on module load, we sort the __jump_table section. So we should make
> > > > > > it writable.
> > > > > >
> > > > > >
> > > > > > Matthieu
> > > > > > diff --git a/arch/x86/include/asm/jump_label.h
> > > > > > b/arch/x86/include/asm/jump_label.h index f52d42e..574dbc2 100644
> > > > > > --- a/arch/x86/include/asm/jump_label.h
> > > > > > +++ b/arch/x86/include/asm/jump_label.h
> > > > > > @@ -14,7 +14,7 @@
> > > > > >         do
> > > > > > {                                                       \ asm
> > > > > > goto("1:"                                       \
> > > > > > JUMP_LABEL_INITIAL_NOP                  \
> > > > > > -                       ".pushsection __jump_table,  \"a\" \n\t"\
> > > > > > +                       ".pushsection __jump_table,  \"aw\" \n\t"\
> > > > > >                         _ASM_PTR "1b, %l[" #label "], %c0 \n\t" \
> > > > > >                         ".popsection \n\t"                      \
> > > > > >                         : :  "i" (key) :  : label);
> > > > > > \
> > > > > Acked-by: Kees Cook <kees.cook@xxxxxxxxxxxxx>
> > > > >
> > > > > Can this please get committed to tip?
> > > > I think it is not need anymore with  Steven Rostedt patch [1]
> > > >
> > > > Matthieu
> > > >
> > > > [1]
> > > > > > Here we set the text read only before we call the notifiers. The
> > > > > > function tracer changes the calls to mcount into nops via a notifier
> > > > > > call so this must be done after the module notifiers.
> > > What's the status of this bug?
> > >
> > > If we still need the patch then please submit it standalone with a proper subject
> > > line, with acks/signoffs added, etc.
> > Steve Rostedt's patch that moves the setting of the page permissions seems to
> > make this patch no longer necessary.  I tripped over this same issue, but the
> > version in the latest -mmotm does not need it, as it includes Steve's fix.
>
> I'm facing a boot failure (panic'ed on remove_jump_label_module_init)
> on 2.6.37 (latest commit 3c0cb7c), which is 100% reproducible.
> With this patch applied, I can boot my machine successfully, so I do
> think this patch is needed.
Could you confirm that this patch fix the problem ?


Matthieu