linux-kernel - Re: [PATCH v2] MODSIGN: Only sign modules if built in-tree

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Date:	Tue, 6 Nov 2012 07:54:17 -0500
From:	Josh Boyer <jwboyer@...hat.com>
To:	Rusty Russell <rusty@...tcorp.com.au>
Cc:	Bruno Wolff III <bruno@...ff.to>, dhowells@...hat.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] MODSIGN: Only sign modules if built in-tree

On Tue, Nov 06, 2012 at 12:04:02PM +1030, Rusty Russell wrote:
> Josh Boyer <jwboyer@...hat.com> writes:
> > On Mon, Nov 05, 2012 at 12:31:39PM +1030, Rusty Russell wrote:
> >> Josh Boyer <jwboyer@...hat.com> writes:
> >> > diff --git a/Makefile b/Makefile
> >> > index 14c93b3..7e27d51 100644
> >> > --- a/Makefile
> >> > +++ b/Makefile
> >> > @@ -722,8 +722,14 @@ export mod_strip_cmd
> >> >  ifeq ($(CONFIG_MODULE_SIG),y)
> >> >  MODSECKEY = ./signing_key.priv
> >> >  MODPUBKEY = ./signing_key.x509
> >> > +ifeq ($(KBUILD_EXTMOD),)
> >> > +SIGNFAIL = false
> >> > +else
> >> > +# External builds might not have a signing key, don't break module_install.
> >> > +SIGNFAIL = true
> >> > +endif # KBUILD_EXTMOD
> >> >  export MODPUBKEY
> >> > -mod_sign_cmd = perl $(srctree)/scripts/sign-file $(MODSECKEY) $(MODPUBKEY)
> >> > +mod_sign_cmd = $(SIGNFAIL) || perl $(srctree)/scripts/sign-file $(MODSECKEY) $(MODPUBKEY)
> >> >  else
> >> >  mod_sign_cmd = true
> >> >  endif
> >> 
> >> Huh?  'true || perl' never runs perl due to short circuiting.
> >
> > Ah.  Maybe you were going for "sign all modules if keys are available,
> > but don't break external if they aren't" semantics.  I was just skipping
> > it entirely for external modules.
> 
> Exactly.  This way you get warnings, not failure.  You probably want
> that, since you'll (at least) taint your kernel when you load those
> modules.
> 
> I've applied this in my fixes branch, will push to Linus later this
> week.

Great.  Thanks Rusty!

josh
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