Re: [RFC PATCH v2] selinux: security: Move selinux_state to a separate page

[pnagar]

On 2021-01-09 06:31, Nick Desaulniers wrote:
> Via:
> https://lore.kernel.org/lkml/1610099389-28329-1-git-send-email-pnagar@xxxxxxxxxxxxxx/
>
> > diff --git a/include/linux/init.h b/include/linux/init.h
> > index 7b53cb3..617adcf 100644
> > --- a/include/linux/init.h
> > +++ b/include/linux/init.h
> > @@ -300,6 +300,10 @@ void __init parse_early_options(char *cmdline);
> >  /* Data marked not to be saved by software suspend */
> >  #define __nosavedata __section(".data..nosave")
> >
> > +#ifdef CONFIG_SECURITY_RTIC
> > +#define __rticdata  __section(".bss.rtic")
>
> if you put:
>
> #else
> #define __rticdata
>
> here, then you wouldn't need to label each datum you put in there.
>
> > +#endif
> > +
> >  #ifdef MODULE
> >  #define __exit_p(x) x
> >  #else
>
> > --- a/security/selinux/hooks.c
> > +++ b/security/selinux/hooks.c
> > @@ -104,7 +104,11 @@
> >  #include "audit.h"
> >  #include "avc_ss.h"
> >
> > +#ifdef CONFIG_SECURITY_RTIC
> > +struct selinux_state selinux_state __rticdata;
> > +#else
> >  struct selinux_state selinux_state;
> > +#endif
>
> so you could then drop the if-def here.
Will update this in next version, thank you for the suggestion.

> Happy to see this resolved when building with LLD+LTO, which has been a
> problem in the past.
Yes, downstream we have this verified with LTO configs enabled. Let us 
know if
you are suggesting to check anything additionally here.

> Disabling selinux is a common attack vector on Android devices, so 
> happy
> to see some effort towards mitigation.  You might want to communicate
> the feature more to existing OEMs that are using your chipsets that
> support this feature.
Glad to know the idea looks good! Yes, we will work on that, will 
communicate
internally as well, thank you.