[refpolicy] [PATCH 2/2] system/modutils: Allow kmod to use the sys_admin cap

[guido@trentalancia.net (Guido Trentalancia)]

On Sun, 28/11/2016 at 23.14 +0100, Luis Ressel wrote:
> On Mon, 28 Nov 2016 22:57:40 +0100
> Guido Trentalancia via refpolicy <refpolicy@oss.tresys.com> wrote:
> 
> > 
> > That's really?counterproductive when combined with SELinux !
> > 
> > At the moment, if a malicious version of getty gets into the
> > system,
> > it is granted sys_admin capability permissions (which includes
> > privileged and administrative operations).
> > 
> > On the other hand, a normal, tight policy (which does not grant the
> > unneeded sys_admin permission) would prevent a malicious getty from
> > carrying out privileged and administrative operations which can
> > damage
> > the system and/or disrupt its normal operation.
> 
> Well, a malicious binary tagged getty_t and running with root
> privileges could easily wreak enough havoc that the availability or
> non-availability of CAP_SYS_ADMIN access is somewhat irrelevant.
> 
> Anyway, I've just revisited the discussion about agetty's
> cap_sys_admin
> permission we've had in March. Looks like it may be required on some
> non-grsec systems, too. (Grep the ML history for the subject "Allow
> getty the sys_admin capability").

It's very easy !...

You can create a patch that reverts
commit?7216d000d94342dc347a976a7a6a65f40a2f41cb and then adds an "ifdef
grsecurity" for such sys_admin permission (for getty and/or kmod).

That way, it won't unnecessarily weaken other systems.

Regards,

Guido