Re: [PATCH security-next v4 23/32] selinux: Remove boot parameter

[Stephen Smalley]

On 10/02/2018 07:54 PM, Kees Cook wrote:
> On Tue, Oct 2, 2018 at 4:46 PM, John Johansen
> <john.johansen@xxxxxxxxxxxxx> wrote:
> > On 10/02/2018 04:06 PM, Kees Cook wrote:
> > > I think the current proposal (in the other thread) is likely the
> > > sanest approach:
> > >
> > > - Drop CONFIG_SECURITY_SELINUX_BOOTPARAM_VALUE
> > > - Drop CONFIG_SECURITY_APPARMOR_BOOTPARAM_VALUE
> > > - All enabled LSMs are listed at build-time in CONFIG_LSM_ENABLE
> >
> > Hrrmmm isn't this a Kconfig selectable list, with each built-in LSM
> > available to be enabled by default at boot.
>
> That's not how I have it currently. It's a comma-separated a string,
> including the reserved name "all". The default would just be
> "CONFIG_LSM_ENABLE=all". Casey and I wanted this to have a way to
> capture new LSMs by default at build-time.
>
> > > - Boot time enabling for selinux= and apparmor= remain
> > > - lsm.enable= is explicit: overrides above and omissions are disabled
> > wfm
>
> Okay, this is closer to v3 than v4. Paul or Stephen, how do you feel
> about losing the SELinux bootparam CONFIG? (i.e. CONFIG_LSM_ENABLE
> would be replacing its functionality.)

I'd like to know how distro kernel maintainers feel about it. They would 
need to understand that if they were previously setting 
CONFIG_SECURITY_SELINUX_BOOTPARAM_VALUE to 0 and want to preserve that 
behavior, then they must set CONFIG_LSM_ENABLE explicitly to a list of 
security modules (that does not include selinux, of course).  In 
practice, this means that even the distros that choose to build all 
security modules into their kernels must explicitly set 
CONFIG_LSM_ENABLE to a specific list of security modules.  So no one 
would use "all" in practice.