Re: Linux 5.1-rc2

[Casey Schaufler]

On 3/27/2019 3:05 PM, Tetsuo Handa wrote:
> On 2019/03/28 6:43, Kees Cook wrote:
> > > > I don't see problems for an exclusive LSM user (AA, SELinux, Smack)
> > > > also initializing TOMOYO, though. It should be a no-op. Is there some
> > > > situation where this is not true?
> > > There should be no problem except some TOMOYO messages are printed.
> > Okay, so I should send my latest version of the patch to James? Or do
> > you explicitly want TOMOYO removed from all the CONFIG_LSM default
> > lines except when selected by CONFIG_DEFAULT_SECURITY_TOMOYO? (I worry
> > the latter will lead to less testing of the stacking.)
> My approach is "opt-in" while your approach is "opt-out". And the problem
> here is that people might fail to change CONFIG_LSM from the default value
> to what they need. (And Jakub did not change CONFIG_LSM to reflect
> CONFIG_DEFAULT_SECURITY_APPARMOR from the old config.) Thus, I suggest
> "opt-in" approach; which includes up to only one legacy major LSM and allows
> people to change the default value to include multiple legacy major LSMs.
>
> You can propose your latest version. If SELinux/Smack/AppArmor people
> prefer "opt-out" approach, I'm fine with "opt-out" approach.

In the long haul we want people to use CONFIG_LSM to set their
list of modules. Providing a backward compatible CONFIG_DEFAULT_SECURITY_BLAH
makes some sense, but it's important that we encourage a mindset change.
Maybe with CONFIG_DEFAULT_SECURITY_LIST with a a full list, which uses the
value from CONFIG_LSM, and make it the default?