Messages in this thread | | | From | Kees Cook <> | Date | Thu, 13 Sep 2018 16:51:43 -0700 | Subject | Re: [PATCH 10/10] LSM: Blob sharing support for S.A.R.A and LandLock |
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On Thu, Sep 13, 2018 at 4:32 PM, John Johansen <john.johansen@canonical.com> wrote: > On 09/13/2018 04:06 PM, Kees Cook wrote: >> - what order should any stacking happen? Makefile? security=? >> > Preferably not. For the single LSM we have the ability to choose the default LSM, ideally we let the distro decide in the Kconfig and the user with security=...
I can't find a non-crazy way to do this in Kconfig. Right now, if I threw out all the _DEFAULT stuff, I could do:
config SECURITY_SELINUX_ENABLED bool "SELinux LSM enabled at boot time" depends on SECURITY_SELINUX depends on !SECURITY_APPARMOR_ENABLED && !SECURITY_SMACK_ENABLED default SECURITY_SELINUX
config SECURITY_SMACK_ENABLED bool "SMACK LSM enabled at boot time" depends on SECURITY_SMACK depends on !SECURITY_APPARMOR_ENABLED && !SECURITY_SELINUX_ENABLED default SECURITY_SMACK
config SECURITY_APPARMOR_ENABLED bool "AppArmor LSM enabled at boot time" depends on SECURITY_APPARMOR depends on !SECURITY_SMACK_ENABLED && !SECURITY_SELINUX_ENABLED default SECURITY_APPARMOR
config SECURITY_TOMOYO_ENABLED bool "TOMOYO LSM enabled at boot time" depends on SECURITY_TOMOYO default y if !SECURITY_SELINUX_ENABLED && !SECURITY_SMACK_ENABLED && !SECURITY_APPARMOR_ENABLED
config DEFAULT_SECURITY string default "selinux" if SECURITY_SELINUX_ENABLED default "smack" if SECURITY_SMACK_ENABLED default "apparmor" if SECURITY_APPARMOR_ENABLED default "tomoyo" if SECURITY_TOMOYO_ENABLED
(As before CONFIG_DEFAULT_SECURITY basically means the effective "security=" contents. Reminder than Kconfig default are "first match", so tomoyo would only happen if all others are not enabled by default.)
But this doesn't provide a way for Kconfig to declare the ordering of TOMOYO followed by SELinux. If we just declare ordering is a function of the Makefile, then the above would work as expected. The "conflicting major LSM" could be specified on "security=" and stacked could be enabled with $lsm.enable=1 (or disabled).
So, before we can really make a decision, I think we have to decide: should ordering be arbitrary for even this level of stacking?
-Kees
-- Kees Cook Pixel Security
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