On Mon, Oct 1, 2018 at 3:20 PM, John Johansen
<john.johansen@xxxxxxxxxxxxx> wrote:
> On 10/01/2018 02:56 PM, Kees Cook wrote:
>> On Mon, Oct 1, 2018 at 2:47 PM, James Morris <jmorris@xxxxxxxxx> wrote:
>>> On Mon, 24 Sep 2018, Kees Cook wrote:
>>>
>>>> In preparation for lifting the "is this LSM enabled?" logic out of the
>>>> individual LSMs, pass in any special enabled state tracking (as needed
>>>> for SELinux, AppArmor, and LoadPin). This should be an "int" to include
>>>> handling any future cases where "enabled" is exposed via sysctl which
>>>> has no "bool" type.
>>>>
>>>> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
>>>> ---
>>>> include/linux/lsm_hooks.h | 1 +
>>>> security/apparmor/lsm.c | 5 +++--
>>>> security/selinux/hooks.c | 1 +
>>>> 3 files changed, 5 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
>>>> index 5056f7374b3d..2a41e8e6f6e5 100644
>>>> --- a/include/linux/lsm_hooks.h
>>>> +++ b/include/linux/lsm_hooks.h
>>>> @@ -2044,6 +2044,7 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count,
>>>> struct lsm_info {
>>>> const char *name; /* Populated automatically. */
>>>> unsigned long flags; /* Optional: flags describing LSM */
>>>> + int *enabled; /* Optional: NULL means enabled. */
>>>
>>> This seems potentially confusing.
>>>
>>> Perhaps initialize 'enabled' to a default int pointer, like:
>>>
>>> static int lsm_default_enabled = 1;
>>>
>>> Then,
>>>
>>> DEFINE_LSM(foobar)
>>> flags = LSM_FLAG_LEGACY_MAJOR,
>>> .enabled = &lsm_default_enabled,
>>> .init = foobar_init,
>>> END_LSM;
>>
>> The reason I didn't do this is because there are only two LSMs that
>> expose this "enabled" variable, so I didn't like making the other LSMs
>> have to declare this. Internally, though, this is exactly what the
>> infrastructure does: if it finds a NULL, it aims it at
>> &lsm_default_enabled (in a later patch).
>>
>> However, it seems more discussion is needed on the "enable" bit of
>> this, so I'll reply to John in a moment...
>>
> fwiw the apparmor.enabled config is really only a meant to be used to
> disable apparmor. I'd drop it entirely except its part of the userspace
> api now and needs to show up in
>
> /sys/module/apparmor/parameters/enabled
Showing the enabled-ness there can be wired up. What should happen if
someone sets apparmor.enabled=0/1 in new-series-world? (See other
thread...)
-Kees
--
Kees Cook
Pixel Security
