Re: [RFC PATCH 1/4] lsm: separate security_task_getsecid() into subjective and objective variants

[Paul Moore <paul@paul-moore.com>]

On Wed, Mar 3, 2021 at 7:44 PM Paul Moore <paul@paul-moore.com> wrote:
> On Sun, Feb 21, 2021 at 7:51 AM John Johansen
> <john.johansen@canonical.com> wrote:
> > On 2/19/21 3:29 PM, Paul Moore wrote:
> > > Of the three LSMs that implement the security_task_getsecid() LSM
> > > hook, all three LSMs provide the task's objective security
> > > credentials.  This turns out to be unfortunate as most of the hook's
> > > callers seem to expect the task's subjective credentials, although
> > > a small handful of callers do correctly expect the objective
> > > credentials.
> > >
> > > This patch is the first step towards fixing the problem: it splits
> > > the existing security_task_getsecid() hook into two variants, one
> > > for the subjective creds, one for the objective creds.
> > >
> > >   void security_task_getsecid_subj(struct task_struct *p,
> > >                                  u32 *secid);
> > >   void security_task_getsecid_obj(struct task_struct *p,
> > >                                 u32 *secid);
> > >
> > > While this patch does fix all of the callers to use the correct
> > > variant, in order to keep this patch focused on the callers and to
> > > ease review, the LSMs continue to use the same implementation for
> > > both hooks.  The net effect is that this patch should not change
> > > the behavior of the kernel in any way, it will be up to the latter
> > > LSM specific patches in this series to change the hook
> > > implementations and return the correct credentials.
> > >
> > > Signed-off-by: Paul Moore <paul@paul-moore.com>
> >
> > So far this looks good. I want to take another stab at it and give
> > it some testing
>
> Checking in as I know you said you needed to fix/release the AppArmor
> patch in this series ... is this patch still looking okay to you?  If
> so, can I get an ACK at least on this patch?

Hi John,

Any objections if I merge the LSM, SELinux, and Smack patches into the
selinux/next tree so that we can start getting some wider testing?  If
I leave out my poor attempt at an AppArmor patch, the current in-tree
AppArmor code should behave exactly as it does today with the
apparmor_task_getsecid() function handling both the subjective and
objective creds.  I can always merge the AppArmor patch later when you
have it ready, or you can merge it via your AppArmor tree at a later
date.

-- 
paul moore
www.paul-moore.com