Re: [PATCH -v1 1/3] SECURITY: new capable_noaudit interface

Paul Moore
2008-10-30T17:30:54Z

On Thursday 30 October 2008 1:17:32 pm Eric Paris wrote:
> On Thu, 2008-10-30 at 12:46 -0400, Paul Moore wrote:
> > On Thursday 30 October 2008 11:29:40 am Serge E. Hallyn wrote:
> > > Quoting Eric Paris (eparis@redhat.com):
> > > > Add a new capable interface that will be used by systems that
> > > > use audit to make an A or B type decision instead of a security
> > > > decision. Currently this is the case at least for filesystems
> > > > when deciding if a process can use the reserved 'root' blocks
> > > > and for the case of things like the oom algorithm determining
> > > > if processes are root processes and should be less likely to be
> > > > killed. These types of security system requests should not be
> > > > audited or logged since they are not really security decisions.
> > > > It would be possible to solve this problem like the
> > > > vm_enough_memory security check did by creating a new LSM
> > > > interface and moving all of the policy into that interface but
> > > > proves the needlessly bloat the LSM and provide complex
> > > > indirection.
> > > >
> > > > This merely allows those decisions to be made where they belong
> > > > and to not flood logs or printk with denials for thing that are
> > > > not security decisions.
> > > >
> > > > Signed-off-by: Eric Paris <eparis@redhat.com>
> > >
> > > Please introduce some meaningful defines instead of passing 0 and
> > > 1. I.e.
> > >
> > > #define CAP_NOAUDIT 0
> > > #define CAP_AUDIT 1
> > >
> > > Otherwise, looks fine.
> >
> > As a general rule aren't boolean arguments like this frowned upon,
> > with variations on the function preferred, i.e. something like
> > below?
> >
> > int cap_capable(struct task_struct *tsk, int cap);
> > int cap_capable_audit(struct task_struct *tsk, int cap);
>
> Well from outside the "security" subsystem people should call either
>
> has_capability()
> has_capability_noaudit()
> or
> capable() (which calls has_capability())
>
> How far down do I have to keep duplicating functionality to avoid
> booleans?

Probably not this far :) Sorry, reading mail too quickly ...

--
paul moore
linux @ hp