On Sat, 2014-06-28 at 01:20 -0400, Yassir Elley wrote:
----- Original Message -----
> On Thu, 2014-06-26 at 04:54 -0400, Yassir Elley wrote:
> > Hi Simo,
> > I'd like to wrap up this discussion. I propose that we support only
> > the InteractiveLogonRight (for the pam services you mentioned:
> > "login", "*dm, "su*"), and on the
RemoteInteractiveLogonRight (for the
> > "ssh" pam service). We should not support the NetworkLogonRight
> > it is difficult to implement. Do you agree with this proposal?
> Well I guess the answer depends on what do you plan to do for pam
> services that are not listed ?
> Do you always deny access ? Always permit ?
Since we would only support the InteractiveLogonRight and RemoteInteractiveLogonRight, we
would always permit access for other pam services (because they would not be governed by
gpo-based access control, and this would be clearly documented).
> I think a more reasonable workaround is to define a default type, and a
> list of mappings.
> If a PAM service is explicitly mapped you use that Right to decide,
> otherwise the decision falls back to the "default" Right.
> Actually the default right could well be actually NetworkLogonRight or
> InteractiveLogonRight or something else. As long as you can change the
> mappings locally through some configuration that would allow the admin
> to add mappings according to their needs. Of course strong guidance
> on which mappings should be used for specific type of services should be
I would prefer an approach which is more predictable for the AD admin. If we limit
ourselves to InteractiveLogonRight and RemoteInteractiveLogonRight, the semantics are very
clear (console login and remote login), allowing the AD Admin to be confident that any
existing or future policy files containing those rights would be applied correctly and
consistently, regardless of whether the machine is running Linux or Windows.
Also, I suspect AD admins would not like per-machine service mappings to be enforced,
since that would defeat the purpose of enforcing a centralized policy in a consistent
manner. When an AD admin made a change to a LogonRight policy setting, he would have to
keep in mind that Linux machines may use the policy settings in ways that were not
intended by the AD admin. For example, it would be problematic if a local admin decided to
map "login" to NetworkLogonRight, or if some local admins mapped "ftp"
to some LogonRight (but other local admins stayed with the default). This would result in
inconsistent behavior between different Linux machines, and between Linux machines and
Windows machines. Indeed, in the Windows world, the "local" per-machine GPO is
given least priority in case of conflict (i.e. ou overrides domain, which overrides site,
which overrides local). A solution to this problem of consistency would be to have a
centralized GPO that maps pam services to LogonRights, but I don't think we need to
implement that in the first release.
I think limiting ourselves to InteractiveLogonRight and RemoteInteractiveLogonRight would
be less confusing and more predictable for AD admins (resulting in a greater likelihood of
them deploying gpo-based access control). They would know that these two LogonRights would
be enforced with the same semantics on Windows and Linux machines. They would also know
that other LogonRights would not be enforced on Linux machines. Clean and crisp.
What do you think?
You make a good argument, but I am not entirely convinced you can avoid
a local mapping unless you provide a GPO mapping, because the admin must
be able to adjust mappings for new services installed on the box that
were not included in the upstream provided lists.
So if you already need to provide a way to augment mappings, you may as
well handle all rights with reasonable defaults, and let the admin
decide whether they need to change stuff around.
Simo Sorce * Red Hat, Inc * New York