Hi. I'm wondering if anyone has any input on this. After building the Fedora SELinux policy with UBAC support (and rebooting), I've created two SELinux users: {user_a role_a type_a} and {user_b role_b type_b}, and both type_a and type_b have the ubac_constrained_type attribute set. My understanding of UBAC led me to believe that user_a would not have access to a file of type type_b. Similarly, user_b would not have access to a file of type type_a. However, these accesses are allowed. What else do I need to do to get this to work. Thanks.
-jeffOn Fri, Nov 11, 2016 at 4:29 PM, Jeff Becker <jeff.c.becker@xxxxxxxxx> wrote:
Some progress...
On Thu, Nov 10, 2016 at 8:48 AM, Jeff Becker <jeff.c.becker@xxxxxxxxx> wrote:Hi.On Thu, Nov 10, 2016 at 5:25 AM, Miroslav Grepl <mgrepl@xxxxxxxxxx> wrote:On 11/09/2016 08:54 PM, Jeff Becker wrote:
> Hi. I successfully compiled and loaded the following policy file on
> RHEL7 with the latest (as of yesterday) SELinux rpms. However, when I
> run "seinfo -tfoo_t -x", I don't see ubac_constrained_type listed in the
> attributes. How do I enable UBAC? Thanks.
Hi Jeff,
we don't build Fedora/RHEL distribution policy with UBAC support.I suspected that.
You
would need to rebuild the policy from srpms to enable itI grabbed selinux-policy-3.13.1-103.fc22.src.rpm from http://kojipkgs.fedoraproject. org . I figured this was close to what I have installed (selinux-policy-3.13.1-102.el7_3.4.noarch). I enabled UBAC in build.conf, and built and installed the policy. When I rebooted, I could see that ubac_constrained_type attribute was present on several types (including my new ones that I recompiled and loaded). However, it's not working the way I thought it should. If I log in with SELinux user A and I try to access a file from SELinux user B (both types have ubac_constrained_type attribute set), I thought access would be denied, but it's not, and nothing shows up in the audit log. Am I misunderstanding or missing something? Thanks. -jeff
What is your intention with UBAC?My use case is that I'd like to have several file types with associated SELinux users/roles, such that SELinux users of a certain type cannot access files associated with another user's type, regardless of what application is used for the access, e.g., my foo_u user below would not be able to access files of type bar_t (associated with SELinux user bar_u). I need this to be under mandatory access control, so it seems that multi category security (MCS) labels would not work, as they are discretionary. Is there another way, e.g., role based access control (RBAC) that could be used? Thanks.-jeff
>
> -jeff
>
> ------------------------------------------------------------ ------------------------------ ------------------------------ ------------------------------ --------
>
> policy_module(foo, 1.0.0)
>
> ########################################
> #
> # Declarations
> #
> userdom_unpriv_user_template(foo)
>
> ########################################
> #
> # foo local policy
> #
>
> domain_use_interactive_fds(foo_t)
>
> files_read_etc_files(foo_t)
>
> miscfiles_read_localization(foo_t)
>
> ubac_constrained(foo_t)
>
>
>
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>
--
Miroslav Grepl
Senior Software Engineer, SELinux Solutions
Red Hat, Inc.
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