[Freeipa-users] RHEL6 IPA and Active Directory synchronisation and Solaris RBAC
Rodney L. Mercer
rmercer at harris.com
Tue Feb 19 14:14:21 UTC 2013
On Sun, 2013-02-17 at 13:31 -0500, Dmitri Pal wrote:
> On 02/16/2013 12:14 PM, Mercer, Rodney wrote:
> > ________________________________________
> > From: freeipa-users-bounces at redhat.com [freeipa-users-bounces at redhat.com] on behalf of Sigbjorn Lie [sigbjorn at nixtra.com]
> > Sent: Saturday, February 16, 2013 6:29 AM
> > To: freeipa-users at redhat.com
> > Subject: Re: [Freeipa-users] RHEL6 IPA and Active Directory synchronisation and Solaris RBAC
> >
> > On 02/15/2013 10:31 PM, Dmitri Pal wrote:
> >> On 02/15/2013 09:17 AM, Rodney L. Mercer wrote:
> >>> On Thu, 2013-02-14 at 21:44 +0100, Sigbjorn Lie wrote:
> >>>> I agree with schema support being enough for now. I do not expect the
> >>>> ipa mgmt tools to support Solaris rbac mgmt.
> >>>>
> >>>> The ipa mgmt tools are great, but I already have other data in the ipa
> >>>> ldap that I have to manage manually anyway.
> >>>>
> >>>>
> >>>>
> >>>> Rgds,
> >>>> Siggi
> >>>>
> >>>>
> >>>>
> >>>> Rob Crittenden <rcritten at redhat.com> wrote:
> >>>> Dag Wieers wrote:
> >>>> On Thu, 14 Feb 2013, Rob Crittenden wrote:
> >>>>
> >>>> Sigbjorn Lie wrote:
> >>>> On 02/13/2013 04:10 PM, Rob Crittenden wrote:
> >>>>
> >>>> Also since we also require compatibility with Solaris, and roles
> >>>> (RBAC)
> >>>> is currently used on Solaris, does IPA support RBAC on Solar
> >>>> is ?
> >>>> (We
> >>>> noticed that RBAC mentioned in the IPA web interface only
> >>>> relates to > > IPA
> >>>> management).
> >>>> No, IPA doesn't support RBAC on Solaris.
> >>>>
> >>>> I've come across the same issue. This is just a matter of extending the
> >>>> schema.
> >>>>
> >>>> Would there be any interest for adding the Solaris RBAC schema as a
> >>>> part
> >>>> of the standard IPA distributed LDAP schema?
> >>> Consider the following: What else would have to be put in to support
> >>> this?
> >>> Once the schema is established, can SSSD be extended to use this and
> >>> potentially be referenced in nsswitch.conf as it is implemented on
> >>> Solaris? IE:
> >>> tail -5 /etc/nsswitch.conf
> >>> user_attr: sssd
> >>> auth_attr: sssd
> >>> prof_attr: sssd
> >>> exec_attr: sssd
> >>> project: sssd
> >> Before we define how it is passed/exposed it would nice to understand
> >> who on Linux will be consuming it out of SSSD?
> >>
> > I don't think Linux would consume these attributes. They are specific to
> > the Role Based Access Control solution implemented in Solaris.
> >
> >
> > Rgds,
> > Siggi
> >
> > ----------------------------------
> >
> > Yes, I understand that Linux has no mechanism currently built in to consume these Solaris name server switch attributes. But, If the Solaris RBAC schema is included as
> > part of the standard IPA distributed LDAP schema, My question is how hard would it be to create an extension using SSSD/pam to do so?
> >
> > I agree that it is too much to ask for a full Solaris style RBAC implementation on RHEL.
> >
> > We have an application that currently uses the Solaris RBAC structure to authorize user/role accesses within the application.
> >
> > Our goal is to use existing OS calls or possibly extending SSSD to allow system calls that would give us back an answer to attrbutes placed within the LDAP
> > tree that are composed in like fashion as how they are stored in Solaris. Defining the schema seemed to be well received and I understand that it is intended that it would be there to support Solaris clients.
> > If SSSD could be extended to access these attributes and possibly pam modules to allow Linux clients to take advantage of this RBAC schema, then our application could perform as it does on Solaris. It would also
> > open up the opportunity for other vendors to consider moving their Solaris RBAC applications to RHEL.
> >
> > I think with that as a goal, we could then create users and SELinux roles that are defined within the RBAC based schema much like our current Solaris implementation.
> > We use Solaris nsswitch calls to get yes/no authorization answers for user/role privilege within our application.
> >
> > Since IdM and SSD already support
> > a) HBAC
> > b) SUDO
> > c) SELinux user mapping
> >
> > I believe HBAC as already implemented in IdM will be an additional asset in defining and restricting access that can be used by our customers.
> > We have decided to move away from sudo, but may reconsider some of its uses if it suits the situation.
> > Maybe SSSD can be extended to access the RBAC schema in much the same way that it accesses SUDO or HBAC schema?
> >
> > We have decided to use RHEL as the primary OS platform of choice going forward and we need to create a solution to our application RBAC
> > needs similar to that in which we have accomplished with Solaris. I have been speaking with Dmitri on the side about these possibilities and would like to know
> > what each of your thoughts are. The feasibility of accomplishing this is a bit over my head but is certainly our goal.
> > I believe our management is committed to creating such a solution by involving our software engineers. Helping with adding the Solaris RBAC schema and
> > contributing the GUI to manage the RBAC Schema data would be a goal.
> >
> > Also, since this is not the SSSD development list, I would like to know the list info for SSSD development and see what their thoughts are.
> >
> > Dmitri to answer your questions directly to me:
> > Certainly we can discuss additional security components such as centrally managed SSH keys and host fingerprints. We don't need any interaction within our application to include AD,
> > but our customers may want to take advantage of that at some point.
> The sssd user list is
>
> sssd-users at lists.fedorahosted.org
>
> The devel list is
> sssd-devel at lists.fedorahosted.org
>
>
> But I suggest we continue this conversation here because otherwise the
> conversation might fork and I would be hard to track. Most of the SSSD
> developers read this list too.
>
> Since you have a clearly defined interface your application consumes
> from Solaris the best thing now would be for you to provide a man page
> style description of the calls the application needs and we will see how
> to satisfy them with what we have and identify what needs to be added.
> IMO such interface would be a requirement list. How we deliver it to the
> application is an important but yes an implementation detail that we can
> discuss after we know what requirements are.
>
Dmitri,
We only use one system call from our application. that is
chkauthattr - get authorization entry
http://www.unix.com/man-page/all/3secdb/chkauthattr/
we have users and roles defined in the user_attr map
Each user is assigned one or more profiles.
The profiles are kept in the prof_attr map.
Top level Profiles can and often are mapped to groups of "sub" profiles,
where each of the "sub" profiles are mapped to groups of authorizations.
The authorizations are stored in the auth_attr map and map to strings
that our application queries to determine if the user/role has mapped
to via the profiles that they have been assigned.
If the string is contained in the mapping, the chkautattr call returns
an allowed response, if not, it returns a denied response to the system
call.
Example: Authorization check
ruid = getuid();
if ((pwp = getpwuid(ruid)) == NULL)
crabort(INVALIDUSER);
strcpy(real_login, pwp->pw_name);
if ((eflag || lflag || rflag) && argc == 1) {
if ((pwp = getpwnam(*argv)) == NULL)
crabort(INVALIDUSER);
if (!chkauthattr("auth_string", real_login)) {
if (pwp->pw_uid != ruid)
crabort(NOTROOT);
else
pp = getuser(ruid);
} else
pp = *argv++;
} else {
Authorizations
An authorization is a unique string that represents a user’s right to
perform some operation or class
of operations. Authorization definitions are stored in a database called
auth_attr(4). For
programming authorization checks, only the authorization name is
significant.
CreatingAuthorization Checks
To check authorizations, use the chkauthattr(3SECDB) library function,
which verifies whether
or not a user has a given authorization. The synopsis is:
int chkauthattr(const char *authname, const char *username);
The chkauthattr() function checks the policy.conf(4), user_attr(4), and
prof_attr(4)
databases in order for a match to the given authorization
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