On Tue, 2011-06-07 at 10:41 +0200, Jakub Hrozek wrote:
On 06/07/2011 04:59 AM, Stephen Gallagher wrote:
> While attempting to extract the SSSD's HBAC rule evaluation into a
> common library, I discovered several shortcomings. Some were related to
> extracting the library, others were related to the rule evaluation
> Related to extracting the library, I needed for the code to be able to
> identify and resolve without having direct access to LDAP or the LDB.
> This meant I could not rely on the memberOf objects to be valid.
> As for the rule evaluation, I discovered that we were only caching for
> offline use those remote hosts that had previously attempted to log in.
> This meant that if the IPA server was unreachable, valid users would be
> unable to log in from some valid machines.
> After careful consideration (and a few false starts), I decided that a
> total rewrite was necessary. So here it is.
> The major changes are these:
> 1) We have moved to always performing a full enumeration of known IPA
> hosts and HBAC services. This actually results in a net reduction in
> round-trips to the LDAP server, which was a primary bottleneck.
> Additionally, this means that we also have a full understanding when
> offline as to whether a remote host is permitted access or not.
> 2) I've added a configurable timeout for hbac rule refreshes to the LDAP
> server. Previously, if we were online, EVERY pam_account() request would
> result in at least one LDAP round-trip. By default, we'll only refresh
> the HBAC rules every five seconds now.
> 3) I broke the acquisition and processing of the rules, hosts and
> services into separate C files, as ipa_access.c was getting to be much
> to large to manage.
> The overall view of the code (when online) is this:
> A request comes in, we call to LDAP to get, in order, the set of known
> hosts, the set of known PAM services and then finally the set of
> *enabled* rules with the current ipa_hostname as the targethost.
> And now, the patches:
> Patch 0001: The new standalone evaluator library. It's very simple at
> the moment (but it will become much more complex in the near future when
> timerule evaluation is added). Jakub, Rob and I agreed on the interface
> and Jakub is creating Python bindings for it.
I'll rebase the bindings on top of these patches and send to the list.
> Patch 0002: This is the meat of the new IPA access backend. All of the
> helper functions necessary for looking up, storing and converting the
> hosts, rules and services are in this patch.
> Patch 0003: This is not really a patch as much as it is a trash can. I
> split this from Patch 0004 to make the latter more reviewable. Patch
> 0003 contains only the deletions of the old access provider
> Patch 0004: Adds the new IPA access provider, taking advantage of the
> helper functions from Patch 0002.
> Patch 0005: Adds a refresh timeout to reduce round-trips to IPA while
Nack, msgs2attrs_array() is not defined:
src/providers/ipa/ipa_access.c: In function 'hbac_get_cached_rules':
src/providers/ipa/ipa_access.c:589:5: error: implicit declaration of
function 'msgs2attrs_array' [-Werror=implicit-function-declaration]
cc1: some warnings being treated as errors
Whoops, I forgot I reordered some of my patches. I missed two at the
Patch 0001: Retrieve the group name as well as the GID during
sysdb_initgroups() (used later for getting the user memberships of a
user for evaluating the rules)
Patch 0002: Add a helper function to convert a list of ldb_messages to
The other patches are the same as the previous email, but numbered +2.