On 05/29/2014 01:31 PM, Simo Sorce wrote:
On Thu, 2014-05-29 at 18:50 +0200, Petr Spacek wrote:
On 29.5.2014 13:48, Sumit Bose wrote:
== slapi-nis plugin/compat tree ==
The compat tree offers a simplified LDAP tree with user and group data
for legacy clients. No data for this tree is stored on disk but it is
always created on the fly. It has to be noted that legacy clients might
be one of the major users of the user-views because chances are that
they were attached to the legacy systems with legacy ID management which
should be replaced by IPA.

In contrast to the extdom plugin it is not possible to determine the
client based on the DN because connection might be anonymous. The
Slapi_PBlock contains the IP address of the client in
SLAPI_CONN_CLIENTNETADDR. Finding the matching client object in the IPA
tree requires a reverse-DNS lookup which might be unreliable. If the
reverse-DNS lookup was successful the slapi-nos plugin can follow the
same steps as the extdom plugin to lookup up and apply the view.
Do we really want to base security decisions on reverse DNS resolution?
No we do not want to play these games.

That
will be insecure. Attacker could tamper with reverse DNS to change UID/GID
mapping ... Maybe we can store IP->view mapping in the LDAP database. That
should be reliable if we assume that only TCP is used for connection to LDAP
database.
It is not just about it being insecure, it is about it being wrong.
As soon as you have a bunch of clients behind a NAT this pans goes belly
up.

As a alternative slapi-nis can provide one tree for each view.
This is the only alternative, if we decide to pursue it.

Simo.

Can we at least do something like CoS and use the base compat tree and overwrite just uid/gid on the fly instead of using the whole another view? That would reduce the size of the additional views significantly and would save cycles used for keeping each view in sync with underlying DB. In this case there will be still one view and dynamic overwrite in the search results.

--
Thank you,
Dmitri Pal

Sr. Engineering Manager IdM portfolio
Red Hat, Inc.

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