Open Stack

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Some versions of Glance do not apply property protections as expected
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### Summary ###
Tom Leaman reported an issue to the OpenStack mailing list that affects
Glance property protections. A permissive property setting in the Glance
property protections configuration file will override any previously set
stricter ones.

### Affected Services / Software ###
Glance, Folsom, Grizzly

### Discussion ###
Glance property protections limit the users who can perform CRUD
operations on a Glance property to those in specific roles. If there is
a specific rule that would reject an action and a less specific rule
that comes after that accepts the action, then the action is accepted
even though one may expect it to be rejected.

This bug only affects the use of user-roles in Glance. It does not occur
when policies are used to determine property protections.

In the following policy-protections.conf example, the desired result is
to restrict 'update' and 'delete' permissions for 'foo_property' to only
users with the 'admin' role.

- --- Begin Example ---
/etc/glance/property-protections.conf
[^foo_property$]
create = @
read = @
update = admin
delete = admin

[.*]
create = @
read = @
update = @
delete = @
- --- End Example ---

Due to the order that the rules are applied in the Folsom and Grizzly
OpenStack releases, the admin restriction for 'foo_property' is
nullified by the '.*' permissions. This results in all roles being
allowed the 'update' and 'delete' permissions on 'foo_property', which
is not what was intended.

### Recommended Actions ###
This issue has been fixed in Havana (Glance 2013.2.2) and subsequent
releases.

Users of affected releases should review and reorder the entries in
property-protections.conf to place the most open permissions at the
start of the configuration and more restrictive ones at the end, as
demonstrated below.

- --- Begin Example ---
/etc/Glance/property-protections.conf
[.*]
create = @
read = @
update = @
delete = @

[^foo_property$]
create = @
read = @
update = admin
delete = admin
- --- End Example ---

In the above example, '.*' and 'foo_property' entries in the protections
file have been reversed, ensuring that the more restrictive permissions
required for 'foo_property' are applied after the wider '.*' permissions
and assuring that 'update' and 'delete' operations are restricted to
only users with in the 'admin' role.

Configuration files with multiple property protection entries set should
be tested to ensure that CRUD actions are constrained in the way the
administrator intended.

### Contacts / References ###
This OSSN : https://wiki.openstack.org/wiki/OSSN/OSSN-0013
Original Launchpad Bug : https://bugs.launchpad.net/glance/+bug/1271426
Original Report :
http://lists.openstack.org/pipermail/openstack-dev/2014-January/024861.html
Glance Property Protections :
https://wiki.openstack.org/wiki/Glance-property-protections
OpenStack Security ML : openstack-security at lists.openstack.org
OpenStack Security Group : https://launchpad.net/~openstack-ossg
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