CVE request: pacemaker DoS when pacemaker remote is in use

[Cedric Buissart <cbuissar () redhat com>]

Hi all,

Last February was reported a vulnerability against pacemaker when pacemaker
remote is in use, allowing a remote, unauthenticated, attacker to launch a
DoS attack.
I have not found a CVE request for it, so here is one :

If a corosync node is connected to a pacemaker_remote node, the
connection can be trivially killed simply by connecting to the remote on its
standard TCP port (typically 3121):

2016-02-18T18:06:45.258661+00:00 d52-54-77-77-77-01 crmd[2637]:    error:
Unexpected pacemaker_remote client takeover. Disconnecting

Takeover is allowed in order to support migration of the remote primitive
from
one corosync node to another, but since this is a trivial denial of service
attack, it should only be allowed once a valid authkey is provided.

The flaw has been fixed in Pacemaker-1.1.15

=> Upstream bug :
 - Bug 5269 - DoS: valid authkey should be required for takeover of a
Pacemaker remote
http://bugs.clusterlabs.org/show_bug.cgi?id=5269

=> Upstream fix :
 - Fix: remote: cl#5269 - Notify other clients of a new connection only if
the handshake has completed (bsc#967388)
https://github.com/ClusterLabs/pacemaker/commit/5ec24a26

Thanks!

-- 
Cedric Buissart,
Product Security