Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
libceph: Reject monmaps advertising zero monitors
A message of type CEPH_MSG_MON_MAP contains a monmap that is sent from a monitor to the client. This monmap contains information about the existing monitors in the cluster. Currently, a monmap indicating that there are zero monitors in the cluster is treated as valid. However, it is impossible to have zero monitors in the cluster and still receive a valid monmap from a monitor. Therefore, such a monmap must be corrupted and should be treated as invalid. Furthermore, a monmap with a monitor count of zero can subsequently crash the client when attempting to open a session with a monitor in __open_session(). This happens because the “BUG_ON(monc->monmap->num_mon < 1)” assertion in pick_new_mon() is triggered.
This patch extends a check in ceph_monmap_decode() to also reject arriving mon_maps with num_mon == 0 rather than only with num_mon > CEPH_MAX_MON.
[ idryomov: drop “log output for unusual values of num_mon” part ]
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , Debian 10 ELS , RHEL 7 ELS , TuxCare 9.6 ESU
- Affected packages:
- kernel @ 5.14.0 (+8 more)