We will be scheduling an important kernel security update this weekend.
This would take place as far as possible during the off-peak hours. A reboot is required to complete the upgrade. The downtime should not exceed 30 minutes and it will be minimize as much as possible. We will track each server till it returns to service after the upgrade and reboot.
This upgrade is scheduled as follows:
Date: 23 June 2012 (Saturday) to 25 June 2012 (Monday)
Time: Between 2AM and 8AM EST#
Kernel security update
Details of Kernel security update
* It was found that the Xen hypervisor implementation as shipped with Red Hat Enterprise Linux 5 did not properly restrict the sys call return addresses in the sysret return path to canonical addresses. An unprivileged user in a 64-bit para-virtualized guest, that is running on a 64-bit host that has an Intel CPU, could use this flaw to crash the host or, potentially, escalate their privileges, allowing them to execute arbitrary code at the hypervisor level. (CVE-2012-0217, Important)
* It was found that guests could trigger a bug in earlier AMD CPUs, leading to a CPU hard lockup, when running on the Xen hypervisor implementation. An unprivileged user in a 64-bit para-virtualized guest could use this flaw to crash the host. Warning: After installing this update, hosts that are using an affected AMD CPU (refer to Red Hat Bugzilla bug #824966 for a list) will fail to boot. In order to boot such hosts, the new kernel parameter, allow_unsafe, can be used ("allow_unsafe=on"). This option should only be used with hosts that are running trusted guests, as setting it to "on" reintroduces the flaw (allowing guests to crash the host). (CVE-2012-2934, Moderate)
Çərşənbə, İyun 20, 2012
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