Scientific Linux Security Update : kernel on SL6.x i386/x86_64

medium Nessus Plugin ID 61212

Synopsis

The remote Scientific Linux host is missing one or more security updates.

Description

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Security fix :

- Using the SG_IO IOCTL to issue SCSI requests to partitions or LVM volumes resulted in the requests being passed to the underlying block device. If a privileged user only had access to a single partition or LVM volume, they could use this flaw to bypass those restrictions and gain read and write access (and be able to issue other SCSI commands) to the entire block device.

In KVM (Kernel-based Virtual Machine) environments using raw format virtio disks backed by a partition or LVM volume, a privileged guest user could bypass intended restrictions and issue read and write requests (and other SCSI commands) on the host, and possibly access the data of other guests that reside on the same underlying block device. Partition-based and LVM-based storage pools are not used by default. (CVE-2011-4127, Important)

Bug fixes :

- Previously, idle load balancer kick requests from other CPUs could be serviced without first receiving an inter-processor interrupt (IPI). This could have led to a deadlock.

- This update fixes a performance regression that may have caused processes (including KVM guests) to hang for a number of seconds.

- When md_raid1_unplug_device() was called while holding a spinlock, under certain device failure conditions, it was possible for the lock to be requested again, deeper in the call chain, causing a deadlock. Now, md_raid1_unplug_device() is no longer called while holding a spinlock.

- In hpet_next_event(), an interrupt could have occurred between the read and write of the HPET (High Performance Event Timer) and the value of HPET_COUNTER was then beyond that being written to the comparator (HPET_Tn_CMP). Consequently, the timers were overdue for up to several minutes. Now, a comparison is performed between the value of the counter and the comparator in the HPET code. If the counter is beyond the comparator, the '-ETIME' error code is returned.

- Index allocation in the virtio-blk module was based on a monotonically increasing variable 'index'. Consequently, released indexes were not reused and after a period of time, no new were available. Now, virtio-blk uses the ida API to allocate indexes.

- A bug related to Context Caching existed in the Intel IOMMU support module. On some newer Intel systems, the Context Cache mode has changed from previous hardware versions, potentially exposing a Context coherency race.
The bug was exposed when performing a series of hot plug and unplug operations of a Virtual Function network device which was immediately configured into the network stack, i.e., successfully performed dynamic host configuration protocol (DHCP). When the coherency race occurred, the assigned device would not work properly in the guest virtual machine. With this update, the Context coherency is corrected and the race and potentially resulting device assignment failure no longer occurs.

- The align_va_addr kernel parameter was ignored if secondary CPUs were initialized. This happened because the parameter settings were overridden during the initialization of secondary CPUs. Also, the align_va_addr parameter documentation contained incorrect parameter arguments. With this update, the underlying code has been modified to prevent the overriding and the documentation has been updated.

- Dell systems based on a future Intel processor with graphics acceleration required the selection of the install system with basic video driver installation option. This update removes this requirement.

Solution

Update the affected packages.

See Also

http://www.nessus.org/u?fa4f0fa5

Plugin Details

Severity: Medium

ID: 61212

File Name: sl_20111222_kernel_on_SL6_x.nasl

Version: 1.6

Type: local

Agent: unix

Published: 8/1/2012

Updated: 1/14/2021

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Vector: CVSS2#AV:L/AC:L/Au:N/C:P/I:P/A:P

Vulnerability Information

CPE: x-cpe:/o:fermilab:scientific_linux

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/RedHat/release, Host/RedHat/rpm-list

Patch Publication Date: 12/22/2011

Vulnerability Publication Date: 7/3/2012

Reference Information

CVE: CVE-2011-4127