Issued:
2017-03-02
Updated:
2017-03-02

RHSA-2017:0387 - Important: kernel-rt security and bug fix update

Synopsis

Important: kernel-rt security and bug fix update

Type/Severity

Security Advisory Important

Topic

An update for kernel-rt is now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements.

Security Fix(es):

  • Linux kernel built with the Kernel-based Virtual Machine (CONFIG_KVM) support is vulnerable to a null pointer dereference flaw. It could occur on x86 platform, when emulating an undefined instruction. An attacker could use this flaw to crash the host kernel resulting in DoS. (CVE-2016-8630, Important)

  • A race condition issue leading to a use-after-free flaw was found in the way the raw packet sockets implementation in the Linux kernel networking subsystem handled synchronization while creating the TPACKET_V3 ring buffer. A local user able to open a raw packet socket (requires the CAP_NET_RAW capability) could use this flaw to elevate their privileges on the system. (CVE-2016-8655, Important)

  • A flaw was discovered in the Linux kernel's implementation of VFIO. An attacker issuing an ioctl can create a situation where memory is corrupted and modify memory outside of the expected area. This may overwrite kernel memory and subvert kernel execution. (CVE-2016-9083, Important)

  • The use of a kzalloc with an integer multiplication allowed an integer overflow condition to be reached in vfio_pci_intrs.c. This combined with CVE-2016-9083 may allow an attacker to craft an attack and use unallocated memory, potentially crashing the machine. (CVE-2016-9084, Moderate)

Red Hat would like to thank Philip Pettersson for reporting CVE-2016-8655.

Bug Fix(es):

  • Previously, the asynchronous page fault woke code references spinlocks, which were actually sleeping locks in the RT kernel. Because of this, when the code was executed from the exception context, a bug warning appeared on the console. With this update, the regular wait queue and spinlock code in this area has been modified to use simple-wait-queue and raw-spinlocks. This code change enables the asynchronous page fault code to run in a non-preemptable state without bug warnings. (BZ#1418035)

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.

Affected Products

ProductVersionArch
Red Hat Enterprise Linux for Real Time7x86_64
Red Hat Enterprise Linux for Real Time for x86_64 - Extended Life Cycle Support7x86_64
Red Hat Enterprise Linux for Real Time for NFV7x86_64

Updated Packages

  • kernel-rt-trace-kvm-debuginfo-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm
  • kernel-rt-trace-kvm-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm
  • kernel-rt-debug-kvm-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm
  • kernel-rt-debuginfo-common-x86_64-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm
  • kernel-rt-debug-devel-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm
  • kernel-rt-debug-kvm-debuginfo-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm
  • kernel-rt-debug-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm
  • kernel-rt-debug-debuginfo-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm
  • kernel-rt-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm
  • kernel-rt-devel-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm
  • kernel-rt-doc-3.10.0-514.10.2.rt56.435.el7.noarch.rpm
  • kernel-rt-kvm-debuginfo-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm
  • kernel-rt-trace-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm
  • kernel-rt-3.10.0-514.10.2.rt56.435.el7.src.rpm
  • kernel-rt-debuginfo-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm
  • kernel-rt-trace-debuginfo-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm
  • kernel-rt-trace-devel-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm
  • kernel-rt-kvm-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm

Fixes

CVEs

References

Additional information