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

• Red Hat Enterprise Linux for Real Time 7 x86_64
• Red Hat Enterprise Linux for Real Time for NFV 7 x86_64

Fixes

• BZ - 1389258 - CVE-2016-9083 kernel: State machine confusion bug in vfio driver leading to memory corruption
• BZ - 1389259 - CVE-2016-9084 kernel: Integer overflow when using kzalloc in vfio driver
• BZ - 1393350 - CVE-2016-8630 kernel: kvm: x86: NULL pointer dereference during instruction decode
• BZ - 1400019 - CVE-2016-8655 kernel: Race condition in packet_set_ring leads to use after free
• BZ - 1415172 - kernel-rt: update to the RHEL7.3.z batch#3 source tree [rt-7.3.z]

CVEs

• CVE-2016-8630
• CVE-2016-8655
• CVE-2016-9083
• CVE-2016-9084

References

• https://access.redhat.com/security/updates/classification/#important

Red Hat Enterprise Linux for Real Time 7

SRPM
kernel-rt-3.10.0-514.10.2.rt56.435.el7.src.rpm	SHA-256: 9b7aa0189e1f2f0d576d7d6f70b5b5aa0325b675e2aa0bb4990e97ee249a6040
x86_64
kernel-rt-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 00ce7965e3d87093700816c3f65bedb7d1e285517c6b72ff096f1d59a288eb05
kernel-rt-debug-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 83f5e85270dcf97733d1e3d0d764a7ccc5af3d747e5e75eea96e37a61e6e19d6
kernel-rt-debug-debuginfo-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 4c94bdd9791d943c77c01ebb2301f9614100416bebe5fbfcba648494d2130813
kernel-rt-debug-devel-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 1b5bd85c5cdd6421521b289dd27043636c8029adb65d68e7bbd59435607a7c17
kernel-rt-debuginfo-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 2ab1d2b40fa191c00b2f9ab74ce27a28698a552ffdcbb1f2af2b2c11d4ff6974
kernel-rt-debuginfo-common-x86_64-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 71a6abfb13c36a67d05076867efa1bf88bf0d6e9248e20aaa78565b68142e1ab
kernel-rt-devel-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 27fb1ade192b304b2e9a0e95ea73063980e23bd4d2485aa47df5d535c51dfb02
kernel-rt-doc-3.10.0-514.10.2.rt56.435.el7.noarch.rpm	SHA-256: ebe1c9131eead78e5007d0f607de16fb8f9ac865a972d8905c99e84b6a30547f
kernel-rt-trace-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: e69e30159ec790ffd9e56d2e0cc928433ddaeea4d6a8f7efa4d7b8b8d4d7df0d
kernel-rt-trace-debuginfo-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: cc53434a94593c987ac616f411df06640c35591abc2be828a8e3f9094d3127e5
kernel-rt-trace-devel-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: f3f9df598fc0f27cf0996ca65d9497e3a08a626949697a70d4edd45df269a9e6

Red Hat Enterprise Linux for Real Time for NFV 7

SRPM
kernel-rt-3.10.0-514.10.2.rt56.435.el7.src.rpm	SHA-256: 9b7aa0189e1f2f0d576d7d6f70b5b5aa0325b675e2aa0bb4990e97ee249a6040
x86_64
kernel-rt-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 00ce7965e3d87093700816c3f65bedb7d1e285517c6b72ff096f1d59a288eb05
kernel-rt-debug-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 83f5e85270dcf97733d1e3d0d764a7ccc5af3d747e5e75eea96e37a61e6e19d6
kernel-rt-debug-debuginfo-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 4c94bdd9791d943c77c01ebb2301f9614100416bebe5fbfcba648494d2130813
kernel-rt-debug-devel-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 1b5bd85c5cdd6421521b289dd27043636c8029adb65d68e7bbd59435607a7c17
kernel-rt-debug-kvm-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 62ff6c4b6a4baaa41b110e388ee7174034395049035b24b41e91592c786152d0
kernel-rt-debug-kvm-debuginfo-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: f64249876300ba4be6f64f35008ee5cbe2f72bc87c5aa6e445d38e16358c7900
kernel-rt-debuginfo-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 2ab1d2b40fa191c00b2f9ab74ce27a28698a552ffdcbb1f2af2b2c11d4ff6974
kernel-rt-debuginfo-common-x86_64-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 71a6abfb13c36a67d05076867efa1bf88bf0d6e9248e20aaa78565b68142e1ab
kernel-rt-devel-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 27fb1ade192b304b2e9a0e95ea73063980e23bd4d2485aa47df5d535c51dfb02
kernel-rt-doc-3.10.0-514.10.2.rt56.435.el7.noarch.rpm	SHA-256: ebe1c9131eead78e5007d0f607de16fb8f9ac865a972d8905c99e84b6a30547f
kernel-rt-kvm-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: abbb2945c933e2df10caa0e92d8e09f0b6184b62445a25311ec7908f71483c88
kernel-rt-kvm-debuginfo-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 893c4d699905e7bdd4a232c70ce1ad9076fc100191495f53d858b2cfffa8684e
kernel-rt-trace-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: e69e30159ec790ffd9e56d2e0cc928433ddaeea4d6a8f7efa4d7b8b8d4d7df0d
kernel-rt-trace-debuginfo-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: cc53434a94593c987ac616f411df06640c35591abc2be828a8e3f9094d3127e5
kernel-rt-trace-devel-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: f3f9df598fc0f27cf0996ca65d9497e3a08a626949697a70d4edd45df269a9e6
kernel-rt-trace-kvm-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: 3918c2515a8befebfc6c179330e29a253ea904deb1a3bf5da725977f319a0088
kernel-rt-trace-kvm-debuginfo-3.10.0-514.10.2.rt56.435.el7.x86_64.rpm	SHA-256: f3ca3b7d5a12ad7bce7337ea1da1aa52b458c4063bd39735120988fe0f82e7be