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 MRG 2.

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):

• A race condition flaw was found in the N_HLDC Linux kernel driver when accessing n_hdlc.tbuf list that can lead to double free. A local, unprivileged user able to set the HDLC line discipline on the tty device could use this flaw to increase their privileges on the system. (CVE-2017-2636, Important)
  
• A use-after-free flaw was found in the way the Linux kernel's Datagram Congestion Control Protocol (DCCP) implementation freed SKB (socket buffer) resources for a DCCP_PKT_REQUEST packet when the IPV6_RECVPKTINFO option is set on the socket. A local, unprivileged user could use this flaw to alter the kernel memory, allowing them to escalate their privileges on the system. (CVE-2017-6074, Important)
  
• A flaw was found in the Linux kernel key management subsystem in which a local attacker could crash the kernel or corrupt the stack and additional memory (denial of service) by supplying a specially crafted RSA key. This flaw panics the machine during the verification of the RSA key. (CVE-2016-8650, Moderate)
  
• A flaw was found in the Linux kernel's implementation of setsockopt for the SO_{SND|RCV}BUFFORCE setsockopt() system call. Users with non-namespace CAP_NET_ADMIN are able to trigger this call and create a situation in which the sockets sendbuff data size could be negative. This could adversely affect memory allocations and create situations where the system could crash or cause memory corruption. (CVE-2016-9793, Moderate)
  
• A flaw was found in the Linux kernel's handling of clearing SELinux attributes on /proc/pid/attr files. An empty (null) write to this file can crash the system by causing the system to attempt to access unmapped kernel memory. (CVE-2017-2618, Moderate)
  

Red Hat would like to thank Alexander Popov for reporting CVE-2017-2636; Andrey Konovalov (Google) for reporting CVE-2017-6074; and Ralf Spenneberg for reporting CVE-2016-8650. The CVE-2017-2618 issue was discovered by Paul Moore (Red Hat Engineering).

Bug Fix(es):

• The kernel-rt packages have been upgraded to version 3.10.0-514.rt56.219, which provides a number of bug fix updates over the previous version. (BZ#1429613)

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

• MRG Realtime 2 x86_64

Fixes

• BZ - 1395187 - CVE-2016-8650 kernel: Null pointer dereference via keyctl
• BZ - 1402013 - CVE-2016-9793 kernel: Signed overflow for SO_{SND|RCV}BUFFORCE
• BZ - 1419916 - CVE-2017-2618 kernel: Off-by-one error in selinux_setprocattr (/proc/self/attr/fscreate)
• BZ - 1423071 - CVE-2017-6074 kernel: use after free in dccp protocol
• BZ - 1428319 - CVE-2017-2636 kernel: Race condition access to n_hdlc.tbuf causes double free in n_hdlc_release()
• BZ - 1429613 - update the MRG 2.5.z 3.10 kernel-rt sources

CVEs

• CVE-2016-8650
• CVE-2016-9793
• CVE-2017-2618
• CVE-2017-2636
• CVE-2017-6074

References

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

MRG Realtime 2

SRPM
kernel-rt-3.10.0-514.rt56.219.el6rt.src.rpm	SHA-256: c95df7676e85f35fae36e3015f35791de885c6d5e1d7fd20d9e06baf414f2fdf
x86_64
kernel-rt-3.10.0-514.rt56.219.el6rt.x86_64.rpm	SHA-256: 916c0c7c4b9a2c9a15794663f5f4d3edc5f631f6c367af13bd384b9faadbeead
kernel-rt-debug-3.10.0-514.rt56.219.el6rt.x86_64.rpm	SHA-256: 14ca5854add626601d1d307fd0c008527d14907c6ec0408f22e9843fc7f732f6
kernel-rt-debug-debuginfo-3.10.0-514.rt56.219.el6rt.x86_64.rpm	SHA-256: ffaf9639c31c05c34595d9500150f6cb4739207b07f666aa7c6afe1a239871f2
kernel-rt-debug-devel-3.10.0-514.rt56.219.el6rt.x86_64.rpm	SHA-256: 852f4e88b909ea7bfe589ea38b8d3fe3c61bc196101ef20415d2f024f7419ab7
kernel-rt-debuginfo-3.10.0-514.rt56.219.el6rt.x86_64.rpm	SHA-256: 77903ffd4fe1e79cde1a4443a32fd4f6217be62ce9eff22dc1c43c122acc0696
kernel-rt-debuginfo-common-x86_64-3.10.0-514.rt56.219.el6rt.x86_64.rpm	SHA-256: 573550a0a7e493c9e83fe8efd26c7d69147c5fbdaf469b41781f0013a3247fd6
kernel-rt-devel-3.10.0-514.rt56.219.el6rt.x86_64.rpm	SHA-256: 716425ea1d23ecc0bc3d96831f8203b5a62459ae672e378f35ed51f46b24d9c2
kernel-rt-doc-3.10.0-514.rt56.219.el6rt.noarch.rpm	SHA-256: 517c293af0fe53ef5d3053b4d2041954e1188e224ad0ae29af1a073d0abd897f
kernel-rt-firmware-3.10.0-514.rt56.219.el6rt.noarch.rpm	SHA-256: e4082d03e4e4cdd69ec63e9e0427187aec34bffdefb0162af3401a2dcd845a86
kernel-rt-trace-3.10.0-514.rt56.219.el6rt.x86_64.rpm	SHA-256: 735d883052ed03dcf4e74da0f440aa185ca35fc64d9fde6eab5f7ba453cf4c77
kernel-rt-trace-debuginfo-3.10.0-514.rt56.219.el6rt.x86_64.rpm	SHA-256: fb5766257319f9ae2c22e6b2a526a714bcfdf319095e0d5344a43fcfedef8306
kernel-rt-trace-devel-3.10.0-514.rt56.219.el6rt.x86_64.rpm	SHA-256: aad0964e63328813f775791495d573a45cdcf41a94583a70e5267b9781229f65
kernel-rt-vanilla-3.10.0-514.rt56.219.el6rt.x86_64.rpm	SHA-256: 5ee65a9b960171b4944b130e401a563217e8f364ea316ff600a0bf63224a040c
kernel-rt-vanilla-debuginfo-3.10.0-514.rt56.219.el6rt.x86_64.rpm	SHA-256: 8e34df15a7865b9e4558ecd4e467578ed778ade6da348da6408b24f4881d8c91
kernel-rt-vanilla-devel-3.10.0-514.rt56.219.el6rt.x86_64.rpm	SHA-256: 3825d49a021e12d80e32277bd7faed73bc6f1e78a8d8d120599e5216a4284987