7.2 - RHSA-2016:0855

Problem Description:

An update for kernel is now available for Red Hat Enterprise Linux 6.

Red Hat Product Security has rated this update as having a security impact of Moderate. 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.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Desktop (v. 6) - i386, noarch, x86_64 Red Hat Enterprise Linux Desktop Optional (v. 6) - i386, x86_64 Red Hat Enterprise Linux HPC Node (v. 6) - noarch, x86_64 Red Hat Enterprise Linux HPC Node Optional (v. 6) - x86_64 Red Hat Enterprise Linux Server (v. 6) - i386, noarch, ppc64, s390x, x86_64 Red Hat Enterprise Linux Server Optional (v. 6) - i386, ppc64, s390x, x86_64 Red Hat Enterprise Linux Workstation (v. 6) - i386, noarch, x86_64 Red Hat Enterprise Linux Workstation Optional (v. 6) - i386, x86_64

3. Description:

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

Security Fix(es):

* It was found that reporting emulation failures to user space could lead to either a local (CVE-2014-7842) or a L2->L1 (CVE-2010-5313) denial of service. In the case of a local denial of service, an attacker must have access to the MMIO area or be able to access an I/O port. Please note that on certain systems, HPET is mapped to userspace as part of vdso (vvar) and thus an unprivileged user may generate MMIO transactions (and enter the emulator) this way. (CVE-2010-5313, CVE-2014-7842, Moderate)

* It was found that the Linux kernel did not properly account file descriptors passed over the unix socket against the process limit. A local user could use this flaw to exhaust all available memory on the system. (CVE-2013-4312, Moderate)

* A buffer overflow flaw was found in the way the Linux kernel's virtio-net subsystem handled certain fraglists when the GRO (Generic Receive Offload) functionality was enabled in a bridged network configuration. An attacker on the local network could potentially use this flaw to crash the system, or, although unlikely, elevate their privileges on the system. (CVE-2015-5156, Moderate)

* It was found that the Linux kernel's IPv6 network stack did not properly validate the value of the MTU variable when it was set. A remote attacker could potentially use this flaw to disrupt a target system's networking (packet loss) by setting an invalid MTU value, for example, via a NetworkManager daemon that is processing router advertisement packets running on the target system. (CVE-2015-8215, Moderate)

* A NULL pointer dereference flaw was found in the way the Linux kernel's network subsystem handled socket creation with an invalid protocol identifier. A local user could use this flaw to crash the system. (CVE-2015-8543, Moderate)

* It was found that the espfix functionality does not work for 32-bit KVM paravirtualized guests. A local, unprivileged guest user could potentially use this flaw to leak kernel stack addresses. (CVE-2014-8134, Low)

* A flaw was found in the way the Linux kernel's ext4 file system driver handled non-journal file systems with an orphan list. An attacker with physical access to the system could use this flaw to crash the system or, although unlikely, escalate their privileges on the system. (CVE-2015-7509, Low)

* A NULL pointer dereference flaw was found in the way the Linux kernel's ext4 file system driver handled certain corrupted file system images. An attacker with physical access to the system could use this flaw to crash the system. (CVE-2015-8324, Low)

Red Hat would like to thank Nadav Amit for reporting CVE-2010-5313 and CVE-2014-7842, Andy Lutomirski for reporting CVE-2014-8134, and Dmitriy Monakhov (OpenVZ) for reporting CVE-2015-8324. The CVE-2015-5156 issue was discovered by Jason Wang (Red Hat).

Additional Changes:

* Refer to Red Hat Enterprise Linux 6.8 Release Notes for information on new kernel features and known issues, and Red Hat Enterprise Linux Technical Notes for information on device driver updates, important changes to external kernel parameters, notable bug fixes, and technology previews. Both of these documents are linked to in the References section.

4. 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.

5. Bugs fixed (https://bugzilla.redhat.com/):

697750 - [xfs] concurrent aio/dio got stuck 723722 - BUG: SELinux is preventing /usr/bin/nautilus (deleted) "write" access on /media/TerraVolume. 889368 - LVM RAID: I/O can hang if entire stripe (mirror group) of RAID10 LV is killed while under snapshot 1066751 - tmpfs: creates files with inode number 0, rendering parent directory unremovable 1163762 - CVE-2010-5313 CVE-2014-7842 kernel: kvm: reporting emulation failures to userspace 1172765 - CVE-2014-8134 kernel: x86: espfix not working for 32-bit KVM paravirt guests 1197875 - CIFS DFS shares fail to mount when specifying sec= option 1225359 - bonding: fail to configure master mac address by initscripts 1242239 - md raid1 writemostly feature broken 1243852 - CVE-2015-5156 kernel: buffer overflow with fraglist larger than MAX_SKB_FRAGS + 2 in virtio-net 1248507 - kernel: [drm:cpt_set_fifo_underrun_reporting] *ERROR* uncleared pch fifo underrun on pch transcoder A 1254020 - RHEL6.6: NFS client has kernel panic after seeing 'VFS: Busy inodes after unmount ... Self-destruct in 5 seconds. Have a nice day' 1259222 - CVE-2015-7509 kernel: Mounting ext2 fs e2fsprogs/tests/f_orphan as ext4 crashes system 1259870 - Incomplete nl80211 backport broke hostapd 1267261 - CVE-2015-8324 kernel: Null pointer dereference when mounting ext4 1283253 - CVE-2015-8215 kernel: MTU value is not validated in IPv6 stack causing packet loss 1290475 - CVE-2015-8543 kernel: IPv6 connect causes DoS via NULL pointer dereference 1297813 - CVE-2013-4312 kernel: File descriptors passed over unix sockets are not properly accounted 1310661 - BUG: unable to handle kernel paging request at 65642072 followed by kernel panic