linux security update

Package        : linux
CVE ID         : CVE-2016-9588 CVE-2017-2636 CVE-2017-5669 CVE-2017-5986 
                 CVE-2017-6214 CVE-2017-6345 CVE-2017-6346 CVE-2017-6348 
                 CVE-2017-6353

Several vulnerabilities have been discovered in the Linux kernel that
may lead to a privilege escalation, denial of service or have other
impacts.

CVE-2016-9588

    Jim Mattson discovered that the KVM implementation for Intel x86
    processors does not properly handle #BP and #OF exceptions in an
    L2 (nested) virtual machine. A local attacker in an L2 guest VM
    can take advantage of this flaw to cause a denial of service for
    the L1 guest VM.

CVE-2017-2636

    Alexander Popov discovered a race condition flaw in the n_hdlc
    line discipline that can lead to a double free. A local
    unprivileged user can take advantage of this flaw for privilege
    escalation. On systems that do not already have the n_hdlc module
    loaded, this can be mitigated by disabling it:
    echo >> /etc/modprobe.d/disable-n_hdlc.conf install n_hdlc false

CVE-2017-5669

    Gareth Evans reported that privileged users can map memory at
    address 0 through the shmat() system call. This could make it
    easier to exploit other kernel security vulnerabilities via a
    set-UID program.

CVE-2017-5986

    Alexander Popov reported a race condition in the SCTP
    implementation that can be used by local users to cause a
    denial-of-service (crash). The initial fix for this was incorrect
    and introduced further security issues (CVE-2017-6353). This
    update includes a later fix that avoids those. On systems that do
    not already have the sctp module loaded, this can be mitigated by
    disabling it:
    echo >> /etc/modprobe.d/disable-sctp.conf install sctp false

CVE-2017-6214

    Dmitry Vyukov reported a bug in the TCP implementation's handling
    of urgent data in the splice() system call. This can be used by a
    remote attacker for denial-of-service (hang) against applications
    that read from TCP sockets with splice().

CVE-2017-6345

    Andrey Konovalov reported that the LLC type 2 implementation
    incorrectly assigns socket buffer ownership. This can be used
    by a local user to cause a denial-of-service (crash). On systems
    that do not already have the llc2 module loaded, this can be
    mitigated by disabling it:
    echo >> /etc/modprobe.d/disable-llc2.conf install llc2 false

CVE-2017-6346

    Dmitry Vyukov reported a race condition in the raw packet (af_packet)
    fanout feature. Local users with the CAP_NET_RAW capability (in any
    user namespace) can use this for denial-of-service and possibly for
    privilege escalation.

CVE-2017-6348

    Dmitry Vyukov reported that the general queue implementation in
    the IrDA subsystem does not properly manage multiple locks,
    possibly allowing local users to cause a denial-of-service
    (deadlock) via crafted operations on IrDA devices.

For the stable distribution (jessie), these problems have been fixed in
version 3.16.39-1+deb8u2.

We recommend that you upgrade your linux packages.