==========================================================================
Ubuntu Security Notice USN-3980-2
May 14, 2019

linux-hwe, linux-azure vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 18.04 LTS

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux-azure: Linux kernel for Microsoft Azure Cloud systems
- linux-hwe: Linux hardware enablement (HWE) kernel

Details:

USN-3980-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.10.
This update provides the corresponding updates for the Linux
Hardware Enablement (HWE) kernel from Ubuntu 18.10 for Ubuntu
18.04 LTS.

Ke Sun, Henrique Kawakami, Kekai Hu, Rodrigo Branco, Giorgi Maisuradze, Dan
Horea Lutas, Andrei Lutas, Volodymyr Pikhur, Stephan van Schaik, Alyssa
Milburn, Sebastian Österlund, Pietro Frigo, Kaveh Razavi, Herbert Bos,
Cristiano Giuffrida, Moritz Lipp, Michael Schwarz, and Daniel Gruss
discovered that memory previously stored in microarchitectural fill buffers
of an Intel CPU core may be exposed to a malicious process that is
executing on the same CPU core. A local attacker could use this to expose
sensitive information. (CVE-2018-12130)

Brandon Falk, Ke Sun, Henrique Kawakami, Kekai Hu, Rodrigo Branco, Stephan
van Schaik, Alyssa Milburn, Sebastian Österlund, Pietro Frigo, Kaveh
Razavi, Herbert Bos, and Cristiano Giuffrida discovered that memory
previously stored in microarchitectural load ports of an Intel CPU core may
be exposed to a malicious process that is executing on the same CPU core. A
local attacker could use this to expose sensitive information.
(CVE-2018-12127)

Ke Sun, Henrique Kawakami, Kekai Hu, Rodrigo Branco, Marina Minkin, Daniel
Moghimi, Moritz Lipp, Michael Schwarz, Jo Van Bulck, Daniel Genkin, Daniel
Gruss, Berk Sunar, Frank Piessens, and Yuval Yarom discovered that memory
previously stored in microarchitectural store buffers of an Intel CPU core
may be exposed to a malicious process that is executing on the same CPU
core. A local attacker could use this to expose sensitive information.
(CVE-2018-12126)

Vasily Averin and Evgenii Shatokhin discovered that a use-after-free
vulnerability existed in the NFS41+ subsystem when multiple network
namespaces are in use. A local attacker in a container could use this to
cause a denial of service (system crash) or possibly execute arbitrary
code. (CVE-2018-16884)

Ke Sun, Henrique Kawakami, Kekai Hu, Rodrigo Branco, Volodrmyr Pikhur,
Moritz Lipp, Michael Schwarz, Daniel Gruss, Stephan van Schaik, Alyssa
Milburn, Sebastian Österlund, Pietro Frigo, Kaveh Razavi, Herbert Bos, and
Cristiano Giuffrida discovered that uncacheable memory previously stored in
microarchitectural buffers of an Intel CPU core may be exposed to a
malicious process that is executing on the same CPU core. A local attacker
could use this to expose sensitive information. (CVE-2019-11091)

Matteo Croce, Natale Vinto, and Andrea Spagnolo discovered that the cgroups
subsystem of the Linux kernel did not properly account for SCTP socket
buffers. A local attacker could use this to cause a denial of service
(system crash). (CVE-2019-3874)

Alex Williamson discovered that the vfio subsystem of the Linux kernel did
not properly limit DMA mappings. A local attacker could use this to cause a
denial of service (memory exhaustion). (CVE-2019-3882)

Marc Orr discovered that the KVM hypervisor implementation in the Linux
kernel did not properly restrict APIC MSR register values when nested
virtualization is used. An attacker in a guest vm could use this to cause a
denial of service (host OS crash). (CVE-2019-3887)

Hugues Anguelkov discovered that the Broadcom Wifi driver in the Linux
kernel contained a heap buffer overflow. A physically proximate attacker
could use this to cause a denial of service (system crash) or possibly
execute arbitrary code. (CVE-2019-9500)

Hugues Anguelkov discovered that the Broadcom Wifi driver in the Linux
kernel did not properly prevent remote firmware events from being processed
for USB Wifi devices. A physically proximate attacker could use this to
send firmware events to the device. (CVE-2019-9503)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 18.04 LTS:
  linux-image-4.18.0-1018-azure   4.18.0-1018.18~18.04.1
  linux-image-4.18.0-20-generic   4.18.0-20.21~18.04.1
  linux-image-4.18.0-20-generic-lpae  4.18.0-20.21~18.04.1
  linux-image-4.18.0-20-lowlatency  4.18.0-20.21~18.04.1
  linux-image-4.18.0-20-snapdragon  4.18.0-20.21~18.04.1
  linux-image-azure               4.18.0.1018.17
  linux-image-generic-hwe-18.04   4.18.0.20.70
  linux-image-generic-lpae-hwe-18.04  4.18.0.20.70
  linux-image-lowlatency-hwe-18.04  4.18.0.20.70
  linux-image-snapdragon-hwe-18.04  4.18.0.20.70
  linux-image-virtual-hwe-18.04   4.18.0.20.70

After a standard system update you need to reboot your computer to make
all the necessary changes.

Please note that fully mitigating the Microarchitectural Data Sampling
(MDS) issues (CVE-2018-12126, CVE-2018-12127, CVE-2018-12130, and
CVE-2019-11091) requires corresponding processor microcode/firmware
updates or, in virtual environments, hypervisor updates.

References:
  https://usn.ubuntu.com/usn/usn-3980-2
  https://usn.ubuntu.com/usn/usn-3980-1
  CVE-2018-12126, CVE-2018-12127, CVE-2018-12130,
  CVE-2018-16884, CVE-2019-11091, CVE-2019-3874,
  CVE-2019-3882, CVE-2019-3887, CVE-2019-9500, CVE-2019-9503,
  https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/MDS

Package Information:
  https://launchpad.net/ubuntu/+source/linux-azure/4.18.0-1018.18~18.04.1
  https://launchpad.net/ubuntu/+source/linux-hwe/4.18.0-20.21~18.04.1