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Ubuntu Security Notice USN-4369-2
May 28, 2020

linux, linux-raspi2, linux-raspi2-5.3 regression
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 19.10
- Ubuntu 18.04 LTS

Summary:

USN-4369-1 introduced a regression in the Linux kernel.

Software Description:
- linux: Linux kernel
- linux-raspi2: Linux kernel for Raspberry Pi (V7) systems
- linux-raspi2-5.3: Linux kernel for Raspberry Pi (V7) systems

Details:

USN-4369-1 fixed vulnerabilities in the 5.3 Linux kernel. Unfortunately,
that update introduced a regression in overlayfs. This update corrects
the problem.

We apologize for the inconvenience.

Original advisory details:

 It was discovered that the btrfs implementation in the Linux kernel did not
 properly detect that a block was marked dirty in some situations. An
 attacker could use this to specially craft a file system image that, when
 unmounted, could cause a denial of service (system crash). (CVE-2019-19377)

 Tristan Madani discovered that the file locking implementation in the Linux
 kernel contained a race condition. A local attacker could possibly use this
 to cause a denial of service or expose sensitive information.
 (CVE-2019-19769)

 It was discovered that the Serial CAN interface driver in the Linux kernel
 did not properly initialize data. A local attacker could use this to expose
 sensitive information (kernel memory). (CVE-2020-11494)

 It was discovered that the linux kernel did not properly validate certain
 mount options to the tmpfs virtual memory file system. A local attacker
 with the ability to specify mount options could use this to cause a denial
 of service (system crash). (CVE-2020-11565)

 It was discovered that the OV51x USB Camera device driver in the Linux
 kernel did not properly validate device metadata. A physically proximate
 attacker could use this to cause a denial of service (system crash).
 (CVE-2020-11608)

 It was discovered that the STV06XX USB Camera device driver in the Linux
 kernel did not properly validate device metadata. A physically proximate
 attacker could use this to cause a denial of service (system crash).
 (CVE-2020-11609)

 It was discovered that the Xirlink C-It USB Camera device driver in the
 Linux kernel did not properly validate device metadata. A physically
 proximate attacker could use this to cause a denial of service (system
 crash). (CVE-2020-11668)

 It was discovered that the block layer in the Linux kernel contained a race
 condition leading to a use-after-free vulnerability. A local attacker could
 possibly use this to cause a denial of service (system crash) or execute
 arbitrary code. (CVE-2020-12657)

Update instructions:

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

Ubuntu 19.10:
  linux-image-5.3.0-1026-raspi2   5.3.0-1026.28
  linux-image-5.3.0-55-generic    5.3.0-55.49
  linux-image-5.3.0-55-generic-lpae  5.3.0-55.49
  linux-image-5.3.0-55-lowlatency  5.3.0-55.49
  linux-image-5.3.0-55-snapdragon  5.3.0-55.49
  linux-image-generic             5.3.0.55.47
  linux-image-generic-lpae        5.3.0.55.47
  linux-image-lowlatency          5.3.0.55.47
  linux-image-raspi2              5.3.0.1026.23
  linux-image-snapdragon          5.3.0.55.47
  linux-image-virtual             5.3.0.55.47

Ubuntu 18.04 LTS:
  linux-image-5.3.0-1026-raspi2   5.3.0-1026.28~18.04.1
  linux-image-raspi2-hwe-18.04    5.3.0.1026.15

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

ATTENTION: Due to an unavoidable ABI change the kernel updates have
been given a new version number, which requires you to recompile and
reinstall all third party kernel modules you might have installed.
Unless you manually uninstalled the standard kernel metapackages
(e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual,
linux-powerpc), a standard system upgrade will automatically perform
this as well.

References:
  https://usn.ubuntu.com/4369-2
  https://usn.ubuntu.com/4369-1
  https://launchpad.net/bugs/1879690

Package Information:
  https://launchpad.net/ubuntu/+source/linux/5.3.0-55.49
  https://launchpad.net/ubuntu/+source/linux-raspi2/5.3.0-1026.28
  https://launchpad.net/ubuntu/+source/linux-raspi2-5.3/5.3.0-1026.28~18.04.1