Debian Security Advisory

DLA-2323-1 linux-4.19 -- LTS new package

Date Reported:

12 Aug 2020

Affected Packages:

Vulnerable:

Yes

Security database references:

In the Debian bugtracking system: Bug 958300, Bug 960493, Bug 962254, Bug 963493, Bug 964153, Bug 964480, Bug 965365.
In Mitre's CVE dictionary: CVE-2019-18814, CVE-2019-18885, CVE-2019-20810, CVE-2020-10766, CVE-2020-10767, CVE-2020-10768, CVE-2020-12655, CVE-2020-12771, CVE-2020-13974, CVE-2020-15393.

More information:

Linux 4.19 has been packaged for Debian 9 as linux-4.19. This provides a supported upgrade path for systems that currently use kernel packages from the "stretch-backports" suite.

There is no need to upgrade systems using Linux 4.9, as that kernel version will also continue to be supported in the LTS period.

This backport does not include the following binary packages:

hyperv-daemons libbpf-dev libbpf4.19 libcpupower-dev libcpupower1 liblockdep-dev liblockdep4.19 linux-compiler-gcc-6-arm linux-compiler-gcc-6-x86 linux-cpupower linux-libc-dev lockdep usbip

Older versions of most of those are built from the linux source package in Debian 9.

The kernel images and modules will not be signed for use on systems with Secure Boot enabled, as there is no support for this in Debian 9.

Several vulnerabilities have been discovered in the Linux kernel that may lead to a denial of service or information leak.

CVE-2019-18814
Navid Emamdoost reported a potential use-after-free in the AppArmor security module, in the case that audit rule initialisation fails. The security impact of this is unclear.
CVE-2019-18885
The bobfuzzer team discovered that crafted Btrfs volumes could trigger a crash (oops). An attacker able to mount such a volume could use this to cause a denial of service.
CVE-2019-20810
A potential memory leak was discovered in the go7007 media driver. The security impact of this is unclear.
CVE-2020-10766
Anthony Steinhauser reported a flaw in the mitigation for Speculative Store Bypass (CVE-2018-3639) on x86 CPUs. A local user could use this to temporarily disable SSB mitigation in other users' tasks. If those other tasks run sandboxed code, this would allow that code to read sensitive information in the same process but outside the sandbox.
CVE-2020-10767
Anthony Steinhauser reported a flaw in the mitigation for Spectre variant 2 (CVE-2017-5715) on x86 CPUs. Depending on which other mitigations the CPU supports, the kernel might not use IBPB to mitigate Spectre variant 2 in user-space. A local user could use this to read sensitive information from other users' processes.
CVE-2020-10768
Anthony Steinhauser reported a flaw in the mitigation for Spectre variant 2 (CVE-2017-5715) on x86 CPUs. After a task force disabled indirect branch speculation through prctl(), it could still re-enable it later, so it was not possible to override a program that explicitly enabled it.
CVE-2020-12655
Zheng Bin reported that crafted XFS volumes could trigger a system hang. An attacker able to mount such a volume could use this to cause a denial of service.
CVE-2020-12771
Zhiqiang Liu reported a bug in the bcache block driver that could lead to a system hang. The security impact of this is unclear.
CVE-2020-13974
Kyungtae Kim reported a potential integer overflow in the vt (virtual terminal) driver. The security impact of this is unclear.
CVE-2020-15393
Kyungtae Kim reported a memory leak in the usbtest driver. The security impact of this is unclear.

For Debian 9 Stretch, these problems have been fixed in version 4.19.132-1~deb9u1. This update additionally fixes Debian bugs #958300, #960493, #962254, #963493, #964153, #964480, and #965365; and includes many more bug fixes from stable updates 4.19.119-4.19.132 inclusive.

We recommend that you upgrade your linux-4.19 packages.

For the detailed security status of linux-4.19 please refer to its security tracker page at: https://security-tracker.debian.org/tracker/linux-4.19

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS