Debian Security Advisory
DLA-1989-1 linux -- LTS security update
- Date Reported:
- 12 Nov 2019
- Affected Packages:
- Security database references:
- In Mitre's CVE dictionary: CVE-2019-0154, CVE-2019-11135.
- More information:
Several vulnerabilities have been discovered in the Linux kernel that may lead to a privilege escalation, denial of service, or information leak.
Intel discovered that on their 8th and 9th generation GPUs, reading certain registers while the GPU is in a low-power state can cause a system hang. A local user permitted to use the GPU can use this for denial of service.
This update mitigates the issue through changes to the i915 driver.
The affected chips (gen8) are listed at en.wikipedia.org/wiki/List_of_Intel_graphics_processing_units.
It was discovered that on Intel CPUs supporting transactional memory (TSX), a transaction that is going to be aborted may continue to execute speculatively, reading sensitive data from internal buffers and leaking it through dependent operations. Intel calls this
TSX Asynchronous Abort(TAA).
For CPUs affected by the previously published Microarchitectural Data Sampling (MDS) issues (CVE-2018-12126, CVE-2018-12127, CVE-2018-12130, CVE-2019-11091), the existing mitigation also mitigates this issue.
For processors that are vulnerable to TAA but not MDS, this update disables TSX by default. This mitigation requires updated CPU microcode. An updated intel-microcode package (only available in Debian non-free) will be provided via a future DLA. The updated CPU microcode may also be available as part of a system firmware ("BIOS") update.
Further information on the mitigation can be found at www.kernel.org/…/tsx_async_abort.html or in the linux-doc-3.16 package.
Intel's explanation of the issue can be found at software.intel.com/…/deep-dive-intel-transactional-synchronization-extensions-intel-tsx-asynchronous-abort.
For Debian 8
Jessie, these problems have been fixed in version 3.16.76-1. This update also includes other fixes from upstream stable updates.
We recommend that you upgrade your linux packages.
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