USN-4184-2

USN-4184-1 fixed vulnerabilities in the Linux kernel. It was discovered that the kernel fix for CVE-2019-0155 (i915 missing Blitter Command Streamer check) was incomplete on 64-bit Intel x86 systems. Also, the update introduced a regression that broke KVM guests where extended page tables (EPT) are disabled or not supported. This update addresses both issues.

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Original advisory details:

Stephan van Schaik, Alyssa Milburn, Sebastian Österlund, Pietro Frigo, Kaveh Razavi, Herbert Bos, Cristiano Giuffrida, Giorgi Maisuradze, Moritz Lipp, Michael Schwarz, Daniel Gruss, and Jo Van Bulck discovered that Intel processors using Transactional Synchronization Extensions (TSX) could expose memory contents previously stored in microarchitectural buffers to a malicious process that is executing on the same CPU core. A local attacker could use this to expose sensitive information. (CVE-2019-11135)

It was discovered that the Intel i915 graphics chipsets allowed userspace to modify page table entries via writes to MMIO from the Blitter Command Streamer and expose kernel memory information. A local attacker could use this to expose sensitive information or possibly elevate privileges. (CVE-2019-0155)

Deepak Gupta discovered that on certain Intel processors, the Linux kernel did not properly perform invalidation on page table updates by virtual guest operating systems. A local attacker in a guest VM could use this to cause a denial of service (host system crash). (CVE-2018-12207)

It was discovered that the Intel i915 graphics chipsets could cause a system hang when userspace performed a read from GT memory mapped input output (MMIO) when the product is in certain low power states. A local attacker could use this to cause a denial of service. (CVE-2019-0154)

Hui Peng discovered that the Atheros AR6004 USB Wi-Fi device driver for the Linux kernel did not properly validate endpoint descriptors returned by the device. A...