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CVE-2020-27777

Published: 15 December 2020

A flaw was found in the way RTAS handled memory accesses in userspace to kernel communication. On a locked down (usually due to Secure Boot) guest system running on top of PowerVM or KVM hypervisors (pseries platform) a root like local user could use this flaw to further increase their privileges to that of a running kernel.

From the Ubuntu Security Team

Daniel Axtens discovered that PowerPC RTAS implementation in the Linux kernel did not properly restrict memory accesses in some situations. A privileged local attacker could use this to arbitrarily modify kernel memory, potentially bypassing kernel lockdown restrictions.

Notes

AuthorNote
sbeattie
fix needs typo correction from lkml link in refs

Priority

Medium

Cvss 3 Severity Score

6.7

Score breakdown

Status

Package Release Status
linux-aws-5.0
Launchpad, Ubuntu, Debian
focal Does not exist

bionic Not vulnerable
(powerpc only)
groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-azure-edge
Launchpad, Ubuntu, Debian
focal Does not exist

bionic Not vulnerable
(powerpc only)
groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-snapdragon
Launchpad, Ubuntu, Debian
focal Does not exist

bionic Not vulnerable
(powerpc only)
groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Not vulnerable
(powerpc only)
linux-gke-5.0
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-hwe
Launchpad, Ubuntu, Debian
xenial
Released (4.15.0-129.132~16.04.1)
bionic Ignored
(replaced by linux-hwe-5.4)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
linux-gke-5.4
Launchpad, Ubuntu, Debian
focal Does not exist

groovy Does not exist

trusty Does not exist

xenial Does not exist

upstream
Released (5.10~rc1)
bionic
Released (5.4.0-1033.35~18.04.1)
linux-gkeop-5.4
Launchpad, Ubuntu, Debian
focal Does not exist

groovy Does not exist

trusty Does not exist

xenial Does not exist

upstream
Released (5.10~rc1)
bionic
Released (5.4.0-1008.9~18.04.1)
linux-aws
Launchpad, Ubuntu, Debian
focal Not vulnerable
(powerpc only)
groovy Not vulnerable
(powerpc only)
bionic Not vulnerable
(powerpc only)
trusty Not vulnerable
(powerpc only)
upstream
Released (5.10~rc1)
xenial Not vulnerable
(powerpc only)
linux-hwe-5.8
Launchpad, Ubuntu, Debian
upstream
Released (5.10~rc1)
bionic Does not exist

focal
Released (5.8.0-44.50~20.04.1)
groovy Does not exist

trusty Does not exist

xenial Does not exist

linux-dell300x
Launchpad, Ubuntu, Debian
focal Does not exist

trusty Does not exist

xenial Does not exist

upstream
Released (5.10~rc1)
bionic
Released (4.15.0-1010.14)
groovy Does not exist

linux-gkeop
Launchpad, Ubuntu, Debian
focal Not vulnerable
(5.4.0-1008.9)
upstream
Released (5.10~rc1)
bionic Does not exist

groovy Does not exist

trusty Does not exist

xenial Does not exist

linux-oem-5.10
Launchpad, Ubuntu, Debian
focal Not vulnerable
(5.10.0-1008.9)
upstream
Released (5.10~rc1)
bionic Does not exist

groovy Does not exist

trusty Does not exist

xenial Does not exist

linux
Launchpad, Ubuntu, Debian
bionic
Released (4.15.0-129.132)
focal
Released (5.4.0-59.65)
groovy
Released (5.8.0-44.50)
trusty Ignored
(was needs-triage ESM criteria)
upstream
Released (5.10~rc1)
xenial
Released (4.4.0-201.233)
Patches:
Introduced by

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2

Fixed by bd59380c5ba4147dcbaad3e582b55ccfd120b764
linux-aws-5.3
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-aws-5.4
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-aws-hwe
Launchpad, Ubuntu, Debian
bionic Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Not vulnerable
(powerpc only)
linux-azure
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Not vulnerable
(powerpc only)
groovy Not vulnerable
(powerpc only)
trusty Not vulnerable
(powerpc only)
upstream
Released (5.10~rc1)
xenial Not vulnerable
(powerpc only)
linux-azure-4.15
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-azure-5.3
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-azure-5.4
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-gcp
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Not vulnerable
(powerpc only)
groovy Not vulnerable
(powerpc only)
trusty Does not exist

upstream
Released (5.10~rc1)
xenial Not vulnerable
(powerpc only)
linux-gcp-4.15
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-gcp-5.3
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-gcp-5.4
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-gcp-edge
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-gke-4.15
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-gke-5.3
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-hwe-5.4
Launchpad, Ubuntu, Debian
bionic
Released (5.4.0-59.65~18.04.1)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-hwe-edge
Launchpad, Ubuntu, Debian
bionic Ignored
(superseded by linux-hwe-5.4)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Ignored
(superseded by linux-hwe)
linux-kvm
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Not vulnerable
(powerpc only)
groovy Not vulnerable
(powerpc only)
trusty Does not exist

upstream
Released (5.10~rc1)
xenial Not vulnerable
(powerpc only)
linux-lts-trusty
Launchpad, Ubuntu, Debian
bionic Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-lts-xenial
Launchpad, Ubuntu, Debian
bionic Does not exist

focal Does not exist

groovy Does not exist

trusty
Released (4.4.0-201.233~14.04.1)
Available with Ubuntu Pro or Ubuntu Pro (Infra-only)
upstream
Released (5.10~rc1)
xenial Does not exist

linux-oem
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Not vulnerable
(powerpc only)
linux-oem-5.6
Launchpad, Ubuntu, Debian
bionic Does not exist

focal Not vulnerable
(powerpc only)
groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-oem-osp1
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-oracle
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Not vulnerable
(powerpc only)
groovy Not vulnerable
(powerpc only)
trusty Does not exist

upstream
Released (5.10~rc1)
xenial Not vulnerable
(powerpc only)
linux-oracle-5.0
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-oracle-5.3
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-oracle-5.4
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-raspi
Launchpad, Ubuntu, Debian
bionic Does not exist

focal Not vulnerable
(powerpc only)
groovy Not vulnerable
(powerpc only)
trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-raspi-5.4
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-raspi2
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Not vulnerable
(powerpc only)
groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Not vulnerable
(powerpc only)
linux-raspi2-5.3
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(powerpc only)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

linux-riscv
Launchpad, Ubuntu, Debian
bionic Does not exist

focal Not vulnerable
(powerpc only)
groovy Not vulnerable
(powerpc only)
trusty Does not exist

upstream
Released (5.10~rc1)
xenial Does not exist

Severity score breakdown

Parameter Value
Base score 6.7
Attack vector Local
Attack complexity Low
Privileges required High
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H