CVE-2016-9644

Published: 27 November 2016

The __get_user_asm_ex macro in arch/x86/include/asm/uaccess.h in the Linux kernel 4.4.22 through 4.4.28 contains extended asm statements that are incompatible with the exception table, which allows local users to obtain root access on non-SMEP platforms via a crafted application. NOTE: this vulnerability exists because of incorrect backporting of the CVE-2016-9178 patch to older kernels.

From the Ubuntu security team

It was discovered that the __get_user_asm_ex implementation in the Linux kernel for x86/x86_64 contained extended asm statements that were incompatible with the exception table. A local attacker could use this to gain administrative privileges.

Priority

Medium

CVSS 3 base score: 7.8

Status

Package Release Status
linux
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
Patches:
Introduced by 1c109fabbd51863475cd12ac206bdd249aee35af
Fixed by 548acf19234dbda5a52d5a8e7e205af46e9da840
linux-armadaxp
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
This package is not directly supported by the Ubuntu Security Team
linux-aws
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-flo
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-gke
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-goldfish
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-grouper
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-hwe
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-hwe-edge
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-linaro-omap
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-linaro-shared
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-linaro-vexpress
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-lts-quantal
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
This package is not directly supported by the Ubuntu Security Team
linux-lts-raring
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-lts-saucy
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
This package is not directly supported by the Ubuntu Security Team
linux-lts-trusty
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-lts-utopic
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-lts-vivid
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-lts-wily
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-lts-xenial
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-maguro
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-mako
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-manta
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-qcm-msm
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-raspi2
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-snapdragon
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)
linux-ti-omap4
Launchpad, Ubuntu, Debian
Upstream
Released (4.8~rc7)

Notes

AuthorNote
sbeattie
1c109fabbd51863475cd12ac206bdd249aee35af
was applied to the 4.4 stable series (in xenial
as 1c109fabbd51863475cd12ac206bdd249aee35af) to fix
CVE-2016-9178, and then got reverted from stable in 4.4.30
(in xenial as 2da13e7f631bb13658e00e61fdea050da25e69e7).
548acf19234dbda5a52d5a8e7e205af46e9da840 was
also very briefly applied to stable in 4.4.29, but
reverted at the same time due to problems (in xenial as
102d19689b2dd4f639a14dfd3f52ce19b5d7bb17). For xenial/4.4
derived kernels, this CVE is fixed with the reversion in
2da13e7f631bb13658e00e61fdea050da25e69e7. However, this leaves
CVE-2016-9178 unfixed.

References