CVE-2016-6213

Published: 14 July 2016

fs/namespace.c in the Linux kernel before 4.9 does not restrict how many mounts may exist in a mount namespace, which allows local users to cause a denial of service (memory consumption and deadlock) via MS_BIND mount system calls, as demonstrated by a loop that triggers exponential growth in the number of mounts.

From the Ubuntu security team

CAI Qian discovered that shared bind mounts in a mount namespace exponentially added entries without restriction to the Linux kernel's mount table. A local attacker could use this to cause a denial of service (system crash).

Priority

Medium

CVSS 3 base score: 4.7

Status

Package Release Status
linux
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
Patches:
Introduced by 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Fixed by d29216842a85c7970c536108e093963f02714498
linux-armadaxp
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
This package is not directly supported by the Ubuntu Security Team
linux-aws
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-flo
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-gke
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-goldfish
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-grouper
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-hwe
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-hwe-edge
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-linaro-omap
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-linaro-shared
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-linaro-vexpress
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-lts-quantal
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
This package is not directly supported by the Ubuntu Security Team
linux-lts-raring
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-lts-saucy
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
This package is not directly supported by the Ubuntu Security Team
linux-lts-trusty
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-lts-utopic
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-lts-vivid
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-lts-wily
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-lts-xenial
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-maguro
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-mako
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-manta
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-qcm-msm
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-raspi2
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-snapdragon
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)
linux-ti-omap4
Launchpad, Ubuntu, Debian
Upstream
Released (4.9~rc1)

Notes

AuthorNote
jdstrand
android kernels (flo, goldfish, grouper, maguro, mako and manta) are
not supported on the Ubuntu Touch 14.10 and earlier preview kernels
linux-lts-saucy no longer receives official support
linux-lts-quantal no longer receives official support
sbeattie
The fix for this issue introduces a new
/proc/sys/fs/mount-max sysctl that can be used to adjust the limit

References