Your submission was sent successfully! Close

You have successfully unsubscribed! Close

CVE-2019-15794

Published: 8 November 2019

Overlayfs in the Linux kernel and shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, both replace vma->vm_file in their mmap handlers. On error the original value is not restored, and the reference is put for the file to which vm_file points. On upstream kernels this is not an issue, as no callers dereference vm_file following after call_mmap() returns an error. However, the aufs patchs change mmap_region() to replace the fput() using a local variable with vma_fput(), which will fput() vm_file, leading to a refcount underflow.

From the Ubuntu Security Team

Jann Horn discovered that the OverlayFS and ShiftFS Drivers in the Linux kernel did not properly handle reference counting during memory mapping operations when used in conjunction with AUFS. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.

Priority

Medium

Cvss 3 Severity Score

6.7

Score breakdown

Status

Package Release Status
linux
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.13.0-16.19)
disco
Released (5.0.0-37.40)
eoan
Released (5.3.0-24.26)
focal Not vulnerable
(5.4.0-9.12)
precise Ignored
(was needs-triage ESM criteria)
trusty Ignored
(was needs-triage ESM criteria)
upstream Needed

xenial Not vulnerable
(4.2.0-16.19)
Patches:
Introduced by

local-2019-15794-shift-break

Fixed by local-2019-15794-shift-fix
Introduced by

local-2019-15794-ovl-break

Fixed by local-2019-15794-ovl-fix
linux-aws
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.15.0-1001.1)
disco
Released (5.0.0-1022.25)
eoan
Released (5.3.0-1008.9)
focal Not vulnerable
(5.4.0-1005.5)
precise Does not exist

trusty Ignored
(was needs-triage ESM criteria)
upstream Needed

xenial Not vulnerable
(4.4.0-1001.10)
linux-aws-5.0
Launchpad, Ubuntu, Debian
bionic
Released (5.0.0-1022.25~18.04.1)
disco Does not exist

eoan Does not exist

focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Does not exist

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

disco Does not exist

eoan Does not exist

focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Not vulnerable
(4.15.0-1030.31~16.04.1)
linux-azure
Launchpad, Ubuntu, Debian
bionic
Released (5.0.0-1027.29~18.04.1)
disco
Released (5.0.0-1027.29)
eoan
Released (5.3.0-1008.9)
focal Not vulnerable
(5.4.0-1006.6)
precise Does not exist

trusty Ignored
(was needs-triage ESM criteria)
upstream Needed

xenial Not vulnerable
(4.11.0-1009.9)
linux-azure-5.3
Launchpad, Ubuntu, Debian
bionic
Released (5.3.0-1008.9~18.04.1)
disco Does not exist

eoan Does not exist

focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Does not exist

linux-azure-edge
Launchpad, Ubuntu, Debian
bionic Ignored
(was needs-triage now end-of-life)
disco Does not exist

eoan Does not exist

focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Ignored
(was needs-triage now end-of-life)
linux-gcp
Launchpad, Ubuntu, Debian
bionic
Released (5.0.0-1026.27~18.04.1)
disco
Released (5.0.0-1026.27)
eoan
Released (5.3.0-1009.10)
focal Not vulnerable
(5.4.0-1005.5)
precise Does not exist

trusty Does not exist

upstream Needed

xenial Not vulnerable
(4.10.0-1004.4)
linux-gcp-5.3
Launchpad, Ubuntu, Debian
bionic
Released (5.3.0-1009.10~18.04.1)
disco Does not exist

eoan Does not exist

focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Does not exist

linux-gcp-edge
Launchpad, Ubuntu, Debian
bionic Ignored
(was needs-triage now end-of-life)
disco Does not exist

eoan Does not exist

focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Does not exist

linux-gke-4.15
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.15.0-1030.32)
disco Does not exist

eoan Does not exist

focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Does not exist

linux-gke-5.0
Launchpad, Ubuntu, Debian
bionic
Released (5.0.0-1026.27~18.04.2)
disco Does not exist

eoan Does not exist

focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Does not exist

linux-gke-5.3
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(5.3.0-1011.12~18.04.1)
eoan Does not exist

focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Does not exist

linux-hwe
Launchpad, Ubuntu, Debian
bionic
Released (5.0.0-37.40~18.04.1)
disco Does not exist

eoan Does not exist

focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Not vulnerable
(4.8.0-36.36~16.04.1)
linux-hwe-edge
Launchpad, Ubuntu, Debian
bionic Ignored
(was pending \[5.3.0-24.26~18.04.2\] now end-of-life)
disco Does not exist

eoan Does not exist

focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Ignored
(was needs-triage now end-of-life)
linux-kvm
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.15.0-1002.2)
disco
Released (5.0.0-1023.25)
eoan
Released (5.3.0-1008.9)
focal Not vulnerable
(5.4.0-1004.4)
precise Does not exist

trusty Does not exist

upstream Needed

xenial Not vulnerable
(4.4.0-1004.9)
linux-lts-trusty
Launchpad, Ubuntu, Debian
bionic Does not exist

disco Does not exist

eoan Does not exist

focal Does not exist

precise Ignored
(was needs-triage ESM criteria)
trusty Does not exist

upstream Needed

xenial Does not exist

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

disco Does not exist

eoan Does not exist

focal Does not exist

precise Does not exist

trusty Ignored
(was needs-triage ESM criteria)
upstream Needed

xenial Does not exist

linux-oem
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.15.0-1002.3)
disco Not vulnerable
(4.15.0-1021.24)
eoan Not vulnerable
(4.15.0-1035.40)
focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Ignored
(was needs-triage now end-of-life)
linux-oem-5.6
Launchpad, Ubuntu, Debian
bionic Does not exist

eoan Does not exist

focal Not vulnerable
(5.4.0-1002.4)
precise Does not exist

trusty Does not exist

upstream Needed

xenial Does not exist

linux-oem-osp1
Launchpad, Ubuntu, Debian
bionic
Released (5.0.0-1030.34)
disco Ignored
(reached end-of-life)
eoan
Released (5.0.0-1030.34)
focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Does not exist

linux-oracle
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.15.0-1007.9)
disco
Released (5.0.0-1008.13)
eoan
Released (5.3.0-1007.8)
focal Not vulnerable
(5.4.0-1005.5)
precise Does not exist

trusty Does not exist

upstream Needed

xenial Not vulnerable
(4.15.0-1007.9~16.04.1)
linux-oracle-5.0
Launchpad, Ubuntu, Debian
bionic
Released (5.0.0-1008.13~18.04.1)
disco Does not exist

eoan Does not exist

focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Does not exist

linux-oracle-5.3
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(5.3.0-1011.12~18.04.1)
eoan Does not exist

focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Does not exist

linux-raspi2
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.13.0-1005.5)
disco
Released (5.0.0-1023.24)
eoan
Released (5.3.0-1014.16)
focal Ignored
(was needed now end-of-life)
precise Does not exist

trusty Does not exist

upstream Needed

xenial Not vulnerable
(4.2.0-1013.19)
linux-raspi2-5.3
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(5.3.0-1017.19~18.04.1)
eoan Does not exist

focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Does not exist

linux-snapdragon
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.4.0-1077.82)
disco Ignored
(was pending \[5.0.0-1027.29\] now end-of-life)
eoan Does not exist

focal Does not exist

precise Does not exist

trusty Does not exist

upstream Needed

xenial Not vulnerable
(4.4.0-1012.12)

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