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CVE-2017-1000405

Publication date 30 November 2017

Last updated 24 July 2024

Ubuntu priority

High

Why this priority?

Cvss 3 Severity Score

7.0 · High

Score breakdown

The Linux Kernel versions 2.6.38 through 4.14 have a problematic use of pmd_mkdirty() in the touch_pmd() function inside the THP implementation. touch_pmd() can be reached by get_user_pages(). In such case, the pmd will become dirty. This scenario breaks the new can_follow_write_pmd()'s logic - pmd can become dirty without going through a COW cycle. This bug is not as severe as the original "Dirty cow" because an ext4 file (or any other regular file) cannot be mapped using THP. Nevertheless, it does allow us to overwrite read-only huge pages. For example, the zero huge page and sealed shmem files can be overwritten (since their mapping can be populated using THP). Note that after the first write page-fault to the zero page, it will be replaced with a new fresh (and zeroed) thp.

From the Ubuntu Security Team

It was discovered that the Linux kernel did not properly handle copy-on- write of transparent huge pages. A local attacker could use this to cause a denial of service (application crashes) or possibly gain administrative privileges.

Read the notes from the security team

Status

Package Ubuntu Release Status
linux 17.10 artful
Fixed 4.13.0-19.22
17.04 zesty
Fixed 4.10.0-42.46
16.04 LTS xenial
Fixed 4.4.0-103.126
14.04 LTS trusty
Fixed 3.13.0-137.186
linux-armadaxp 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-aws 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial
Fixed 4.4.0-1043.52
14.04 LTS trusty
Fixed 4.4.0-1005.5
linux-azure 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial
Fixed 4.11.0-1016.16
14.04 LTS trusty
Not affected
linux-euclid 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-flo 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-gcp 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial
Fixed 4.13.0-1002.5
14.04 LTS trusty Not in release
linux-gke 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-goldfish 17.10 artful Not in release
17.04 zesty
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-grouper 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-hwe 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial
Fixed 4.10.0-42.46~16.04.1
14.04 LTS trusty Not in release
linux-hwe-edge 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial
Fixed 4.10.0-42.46~16.04.1
14.04 LTS trusty Not in release
linux-kvm 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial
Fixed 4.4.0-1012.17
14.04 LTS trusty Not in release
linux-linaro-omap 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-linaro-shared 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-linaro-vexpress 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-lts-quantal 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-lts-raring 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-lts-saucy 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-lts-trusty 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-lts-utopic 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-lts-vivid 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Ignored
linux-lts-wily 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-lts-xenial 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty
Fixed 4.4.0-103.126~14.04.1
linux-maguro 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-mako 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-manta 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-oem 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial
Fixed 4.13.0-1010.11
14.04 LTS trusty Not in release
linux-qcm-msm 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-raspi2 17.10 artful
Fixed 4.13.0-1008.8
17.04 zesty
Fixed 4.10.0-1023.26
16.04 LTS xenial
Fixed 4.4.0-1079.87
14.04 LTS trusty Not in release
linux-snapdragon 17.10 artful
Fixed 4.4.0-1081.86
17.04 zesty
Fixed 4.4.0-1081.86
16.04 LTS xenial
Fixed 4.4.0-1081.86
14.04 LTS trusty Not in release
linux-ti-omap4 17.10 artful Not in release
17.04 zesty Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release

Notes

smb

Added introducing commit as suggested by RH. We backported that into Trusty and later but not into Precise.

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
linux

Severity score breakdown

Parameter Value
Base score 7.0 · High
Attack vector Local
Attack complexity High
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

References

Related Ubuntu Security Notices (USN)

    • USN-3510-1
    • Linux kernel vulnerabilities
    • 8 December 2017
    • USN-3510-2
    • Linux kernel (Trusty HWE) vulnerabilities
    • 8 December 2017
    • USN-3511-1
    • Linux kernel (Azure) vulnerabilities
    • 8 December 2017
    • USN-3507-1
    • Linux kernel vulnerabilities
    • 7 December 2017
    • USN-3508-2
    • Linux kernel (HWE) vulnerabilities
    • 7 December 2017
    • USN-3507-2
    • Linux kernel (GCP) vulnerabilities
    • 8 December 2017
    • USN-3509-1
    • Linux kernel vulnerabilities
    • 7 December 2017
    • USN-3509-2
    • Linux kernel (Xenial HWE) vulnerabilities
    • 7 December 2017
    • USN-3508-1
    • Linux kernel vulnerabilities
    • 7 December 2017

Other references