Bug 1516514 (CVE-2017-1000405)
Summary: | CVE-2017-1000405 kernel: pmd can become dirty without going through a COW cycle | ||
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Product: | [Other] Security Response | Reporter: | Andrej Nemec <anemec> |
Component: | vulnerability | Assignee: | Red Hat Product Security <security-response-team> |
Status: | CLOSED ERRATA | QA Contact: | |
Severity: | high | Docs Contact: | |
Priority: | high | ||
Version: | unspecified | CC: | airlied, ajax, aquini, bhu, blc, bskeggs, cperry, crecklin, dhoward, ewk, fhrbata, hdegoede, hkrzesin, hwkernel-mgr, iboverma, ichavero, itamar, jarodwilson, jeremy, jforbes, jglisse, jkacur, john.j5live, jonathan, josef, jross, jwboyer, kent, kernel-maint, kernel-mgr, labbott, lgoncalv, linville, matt, mchehab, mcressma, mjg59, mlangsdo, mvermaes, nmurray, plougher, pmatouse, rt-maint, rvrbovsk, security-response-team, steved, williams, wmealing |
Target Milestone: | --- | Keywords: | Security |
Target Release: | --- | ||
Hardware: | All | ||
OS: | Linux | ||
Whiteboard: | |||
Fixed In Version: | Doc Type: | If docs needed, set a value | |
Doc Text: |
A flaw was found in the patches used to fix the 'dirtycow' vulnerability (CVE-2016-5195). An attacker, able to run local code, can exploit a race condition in transparent huge pages to modify usually read-only huge pages.
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Story Points: | --- |
Clone Of: | Environment: | ||
Last Closed: | 2019-06-08 03:31:49 UTC | Type: | --- |
Regression: | --- | Mount Type: | --- |
Documentation: | --- | CRM: | |
Verified Versions: | Category: | --- | |
oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
Cloudforms Team: | --- | Target Upstream Version: | |
Embargoed: | |||
Bug Depends On: | 1517816, 1518490, 1518491, 1518492, 1518493, 1518494, 1518495, 1518611, 1518612, 1519115 | ||
Bug Blocks: | 1516515 |
Description
Andrej Nemec
2017-11-22 19:34:42 UTC
Acknowledgments: Name: Eylon Ben Yaakov, Daniel Shapiro Statement: From the initial flaw description released, this issue does not affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 5, 6, 7 and Red Hat Enterprise MRG 2. They do not contain the upstream commit (8310d48b125d19fcd9521d83b8293e63eb1646aa) which allows the race condition. This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 7 for ARM and Red Hat Enterprise Linux for Power LE. Future Linux kernel updates for the respective releases may address this issue. For further information please refer to the vulnerability article in the Customer Portal: https://access.redhat.com/security/vulnerabilities/3253921 What is Red Hat Enterprise Linux 7 for ARM, Red Hat Enterprise Linux for Power LE, and kernel-alt: The kernel-alt package as shipped with Red Hat Enterprise Linux 7 for ARM and Red Hat Enterprise Linux for Power LE is an updated kernel intended to support new architectures not available at the time of Red Hat Enterprise Linux 7 original shipping. The new kernel version provided by the kernel-alt packages is based on upstream version 4.11 . The offering is distributed with other updated packages but most of the userspace is the standard Red Hat Enterprise Linux 7 Server RPMs. For more information please refer to: https://access.redhat.com/articles/3158541 https://access.redhat.com/articles/3158511 Mitigation: Disabling the use of zero page: It is possible to prevent the zero page from being mapped as a huge page, by modifying a configuration tunable in the /sys directory as shown below. This prevents the flaw from being exercised in this method. # echo 0 > /sys/kernel/mm/transparent_hugepage/use_zero_page Disabling huge pages: It is possible to mitigate this flaw by disabling hugepages on a system. Some user applications may require hugepages to be performant, and may suffer a performance penalty when running without hugepages. Red Hat has existing solutions created instructing how to disable transparent How to disable transparent hugepages (THP) on Red Hat Enterprise Linux 7 https://access.redhat.com/solutions/1320153 If your application may require transparent huge pages, please consult your software vendor to confirm. Created kernel tracking bugs for this issue: Affects: fedora-all [bug 1519115] This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2018:0180 https://access.redhat.com/errata/RHSA-2018:0180 |