Bug 1585011 (CVE-2018-3665)
| Summary: | CVE-2018-3665 Kernel: FPU state information leakage via lazy FPU restore | ||
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| Product: | [Other] Security Response | Reporter: | Prasad Pandit <ppandit> |
| Component: | vulnerability | Assignee: | Red Hat Product Security <security-response-team> |
| Status: | CLOSED ERRATA | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | aarcange, airlied, andrew.schofield, aquini, bhu, blc, bskeggs, carnil, cperry, crrobins, cvsbot-xmlrpc, dhoward, dvlasenk, ewk, fhrbata, hdegoede, hkrzesin, hwkernel-mgr, iboverma, ichavero, itamar, jarodwilson, jbastian, jburrell, jcm, jforbes, jglisse, jkacur, john.j5live, jonathan, josef, jross, jstancek, jwboyer, kernel-maint, kernel-mgr, klaas, labbott, lgoncalv, linville, lwilliam, matt, mchehab, mcressma, mjg59, mlangsdo, mmilgram, mvanderw, nmurray, pbonzini, plougher, pmatouse, rcain, riehecky, rik.theys, rt-maint, rvrbovsk, security-response-team, skozina, steved, williams, yjog, ykopkova, yozone, zhijwang |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: |
A Floating Point Unit (FPU) state information leakage flaw was found in the way the Linux kernel saved and restored the FPU state during task switch. Linux kernels that follow the "Lazy FPU Restore" scheme are vulnerable to the FPU state information leakage issue. An unprivileged local attacker could use this flaw to read FPU state bits by conducting targeted cache side-channel attacks, similar to the Meltdown vulnerability disclosed earlier this year.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2019-06-10 10:27:13 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: | 1589047, 1589048, 1589049, 1589050, 1589051, 1589052, 1589053, 1590990, 1695833, 1695834 | ||
| Bug Blocks: | 1581207, 1589899, 1589900, 1589902, 1589903 | ||
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Description
Prasad Pandit
2018-06-01 06:52:38 UTC
Mitigation: RHEL-7 will automatically default to (safe) “eager” floating point register restore on Sandy Bridge and newer Intel processors. AMD processors are not affected. You can mitigate this issue on older processors by booting the kernel with the 'eagerfpu=on' parameter to enable eager FPU restore mode. In this mode FPU state is saved and restored for every task/context switch regardless of whether the current process invokes FPU instructions or not. The parameter does not affect performance negatively, and can be applied with no adverse effects to processors that are not affected. External References: https://access.redhat.com/solutions/3485131 http://www.openwall.com/lists/oss-security/2018/06/15/5 https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00145.html Statement: This issue affects the versions of the Linux kernel as shipped with Red Hat Enterprise Linux 5, 6, 7, and Red Hat Enterprise MRG 2. Future kernel updates for Red Hat Enterprise Linux 6, 7, and Red Hat Enterprise MRG 2 may address this issue. Red Hat Enterprise Linux 5 is now in Production 3 Phase of the support and maintenance life cycle. This has been rated as having Moderate security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/. Acknowledgments: Name: Julian Stecklina (Amazon.de), Thomas Prescher (cyberus-technology.de), Zdenek Sojka (sysgo.com) This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2018:1852 https://access.redhat.com/errata/RHSA-2018:1852 Is there a reason for eager only being default on Sandy Bridge and newer? (In reply to Klaas Demter from comment #11) > Is there a reason for eager only being default on Sandy Bridge and newer? On Sandy Bridge and newer CPUs RHEL-7 already defaults to 'eagerfpu' mode. Latest kernel update makes 'eagerfpu' as default on earlier Intel CPUs. Please use appropriate support channel for future questions: -> https://access.redhat.com/ Thank you. This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2018:1944 https://access.redhat.com/errata/RHSA-2018:1944 This issue has been addressed in the following products: Red Hat Enterprise MRG 2 Via RHSA-2018:2165 https://access.redhat.com/errata/RHSA-2018:2165 This issue has been addressed in the following products: Red Hat Enterprise Linux 6 Via RHSA-2018:2164 https://access.redhat.com/errata/RHSA-2018:2164 This issue has been addressed in the following products: Red Hat Enterprise Linux 7.4 Extended Update Support Via RHSA-2019:1170 https://access.redhat.com/errata/RHSA-2019:1170 This issue has been addressed in the following products: Red Hat Enterprise MRG 2 Via RHSA-2019:1190 https://access.redhat.com/errata/RHSA-2019:1190 |