kernel: Multiple SSBD related flaws CVE-2020-10766 , CVE-2020-10767, CVE-2020-10768

[Wade Mealing <wmealing () redhat com>]

A number of flaws were discussed in the registers article this morning
( https://www.theregister.com/2020/06/09/linux_kernel_bugs_spectre )
which have been submitted for inclusion upstream already.

Listed below are the CVE's that Red Hat has assigned.  As far as I can
tell there are no existing  CVE assignments for these flaws. I have
not done adequate investigation to correctly identify affected
versions of the kernel, however this is a flaw in the fix for
CVE-2018-3639, affected systems would likely be affected by the flaws
listed below if they required the fix.

CVE-2020-10766
- Rogue cross-process SSBD shutdown. Linux scheduler logical bug
allows an attacker to turn off the SSBD protection.
https://lkml.org/lkml/2020/6/9/181

CVE-2020-10767
- Indirect Branch Prediction Barrier is force-disabled when STIBP is
unavailable or enhanced IBRS is available.
https://lkml.org/lkml/2020/6/9/183

CVE-2020-10768
-  Indirect branch speculation can be enabled after it was
force-disabled by the PR_SPEC_FORCE_DISABLE prctl command.
https://lkml.org/lkml/2020/6/9/184

The Red Hat Bugzillas for these flaws are

http://bugzilla.redhat.com/CVE-2020-10766
http://bugzilla.redhat.com/CVE-2020-10767
http://bugzilla.redhat.com/CVE-2020-10768

These  bugzillas are a work in progress and will be updated as I get
more time to correctly input adequate information.

Thank you.

-- 
Wade Mealing

Product Security - Kernel

Red Hat

wmealing () redhat com

TRIED. TESTED. TRUSTED.