Bug 1679326 (CVE-2019-17346) - CVE-2019-17346 xen: xsa292: insufficient TLB flushing when using PCID
Summary: CVE-2019-17346 xen: xsa292: insufficient TLB flushing when using PCID
Keywords:
Status: CLOSED WONTFIX
Alias: CVE-2019-17346
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1685577
Blocks:
TreeView+ depends on / blocked
 
Reported: 2019-02-20 21:52 UTC by Pedro Sampaio
Modified: 2019-11-12 09:00 UTC (History)
13 users (show)

Fixed In Version:
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Last Closed: 2019-06-10 10:48:27 UTC


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Description Pedro Sampaio 2019-02-20 21:52:35 UTC
Use of Process Context Identifiers (PCID) was introduced into Xen in
order to improve performance after XSA-254 (and in particular its
Meltdown sub-issue). This enablement implied changes to the TLB
flushing logic. The particular case of context switch to a vCPU of a
PCID-enabled guest left open a time window between the full TLB flush,
and the actual address space switch, during which additional TLB
entries (from the address space about to be switched away from) can be
accumulated, which will not subsequently be purged.

Comment 1 Andrej Nemec 2019-03-05 14:15:42 UTC
References:

https://seclists.org/oss-sec/2019/q1/161

Comment 2 Andrej Nemec 2019-03-05 14:26:40 UTC
Created xen tracking bugs for this issue:

Affects: fedora-all [bug 1685577]


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