Bug 2323925 (CVE-2024-50112)

Summary:	CVE-2024-50112 kernel: x86/lam: Disable ADDRESS_MASKING in most cases
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	dfreiber, drow, jburrell, vkumar
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Bug Depends On:	2324033
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Description OSIDB Bzimport 2024-11-05 18:02:35 UTC

In the Linux kernel, the following vulnerability has been resolved:

x86/lam: Disable ADDRESS_MASKING in most cases

Linear Address Masking (LAM) has a weakness related to transient
execution as described in the SLAM paper[1]. Unless Linear Address
Space Separation (LASS) is enabled this weakness may be exploitable.

Until kernel adds support for LASS[2], only allow LAM for COMPILE_TEST,
or when speculation mitigations have been disabled at compile time,
otherwise keep LAM disabled.

There are no processors in market that support LAM yet, so currently
nobody is affected by this issue.

[1] SLAM: https://download.vusec.net/papers/slam_sp24.pdf
[2] LASS: https://lore.kernel.org/lkml/20230609183632.48706-1-alexander.shishkin@linux.intel.com/

[ dhansen: update SPECULATION_MITIGATIONS -> CPU_MITIGATIONS ]

Comment 1 Robb Gatica 2024-11-05 21:16:52 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024110555-CVE-2024-50112-37de@gregkh/T