Bug 2313142 (CVE-2024-46794)

Summary:	CVE-2024-46794 kernel: x86/tdx: Fix data leak in mmio_read()
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
Target Release:	---
Hardware:	All
OS:	Linux
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
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Bug Depends On:	2313271
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Description OSIDB Bzimport 2024-09-18 08:23:21 UTC

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

x86/tdx: Fix data leak in mmio_read()

The mmio_read() function makes a TDVMCALL to retrieve MMIO data for an
address from the VMM.

Sean noticed that mmio_read() unintentionally exposes the value of an
initialized variable (val) on the stack to the VMM.

This variable is only needed as an output value. It did not need to be
passed to the VMM in the first place.

Do not send the original value of *val to the VMM.

[ dhansen: clarify what 'val' is used for. ]

Comment 1 Michal Findra 2024-09-18 12:22:55 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024091854-CVE-2024-46794-9f64@gregkh/T