In the Linux kernel, the following vulnerability has been resolved:
efi: runtime: avoid EFIv2 runtime services on Apple x86 machines
Aditya reports [0] that his recent MacbookPro crashes in the firmware
when using the variable services at runtime. The culprit appears to be a
call to QueryVariableInfo(), which we did not use to call on Apple x86
machines in the past as they only upgraded from EFI v1.10 to EFI v2.40
firmware fairly recently, and QueryVariableInfo() (along with
UpdateCapsule() et al) was added in EFI v2.00.
The only runtime service introduced in EFI v2.00 that we actually use in
Linux is QueryVariableInfo(), as the capsule based ones are optional,
generally not used at runtime (all the LVFS/fwupd firmware update
infrastructure uses helper EFI programs that invoke capsule update at
boot time, not runtime), and not implemented by Apple machines in the
first place. QueryVariableInfo() is used to 'safely' set variables,
i.e., only when there is enough space. This prevents machines with buggy
firmwares from corrupting their NVRAMs when they run out of space.
Given that Apple machines have been using EFI v1.10 services only for
the longest time (the EFI v2.0 spec was released in 2006, and Linux
support for the newly introduced runtime services was added in 2011, but
the MacbookPro12,1 released in 2015 still claims to be EFI v1.10 only),
let's avoid the EFI v2.0 ones on all Apple x86 machines.
[0] https://lore.kernel.org/all/[email protected]/
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Affected Vendors & Products
References
History
Wed, 11 Sep 2024 13:30:00 +0000
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MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2024-06-20T11:13:44.469Z
Updated: 2024-12-19T08:07:22.847Z
Reserved: 2024-06-20T11:09:39.061Z
Link: CVE-2022-48769
Vulnrichment
Updated: 2024-08-03T15:25:01.538Z
NVD
Status : Awaiting Analysis
Published: 2024-06-20T12:15:14.870
Modified: 2024-11-21T07:33:59.150
Link: CVE-2022-48769
Redhat