CVE-2022-48769
Apple x86 Linux Kernel EFI v2.00 Runtime Service Avoidance Vulnerability
Description
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]/
INFO
Published Date :
June 20, 2024, 12:15 p.m.
Last Modified :
June 20, 2024, 12:43 p.m.
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Remotely Exploitable :
No
Impact Score :
Exploitability Score :
References to Advisories, Solutions, and Tools
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CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jun. 20, 2024
Action Type Old Value New Value Added Description 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]/ Added Reference kernel.org https://git.kernel.org/stable/c/b0f1cc093bc2493ac259c53766fd2b800e085807 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/3df52448978802ae15dcebf66beba1029df957b4 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/a4085859411c825c321c9b55b8a9dc5a128a6684 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/f5390cd0b43c2e54c7cf5506c7da4a37c5cef746 [No types assigned]
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2022-48769 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2022-48769
weaknesses.