CVE-2023-52504

See a problem?
Please try reporting it to the source first.
Source
https://nvd.nist.gov/vuln/detail/CVE-2023-52504
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2023-52504.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2023-52504
Downstream
Related
Published
2024-03-02T22:15:47Z
Modified
2025-08-09T20:01:25Z
Severity
  • 7.1 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H CVSS Calculator
Summary
[none]
Details

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

x86/alternatives: Disable KASAN in apply_alternatives()

Fei has reported that KASAN triggers during apply_alternatives() on a 5-level paging machine:

BUG: KASAN: out-of-bounds in rcu_is_watching()
Read of size 4 at addr ff110003ee6419a0 by task swapper/0/0
...
__asan_load4()
rcu_is_watching()
trace_hardirqs_on()
text_poke_early()
apply_alternatives()
...

On machines with 5-level paging, cpufeatureenabled(X86FEATURELA57) gets patched. It includes KASAN code, where KASANSHADOWSTART depends on _VIRTUALMASKSHIFT, which is defined with cpufeature_enabled().

KASAN gets confused when applyalternatives() patches the KASANSHADOWSTART users. A test patch that makes KASANSHADOWSTART static, by replacing _VIRTUALMASKSHIFT with 56, works around the issue.

Fix it for real by disabling KASAN while the kernel is patching alternatives.

[ mingo: updated the changelog ]

References

Affected packages