Incomplete Cleanup Affecting kernel-uek-debug-devel package, versions <0:5.15.0-300.163.18.7.el9uek


Severity

Recommended
high

Based on Oracle Linux security rating.

Threat Intelligence

EPSS
0.04% (6th percentile)

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  • Snyk IDSNYK-ORACLE9-KERNELUEKDEBUGDEVEL-8236980
  • published22 Oct 2024
  • disclosed15 Oct 2024

Introduced: 15 Oct 2024

CVE-2024-47674  (opens in a new tab)
CWE-459  (opens in a new tab)
First added by Snyk

How to fix?

Upgrade Oracle:9 kernel-uek-debug-devel to version 0:5.15.0-300.163.18.7.el9uek or higher.
This issue was patched in ELSA-2024-12830.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-uek-debug-devel package and not the kernel-uek-debug-devel package as distributed by Oracle. See How to fix? for Oracle:9 relevant fixed versions and status.

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

mm: avoid leaving partial pfn mappings around in error case

As Jann points out, PFN mappings are special, because unlike normal memory mappings, there is no lifetime information associated with the mapping - it is just a raw mapping of PFNs with no reference counting of a 'struct page'.

That's all very much intentional, but it does mean that it's easy to mess up the cleanup in case of errors. Yes, a failed mmap() will always eventually clean up any partial mappings, but without any explicit lifetime in the page table mapping itself, it's very easy to do the error handling in the wrong order.

In particular, it's easy to mistakenly free the physical backing store before the page tables are actually cleaned up and (temporarily) have stale dangling PTE entries.

To make this situation less error-prone, just make sure that any partial pfn mapping is torn down early, before any other error handling.

CVSS Scores

version 3.1