CVE-2024-42233

filemap: replace pte_offset_map() with pte_offset_map_nolock()

Description

In the Linux kernel, the following vulnerability has been resolved: filemap: replace pte_offset_map() with pte_offset_map_nolock() The vmf->ptl in filemap_fault_recheck_pte_none() is still set from handle_pte_fault(). But at the same time, we did a pte_unmap(vmf->pte). After a pte_unmap(vmf->pte) unmap and rcu_read_unlock(), the page table may be racily changed and vmf->ptl maybe fails to protect the actual page table. Fix this by replacing pte_offset_map() with pte_offset_map_nolock(). As David said, the PTL pointer might be stale so if we continue to use it infilemap_fault_recheck_pte_none(), it might trigger UAF. Also, if the PTL fails, the issue fixed by commit 58f327f2ce80 ("filemap: avoid unnecessary major faults in filemap_fault()") might reappear.

3.3

CVSS

Severity: Low

CVSS 3.1 •

EPSS 0.03%

Affected: Linux Linux

References

Link	Tags
https://git.kernel.org/stable/c/6a6c2aec1a89506595801b4cf7e8eef035f33748	patch
https://git.kernel.org/stable/c/24be02a42181f0707be0498045c4c4b13273b16d	patch

Frequently Asked Questions

What is the severity of CVE-2024-42233?: CVE-2024-42233 has been scored as a low severity vulnerability.
How to fix CVE-2024-42233?: To fix CVE-2024-42233, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2024-42233 being actively exploited in the wild?: As for now, there are no information to confirm that CVE-2024-42233 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2024-42233?: CVE-2024-42233 affects Linux Linux, Linux Linux.

This platform uses data from the NIST NVD, MITRE CVE, MITRE CWE, First.org and CISA KEV but is not endorsed or certified by these entities. CVE is a registred trademark of the MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. CWE is a registred trademark of the MITRE Corporation and the authoritative source of CWE content is MITRE's CWE web site.