Vulnerability Details CVE-2024-42233
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 7.0%
CVSS Severity
CVSS v3 Score 3.3
References
Products affected by CVE-2024-42233
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cpe:2.3:o:linux:linux_kernel:6.9
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cpe:2.3:o:linux:linux_kernel:6.9.1
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cpe:2.3:o:linux:linux_kernel:6.9.2
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cpe:2.3:o:linux:linux_kernel:6.9.3
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cpe:2.3:o:linux:linux_kernel:6.9.4
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cpe:2.3:o:linux:linux_kernel:6.9.5
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cpe:2.3:o:linux:linux_kernel:6.9.6
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cpe:2.3:o:linux:linux_kernel:6.9.7
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cpe:2.3:o:linux:linux_kernel:6.9.8
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cpe:2.3:o:linux:linux_kernel:6.9.9