1.2 KiB
CVE-2024-42233
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 fromhandle_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 tablemay be racily changed and vmf->ptl maybe fails to protect the actual pagetable. Fix this by replacing pte_offset_map() withpte_offset_map_nolock().As David said, the PTL pointer might be stale so if we continue to useit infilemap_fault_recheck_pte_none(), it might trigger UAF. Also, ifthe PTL fails, the issue fixed by commit 58f327f2ce80 ("filemap: avoidunnecessary major faults in filemap_fault()") might reappear.
POC
Reference
No PoCs from references.