CVE-2025-40272

Description

In the Linux kernel, the following vulnerability has been resolved: mm/secretmem: fix use-after-free race in fault handler When a page fault occurs in a secret memory file created with `memfd_secret(2)`, the kernel will allocate a new folio for it, mark the underlying page as not-present in the direct map, and add it to the file mapping. If two tasks cause a fault in the same page concurrently, both could end up allocating a folio and removing the page from the direct map, but only one would succeed in adding the folio to the file mapping. The task that failed undoes the effects of its attempt by (a) freeing the folio again and (b) putting the page back into the direct map. However, by doing these two operations in this order, the page becomes available to the allocator again before it is placed back in the direct mapping. If another task attempts to allocate the page between (a) and (b), and the kernel tries to access it via the direct map, it would result in a supervisor not-present page fault. Fix the ordering to restore the direct map before the folio is freed.

PUBLISHED Reserved 2025-04-16 | Published 2025-12-06 | Updated 2025-12-06 | Assigner Linux

Product status

References

git.kernel.org/...c/bb1c19636aedae39360e6fdbcaef4f2bcff25785

git.kernel.org/...c/1e4643d6628edf9c0047b1f8f5bc574665025acb

git.kernel.org/...c/42d486d35a4143cc37fc72ee66edc99d942dd367

git.kernel.org/...c/52f2d5cf33de9a8f5e72bbb0ed38282ae0bc4649

git.kernel.org/...c/4444767e625da46009fc94a453fd1967b80ba047

git.kernel.org/...c/6f86d0534fddfbd08687fa0f01479d4226bc3c3d

cve.org (CVE-2025-40272)

nvd.nist.gov (CVE-2025-40272)

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