CVE-2024-35872
In the Linux kernel, the following vulnerability has been resolved: mm/secretmem: fix GUP-fast succeeding on secretmem folios folio_is_secretmem() currently relies on secretmem folios being LRU folios, to save some cycles.
Does this matter?
Lower severity and a low EPSS score (0.24%). Track it; it rarely justifies an emergency change on its own.
Description
In the Linux kernel, the following vulnerability has been resolved: mm/secretmem: fix GUP-fast succeeding on secretmem folios folio_is_secretmem() currently relies on secretmem folios being LRU folios, to save some cycles. However, folios might reside in a folio batch without the LRU flag set, or temporarily have their LRU flag cleared. Consequently, the LRU flag is unreliable for this purpose. In particular, this is the case when secretmem_fault() allocates a fresh page and calls filemap_add_folio()->folio_add_lru(). The folio might be added to the per-cpu folio batch and won't get the LRU flag set until the batch was drained using e.g., lru_add_drain(). Consequently, folio_is_secretmem() might not detect secretmem folios and GUP-fast can succeed in grabbing a secretmem folio, crashing the kernel when we would later try reading/writing to the folio, because the folio has been unmapped from the directmap. Fix it by removing that unreliable check.
- CVSS 3.1
- 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.24% probability · 15th percentile
- CISA KEV
- Not listed
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/201e4aaf405dfd1308da54448654053004c579b5Patch
- https://git.kernel.org/stable/c/43fad1d0284de30159661d0badfc3cbaf7e6f8f8Patch
- https://git.kernel.org/stable/c/65291dcfcf8936e1b23cfd7718fdfde7cfaf7706Patch
- https://git.kernel.org/stable/c/6564b014af92b677c1f07c44d7f5b595d589cf6ePatch
- https://git.kernel.org/stable/c/9c2b4b657739ecda38e3b383354a29566955ac48Patch
- https://git.kernel.org/stable/c/201e4aaf405dfd1308da54448654053004c579b5Patch
- https://git.kernel.org/stable/c/43fad1d0284de30159661d0badfc3cbaf7e6f8f8Patch
- https://git.kernel.org/stable/c/65291dcfcf8936e1b23cfd7718fdfde7cfaf7706Patch
- https://git.kernel.org/stable/c/6564b014af92b677c1f07c44d7f5b595d589cf6ePatch
- https://git.kernel.org/stable/c/9c2b4b657739ecda38e3b383354a29566955ac48Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.