ghsa-m7cw-h386-9wgp
Vulnerability from github
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.
{
"affected": [],
"aliases": [
"CVE-2024-35872"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-05-19T09:15:08Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/secretmem: fix GUP-fast succeeding on secretmem folios\n\nfolio_is_secretmem() currently relies on secretmem folios being LRU\nfolios, to save some cycles.\n\nHowever, folios might reside in a folio batch without the LRU flag set, or\ntemporarily have their LRU flag cleared. Consequently, the LRU flag is\nunreliable for this purpose.\n\nIn particular, this is the case when secretmem_fault() allocates a fresh\npage and calls filemap_add_folio()-\u003efolio_add_lru(). The folio might be\nadded to the per-cpu folio batch and won\u0027t get the LRU flag set until the\nbatch was drained using e.g., lru_add_drain().\n\nConsequently, folio_is_secretmem() might not detect secretmem folios and\nGUP-fast can succeed in grabbing a secretmem folio, crashing the kernel\nwhen we would later try reading/writing to the folio, because the folio\nhas been unmapped from the directmap.\n\nFix it by removing that unreliable check.",
"id": "GHSA-m7cw-h386-9wgp",
"modified": "2024-05-19T09:34:46Z",
"published": "2024-05-19T09:34:46Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-35872"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/201e4aaf405dfd1308da54448654053004c579b5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/43fad1d0284de30159661d0badfc3cbaf7e6f8f8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/65291dcfcf8936e1b23cfd7718fdfde7cfaf7706"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6564b014af92b677c1f07c44d7f5b595d589cf6e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9c2b4b657739ecda38e3b383354a29566955ac48"
}
],
"schema_version": "1.4.0",
"severity": []
}
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- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
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- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.