GHSA-R5F6-W2PG-MF93
Vulnerability from github – Published: 2024-10-21 18:30 – Updated: 2024-11-07 21:31In the Linux kernel, the following vulnerability has been resolved:
mm/hugetlb: fix memfd_pin_folios free_huge_pages leak
memfd_pin_folios followed by unpin_folios fails to restore free_huge_pages if the pages were not already faulted in, because the folio refcount for pages created by memfd_alloc_folio never goes to 0. memfd_pin_folios needs another folio_put to undo the folio_try_get below:
memfd_alloc_folio() alloc_hugetlb_folio_nodemask() dequeue_hugetlb_folio_nodemask() dequeue_hugetlb_folio_node_exact() folio_ref_unfreeze(folio, 1); ; adds 1 refcount folio_try_get() ; adds 1 refcount hugetlb_add_to_page_cache() ; adds 512 refcount (on x86)
With the fix, after memfd_pin_folios + unpin_folios, the refcount for the (unfaulted) page is 512, which is correct, as the refcount for a faulted unpinned page is 513.
{
"affected": [],
"aliases": [
"CVE-2024-49964"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-10-21T18:15:17Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/hugetlb: fix memfd_pin_folios free_huge_pages leak\n\nmemfd_pin_folios followed by unpin_folios fails to restore free_huge_pages\nif the pages were not already faulted in, because the folio refcount for\npages created by memfd_alloc_folio never goes to 0. memfd_pin_folios\nneeds another folio_put to undo the folio_try_get below:\n\nmemfd_alloc_folio()\n alloc_hugetlb_folio_nodemask()\n dequeue_hugetlb_folio_nodemask()\n dequeue_hugetlb_folio_node_exact()\n folio_ref_unfreeze(folio, 1); ; adds 1 refcount\n folio_try_get() ; adds 1 refcount\n hugetlb_add_to_page_cache() ; adds 512 refcount (on x86)\n\nWith the fix, after memfd_pin_folios + unpin_folios, the refcount for the\n(unfaulted) page is 512, which is correct, as the refcount for a faulted\nunpinned page is 513.",
"id": "GHSA-r5f6-w2pg-mf93",
"modified": "2024-11-07T21:31:38Z",
"published": "2024-10-21T18:30:58Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-49964"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/59e081ff2e91bbf19b8c1ecb75b031f778858383"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c56b6f3d801d7ec8965993342bdd9e2972b6cb8e"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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