ghsa-rr47-vpr9-84rm
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
hugetlb, userfaultfd: fix reservation restore on userfaultfd error
Currently in the is_continue case in hugetlb_mcopy_atomic_pte(), if we bail out using "goto out_release_unlock;" in the cases where idx >= size, or !huge_pte_none(), the code will detect that new_pagecache_page == false, and so call restore_reserve_on_error(). In this case I see restore_reserve_on_error() delete the reservation, and the following call to remove_inode_hugepages() will increment h->resv_hugepages causing a 100% reproducible leak.
We should treat the is_continue case similar to adding a page into the pagecache and set new_pagecache_page to true, to indicate that there is no reservation to restore on the error path, and we need not call restore_reserve_on_error(). Rename new_pagecache_page to page_in_pagecache to make that clear.
{
"affected": [],
"aliases": [
"CVE-2021-47214"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-04-10T19:15:48Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nhugetlb, userfaultfd: fix reservation restore on userfaultfd error\n\nCurrently in the is_continue case in hugetlb_mcopy_atomic_pte(), if we\nbail out using \"goto out_release_unlock;\" in the cases where idx \u003e=\nsize, or !huge_pte_none(), the code will detect that new_pagecache_page\n== false, and so call restore_reserve_on_error(). In this case I see\nrestore_reserve_on_error() delete the reservation, and the following\ncall to remove_inode_hugepages() will increment h-\u003eresv_hugepages\ncausing a 100% reproducible leak.\n\nWe should treat the is_continue case similar to adding a page into the\npagecache and set new_pagecache_page to true, to indicate that there is\nno reservation to restore on the error path, and we need not call\nrestore_reserve_on_error(). Rename new_pagecache_page to\npage_in_pagecache to make that clear.",
"id": "GHSA-rr47-vpr9-84rm",
"modified": "2024-04-10T21:30:32Z",
"published": "2024-04-10T21:30:32Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-47214"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b5069d44e2fbc4a9093d005b3ef0949add3dd27e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/cc30042df6fcc82ea18acf0dace831503e60a0b7"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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