gsd-2021-47214
Vulnerability from gsd
Modified
2024-04-11 05:05
Details
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.
Aliases
{
"gsd": {
"metadata": {
"exploitCode": "unknown",
"remediation": "unknown",
"reportConfidence": "confirmed",
"type": "vulnerability"
},
"osvSchema": {
"aliases": [
"CVE-2021-47214"
],
"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": "GSD-2021-47214",
"modified": "2024-04-11T05:05:09.682284Z",
"schema_version": "1.4.0"
}
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"value": "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."
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"descriptions": [
{
"lang": "en",
"value": "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": "CVE-2021-47214",
"lastModified": "2024-04-10T19:49:51.183",
"metrics": {},
"published": "2024-04-10T19:15:48.680",
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{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/b5069d44e2fbc4a9093d005b3ef0949add3dd27e"
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"url": "https://git.kernel.org/stable/c/cc30042df6fcc82ea18acf0dace831503e60a0b7"
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"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Awaiting Analysis"
}
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}
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
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- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- 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.
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