CVE-2021-47214
Linux Kernel Hugetlb Userfaultfd Memory Leak
Description
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.
INFO
Published Date :
April 10, 2024, 7:15 p.m.
Last Modified :
March 27, 2025, 9:05 p.m.
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Remotely Exploitable :
No
Impact Score :
3.6
Exploitability Score :
1.8
References to Advisories, Solutions, and Tools
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CVE-2021-47214.
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The following list is the news that have been mention
CVE-2021-47214 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-47214 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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Initial Analysis by [email protected]
Mar. 27, 2025
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-401 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:5.16:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.14 up to (excluding) 5.15.5 *cpe:2.3:o:linux:linux_kernel:5.13.13:*:*:*:*:*:*:* Added Reference Type CVE: https://git.kernel.org/stable/c/b5069d44e2fbc4a9093d005b3ef0949add3dd27e Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/b5069d44e2fbc4a9093d005b3ef0949add3dd27e Types: Patch Added Reference Type CVE: https://git.kernel.org/stable/c/cc30042df6fcc82ea18acf0dace831503e60a0b7 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/cc30042df6fcc82ea18acf0dace831503e60a0b7 Types: Patch -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 21, 2024
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/b5069d44e2fbc4a9093d005b3ef0949add3dd27e Added Reference https://git.kernel.org/stable/c/cc30042df6fcc82ea18acf0dace831503e60a0b7 -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 28, 2024
Action Type Old Value New Value -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 14, 2024
Action Type Old Value New Value -
CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Apr. 10, 2024
Action Type Old Value New Value Added Description 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. Added Reference kernel.org https://git.kernel.org/stable/c/b5069d44e2fbc4a9093d005b3ef0949add3dd27e [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/cc30042df6fcc82ea18acf0dace831503e60a0b7 [No types assigned]
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-47214 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-47214
weaknesses.