CVE-2021-47214 (GCVE-0-2021-47214)

Vulnerability from cvelistv5 – Published: 2024-04-10 19:01 – Updated: 2026-05-23 15:19
VLAI
Title
hugetlb, userfaultfd: fix reservation restore on userfaultfd error
Summary
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.
Severity
No CVSS data available.
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-04-12 16:35 UTC
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: c7b1850dfb41d0b4154aca8dbc04777fbd75616f , < b5069d44e2fbc4a9093d005b3ef0949add3dd27e (git)
Affected: c7b1850dfb41d0b4154aca8dbc04777fbd75616f , < cc30042df6fcc82ea18acf0dace831503e60a0b7 (git)
Affected: 515b6124df6a84c957c5cc6bb6e8309dae7b1e9c (git)
Affected: 5.13.13 , < 5.14 (semver)
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Linux Linux Affected: 5.14
Unaffected: 0 , < 5.14 (semver)
Unaffected: 5.15.5 , ≤ 5.15.* (semver)
Unaffected: 5.16 , ≤ * (original_commit_for_fix)
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