Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | >= 5.14, < 5.15.5 |
Related Weaknesses (CWE)
References
- https://git.kernel.org/stable/c/b5069d44e2fbc4a9093d005b3ef0949add3dd27ePatch
- https://git.kernel.org/stable/c/cc30042df6fcc82ea18acf0dace831503e60a0b7Patch
- https://git.kernel.org/stable/c/b5069d44e2fbc4a9093d005b3ef0949add3dd27ePatch
- https://git.kernel.org/stable/c/cc30042df6fcc82ea18acf0dace831503e60a0b7Patch
FAQ
What is CVE-2021-47214?
CVE-2021-47214 is a vulnerability with a CVSS score of 5.5 (MEDIUM). 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()...
How severe is CVE-2021-47214?
CVE-2021-47214 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-47214?
Check the references section above for vendor advisories and patch information. Affected products include: Linux Linux Kernel.