Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: mm/page_table_check: skip special zero mappings page_table_check_set() and page_table_check_clear() account mappings based on PageAnon(). Shared zero-page PTEs and huge zero PMDs are special mappings, but page_table_check can still account them as file-backed pages. An unprivileged process can populate enough zero mappings to overflow file_map_count and hit the existing BUG_ON(). The PTE path can do this with the shared zero page, and the PMD path can do the same with huge zero mappings. Skip special zero mappings in the user page-table accounting paths. Keep the PTE-side pte_special() check, and identify huge zero PMDs from the mapped folio instead of pmd_special(). That covers architectures where pmd_special() is a no-op without adding huge_zero_pfn checks to the generic counter helpers.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected df4e817b710809425d899340dbfa8504a3ca4ba5 before f6cf9832e677ec07b1675782bd2bad472cfd3cdc; affected df4e817b710809425d899340dbfa8504a3ca4ba5 before 51e16e5adadaa78b56f31a1cb02eb7267787625e; affected df4e817b710809425d899340dbfa8504a3ca4ba5 before 7755be923e325dc300f4b0c3e1ad7e91b28b3cb9; affected df4e817b710809425d899340dbfa8504a3ca4ba5 before b726eb3c94d23e09da0e0f46b0fa09fb2b5d99cc; affected df4e817b710809425d899340dbfa8504a3ca4ba5 before 8db4bab826ccc9ec10fa41736a48031cd338d392 |
| Linux / Linux | affected 5.17; unaffected 0 before 5.17; unaffected 6.6.160 through 6.6.*; unaffected 6.12.114 through 6.12.*; unaffected 6.18.46 through 6.18.*; unaffected 7.1.9 through 7.1.*; unaffected 7.2 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/f6cf9832e677ec07b1675782bd2bad472cfd3cdc
- https://git.kernel.org/stable/c/51e16e5adadaa78b56f31a1cb02eb7267787625e
- https://git.kernel.org/stable/c/7755be923e325dc300f4b0c3e1ad7e91b28b3cb9
- https://git.kernel.org/stable/c/b726eb3c94d23e09da0e0f46b0fa09fb2b5d99cc
- https://git.kernel.org/stable/c/8db4bab826ccc9ec10fa41736a48031cd338d392