In the Linux kernel, the following vulnerability has been resolved: x86/mm/pat: fix VM_PAT handling in COW mappings PAT handling won\'t do the right thing in COW mappings: the first PTE (or, in fact, all PTEs) can be replaced during write faults to point at anon folios. Reliably recovering the correct PFN and cachemode using follow_phys() from PTEs will not work in COW mappings. Using follow_phys(), we might just get the address+protection of the anon folio (which is very wrong), or fail on swap/nonswap entries, failing follow_phys() and triggering a WARN_ON_ONCE() in untrack_pfn() and track_pfn_copy(), not properly calling free_pfn_range(). In free_pfn_range(), we either wouldn\'t call memtype_free() or would call it with the wrong range, possibly leaking memory. To fix that, let\'s update follow_phys() to refuse returning anon folios, and fallback to using the stored PFN inside vma->vm_pgoff for COW mappings if we run into that. We will now properly handle untrack_pfn() with COW mappings, where we don\'t need the cachemode. We\'ll have to fail fork()->track_pfn_copy() if the first page was replaced by an anon folio, though: we\'d have to store the cachemode in the VMA to make this work, likely growing the VMA size. For now, lets keep it simple and let track_pfn_copy() just fail in that case: it would have failed in the past with swap/nonswap entries already, and it would have done the wrong thing with anon folios. Simple reproducer to trigger the WARN_ON_ONCE() in untrack_pfn(): <--- C reproducer ---> #include
Find out more about CVE-2024-35877 from the MITRE-CVE dictionary and NIST NVD
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Product Name | Status | Defect | Fixed | Downloads |
---|---|---|---|---|
Linux | ||||
Wind River Linux LTS 17 | Requires LTSS | -- | -- | -- |
Wind River Linux 8 | Requires LTSS | -- | -- | -- |
Wind River Linux 9 | Requires LTSS | -- | -- | -- |
Wind River Linux 7 | Requires LTSS | -- | -- | -- |
Wind River Linux LTS 21 | Investigate | -- | -- | -- |
Wind River Linux LTS 22 | Fixed |
LIN1022-8382 |
10.22.33.17 | -- |
Wind River Linux LTS 18 | Requires LTSS | -- | -- | -- |
Wind River Linux LTS 19 | Investigate | -- | -- | -- |
Wind River Linux CD release | N/A | -- | -- | -- |
Wind River Linux 6 | Requires LTSS | -- | -- | -- |
Wind River Linux LTS 23 | Fixed |
LIN1023-5655 |
10.23.30.11 | -- |
VxWorks | ||||
VxWorks 7 | Not Vulnerable | -- | -- | -- |
VxWorks 6.9 | Not Vulnerable | -- | -- | -- |
Helix Virtualization Platform Cert Edition | ||||
Helix Virtualization Platform Cert Edition | Not Vulnerable | -- | -- | -- |
Product Name | Status | Defect | Fixed | Downloads |
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