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CVE-2026-97533: Linux

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    Оригинално описание

    In the Linux kernel, the following vulnerability has been resolved: x86/mm/pat: Acquire init_mm read lock on attribute changes to avoid UAF A previous commit protected against races between ptdump and CPA collapse, however one still exists between attribute changes and collapse as reported by Denis V. Lunev (linked). When an attribute change arises, a lockless page table walker obtains a PTE entry, which is later written to via set_pte_atomic(): ... -> change_page_attr_set_clr() -> __change_page_attr_set_clr() -> __change_page_attr() -> _lookup_address_cpa() -> lookup_address_in_pgd_attr() -> [ lockless page table walker ] -> set_pte_atomic() There is nothing preventing a concurrent CPA collapse which can free the PTE that was retrieved here, resulting in a use-after-free. With the mmap write lock taken on init_mm over CPA collapse, resolve this race by acquiring an mmap read lock on init_mm over __change_page_attr_set_clr(). This locks across the whole operation over which the walk and the PTE entry write occurs, solving the race. It is safe to do this here, as no spinlocks are held upon entry to __change_page_attr_set_clr(). However, the lock must not be held over an allocation, as allocation can trigger reclaim and shrinkers may call into CPA recursively, making deadlocks possible (init_mm -> ... -> fs_reclaim -> init_mm). A page table is allocated when a huge page needs to be split: -> change_page_attr_set_clr() -> __change_page_attr_set_clr() -> __change_page_attr() -> split_large_page() [ pagetable_alloc() ] -> __split_large_page() Avoid deadlocks by dropping the mmap lock across pagetable_alloc() in split_large_page() and track whether this is needed by adding a new 'init_mm_read_locked' flag to struct cpa_data. This is safe as __split_large_page() (called with locks re-established) revalidates that the page table entry is the same as it was prior to the locks being dropped and __change_page_attr() repeats the entire page

    Засегнати продукти

    • Linux Linux: 41d88484c71cd4f659348da41b7b5b3dbd3be1f6 преди e21a9ea81426a85fdb0cdcfcc99d5d9c16b402ab; 41d88484c71cd4f659348da41b7b5b3dbd3be1f6 преди cc73b2043d106b467accd38e9b1fc09e0607c056; 41d88484c71cd4f659348da41b7b5b3dbd3be1f6 преди d5d8b8662e6e5a565b47a0388640e88402f23274
    • Linux Linux: 6.15; преди 6.15; 6.18.53 до 6.18.*; 7.2.7 до 7.2.*; от 7.3 нататък

    История

    • 25 септември 2026 Публикувано

    Други уязвимости в Linux Linux

    Първоизточници

    CVE-2026-97533: Linux | freedomonline.bg