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Vulnerability CVE-2024-36943
Published: 2024-05-30
| Description: |
In the Linux kernel, the following vulnerability has been resolved:
fs/proc/task_mmu: fix loss of young/dirty bits during pagemap scan
make_uffd_wp_pte() was previously doing:
pte = ptep_get(ptep);
ptep_modify_prot_start(ptep);
pte = pte_mkuffd_wp(pte);
ptep_modify_prot_commit(ptep, pte);
But if another thread accessed or dirtied the pte between the first 2
calls, this could lead to loss of that information. Since
ptep_modify_prot_start() gets and clears atomically, the following is the
correct pattern and prevents any possible race. Any access after the
first call would see an invalid pte and cause a fault:
pte = ptep_modify_prot_start(ptep);
pte = pte_mkuffd_wp(pte);
ptep_modify_prot_commit(ptep, pte); |
References: |
https://git.kernel.org/stable/c/74b3d66f91d9f539f99faad74d796fa9a389a015
https://git.kernel.org/stable/c/c70dce4982ce1718bf978a35f8e26160b82081f4
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