Time-of-check Time-of-use (TOCTOU) Affecting kernel-rt-debug package, versions *
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Test your applications- Snyk ID SNYK-CENTOS7-KERNELRTDEBUG-7195196
- published 3 Jun 2024
- disclosed 30 May 2024
Introduced: 30 May 2024
CVE-2024-36943 Open this link in a new tabHow to fix?
There is no fixed version for Centos:7 kernel-rt-debug.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-rt-debug package and not the kernel-rt-debug package as distributed by Centos.
See How to fix? for Centos:7 relevant fixed versions and status.
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);