Linux Kernel up to 6.9.4 hugetlb __unmap_hugepage_range allocation of resources

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.9.4 and classified as problematic. This vulnerability affects the function __unmap_hugepage_range of the component hugetlb. The manipulation results in allocation of resources. This vulnerability is reported as CVE-2024-39477. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Linux Kernel up to 6.9.4. Affected is the function __unmap_hugepage_range of the component hugetlb. The manipulation with an unknown input leads to a allocation of resources vulnerability. CWE is classifying the issue as CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. This is going to have an impact on availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: do not call vma_add_reservation upon ENOMEM sysbot reported a splat [1] on __unmap_hugepage_range(). This is because vma_needs_reservation() can return -ENOMEM if allocate_file_region_entries() fails to allocate the file_region struct for the reservation. Check for that and do not call vma_add_reservation() if that is the case, otherwise region_abort() and region_del() will see that we do not have any file_regions. If we detect that vma_needs_reservation() returned -ENOMEM, we clear the hugetlb_restore_reserve flag as if this reservation was still consumed, so free_huge_folio() will not increment the resv count. [1] https://lore.kernel.org/linux-mm/[email protected]/T/#ma5983bc1ab18a54910da83416b3f89f3c7ee43aa

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2024-39477 since 06/25/2024. There are known technical details, but no exploit is available.

Upgrading to version 6.9.5 eliminates this vulnerability. Applying the patch aa998f9dcb34/8daf9c702ee7 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.9.0
• 6.9.1
• 6.9.2
• 6.9.3
• 6.9.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

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