CVE Catalog

CVE-2017-1000405

High
Published: Translated: NVD NIST

Summary

Linux Kernel versions 2.6.38 through 4.14 have a problematic use of pmd_mkdirty() in touch_pmd(), which may lead to overwriting read-only huge pages. Although not as severe as the original 'Dirty cow' vulnerability, it allows for overwriting pages like zero huge page.

Risk Assessment

Organizations may be at risk of data integrity loss due to the ability to overwrite memory data. While not as critical as other vulnerabilities, it can impact the security of applications using huge pages.

Recommendation

It is recommended to update the Linux kernel to a version that does not contain this vulnerability. Additionally, monitor applications using huge pages for potential issues.

Other vulnerabilities in Linux Kernel

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Original NVD description (English source)

The Linux Kernel versions 2.6.38 through 4.14 have a problematic use of pmd_mkdirty() in the touch_pmd() function inside the THP implementation. touch_pmd() can be reached by get_user_pages(). In such case, the pmd will become dirty. This scenario breaks the new can_follow_write_pmd()'s logic - pmd can become dirty without going through a COW cycle. This bug is not as severe as the original "Dirty cow" because an ext4 file (or any other regular file) cannot be mapped using THP. Nevertheless, it does allow us to overwrite read-only huge pages. For example, the zero huge page and sealed shmem files can be overwritten (since their mapping can be populated using THP). Note that after the first write page-fault to the zero page, it will be replaced with a new fresh (and zeroed) thp.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS