Vulnerability CVE-2021-47035
Published: 2024-02-28

Description:
In the Linux kernel, the following vulnerability has been resolved:

iommu/vt-d: Remove WO permissions on second-level paging entries

When the first level page table is used for IOVA translation, it only
supports Read-Only and Read-Write permissions. The Write-Only permission
is not supported as the PRESENT bit (implying Read permission) should
always set. When using second level, we still give separate permissions
that allows WriteOnly which seems inconsistent and awkward. We want to
have consistent behavior. After moving to 1st level, we don't want things
to work sometimes, and break if we use 2nd level for the same mappings.
Hence remove this configuration.

 References:
https://git.kernel.org/stable/c/c848416cc05afc1589edba04fe00b85c2f797ee3
https://git.kernel.org/stable/c/89bd620798704a8805fc9db0d71d7f812cf5b3d2
https://git.kernel.org/stable/c/25faff78138933244c678c7fc78f7c0340fa04a0
https://git.kernel.org/stable/c/66c24699f266ff310381a9552d3576eea8ad6e20
https://git.kernel.org/stable/c/eea53c5816889ee8b64544fa2e9311a81184ff9c
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