Bug 2424929 (CVE-2023-54034)

Summary: CVE-2023-54034 kernel: Kernel (iommufd): Information Disclosure via uninitialized memory padding
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in the kernel. A local attacker could exploit this by triggering a missing zero initialization in the `iommufd` component when copying `vfio_iommu_type1_info` to user space. This could lead to the disclosure of sensitive information from uninitialized memory padding.
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Description OSIDB Bzimport 2025-12-24 12:01:25 UTC 
In the Linux kernel, the following vulnerability has been resolved:

iommufd: Make sure to zero vfio_iommu_type1_info before copying to user

Missed a zero initialization here. Most of the struct is filled with
a copy_from_user(), however minsz for that copy is smaller than the
actual struct by 8 bytes, thus we don't fill the padding.
Comment 1 Alexander B 2025-12-25 15:13:22 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025122438-CVE-2023-54034-3089@gregkh/T