Bug 2401416 (CVE-2025-39939) - CVE-2025-39939 kernel: iommu/s390: Fix memory corruption when using identity domain
Summary: CVE-2025-39939 kernel: iommu/s390: Fix memory corruption when using identity ...
Keywords:
Status: NEW
Alias: CVE-2025-39939
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-10-04 08:01 UTC by OSIDB Bzimport
Modified: 2025-10-06 18:36 UTC (History)
0 users

Fixed In Version:
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Description OSIDB Bzimport 2025-10-04 08:01:55 UTC
In the Linux kernel, the following vulnerability has been resolved:

iommu/s390: Fix memory corruption when using identity domain

zpci_get_iommu_ctrs() returns counter information to be reported as part
of device statistics; these counters are stored as part of the s390_domain.
The problem, however, is that the identity domain is not backed by an
s390_domain and so the conversion via to_s390_domain() yields a bad address
that is zero'd initially and read on-demand later via a sysfs read.
These counters aren't necessary for the identity domain; just return NULL
in this case.

This issue was discovered via KASAN with reports that look like:
BUG: KASAN: global-out-of-bounds in zpci_fmb_enable_device
when using the identity domain for a device on s390.


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