PCI/sysfs: Add lockdown checks to legacy I/O and memory handlers

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Summary

CVECVE-2026-90315
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-17 17:17:29 UTC
Updated2026-09-17 17:17:29 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: PCI/sysfs: Add lockdown checks to legacy I/O and memory handlers Currently, the legacy I/O and memory sysfs handlers do not check security_locked_down(LOCKDOWN_PCI_ACCESS), leaving the legacy_io and legacy_mem files unprotected when the kernel is locked down. Commit eb627e17727e ("PCI: Lock down BAR access when the kernel is locked down") added the check to pci_write_config(), pci_mmap_resource(), and pci_write_resource_io() to prevent userspace from programming DMA-capable hardware that could be used to modify kernel code, but did not cover the legacy handlers. As a result, root can still write arbitrary I/O ports and map the legacy I/O and memory spaces while the kernel is locked down, which is the same capability the lockdown is meant to remove. Add the same check to pci_write_legacy_io(), pci_mmap_legacy_mem(), and pci_mmap_legacy_io(). These generic handlers cover both architectures that define HAVE_PCI_LEGACY (such as Alpha and PowerPC). [bhelgaas: add Link]

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected eb627e17727ebeede70697ae1798688b0d328b54 cd07aef510ac6a2873e01f9ddddc5492490b0067 git Not specified
CNA Linux Linux affected eb627e17727ebeede70697ae1798688b0d328b54 747b9bbbbdfdee51aee2456388f9b94b5086de4d git Not specified
CNA Linux Linux affected 5.4 Not specified
CNA Linux Linux unaffected 5.4 semver Not specified
CNA Linux Linux unaffected 7.2.6 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/cd07aef510ac6a2873e01f9ddddc5492490b0067 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/747b9bbbbdfdee51aee2456388f9b94b5086de4d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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