Description
In 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]
Metrics
No CVSS score has been published yet.
Affected software
Source: the vendor's advisory (CNA). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux | >= eb627e17727ebeede70697ae1798688b0d328b54, < 3556caa31a2bfbc22c11b812fd4ed8851c2d7bff; >= eb627e17727ebeede70697ae1798688b0d328b54, < cd07aef510ac6a2873e01f9ddddc5492490b0067; >= eb627e17727ebeede70697ae1798688b0d328b54, < 747b9bbbbdfdee51aee2456388f9b94b5086de4d |
| Linux | Linux | 5.4 |
References
Timeline
- Published
- Sep 17, 2026
- Last modified
- Oct 19, 2026
- NVD status
- Received