PCI: dwc: ep: Prevent changing BAR size/flags in pci_epc_set_bar()

Summary

In the Linux kernel, the following vulnerability has been resolved: PCI: dwc: ep: Prevent changing BAR size/flags in pci_epc_set_bar() In commit 4284c88fff0e ("PCI: designware-ep: Allow pci_epc_set_bar() update inbound map address") set_bar() was modified to support dynamically changing the backing physical address of a BAR that was already configured. This means that set_bar() can be called twice, without ever calling clear_bar() (as calling clear_bar() would clear the BAR's PCI address assigned by the host). This can only be done if the new BAR size/flags does not differ from the existing BAR configuration. Add these missing checks. If we allow set_bar() to set e.g. a new BAR size that differs from the existing BAR size, the new address translation range will be smaller than the BAR size already determined by the host, which would mean that a read past the new BAR size would pass the iATU untranslated, which could allow the host to read memory not belonging to the new struct pci_epf_bar. While at it, add comments which clarifies the support for dynamically changing the physical address of a BAR. (Which was also missing.)

Timeline

1. Feb 27, 2025, 2:12 AM UTCCVE published
2. Oct 21, 2026, 12:35 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 4284c88fff0efc4e418abb53d78e02dc4f099d6c · fixed in 01aaa7935af3050fd1e1e7de50001247c75baeab; From 4284c88fff0efc4e418abb53d78e02dc4f099d6c · fixed in b5cacfd067060c75088363ed3e19779078be2755; From 4284c88fff0efc4e418abb53d78e02dc4f099d6c · fixed in 3229c15d6267de8e704b4085df8a82a5af2d63eb; From 4284c88fff0efc4e418abb53d78e02dc4f099d6c · fixed in 3708acbd5f169ebafe1faa519cb28adc56295546

• Linux Linux

  6.0

• KernelLinux

  From 6.0.0 · fixed in 6.6.160; From 6.7.0 · fixed in 6.12.14; From 6.13.0 · fixed in 6.13.3

References 4