CVE-2026-89731cxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER register read

Official description

In the Linux kernel, the following vulnerability has been resolved: cxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER register read cxl_rch_get_aer_info() copies the RCH Downstream Port AER capability from the RCRB MMIO block using a readl() loop bounded by sizeof(struct aer_capability_regs). This struct is a software layout and its embedded struct pcie_tlp_log is larger than the on-wire AER capability. As a result the loop reads past the mapped AER register block. The over-read also populates the software-only tail fields including header_log.header_len. An out-of-range header_len passed to pcie_print_tlp_log() can then loop past the header log buffer and cause a second out-of-bounds read. The read was correct when introduced, but struct pcie_tlp_log has since grown (Header Log and TLP Prefix Log sizes, header_len and flit fields), so sizeof(struct aer_capability_regs) no longer matches the physical AER capability. Bound the read to the physical AER registers, header through the 16 byte Header Log. Zero the destination first so the software-only fields are deterministic.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/7f5a2a330dde8e8aa2dd80e1f3e05b6ada049607
• https://git.kernel.org/stable/c/8bd3523df1319edc61cd391e695c84a4618516df
• https://git.kernel.org/stable/c/8e3d9dbb25d3ddbe72b4542ec4f7c4e622fe0ced
• https://git.kernel.org/stable/c/29458e62d0829cbc99435f3e44fd560f9bbf1da7