ata: ahci: fail probe if BAR too small for claimed ports

In the Linux kernel, the following vulnerability has been resolved: ata: ahci: fail probe if BAR too small for claimed ports When an AHCI controller is disabled in BIOS, its HOST_CAP register may contain a bogus value, e.g. 0xFFFFFFFF. Since CAP.NP (Number of Ports) is a zeroes based 5-bit register field, a value of 0x1f means 32 ports. If CAP.NP claims more ports than can physically fit within the mapped BAR region, accessing port registers beyond the BAR boundary causes a kernel panic. Add validation in ahci_init_one() to check that the BAR size is sufficient for the number of ports claimed in CAP.NP. The check calculates the required MMIO size as: required_size = 0x100 (global registers) + max_ports * 0x80 If required_size exceeds the actual BAR size, the probe fails with -ENODEV, preventing the panic and providing a clear error message. [cassel: commit log]

Source published

24 Sep 2026 16:03:54 UTC

Source modified

3 Oct 2026 10:58:26 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.