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

Summary

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]

Timeline

1. Sep 24, 2026, 4:03 PM UTCCVE published
2. Oct 3, 2026, 10:58 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 533a08ea11217100cec7a0ed903cb9b9c892d6f1; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in c717b20100ef8cd06b5237af70ea2cb692e058ce; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in ff0ab535f8febbd32afa5832f8d2d9b06a8d5060; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 6d29b91164424256a759ddabc8f2de1ae09bd3f1; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in df262c828b616450eb351349e91c63447551bd01; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in f2e291043c37a896d7f9797e25a356dceb030177; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in c4086c6e1af757e1ff26fa2d2926b3ec0195de79

• Linux Linux

  2.6.12

• KernelLinux

  From 2.6.12 · fixed in 5.10.271; From 5.11.0 · fixed in 5.15.222; From 5.16.0 · fixed in 6.1.189; From 6.2.0 · fixed in 6.6.158; From 6.7.0 · fixed in 6.12.111; From 6.13.0 · fixed in 6.18.53

References 7