vfio/pci: Make VFIO_PCI_OFFSET_TO_INDEX() return unsigned

VFIO_PCI_OFFSET_TO_INDEX() is used in several places with a signed
parameter (e.g. loff_t).  Because it makes no sense for a BAR/resource
index to be negative, enforce this in the macro.

This fixes at least one current issue, where vfio_pci_ioeventfd() uses
this macro with an unvalidated signed loff_t returned into a signed
type, leading to a possible negative array access.  This instance does
test against an out-of-bounds positive value, so treating the index as
unsigned fixes this issue.

Fixes: 89e1f7d4c6 ("vfio: Add PCI device driver")
Signed-off-by: Matt Evans <mattev@meta.com>
Link: https://lore.kernel.org/r/20260511144642.2926799-1-mattev@meta.com
Signed-off-by: Alex Williamson <alex@shazbot.org>
This commit is contained in:
Matt Evans
2026-05-11 07:46:42 -07:00
committed by Alex Williamson
parent c64a647c84
commit df733ddc26

View File

@@ -21,7 +21,7 @@
#define VFIO_PCI_CORE_H
#define VFIO_PCI_OFFSET_SHIFT 40
#define VFIO_PCI_OFFSET_TO_INDEX(off) (off >> VFIO_PCI_OFFSET_SHIFT)
#define VFIO_PCI_OFFSET_TO_INDEX(off) ((u64)(off) >> VFIO_PCI_OFFSET_SHIFT)
#define VFIO_PCI_INDEX_TO_OFFSET(index) ((u64)(index) << VFIO_PCI_OFFSET_SHIFT)
#define VFIO_PCI_OFFSET_MASK (((u64)(1) << VFIO_PCI_OFFSET_SHIFT) - 1)