Commit df733ddc authored by Matt Evans's avatar Matt Evans Committed by Alex Williamson
Browse files

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: 89e1f7d4 ("vfio: Add PCI device driver")
Signed-off-by: default avatarMatt Evans <mattev@meta.com>
Link: https://lore.kernel.org/r/20260511144642.2926799-1-mattev@meta.com


Signed-off-by: default avatarAlex Williamson <alex@shazbot.org>
parent c64a647c

include/linux/vfio_pci_core.h

+1 −1
Original line number Diff line number Diff line
@@ -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)