From df733ddc263dbe5f471e7c80c8b669532f56bf76 Mon Sep 17 00:00:00 2001 From: Matt Evans Date: Mon, 11 May 2026 07:46:42 -0700 Subject: [PATCH] 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: 89e1f7d4c66d8 ("vfio: Add PCI device driver") Signed-off-by: Matt Evans Link: https://lore.kernel.org/r/20260511144642.2926799-1-mattev@meta.com Signed-off-by: Alex Williamson --- include/linux/vfio_pci_core.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h index 2ebba746c18f..89165b769e5c 100644 --- a/include/linux/vfio_pci_core.h +++ b/include/linux/vfio_pci_core.h @@ -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)