From 69848cd6f0c1fb4f82ab255b730343a215ded013 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 23 Oct 2020 14:29:47 +0300 Subject: [PATCH] vfio/fsl-mc: prevent underflow in vfio_fsl_mc_mmap() My static analsysis tool complains that the "index" can be negative. There are some checks in do_mmap() which try to prevent underflows but I don't know if they are sufficient for this situation. Either way, making "index" unsigned is harmless so let's do it just to be safe. Fixes: 67247289688d ("vfio/fsl-mc: Allow userspace to MMAP fsl-mc device MMIO regions") Signed-off-by: Dan Carpenter Acked-by: Diana Craciun Signed-off-by: Alex Williamson --- drivers/vfio/fsl-mc/vfio_fsl_mc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc.c b/drivers/vfio/fsl-mc/vfio_fsl_mc.c index 21f22e3da11f..f27e25112c40 100644 --- a/drivers/vfio/fsl-mc/vfio_fsl_mc.c +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc.c @@ -472,7 +472,7 @@ static int vfio_fsl_mc_mmap(void *device_data, struct vm_area_struct *vma) { struct vfio_fsl_mc_device *vdev = device_data; struct fsl_mc_device *mc_dev = vdev->mc_dev; - int index; + unsigned int index; index = vma->vm_pgoff >> (VFIO_FSL_MC_OFFSET_SHIFT - PAGE_SHIFT);