[2/2] vfio/fsl-mc: prevent underflow in vfio_fsl_mc_mmap()
diff mbox series

Message ID 20201023112947.GF282278@mwanda
State Accepted
Commit 69848cd6f0c1fb4f82ab255b730343a215ded013
Headers show
Series
  • [1/2] vfio/fsl-mc: return -EFAULT if copy_to_user() fails
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Commit Message

Dan Carpenter Oct. 23, 2020, 11:29 a.m. UTC
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 <dan.carpenter@oracle.com>
---
 drivers/vfio/fsl-mc/vfio_fsl_mc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Alex Williamson Nov. 2, 2020, 9:45 p.m. UTC | #1
Hi Diana, same for this one.  Thanks,

Alex

On Fri, 23 Oct 2020 14:29:47 +0300
Dan Carpenter <dan.carpenter@oracle.com> wrote:

> 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 <dan.carpenter@oracle.com>
> ---
>  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);
>
Diana Craciun OSS Nov. 3, 2020, 12:03 p.m. UTC | #2
Acked-by: Diana Craciun <diana.craciun@oss.nxp.com>

On 10/23/2020 2:29 PM, Dan Carpenter wrote:
> 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 <dan.carpenter@oracle.com>
> ---
>   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);
>   
>

Patch
diff mbox series

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);