public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
* [patch 1/3 v2] vfio: signedness bug in vfio_config_do_rw()
       [not found] <4FEC0480.7010508@bfs.de>
@ 2012-06-28  8:07 ` Dan Carpenter
  2012-06-28 22:24   ` Alex Williamson
  0 siblings, 1 reply; 2+ messages in thread
From: Dan Carpenter @ 2012-06-28  8:07 UTC (permalink / raw)
  To: Alex Williamson; +Cc: kvm, linux-kernel, kernel-janitors, walter harms

The "count" variable needs to be signed here because we use it to store
negative error codes.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2: Just declare count as signed.

diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index a4f7321..2e00aa8 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -1419,7 +1419,7 @@ void vfio_config_free(struct vfio_pci_device *vdev)
 }
 
 static ssize_t vfio_config_do_rw(struct vfio_pci_device *vdev, char __user *buf,
-				 size_t count, loff_t *ppos, bool iswrite)
+				 ssize_t count, loff_t *ppos, bool iswrite)
 {
 	struct pci_dev *pdev = vdev->pdev;
 	struct perm_bits *perm;

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [patch 1/3 v2] vfio: signedness bug in vfio_config_do_rw()
  2012-06-28  8:07 ` [patch 1/3 v2] vfio: signedness bug in vfio_config_do_rw() Dan Carpenter
@ 2012-06-28 22:24   ` Alex Williamson
  0 siblings, 0 replies; 2+ messages in thread
From: Alex Williamson @ 2012-06-28 22:24 UTC (permalink / raw)
  To: Dan Carpenter; +Cc: kvm, linux-kernel, kernel-janitors, walter harms

On Thu, 2012-06-28 at 11:07 +0300, Dan Carpenter wrote:
> The "count" variable needs to be signed here because we use it to store
> negative error codes.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> v2: Just declare count as signed.
> 
> diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
> index a4f7321..2e00aa8 100644
> --- a/drivers/vfio/pci/vfio_pci_config.c
> +++ b/drivers/vfio/pci/vfio_pci_config.c
> @@ -1419,7 +1419,7 @@ void vfio_config_free(struct vfio_pci_device *vdev)
>  }
>  
>  static ssize_t vfio_config_do_rw(struct vfio_pci_device *vdev, char __user *buf,
> -				 size_t count, loff_t *ppos, bool iswrite)
> +				 ssize_t count, loff_t *ppos, bool iswrite)
>  {
>  	struct pci_dev *pdev = vdev->pdev;
>  	struct perm_bits *perm;

signed doesn't seem right for count since just below this chunk we do:

        if (*ppos < 0 || *ppos + count > pdev->cfg_size)
                return -EFAULT;

So then we have to start testing for negative count.  I've added a
ssize_t variable for return that should clear things up.  Thanks for the
report!

Alex


^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2012-06-28 22:24 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
     [not found] <4FEC0480.7010508@bfs.de>
2012-06-28  8:07 ` [patch 1/3 v2] vfio: signedness bug in vfio_config_do_rw() Dan Carpenter
2012-06-28 22:24   ` Alex Williamson

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox