Re: [PATCH v2] scsi: virtio_scsi: Fix poential NULL pointer dereference in virtscsi_rescan_hotunplug

2023-02-14 Thread Stefan Hajnoczi
On Mon, Feb 13, 2023 at 07:09:50AM -0500, Michael S. Tsirkin wrote:
> On Thu, Feb 02, 2023 at 02:41:24PM +0800, Zheng Wang wrote:
> > There is no check about the return value of kmalloc in
> > virtscsi_rescan_hotunplug. Add the check to avoid use
> > of null pointer 'inq_result' in case of the failure
> > of kmalloc.
> > 
> > Signed-off-by: Zheng Wang 
> > ---
> 
> I fixed a typo in subject and tweaked the patch a bit

Thanks for picking this patch up.
https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git/commit/?h=linux-next=4a8fc6e3ac68ce4c355d1f4473ef1d8468b23bdc

Stefan


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Re: [PATCH v2] scsi: virtio_scsi: Fix poential NULL pointer dereference in virtscsi_rescan_hotunplug

2023-02-13 Thread Michael S. Tsirkin
On Thu, Feb 02, 2023 at 02:41:24PM +0800, Zheng Wang wrote:
> There is no check about the return value of kmalloc in
> virtscsi_rescan_hotunplug. Add the check to avoid use
> of null pointer 'inq_result' in case of the failure
> of kmalloc.
> 
> Signed-off-by: Zheng Wang 
> ---

I fixed a typo in subject and tweaked the patch a bit

> v2:
> - add kfree to avoid memory leak
> ---
>  drivers/scsi/virtio_scsi.c | 13 +++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
> index d07d24c06b54..a66d8815d738 100644
> --- a/drivers/scsi/virtio_scsi.c
> +++ b/drivers/scsi/virtio_scsi.c
> @@ -330,7 +330,7 @@ static void virtscsi_handle_param_change(struct 
> virtio_scsi *vscsi,
>   scsi_device_put(sdev);
>  }
>  
> -static void virtscsi_rescan_hotunplug(struct virtio_scsi *vscsi)
> +static int virtscsi_rescan_hotunplug(struct virtio_scsi *vscsi)
>  {
>   struct scsi_device *sdev;
>   struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
> @@ -338,6 +338,11 @@ static void virtscsi_rescan_hotunplug(struct virtio_scsi 
> *vscsi)
>   int result, inquiry_len, inq_result_len = 256;
>   char *inq_result = kmalloc(inq_result_len, GFP_KERNEL);
>  
> + if (!inq_result) {
> + kfree(inq_result);
> + return -ENOMEM;
> + }
> +
>   shost_for_each_device(sdev, shost) {
>   inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
>  
> @@ -366,6 +371,7 @@ static void virtscsi_rescan_hotunplug(struct virtio_scsi 
> *vscsi)
>   }
>  
>   kfree(inq_result);
> + return 0;
>  }
>  
>  static void virtscsi_handle_event(struct work_struct *work)
> @@ -374,12 +380,15 @@ static void virtscsi_handle_event(struct work_struct 
> *work)
>   container_of(work, struct virtio_scsi_event_node, work);
>   struct virtio_scsi *vscsi = event_node->vscsi;
>   struct virtio_scsi_event *event = _node->event;
> + int ret = 0;
>

dropped = 0 here
  
>   if (event->event &
>   cpu_to_virtio32(vscsi->vdev, VIRTIO_SCSI_T_EVENTS_MISSED)) {

and moved declaration here.

>   event->event &= ~cpu_to_virtio32(vscsi->vdev,
>  VIRTIO_SCSI_T_EVENTS_MISSED);
> - virtscsi_rescan_hotunplug(vscsi);
> + ret = virtscsi_rescan_hotunplug(vscsi);
> + if (ret)
> + return;
>   scsi_scan_host(virtio_scsi_host(vscsi->vdev));
>   }
>  
> -- 
> 2.25.1
> 
> 

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