Re: PING: [PATCH] virtio-blk: fix implicit overflow on virtio_max_dma_size

[Michael S. Tsirkin]

On Thu, Oct 19, 2023 at 05:43:55PM +0800, zhenwei pi wrote:
> Hi Michael,
> 
> This seems to have been ignored as you suggested.
> 
> LINK: https://www.spinics.net/lists/linux-virtualization/msg63015.html

Pls Cc more widely then:

Paolo Bonzini <pbonzini@xxxxxxxxxx> (reviewer:VIRTIO BLOCK AND SCSI DRIVERS)
Stefan Hajnoczi <stefanha@xxxxxxxxxx> (reviewer:VIRTIO BLOCK AND SCSI DRIVERS)
Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> (reviewer:VIRTIO CORE AND NET DRIVERS)
Jens Axboe <axboe@xxxxxxxxx> (maintainer:BLOCK LAYER)
linux-block@xxxxxxxxxxxxxxx (open list:BLOCK LAYER)

would all be good people to ask to review this.


> On 9/4/23 14:10, zhenwei pi wrote:
> > The following codes have an implicit conversion from size_t to u32:
> > (u32)max_size = (size_t)virtio_max_dma_size(vdev);
> > 
> > This may lead overflow, Ex (size_t)4G -> (u32)0. Once
> > virtio_max_dma_size() has a larger size than U32_MAX, use U32_MAX
> > instead.
> > 
> > Signed-off-by: zhenwei pi <pizhenwei@xxxxxxxxxxxxx>
> > ---
> >   drivers/block/virtio_blk.c | 4 +++-
> >   1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> > index 1fe011676d07..4a4b9bad551e 100644
> > --- a/drivers/block/virtio_blk.c
> > +++ b/drivers/block/virtio_blk.c
> > @@ -1313,6 +1313,7 @@ static int virtblk_probe(struct virtio_device *vdev)
> >   	u16 min_io_size;
> >   	u8 physical_block_exp, alignment_offset;
> >   	unsigned int queue_depth;
> > +	size_t max_dma_size;
> >   	if (!vdev->config->get) {
> >   		dev_err(&vdev->dev, "%s failure: config access disabled\n",
> > @@ -1411,7 +1412,8 @@ static int virtblk_probe(struct virtio_device *vdev)
> >   	/* No real sector limit. */
> >   	blk_queue_max_hw_sectors(q, UINT_MAX);
> > -	max_size = virtio_max_dma_size(vdev);
> > +	max_dma_size = virtio_max_dma_size(vdev);
> > +	max_size = max_dma_size > U32_MAX ? U32_MAX : max_dma_size;
> >   	/* Host can optionally specify maximum segment size and number of
> >   	 * segments. */
> 
> -- 
> zhenwei pi