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

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Cc Paolo, Stefan, Xuan and linux-block.

On 10/19/23 17:52, Michael S. Tsirkin wrote:
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


--
zhenwei pi
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