[PATCH AUTOSEL 5.15 3/4] virtio-blk: fix implicit overflow on virtio_max_dma_size

[Sasha Levin]

From: zhenwei pi <pizhenwei@xxxxxxxxxxxxx>

[ Upstream commit fafb51a67fb883eb2dde352539df939a251851be ]

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>
Message-Id: <20230904061045.510460-1-pizhenwei@xxxxxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 d2ba849bb8d19..affeca0dbc7ea 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -743,6 +743,7 @@ 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",
@@ -844,7 +845,8 @@ static int virtblk_probe(struct virtio_device *vdev)
 	/* No real sector limit. */
 	blk_queue_max_hw_sectors(q, -1U);
 
-	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. */
-- 
2.42.0