static int vop_virtio_copy_from_user(struct vop_vdev *vdev, void __user *ubuf,
				     size_t len, u64 daddr, size_t dlen,
				     int vr_idx)
{
	struct vop_device *vpdev = vdev->vpdev;
	void __iomem *dbuf = vpdev->hw_ops->ioremap(vpdev, daddr, len);
	struct vop_vringh *vvr = &vdev->vvr[vr_idx];
	struct vop_info *vi = dev_get_drvdata(&vdev->vpdev->dev);
	size_t dma_alignment = 1 << vi->dma_ch->device->copy_align;
	bool x200 = is_dma_copy_aligned(vi->dma_ch->device, 1, 1, 1);
	size_t partlen;
	bool dma = VOP_USE_DMA;
	int err = 0;

	if (daddr & (dma_alignment - 1)) {
		vdev->tx_dst_unaligned += len;
		dma = false;
	} else if (ALIGN(len, dma_alignment) > dlen) {
		vdev->tx_len_unaligned += len;
		dma = false;
	}

	if (!dma)
		goto memcpy;

	/*
	 * X100 uses DMA addresses as seen by the card so adding
	 * the aperture base is not required for DMA. However x200
	 * requires DMA addresses to be an offset into the bar so
	 * add the aperture base for x200.
	 */
	if (x200)
		daddr += vpdev->aper->pa;
	while (len) {
		partlen = min_t(size_t, len, VOP_INT_DMA_BUF_SIZE);

		if (copy_from_user(vvr->buf, ubuf, partlen)) {
			err = -EFAULT;
			dev_err(vop_dev(vdev), "%s %d err %d\n",
				__func__, __LINE__, err);
			goto err;
		}
		err = vop_sync_dma(vdev, daddr, vvr->buf_da,
				   ALIGN(partlen, dma_alignment));
		if (err) {
			dev_err(vop_dev(vdev), "%s %d err %d\n",
				__func__, __LINE__, err);
			goto err;
		}
		daddr += partlen;
		ubuf += partlen;
		dbuf += partlen;
		vdev->out_bytes_dma += partlen;
		vdev->out_bytes += partlen;
		len -= partlen;
	}
memcpy:
	/*
	 * We are copying to IO below and should ideally use something
	 * like copy_from_user_toio(..) if it existed.
	 */
	if (copy_from_user((void __force *)dbuf, ubuf, len)) {
		err = -EFAULT;
		dev_err(vop_dev(vdev), "%s %d err %d\n",
			__func__, __LINE__, err);
		goto err;
	}
	vdev->out_bytes += len;
	err = 0;
err:
	vpdev->hw_ops->iounmap(vpdev, dbuf);
	dev_dbg(vop_dev(vdev),
		"%s: ubuf %p dbuf %p len 0x%lx vr_idx 0x%x\n",
		__func__, ubuf, dbuf, len, vr_idx);
	return err;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.