static void uvesafb_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
{
	struct uvesafb_task *utask;
	struct uvesafb_ktask *task;

	if (!capable(CAP_SYS_ADMIN))
		return;

	if (msg->seq >= UVESAFB_TASKS_MAX)
		return;

	mutex_lock(&uvfb_lock);
	task = uvfb_tasks[msg->seq];

	if (!task || msg->ack != task->ack) {
		mutex_unlock(&uvfb_lock);
		return;
	}

	utask = (struct uvesafb_task *)msg->data;

	/* Sanity checks for the buffer length. */
	if (task->t.buf_len < utask->buf_len ||
	    utask->buf_len > msg->len - sizeof(*utask)) {
		mutex_unlock(&uvfb_lock);
		return;
	}

	uvfb_tasks[msg->seq] = NULL;
	mutex_unlock(&uvfb_lock);

	memcpy(&task->t, utask, sizeof(*utask));

	if (task->t.buf_len && task->buf)
		memcpy(task->buf, utask + 1, task->t.buf_len);

	complete(task->done);
	return;
}

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.