uvesafb/connector: Disallow unpliviged users to send netlink packets

(cherry picked from commit 30efa3f76813b17445bc5a2e443ae9731518566b)
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/video/uvesafb.c

@@ -72,6 +72,9 @@ static void uvesafb_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *ns
 	struct uvesafb_task *utask;
 	struct uvesafb_ktask *task;
 
+	if (!cap_raised(nsp->eff_cap, CAP_SYS_ADMIN))
+		return;
+
 	if (msg->seq >= UVESAFB_TASKS_MAX)
 		return;