V4L/DVB (3388): Ignore DiSEqC messages > 6 and < 3

Ignore invalid messages on cx24110 frontend.
Thanks to Edgar Toernig

Signed-off-by: Manu Abraham <manu@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/dvb/frontends/cx24110.c

@@ -418,6 +418,9 @@ static int cx24110_send_diseqc_msg(struct dvb_frontend* fe,
 	struct cx24110_state *state = fe->demodulator_priv;
 	unsigned long timeout;
 
+	if (cmd->msg_len < 3 || cmd->msg_len > 6)
+		return -EINVAL;  /* not implemented */
+
 	for (i = 0; i < cmd->msg_len; i++)
 		cx24110_writereg(state, 0x79 + i, cmd->msg[i]);