qeth: avoid buffer overflow in snmp ioctl

Check user-defined length in snmp ioctl request and allow request
only if it fits into a qeth command buffer.

Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Reviewed-by: Heiko Carstens <heicars2@linux.vnet.ibm.com>
Reported-by: Nico Golde <nico@ngolde.de>
Reported-by: Fabian Yamaguchi <fabs@goesec.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
static void qeth_core_sl_print(struct seq_file *m, struct service_level *slr)
{
	struct qeth_card *card = container_of(slr, struct qeth_card,
					qeth_service_level);
	if (card->info.mcl_level[0])
		seq_printf(m, "qeth: %s firmware level %s\n",
			CARD_BUS_ID(card), card->info.mcl_level);
}

static void qeth_core_sl_print(struct seq_file *m, struct service_level *slr)
{
	struct qeth_card *card = container_of(slr, struct qeth_card,
					qeth_service_level);
	if (card->info.mcl_level[0])
		seq_printf(m, "qeth: %s firmware level %s\n",
			CARD_BUS_ID(card), card->info.mcl_level);
}
