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Commit 57d547a4 authored by Jose Abreu's avatar Jose Abreu Committed by Greg Kroah-Hartman
Browse files

net: stmmac: Do not accept invalid MTU values 



[ Upstream commit eaf4fac478077d4ed57cbca2c044c4b58a96bd98 ]

The maximum MTU value is determined by the maximum size of TX FIFO so
that a full packet can fit in the FIFO. Add a check for this in the MTU
change callback.

Also check if provided and rounded MTU does not passes the maximum limit
of 16K.

Changes from v2:
- Align MTU before checking if its valid

Fixes: 7ac6653a ("stmmac: Move the STMicroelectronics driver")
Signed-off-by: default avatarJose Abreu <Jose.Abreu@synopsys.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 77de8ee6

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

+12 −0
Original line number Diff line number Diff line
@@ -3604,12 +3604,24 @@ static void stmmac_set_rx_mode(struct net_device *dev) 
static int stmmac_change_mtu(struct net_device *dev, int new_mtu)

{

	struct stmmac_priv *priv = netdev_priv(dev);

	int txfifosz = priv->plat->tx_fifo_size;



	if (txfifosz == 0)

		txfifosz = priv->dma_cap.tx_fifo_size;



	txfifosz /= priv->plat->tx_queues_to_use;



	if (netif_running(dev)) {

		netdev_err(priv->dev, "must be stopped to change its MTU\n");

		return -EBUSY;

	}



	new_mtu = STMMAC_ALIGN(new_mtu);



	/* If condition true, FIFO is too small or MTU too large */

	if ((txfifosz < new_mtu) || (new_mtu > BUF_SIZE_16KiB))

		return -EINVAL;



	dev->mtu = new_mtu;



	netdev_update_features(dev);