davinci_emac: fix kernel oops when changing MAC address while interface is down

Check that network interface is running before changing its MAC address.
Otherwise, rxch is accessed when it's NULL - causing a kernel oops.
Moreover, check that the new MAC address is valid.

Signed-off-by: Pablo Bitton <pablo.bitton@gmail.com>
Signed-off-by: Chaithrika U S <chaithrika@ti.com>
Tested-by: Chaithrika U S <chaithrika@ti.com>
[tested on DM6467 EVM]
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/net/davinci_emac.c b/drivers/net/davinci_emac.c
index 2df8fb0af701..12fd446f9895 100644
--- a/drivers/net/davinci_emac.c
+++ b/drivers/net/davinci_emac.c
@@ -1820,11 +1820,19 @@ static int emac_dev_setmac_addr(struct net_device *ndev, void *addr)
         struct device *emac_dev = &priv->ndev->dev;
         struct sockaddr *sa = addr;
 
+        if (!is_valid_ether_addr(sa->sa_data))
+                return -EINVAL;
+
         /* Store mac addr in priv and rx channel and set it in EMAC hw */
         memcpy(priv->mac_addr, sa->sa_data, ndev->addr_len);
-        memcpy(rxch->mac_addr, sa->sa_data, ndev->addr_len);
         memcpy(ndev->dev_addr, sa->sa_data, ndev->addr_len);
-        emac_setmac(priv, EMAC_DEF_RX_CH, rxch->mac_addr);
+
+        /* If the interface is down - rxch is NULL. */
+        /* MAC address is configured only after the interface is enabled. */
+        if (netif_running(ndev)) {
+                memcpy(rxch->mac_addr, sa->sa_data, ndev->addr_len);
+                emac_setmac(priv, EMAC_DEF_RX_CH, rxch->mac_addr);
+        }
 
         if (netif_msg_drv(priv))
                 dev_notice(emac_dev, "DaVinci EMAC: emac_dev_setmac_addr %pM\n",