brcmfmac: cleanup netdev transmit callback

The header of the ethernet packet is processed conditionally, but
the check is wrong as it checks skb length is at least ETH_ALEN. It
should check it is at least sizeof struct ethhdr instead.

Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 13 insertions, 9 deletions

diff --git a/drivers/net/wireless/brcm80211/brcmfmac/dhd_linux.c b/drivers/net/wireless/brcm80211/brcmfmac/dhd_linux.c
index a1ca6912ef28..9ca74118e131 100644
--- a/drivers/net/wireless/brcm80211/brcmfmac/dhd_linux.c
+++ b/drivers/net/wireless/brcm80211/brcmfmac/dhd_linux.c
@@ -165,6 +165,7 @@ static int brcmf_netdev_start_xmit(struct sk_buff *skb, struct net_device *ndev)
         int ret;
         struct brcmf_if *ifp = netdev_priv(ndev);
         struct brcmf_pub *drvr = ifp->drvr;
+        struct ethhdr *eh;
 
         brcmf_dbg(TRACE, "Enter\n");
 
@@ -202,17 +203,20 @@ static int brcmf_netdev_start_xmit(struct sk_buff *skb, struct net_device *ndev)
                 }
         }
 
-        /* Update multicast statistic */
-        if (skb->len >= ETH_ALEN) {
-                u8 *pktdata = (u8 *)(skb->data);
-                struct ethhdr *eh = (struct ethhdr *)pktdata;
-
-                if (is_multicast_ether_addr(eh->h_dest))
-                        drvr->tx_multicast++;
-                if (ntohs(eh->h_proto) == ETH_P_PAE)
-                        atomic_inc(&drvr->pend_8021x_cnt);
+        /* validate length for ether packet */
+        if (skb->len < sizeof(*eh)) {
+                ret = -EINVAL;
+                dev_kfree_skb(skb);
+                goto done;
         }
 
+        /* handle ethernet header */
+        eh = (struct ethhdr *)(skb->data);
+        if (is_multicast_ether_addr(eh->h_dest))
+                drvr->tx_multicast++;
+        if (ntohs(eh->h_proto) == ETH_P_PAE)
+                atomic_inc(&drvr->pend_8021x_cnt);
+
         /* If the protocol uses a data header, apply it */
         brcmf_proto_hdrpush(drvr, ifp->idx, skb);