can: Unify droping of invalid tx skbs and netdev stats

To prevent the CAN drivers to operate on invalid socketbuffers the skbs are
now checked and silently dropped at the xmit-function consistently.

Also the netdev stats are consistently using the CAN data length code (dlc)
for [rx|tx]_bytes now.

Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

8 files changed, 26 insertions, 13 deletions

diff --git a/drivers/net/can/at91_can.c b/drivers/net/can/at91_can.c
index 166cc7e579c0..f7287497ba6e 100644
--- a/drivers/net/can/at91_can.c
+++ b/drivers/net/can/at91_can.c
@@ -342,6 +342,9 @@ static netdev_tx_t at91_start_xmit(struct sk_buff *skb, struct net_device *dev)
         unsigned int mb, prio;
         u32 reg_mid, reg_mcr;
 
+        if (can_dropped_invalid_skb(dev, skb))
+                return NETDEV_TX_OK;
+
         mb = get_tx_next_mb(priv);
         prio = get_tx_next_prio(priv);
 
diff --git a/drivers/net/can/bfin_can.c b/drivers/net/can/bfin_can.c
index 0ec1524523cc..7e1926e79e98 100644
--- a/drivers/net/can/bfin_can.c
+++ b/drivers/net/can/bfin_can.c
@@ -318,6 +318,9 @@ static int bfin_can_start_xmit(struct sk_buff *skb, struct net_device *dev)
         u16 val;
         int i;
 
+        if (can_dropped_invalid_skb(dev, skb))
+                return NETDEV_TX_OK;
+
         netif_stop_queue(dev);
 
         /* fill id */
diff --git a/drivers/net/can/mcp251x.c b/drivers/net/can/mcp251x.c
index 1a72ca066a17..afa2fa45fed9 100644
--- a/drivers/net/can/mcp251x.c
+++ b/drivers/net/can/mcp251x.c
@@ -494,12 +494,8 @@ static netdev_tx_t mcp251x_hard_start_xmit(struct sk_buff *skb,
                 return NETDEV_TX_BUSY;
         }
 
-        if (skb->len != sizeof(struct can_frame)) {
-                dev_err(&spi->dev, "dropping packet - bad length\n");
-                dev_kfree_skb(skb);
-                net->stats.tx_dropped++;
+        if (can_dropped_invalid_skb(net, skb))
                 return NETDEV_TX_OK;
-        }
 
         netif_stop_queue(net);
         priv->tx_skb = skb;
diff --git a/drivers/net/can/mscan/mscan.c b/drivers/net/can/mscan/mscan.c
index 500d18918bd5..40827c128b65 100644
--- a/drivers/net/can/mscan/mscan.c
+++ b/drivers/net/can/mscan/mscan.c
@@ -204,11 +204,8 @@ static netdev_tx_t mscan_start_xmit(struct sk_buff *skb, struct net_device *dev)
         int i, rtr, buf_id;
         u32 can_id;
 
-        if (skb->len != sizeof(*frame) || frame->can_dlc > 8) {
-                kfree_skb(skb);
-                dev->stats.tx_dropped++;
+        if (can_dropped_invalid_skb(dev, skb))
                 return NETDEV_TX_OK;
-        }
 
         out_8(&regs->cantier, 0);
 
diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja1000/sja1000.c
index 542a4f7255b4..345304d779b9 100644
--- a/drivers/net/can/sja1000/sja1000.c
+++ b/drivers/net/can/sja1000/sja1000.c
@@ -249,6 +249,9 @@ static netdev_tx_t sja1000_start_xmit(struct sk_buff *skb,
         uint8_t dreg;
         int i;
 
+        if (can_dropped_invalid_skb(dev, skb))
+                return NETDEV_TX_OK;
+
         netif_stop_queue(dev);
 
         fi = dlc = cf->can_dlc;
diff --git a/drivers/net/can/ti_hecc.c b/drivers/net/can/ti_hecc.c
index 5c993c2da528..7d370e32a7a8 100644
--- a/drivers/net/can/ti_hecc.c
+++ b/drivers/net/can/ti_hecc.c
@@ -477,6 +477,9 @@ static netdev_tx_t ti_hecc_xmit(struct sk_buff *skb, struct net_device *ndev)
         u32 mbxno, mbx_mask, data;
         unsigned long flags;
 
+        if (can_dropped_invalid_skb(ndev, skb))
+                return NETDEV_TX_OK;
+
         mbxno = get_tx_head_mb(priv);
         mbx_mask = BIT(mbxno);
         spin_lock_irqsave(&priv->mbx_lock, flags);
@@ -491,7 +494,6 @@ static netdev_tx_t ti_hecc_xmit(struct sk_buff *skb, struct net_device *ndev)
         spin_unlock_irqrestore(&priv->mbx_lock, flags);
 
         /* Prepare mailbox for transmission */
-        data = min_t(u8, cf->can_dlc, 8);
         if (cf->can_id & CAN_RTR_FLAG) /* Remote transmission request */
                 data |= HECC_CANMCF_RTR;
         data |= get_tx_head_prio(priv) << 8;
diff --git a/drivers/net/can/usb/ems_usb.c b/drivers/net/can/usb/ems_usb.c
index efbb05c71bf4..ddb17e256656 100644
--- a/drivers/net/can/usb/ems_usb.c
+++ b/drivers/net/can/usb/ems_usb.c
@@ -767,6 +767,9 @@ static netdev_tx_t ems_usb_start_xmit(struct sk_buff *skb, struct net_device *ne
         size_t size = CPC_HEADER_SIZE + CPC_MSG_HEADER_LEN
                         + sizeof(struct cpc_can_msg);
 
+        if (can_dropped_invalid_skb(netdev, skb))
+                return NETDEV_TX_OK;
+
         /* create a URB, and a buffer for it, and copy the data to the URB */
         urb = usb_alloc_urb(0, GFP_ATOMIC);
         if (!urb) {
diff --git a/drivers/net/can/vcan.c b/drivers/net/can/vcan.c
index 80ac56313981..d124d837ae58 100644
--- a/drivers/net/can/vcan.c
+++ b/drivers/net/can/vcan.c
@@ -47,6 +47,7 @@
 #include <linux/if_arp.h>
 #include <linux/if_ether.h>
 #include <linux/can.h>
+#include <linux/can/dev.h>
 #include <net/rtnetlink.h>
 
 static __initdata const char banner[] =
@@ -70,10 +71,11 @@ MODULE_PARM_DESC(echo, "Echo sent frames (for testing). Default: 0 (Off)");
 
 static void vcan_rx(struct sk_buff *skb, struct net_device *dev)
 {
+        struct can_frame *cf = (struct can_frame *)skb->data;
         struct net_device_stats *stats = &dev->stats;
 
         stats->rx_packets++;
-        stats->rx_bytes += skb->len;
+        stats->rx_bytes += cf->can_dlc;
 
         skb->protocol  = htons(ETH_P_CAN);
         skb->pkt_type  = PACKET_BROADCAST;
@@ -85,11 +87,15 @@ static void vcan_rx(struct sk_buff *skb, struct net_device *dev)
 
 static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)
 {
+        struct can_frame *cf = (struct can_frame *)skb->data;
         struct net_device_stats *stats = &dev->stats;
         int loop;
 
+        if (can_dropped_invalid_skb(dev, skb))
+                return NETDEV_TX_OK;
+
         stats->tx_packets++;
-        stats->tx_bytes += skb->len;
+        stats->tx_bytes += cf->can_dlc;
 
         /* set flag whether this packet has to be looped back */
         loop = skb->pkt_type == PACKET_LOOPBACK;
@@ -103,7 +109,7 @@ static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)
                          * CAN core already did the echo for us
                          */
                         stats->rx_packets++;
-                        stats->rx_bytes += skb->len;
+                        stats->rx_bytes += cf->can_dlc;
                 }
                 kfree_skb(skb);
                 return NETDEV_TX_OK;