[PATCH net-next v3 1/3] can: mscan: fix improper return if dlc < 8 in start_xmit function
Oliver Hartkopp
socketcan at hartkopp.net
Fri Jan 8 05:10:38 EST 2010
Wolfgang Grandegger wrote:
> The start_xmit function of the MSCAN Driver did return improperly if
> the CAN dlc check failed (skb not freed and invalid return code). This
> patch adds a proper check of the frame lenght and data size and returns
> now correctly.
> @@ -177,8 +177,13 @@ static netdev_tx_t mscan_start_xmit(struct sk_buff *skb, struct net_device *dev)
> int i, rtr, buf_id;
> u32 can_id;
>
> - if (frame->can_dlc > 8)
> - return -EINVAL;
> + if (skb->len != sizeof(*frame) || frame->can_dlc > 8) {
> + dev_err(dev->dev.parent,
> + "Dropping non-conform packet: len %u, can_dlc %u\n",
> + skb->len, frame->can_dlc);
> + kfree_skb(skb);
> + return NETDEV_TX_OK;
> + }
>
Hi Wolfgang,
i would suggest to remove the dev_err() which may flood the kernel log and add
dev->stats.tx_dropped++;
instead.
As discussed with DaveM on netdev-ML this 'silent' handling seems to be the
most appropriate approach to deal with invalid skbs.
We should update the other CAN drivers in a similar way, if this is ok for you.
Best regards,
Oliver
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