Re: [PATCH net-next v3 1/3] can: mscan: fix improper return if dlc < 8 in start_xmit function
From: Oliver Hartkopp <hidden>
Date: 2010-01-07 18:10:38
Also in:
linuxppc-dev, netdev
Possibly related (same subject, not in this thread)
- 2010-01-07 · [PATCH net-next v3 1/3] can: mscan: fix improper return if dlc < 8 in start_xmit function · Wolfgang Grandegger <hidden>
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.
quoted hunk
@@ -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