diff mbox

[net-next,v3,1/3] can: mscan: fix improper return if dlc < 8 in start_xmit function

Message ID 1262873421-6863-2-git-send-email-wg@grandegger.com (mailing list archive)
State Not Applicable
Headers show

Commit Message

Wolfgang Grandegger Jan. 7, 2010, 2:10 p.m. UTC 
From: Wolfgang Grandegger <wg@denx.de>

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. Furthermore, a typo has been fixed.

Signed-off-by: Wolfgang Grandegger <wg@denx.de>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
---
 drivers/net/can/mscan/mscan.c |   11 ++++++++---
 1 files changed, 8 insertions(+), 3 deletions(-)

Comments

Oliver Hartkopp Jan. 7, 2010, 6:10 p.m. UTC | #1 
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
diff mbox

Patch

diff --git a/drivers/net/can/mscan/mscan.c b/drivers/net/can/mscan/mscan.c
index 07346f8..955a164 100644
--- a/drivers/net/can/mscan/mscan.c
+++ b/drivers/net/can/mscan/mscan.c
@@ -4,7 +4,7 @@ 
  * Copyright (C) 2005-2006 Andrey Volkov <avolkov@varma-el.com>,
  *                         Varma Electronics Oy
  * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
- * Copytight (C) 2008-2009 Pengutronix <kernel@pengutronix.de>
+ * Copyright (C) 2008-2009 Pengutronix <kernel@pengutronix.de>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the version 2 of the GNU General Public License
@@ -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;
+	}
 
 	out_8(&regs->cantier, 0);