# Re: \[PATCH net-next v2 1/3\] can: mscan: fix improper return if dlc \< 8 in start\_xmit function

- From: Wolfram Sang \<hidden\>
- Date: 2010-01-06 14:33:37 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2010/01/8050310
- Thread: https://ratatoskr.run/linux-devicetree/2010/01/8050310/t.md

```text
On Tue, Jan 05, 2010 at 08:19:27PM +0100, Wolfgang Grandegger wrote:
> From: Wolfgang Grandegger <redacted>
> 
> 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 <redacted>
> Acked-by: Wolfram Sang <redacted>
> ---
>  drivers/net/can/mscan/mscan.c |   11 ++++++++---
>  1 files changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/can/mscan/mscan.c b/drivers/net/can/mscan/mscan.c
> index bb06dfb..7df950e 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 [ref],
>   *                         Varma Electronics Oy
>   * Copyright (C) 2008-2009 Wolfgang Grandegger [ref]
> - * Copytight (C) 2008-2009 Pengutronix [ref]
> + * Copyright (C) 2008-2009 Pengutronix [ref]
>   *
>   * 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;

Double space.

> +	}
>  
>  	out_8(&regs->cantier, 0);
>  
> -- 
> 1.6.2.5
> 

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
```

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