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

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>
---
 drivers/net/can/mscan/mscan.c |   11 ++++++++---
 1 files changed, 8 insertions(+), 3 deletions(-)

On Sat, Jan 02, 2010 at 09:17:52AM +0100, Wolfgang Grandegger wrote:
> 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.

A few little things, but in general:

Acked-by: Wolfram Sang <w.sang@pengutronix.de>

> 
> Signed-off-by: Wolfgang Grandegger <wg@denx.de>
> ---
>  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 07346f8..abdf5e8 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 paket: len %d, can_dlc %d\n",

s/paket/packet/

> +			skb->len, frame->can_dlc);

Also, shouldn't it rather be %u (sk_buff->len is unsigned int)?

> +		kfree_skb(skb);
> +		return  NETDEV_TX_OK;
> +	}
>  
>  	out_8(&regs->cantier, 0);
>  
> -- 
> 1.6.2.5
>

Wolfram Sang wrote:
> On Sat, Jan 02, 2010 at 09:17:52AM +0100, Wolfgang Grandegger wrote:
>> 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.
> 
> A few little things, but in general:
> 
> Acked-by: Wolfram Sang <w.sang@pengutronix.de>
> 
>> Signed-off-by: Wolfgang Grandegger <wg@denx.de>
>> ---
>>  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 07346f8..abdf5e8 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 paket: len %d, can_dlc %d\n",
> 
> s/paket/packet/
> 
>> +			skb->len, frame->can_dlc);
> 
> Also, shouldn't it rather be %u (sk_buff->len is unsigned int)?

Will fix both issue.

Wolfgang.