Re: net/can: warning in raw_setsockopt/__alloc_pages_slowpath

[Marc Kleine-Budde]

On 12/02/2016 04:11 PM, Oliver Hartkopp wrote:
> 
> 
> On 12/02/2016 02:24 PM, Marc Kleine-Budde wrote:
>> On 12/02/2016 01:43 PM, Andrey Konovalov wrote:
> 
> 
>>>  [<ffffffff8369e0de>] raw_setsockopt+0x1be/0x9f0 net/can/raw.c:506
>>
>> We should add a check for a sensible optlen....
>>
>>> static int raw_setsockopt(struct socket *sock, int level, int optname,
>>> 			  char __user *optval, unsigned int optlen)
>>> {
>>> 	struct sock *sk = sock->sk;
>>> 	struct raw_sock *ro = raw_sk(sk);
>>> 	struct can_filter *filter = NULL;  /* dyn. alloc'ed filters */
>>> 	struct can_filter sfilter;         /* single filter */
>>> 	struct net_device *dev = NULL;
>>> 	can_err_mask_t err_mask = 0;
>>> 	int count = 0;
>>> 	int err = 0;
>>>
>>> 	if (level != SOL_CAN_RAW)
>>> 		return -EINVAL;
>>>
>>> 	switch (optname) {
>>>
>>> 	case CAN_RAW_FILTER:
>>> 		if (optlen % sizeof(struct can_filter) != 0)
>>> 			return -EINVAL;
>>
>> here...
>>
>> 		if (optlen > 64 * sizeof(struct can_filter))
>> 			return -EINVAL;
>>
> 
> Agreed.
> 
> But what is sensible here?
> 64 filters is way to small IMO.
> 
> When thinking about picking a bunch of single CAN IDs I would tend to 
> something like 512 filters.

Ok - 64 was just an arbitrary chosen value for demonstration purposes :)

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |

Attachment: signature.asc
Description: OpenPGP digital signature