Re: net/can: warning in raw_setsockopt/__alloc_pages_slowpath

[Oliver Hartkopp]

On 12/02/2016 04:42 PM, Marc Kleine-Budde wrote:
> 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 :)

:-)

Would you like to send a patch?

Regards,
Oliver