> -----Original Message----- > From: Stephen Hemminger [mailto:step...@networkplumber.org] > Sent: 2017年9月21日 23:10 > To: Zhang Shengju <zhangshen...@cmss.chinamobile.com> > Cc: da...@davemloft.net; will...@google.com; netdev@vger.kernel.org > Subject: Re: [net-next 2/2] ifb: add device MTU validation check > > On Thu, 21 Sep 2017 21:32:02 +0800 > Zhang Shengju <zhangshen...@cmss.chinamobile.com> wrote: > > > Currently, any mtu value can be assigned when adding a new ifb device: > > [~]# ip link add name ifb2 mtu 100000 type ifb [~]# ip link show ifb2 > > 18: ifb2: <BROADCAST,NOARP> mtu 100000 qdisc noop state DOWN mode > DEFAULT group default qlen 32 > > link/ether 7a:bf:f4:63:da:d1 brd ff:ff:ff:ff:ff:ff > > > > This patch adds device MTU validation check. > > > > Signed-off-by: Zhang Shengju <zhangshen...@cmss.chinamobile.com> > > --- > > drivers/net/ifb.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/drivers/net/ifb.c b/drivers/net/ifb.c index > > 8870bd2..ce84ad2 100644 > > --- a/drivers/net/ifb.c > > +++ b/drivers/net/ifb.c > > @@ -282,6 +282,14 @@ static int ifb_validate(struct nlattr *tb[], struct > nlattr *data[], > > if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) > > return -EADDRNOTAVAIL; > > } > > + > > + if (tb[IFLA_MTU]) { > > + u32 mtu = nla_get_u32(tb[IFLA_MTU]); > > + > > + if (mtu < ETH_MIN_MTU || mtu > ETH_DATA_LEN) > > + return -EINVAL; > > + } > > + > > return 0; > > } > > > > What about running ifb with packets coming from devices with jumbo frames? > Also since ifb is an input only device, MTU doesn't matter.
Actually ifb_setup() function setup ifb valid MTU range: [68, 1500], and this will be check at dev_set_mtu() function. You can't setup mtu out of this range after creation, but you can set any value when adding new ifb device. This is inconsistent, and I think we should add this check at creation time BRs, ZSJ
