On Fri, Sep 17, 2021 at 1:25 AM Jiasheng Jiang <jiash...@iscas.ac.cn> wrote: > > Just using 'rem > 0' might be unsafe, so it's better > to use the nla_ok() instead. > Because we can see from the nla_next() that > '*remaining' might be smaller than 'totlen'. And nla_ok() > will avoid it happening. > For example, ovs_dp_process_packet() -> ovs_execute_actions() > -> do_execute_actions() -> output_userspace(), and attr comes > from OVS_CB(skb)->input_vport,which restores the received packet > from the user space. > > Fixes: ccb1352e76cff0524e7ccb2074826a092dd13016 > ('net: Add Open vSwitch kernel components.') > Signed-off-by: Jiasheng Jiang <jiash...@iscas.ac.cn>
> --- > net/openvswitch/actions.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c > index c23537f..e8236dd 100644 > --- a/net/openvswitch/actions.c > +++ b/net/openvswitch/actions.c > @@ -915,8 +915,7 @@ static int output_userspace(struct datapath *dp, struct > sk_buff *skb, > upcall.cmd = OVS_PACKET_CMD_ACTION; > upcall.mru = OVS_CB(skb)->mru; > > - for (a = nla_data(attr), rem = nla_len(attr); rem > 0; > - a = nla_next(a, &rem)) { > + nla_for_each_nested(a, attr, rem) { > switch (nla_type(a)) { > case OVS_USERSPACE_ATTR_USERDATA: > upcall.userdata = a; These nl-attributes are built and verified at time of OVS flow install, so the rest of checks in nla_ok, is not required. _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev