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; -- 2.7.4 _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev