| Message ID | 1631867098-3891002-1-git-send-email-jiasheng@iscas.ac.cn (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | None | expand |
On Fri, Sep 17, 2021 at 1:25 AM Jiasheng Jiang <jiasheng@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 <jiasheng@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.
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;
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 <jiasheng@iscas.ac.cn> --- net/openvswitch/actions.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)