net: openvswitch: don't send internal clone attribute to the userspace.

BugLink: https://bugs.launchpad.net/bugs/1971497
[ Upstream commit 3f2a3050b4a3e7f32fc0ea3c9b0183090ae00522 ]

'OVS_CLONE_ATTR_EXEC' is an internal attribute that is used for
performance optimization inside the kernel.  It's added by the kernel
while parsing user-provided actions and should not be sent during the
flow dump as it's not part of the uAPI.

The issue doesn't cause any significant problems to the ovs-vswitchd
process, because reported actions are not really used in the
application lifecycle and only supposed to be shown to a human via
ovs-dpctl flow dump.  However, the action list is still incorrect
and causes the following error if the user wants to look at the
datapath flows:

  # ovs-dpctl add-dp system@ovs-system
  # ovs-dpctl add-flow "<flow match>" "clone(ct(commit),0)"
  # ovs-dpctl dump-flows
  <flow match>, packets:0, bytes:0, used:never,
    actions:clone(bad length 4, expected -1 for: action0(01 00 00 00),
                  ct(commit),0)

With the fix:

  # ovs-dpctl dump-flows
  <flow match>, packets:0, bytes:0, used:never,
    actions:clone(ct(commit),0)

Additionally fixed an incorrect attribute name in the comment.

Fixes: b233504033db ("openvswitch: kernel datapath clone action")
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Acked-by: Aaron Conole <aconole@redhat.com>
Link: https://lore.kernel.org/r/20220404104150.2865736-1-i.maximets@ovn.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 2c0f8cbc5c43b76594f8d863245b9f3e2cd91605..ae40593daf2146aa0eec6773bac9824c0aab228d 100644 (file)
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -1037,7 +1037,7 @@ static int clone(struct datapath *dp, struct sk_buff *skb,
        int rem = nla_len(attr);
        bool dont_clone_flow_key;
 
-       /* The first action is always 'OVS_CLONE_ATTR_ARG'. */
+       /* The first action is always 'OVS_CLONE_ATTR_EXEC'. */
        clone_arg = nla_data(attr);
        dont_clone_flow_key = nla_get_u32(clone_arg);
        actions = nla_next(clone_arg, &rem);

diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
index e4c23ae9cfe59e383ce4183e80c14367e548e467..d3f068ad154cb69409368c1f0142a7c40e3cbdeb 100644 (file)
--- a/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -3284,7 +3284,9 @@ static int clone_action_to_attr(const struct nlattr *attr,
        if (!start)
                return -EMSGSIZE;
 
-       err = ovs_nla_put_actions(nla_data(attr), rem, skb);
+       /* Skipping the OVS_CLONE_ATTR_EXEC that is always the first attribute. */
+       attr = nla_next(nla_data(attr), &rem);
+       err = ovs_nla_put_actions(attr, rem, skb);
 
        if (err)
                nla_nest_cancel(skb, start);