From: Paolo Abeni <pabeni@xxxxxxxxxx> [ Upstream commit 4e81c0b3fa93d07653e2415fa71656b080a112fd ] When user-space sets the OVS_UFID_F_OMIT_* flags, and the relevant flow has no UFID, we can exceed the computed size, as ovs_nla_put_identifier() will always dump an OVS_FLOW_ATTR_KEY attribute. Take the above in account when computing the flow command message size. Fixes: 74ed7ab9264c ("openvswitch: Add support for unique flow IDs.") Reported-by: Qi Jun Ding <qding@xxxxxxxxxx> Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/openvswitch/datapath.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/net/openvswitch/datapath.c +++ b/net/openvswitch/datapath.c @@ -697,9 +697,13 @@ static size_t ovs_flow_cmd_msg_size(cons { size_t len = NLMSG_ALIGN(sizeof(struct ovs_header)); - /* OVS_FLOW_ATTR_UFID */ + /* OVS_FLOW_ATTR_UFID, or unmasked flow key as fallback + * see ovs_nla_put_identifier() + */ if (sfid && ovs_identifier_is_ufid(sfid)) len += nla_total_size(sfid->ufid_len); + else + len += nla_total_size(ovs_key_attr_size()); /* OVS_FLOW_ATTR_KEY */ if (!sfid || should_fill_key(sfid, ufid_flags))