[PATCH 4.14 171/209] openvswitch: fix flow command message size

Greg Kroah-Hartman
2019-12-04T18:08:08Z

From: Paolo Abeni <pabeni@redhat.com>

[ 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@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/openvswitch/datapath.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -724,9 +724,13 @@ 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))