net/mlx5: E-Switch, Set correctly vport destination

The cited commit moved from using reformat_id integer to packet_reformat
pointer which introduced the possibility to null pointer dereference.
When setting packet reformat flag and pkt_reformat pointer must
exists so checking MLX5_ESW_DEST_ENCAP is not enough, we need
to make sure the pkt_reformat is valid and check for MLX5_ESW_DEST_ENCAP_VALID.
If the dest encap valid flag does not exists then pkt_reformat can be
either invalid address or null.
Also, to make sure we don't try to access invalid pkt_reformat set it to
null when invalidated and invalidate it before calling add flow code as
its logically more correct and to be safe.

Fixes: 2b688ea5 ("net/mlx5: Add flow steering actions to fs_cmd shim layer")
Signed-off-by: Roi Dayan <roid@nvidia.com>
Reviewed-by: Chris Mi <cmi@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun_encap.c

@@ -224,15 +224,16 @@ void mlx5e_tc_encap_flows_del(struct mlx5e_priv *priv,
 	list_for_each_entry(flow, flow_list, tmp_list) {
 		if (!mlx5e_is_offloaded_flow(flow) || flow_flag_test(flow, SLOW))
 			continue;
-		spec = &flow->attr->parse_attr->spec;
-
-		/* update from encap rule to slow path rule */
-		rule = mlx5e_tc_offload_to_slow_path(esw, flow, spec);
 
 		attr = mlx5e_tc_get_encap_attr(flow);
 		esw_attr = attr->esw_attr;
 		/* mark the flow's encap dest as non-valid */
 		esw_attr->dests[flow->tmp_entry_index].flags &= ~MLX5_ESW_DEST_ENCAP_VALID;
+		esw_attr->dests[flow->tmp_entry_index].pkt_reformat = NULL;
+
+		/* update from encap rule to slow path rule */
+		spec = &flow->attr->parse_attr->spec;
+		rule = mlx5e_tc_offload_to_slow_path(esw, flow, spec);
 
 		if (IS_ERR(rule)) {
 			err = PTR_ERR(rule);
@@ -251,6 +252,7 @@ void mlx5e_tc_encap_flows_del(struct mlx5e_priv *priv,
 	/* we know that the encap is valid */
 	e->flags &= ~MLX5_ENCAP_ENTRY_VALID;
 	mlx5_packet_reformat_dealloc(priv->mdev, e->pkt_reformat);
+	e->pkt_reformat = NULL;
 }
 
 static void mlx5e_take_tmp_flow(struct mlx5e_tc_flow *flow,

drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c

@@ -433,7 +433,7 @@ esw_setup_vport_dest(struct mlx5_flow_destination *dest, struct mlx5_flow_act *f
 		    mlx5_lag_mpesw_is_activated(esw->dev))
 			dest[dest_idx].type = MLX5_FLOW_DESTINATION_TYPE_UPLINK;
 	}
-	if (esw_attr->dests[attr_idx].flags & MLX5_ESW_DEST_ENCAP) {
+	if (esw_attr->dests[attr_idx].flags & MLX5_ESW_DEST_ENCAP_VALID) {
 		if (pkt_reformat) {
 			flow_act->action |= MLX5_FLOW_CONTEXT_ACTION_PACKET_REFORMAT;
 			flow_act->pkt_reformat = esw_attr->dests[attr_idx].pkt_reformat;