net/mlx5e: fix double free of encap_header in update funcs

Follow up to the previous patch to fix the same issue for
mlx5e_tc_tun_update_header_ipv4{6} when mlx5_packet_reformat_alloc()
fails.

When mlx5_packet_reformat_alloc() fails, the encap_header allocated in
mlx5e_tc_tun_update_header_ipv4{6} will be released within it. However,
e->encap_header is already set to the previously freed encap_header
before mlx5_packet_reformat_alloc(). As a result, the later
mlx5e_encap_put() will free e->encap_header again, causing a double free
issue.

mlx5e_encap_put()
     --> mlx5e_encap_dealloc()
         --> kfree(e->encap_header)

This patch fix it by not setting e->encap_header until
mlx5_packet_reformat_alloc() success.

Fixes: a54e20b ("net/mlx5e: Add basic TC tunnel set action for SRIOV offloads")
Signed-off-by: Gavin Li <gavinl@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Link: https://lore.kernel.org/r/20231114215846.5902-7-saeed@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: GavinLi-NV

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

@@ -403,16 +403,12 @@ int mlx5e_tc_tun_update_header_ipv4(struct mlx5e_priv *priv,
 	if (err)
 		goto free_encap;
 
-	e->encap_size = ipv4_encap_size;
-	kfree(e->encap_header);
-	e->encap_header = encap_header;
-
 	if (!(nud_state & NUD_VALID)) {
 		neigh_event_send(attr.n, NULL);
 		/* the encap entry will be made valid on neigh update event
 		 * and not used before that.
 		 */
-		goto release_neigh;
+		goto free_encap;
 	}
 
 	memset(&reformat_params, 0, sizeof(reformat_params));
@@ -426,6 +422,10 @@ int mlx5e_tc_tun_update_header_ipv4(struct mlx5e_priv *priv,
 		goto free_encap;
 	}
 
+	e->encap_size = ipv4_encap_size;
+	kfree(e->encap_header);
+	e->encap_header = encap_header;
+
 	e->flags |= MLX5_ENCAP_ENTRY_VALID;
 	mlx5e_rep_queue_neigh_stats_work(netdev_priv(attr.out_dev));
 	mlx5e_route_lookup_ipv4_put(&attr);
@@ -669,16 +669,12 @@ int mlx5e_tc_tun_update_header_ipv6(struct mlx5e_priv *priv,
 	if (err)
 		goto free_encap;
 
-	e->encap_size = ipv6_encap_size;
-	kfree(e->encap_header);
-	e->encap_header = encap_header;
-
 	if (!(nud_state & NUD_VALID)) {
 		neigh_event_send(attr.n, NULL);
 		/* the encap entry will be made valid on neigh update event
 		 * and not used before that.
 		 */
-		goto release_neigh;
+		goto free_encap;
 	}
 
 	memset(&reformat_params, 0, sizeof(reformat_params));
@@ -692,6 +688,10 @@ int mlx5e_tc_tun_update_header_ipv6(struct mlx5e_priv *priv,
 		goto free_encap;
 	}
 
+	e->encap_size = ipv6_encap_size;
+	kfree(e->encap_header);
+	e->encap_header = encap_header;
+
 	e->flags |= MLX5_ENCAP_ENTRY_VALID;
 	mlx5e_rep_queue_neigh_stats_work(netdev_priv(attr.out_dev));
 	mlx5e_route_lookup_ipv6_put(&attr);