[net-next V2 08/15] net/mlx5e: Deny VLAN rewrite if there is no VLAN header match

[Saeed Mahameed]

From: Eli Britstein <el...@mellanox.com>

Rewrite of the packet in the VLAN offset may corrupt the packet if it's
not VLAN tagged. Deny the rewrite in this case.

Fixes: 37410902874c ("net/mlx5e: Support VLAN modify action")
Signed-off-by: Eli Britstein <el...@mellanox.com>
Reviewed-by: Roi Dayan <r...@mellanox.com>
Signed-off-by: Saeed Mahameed <sae...@mellanox.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c 
b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index 81f8ac569a0e..3a0854fbcfd4 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -2292,8 +2292,19 @@ static int add_vlan_rewrite_action(struct mlx5e_priv 
*priv, int namespace,
                .mangle.mask = ~(u32)be16_to_cpu(*(__be16 *)&mask16),
                .mangle.val = (u32)be16_to_cpu(*(__be16 *)&val16),
        };
+       void *headers_c, *headers_v;
        int err;
 
+       headers_c = get_match_headers_criteria(*action, &parse_attr->spec);
+       headers_v = get_match_headers_value(*action, &parse_attr->spec);
+
+       if (!(MLX5_GET(fte_match_set_lyr_2_4, headers_c, cvlan_tag) &&
+             MLX5_GET(fte_match_set_lyr_2_4, headers_v, cvlan_tag))) {
+               NL_SET_ERR_MSG_MOD(extack,
+                                  "VLAN rewrite action must have VLAN protocol 
match");
+               return -EOPNOTSUPP;
+       }
+
        if (act->vlan.prio) {
                NL_SET_ERR_MSG_MOD(extack, "Setting VLAN prio is not 
supported");
                return -EOPNOTSUPP;
-- 
2.20.1