IPv6 XFRM policies may use different source and destination prefix
lengths. mlx5e_ipsec_policy_mask() builds the corresponding masks
independently, but setup_fte_addr6() installs each mask in the opposite
address field.

When the prefix lengths differ, this makes the source match use the
destination prefix and the destination match use the source prefix. The
resulting hardware rule can both miss traffic covered by the policy and
match traffic outside it.

Install each mask in its corresponding match field.

Fixes: ca7992f52c2c ("net/mlx5e: Properly match IPsec subnet addresses")
Cc: stable@vger.kernel.org
Assisted-by: LLM
Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_fs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_fs.c b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_fs.c
index 329608c59313b..8ffa8068e90ac 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_fs.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_fs.c
@@ -1564,14 +1564,14 @@ static void setup_fte_addr6(struct mlx5_flow_spec *spec,
 		memcpy(MLX5_ADDR_OF(fte_match_param, spec->match_value,
 				    outer_headers.src_ipv4_src_ipv6.ipv6_layout.ipv6), saddr, 16);
 		memcpy(MLX5_ADDR_OF(fte_match_param, spec->match_criteria,
-				    outer_headers.src_ipv4_src_ipv6.ipv6_layout.ipv6), dmask, 16);
+				    outer_headers.src_ipv4_src_ipv6.ipv6_layout.ipv6), smask, 16);
 	}
 
 	if (!addr6_all_zero(daddr)) {
 		memcpy(MLX5_ADDR_OF(fte_match_param, spec->match_value,
 				    outer_headers.dst_ipv4_dst_ipv6.ipv6_layout.ipv6), daddr, 16);
 		memcpy(MLX5_ADDR_OF(fte_match_param, spec->match_criteria,
-				    outer_headers.dst_ipv4_dst_ipv6.ipv6_layout.ipv6), smask, 16);
+				    outer_headers.dst_ipv4_dst_ipv6.ipv6_layout.ipv6), dmask, 16);
 	}
 }
 
-- 
2.53.0

On 17/09/2026 14:55, Andrea Parri wrote:
> IPv6 XFRM policies may use different source and destination prefix
> lengths. mlx5e_ipsec_policy_mask() builds the corresponding masks
> independently, but setup_fte_addr6() installs each mask in the opposite
> address field.
> 
> When the prefix lengths differ, this makes the source match use the
> destination prefix and the destination match use the source prefix. The
> resulting hardware rule can both miss traffic covered by the policy and
> match traffic outside it.
> 
> Install each mask in its corresponding match field.
> 
> Fixes: ca7992f52c2c ("net/mlx5e: Properly match IPsec subnet addresses")
> Cc: stable@vger.kernel.org
> Assisted-by: LLM
> Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
> ---
>   drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_fs.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_fs.c b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_fs.c
> index 329608c59313b..8ffa8068e90ac 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_fs.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_fs.c
> @@ -1564,14 +1564,14 @@ static void setup_fte_addr6(struct mlx5_flow_spec *spec,
>   		memcpy(MLX5_ADDR_OF(fte_match_param, spec->match_value,
>   				    outer_headers.src_ipv4_src_ipv6.ipv6_layout.ipv6), saddr, 16);
>   		memcpy(MLX5_ADDR_OF(fte_match_param, spec->match_criteria,
> -				    outer_headers.src_ipv4_src_ipv6.ipv6_layout.ipv6), dmask, 16);
> +				    outer_headers.src_ipv4_src_ipv6.ipv6_layout.ipv6), smask, 16);
>   	}
>   
>   	if (!addr6_all_zero(daddr)) {
>   		memcpy(MLX5_ADDR_OF(fte_match_param, spec->match_value,
>   				    outer_headers.dst_ipv4_dst_ipv6.ipv6_layout.ipv6), daddr, 16);
>   		memcpy(MLX5_ADDR_OF(fte_match_param, spec->match_criteria,
> -				    outer_headers.dst_ipv4_dst_ipv6.ipv6_layout.ipv6), smask, 16);
> +				    outer_headers.dst_ipv4_dst_ipv6.ipv6_layout.ipv6), dmask, 16);
>   	}
>   }
>   

Thanks for your patch.

Reviewed-by: Tariq Toukan <tariqt@nvidia.com>