Re: [PATCH] net: dsa: felix: Add NULL check for outer_tagging_rule()

[Michal Swiatkowski <michal.swiatkowski@linux.intel.com>]

On Thu, Feb 13, 2025 at 12:07:54PM +0800, Wentao Liang wrote:
> In felix_update_tag_8021q_rx_rules(), the return value of
> ocelot_vcap_block_find_filter_by_id() is not checked, which could
> lead to a NULL pointer dereference if the filter is not found.
> 
> Add the necessary check and use `continue` to skip the current CPU
> port if the filter is not found, ensuring that all CPU ports are
> processed.
> 
> Fixes: f1288fd7293b ("net: dsa: felix: fix VLAN tag loss on CPU reception with ocelot-8021q")
> Cc: stable@vger.kernel.org # 6.11+
> Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
> ---
>  drivers/net/dsa/ocelot/felix.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/dsa/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c
> index 3aa9c997018a..10ad43108b88 100644
> --- a/drivers/net/dsa/ocelot/felix.c
> +++ b/drivers/net/dsa/ocelot/felix.c
> @@ -348,6 +348,8 @@ static int felix_update_tag_8021q_rx_rules(struct dsa_switch *ds, int port,
>  
>  		outer_tagging_rule = ocelot_vcap_block_find_filter_by_id(block_vcap_es0,
>  									 cookie, false);
> +		if (!outer_tagging_rule)
> +			continue;
>  
>  		felix_update_tag_8021q_rx_rule(outer_tagging_rule, vlan_filtering);
>  

All other calls to ocelot_vcap_block_find_filter_by_id() are checked, so
looks correct, thanks.
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>

> -- 
> 2.42.0.windows.2