Linux Ethernet Bridging - Jan 2022 - [Bridge] [PATCH] net: bridge: vlan: fix memory leak in __allowed_ingress

When using per-vlan state, if vlan snooping and stats are disabled,
untagged or priority-tagged ingress frame will go to check pvid state.
If the port state is forwarding and the pvid state is not
learning/forwarding, untagged or priority-tagged frame will be dropped
but skb memory is not freed.
Should free skb when __allowed_ingress returns false.

Signed-off-by: Tim Yi <tim.yi at pica8.com>
---
 net/bridge/br_vlan.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
index 84ba456a78cc..88c4297cddee 100644
--- a/net/bridge/br_vlan.c
+++ b/net/bridge/br_vlan.c
@@ -560,10 +560,10 @@ static bool __allowed_ingress(const struct net_bridge *br,
 		    !br_opt_get(br, BROPT_VLAN_STATS_ENABLED)) {
 			if (*state == BR_STATE_FORWARDING) {
 				*state = br_vlan_get_pvid_state(vg);
-				return br_vlan_state_allowed(*state, true);
-			} else {
-				return true;
+				if (!br_vlan_state_allowed(*state, true))
+					goto drop;
 			}
+			return true;
 		}
 	}
 	v = br_vlan_find(vg, *vid);
-- 
2.28.0.618.g9bc233ae1c

On 27/01/2022 09:49, Tim Yi wrote:
> When using per-vlan state, if vlan snooping and stats are disabled,
> untagged or priority-tagged ingress frame will go to check pvid state.
> If the port state is forwarding and the pvid state is not
> learning/forwarding, untagged or priority-tagged frame will be dropped
> but skb memory is not freed.
> Should free skb when __allowed_ingress returns false.
> 
> Signed-off-by: Tim Yi <tim.yi at pica8.com>
> ---
>  net/bridge/br_vlan.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
> index 84ba456a78cc..88c4297cddee 100644
> --- a/net/bridge/br_vlan.c
> +++ b/net/bridge/br_vlan.c
> @@ -560,10 +560,10 @@ static bool __allowed_ingress(const struct net_bridge
*br,
>  		    !br_opt_get(br, BROPT_VLAN_STATS_ENABLED)) {
>  			if (*state == BR_STATE_FORWARDING) {
>  				*state = br_vlan_get_pvid_state(vg);
> -				return br_vlan_state_allowed(*state, true);
> -			} else {
> -				return true;
> +				if (!br_vlan_state_allowed(*state, true))
> +					goto drop;
>  			}
> +			return true;
>  		}
>  	}
>  	v = br_vlan_find(vg, *vid);


Good catch, also should go to stable, here's the appropriate fixes tag.

Fixes: a580c76d534c ("net: bridge: vlan: add per-vlan state")
Acked-by: Nikolay Aleksandrov <nikolay at nvidia.com>

Thanks,
 Nik

Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski <kuba at kernel.org>:

On Thu, 27 Jan 2022 15:49:53 +0800 you wrote:
> When using per-vlan state, if vlan snooping and stats are disabled,
> untagged or priority-tagged ingress frame will go to check pvid state.
> If the port state is forwarding and the pvid state is not
> learning/forwarding, untagged or priority-tagged frame will be dropped
> but skb memory is not freed.
> Should free skb when __allowed_ingress returns false.
> 
> [...]
Here is the summary with links:
  - net: bridge: vlan: fix memory leak in __allowed_ingress
    https://git.kernel.org/netdev/net/c/fd20d9738395

You are awesome, thank you!
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