linux-kernel - Re: [PATCH net-next v24 16/23] ovpn: implement keepalive mechanism

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Z-vhVdMThx7NQgW0@krikkit>
Date: Tue, 1 Apr 2025 14:51:33 +0200
From: Sabrina Dubroca <sd@...asysnail.net>
To: Antonio Quartulli <antonio@...nvpn.net>
Cc: netdev@...r.kernel.org, Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Donald Hunter <donald.hunter@...il.com>,
	Shuah Khan <shuah@...nel.org>, ryazanov.s.a@...il.com,
	Andrew Lunn <andrew+netdev@...n.ch>,
	Simon Horman <horms@...nel.org>, linux-kernel@...r.kernel.org,
	linux-kselftest@...r.kernel.org, Xiao Liang <shaw.leon@...il.com>
Subject: Re: [PATCH net-next v24 16/23] ovpn: implement keepalive mechanism

2025-03-18, 02:40:51 +0100, Antonio Quartulli wrote:
> @@ -124,6 +154,13 @@ void ovpn_decrypt_post(void *data, int ret)
>  			goto drop;
>  		}
>  
> +		if (ovpn_is_keepalive(skb)) {
> +			net_dbg_ratelimited("%s: ping received from peer %u\n",
> +					    netdev_name(peer->ovpn->dev),
> +					    peer->id);
> +			goto drop_nocount;
> +		}
> +
>  		net_info_ratelimited("%s: unsupported protocol received from peer %u\n",
>  				     netdev_name(peer->ovpn->dev), peer->id);
>  		goto drop;
> @@ -149,6 +186,7 @@ void ovpn_decrypt_post(void *data, int ret)
>  drop:
>  	if (unlikely(skb))
>  		dev_core_stats_rx_dropped_inc(peer->ovpn->dev);
> +drop_nocount:
>  	if (likely(peer))
>  		ovpn_peer_put(peer);
>  	if (likely(ks))
>  	kfree_skb(skb);
>  }

Again a small thing: in the case of a keepalive message, it would also
be nice to use consume_skb instead of kfree_skb. Quoting from the doc
for consume_skb:

 *	Functions identically to kfree_skb, but kfree_skb assumes that the frame
 *	is being dropped after a failure and notes that



Something like this maybe (not compiled):

	/* skb is passed to upper layer - don't free it */
	skb = NULL;
drop:
	if (unlikely(skb))
		dev_core_stats_rx_dropped_inc(peer->ovpn->dev);
	kfree_skb(skb);
	skb = NULL;
drop_nocount:
	if (likely(peer))
		ovpn_peer_put(peer);
	if (likely(ks))
		ovpn_crypto_key_slot_put(ks);
	consume_skb(skb);



-- 
Sabrina