Re: [PATCH net] udp: drop skb extensions before marking skb stateless

From: Byron Stanoszek
Date: Thu Nov 21 2019 - 15:46:08 EST


On Thu, 21 Nov 2019, Florian Westphal wrote:

Once udp stack has set the UDP_SKB_IS_STATELESS flag, later skb free
assumes all skb head state has been dropped already.

This will leak the extension memory in case the skb has extensions other
than the ipsec secpath, e.g. bridge nf data.

To fix this, set the UDP_SKB_IS_STATELESS flag only if we don't have
extensions or if the extension space can be free'd.

Fixes: 895b5c9f206eb7d25dc1360a ("netfilter: drop bridge nf reset from nf_reset")
Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
Reported-by: Byron Stanoszek <gandalf@xxxxxxxxx>
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>

I confirm that this fixes the memory leak on my systems. Thank you for the fast
turnaround.

Regards,
-Byron