Re: [PATCH 4.4 15/39] geneve: pull IP header before ECN decapsulation

From: Eric Dumazet
Date: Thu Dec 10 2020 - 09:34:56 EST


On Thu, Dec 10, 2020 at 3:26 PM Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> From: Eric Dumazet <edumazet@xxxxxxxxxx>
>
> IP_ECN_decapsulate() and IP6_ECN_decapsulate() assume
> IP header is already pulled.
>
> geneve does not ensure this yet.
>
> Fixing this generically in IP_ECN_decapsulate() and
> IP6_ECN_decapsulate() is not possible, since callers
> pass a pointer that might be freed by pskb_may_pull()
>
> syzbot reported :
>

Note that we had to revert this patch, so you can either scratp this
backport, or make sure to backport the revert.

Thanks !