netdev - Re: [PATCH] net: dev_forward_skb(): Scrub packet's per-netns info only when crossing netns

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Date:   Tue, 20 Mar 2018 12:34:01 -0400 (EDT)
From:   David Miller <davem@...emloft.net>
To:     LIRAN.ALON@...CLE.COM
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        idan.brown@...CLE.COM, yuval.shaia@...CLE.COM
Subject: Re: [PATCH] net: dev_forward_skb(): Scrub packet's per-netns info
 only when crossing netns

From: Liran Alon <LIRAN.ALON@...CLE.COM>
Date: Tue, 20 Mar 2018 18:11:49 +0200

> 1. Do we want to make a flag for every bug that is user-space visible?
> I think there is place for consideration on a per-case basis. I still
> don't see how a user can utilize this behaviour. He is basically
> loosing information (skb->mark) without this patch.

And maybe people trying to work in this situation have added code to
get the mark set some other way, or to validate that it is in fact
zero after passing through, which we would break with this change.

If it's set to zero now, it's reasonable to expect it to be zero.

By changing it to non-zero, different rules and routes will match
and this for sure has potential to break things.