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

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Message-ID: <5AB13953.3000606@ORACLE.COM>
Date:   Tue, 20 Mar 2018 18:39:47 +0200
From:   Liran Alon <LIRAN.ALON@...CLE.COM>
To:     David Miller <davem@...emloft.net>
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



On 20/03/18 18:34, David Miller wrote:
> 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.
>

OK.

What is your opinion in regards if it's OK to put the flag enabling this 
"fix" in /proc/sys/net/core? Do you think it's sufficient?