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Date:   Wed, 7 Feb 2018 12:13:09 +0100
From:   Jiri Benc <jbenc@redhat.com>
To:     ebiederm@xmission.com (Eric W. Biederman)
Cc:     Christian Brauner <christian.brauner@canonical.com>,
        Kirill Tkhai <ktkhai@virtuozzo.com>,
        Christian Brauner <christian.brauner@ubuntu.com>,
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        linux-kernel@vger.kernel.org, dsahern@gmail.com,
        davem@davemloft.net
Subject: Re: [PATCH net 1/1 v2] rtnetlink: require unique netns identifier
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On Tue, 06 Feb 2018 16:31:29 -0600, Eric W. Biederman wrote:
> Frankly.  If we are talking precedence it should be:
> fds
> netnsids
> pids

The current order is 1. pids, 2. fds, though. Not that it matters much,
see below.

> I do think it makes a lot of sense to error if someone passes in
> duplicate arguments.  AKA multiple attribute that could select for
> the same thing.   No one will do that deliberately.  It doesn't make
> sense.  So it is just a nonsense case we have to handle gracefully,
> and correctly.  With correctness being the most important as otherwise
> people might just send in nonsense to exploit bugs.

Completely agreed. Let's just start returning error if more than one of
the pid/fs/netnsid attributes is specified. I don't think this is going
to break any user. And we'll not have to care about the order.

> I agree refusing to combine multiple attributes for the same thing
> sounds the most sensible course.

Yes, please.

Thanks!

 Jiri