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Subject: Re: plan9 semantics on Linux - mount namespaces
To:     Richard Weinberger <richard@sigma-star.at>,
        Aleksa Sarai <asarai@suse.de>
Cc:     Linux Containers <containers@lists.linux-foundation.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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 <4864d279-9a3f-eaf4-c297-ea34be604e41@metux.net>
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From:   Enrico Weigelt <lkml@metux.net>
Organization: metux IT consult
Message-ID: <a2a6f189-008e-38f2-afcb-b9393d8d440a@metux.net>
Date:   Wed, 14 Feb 2018 15:03:55 +0100
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On 14.02.2018 13:53, Richard Weinberger wrote:

> It does what you ask it for. > Also see the --setgroups switch.> AFAICT --setgroups=deny is the new 
default, then your command line should just> work. Maybe your unshare 
tool is too old.
Also doesn't help:

daemon@alphabox:~ unshare -U -r --setgroups=deny
unshare: can't open '/proc/self/setgroups': Permission denied

>> What I'd like to achieve is that processes can manipulate their private >> namespace at will and mount other filesystems (primarily 9p and 
fuse).>>>> For that, I need to get rid of setuid (and per-file caps) for 
these>> private namespaces.>
> This is exactly why we have the user namespace.
> In the user namespace you can create your own mount namespace and do (almost)
> whatever you want.

What's the exact relation between user and mnt namespace ?
Why do I need an own user ns for private mnt ns ? (except for the suid
bit, which I wanna get rid of anyways).


--mtx

-- 
Enrico Weigelt, metux IT consult
Free software and Linux embedded engineering
info@metux.net -- +49-151-27565287