Re: [RCF] [PATCH] unprivileged mount/umount

From: Miklos Szeredi <miklos@szeredi.hu>
To: jamie@shareable.org
Cc: miklos@szeredi.hu, 7eggert@gmx.de, ericvh@gmail.com,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	smfrench@austin.rr.com, hch@infradead.org
Subject: Re: [RCF] [PATCH] unprivileged mount/umount
Date: Wed, 11 May 2005 23:20:37 +0200	[thread overview]
Message-ID: <E1DVydB-0002RF-00@dorka.pomaz.szeredi.hu> (raw)
In-Reply-To: <20050511210935.GA5093@mail.shareable.org> (message from Jamie Lokier on Wed, 11 May 2005 22:09:35 +0100)

> This is not a proposal - I'm not saying it's pretty - but a suggestion
> that you can use today.
> 
> Use clone(), and then have the child task open "/" and pass that file
> descriptor back to the parent process using a unix socket.  The child
> can exit and the parent can use the new namespace how it likes.  Short
> and sweet, and you can create as many namespaces as you like :)
> 
> That's mkdir done.

Right.

> You can't do a lot with the new namespace, because of the security
> restrictions on mount() on a foreign namespace.  That's what I meant
> about the "small fixes" - get rid of the current->namespace checks and
> it'll be usable.
> 
> I don't see the purpose of current->namespace and the associated mount
> restrictions at all.  I asked Al Viro what it's for, but haven't seen
> a reply :(  IMHO current->namespace should simply be removed, because the
> "current namespace" is represented just fine by
> current->fs->rootmnt->mnt_namespace.

I'll look at what it would take to remove current->namespace.

Miklos