From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ram Pai Subject: Re: [Devel] Re: [patch 05/10] add "permit user mounts in new namespace" clone flag Date: Mon, 16 Apr 2007 01:47:00 -0700 Message-ID: <1176713221.9488.17.camel@ram.us.ibm.com> References: <20070412164541.580374744@szeredi.hu> <20070412164620.588752236@szeredi.hu> <20070412203208.GG27772@sergelap.austin.ibm.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: "Serge E. Hallyn" , Miklos Szeredi , linux-kernel@vger.kernel.org, containers@lists.osdl.org, viro@ftp.linux.org.uk, linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org To: devel@openvz.org Return-path: Received: from e4.ny.us.ibm.com ([32.97.182.144]:60952 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965352AbXDPIss (ORCPT ); Mon, 16 Apr 2007 04:48:48 -0400 In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org > > "Serge E. Hallyn" writes: > > > Quoting Miklos Szeredi (miklos@szeredi.hu): > >> From: Miklos Szeredi > >> > >> If CLONE_NEWNS and CLONE_NEWNS_USERMNT are given to clone(2) or > >> unshare(2), then allow user mounts within the new namespace. > >> > >> This is not flexible enough, because user mounts can't be enabled > for > >> the initial namespace. > >> > >> The remaining clone bits also getting dangerously few... > >> > >> Alternatives are: > >> > >> - prctl() flag > >> - setting through the containers filesystem > > > > Sorry, I know I had mentioned it, but this is definately my least > > favorite approach. > > > > Curious whether are any other suggestions/opinions from the > containers > > list? > > Given the existence of shared subtrees allowing/denying this at the > mount > namespace level is silly and wrong. > > If we need more than just the filesystem permission checks can we > make it a mount flag settable with mount and remount that allows > non-privileged users the ability to create mount points under it > in directories they have full read/write access to. Also for bind-mount and remount operations the flag has to be propagated down its propagation tree. Otherwise a unpriviledged mount in a shared mount wont get reflected in its peers and slaves, leading to unidentical shared-subtrees. RP > > I don't like the use of clone flags for this purpose but in this > case the shared subtress are a much more fundamental reasons for not > doing this at the namespace level. > > Eric > _______________________________________________ > Containers mailing list > Containers@lists.linux-foundation.org > https://lists.linux-foundation.org/mailman/listinfo/containers