From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0866CC433E2 for ; Fri, 28 Aug 2020 15:21:24 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CBE6020757 for ; Fri, 28 Aug 2020 15:21:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CBE6020757 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=xmission.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=containers-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id A5ACB87F86; Fri, 28 Aug 2020 15:21:23 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id apVlMiyrGbOb; Fri, 28 Aug 2020 15:21:22 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by whitealder.osuosl.org (Postfix) with ESMTP id 107B788242; Fri, 28 Aug 2020 15:21:08 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id EAF69C016F; Fri, 28 Aug 2020 15:21:07 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id B7319C0051 for ; Fri, 28 Aug 2020 15:21:06 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id 74C99885C8 for ; Fri, 28 Aug 2020 15:21:06 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id LiiL-rBKu3Sm for ; Fri, 28 Aug 2020 15:21:05 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from out01.mta.xmission.com (out01.mta.xmission.com [166.70.13.231]) by hemlock.osuosl.org (Postfix) with ESMTPS id D9C738776C for ; Fri, 28 Aug 2020 15:21:05 +0000 (UTC) Received: from in01.mta.xmission.com ([166.70.13.51]) by out01.mta.xmission.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1kBgBY-009G4m-Lq; Fri, 28 Aug 2020 09:21:00 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in01.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.87) (envelope-from ) id 1kBgBX-0005hi-Pt; Fri, 28 Aug 2020 09:21:00 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Linux Containers Date: Fri, 28 Aug 2020 10:17:16 -0500 Message-ID: <87zh6eiyv7.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 X-XM-SPF: eid=1kBgBX-0005hi-Pt; ; ; mid=<87zh6eiyv7.fsf@x220.int.ebiederm.org>; ; ; hst=in01.mta.xmission.com; ; ; ip=68.227.160.95; ; ; frm=ebiederm@xmission.com; ; ; spf=neutral X-XM-AID: U2FsdGVkX1+Zc+8qmx0/P89xd8MH2SeFwyZD3o8jJlM= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Use cases for multiple uid mapping? X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Cc: Christian Brauner X-BeenThere: containers@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux Containers List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: containers-bounces@lists.linux-foundation.org Sender: "Containers" We had a discussion in the hackroom at LPC talking about use cases for a shiftfs style setup where there are different mappings of uids to disk. In the discussion we had a couple of ideas of kernel developments we should look at that address some of these. - Fix rlimits in user namespaces (This potentially allows multiple containers to run with the same userids simplifying the mapping problem). - Look at extending kuid_t to 64bits and using the highbits to implement uids that are private to user namespaces and don't map out. - Look at ways for allowing setgroups unprivileged. Together this has the potential that the existing uid & gid mappings will be able to function the same as the proposed fusid mappings. Fingers crossed. I had some problems with audio and a lot of people were talking quickly. So I did not manage to capture everyone's use cases. And I definitely was not able to see how everyone's use cases interacted with the changes we are looking at. I know for certain I missed Serge's usecase (apologies). Can people follow up to this and report their use cases? There are some real challenges and I would like to see if we can solve them, while avoiding scary problems like changing uids on write. Eric _______________________________________________ Containers mailing list Containers@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/containers