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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 36E89C00449 for ; Wed, 3 Oct 2018 22:51:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D743A2147C for ; Wed, 3 Oct 2018 22:51:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D743A2147C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=vivier.eu Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726511AbeJDFl3 (ORCPT ); Thu, 4 Oct 2018 01:41:29 -0400 Received: from mout.kundenserver.de ([212.227.126.131]:38611 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725723AbeJDFl3 (ORCPT ); Thu, 4 Oct 2018 01:41:29 -0400 Received: from localhost.localdomain ([78.238.229.36]) by mrelayeu.kundenserver.de (mreue009 [212.227.15.167]) with ESMTPSA (Nemesis) id 1M8hMn-1g3B8d02Kn-004ijJ; Thu, 04 Oct 2018 00:50:34 +0200 Received: from localhost.localdomain ([78.238.229.36]) by mrelayeu.kundenserver.de (mreue009 [212.227.15.167]) with ESMTPSA (Nemesis) id 1M8hMn-1g3B8d02Kn-004ijJ; Thu, 04 Oct 2018 00:50:34 +0200 From: Laurent Vivier To: linux-kernel@vger.kernel.org Cc: Dmitry Safonov , Alexander Viro , Jann Horn , linux-fsdevel@vger.kernel.org, James Bottomley , Andrei Vagin , containers@lists.linux-foundation.org, Eric Biederman , linux-api@vger.kernel.org, Laurent Vivier Subject: [RFC v3 0/1] ns: introduce binfmt_misc namespace Date: Thu, 4 Oct 2018 00:50:21 +0200 Message-Id: <20181003225022.32033-1-laurent@vivier.eu> X-Mailer: git-send-email 2.17.1 X-Provags-ID: V03:K1:Itdnkg1CbJ89sYCoqiKuXvDDz+lmArH/O9tmqMBNe87MnWNBQ60 4YGX16RHE+iANIlPPOIwwSLxGnm38Z/v8vH5Eh/rhT5ZV4PQiR5cpbeYYTt3tQ1SY06u9Rp M3ds6YP0Xz73STW7e/8owzAdcvT91QbCo5onkMWesARcXmrf4YSSVXOlg1M2tpEb6ot6YCP 2lXr07xhpm915FTaVTwOw== X-UI-Out-Filterresults: notjunk:1;V01:K0:3z+Cxg6sXT8=:76nfUU6ZoUEhzwHqzm4z6F hV3mchLKYKEM7gCZlsXUJNsD+u+Wo14P8J1vGYjhihFOMtRSb32suUnUi1uyGkgeFklDHokX4 bATxfoXV87S5gUaXstCCt1HhaO8Gu+ogvqmWAC93pLoeW8rh0nj8QUsrQNxad5yLtjdpT193c NYSiOk/cMzvdZNM4K7RDRLOlTo1MdjgV9M5x9wanqGff5GHgb93mNkPbxp3+koxIrITD7Bhn/ F0Ab/3geb1Rj/8qWmXX/4XyHmpCSvQzANAzdRx/sIgHJ7VSTlEm2QOfw35RkjHyLd9NnC/rcj UoIJZAm2hFHAwDKRtwQfmwPiZ+m7GEcnq18BqarDP1e4sF0Smvl7XwwWQYs1SFLwfGSAYIUOd jPkn3XoHVcNLbtM1VDOtSji44DeRHP11hyjOvR0RKLODrjnP1fqmgWvYC/JW3mh65A28gnRbi 0XgfbMRNGD5uhBVhiXDNZBrm9M5T3alZmHUUVeTfz4B5rSJ92bLnrkJsx4eXao27eX73TlYJM dTwjQ2UjnPrP41hrxkF+N2bj0j6EzCbdbq9t7eGuEQqiFZRlkAJA9nfPdbyQ/JX82JkIw9fpa tMJ+rdjV8WNm0S7S+kOmlJ4Z3onoNhbBzYSy0NWR9u6Okb9OE0FvY5UXIHEG1e86TvlDX0BmA GtJ/Mesv3Ll7cfZVLl8XSvT9fC2+Y5uxjAHIP3/WB7cN/AsxAxy75J9sG9RtiXq+vwic= Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org v3: create a structure to store binfmt_misc data, add a pointer to this structure in the user_namespace structure, in init_user_ns structure this pointer points to an init_binfmt_ns structure. And all new user namespaces point to this init structure. A new binfmt namespace structure is allocated if the binfmt_misc filesystem is mounted in a user namespace that is not the initial one but its binfmt namespace pointer points to the initial one. add override_creds()/revert_creds() around open_exec() in bm_register_write() v2: no new namespace, binfmt_misc data are now part of the mount namespace I put this in mount namespace instead of user namespace because the mount namespace is already needed and I don't want to force to have the user namespace for that. As this is a filesystem, it seems logic to have it here. This allows to define a new interpreter for each new container. But the main goal is to be able to chroot to a directory using a binfmt_misc interpreter without being root. I have a modified version of unshare at: git@github.com:vivier/util-linux.git branch unshare-chroot with some new options to unshare binfmt_misc namespace and to chroot to a directory. If you have a directory /chroot/powerpc/jessie containing debian for powerpc binaries and a qemu-ppc interpreter, you can do for instance: $ uname -a Linux fedora28-wor-2 4.19.0-rc5+ #18 SMP Mon Oct 1 00:32:34 CEST 2018 x86_64 x86_64 x86_64 GNU/Linux $ ./unshare --map-root-user --fork --pid \ --load-interp ":qemu-ppc:M::\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x14:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/qemu-ppc:OC" \ --root=/chroot/powerpc/jessie /bin/bash -l # uname -a Linux fedora28-wor-2 4.19.0-rc5+ #18 SMP Mon Oct 1 00:32:34 CEST 2018 ppc GNU/Linux # id uid=0(root) gid=0(root) groups=0(root),65534(nogroup) # ls -l total 5940 drwxr-xr-x. 2 nobody nogroup 4096 Aug 12 00:58 bin drwxr-xr-x. 2 nobody nogroup 4096 Jun 17 20:26 boot drwxr-xr-x. 4 nobody nogroup 4096 Aug 12 00:08 dev drwxr-xr-x. 42 nobody nogroup 4096 Sep 28 07:25 etc drwxr-xr-x. 3 nobody nogroup 4096 Sep 28 07:25 home drwxr-xr-x. 9 nobody nogroup 4096 Aug 12 00:58 lib drwxr-xr-x. 2 nobody nogroup 4096 Aug 12 00:08 media drwxr-xr-x. 2 nobody nogroup 4096 Aug 12 00:08 mnt drwxr-xr-x. 3 nobody nogroup 4096 Aug 12 13:09 opt dr-xr-xr-x. 143 nobody nogroup 0 Sep 30 23:02 proc -rwxr-xr-x. 1 nobody nogroup 6009712 Sep 28 07:22 qemu-ppc drwx------. 3 nobody nogroup 4096 Aug 12 12:54 root drwxr-xr-x. 3 nobody nogroup 4096 Aug 12 00:08 run drwxr-xr-x. 2 nobody nogroup 4096 Aug 12 00:58 sbin drwxr-xr-x. 2 nobody nogroup 4096 Aug 12 00:08 srv drwxr-xr-x. 2 nobody nogroup 4096 Apr 6 2015 sys drwxrwxrwt. 2 nobody nogroup 4096 Sep 28 10:31 tmp drwxr-xr-x. 10 nobody nogroup 4096 Aug 12 00:08 usr drwxr-xr-x. 11 nobody nogroup 4096 Aug 12 00:08 var If you want to use the qemu binary provided by your distro, you can use --load-interp ":qemu-ppc:M::\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x14:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/bin/qemu-ppc-static:OCF" With the 'F' flag, qemu-ppc-static will be then loaded from the main root filesystem before switching to the chroot. Laurent Vivier (1): ns: add binfmt_misc to the user namespace fs/binfmt_misc.c | 85 +++++++++++++++++++++++----------- include/linux/user_namespace.h | 15 ++++++ kernel/user.c | 14 ++++++ kernel/user_namespace.c | 9 ++++ 4 files changed, 95 insertions(+), 28 deletions(-) -- 2.17.1