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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 F4164C55189 for ; Thu, 23 Apr 2020 01:37:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D8C842074F for ; Thu, 23 Apr 2020 01:37:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725961AbgDWBh5 (ORCPT ); Wed, 22 Apr 2020 21:37:57 -0400 Received: from mail.hallyn.com ([178.63.66.53]:53220 "EHLO mail.hallyn.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725854AbgDWBh5 (ORCPT ); Wed, 22 Apr 2020 21:37:57 -0400 Received: by mail.hallyn.com (Postfix, from userid 1001) id 44E5B9D0; Wed, 22 Apr 2020 20:37:54 -0500 (CDT) Date: Wed, 22 Apr 2020 20:37:54 -0500 From: "Serge E. Hallyn" To: Christian Brauner Cc: Jens Axboe , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org, Jonathan Corbet , Serge Hallyn , "Rafael J. Wysocki" , Tejun Heo , "David S. Miller" , Saravana Kannan , Jan Kara , David Howells , Seth Forshee , David Rheinsberg , Tom Gundersen , Christian Kellner , Dmitry Vyukov , =?iso-8859-1?Q?St=E9phane?= Graber , linux-doc@vger.kernel.org, netdev@vger.kernel.org, Steve Barber , Dylan Reid , Filipe Brandenburger , Kees Cook , Benjamin Elder , Akihiro Suda Subject: Re: [PATCH v2 7/7] loopfs: only show devices in their correct instance Message-ID: <20200423013754.GC2982@mail.hallyn.com> References: <20200422145437.176057-1-christian.brauner@ubuntu.com> <20200422145437.176057-8-christian.brauner@ubuntu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200422145437.176057-8-christian.brauner@ubuntu.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-api-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Wed, Apr 22, 2020 at 04:54:37PM +0200, Christian Brauner wrote: > Since loopfs devices belong to a loopfs instance they have no business > polluting the host's devtmpfs mount and should not propagate out of the > namespace they belong to. > > Cc: Jens Axboe > Cc: Greg Kroah-Hartman > Signed-off-by: Christian Brauner Reviewed-by: Serge Hallyn > --- > /* v2 */ > unchanged > --- > drivers/base/devtmpfs.c | 4 ++-- > drivers/block/loop.c | 4 +++- > include/linux/device.h | 3 +++ > 3 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c > index c9017e0584c0..77371ceb88fa 100644 > --- a/drivers/base/devtmpfs.c > +++ b/drivers/base/devtmpfs.c > @@ -111,7 +111,7 @@ int devtmpfs_create_node(struct device *dev) > const char *tmp = NULL; > struct req req; > > - if (!thread) > + if (!thread || dev->no_devnode) > return 0; > > req.mode = 0; > @@ -138,7 +138,7 @@ int devtmpfs_delete_node(struct device *dev) > const char *tmp = NULL; > struct req req; > > - if (!thread) > + if (!thread || dev->no_devnode) > return 0; > > req.name = device_get_devnode(dev, NULL, NULL, NULL, &tmp); > diff --git a/drivers/block/loop.c b/drivers/block/loop.c > index 2dc53bad4b48..5548151b9f11 100644 > --- a/drivers/block/loop.c > +++ b/drivers/block/loop.c > @@ -2213,8 +2213,10 @@ static int loop_add(struct loop_device **l, int i, struct inode *inode) > disk->queue = lo->lo_queue; > sprintf(disk->disk_name, "loop%d", i); > #ifdef CONFIG_BLK_DEV_LOOPFS > - if (loopfs_i_sb(inode)) > + if (loopfs_i_sb(inode)) { > disk->user_ns = loopfs_i_sb(inode)->s_user_ns; > + disk_to_dev(disk)->no_devnode = true; > + } > #endif > > add_disk(disk); > diff --git a/include/linux/device.h b/include/linux/device.h > index ac8e37cd716a..c69ef1c5a0ef 100644 > --- a/include/linux/device.h > +++ b/include/linux/device.h > @@ -523,6 +523,8 @@ struct dev_links_info { > * sync_state() callback. > * @dma_coherent: this particular device is dma coherent, even if the > * architecture supports non-coherent devices. > + * @no_devnode: whether device nodes associated with this device are kept out > + * of devtmpfs (e.g. due to separate filesystem) > * > * At the lowest level, every device in a Linux system is represented by an > * instance of struct device. The device structure contains the information > @@ -622,6 +624,7 @@ struct device { > defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) > bool dma_coherent:1; > #endif > + bool no_devnode:1; > }; > > static inline struct device *kobj_to_dev(struct kobject *kobj) > -- > 2.26.1