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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 674AAC2D0A3 for ; Tue, 3 Nov 2020 13:24:02 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BB79B20715 for ; Tue, 3 Nov 2020 13:24:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BB79B20715 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=tempfail smtp.mailfrom=linux-audit-bounces@redhat.com Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-491-f-JMe-0mNk-P4eDQbGJ8ZA-1; Tue, 03 Nov 2020 08:23:57 -0500 X-MC-Unique: f-JMe-0mNk-P4eDQbGJ8ZA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2BC21803F69; Tue, 3 Nov 2020 13:23:52 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 146A66EF73; Tue, 3 Nov 2020 13:23:52 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id E8C1C1826D3C; Tue, 3 Nov 2020 13:23:51 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 0A1Ek7ce013597 for ; Sun, 1 Nov 2020 09:46:07 -0500 Received: by smtp.corp.redhat.com (Postfix) id B9EB1200E214; Sun, 1 Nov 2020 14:46:07 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast05.extmail.prod.ext.rdu2.redhat.com [10.11.55.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B4C2C20244F7 for ; Sun, 1 Nov 2020 14:46:04 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6B5568D6324 for ; Sun, 1 Nov 2020 14:46:04 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-182-7EIxutiPPI2DWyfnxXzAIw-1; Sun, 01 Nov 2020 09:46:01 -0500 X-MC-Unique: 7EIxutiPPI2DWyfnxXzAIw-1 Received: from hch by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kZEc4-0006Y5-Kp; Sun, 01 Nov 2020 14:45:44 +0000 Date: Sun, 1 Nov 2020 14:45:44 +0000 From: Christoph Hellwig To: Christian Brauner Subject: Re: [PATCH 05/34] fs: introduce MOUNT_ATTR_IDMAP Message-ID: <20201101144544.GC23378@infradead.org> References: <20201029003252.2128653-1-christian.brauner@ubuntu.com> <20201029003252.2128653-6-christian.brauner@ubuntu.com> MIME-Version: 1.0 In-Reply-To: <20201029003252.2128653-6-christian.brauner@ubuntu.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-loop: linux-audit@redhat.com X-Mailman-Approved-At: Tue, 03 Nov 2020 08:23:38 -0500 Cc: Phil Estes , Lennart Poettering , Amir Goldstein , Mimi Zohar , David Howells , Andreas Dilger , containers@lists.linux-foundation.org, Tycho Andersen , Miklos Szeredi , James Morris , smbarber@chromium.org, Christoph Hellwig , linux-ext4@vger.kernel.org, Mrunal Patel , Serge Hallyn , Arnd Bergmann , Jann Horn , selinux@vger.kernel.org, Josh Triplett , linux-fsdevel@vger.kernel.org, Aleksa Sarai , Alexander Viro , Andy Lutomirski , OGAWA Hirofumi , Geoffrey Thomas , James Bottomley , John Johansen , Theodore Tso , Seth Forshee , Dmitry Kasatkin , Jonathan Corbet , linux-unionfs@vger.kernel.org, linux-security-module@vger.kernel.org, linux-audit@redhat.com, "Eric W. Biederman" , linux-api@vger.kernel.org, Alban Crequy , linux-integrity@vger.kernel.org, St??phane Graber , Todd Kjos X-BeenThere: linux-audit@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: Linux Audit Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-audit-bounces@redhat.com Errors-To: linux-audit-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=linux-audit-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Thu, Oct 29, 2020 at 01:32:23AM +0100, Christian Brauner wrote: > Introduce a new mount bind mount property to allow idmapping mounts. The > MOUNT_ATTR_IDMAP flag can be set via the new mount_setattr() syscall > together with a file descriptor referring to a user namespace. Shouldn't this go to the end of the series once all the infrastructure is in place? > +config IDMAP_MOUNTS > + bool "Support id mappings per mount" > + default n n is the default default. But why do we need a config option here anyway? > +#ifdef CONFIG_IDMAP_MOUNTS > + if (kattr->attr_set & MNT_IDMAPPED) { > + struct user_namespace *user_ns; > + struct vfsmount *vmnt; All the code here looks like it should go into a helper. > + struct user_namespace *user_ns = READ_ONCE(m->mnt.mnt_user_ns); > + WRITE_ONCE(m->mnt.mnt_user_ns, get_user_ns(kattr->userns)); More unreadable long lines. > + if (attr->attr_set & MOUNT_ATTR_IDMAP) { > + struct ns_common *ns; > + struct user_namespace *user_ns; > + struct file *file; > + > + file = fget(attr->userns); The code here looks like another candidate for a self contained helper. > + > +static inline struct user_namespace *mnt_user_ns(const struct vfsmount *mnt) > +{ > +#ifdef CONFIG_IDMAP_MOUNTS > + return READ_ONCE(mnt->mnt_user_ns); > +#else > + return &init_user_ns; > +#endif How is the READ_ONCE on a pointer going to work? -- Linux-audit mailing list Linux-audit@redhat.com https://www.redhat.com/mailman/listinfo/linux-audit