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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 8693DC64E8A for ; Wed, 2 Dec 2020 09:55:59 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (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 AB151206C0 for ; Wed, 2 Dec 2020 09:55:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AB151206C0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=containers-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 131ED870BE; Wed, 2 Dec 2020 09:55:58 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ZSN8zfAdYrBl; Wed, 2 Dec 2020 09:55:57 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by fraxinus.osuosl.org (Postfix) with ESMTP id 4E3EE870BA; Wed, 2 Dec 2020 09:55:57 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 33796C0859; Wed, 2 Dec 2020 09:55:57 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id B1A97C0052 for ; Wed, 2 Dec 2020 09:55:55 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id 9235B203A8 for ; Wed, 2 Dec 2020 09:55:55 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id MVkPiJ6MWZ2P for ; Wed, 2 Dec 2020 09:55:54 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by silver.osuosl.org (Postfix) with ESMTPS id CB28B203A7 for ; Wed, 2 Dec 2020 09:55:53 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 1049267373; Wed, 2 Dec 2020 10:55:48 +0100 (CET) Date: Wed, 2 Dec 2020 10:55:47 +0100 From: Christoph Hellwig To: Christian Brauner Subject: Re: [PATCH v3 04/38] fs: add mount_setattr() Message-ID: <20201202095547.GA6408@lst.de> References: <20201128213527.2669807-1-christian.brauner@ubuntu.com> <20201128213527.2669807-5-christian.brauner@ubuntu.com> <20201201104907.GD27730@lst.de> <20201202094218.ym5zqnulwz6gj6eo@wittgenstein> <20201202094751.GA6129@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201202094751.GA6129@lst.de> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: Lennart Poettering , Mimi Zohar , David Howells , Andreas Dilger , containers@lists.linux-foundation.org, Christoph Hellwig , Tycho Andersen , Paul Moore , Jonathan Corbet , smbarber@chromium.org, Christoph Hellwig , linux-ext4@vger.kernel.org, Mrunal Patel , Kees Cook , Arnd Bergmann , 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 , Stephen Smalley , fstests@vger.kernel.org, linux-security-module@vger.kernel.org, "Eric W. Biederman" , linux-api@vger.kernel.org, Casey Schaufler , Alban Crequy , linux-integrity@vger.kernel.org, Todd Kjos 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" On Wed, Dec 02, 2020 at 10:47:51AM +0100, Christoph Hellwig wrote: > On Wed, Dec 02, 2020 at 10:42:18AM +0100, Christian Brauner wrote: > > > > + if (upper_32_bits(attr->attr_set)) > > > > + return -EINVAL; > > > > + if (build_attr_flags(lower_32_bits(attr->attr_set), &kattr->attr_set)) > > > > + return -EINVAL; > > > > + > > > > + if (upper_32_bits(attr->attr_clr)) > > > > + return -EINVAL; > > > > + if (build_attr_flags(lower_32_bits(attr->attr_clr), &kattr->attr_clr)) > > > > + return -EINVAL; > > > > > > What is so magic about the upper and lower 32 bits? > > > > Nothing apart from the fact that they arent't currently valid. I can > > think about reworking these lines. Or do you already have a preferred > > way of doing this in mind? > > Just turn the attr_flags argument to build_attr_flags into a u64 and > the first sanity check there will catch all invalid flags, no matter > where they are places. That should also generate more efficient code. And while we're at it: the check for valid flags in the current code is a little weird, given that build_attr_flags checks for them, and but sys_fsmount also has its own slightly narrower checks. I think it might make sense to split the validity check out of build_attr_flags. E.g. something like: static unsigned int attr_flags_to_mnt_flags(u64 attr_flags) { unsigned int mnt_flags = 0; if (attr_flags & MOUNT_ATTR_RDONLY) mnt_flags |= MNT_READONLY; if (attr_flags & MOUNT_ATTR_NOSUID) mnt_flags |= MNT_NOSUID; if (attr_flags & MOUNT_ATTR_NODEV) mnt_flags |= MNT_NODEV; if (attr_flags & MOUNT_ATTR_NOEXEC) mnt_flags |= MNT_NOEXEC; if (attr_flags & MOUNT_ATTR_NODIRATIME) mnt_flags |= MNT_NODIRATIME; return mnt_flags; } #define MOUNT_SETATTR_VALID_FLAGS \ (MOUNT_ATTR_RDONLY | MOUNT_ATTR_NOSUID | MOUNT_ATTR_NODEV | \ MOUNT_ATTR_NOEXEC | MOUNT_ATTR__ATIME | MOUNT_ATTR_NODIRATIME | \ MOUNT_ATTR_IDMAP) static int build_mount_kattr(const struct mount_attr *attr, size_t usize, struct mount_kattr *kattr, unsigned int flags) { ... if ((attr->attr_set | attr->attr_clr) & ~MOUNT_SETATTR_VALID_FLAGS) return -EINVAL; kattr->attr_set = attr_flags_to_mnt_flags(attr->attr_set); kattr->attr_clr = attr_flags_to_mnt_flags(attr->attr_clr); ... } _______________________________________________ Containers mailing list Containers@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/containers