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=-7.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,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 E0554C2D0E1 for ; Wed, 9 Sep 2020 17:19:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8F72C2166E for ; Wed, 9 Sep 2020 17:19:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599671975; bh=pHgbv20ycv59bJxqyA+U6rPfrqeKv2GN7dRnJhn0ljo=; h=Subject:From:To:Cc:Date:In-Reply-To:References:List-ID:From; b=Ym/L1S+jastPMZ1V09/vukDOfEwDHwI9HdMbdKUQhei3GQQWswddBkL9meGnv/VI3 iuwQEsy2HH4vsTmVJnStTQe2c1V2iIlhfss+Uz2E+5EvrjFrUawjvNe8E/hZ4kYM2P mCfFx/GZDgvx5xOKDiO6NF5RiGNoMnw3H753Es00= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731148AbgIIRTe (ORCPT ); Wed, 9 Sep 2020 13:19:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:44548 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730157AbgIIRT3 (ORCPT ); Wed, 9 Sep 2020 13:19:29 -0400 Received: from tleilax.poochiereds.net (68-20-15-154.lightspeed.rlghnc.sbcglobal.net [68.20.15.154]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9C117206D4; Wed, 9 Sep 2020 17:19:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599671969; bh=pHgbv20ycv59bJxqyA+U6rPfrqeKv2GN7dRnJhn0ljo=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=MDnax6gU6Si9NOHpgs7J+70cygHHgY4F/fMGO/w7q5zAOd90Dawc9hb6vSK1Um1GO h2kPLisicOh7c7vWcRlP4enJ0CF+2zzHWuM8MhNyydhPku9BjCWx/XSJ8m2a9ASGN0 86YRUm3xEAeWYOa4dmwMT+fg1/LSUfT8SH0m9JL8= Message-ID: <3e56484187b739cfdfbfbc699ecc82800cbaa92c.camel@kernel.org> Subject: Re: [RFC PATCH v2 12/18] ceph: set S_ENCRYPTED bit if new inode has encryption.ctx xattr From: Jeff Layton To: Eric Biggers Cc: ceph-devel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-fscrypt@vger.kernel.org Date: Wed, 09 Sep 2020 13:19:27 -0400 In-Reply-To: <20200909163352.GC828@sol.localdomain> References: <20200904160537.76663-1-jlayton@kernel.org> <20200904160537.76663-13-jlayton@kernel.org> <20200908045737.GK68127@sol.localdomain> <20200909163352.GC828@sol.localdomain> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.36.5 (3.36.5-1.fc32) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: ceph-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org On Wed, 2020-09-09 at 09:33 -0700, Eric Biggers wrote: > On Wed, Sep 09, 2020 at 11:53:35AM -0400, Jeff Layton wrote: > > > > diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c > > > > index 651148194316..c1c1fe2547f9 100644 > > > > --- a/fs/ceph/inode.c > > > > +++ b/fs/ceph/inode.c > > > > @@ -964,6 +964,10 @@ int ceph_fill_inode(struct inode *inode, struct page *locked_page, > > > > ceph_forget_all_cached_acls(inode); > > > > ceph_security_invalidate_secctx(inode); > > > > xattr_blob = NULL; > > > > + if ((inode->i_state & I_NEW) && > > > > + (DUMMY_ENCRYPTION_ENABLED(mdsc->fsc) || > > > > + ceph_inode_has_xattr(ci, CEPH_XATTR_NAME_ENCRYPTION_CONTEXT))) > > > > + inode_set_flags(inode, S_ENCRYPTED, S_ENCRYPTED); > > > > > > The check for DUMMY_ENCRYPTION_ENABLED() here is wrong and should be removed. > > > When the filesystem is mounted with test_dummy_encryption, there may be > > > unencrypted inodes already on-disk. Those shouldn't get S_ENCRYPTED set. > > > test_dummy_encryption does add some special handling for unencrypted > > > directories, but that doesn't require S_ENCRYPTED to be set on them. > > > > > > > I've been working through your comments. Symlinks work now, as long as I > > use the fscrypt utility instead of test_dummy_encryption. > > > > When I remove that condition above, then test_dummy_encryption no longer > > works. I think I must be missing some context in how > > test_dummy_encryption is supposed to be used. > > > > Suppose I mount a ceph filesystem with -o test_dummy_encryption. The > > root inode of the fs is instantiated by going through here, but it's not > > marked with S_ENCRYPTED because the root has no context. > > > > How will descendant dentries end up encrypted if this one is not marked > > as such? > > See fscrypt_prepare_new_inode() (or in current mainline, the logic in > __ext4_new_inode() and f2fs_may_encrypt()). Encryption gets inherited if: > > IS_ENCRYPTED(dir) || fscrypt_get_dummy_context(dir->i_sb) != NULL > > instead of just: > > IS_ENCRYPTED(dir) > > Note that this specifically refers to encryption being *inherited*. > If !IS_ENCRYPTED(dir), then the directory itself remains unencrypted --- > that means that the filenames are in the directory aren't encrypted, even if > they name encrypted files/directories/symlinks. > Ok, I think I get it, but it is a little weird. I would have thought that test_dummy_encryption would just replace the usage of whatever's in the xattr with the per-sb one (or maybe only when one doesn't exist). This is a bit different though, in that the dummy context only comes into play with newly created inodes. So, if I mount an empty subdirectory using test_dummy_encryption, you can't encrypt the names at the root. I guess that's sort of like how it works with "regular" contexts too, and that prevents someone clobbering old data mistakenly. Thanks for the explanation! -- Jeff Layton