From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Theodore Ts'o" Subject: Re: [PATCH v2 4/5] fscrypt: only set dentry_operations on ciphertext dentries Date: Wed, 17 Apr 2019 10:07:01 -0400 Message-ID: <20190417140701.GD4686@mit.edu> References: <20190320183913.12686-1-ebiggers@kernel.org> <20190320183913.12686-5-ebiggers@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20190320183913.12686-5-ebiggers@kernel.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net To: Eric Biggers Cc: linux-unionfs@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fscrypt@vger.kernel.org, linux-mtd@lists.infradead.org, Sarthak Kukreti , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org List-Id: linux-unionfs@vger.kernel.org On Wed, Mar 20, 2019 at 11:39:12AM -0700, Eric Biggers wrote: > From: Eric Biggers > > Plaintext dentries are always valid, so only set fscrypt_d_ops on > ciphertext dentries. > > Besides marginally improved performance, this allows overlayfs to use an > fscrypt-encrypted upperdir, provided that all the following are true: > > (1) The fscrypt encryption key is placed in the keyring before > mounting overlayfs, and remains while the overlayfs is mounted. > > (2) The overlayfs workdir uses the same encryption policy. > > (3) No dentries for the ciphertext names of subdirectories have been > created in the upperdir or workdir yet. (Since otherwise > d_splice_alias() will reuse the old dentry with ->d_op set.) > > One potential use case is using an ephemeral encryption key to encrypt > all files created or changed by a container, so that they can be > securely erased ("crypto-shredded") after the container stops. > > Signed-off-by: Eric Biggers Looks good, applied. - Ted From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 17 Apr 2019 10:07:01 -0400 From: "Theodore Ts'o" Subject: Re: [PATCH v2 4/5] fscrypt: only set dentry_operations on ciphertext dentries Message-ID: <20190417140701.GD4686@mit.edu> References: <20190320183913.12686-1-ebiggers@kernel.org> <20190320183913.12686-5-ebiggers@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190320183913.12686-5-ebiggers@kernel.org> To: Eric Biggers Cc: linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mtd@lists.infradead.org, linux-unionfs@vger.kernel.org, Sarthak Kukreti , Gao Xiang List-ID: On Wed, Mar 20, 2019 at 11:39:12AM -0700, Eric Biggers wrote: > From: Eric Biggers > > Plaintext dentries are always valid, so only set fscrypt_d_ops on > ciphertext dentries. > > Besides marginally improved performance, this allows overlayfs to use an > fscrypt-encrypted upperdir, provided that all the following are true: > > (1) The fscrypt encryption key is placed in the keyring before > mounting overlayfs, and remains while the overlayfs is mounted. > > (2) The overlayfs workdir uses the same encryption policy. > > (3) No dentries for the ciphertext names of subdirectories have been > created in the upperdir or workdir yet. (Since otherwise > d_splice_alias() will reuse the old dentry with ->d_op set.) > > One potential use case is using an ephemeral encryption key to encrypt > all files created or changed by a container, so that they can be > securely erased ("crypto-shredded") after the container stops. > > Signed-off-by: Eric Biggers Looks good, applied. - Ted 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=-5.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_MUTT 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 D4132C282DA for ; Wed, 17 Apr 2019 14:07:14 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 A20D2206BA for ; Wed, 17 Apr 2019 14:07:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="gSW3OBye" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A20D2206BA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=mit.edu Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Hr7XoSL1468pMbcX5ycL2+W2vUtyxKvwLuYcMiExO20=; b=gSW3OByew/SPTM 4E7og6reO0idT2shj+6rrB8XzabAqTUBkgIGoZQNVuQyOInupryzF27kKtbDCXpYdNaJPupCql7X/ XKJBMTsquqJlL6d27X9dmB6VYBUiNzUoQF+q7Env4Snv3J2n83HBrYZdkw5u3aydPjq0XXbsmEQ3I wwmywKQdS/Po5k4+pUdcFkJdxnzfrU30F6n/Oyp5eoyFdvPRywFUyJ40c4m7AsUyE0GvRjel9kM4v j3M5hIiALV7raNRtepvGr3Arm+XU7gjAmJs8zF5c1EE8fFF0HzPvbA9YAtNAEzpTwKUtSzdOxa/w4 z8Gr6l+/so0DsoCfwrrA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hGlDU-0001Tl-PJ; Wed, 17 Apr 2019 14:07:12 +0000 Received: from outgoing-auth-1.mit.edu ([18.9.28.11] helo=outgoing.mit.edu) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hGlDR-0001T6-P1 for linux-mtd@lists.infradead.org; Wed, 17 Apr 2019 14:07:11 +0000 Received: from callcc.thunk.org (guestnat-104-133-0-109.corp.google.com [104.133.0.109] (may be forged)) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id x3HE72dN002538 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 17 Apr 2019 10:07:02 -0400 Received: by callcc.thunk.org (Postfix, from userid 15806) id 9F263420497; Wed, 17 Apr 2019 10:07:01 -0400 (EDT) Date: Wed, 17 Apr 2019 10:07:01 -0400 From: "Theodore Ts'o" To: Eric Biggers Subject: Re: [PATCH v2 4/5] fscrypt: only set dentry_operations on ciphertext dentries Message-ID: <20190417140701.GD4686@mit.edu> References: <20190320183913.12686-1-ebiggers@kernel.org> <20190320183913.12686-5-ebiggers@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190320183913.12686-5-ebiggers@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190417_070709_977757_51451B7F X-CRM114-Status: UNSURE ( 8.92 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Gao Xiang , linux-unionfs@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fscrypt@vger.kernel.org, linux-mtd@lists.infradead.org, Sarthak Kukreti , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Wed, Mar 20, 2019 at 11:39:12AM -0700, Eric Biggers wrote: > From: Eric Biggers > > Plaintext dentries are always valid, so only set fscrypt_d_ops on > ciphertext dentries. > > Besides marginally improved performance, this allows overlayfs to use an > fscrypt-encrypted upperdir, provided that all the following are true: > > (1) The fscrypt encryption key is placed in the keyring before > mounting overlayfs, and remains while the overlayfs is mounted. > > (2) The overlayfs workdir uses the same encryption policy. > > (3) No dentries for the ciphertext names of subdirectories have been > created in the upperdir or workdir yet. (Since otherwise > d_splice_alias() will reuse the old dentry with ->d_op set.) > > One potential use case is using an ephemeral encryption key to encrypt > all files created or changed by a container, so that they can be > securely erased ("crypto-shredded") after the container stops. > > Signed-off-by: Eric Biggers Looks good, applied. - Ted ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/