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=-4.1 required=3.0 tests=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 CB6FDC35671 for ; Sat, 22 Feb 2020 05:39:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A3E42214DB for ; Sat, 22 Feb 2020 05:39:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582349948; bh=tstnNHhaIvRVX4ExQFdDOhN9ZstDOzAqulx7HPJbK8Q=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Xk882SxSNzsghvKQ+xrInqbuOlxOJe0juF62E0Y8xHB5Joa/ROSy+3oAzv7XiyNHL iByR5fPQjMQFo8J926CjeT3J8T6dUqmUpAGLKLWNNAMZecxR/k0C8fp/s+QrF0JWuf 9YpWthZ3oP44Ukxdb47TWWzQlzGwsNRlGIxg+bgM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726688AbgBVFjI (ORCPT ); Sat, 22 Feb 2020 00:39:08 -0500 Received: from mail.kernel.org ([198.145.29.99]:37930 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726053AbgBVFjH (ORCPT ); Sat, 22 Feb 2020 00:39:07 -0500 Received: from sol.localdomain (c-107-3-166-239.hsd1.ca.comcast.net [107.3.166.239]) (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 9F502208C3; Sat, 22 Feb 2020 05:39:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582349946; bh=tstnNHhaIvRVX4ExQFdDOhN9ZstDOzAqulx7HPJbK8Q=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nQfM6CCgx+pVqyEwP92qBWdLJjAuuh7iZeR3ncbtvvgsiun0gVfKr9vYHUxYAxjFP abj9rUQsDl68oqGY5yOTPK4sCVbNj+yNYvjFQxlcOdCuS2hCQWRqLguVjvPBGtdKF8 jOKekVc3QEjPSLZ+EsQDPvTSXf7tADwaIwl6OAh4= Date: Fri, 21 Feb 2020 21:39:05 -0800 From: Eric Biggers To: Satya Tangirala Cc: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-ext4@vger.kernel.org, Barani Muthukumaran , Kuohong Wang , Kim Boojin Subject: Re: [PATCH v7 7/9] fscrypt: add inline encryption support Message-ID: <20200222053905.GC848@sol.localdomain> References: <20200221115050.238976-1-satyat@google.com> <20200221115050.238976-8-satyat@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200221115050.238976-8-satyat@google.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, Feb 21, 2020 at 03:50:48AM -0800, Satya Tangirala wrote: > diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c > index 65cb09fa6ead..7c157130c16a 100644 > --- a/fs/crypto/keysetup.c > +++ b/fs/crypto/keysetup.c > @@ -19,6 +19,8 @@ struct fscrypt_mode fscrypt_modes[] = { > .cipher_str = "xts(aes)", > .keysize = 64, > .ivsize = 16, > + .blk_crypto_mode = BLK_ENCRYPTION_MODE_AES_256_XTS, > + .blk_crypto_dun_bytes_required = 8, > }, > [FSCRYPT_MODE_AES_256_CTS] = { > .friendly_name = "AES-256-CTS-CBC", > @@ -31,6 +33,8 @@ struct fscrypt_mode fscrypt_modes[] = { > .cipher_str = "essiv(cbc(aes),sha256)", > .keysize = 16, > .ivsize = 16, > + .blk_crypto_mode = BLK_ENCRYPTION_MODE_AES_128_CBC_ESSIV, > + .blk_crypto_dun_bytes_required = 8, > }, > [FSCRYPT_MODE_AES_128_CTS] = { > .friendly_name = "AES-128-CTS-CBC", > @@ -43,6 +47,8 @@ struct fscrypt_mode fscrypt_modes[] = { > .cipher_str = "adiantum(xchacha12,aes)", > .keysize = 32, > .ivsize = 32, > + .blk_crypto_mode = BLK_ENCRYPTION_MODE_ADIANTUM, > + .blk_crypto_dun_bytes_required = 24, > }, > }; The DUN bytes required is actually determined by the IV generation method too. Currently fscrypt has the following combinations: AES-256-XTS: 8 bytes AES-128-CBC-ESSIV: 8 bytes Adiantum without DIRECT_KEY: 8 bytes Adiantum with DIRECT_KEY: 24 bytes I.e., DIRECT_KEY is only allowed with Adiantum, but not required for it. So it's technically incorrect to always pass dun_bytes_required=24 for Adiantum. And it's conceivable that in the future we could add an fscrypt setting that uses AES-256-XTS with 16 IV bytes. Such a setting wouldn't be usable with UFS inline encryption, yet the existing AES-256-XTS settings still would. So, how about instead of putting .blk_crypto_dun_bytes_required in the crypto_mode table, using logic like: dun_bytes_required = 8; if (flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) dun_bytes_required += 16; > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 3cd4fe6b845e..2331ff0464b2 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -1370,6 +1370,7 @@ extern int send_sigurg(struct fown_struct *fown); > #define SB_NODIRATIME 2048 /* Do not update directory access times */ > #define SB_SILENT 32768 > #define SB_POSIXACL (1<<16) /* VFS does not apply the umask */ > +#define SB_INLINE_CRYPT (1<<17) /* inodes in SB use blk-crypto */ > #define SB_KERNMOUNT (1<<22) /* this is a kern_mount call */ > #define SB_I_VERSION (1<<23) /* Update inode I_version field */ > #define SB_LAZYTIME (1<<25) /* Update the on-disk [acm]times lazily */ This flag probably should be called "SB_INLINECRYPT" to match the mount option, which is "inlinecrypt" not "inline_crypt". Also, the addition of this flag, along with the update to show_sb_opts() in fs/proc_namespace.c which I think is needed, maybe should go in a separate patch whose subject is prefixed with "fs: " to make it clearer to reviewers that this part is a VFS-level change. - Eric