Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751835AbcCKSu1 (ORCPT ); Fri, 11 Mar 2016 13:50:27 -0500 Received: from mail.kernel.org ([198.145.29.136]:58788 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750733AbcCKSuZ (ORCPT ); Fri, 11 Mar 2016 13:50:25 -0500 Date: Fri, 11 Mar 2016 10:50:20 -0800 From: Jaegeuk Kim To: Dan Williams Cc: Randy Dunlap , Linux Kernel Mailing List , linux-fsdevel , linux-f2fs-devel@lists.sourceforge.net, "Theodore Ts'o" Subject: Re: [PATCH 01/10] fs crypto: add basic definitions for per-file encryption Message-ID: <20160311185020.GA62857@jaegeuk.gateway> References: <1456428368-41527-1-git-send-email-jaegeuk@kernel.org> <1456428368-41527-2-git-send-email-jaegeuk@kernel.org> <56D3DA02.4010705@infradead.org> <20160301013536.GA60850@jaegeuk.hsd1.ca.comcast.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5144 Lines: 143 Hi Dan, On Thu, Mar 10, 2016 at 09:00:25PM -0800, Dan Williams wrote: > On Mon, Feb 29, 2016 at 5:35 PM, Jaegeuk Kim wrote: > > On Sun, Feb 28, 2016 at 09:41:22PM -0800, Randy Dunlap wrote: > >> On 02/25/16 11:25, Jaegeuk Kim wrote: > >> > This patch adds definitions for per-file encryption used by ext4 and f2fs. > >> > > >> > Signed-off-by: Jaegeuk Kim > >> > --- > >> > include/linux/fs.h | 8 ++ > >> > include/linux/fscrypto.h | 239 +++++++++++++++++++++++++++++++++++++++++++++++ > >> > include/uapi/linux/fs.h | 18 ++++ > >> > 3 files changed, 265 insertions(+) > >> > create mode 100644 include/linux/fscrypto.h > >> > > >> > diff --git a/include/linux/fs.h b/include/linux/fs.h > >> > index ae68100..d8f57cf 100644 > >> > --- a/include/linux/fs.h > >> > +++ b/include/linux/fs.h > >> > @@ -53,6 +53,8 @@ struct swap_info_struct; > >> > struct seq_file; > >> > struct workqueue_struct; > >> > struct iov_iter; > >> > +struct fscrypt_info; > >> > +struct fscrypt_operations; > >> > > >> > extern void __init inode_init(void); > >> > extern void __init inode_init_early(void); > >> > @@ -678,6 +680,10 @@ struct inode { > >> > struct hlist_head i_fsnotify_marks; > >> > #endif > >> > > >> > +#ifdef CONFIG_FS_ENCRYPTION > >> > + struct fscrypt_info *i_crypt_info; > >> > +#endif > >> > + > >> > void *i_private; /* fs or device private pointer */ > >> > }; > >> > > >> > @@ -1323,6 +1329,8 @@ struct super_block { > >> > #endif > >> > const struct xattr_handler **s_xattr; > >> > > >> > + const struct fscrypt_operations *s_cop; > >> > + > >> > struct hlist_bl_head s_anon; /* anonymous dentries for (nfs) exporting */ > >> > struct list_head s_mounts; /* list of mounts; _not_ for fs use */ > >> > struct block_device *s_bdev; > >> > diff --git a/include/linux/fscrypto.h b/include/linux/fscrypto.h > >> > new file mode 100644 > >> > index 0000000..b0aed92 > >> > --- /dev/null > >> > +++ b/include/linux/fscrypto.h > >> > @@ -0,0 +1,239 @@ > >> > +/* > >> > + * General per-file encryption definition > >> > + * > >> > + * Copyright (C) 2015, Google, Inc. > >> > + * > >> > + * Written by Michael Halcrow, 2015. > >> > + * Modified by Jaegeuk Kim, 2015. > >> > + */ > >> > + > >> > +#ifndef _LINUX_FSCRYPTO_H > >> > +#define _LINUX_FSCRYPTO_H > >> > + > >> > +#include > >> > +#include > >> > +#include > >> > +#include > >> > +#include > >> > +#include > >> > + > >> > +#define FS_KEY_DERIVATION_NONCE_SIZE 16 > >> > +#define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1 > >> > + > >> > +#define FS_POLICY_FLAGS_PAD_4 0x00 > >> > +#define FS_POLICY_FLAGS_PAD_8 0x01 > >> > +#define FS_POLICY_FLAGS_PAD_16 0x02 > >> > +#define FS_POLICY_FLAGS_PAD_32 0x03 > >> > +#define FS_POLICY_FLAGS_PAD_MASK 0x03 > >> > +#define FS_POLICY_FLAGS_VALID 0x03 > >> > + > >> > +/* Encryption algorithms */ > >> > +#define FS_ENCRYPTION_MODE_INVALID 0 > >> > +#define FS_ENCRYPTION_MODE_AES_256_XTS 1 > >> > +#define FS_ENCRYPTION_MODE_AES_256_GCM 2 > >> > +#define FS_ENCRYPTION_MODE_AES_256_CBC 3 > >> > +#define FS_ENCRYPTION_MODE_AES_256_CTS 4 > >> > + > >> > +/** > >> > + * Encryption context for inode > >> > + * > >> > + * Protector format: > >> > + * 1 byte: Protector format (1 = this version) > >> > + * 1 byte: File contents encryption mode > >> > + * 1 byte: File names encryption mode > >> > + * 1 byte: Flags > >> > + * 8 bytes: Master Key descriptor > >> > + * 16 bytes: Encryption Key derivation nonce > >> > + */ > >> > +struct fscrypt_context { > >> > + char format; > >> > + char contents_encryption_mode; > >> > + char filenames_encryption_mode; > >> > + char flags; > >> > + char master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE]; > >> > + char nonce[FS_KEY_DERIVATION_NONCE_SIZE]; > >> > >> how about u8 instead of char? > > > > It seems that it needs to user u8 instead of char for other variables as well. > > I'll take a look at all the usages. > > I think it needs to be __u8 otherwise I get this in a userspace program: > > In file included from test/blk_namespaces.c:17:0: > /usr/include/linux/fs.h:256:2: error: unknown type name ‘u8’ > u8 version; > ^ > /usr/include/linux/fs.h:257:2: error: unknown type name ‘u8’ > u8 contents_encryption_mode; > ^ > /usr/include/linux/fs.h:258:2: error: unknown type name ‘u8’ > u8 filenames_encryption_mode; > ^ > /usr/include/linux/fs.h:259:2: error: unknown type name ‘u8’ > u8 flags; > ^ > /usr/include/linux/fs.h:260:2: error: unknown type name ‘u8’ > u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE]; > ^ I realized that it needs to use __u8 as an exportable data type which can be seen by user-space programs. So, IMO, only fscrypt_policy should be exportable, and other structures need to use u8. Let me know, if I'm missing something. Thanks,