From patchwork Fri May 25 07:49:15 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joel Reardon X-Patchwork-Id: 161250 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:4978:20e::2]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id D3475B6EEC for ; Fri, 25 May 2012 17:51:07 +1000 (EST) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1SXpH0-00044C-9E; Fri, 25 May 2012 07:49:22 +0000 Received: from [78.46.68.141] (helo=eristoteles.iwoars.net) by merlin.infradead.org with smtp (Exim 4.76 #1 (Red Hat Linux)) id 1SXpGw-00043e-9t for linux-mtd@lists.infradead.org; Fri, 25 May 2012 07:49:20 +0000 Received: (qmail 1651 invoked by uid 5144); 25 May 2012 09:49:15 +0200 Received: from localhost (sendmail-bs@127.0.0.1) by localhost with SMTP; 25 May 2012 09:49:15 +0200 Date: Fri, 25 May 2012 09:49:15 +0200 (CEST) From: Joel Reardon X-X-Sender: joel@eristoteles.iwoars.net To: Artem Bityutskiy Subject: Re: [PATCH] UBIFS: introduce struct ubifs_keymap In-Reply-To: <1337769818.2483.202.camel@sauron.fi.intel.com> Message-ID: References: <1337769818.2483.202.camel@sauron.fi.intel.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 X-Spam-Note: CRM114 invocation failed X-Spam-Score: -1.1 (-) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-1.1 points) pts rule name description ---- ---------------------- -------------------------------------------------- -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] 0.8 RDNS_NONE Delivered to internal network by a host with no rDNS Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-mtd-bounces@lists.infradead.org Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org This patch introduces struct ubifs_keymap, the entity responsible for key generation, distribution, and lifetime management for ubifs's secure deletion. In addition to the struct's (partial) definition, it is added as a field to ubifs_info. The alloc routines are provided. More fields and functions will come in following patches. This is tested using local unit tests for the functions: alloc, and checking couple/decouple is sound. UBIFS integck is also run to ensure UBIFS is not effected. Signed-off-by: Joel Reardon --- fs/ubifs/Makefile | 2 +- fs/ubifs/keymap.c | 104 +++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/ubifs/ubifs.h | 6 +++ 3 files changed, 111 insertions(+), 1 deletions(-) create mode 100644 fs/ubifs/keymap.c diff --git a/fs/ubifs/Makefile b/fs/ubifs/Makefile index 2c6f0cb..881ce27 100644 --- a/fs/ubifs/Makefile +++ b/fs/ubifs/Makefile @@ -1,6 +1,6 @@ obj-$(CONFIG_UBIFS_FS) += ubifs.o -ubifs-y += shrinker.o journal.o file.o dir.o super.o sb.o io.o +ubifs-y += shrinker.o journal.o file.o dir.o super.o sb.o io.o keymap.o ubifs-y += tnc.o master.o scan.o replay.o log.o commit.o gc.o orphan.o ubifs-y += budget.o find.o tnc_commit.o compress.o lpt.o lprops.o ubifs-y += recovery.o ioctl.o lpt_commit.o tnc_misc.o xattr.o debug.o diff --git a/fs/ubifs/keymap.c b/fs/ubifs/keymap.c new file mode 100644 index 0000000..6f812c5 --- /dev/null +++ b/fs/ubifs/keymap.c @@ -0,0 +1,104 @@ +/* + * This file is part of UBIFS. + * + * Copyright (C) 2012 Joel Reardon + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., 51 + * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + * + * Authors: Joel Reardon + */ + +/* + * The file implements the key storage, assignment, and deletion for UBIFS's + * secure deletion enhancement. For more information, read + * Documentation/filesystems/ubifsec.txt + */ + +#include +#include "ubifs.h" + +/** + * struct ubifs_keymap - UBIFS key map. + * @key_size: size of a key in bytes + * @keys_per_leb: number of keys per KSA LEB + * @ksa_size: number of LEBS in the KSA + * @ksa_first: the first LEB belonging to the KSA + * @unused: the number of unused keys in the system + * @deleted: the number of deleted keys in the system. + * + * This manages the use of keys in UBIFS. There is only + * instance of the keymap for the UBIFS main context. Its main purpose is to + * be aware of which LEBs belong to the KSA, how the KSA is divided into + * ranges, the state for each key, and mutexes to ensure thread safety. + */ +struct ubifs_keymap { + unsigned int key_size; + unsigned int keys_per_leb; + unsigned int ksa_size; + unsigned int ksa_first; + long long unused; + long long deleted; +}; + +/** + * ksa_pos_decouple - convert a ksa_pos to ksa_leb and offset + * @ksa_pos: the key's position in the KSA + * @ksa_leb: gets the KSA LEB number for the key position + * @ksa_offs: gets the KSA LEB offset for the key position + * + * This function converts a 64-bit KSA position into the KSA LEB number and + * offset so it can be looked up. + */ +static void ksa_pos_decouple(const long long ksa_pos, + int *ksa_leb, int *ksa_offs) +{ + *ksa_offs = 0xffffffff & ksa_pos; + *ksa_leb = 0xffffffff & (ksa_pos >> 32); +} + +/** + * ksa_pos_couple - convert a ksa_leb and offset to ksa_pos + * @ksa_leb: gets the KSA LEB number for the key position + * @ksa_offs: gets the KSA LEB offset for the key position + * + * This function converts the LEB number and offset for a key into the 64-bit + * key position value. + */ +static long long ksa_pos_couple(int ksa_leb, int ksa_offs) +{ + return ((long long)ksa_leb << 32) + ksa_offs; +} + +/** + * keymap_init - construct and initialize a struct keymap + * @c: the ubifs info context to put the keymap into + * + * This function allocates a keymap data structure and initializes its fields. + * The ubifs_info context @c is passed as a parameter and its @km field is set + * to the keymap that is preprared by this function. If memory cannot be + * allocated, it returns -ENOMEM. Otherwise it returns 0. + */ +int keymap_init(struct ubifs_info *c) +{ + struct ubifs_keymap *km; + + c->km = km = kzalloc(sizeof(struct ubifs_keymap), GFP_NOFS); + if (!km) + return -ENOMEM; + + km->key_size = UBIFS_CRYPTO_KEYSIZE; + km->keys_per_leb = c->leb_size / km->key_size; + + return 0; +} diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h index 74f458c..6912f34 100644 --- a/fs/ubifs/ubifs.h +++ b/fs/ubifs/ubifs.h @@ -978,6 +978,7 @@ struct ubifs_budg_info { }; struct ubifs_debug_info; +struct ubifs_keymap; /** * struct ubifs_info - UBIFS file-system description data structure @@ -1224,6 +1225,7 @@ struct ubifs_debug_info; * @mount_opts: UBIFS-specific mount options * * @dbg: debugging-related information + * @keymap: cryptographic key store for secure deletion */ struct ubifs_info { struct super_block *vfs_sb; @@ -1452,6 +1454,7 @@ struct ubifs_info { struct ubifs_mount_opts mount_opts; struct ubifs_debug_info *dbg; + struct ubifs_keymap *km; }; extern struct list_head ubifs_infos; @@ -1780,6 +1783,9 @@ void ubifs_compress(const void *in_buf, int in_len, void *out_buf, int *out_len, int ubifs_decompress(void *buf, int len, void *out, int *out_len, int compr_type, void *crypto_key); +/* keymap.c */ +int keymap_init(struct ubifs_info *c); + #include "debug.h" #include "misc.h" #include "key.h"