Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755612AbbFULWQ (ORCPT ); Sun, 21 Jun 2015 07:22:16 -0400 Received: from mail-wi0-f175.google.com ([209.85.212.175]:34380 "EHLO mail-wi0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754290AbbFULVs (ORCPT ); Sun, 21 Jun 2015 07:21:48 -0400 From: =?UTF-8?q?Pali=20Roh=C3=A1r?= To: Alasdair Kergon , Mike Snitzer , Neil Brown , "Rafael J. Wysocki" , Len Brown , Pavel Machek Cc: dm-devel@redhat.com, linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, =?UTF-8?q?Pali=20Roh=C3=A1r?= Subject: [PATCH v2 3/3] dm-crypt: Adds support for wiping key when doing suspend/hibernation Date: Sun, 21 Jun 2015 13:20:34 +0200 Message-Id: <1434885634-19895-4-git-send-email-pali.rohar@gmail.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1434885634-19895-1-git-send-email-pali.rohar@gmail.com> References: <1428254419-7334-1-git-send-email-pali.rohar@gmail.com> <1434885634-19895-1-git-send-email-pali.rohar@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8220 Lines: 284 This patch adds dm message commands and option strings to optionally wipe key from dm-crypt device before entering suspend or hibernate state. Before key is wiped dm device must be suspended. To prevent race conditions with I/O and userspace processes, wiping action must be called after processes are freezed. Otherwise userspace processes could start reading/writing to disk after dm device is suspened and freezing processes before suspend/hibernate action will fail. Signed-off-by: Pali Rohár --- Changes since v1: * Use "retain_on_hibernation" message instead "wipe_on_hibernation 0" * In crypt_suspend_and_wipe_key() check for errors and return status * In crypt_status() show also key_wipe_on_hibernation/key_wipe_on_suspend --- drivers/md/dm-crypt.c | 126 +++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 118 insertions(+), 8 deletions(-) diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c index 5503e43..f8536fb 100644 --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include #include @@ -31,6 +32,8 @@ #include +#include "dm.h" + #define DM_MSG_PREFIX "crypt" /* @@ -112,13 +115,18 @@ struct iv_tcw_private { * and encrypts / decrypts at the same time. */ enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID, - DM_CRYPT_SAME_CPU, DM_CRYPT_NO_OFFLOAD }; + DM_CRYPT_SAME_CPU, DM_CRYPT_NO_OFFLOAD, + DM_CRYPT_KEY_WIPE_ON_HIBERNATION, + DM_CRYPT_KEY_WIPE_ON_SUSPEND, +}; /* * The fields in here must be read only after initialization. */ struct crypt_config { struct dm_dev *dev; + struct dm_target *ti; + struct list_head entry; sector_t start; /* @@ -181,6 +189,9 @@ struct crypt_config { #define MIN_IOS 16 +static LIST_HEAD(crypt_list); +static DEFINE_MUTEX(crypt_list_mtx); + static void clone_init(struct dm_crypt_io *, struct bio *); static void kcryptd_queue_crypt(struct dm_crypt_io *io); static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq); @@ -1497,12 +1508,33 @@ out: static int crypt_wipe_key(struct crypt_config *cc) { + int ret; + + if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) { + ret = cc->iv_gen_ops->wipe(cc); + if (ret) + return ret; + } + clear_bit(DM_CRYPT_KEY_VALID, &cc->flags); memset(&cc->key, 0, cc->key_size * sizeof(u8)); return crypt_setkey_allcpus(cc); } +static int crypt_suspend_and_wipe_key(struct crypt_config *cc) +{ + int ret; + + if (!dm_suspended(cc->ti)) { + ret = dm_suspend_md(dm_table_get_md(cc->ti->table)); + if (ret) + return ret; + } + + return crypt_wipe_key(cc); +} + static void crypt_dtr(struct dm_target *ti) { struct crypt_config *cc = ti->private; @@ -1512,6 +1544,10 @@ static void crypt_dtr(struct dm_target *ti) if (!cc) return; + mutex_lock(&crypt_list_mtx); + list_del(&cc->entry); + mutex_unlock(&crypt_list_mtx); + if (cc->write_thread) kthread_stop(cc->write_thread); @@ -1738,6 +1774,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) cc->key_size = key_size; ti->private = cc; + cc->ti = ti; ret = crypt_ctr_cipher(ti, argv[0], argv[1]); if (ret < 0) goto bad; @@ -1833,7 +1870,14 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) else if (!strcasecmp(opt_string, "submit_from_crypt_cpus")) set_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags); + else if (!strcasecmp(opt_string, "key_wipe_on_hibernation")) + set_bit(DM_CRYPT_KEY_WIPE_ON_HIBERNATION, &cc->flags); + + else if (!strcasecmp(opt_string, "key_wipe_on_suspend")) + set_bit(DM_CRYPT_KEY_WIPE_ON_SUSPEND, &cc->flags); + else { + ret = -EINVAL; ti->error = "Invalid feature arguments"; goto bad; } @@ -1872,6 +1916,10 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) ti->num_flush_bios = 1; ti->discard_zeroes_data_unsupported = true; + mutex_lock(&crypt_list_mtx); + list_add(&cc->entry, &crypt_list); + mutex_unlock(&crypt_list_mtx); + return 0; bad: @@ -1937,6 +1985,10 @@ static void crypt_status(struct dm_target *ti, status_type_t type, num_feature_args += !!ti->num_discard_bios; num_feature_args += test_bit(DM_CRYPT_SAME_CPU, &cc->flags); num_feature_args += test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags); + num_feature_args += test_bit(DM_CRYPT_KEY_WIPE_ON_HIBERNATION, + &cc->flags); + num_feature_args += test_bit(DM_CRYPT_KEY_WIPE_ON_SUSPEND, + &cc->flags); if (num_feature_args) { DMEMIT(" %d", num_feature_args); if (ti->num_discard_bios) @@ -1945,6 +1997,10 @@ static void crypt_status(struct dm_target *ti, status_type_t type, DMEMIT(" same_cpu_crypt"); if (test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags)) DMEMIT(" submit_from_crypt_cpus"); + if (test_bit(DM_CRYPT_KEY_WIPE_ON_HIBERNATION, &cc->flags)) + DMEMIT(" key_wipe_on_hibernation"); + if (test_bit(DM_CRYPT_KEY_WIPE_ON_SUSPEND, &cc->flags)) + DMEMIT(" key_wipe_on_suspend"); } break; @@ -1980,6 +2036,10 @@ static void crypt_resume(struct dm_target *ti) /* Message interface * key set * key wipe + * key wipe_on_hibernation + * key retain_on_hibernation + * key wipe_on_suspend + * key retain_on_suspend */ static int crypt_message(struct dm_target *ti, unsigned argc, char **argv) { @@ -1990,6 +2050,22 @@ static int crypt_message(struct dm_target *ti, unsigned argc, char **argv) goto error; if (!strcasecmp(argv[0], "key")) { + if (argc == 2 && !strcasecmp(argv[1], "wipe_on_hibernation")) { + set_bit(DM_CRYPT_KEY_WIPE_ON_HIBERNATION, &cc->flags); + return 0; + } + if (argc == 2 && !strcasecmp(argv[1], "retain_on_hibernation")) { + clear_bit(DM_CRYPT_KEY_WIPE_ON_HIBERNATION, &cc->flags); + return 0; + } + if (argc == 2 && !strcasecmp(argv[1], "wipe_on_suspend")) { + set_bit(DM_CRYPT_KEY_WIPE_ON_SUSPEND, &cc->flags); + return 0; + } + if (argc == 2 && !strcasecmp(argv[1], "retain_on_suspend")) { + clear_bit(DM_CRYPT_KEY_WIPE_ON_SUSPEND, &cc->flags); + return 0; + } if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) { DMWARN("not suspended during key manipulation."); return -EINVAL; @@ -2003,11 +2079,6 @@ static int crypt_message(struct dm_target *ti, unsigned argc, char **argv) return ret; } if (argc == 2 && !strcasecmp(argv[1], "wipe")) { - if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) { - ret = cc->iv_gen_ops->wipe(cc); - if (ret) - return ret; - } return crypt_wipe_key(cc); } } @@ -2056,19 +2127,58 @@ static struct target_type crypt_target = { .iterate_devices = crypt_iterate_devices, }; +static int dm_crypt_pm_notifier_call(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct crypt_config *cc; + int r; + + mutex_lock(&crypt_list_mtx); + + list_for_each_entry(cc, &crypt_list, entry) { + if ((action == PM_HIBERNATION_AFTER_FREEZE && + test_bit(DM_CRYPT_KEY_WIPE_ON_HIBERNATION, &cc->flags)) || + (action == PM_SUSPEND_AFTER_FREEZE && + test_bit(DM_CRYPT_KEY_WIPE_ON_SUSPEND, &cc->flags))) { + r = crypt_suspend_and_wipe_key(cc); + if (r) { + DMWARN("wiping key failed %d", r); + } + } + } + + mutex_unlock(&crypt_list_mtx); + + return NOTIFY_OK; +} + +static struct notifier_block dm_crypt_pm_notifier_block = { + .notifier_call = dm_crypt_pm_notifier_call, +}; + static int __init dm_crypt_init(void) { int r; r = dm_register_target(&crypt_target); - if (r < 0) + if (r < 0) { DMERR("register failed %d", r); + return r; + } - return r; + r = register_pm_notifier(&dm_crypt_pm_notifier_block); + if (r) { + DMERR("register_pm_notifier failed %d", r); + dm_unregister_target(&crypt_target); + return r; + } + + return 0; } static void __exit dm_crypt_exit(void) { + unregister_pm_notifier(&dm_crypt_pm_notifier_block); dm_unregister_target(&crypt_target); } -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/