From patchwork Sun May 3 18:43:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Maxim Levitsky X-Patchwork-Id: 11524697 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2C19315AB for ; Sun, 3 May 2020 18:45:23 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 E5C8A206E9 for ; Sun, 3 May 2020 18:45:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="PYNcMhhA" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E5C8A206E9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:33556 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jVJc9-0006bh-SZ for patchwork-qemu-devel@patchwork.kernel.org; Sun, 03 May 2020 14:45:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59708) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jVJal-0003Qq-Hw for qemu-devel@nongnu.org; Sun, 03 May 2020 14:43:56 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:25257 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jVJai-0000Hw-3o for qemu-devel@nongnu.org; Sun, 03 May 2020 14:43:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588531431; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=OuJCC4yvdsgHcVmJt9UEyNPfUmULcihtHXyw9JOIlZY=; b=PYNcMhhA7b7Dg4CB+lcSh61bR1K9hJrfOHxt7eD23rNCCE479iMIlyF78A31ORVmjiprvz m9WPDm4HuYVK0iqkyWFUfecj4itx7bzxJ1sQZ/nTP5hUYLdtNBf0A8xNs1MgHEEDKcvYn4 GFRQRXcacop1gKZIkVS90ZqjvvQz9DQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-287-yfbiTyWOO8KVTKy5OOATzQ-1; Sun, 03 May 2020 14:43:49 -0400 X-MC-Unique: yfbiTyWOO8KVTKy5OOATzQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BE0A745F; Sun, 3 May 2020 18:43:48 +0000 (UTC) Received: from maximlenovopc.usersys.redhat.com (unknown [10.35.206.195]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7B02A5C1B2; Sun, 3 May 2020 18:43:46 +0000 (UTC) From: Maxim Levitsky To: qemu-devel@nongnu.org Subject: [PATCH v3 07/14] block/crypto: implement the encryption key management Date: Sun, 3 May 2020 21:43:17 +0300 Message-Id: <20200503184324.12506-8-mlevitsk@redhat.com> In-Reply-To: <20200503184324.12506-1-mlevitsk@redhat.com> References: <20200503184324.12506-1-mlevitsk@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.120; envelope-from=mlevitsk@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/03 14:43:32 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , qemu-block@nongnu.org, Markus Armbruster , Max Reitz , Maxim Levitsky , John Snow Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" This implements the encryption key management using the generic code in qcrypto layer and exposes it to the user via qemu-img This code adds another 'write_func' because the initialization write_func works directly on the underlying file, and amend works on instance of luks device. This commit also adds a 'hack/workaround' I and Kevin Wolf (thanks) made to make the driver both support write sharing (to avoid breaking the users), and be safe against concurrent metadata update (the keyslots) Eventually the write sharing for luks driver will be deprecated and removed together with this hack. The hack is that we ask (as a format driver) for BLK_PERM_CONSISTENT_READ and then when we want to update the keys, we unshare that permission. So if someone else has the image open, even readonly, encryption key update will fail gracefully. Also thanks to Daniel Berrange for the idea of unsharing read, rather that write permission which allows to avoid cases when the other user had opened the image read-only. Signed-off-by: Maxim Levitsky Reviewed-by: Daniel P. Berrangé --- block/crypto.c | 127 +++++++++++++++++++++++++++++++++++++++++++++++-- block/crypto.h | 34 +++++++++++++ 2 files changed, 158 insertions(+), 3 deletions(-) diff --git a/block/crypto.c b/block/crypto.c index 13ca1ad891..b71e57f777 100644 --- a/block/crypto.c +++ b/block/crypto.c @@ -37,6 +37,7 @@ typedef struct BlockCrypto BlockCrypto; struct BlockCrypto { QCryptoBlock *block; + bool updating_keys; }; @@ -71,6 +72,24 @@ static ssize_t block_crypto_read_func(QCryptoBlock *block, return ret; } +static ssize_t block_crypto_write_func(QCryptoBlock *block, + size_t offset, + const uint8_t *buf, + size_t buflen, + void *opaque, + Error **errp) +{ + BlockDriverState *bs = opaque; + ssize_t ret; + + ret = bdrv_pwrite(bs->file, offset, buf, buflen); + if (ret < 0) { + error_setg_errno(errp, -ret, "Could not write encryption header"); + return ret; + } + return ret; +} + struct BlockCryptoCreateData { BlockBackend *blk; @@ -149,6 +168,19 @@ static QemuOptsList block_crypto_create_opts_luks = { }; +static QemuOptsList block_crypto_amend_opts_luks = { + .name = "crypto", + .head = QTAILQ_HEAD_INITIALIZER(block_crypto_create_opts_luks.head), + .desc = { + BLOCK_CRYPTO_OPT_DEF_LUKS_STATE(""), + BLOCK_CRYPTO_OPT_DEF_LUKS_KEYSLOT(""), + BLOCK_CRYPTO_OPT_DEF_LUKS_OLD_SECRET(""), + BLOCK_CRYPTO_OPT_DEF_LUKS_NEW_SECRET(""), + BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME(""), + { /* end of list */ } + }, +}; + QCryptoBlockOpenOptions * block_crypto_open_opts_init(QDict *opts, Error **errp) { @@ -742,6 +774,95 @@ block_crypto_get_specific_info_luks(BlockDriverState *bs, Error **errp) return spec_info; } +static int +block_crypto_amend_options_luks(BlockDriverState *bs, + QemuOpts *opts, + BlockDriverAmendStatusCB *status_cb, + void *cb_opaque, + bool force, + Error **errp) +{ + BlockCrypto *crypto = bs->opaque; + QDict *cryptoopts = NULL; + QCryptoBlockAmendOptions *amend_options = NULL; + int ret; + + assert(crypto); + assert(crypto->block); + crypto->updating_keys = true; + + ret = bdrv_child_refresh_perms(bs, bs->file, errp); + if (ret < 0) { + goto cleanup; + } + + cryptoopts = qemu_opts_to_qdict(opts, NULL); + qdict_put_str(cryptoopts, "format", "luks"); + amend_options = block_crypto_amend_opts_init(cryptoopts, errp); + if (!amend_options) { + ret = -EINVAL; + goto cleanup; + } + + ret = qcrypto_block_amend_options(crypto->block, + block_crypto_read_func, + block_crypto_write_func, + bs, + amend_options, + force, + errp); +cleanup: + crypto->updating_keys = false; + bdrv_child_refresh_perms(bs, bs->file, errp); + qapi_free_QCryptoBlockAmendOptions(amend_options); + qobject_unref(cryptoopts); + return ret; +} + + +static void +block_crypto_child_perms(BlockDriverState *bs, BdrvChild *c, + const BdrvChildRole *role, + BlockReopenQueue *reopen_queue, + uint64_t perm, uint64_t shared, + uint64_t *nperm, uint64_t *nshared) +{ + + BlockCrypto *crypto = bs->opaque; + + bdrv_filter_default_perms(bs, c, role, reopen_queue, + perm, shared, nperm, nshared); + /* + * Ask for consistent read permission so that if + * someone else tries to open this image with this permission + * neither will be able to edit encryption keys, since + * we will unshare that permission while trying to + * update the encryption keys + */ + if (!(bs->open_flags & BDRV_O_NO_IO)) { + *nperm |= BLK_PERM_CONSISTENT_READ; + } + /* + * This driver doesn't modify LUKS metadata except + * when updating the encryption slots. + * Thus unlike a proper format driver we don't ask for + * shared write/read permission. However we need it + * when we are updating the keys, to ensure that only we + * have access to the device. + * + * Encryption update will set the crypto->updating_keys + * during that period and refresh permissions + * + */ + if (crypto->updating_keys) { + /* need exclusive write access for header update */ + *nperm |= BLK_PERM_WRITE; + /* unshare read and write permission */ + *nshared &= ~(BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE); + } +} + + static const char *const block_crypto_strong_runtime_opts[] = { BLOCK_CRYPTO_OPT_LUKS_KEY_SECRET, @@ -754,13 +875,12 @@ static BlockDriver bdrv_crypto_luks = { .bdrv_probe = block_crypto_probe_luks, .bdrv_open = block_crypto_open_luks, .bdrv_close = block_crypto_close, - /* This driver doesn't modify LUKS metadata except when creating image. - * Allow share-rw=on as a special case. */ - .bdrv_child_perm = bdrv_filter_default_perms, + .bdrv_child_perm = block_crypto_child_perms, .bdrv_co_create = block_crypto_co_create_luks, .bdrv_co_create_opts = block_crypto_co_create_opts_luks, .bdrv_co_truncate = block_crypto_co_truncate, .create_opts = &block_crypto_create_opts_luks, + .amend_opts = &block_crypto_amend_opts_luks, .bdrv_reopen_prepare = block_crypto_reopen_prepare, .bdrv_refresh_limits = block_crypto_refresh_limits, @@ -770,6 +890,7 @@ static BlockDriver bdrv_crypto_luks = { .bdrv_measure = block_crypto_measure, .bdrv_get_info = block_crypto_get_info_luks, .bdrv_get_specific_info = block_crypto_get_specific_info_luks, + .bdrv_amend_options = block_crypto_amend_options_luks, .strong_runtime_opts = block_crypto_strong_runtime_opts, }; diff --git a/block/crypto.h b/block/crypto.h index 06e044c9be..c72c3dec61 100644 --- a/block/crypto.h +++ b/block/crypto.h @@ -41,6 +41,11 @@ #define BLOCK_CRYPTO_OPT_LUKS_IVGEN_HASH_ALG "ivgen-hash-alg" #define BLOCK_CRYPTO_OPT_LUKS_HASH_ALG "hash-alg" #define BLOCK_CRYPTO_OPT_LUKS_ITER_TIME "iter-time" +#define BLOCK_CRYPTO_OPT_LUKS_KEYSLOT "keyslot" +#define BLOCK_CRYPTO_OPT_LUKS_STATE "state" +#define BLOCK_CRYPTO_OPT_LUKS_OLD_SECRET "old-secret" +#define BLOCK_CRYPTO_OPT_LUKS_NEW_SECRET "new-secret" + #define BLOCK_CRYPTO_OPT_DEF_LUKS_KEY_SECRET(prefix) \ BLOCK_CRYPTO_OPT_DEF_KEY_SECRET(prefix, \ @@ -88,6 +93,35 @@ .help = "Time to spend in PBKDF in milliseconds", \ } +#define BLOCK_CRYPTO_OPT_DEF_LUKS_STATE(prefix) \ + { \ + .name = prefix BLOCK_CRYPTO_OPT_LUKS_STATE, \ + .type = QEMU_OPT_STRING, \ + .help = "Select new state of affected keyslots (active/inactive)",\ + } + +#define BLOCK_CRYPTO_OPT_DEF_LUKS_KEYSLOT(prefix) \ + { \ + .name = prefix BLOCK_CRYPTO_OPT_LUKS_KEYSLOT, \ + .type = QEMU_OPT_NUMBER, \ + .help = "Select a single keyslot to modify explicitly",\ + } + +#define BLOCK_CRYPTO_OPT_DEF_LUKS_OLD_SECRET(prefix) \ + { \ + .name = prefix BLOCK_CRYPTO_OPT_LUKS_OLD_SECRET, \ + .type = QEMU_OPT_STRING, \ + .help = "Select all keyslots that match this password", \ + } + +#define BLOCK_CRYPTO_OPT_DEF_LUKS_NEW_SECRET(prefix) \ + { \ + .name = prefix BLOCK_CRYPTO_OPT_LUKS_NEW_SECRET, \ + .type = QEMU_OPT_STRING, \ + .help = "New secret to set in the matching keyslots. " \ + "Empty string to erase", \ + } + QCryptoBlockCreateOptions * block_crypto_create_opts_init(QDict *opts, Error **errp);