From patchwork Thu Jun 25 12:55:42 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 11625223 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 A815514B7 for ; Thu, 25 Jun 2020 13:04:27 +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 6E2F020672 for ; Thu, 25 Jun 2020 13:04:27 +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="cW/zr/HI" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6E2F020672 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]:43630 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1joRYI-00088L-MT for patchwork-qemu-devel@patchwork.kernel.org; Thu, 25 Jun 2020 09:04:26 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49934) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1joRQn-0003vM-Hb for qemu-devel@nongnu.org; Thu, 25 Jun 2020 08:56:41 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:53500 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 1joRQk-0003M9-4H for qemu-devel@nongnu.org; Thu, 25 Jun 2020 08:56:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593089796; 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=7REDxmh3fNeouy7lNhFw+K1ulOsaVH94F15egehUhgc=; b=cW/zr/HIc6TfNdoqVbqMK9QmzyAseQrCWWvCI/IhiCnz6r/+zXxRO2LhF60DbJI0HCg8Cb g3oPHOms8Oqh2eW/Oe+27ZpmwuJAEd+uQHiNGRvJ9av0VehNcLOnrJiW076pbJvr6A+xnM LMuuNSBK29rRDd/aNmobKv168TrvUoY= 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-41-ZMiljqtyPyC4f8FGzQLAlQ-1; Thu, 25 Jun 2020 08:56:31 -0400 X-MC-Unique: ZMiljqtyPyC4f8FGzQLAlQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B180018B638D; Thu, 25 Jun 2020 12:56:30 +0000 (UTC) Received: from localhost (ovpn-113-182.ams2.redhat.com [10.36.113.182]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AC6D89CA0; Thu, 25 Jun 2020 12:56:25 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Subject: [PATCH 13/19] block/crypto: implement the encryption key management Date: Thu, 25 Jun 2020 14:55:42 +0200 Message-Id: <20200625125548.870061-14-mreitz@redhat.com> In-Reply-To: <20200625125548.870061-1-mreitz@redhat.com> References: <20200625125548.870061-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.120; envelope-from=mreitz@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/25 01:47:53 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, 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 , Maxim Levitsky , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" From: Maxim Levitsky 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 Reviewed-by: Max Reitz Message-Id: <20200608094030.670121-8-mlevitsk@redhat.com> Signed-off-by: Max Reitz --- block/crypto.h | 34 +++++++++++++ block/crypto.c | 130 +++++++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 161 insertions(+), 3 deletions(-) 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); diff --git a/block/crypto.c b/block/crypto.c index 1960b47ceb..b9c40e6922 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; @@ -166,6 +185,19 @@ 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) { @@ -758,6 +790,98 @@ 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_default_perms(bs, c, role, reopen_queue, perm, shared, nperm, nshared); + + /* + * For backward compatibility, manually share the write + * and resize permission + */ + *nshared |= (BLK_PERM_WRITE | BLK_PERM_RESIZE); + /* + * Since we are not fully a format driver, don't always request + * the read/resize permission but only when explicitly + * requested + */ + *nperm &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE); + *nperm |= perm & (BLK_PERM_WRITE | BLK_PERM_RESIZE); + + /* + * 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, @@ -770,13 +894,12 @@ 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_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, @@ -786,6 +909,7 @@ 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, .is_format = true,