From patchwork Tue Dec 29 08:55:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Satya Tangirala X-Patchwork-Id: 11992081 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-21.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95CBCC433E0 for ; Tue, 29 Dec 2020 08:56:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 60D62207CF for ; Tue, 29 Dec 2020 08:56:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726244AbgL2I4L (ORCPT ); Tue, 29 Dec 2020 03:56:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35332 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725986AbgL2I4K (ORCPT ); Tue, 29 Dec 2020 03:56:10 -0500 Received: from mail-qv1-xf49.google.com (mail-qv1-xf49.google.com [IPv6:2607:f8b0:4864:20::f49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 45912C061799 for ; Tue, 29 Dec 2020 00:55:30 -0800 (PST) Received: by mail-qv1-xf49.google.com with SMTP id t16so11331301qvk.13 for ; Tue, 29 Dec 2020 00:55:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:message-id:mime-version:subject:from:to:cc; bh=RWF45nfESoe/xg6vBm9ZSMGF2K7udGDVIpJcJtV7Ubo=; b=jXKSiCgesR1WHLlKGxh5BW86oNMIY4QYDJZr0J7nxM1A6YFU5oWJeyhimuVROsl9rc D/c7O8dFOGo0kHiN0K3437fWq/Sz/1ADQ3Ay9pGBsVpGEMgKhGDG2tUPuuILqZCcOWdR OultJkN1blTae4NaVaDDhTFF7q327kCHdGY8NkC5/IwnHlTneEAI34zke2/SOLkawf1h Iiq8DJW9Wsye8AzaGkYR7FBWGLfjV+LjtgwyVOORirC2EW0OjOCyzvgcYsEv2LSJ4ov/ LGP8uvlibYMNvRU0Rmh/G+SjIz4Ft34nN737H8w+5Y5Zb+J/dLuW0loMfIH054BU0wjT sd5g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:message-id:mime-version:subject:from :to:cc; bh=RWF45nfESoe/xg6vBm9ZSMGF2K7udGDVIpJcJtV7Ubo=; b=GhosgJ8SLZ1Fvjuaj9q1AUDmlXavR060/ZhSvzKGTmUqpk0PyJtgXLWuKxmyRrzYjG nOCYylubyU3Frmsb6qEZBaRf/zdpcESjoldRJH5csnnbN/kMqC2bUHTwQBCAxnu2JV1x NWD09kZ9kuBOpu8HQTdQ8JVoetBmFZut25WjS+EyX6W4XN5tj7jLWgi7D5Vu9Ebo2FTC 5OyNgi0iPrNDzn0JV5wtDKe0NdrR9NsT2eJk0gEE0LE+Xm/VHiEG10s+BKoPCnePFUfl 3cp+4pxlcTnZjPSMiv/GKn877m0+8+nZPN4QMAPozoN4Yt+xalA93saluihmd38lVsBb qACA== X-Gm-Message-State: AOAM531UUiW6MBhuqaC2JdObd90+ZTX6wYwPc2ug/Taeb7Dyl7hN2Q4Y WGiUmuNm5Drr5mirVBGs0uwXs4OxF+Kcbs/03dlMh16yP0+1crrdfsUqHO7gQCTGxWfJsUj2BO1 zpoK1R6y/wOi0e8/3Ciajs2dZsIyV62GphFbhlm7AxtLBKMb82+vnG8OjG2KPo/aneQrz X-Google-Smtp-Source: ABdhPJyvfLRGDggGOMtCa+n52qb+E+PZ9C1ZijQyrf0ise7owIlupD7UN+RW9xEOLCNp/pRUGtp9/HE1oZs= Sender: "satyat via sendgmr" X-Received: from satyaprateek.c.googlers.com ([fda3:e722:ac3:10:24:72f4:c0a8:1092]) (user=satyat job=sendgmr) by 2002:a05:6214:1266:: with SMTP id r6mr50672101qvv.12.1609232129361; Tue, 29 Dec 2020 00:55:29 -0800 (PST) Date: Tue, 29 Dec 2020 08:55:18 +0000 Message-Id: <20201229085524.2795331-1-satyat@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.29.2.729.g45daf8777d-goog Subject: [PATCH v3 0/6] add support for inline encryption to device mapper From: Satya Tangirala To: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com Cc: Jens Axboe , Alasdair Kergon , Mike Snitzer , Eric Biggers , Satya Tangirala Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This patch series adds support for inline encryption to the device mapper. Patch 1 introduces the "passthrough" keyslot manager. The regular keyslot manager is designed for inline encryption hardware that have only a small fixed number of keyslots. A DM device itself does not actually have only a small fixed number of keyslots - it doesn't actually have any keyslots in the first place, and programming an encryption context into a DM device doesn't make much semantic sense. It is possible for a DM device to set up a keyslot manager with some "sufficiently large" number of keyslots in its request queue, so that upper layers can use the inline encryption capabilities of the DM device's underlying devices, but the memory being allocated for the DM device's keyslots is a waste since they won't actually be used by the DM device. The passthrough keyslot manager solves this issue - when the block layer sees that a request queue has a passthrough keyslot manager, it doesn't attempt to program any encryption context into the keyslot manager. The passthrough keyslot manager only allows the device to expose its inline encryption capabilities, and a way for upper layers to evict keys if necessary. There also exist inline encryption hardware that can handle encryption contexts directly, and allow users to pass them a data request along with the encryption context (as opposed to inline encryption hardware that require users to first program a keyslot with an encryption context, and then require the users to pass the keyslot index with the data request). Such devices can also make use of the passthrough keyslot manager. Patch 2 introduces some keyslot manager functions useful for the device mapper. Patch 3 introduces the changes for inline encryption support for the device mapper. A DM device only exposes the intersection of the crypto capabilities of its underlying devices. This is so that in case a bio with an encryption context is eventually mapped to an underlying device that doesn't support that encryption context, the blk-crypto-fallback's cipher tfms are allocated ahead of time by the call to blk_crypto_start_using_key. Each DM target can now also specify the "DM_TARGET_PASSES_CRYPTO" flag in the target type features to opt-in to supporting passing through the underlying inline encryption capabilities. This flag is needed because it doesn't make much semantic sense for certain targets like dm-crypt to expose the underlying inline encryption capabilities to the upper layers. Again, the DM exposes inline encryption capabilities of the underlying devices only if all of them opt-in to passing through inline encryption support. A DM device's keyslot manager is set up whenever a new table is swapped in. This patch only allows the keyslot manager's capabilities to *expand* because of table changes. In this patch, the new inline encryption capabilities are only verified and used when the table is *swapped* - nothing is done when a new table is loaded (Patch 5 changes this behaviour). This patch also only exposes the intersection of the underlying device's capabilities, which has the effect of causing en/decryption of a bio to fall back to the kernel crypto API (if the fallback is enabled) whenever any of the underlying devices doesn't support the encryption context of the bio - it might be possible to make the bio only fall back to the kernel crypto API if the bio's target underlying device doesn't support the bio's encryption context, but the use case may be uncommon enough in the first place not to warrant worrying about it right now. Patch 4 makes DM evict a key from all its underlying devices when asked to evict a key. Patch 5 verifies the inline encryption capabilities of a new table when it's loaded. Any attempts to load a new table that would cause crypto capabilities to be dropped are rejected at load time, with this patch. Still, the keyslot manager for the DM device is only modified when the table is actually swapped in, since the capabilities of the device may change further due to changes in capabilities of underlying devices between the time the table load and table swap happen. Patch 6 makes some DM targets opt-in to passing through inline encryption support. It does not (yet) try to enable this option with dm-raid, since users can "hot add" disks to a raid device, which makes this not completely straightforward (we'll need to ensure that any "hot added" disks must have a superset of the inline encryption capabilities of the rest of the disks in the raid device, due to the way Patch 2 of this series works). Changes v2 => v3: - Split up the main DM patch into 4 separate patches - Removed the priv variable added to struct keyslot manager in v2 - Use a flag in target type features for opting-in to inline encryption support, instead of using "may_passthrough_inline_crypto" - cleanups and restructure code Changes v1 => v2: - Introduce private field to struct blk_keyslot_manager - Allow the DM keyslot manager to expand its crypto capabilities if the table is changed. - Make DM reject table changes that would otherwise cause crypto capabilities to be dropped. - Allocate the DM device's keyslot manager only when at least one crypto capability is supported (since a NULL value for q->ksm represents "no crypto support" anyway). - Remove the struct blk_keyslot_manager field from struct mapped_device. This patch now relies on just directly setting up the keyslot manager in the request queue, since each DM device is tied to only 1 queue. Satya Tangirala (6): block: keyslot-manager: Introduce passthrough keyslot manager block: keyslot-manager: Introduce functions for device mapper support dm: add support for passing through inline crypto support dm: Support key eviction from keyslot managers of underlying devices dm: Verify inline encryption capabilities of new table when it is loaded dm: set DM_TARGET_PASSES_CRYPTO feature for some targets block/blk-crypto.c | 1 + block/keyslot-manager.c | 130 +++++++++++++++++ drivers/md/dm-flakey.c | 4 +- drivers/md/dm-ioctl.c | 8 ++ drivers/md/dm-linear.c | 5 +- drivers/md/dm.c | 242 +++++++++++++++++++++++++++++++- drivers/md/dm.h | 19 +++ include/linux/device-mapper.h | 6 + include/linux/keyslot-manager.h | 19 +++ 9 files changed, 430 insertions(+), 4 deletions(-)