From patchwork Tue Dec 29 08:55:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Satya Tangirala X-Patchwork-Id: 11992083 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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,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 EE3E6C433DB for ; Tue, 29 Dec 2020 08:57:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B13BD208BA for ; Tue, 29 Dec 2020 08:57:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726352AbgL2I4m (ORCPT ); Tue, 29 Dec 2020 03:56:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35420 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726325AbgL2I4m (ORCPT ); Tue, 29 Dec 2020 03:56:42 -0500 Received: from mail-pf1-x44a.google.com (mail-pf1-x44a.google.com [IPv6:2607:f8b0:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A63BAC06179E for ; Tue, 29 Dec 2020 00:55:33 -0800 (PST) Received: by mail-pf1-x44a.google.com with SMTP id w135so4274327pff.1 for ; Tue, 29 Dec 2020 00:55:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=oQsgXW2m3Lmb+1g8leuyI0Rqgmihl04oDOtjZgFILuI=; b=pjc3NAqBW7CmECssQn/JQztInm5nvNE43XL87fIYpXbl30zM40Lus9TTqhsw5FlwHO mHHBl5JdJ8L9pmlfDwuSFEIEKJ3y5G1QaEf0WT9UR3vUiPBhENjNU7Mcghe9FDW2pEqS fSJhZqNAeInqqzmMI+qngOOxE9cojB9HFhuXgFdVcYPPQ3Z4Pwr1o8py8Vfb17agRoDk K5rpH6h5LAWHBZIpnWYcby2sLy4rrkO4hyle3Zj2PMSCTsUzutWdUihadjmKFYuhwJq6 uq5AWsZE5f3jhyFFYpxGso+EPIkiDnjTgL6MepxugzXt/K8Po0bLi1z9v+YPdKOEGBbo UefQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=oQsgXW2m3Lmb+1g8leuyI0Rqgmihl04oDOtjZgFILuI=; b=pm7VpQgKAh2mMk6ayR8RLSlLan/d+e2x0bkjkscXbWgxGLH1z7CAZH49dhFcIKS95h I4Wlg12RfbG3IQNghjzRSLtEAS/ktDKaolkfaL/TMnV0dkM9F0/Kb1hUi6xsCpssqAJ8 esKrbld1wh1xvSK6bUbF9UeDUQb6aD9xPt6L7Q/8VoH9pU0+VWernI3NWF73kRvdCzoI 10ES5yX10VelFjzjKcblUGFv2q+Tjc8TkZAe9dXf+Fnq4EfT0+XkOajHaI0b435N2NEa H9bG/0L4D6z71+6F2adi6+o5OQLDfguNh+oan0VLXWRTCXvHFpQFq+JTE4gZTeQmcQTi EcOw== X-Gm-Message-State: AOAM530lrdLKdy2QZKXO/gbC4hf4wWV+wUqpFO9FnPsyVRGUNIGpZvOE APRCNzXgViXMBg7AbLWdNcZN+0+jr9ytBr84HKWS0m8mqLj8I994LYlMBrGTQ4ArEDWHY5j1IHU t7PLRYv9kNBtmiLpgZoxkGpSsl2U7RVVarWeVpnXSV8C0do50qhxYrybopiZFuKqyfkp/ X-Google-Smtp-Source: ABdhPJzmLLIYwSw6PZyRw+ISTt9Qf+Y58eAw1eYKXw/8D8joWkNR7O6foCuOQAFTP3qWqk2KVWjbSGcUX0A= 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:a17:902:5997:b029:da:a1cd:3cc2 with SMTP id p23-20020a1709025997b02900daa1cd3cc2mr25543598pli.80.1609232133020; Tue, 29 Dec 2020 00:55:33 -0800 (PST) Date: Tue, 29 Dec 2020 08:55:20 +0000 In-Reply-To: <20201229085524.2795331-1-satyat@google.com> Message-Id: <20201229085524.2795331-3-satyat@google.com> Mime-Version: 1.0 References: <20201229085524.2795331-1-satyat@google.com> X-Mailer: git-send-email 2.29.2.729.g45daf8777d-goog Subject: [PATCH v3 2/6] block: keyslot-manager: Introduce functions for device mapper support 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 Introduce blk_ksm_update_capabilities() to update the capabilities of a keyslot manager (ksm) in-place. The pointer to a ksm in a device's request queue may not be easily replaced, because upper layers like the filesystem might access it (e.g. for programming keys/checking capabilities) at the same time the device wants to replace that request queue's ksm (and free the old ksm's memory). This function allows the device to update the capabilities of the ksm in its request queue directly. Also introduce blk_ksm_is_superset() which checks whether one ksm's capabilities are a (not necessarily strict) superset of another ksm's. The blk-crypto framework requires that crypto capabilities that were advertised when a bio was created continue to be supported by the device until that bio is ended - in practice this probably means that a device's advertised crypto capabilities can *never* "shrink" (since there's no synchronization between bio creation and when a device may want to change its advertised capabilities) - so a previously advertised crypto capability must always continue to be supported. This function can be used to check that a new ksm is a valid replacement for an old ksm. Signed-off-by: Satya Tangirala --- block/keyslot-manager.c | 91 +++++++++++++++++++++++++++++++++ include/linux/keyslot-manager.h | 9 ++++ 2 files changed, 100 insertions(+) diff --git a/block/keyslot-manager.c b/block/keyslot-manager.c index ac7ce83a76e8..f13ab7410eca 100644 --- a/block/keyslot-manager.c +++ b/block/keyslot-manager.c @@ -424,6 +424,97 @@ void blk_ksm_unregister(struct request_queue *q) q->ksm = NULL; } +/** + * blk_ksm_intersect_modes() - restrict supported modes by child device + * @parent: The keyslot manager for parent device + * @child: The keyslot manager for child device, or NULL + * + * Clear any crypto mode support bits in @parent that aren't set in @child. + * If @child is NULL, then all parent bits are cleared. + * + * Only use this when setting up the keyslot manager for a layered device, + * before it's been exposed yet. + */ +void blk_ksm_intersect_modes(struct blk_keyslot_manager *parent, + const struct blk_keyslot_manager *child) +{ + if (child) { + unsigned int i; + + parent->max_dun_bytes_supported = + min(parent->max_dun_bytes_supported, + child->max_dun_bytes_supported); + for (i = 0; i < ARRAY_SIZE(child->crypto_modes_supported); + i++) { + parent->crypto_modes_supported[i] &= + child->crypto_modes_supported[i]; + } + } else { + parent->max_dun_bytes_supported = 0; + memset(parent->crypto_modes_supported, 0, + sizeof(parent->crypto_modes_supported)); + } +} +EXPORT_SYMBOL_GPL(blk_ksm_intersect_modes); + +/** + * blk_ksm_is_superset() - Check if a KSM supports a superset of crypto modes + * and DUN bytes that another KSM supports. Here, + * "superset" refers to the mathematical meaning of the + * word - i.e. if two KSMs have the *same* capabilities, + * they *are* considered supersets of each other. + * @ksm_superset: The KSM that we want to verify is a superset + * @ksm_subset: The KSM that we want to verify is a subset + * + * Return: True if @ksm_superset supports a superset of the crypto modes and DUN + * bytes that @ksm_subset supports. + */ +bool blk_ksm_is_superset(struct blk_keyslot_manager *ksm_superset, + struct blk_keyslot_manager *ksm_subset) +{ + int i; + + if (!ksm_subset) + return true; + + if (!ksm_superset) + return false; + + for (i = 0; i < ARRAY_SIZE(ksm_superset->crypto_modes_supported); i++) { + if (ksm_subset->crypto_modes_supported[i] & + (~ksm_superset->crypto_modes_supported[i])) { + return false; + } + } + + if (ksm_subset->max_dun_bytes_supported > + ksm_superset->max_dun_bytes_supported) { + return false; + } + + return true; +} +EXPORT_SYMBOL_GPL(blk_ksm_is_superset); + +/** + * blk_ksm_update_capabilities() - Update the restrictions of a KSM to those of + * another KSM + * @target_ksm: The KSM whose restrictions to update. + * @reference_ksm: The KSM to whose restrictions this function will update + * @target_ksm's restrictions to, + */ +void blk_ksm_update_capabilities(struct blk_keyslot_manager *target_ksm, + struct blk_keyslot_manager *reference_ksm) +{ + memcpy(target_ksm->crypto_modes_supported, + reference_ksm->crypto_modes_supported, + sizeof(target_ksm->crypto_modes_supported)); + + target_ksm->max_dun_bytes_supported = + reference_ksm->max_dun_bytes_supported; +} +EXPORT_SYMBOL_GPL(blk_ksm_update_capabilities); + /** * blk_ksm_init_passthrough() - Init a passthrough keyslot manager * @ksm: The keyslot manager to init diff --git a/include/linux/keyslot-manager.h b/include/linux/keyslot-manager.h index 323e15dd6fa7..164568f52be7 100644 --- a/include/linux/keyslot-manager.h +++ b/include/linux/keyslot-manager.h @@ -103,6 +103,15 @@ void blk_ksm_reprogram_all_keys(struct blk_keyslot_manager *ksm); void blk_ksm_destroy(struct blk_keyslot_manager *ksm); +void blk_ksm_intersect_modes(struct blk_keyslot_manager *parent, + const struct blk_keyslot_manager *child); + void blk_ksm_init_passthrough(struct blk_keyslot_manager *ksm); +bool blk_ksm_is_superset(struct blk_keyslot_manager *ksm_superset, + struct blk_keyslot_manager *ksm_subset); + +void blk_ksm_update_capabilities(struct blk_keyslot_manager *target_ksm, + struct blk_keyslot_manager *reference_ksm); + #endif /* __LINUX_KEYSLOT_MANAGER_H */