From patchwork Thu Jan 6 20:34:34 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thore Sommer X-Patchwork-Id: 12705696 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 80DF9C433F5 for ; Thu, 6 Jan 2022 20:34:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243881AbiAFUex (ORCPT ); Thu, 6 Jan 2022 15:34:53 -0500 Received: from mo4-p01-ob.smtp.rzone.de ([85.215.255.50]:45015 "EHLO mo4-p01-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243914AbiAFUex (ORCPT ); Thu, 6 Jan 2022 15:34:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1641501292; s=strato-dkim-0002; d=thson.de; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Cc:Date: From:Subject:Sender; bh=Gw9uGHd8kShMn9q0DWe+3Hm/MOu0N2IHugHMPsF3NHU=; b=GBGeEOjDcOl8Jr5zw7j/85r2/KKQXcDq1ukvJpuhw2FqbejInumyv0haZhnwu/WIqJ Hv1/isyU3QUf1u2pJDiONsO4VuYmoLitqSOCAEyPp1NnANB9M1RU3CgaG86ccOii8yyI 2KVFm0IkuwfakAN6MEs9+40jtbPSICuwwWu8HXKhT5SlXBRMmLTGXqeyh+TdqFvLVxHS FaK9xMrd/lozz3wD1gQZwdHI9R/XEyudfBNdczvZUoyRnCJ+tB2X+5OcrCaX8Ws/V8DA zlyhlQTCsoXet0tPearKoMdY/1GsjUlrxR+Q0i72Zpb1+2Dj548/hfDw9mbx6afDCw/Y qkKg== Authentication-Results: strato.com; dkim=none X-RZG-AUTH: ":PHkGeUmrW+uCZmxs998QJRUX30nOwJd7nOD9sw/xoauycprg5uef7cgCEpy7sPc=" X-RZG-CLASS-ID: mo00 Received: from USER-PC.fritz.box by smtp.strato.de (RZmta 47.37.6 DYNA|AUTH) with ESMTPSA id k3f463y06KYp05f (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Thu, 6 Jan 2022 21:34:51 +0100 (CET) From: Thore Sommer To: dm-devel@redhat.com, agk@redhat.com, snitzer@redhat.com Cc: tusharsu@linux.microsoft.com, linux-integrity@vger.kernel.org, Thore Sommer Subject: [RFC PATCH 1/3] dm ima: allow targets to remeasure their table entry Date: Thu, 6 Jan 2022 21:34:34 +0100 Message-Id: <20220106203436.281629-2-public@thson.de> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220106203436.281629-1-public@thson.de> References: <20220106203436.281629-1-public@thson.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org A new DM event dm_target_update is introduced for targets to remeasure their table entry. This is intended for targets that indicate security relevant events by updating one of their table entries (e.g. verity for corruption). In the event the dm version, device metadata and target data gets measured. This does not update the hash of the active table because it would require to rehash the whole table with all the other targets entries. Signed-off-by: Thore Sommer --- drivers/md/dm-ima.c | 76 +++++++++++++++++++++++++++++++++++++++++++++ drivers/md/dm-ima.h | 2 ++ 2 files changed, 78 insertions(+) diff --git a/drivers/md/dm-ima.c b/drivers/md/dm-ima.c index 957999998d70..3b1bb97263d9 100644 --- a/drivers/md/dm-ima.c +++ b/drivers/md/dm-ima.c @@ -750,3 +750,79 @@ void dm_ima_measure_on_device_rename(struct mapped_device *md) kfree(new_dev_name); kfree(new_dev_uuid); } + +/* + * Give the option for targets to remeasure on state change. + */ +void dm_ima_measure_on_target_update(struct dm_target *ti) +{ + char *ima_buf = NULL, *target_metadata_buf = NULL, *target_data_buf = NULL; + struct dm_target *ti2; + size_t target_metadata_buf_len, target_data_buf_len; + unsigned int num_targets, target_index; + struct dm_table *table = ti->table; + struct mapped_device *md = table->md; + bool found = false; + bool noio = true; + int l = 0; + + ima_buf = dm_ima_alloc(DM_IMA_MEASUREMENT_BUF_LEN, GFP_KERNEL, noio); + if (!ima_buf) + return; + + target_metadata_buf = dm_ima_alloc(DM_IMA_TARGET_METADATA_BUF_LEN, GFP_KERNEL, noio); + if (!target_metadata_buf) + goto exit; + + target_data_buf = dm_ima_alloc(DM_IMA_TARGET_DATA_BUF_LEN, GFP_KERNEL, noio); + if (!target_data_buf) + goto exit; + + /* + * Get the index of the target in the table. + */ + num_targets = dm_table_get_num_targets(table); + for (target_index = 0; target_index < num_targets; target_index++) { + ti2 = dm_table_get_target(table, target_index); + if (!ti) + goto exit; + if (ti == ti2) { + found = true; + break; + } + } + if (!found) + goto exit; + + scnprintf(target_metadata_buf, DM_IMA_TARGET_METADATA_BUF_LEN, + "target_index=%d,target_begin=%llu,target_len=%llu,", + target_index, ti->begin, ti->len); + target_metadata_buf_len = strlen(target_metadata_buf); + + if (ti->type->status) + ti->type->status(ti, STATUSTYPE_IMA, STATUSTYPE_IMA, target_data_buf, + DM_IMA_TARGET_DATA_BUF_LEN); + else + target_data_buf[0] = '\0'; + target_data_buf_len = strlen(target_data_buf); + + memcpy(ima_buf + l, DM_IMA_VERSION_STR, md->ima.dm_version_str_len); + l += md->ima.dm_version_str_len; + + memcpy(ima_buf + l, md->ima.active_table.device_metadata, + md->ima.active_table.device_metadata_len); + l += md->ima.active_table.device_metadata_len; + + memcpy(ima_buf + l, target_metadata_buf, target_metadata_buf_len); + l += target_metadata_buf_len; + + memcpy(ima_buf + l, target_data_buf, target_data_buf_len); + + dm_ima_measure_data("dm_target_update", ima_buf, strlen(ima_buf), noio); + +exit: + kfree(ima_buf); + kfree(target_data_buf); + kfree(target_metadata_buf); +} +EXPORT_SYMBOL_GPL(dm_ima_measure_on_target_update); diff --git a/drivers/md/dm-ima.h b/drivers/md/dm-ima.h index b8c3b614670b..281a8b65f8a9 100644 --- a/drivers/md/dm-ima.h +++ b/drivers/md/dm-ima.h @@ -63,6 +63,7 @@ void dm_ima_measure_on_device_resume(struct mapped_device *md, bool swap); void dm_ima_measure_on_device_remove(struct mapped_device *md, bool remove_all); void dm_ima_measure_on_table_clear(struct mapped_device *md, bool new_map); void dm_ima_measure_on_device_rename(struct mapped_device *md); +void dm_ima_measure_on_target_update(struct dm_target *ti); #else @@ -72,6 +73,7 @@ static inline void dm_ima_measure_on_device_resume(struct mapped_device *md, boo static inline void dm_ima_measure_on_device_remove(struct mapped_device *md, bool remove_all) {} static inline void dm_ima_measure_on_table_clear(struct mapped_device *md, bool new_map) {} static inline void dm_ima_measure_on_device_rename(struct mapped_device *md) {} +static inline void dm_ima_measure_on_target_update(struct dm_target *ti) {} #endif /* CONFIG_IMA */