From patchwork Fri May 20 14:26:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thore Sommer X-Patchwork-Id: 12856867 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 84DE2C433F5 for ; Fri, 20 May 2022 14:26:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237044AbiETO0W (ORCPT ); Fri, 20 May 2022 10:26:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34818 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236974AbiETO0T (ORCPT ); Fri, 20 May 2022 10:26:19 -0400 Received: from mo4-p01-ob.smtp.rzone.de (mo4-p01-ob.smtp.rzone.de [81.169.146.165]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7325B3524F for ; Fri, 20 May 2022 07:26:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1653056775; 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=0ZjTH9EydthIdiRbYOjbjiwaRe+7TWxB0BDThVI+jpU=; b=iSjK8sDbkxEKE2pOJbmajgoWFrOvwZ+AuOIAXmJH8pO7RIZZOKzb0999mF4lI3KBf/ yreQCdFurYfy7yniOjB79Ctb7fc3TD2HCyINFo5U29HOHF71oM44hNphoTopzBoIbjXU zZoWK30xj2Kt1xwfJJK1GB8GeVSB1sVZf4bTXwgyIqFL6eyNFMSKhDmePuRiloPGoad+ HN7vLzLT8iGPZZEaMZUAISjONcfj4/ZlcgHSWQKjUYAD9Utu/TB5AGIj5CsB8ClDKkl+ zqjvxMmud8PkLDp+zCXY3seZ971qhe/8BWoX9sYkZGeywLfT47OTA+EbZho2kPbyOv58 3X3Q== 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 47.42.2 DYNA|AUTH) with ESMTPSA id Y03eaey4KEQEQD5 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 20 May 2022 16:26:14 +0200 (CEST) From: Thore Sommer To: dm-devel@redhat.com, agk@redhat.com, snitzer@redhat.com, nramas@linux.microsoft.com Cc: linux-integrity@vger.kernel.org, Thore Sommer Subject: [PATCH 1/3] dm ima: allow targets to remeasure their table entry Date: Fri, 20 May 2022 16:26:03 +0200 Message-Id: <20220520142605.270625-2-public@thson.de> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220520142605.270625-1-public@thson.de> References: <20220520142605.270625-1-public@thson.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org The existing device mapper IMA measurements only measure the table content on target creation. This is fine for targets that do not change their table during runtime, but some targets like verity use the table to display state changes. Those changes are not visible through the existing device mapper integration. A new DM event "dm_target_update" is introduced for targets to remeasure their table entry. This event is intended to be used by targets that change their table entries to indicate potential security relevant information. This allows for a more complete Remote Attestation of device mapper targets. For example a verity target is never marked as corrupted during creation, because it only happens when a corrupted block is read. Using the new event the table entry change will be visible in the IMA log. In the event the dm version, device metadata and target data gets measured. The hash of the active table is not updated because it would require to rehash the whole table with all the other targets entries. Signed-off-by: Thore Sommer --- - v1: - do not initialize ima_buf with NULL - use return value of scnprintf for target_metadata_buf_len - rewrite target_index calculation to use less variables - remove unnecessary NULL check for ti2 drivers/md/dm-ima.c | 70 +++++++++++++++++++++++++++++++++++++++++++++ drivers/md/dm-ima.h | 2 ++ 2 files changed, 72 insertions(+) diff --git a/drivers/md/dm-ima.c b/drivers/md/dm-ima.c index 1842d3a958ef..bac217440853 100644 --- a/drivers/md/dm-ima.c +++ b/drivers/md/dm-ima.c @@ -750,3 +750,73 @@ 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, *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 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 == ti2) + break; + } + if (target_index == num_targets) + goto exit; + + target_metadata_buf_len = 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); + + 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 */ From patchwork Fri May 20 14:26:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thore Sommer X-Patchwork-Id: 12856868 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 34496C433EF for ; Fri, 20 May 2022 14:26:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238648AbiETO0Y (ORCPT ); Fri, 20 May 2022 10:26:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34918 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237079AbiETO0V (ORCPT ); Fri, 20 May 2022 10:26:21 -0400 Received: from mo4-p01-ob.smtp.rzone.de (mo4-p01-ob.smtp.rzone.de [85.215.255.52]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A8ED35244 for ; Fri, 20 May 2022 07:26:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1653056778; 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=TKVzWMWh/iK70Mm9HetHCSrG8L7/6BKdS9Anokzny/s=; b=sEW0jEtBXG3OqN+uMNTOB97hIMvy3knmi2GY2oad5jFf1+MNODw8gHu/8rR+gAQMZZ fnnlp5ZbSTO8AaNRUAwk00HcUDXymRyBLKXs9bno5NsdvE1Ix52sjfb6Q/zNq/QiSS7E 5rNtfqRnWlCzZWksrFGAv2iqrdGrOIPjfLxIZsd1ro0g+m1gNUNkNSrddG10SDydBUjn J+Jri+zRazE2DmWFsSrJ0Nt0IQX0BuRUKRAqm1Wui3IeEY+ioa8AVgowRlmXNA2KBX2A Ygeqk3YUGHZ6DTqTx/4b/7mNexn+UjuA6jjGKTc5IlMcKWJIQZoamveOJwtOAUwWFDDL pDXg== 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 47.42.2 DYNA|AUTH) with ESMTPSA id Y03eaey4KEQHQD6 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 20 May 2022 16:26:17 +0200 (CEST) From: Thore Sommer To: dm-devel@redhat.com, agk@redhat.com, snitzer@redhat.com, nramas@linux.microsoft.com Cc: linux-integrity@vger.kernel.org, Thore Sommer Subject: [PATCH 2/3] dm verity: add support for IMA target update event Date: Fri, 20 May 2022 16:26:04 +0200 Message-Id: <20220520142605.270625-3-public@thson.de> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220520142605.270625-1-public@thson.de> References: <20220520142605.270625-1-public@thson.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On first corruption the verity targets triggers a "dm_target_update" event. This allows other systems to detect the corruption via IMA instead of manually querying the table. The corruption cannot be detected using the other IMA measurements because "dm_table_load" only measures the table content during target creation. Using the new "dm_target_update" remeasures the target table entries during runtime. The event is only triggered if the target was not corrupted before because verity_handle_err(..) is still called when the target is corrupted and the IMA log should only contain an entry when the table changed. Signed-off-by: Thore Sommer --- - v1: rewrite check to not use an extra variable drivers/md/dm-verity-target.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c index 80133aae0db3..5133c2274057 100644 --- a/drivers/md/dm-verity-target.c +++ b/drivers/md/dm-verity-target.c @@ -16,6 +16,7 @@ #include "dm-verity.h" #include "dm-verity-fec.h" #include "dm-verity-verify-sig.h" +#include "dm-ima.h" #include #include #include @@ -219,8 +220,13 @@ static int verity_handle_err(struct dm_verity *v, enum verity_block_type type, const char *type_str = ""; struct mapped_device *md = dm_table_get_md(v->ti->table); - /* Corruption should be visible in device status in all modes */ - v->hash_failed = 1; + /* Only change and measure change if not already corrupted */ + if (!v->hash_failed) { + /* Corruption should be visible in device status in all modes */ + v->hash_failed = 1; + /* After the state has changed remeasure target table */ + dm_ima_measure_on_target_update(v->ti); + } if (v->corrupted_errs >= DM_VERITY_MAX_CORRUPTED_ERRS) goto out; From patchwork Fri May 20 14:26:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thore Sommer X-Patchwork-Id: 12856869 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 6796BC433FE for ; Fri, 20 May 2022 14:26:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233449AbiETO00 (ORCPT ); Fri, 20 May 2022 10:26:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35046 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237927AbiETO0Y (ORCPT ); Fri, 20 May 2022 10:26:24 -0400 Received: from mo4-p02-ob.smtp.rzone.de (mo4-p02-ob.smtp.rzone.de [85.215.255.84]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E80873524F for ; Fri, 20 May 2022 07:26:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1653056779; 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=B94K503l7XtRdtAMd+10Ls9LaOI2UKAvLlbP676gbeI=; b=c5X3iv5yvRNE9cBsU5mPH5FkkFrmPojx00wC/0g7nzQJ6HXyH2q4sZci91ibHedY4P sIhBc8OaYaRShuxhQQACybSyQYmqUhxqbqSANGk4S7PPbqCXB+HXB0b3N12gT/WBlnIg 59ETqFDsHMyt90CgBo7vqYuOUGtvH8opv4EWjGRK2qmsfP43BTscNSiDtpmB8ep/kp7M ZxhenEzLuiqPK8UZEpyXNDqgwllkkgGh8co3G0puefrseGlxmGW9XwIns4nzaazTh3Ei t1xjLWAzA1JpyRPJctkgiNH5BOBiijwxWqb6s60SkN8YfrLan3NSxXI+Vi1FceAkCHef CMag== 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 47.42.2 DYNA|AUTH) with ESMTPSA id Y03eaey4KEQIQD8 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 20 May 2022 16:26:18 +0200 (CEST) From: Thore Sommer To: dm-devel@redhat.com, agk@redhat.com, snitzer@redhat.com, nramas@linux.microsoft.com Cc: linux-integrity@vger.kernel.org, Thore Sommer Subject: [PATCH 3/3] dm ima: add documentation target update event Date: Fri, 20 May 2022 16:26:05 +0200 Message-Id: <20220520142605.270625-4-public@thson.de> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220520142605.270625-1-public@thson.de> References: <20220520142605.270625-1-public@thson.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org The dm_target_update event can be triggered by targets to remeasure their state to reflect that change also in IMA. This is event is currently only supported by verity. Signed-off-by: Thore Sommer --- .../admin-guide/device-mapper/dm-ima.rst | 33 +++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/Documentation/admin-guide/device-mapper/dm-ima.rst b/Documentation/admin-guide/device-mapper/dm-ima.rst index a4aa50a828e0..ac9418ea99d3 100644 --- a/Documentation/admin-guide/device-mapper/dm-ima.rst +++ b/Documentation/admin-guide/device-mapper/dm-ima.rst @@ -93,6 +93,7 @@ Following device state changes will trigger IMA measurements: #. Device remove #. Table clear #. Device rename + #. Target update 1. Table load: --------------- @@ -321,6 +322,38 @@ The IMA measurement log has the following format for 'dm_device_rename': new_name=linear\=2,new_uuid=1234-5678; current_device_capacity=1024; +6. Target update: +------------------ +When a target changes updates its table it can trigger an remeasurement of that table. + +This is currently only implemented for 'verity' targets to detect measure corruption occurrences. +Note that the active table hash of the device does not get updated. + +The IMA measurement log has the following format for 'dm_target_update': + +:: + + EVENT_NAME := "dm_target_update" + EVENT_DATA := ";" ";" ";" + + dm_version_str := As described in the 'Table load' section above. + device_active_metadata := Device metadata that reflects the currently loaded active table. + The format is same as 'device_metadata' described in the 'Table load' section above. + target_data_row + E.g: if a verity device gets corrupted then IMA ASCII measurement log will have an entry with: + (converted from ASCII to text for readability) + + 10 1cc9c660afb7fddd1b7167f0c4e997ebca8b1c09 ima-buf sha256:e991f7692724257701c8e652682bd3246837ed2d655407b9e9f5a5b469e6c75b + dm_target_update + dm_version=4.45.0; + name=test,uuid=CRYPT-VERITY-e0d2a85fd61e41238174adaa32d296fe-test,major=253,minor=0,minor_count=1,num_targets=1; + target_index=0,target_begin=0,target_len=8,target_name=verity,target_version=1.8.0,hash_failed=C, + verity_version=1,data_device_name=7:1,hash_device_name=7:0,verity_algorithm=sha256, + root_digest=8c2eff0b45fc9815b94350f7a913683ef34085c734229bcf1345c31b07ac61b8, + salt=63010b7c63e28e6929a2f020dc71c97a0660a9f377a83c674a62feb01c5ca6b3, + ignore_zero_blocks=n,check_at_most_once=n; + + Supported targets: ==================