From patchwork Fri Aug 28 20:27:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tushar Sugandhi X-Patchwork-Id: 11743715 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 2F8AD913 for ; Fri, 28 Aug 2020 20:27:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 118F920897 for ; Fri, 28 Aug 2020 20:27:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="TOZbhtLO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726649AbgH1U1V (ORCPT ); Fri, 28 Aug 2020 16:27:21 -0400 Received: from linux.microsoft.com ([13.77.154.182]:54142 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726386AbgH1U1P (ORCPT ); Fri, 28 Aug 2020 16:27:15 -0400 Received: from tusharsu-Ubuntu.lan (c-71-197-163-6.hsd1.wa.comcast.net [71.197.163.6]) by linux.microsoft.com (Postfix) with ESMTPSA id 65DB32056D2B; Fri, 28 Aug 2020 13:27:12 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 65DB32056D2B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1598646432; bh=NerDq3gdIlRcrRM8T8/D8y0TGEqJBJX6w3S5VPPAmp0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TOZbhtLOpA+EDT2LE1idyv2NPtZn3aGMbVFOnr2N6sBBiQe5TRspRzyZxGl6gSUnL Vi+gMGzGQQIBcneVJYixclOkxWAORci/4rm6JglgiYPFqTHvhFc65L8as4T5BZHbLB uZmQPx0uvkL+Nuu9bT/n2SvkrYnWcLhVO8V96WmU= From: Tushar Sugandhi To: zohar@linux.ibm.com, agk@redhat.com, snitzer@redhat.com, gmazyland@gmail.com Cc: tyhicks@linux.microsoft.com, sashal@kernel.org, jmorris@namei.org, nramas@linux.microsoft.com, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com Subject: [PATCH v3 2/2] dm-crypt: collect data and submit to DM to measure Date: Fri, 28 Aug 2020 13:27:00 -0700 Message-Id: <20200828202700.23086-3-tusharsu@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200828202700.23086-1-tusharsu@linux.microsoft.com> References: <20200828202700.23086-1-tusharsu@linux.microsoft.com> Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Currently, dm-crypt does not take advantage of IMA measuring capabilities, and ultimately the benefits of remote attestation. Measure various dm-crypt constructs by calling various device-mapper functions - dm_ima_*() that use IMA measuring capabilities. Implement ima_measure_dm_crypt_data() to measure various dm-crypt constructs. Ensure that ima_measure_dm_crypt_data() is non intrusive, i.e. failures in this function and the call-stack below should not affect the core functionality of dm-crypt. Register dm-crypt as supported data source for IMA measurement in ima.h. A demonstrative usage of above functionality on a system: If the IMA policy contains the following rule: measure func=CRITICAL_DATA critical_kernel_data_sources=dm-crypt template=ima-buf and, the following commands are used to setup a crypt target: #key="faf453b4ee938cff2f0d2c869a0b743f59125c0a37f5bcd8f1dbbd911a78abaa" #arg="'0 1953125 crypt aes-xts-plain64 " #arg="$arg $key 0 " #arg="$arg /dev/loop0 0 1 allow_discards'" #tgt_name="test-crypt" #cmd="dmsetup create $tgt_name --table $arg" #eval $cmd then, the IMA log at /sys/kernel/security/integrity/ima/ascii_runtime_measurements should contain the dm-crypt measurements. And, the following IMA log entry should be added in the IMA log, ima-buf sha1:039d8ff71918608d585adca3e5aab2e3f41f84d6 1598637500:520585536:dm-crypt:add_target 74695f6e756d5f646973636172645f62696f733d313b7065725f62696f5f646 174615f73697a653d3834383b646d7265715f73746172743d3136383b74666d 735f636f756e743d313b6f6e5f6469736b5f7461675f73697a653d303b696e7 46567726974795f69765f73697a653d303b696e746567726974795f7461675f 73697a653d303b69765f73697a653d31363b69765f6f66667365743d303b736 563746f725f73686966743d303b736563746f725f73697a653d3531323b666c 6167733d323b6369706865725f666c6167733d303b73746172743d303b6b657 95f6d61635f73697a653d303b6b65795f65787472615f73697a653d303b6b65 795f70617274733d313b6b65795f73697a653d33323b6369706865725f73747 2696e673d6165732d7874732d706c61696e36343b6465766963655f6e616d65 3d3235333a303b where, the ascii representation of the above data is: ti_num_discard_bios=1;per_bio_data_size=848;dmreq_start=168; tfms_count=1;on_disk_tag_size=0;integrity_iv_size=0; integrity_tag_size=0;iv_size=16;iv_offset=0;sector_shift=0; sector_size=512;flags=2;cipher_flags=0;start=0;key_mac_size=0; key_extra_size=0;key_parts=1;key_size=32; cipher_string=aes-xts-plain64;device_name=253:0; Some of the above values can be verified using: #dmsetup table --showkeys where, the output of the command should be similar to: test-crypt: 0 1953125 crypt aes-xts-plain64 faf453b4ee938cff2f0d2c869a0b743f59125c0a37f5bcd8f1dbbd911a78abaa 0 7:0 0 1 allow_discards Signed-off-by: Tushar Sugandhi --- drivers/md/dm-crypt.c | 171 +++++++++++++++++++++++++++++++++ security/integrity/ima/Kconfig | 3 +- security/integrity/ima/ima.h | 1 + 3 files changed, 173 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c index 148960721254..47fb2ce15211 100644 --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -2529,6 +2529,8 @@ static void crypt_dtr(struct dm_target *ti) ti->private = NULL; + dm_ima_exit_measurements(ti->type); + if (!cc) return; @@ -2991,6 +2993,167 @@ static int crypt_report_zones(struct dm_target *ti, #endif +#ifdef CONFIG_IMA +/* + * append integer values to dm-crypt specific data + * to be measured through IMA + */ +static int ima_append_num_values(struct dm_target *ti, + const char *key, + long long num_val) +{ + char *num_str = NULL; + int length = 0; + int r = 0; + + if (!ti || !key) { + r = -EINVAL; + goto error; + } + + length = snprintf(NULL, 0, "%lld", num_val); + num_str = kzalloc(length + 1, GFP_KERNEL); + if (!num_str) { + r = -ENOMEM; + goto error; + } + snprintf(num_str, length + 1, "%lld", num_val); + dm_ima_append_measurement_list(ti->type, + key, + (const void *)num_str, + length); + kzfree(num_str); + return r; +error: + DMERR("appending num values to IMA measurement list failed %d", r); + return r; +} +/* + * Measure dm-crypt specific data through IMA. + * It appends all the needed data to the list as a key-val pair using + * dm_ima_append_measurement_list() and internal ima_append_num_values(), + * and finally measures the list using dm_ima_finalize_and_measure(). + */ +static void ima_measure_dm_crypt_data(struct dm_target *ti, const char *desc) +{ + int r = 0; + struct crypt_config *cc = NULL; + const char *devname = dm_table_device_name(ti->table); + + if (!ti) { + r = -EINVAL; + goto out; + } + + cc = ti->private; + + if (devname) { + dm_ima_append_measurement_list(ti->type, + "device_name", + (const void *)devname, + strlen(devname)); + } + + if (cc->cipher_string) { + dm_ima_append_measurement_list(ti->type, + "cipher_string", + (const void *)cc->cipher_string, + strlen(cc->cipher_string)); + } + + if (cc->cipher_auth) { + dm_ima_append_measurement_list(ti->type, + "cipher_auth", + (const void *)cc->cipher_auth, + strlen(cc->cipher_auth)); + } + + r = ima_append_num_values(ti, "key_size", cc->key_size); + if (r) + goto out; + + r = ima_append_num_values(ti, "key_parts", cc->key_parts); + if (r) + goto out; + + r = ima_append_num_values(ti, "key_extra_size", cc->key_extra_size); + if (r) + goto out; + + r = ima_append_num_values(ti, "key_mac_size", cc->key_mac_size); + if (r) + goto out; + + r = ima_append_num_values(ti, "start", cc->start); + if (r) + goto out; + + r = ima_append_num_values(ti, "cipher_flags", cc->cipher_flags); + if (r) + goto out; + + r = ima_append_num_values(ti, "flags", cc->flags); + if (r) + goto out; + + r = ima_append_num_values(ti, "sector_size", cc->sector_size); + if (r) + goto out; + + r = ima_append_num_values(ti, "sector_shift", cc->sector_shift); + if (r) + goto out; + + r = ima_append_num_values(ti, "iv_offset", cc->iv_offset); + if (r) + goto out; + + r = ima_append_num_values(ti, "iv_size", cc->iv_size); + if (r) + goto out; + + r = ima_append_num_values(ti, "integrity_tag_size", cc->integrity_tag_size); + if (r) + goto out; + + r = ima_append_num_values(ti, "integrity_iv_size", cc->integrity_iv_size); + if (r) + goto out; + + r = ima_append_num_values(ti, "on_disk_tag_size", cc->on_disk_tag_size); + if (r) + goto out; + + r = ima_append_num_values(ti, "tfms_count", cc->tfms_count); + if (r) + goto out; + + r = ima_append_num_values(ti, "dmreq_start", cc->dmreq_start); + if (r) + goto out; + + r = ima_append_num_values(ti, "per_bio_data_size", cc->per_bio_data_size); + if (r) + goto out; + + r = ima_append_num_values(ti, "ti_num_discard_bios", + ti->num_discard_bios); + if (r) + goto out; + + dm_ima_finalize_and_measure(ti->type, desc, false); + return; + +out: + DMERR("IMA measurement of dm-crypt data failed %d", r); + +} +#else +static inline void ima_measure_dm_crypt_data(struct dm_target *ti, + const char *desc) {} +#endif /* CONFIG_IMA */ + + /* * Construct an encryption mapping: * [|:::] @@ -3186,6 +3349,10 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) ti->num_flush_bios = 1; + dm_ima_init_measurements(ti->type); + + ima_measure_dm_crypt_data(ti, "add_target"); + return 0; bad: @@ -3324,6 +3491,8 @@ static void crypt_postsuspend(struct dm_target *ti) struct crypt_config *cc = ti->private; set_bit(DM_CRYPT_SUSPENDED, &cc->flags); + + ima_measure_dm_crypt_data(ti, "post_suspend"); } static int crypt_preresume(struct dm_target *ti) @@ -3343,6 +3512,8 @@ static void crypt_resume(struct dm_target *ti) struct crypt_config *cc = ti->private; clear_bit(DM_CRYPT_SUSPENDED, &cc->flags); + + ima_measure_dm_crypt_data(ti, "resume"); } /* Message interface diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index 953314d145bb..ad643cc5aad4 100644 --- a/security/integrity/ima/Kconfig +++ b/security/integrity/ima/Kconfig @@ -324,8 +324,7 @@ config IMA_MEASURE_ASYMMETRIC_KEYS config IMA_QUEUE_EARLY_BOOT_DATA bool - depends on IMA_MEASURE_ASYMMETRIC_KEYS - depends on SYSTEM_TRUSTED_KEYRING + depends on (IMA_MEASURE_ASYMMETRIC_KEYS && SYSTEM_TRUSTED_KEYRING) || DM_CRYPT default y config IMA_SECURE_AND_OR_TRUSTED_BOOT diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 422fe833037d..bc922aa2ff92 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -230,6 +230,7 @@ struct modsig; #define __ima_supported_kernel_data_sources(source) \ source(MIN_SOURCE, min_source) \ + source(DM_CRYPT, dm-crypt) \ source(MAX_SOURCE, max_source) #define __ima_enum_stringify(ENUM, str) (#str),