From mboxrd@z Thu Jan 1 00:00:00 1970 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=-23.2 required=3.0 tests=BAYES_00,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_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 06A14C55164 for ; Sat, 12 Dec 2020 01:01:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E3FF22343E for ; Sat, 12 Dec 2020 01:01:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437683AbgLLAKf (ORCPT ); Fri, 11 Dec 2020 19:10:35 -0500 Received: from linux.microsoft.com ([13.77.154.182]:56300 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2437674AbgLLAK3 (ORCPT ); Fri, 11 Dec 2020 19:10:29 -0500 Received: from sequoia (162-237-133-238.lightspeed.rcsntx.sbcglobal.net [162.237.133.238]) by linux.microsoft.com (Postfix) with ESMTPSA id DFF8720B717A; Fri, 11 Dec 2020 16:09:45 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com DFF8720B717A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1607731786; bh=U9C7wFEM0d6l1NgBupTq6HaTsN/kw1IUPLplR/vR6TU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=U21UhiLVN4uIlwKtO7ebWoTljC0TAXxavjbGfMpsqE5hzFIm1G8bo8m+sIeV3LJDo y77iC1zg0yD/VO9reDjAQNCknPD3Js/KjmCy5r8STm/KUs2AhqlzcJRvcKf0b9t6XW htx7DiU7XpF2x0zYpxSjC4dOgVyjVJHybL6MewPQ= Date: Fri, 11 Dec 2020 18:09:44 -0600 From: Tyler Hicks To: Tushar Sugandhi Cc: zohar@linux.ibm.com, stephen.smalley.work@gmail.com, casey@schaufler-ca.com, agk@redhat.com, snitzer@redhat.com, gmazyland@gmail.com, paul@paul-moore.com, sashal@kernel.org, jmorris@namei.org, nramas@linux.microsoft.com, linux-integrity@vger.kernel.org, selinux@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com Subject: Re: [PATCH v8 2/8] IMA: add support to measure buffer data hash Message-ID: <20201212000944.GD4951@sequoia> References: <20201211235807.30815-1-tusharsu@linux.microsoft.com> <20201211235807.30815-3-tusharsu@linux.microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201211235807.30815-3-tusharsu@linux.microsoft.com> Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On 2020-12-11 15:58:01, Tushar Sugandhi wrote: > The original IMA buffer data measurement sizes were small (e.g. boot > command line), but the new buffer data measurement use cases have data > sizes that are a lot larger. Just as IMA measures the file data hash, > not the file data, IMA should similarly support the option for measuring > the hash of the buffer data. > > Measuring in-memory buffer-data/buffer-data-hash is different than > measuring file-data/file-data-hash. For the file, IMA stores the > measurements in both measurement log and the file's extended attribute - > which can later be used for appraisal as well. For buffer, the > measurements are only stored in the IMA log, since the buffer has no > extended attributes associated with it. > > Introduce a boolean parameter measure_buf_hash to support measuring > hash of a buffer, which would be much smaller, instead of the buffer > itself. > > Signed-off-by: Tushar Sugandhi Reviewed-by: Tyler Hicks Tyler > --- > security/integrity/ima/ima.h | 3 +- > security/integrity/ima/ima_appraise.c | 2 +- > security/integrity/ima/ima_asymmetric_keys.c | 2 +- > security/integrity/ima/ima_main.c | 38 +++++++++++++++++--- > security/integrity/ima/ima_queue_keys.c | 3 +- > 5 files changed, 39 insertions(+), 9 deletions(-) > > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h > index e5622ce8cbb1..fa3044a7539f 100644 > --- a/security/integrity/ima/ima.h > +++ b/security/integrity/ima/ima.h > @@ -268,7 +268,8 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file, > struct ima_template_desc *template_desc); > void process_buffer_measurement(struct inode *inode, const void *buf, int size, > const char *eventname, enum ima_hooks func, > - int pcr, const char *func_data); > + int pcr, const char *func_data, > + bool measure_buf_hash); > void ima_audit_measurement(struct integrity_iint_cache *iint, > const unsigned char *filename); > int ima_alloc_init_template(struct ima_event_data *event_data, > diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c > index 8361941ee0a1..46ffa38bab12 100644 > --- a/security/integrity/ima/ima_appraise.c > +++ b/security/integrity/ima/ima_appraise.c > @@ -352,7 +352,7 @@ int ima_check_blacklist(struct integrity_iint_cache *iint, > if ((rc == -EPERM) && (iint->flags & IMA_MEASURE)) > process_buffer_measurement(NULL, digest, digestsize, > "blacklisted-hash", NONE, > - pcr, NULL); > + pcr, NULL, false); > } > > return rc; > diff --git a/security/integrity/ima/ima_asymmetric_keys.c b/security/integrity/ima/ima_asymmetric_keys.c > index 1c68c500c26f..a74095793936 100644 > --- a/security/integrity/ima/ima_asymmetric_keys.c > +++ b/security/integrity/ima/ima_asymmetric_keys.c > @@ -60,5 +60,5 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key, > */ > process_buffer_measurement(NULL, payload, payload_len, > keyring->description, KEY_CHECK, 0, > - keyring->description); > + keyring->description, false); > } > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c > index e76ef4bfd0f4..0f8409d77602 100644 > --- a/security/integrity/ima/ima_main.c > +++ b/security/integrity/ima/ima_main.c > @@ -779,7 +779,7 @@ int ima_post_load_data(char *buf, loff_t size, > } > > /* > - * process_buffer_measurement - Measure the buffer to ima log. > + * process_buffer_measurement - Measure the buffer or the buffer data hash > * @inode: inode associated with the object being measured (NULL for KEY_CHECK) > * @buf: pointer to the buffer that needs to be added to the log. > * @size: size of buffer(in bytes). > @@ -787,12 +787,23 @@ int ima_post_load_data(char *buf, loff_t size, > * @func: IMA hook > * @pcr: pcr to extend the measurement > * @func_data: private data specific to @func, can be NULL. > + * @measure_buf_hash: measure buffer hash > * > - * Based on policy, the buffer is measured into the ima log. > + * Measure the buffer into the IMA log, and extend the @pcr. > + * > + * Determine what buffers are allowed to be measured, based on the policy rules > + * and the IMA hook passed using @func. > + * > + * Use @func_data, if provided, to match against the measurement policy rule > + * data for @func. > + * > + * If @measure_buf_hash is set to true - measure hash of the buffer data, > + * else measure the buffer data itself. > */ > void process_buffer_measurement(struct inode *inode, const void *buf, int size, > const char *eventname, enum ima_hooks func, > - int pcr, const char *func_data) > + int pcr, const char *func_data, > + bool measure_buf_hash) > { > int ret = 0; > const char *audit_cause = "ENOMEM"; > @@ -807,6 +818,8 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size, > struct ima_digest_data hdr; > char digest[IMA_MAX_DIGEST_SIZE]; > } hash = {}; > + char buf_hash[IMA_MAX_DIGEST_SIZE]; > + int buf_hash_len = hash_digest_size[ima_hash_algo]; > int violation = 0; > int action = 0; > u32 secid; > @@ -849,13 +862,27 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size, > goto out; > } > > + if (measure_buf_hash) { > + memcpy(buf_hash, hash.hdr.digest, buf_hash_len); > + > + ret = ima_calc_buffer_hash(buf_hash, buf_hash_len, > + iint.ima_hash); > + if (ret < 0) { > + audit_cause = "measure_buf_hash_error"; > + goto out; > + } > + > + event_data.buf = buf_hash; > + event_data.buf_len = buf_hash_len; > + } > + > ret = ima_alloc_init_template(&event_data, &entry, template); > if (ret < 0) { > audit_cause = "alloc_entry"; > goto out; > } > > - ret = ima_store_template(entry, violation, NULL, buf, pcr); > + ret = ima_store_template(entry, violation, NULL, event_data.buf, pcr); > if (ret < 0) { > audit_cause = "store_entry"; > ima_free_template_entry(entry); > @@ -890,7 +917,8 @@ void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) > return; > > process_buffer_measurement(file_inode(f.file), buf, size, > - "kexec-cmdline", KEXEC_CMDLINE, 0, NULL); > + "kexec-cmdline", KEXEC_CMDLINE, 0, NULL, > + false); > fdput(f); > } > > diff --git a/security/integrity/ima/ima_queue_keys.c b/security/integrity/ima/ima_queue_keys.c > index 69a8626a35c0..c2f2ad34f9b7 100644 > --- a/security/integrity/ima/ima_queue_keys.c > +++ b/security/integrity/ima/ima_queue_keys.c > @@ -162,7 +162,8 @@ void ima_process_queued_keys(void) > entry->payload_len, > entry->keyring_name, > KEY_CHECK, 0, > - entry->keyring_name); > + entry->keyring_name, > + false); > list_del(&entry->list); > ima_free_key_entry(entry); > } > -- > 2.17.1 >