From patchwork Thu Nov 19 23:26:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tushar Sugandhi X-Patchwork-Id: 11919175 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=-26.2 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_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 3977EC83011 for ; Thu, 19 Nov 2020 23:26:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DE6E422255 for ; Thu, 19 Nov 2020 23:26:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="pXdgi5Xo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727168AbgKSX0j (ORCPT ); Thu, 19 Nov 2020 18:26:39 -0500 Received: from linux.microsoft.com ([13.77.154.182]:32904 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726123AbgKSX0X (ORCPT ); Thu, 19 Nov 2020 18:26:23 -0500 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 B07E620B7186; Thu, 19 Nov 2020 15:26:20 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com B07E620B7186 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1605828381; bh=DvWlNgw3wAZG8ocsMzrR2Nhg/VhWejyYflhKUBcZg7M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pXdgi5XoK1m7YSE6YCWuAxJyUCzwkNd3yclXH5TbwpMu1Gx7E4nSHHAMx5FdZGQiM wbLPQZJAu22/iuqucEWVEd7Nno94FzRvMBNJtgq0+pLVF78VDs5d6Gfka+VteOiF7v ICRRPWBs3u7HvE2ard0k0aKXvtRKAcefjL1U1hAI= From: Tushar Sugandhi To: 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 Cc: tyhicks@linux.microsoft.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: [PATCH v6 1/8] IMA: generalize keyring specific measurement constructs Date: Thu, 19 Nov 2020 15:26:04 -0800 Message-Id: <20201119232611.30114-2-tusharsu@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201119232611.30114-1-tusharsu@linux.microsoft.com> References: <20201119232611.30114-1-tusharsu@linux.microsoft.com> Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org IMA functions such as ima_match_keyring(), process_buffer_measurement(), ima_match_policy() etc. handle data specific to keyrings. Currently, these constructs are not generic to handle any func specific data. This makes it harder to extend them without code duplication. Refactor the keyring specific measurement constructs to be generic and reusable in other measurement scenarios. Signed-off-by: Tushar Sugandhi --- security/integrity/ima/ima.h | 6 ++-- security/integrity/ima/ima_api.c | 6 ++-- security/integrity/ima/ima_main.c | 6 ++-- security/integrity/ima/ima_policy.c | 49 ++++++++++++++++++----------- 4 files changed, 40 insertions(+), 27 deletions(-) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 8e8b1e3cb847..e5622ce8cbb1 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -256,7 +256,7 @@ static inline void ima_process_queued_keys(void) {} int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid, int mask, enum ima_hooks func, int *pcr, struct ima_template_desc **template_desc, - const char *keyring); + const char *func_data); int ima_must_measure(struct inode *inode, int mask, enum ima_hooks func); int ima_collect_measurement(struct integrity_iint_cache *iint, struct file *file, void *buf, loff_t size, @@ -268,7 +268,7 @@ 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 *keyring); + int pcr, const char *func_data); void ima_audit_measurement(struct integrity_iint_cache *iint, const unsigned char *filename); int ima_alloc_init_template(struct ima_event_data *event_data, @@ -284,7 +284,7 @@ const char *ima_d_path(const struct path *path, char **pathbuf, char *filename); int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid, enum ima_hooks func, int mask, int flags, int *pcr, struct ima_template_desc **template_desc, - const char *keyring); + const char *func_data); void ima_init_policy(void); void ima_update_policy(void); void ima_update_policy_flag(void); diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index 4f39fb93f278..af218babd198 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -170,7 +170,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename, * @func: caller identifier * @pcr: pointer filled in if matched measure policy sets pcr= * @template_desc: pointer filled in if matched measure policy sets template= - * @keyring: keyring name used to determine the action + * @func_data: private data specific to @func, can be NULL. * * The policy is defined in terms of keypairs: * subj=, obj=, type=, func=, mask=, fsmagic= @@ -186,14 +186,14 @@ void ima_add_violation(struct file *file, const unsigned char *filename, int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid, int mask, enum ima_hooks func, int *pcr, struct ima_template_desc **template_desc, - const char *keyring) + const char *func_data) { int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE | IMA_HASH; flags &= ima_policy_flag; return ima_match_policy(inode, cred, secid, func, mask, flags, pcr, - template_desc, keyring); + template_desc, func_data); } /* diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index bc8c9fdb20a8..2691ce894189 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -786,13 +786,13 @@ int ima_post_load_data(char *buf, loff_t size, * @eventname: event name to be used for the buffer entry. * @func: IMA hook * @pcr: pcr to extend the measurement - * @keyring: keyring name to determine the action to be performed + * @func_data: private data specific to @func, can be NULL. * * Based on policy, the buffer is measured into the ima log. */ void process_buffer_measurement(struct inode *inode, const void *buf, int size, const char *eventname, enum ima_hooks func, - int pcr, const char *keyring) + int pcr, const char *func_data) { int ret = 0; const char *audit_cause = "ENOMEM"; @@ -831,7 +831,7 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size, if (func) { security_task_getsecid(current, &secid); action = ima_get_action(inode, current_cred(), secid, 0, func, - &pcr, &template, keyring); + &pcr, &template, func_data); if (!(action & IMA_MEASURE)) return; } diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 823a0c1379cb..25419c7ff50b 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -453,30 +453,44 @@ int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event, } /** - * ima_match_keyring - determine whether the keyring matches the measure rule - * @rule: a pointer to a rule - * @keyring: name of the keyring to match against the measure rule + * ima_match_rule_data - determine whether the given func_data matches + * the measure rule data + * @rule: IMA policy rule + * @func_data: data to match against the measure rule data * @cred: a pointer to a credentials structure for user validation * - * Returns true if keyring matches one in the rule, false otherwise. + * Returns true if func_data matches one in the rule, false otherwise. */ -static bool ima_match_keyring(struct ima_rule_entry *rule, - const char *keyring, const struct cred *cred) +static bool ima_match_rule_data(struct ima_rule_entry *rule, + const char *func_data, + const struct cred *cred) { + const struct ima_rule_opt_list *opt_list = NULL; bool matched = false; size_t i; if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid)) return false; - if (!rule->keyrings) - return true; + switch (rule->func) { + case KEY_CHECK: + if (!rule->keyrings) + return true; + else + opt_list = rule->keyrings; + break; + default: + break; + } - if (!keyring) + if (!func_data) + return false; + + if (!opt_list) return false; - for (i = 0; i < rule->keyrings->count; i++) { - if (!strcmp(rule->keyrings->items[i], keyring)) { + for (i = 0; i < opt_list->count; i++) { + if (!strcmp(opt_list->items[i], func_data)) { matched = true; break; } @@ -493,20 +507,20 @@ static bool ima_match_keyring(struct ima_rule_entry *rule, * @secid: the secid of the task to be validated * @func: LIM hook identifier * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC) - * @keyring: keyring name to check in policy for KEY_CHECK func + * @func_data: private data specific to @func, can be NULL. * * Returns true on rule match, false on failure. */ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode, const struct cred *cred, u32 secid, enum ima_hooks func, int mask, - const char *keyring) + const char *func_data) { int i; if (func == KEY_CHECK) { return (rule->flags & IMA_FUNC) && (rule->func == func) && - ima_match_keyring(rule, keyring, cred); + ima_match_rule_data(rule, func_data, cred); } if ((rule->flags & IMA_FUNC) && (rule->func != func && func != POST_SETATTR)) @@ -610,8 +624,7 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func) * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC) * @pcr: set the pcr to extend * @template_desc: the template that should be used for this rule - * @keyring: the keyring name, if given, to be used to check in the policy. - * keyring can be NULL if func is anything other than KEY_CHECK. + * @func_data: private data specific to @func, can be NULL. * * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type) * conditions. @@ -623,7 +636,7 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func) int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid, enum ima_hooks func, int mask, int flags, int *pcr, struct ima_template_desc **template_desc, - const char *keyring) + const char *func_data) { struct ima_rule_entry *entry; int action = 0, actmask = flags | (flags << 1); @@ -638,7 +651,7 @@ int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid, continue; if (!ima_match_rules(entry, inode, cred, secid, func, mask, - keyring)) + func_data)) continue; action |= entry->flags & IMA_ACTION_FLAGS; From patchwork Thu Nov 19 23:26:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tushar Sugandhi X-Patchwork-Id: 11919173 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=-26.2 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_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=ham 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 60372C71155 for ; Thu, 19 Nov 2020 23:26:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 16E6422202 for ; Thu, 19 Nov 2020 23:26:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="GdZ7ApAs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727159AbgKSX0i (ORCPT ); Thu, 19 Nov 2020 18:26:38 -0500 Received: from linux.microsoft.com ([13.77.154.182]:32916 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726321AbgKSX0X (ORCPT ); Thu, 19 Nov 2020 18:26:23 -0500 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 5F68420B718A; Thu, 19 Nov 2020 15:26:21 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 5F68420B718A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1605828381; bh=PXbNyCbxOoJtUP5x1YOdRIJKlNWgp0WUhgEJ43F3rZk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GdZ7ApAsBoM3+YsL3CVBfZTNkonwVXkLGpKr+Q3BKPeCsury3BmupmADP+UAxqXGt FLsjI3yaSpMXzc11wRKW9lo8M0XPCzevjCsvXnolcunrTKdjZKVJGUFfoIczh1euLa f6JCBHkbyH1tNoynzLNQWOghzYeY5JpnFsC94jRE= From: Tushar Sugandhi To: 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 Cc: tyhicks@linux.microsoft.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: [PATCH v6 2/8] IMA: add support to measure buffer data hash Date: Thu, 19 Nov 2020 15:26:05 -0800 Message-Id: <20201119232611.30114-3-tusharsu@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201119232611.30114-1-tusharsu@linux.microsoft.com> References: <20201119232611.30114-1-tusharsu@linux.microsoft.com> Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org 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 --- 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 | 36 +++++++++++++++++--- security/integrity/ima/ima_queue_keys.c | 3 +- 5 files changed, 38 insertions(+), 8 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 3dd8c2e4314e..be64c0bf62a7 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -347,7 +347,7 @@ 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 2691ce894189..f3501bdd1035 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; @@ -849,6 +862,20 @@ 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"; @@ -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); } From patchwork Thu Nov 19 23:26:06 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tushar Sugandhi X-Patchwork-Id: 11919169 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=-26.2 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_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 7ECAAC64E69 for ; Thu, 19 Nov 2020 23:26:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 20DCE22255 for ; Thu, 19 Nov 2020 23:26:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="DEMXViUx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727082AbgKSX01 (ORCPT ); Thu, 19 Nov 2020 18:26:27 -0500 Received: from linux.microsoft.com ([13.77.154.182]:32934 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726325AbgKSX0Y (ORCPT ); Thu, 19 Nov 2020 18:26:24 -0500 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 15AC020B71D2; Thu, 19 Nov 2020 15:26:22 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 15AC020B71D2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1605828382; bh=brA+6A2QE6Q+exvSYts5b4erozOos8EsHZx2T5mbmxk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DEMXViUxw32NXqk9Z2DAXjqH1mhmO4ikAxxWie3kHkBVwj3/QNrLjgf6ECGUyVWEc cY244SBX4h8WSB/9Z+ZQYzprjf7Qvw80MNRJa+uZ6uaK6BmDIs4c+FLlF49R+6Md2s GgtMycxQ3NSFcTKXNnYKdcE6YViYjWmBnXJSUVSc= From: Tushar Sugandhi To: 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 Cc: tyhicks@linux.microsoft.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: [PATCH v6 3/8] IMA: define a hook to measure kernel integrity critical data Date: Thu, 19 Nov 2020 15:26:06 -0800 Message-Id: <20201119232611.30114-4-tusharsu@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201119232611.30114-1-tusharsu@linux.microsoft.com> References: <20201119232611.30114-1-tusharsu@linux.microsoft.com> Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org IMA provides capabilities to measure file data, and in-memory buffer data. However, currently, IMA does not provide a generic function for kernel subsystems to measure the integrity critical data. Kernel integrity critical data can be defined as the in-memory kernel data which if accidentally or maliciously altered, can compromise the integrity of the system. Examples of critical data would be kernel in-memory r/o structures, hash of the memory structures, or data that represents a linux kernel subsystem state change. Define a new IMA hook named ima_measure_critical_data to measure kernel integrity critical data. Signed-off-by: Tushar Sugandhi --- Documentation/ABI/testing/ima_policy | 2 +- include/linux/ima.h | 6 +++++ security/integrity/ima/ima.h | 1 + security/integrity/ima/ima_api.c | 2 +- security/integrity/ima/ima_main.c | 36 ++++++++++++++++++++++++++++ security/integrity/ima/ima_policy.c | 2 ++ 6 files changed, 47 insertions(+), 2 deletions(-) diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index e35263f97fc1..6ec7daa87cba 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -32,7 +32,7 @@ Description: func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK]MODULE_CHECK] [FIRMWARE_CHECK] [KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK] - [KEXEC_CMDLINE] [KEY_CHECK] + [KEXEC_CMDLINE] [KEY_CHECK] [CRITICAL_DATA] mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND] [[^]MAY_EXEC] fsmagic:= hex value diff --git a/include/linux/ima.h b/include/linux/ima.h index 8fa7bcfb2da2..9911a6e496b6 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -30,6 +30,9 @@ extern int ima_post_read_file(struct file *file, void *buf, loff_t size, extern void ima_post_path_mknod(struct dentry *dentry); extern int ima_file_hash(struct file *file, char *buf, size_t buf_size); extern void ima_kexec_cmdline(int kernel_fd, const void *buf, int size); +extern void ima_measure_critical_data(const char *event_name, + const void *buf, int buf_len, + bool measure_buf_hash); #ifdef CONFIG_IMA_KEXEC extern void ima_add_kexec_buffer(struct kimage *image); @@ -116,6 +119,9 @@ static inline int ima_file_hash(struct file *file, char *buf, size_t buf_size) } static inline void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) {} +static inline void ima_measure_critical_data(const char *event_name, + const void *buf, int buf_len, + bool measure_buf_hash) {} #endif /* CONFIG_IMA */ #ifndef CONFIG_IMA_KEXEC diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index fa3044a7539f..7d9deda6a8b3 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -201,6 +201,7 @@ static inline unsigned int ima_hash_key(u8 *digest) hook(POLICY_CHECK, policy) \ hook(KEXEC_CMDLINE, kexec_cmdline) \ hook(KEY_CHECK, key) \ + hook(CRITICAL_DATA, critical_data) \ hook(MAX_CHECK, none) #define __ima_hook_enumify(ENUM, str) ENUM, diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index af218babd198..9917e1730cb6 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -176,7 +176,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename, * subj=, obj=, type=, func=, mask=, fsmagic= * subj,obj, and type: are LSM specific. * func: FILE_CHECK | BPRM_CHECK | CREDS_CHECK | MMAP_CHECK | MODULE_CHECK - * | KEXEC_CMDLINE | KEY_CHECK + * | KEXEC_CMDLINE | KEY_CHECK | CRITICAL_DATA * mask: contains the permission mask * fsmagic: hex value * diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index f3501bdd1035..7661f09569f3 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -922,6 +922,42 @@ void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) fdput(f); } +/** + * ima_measure_critical_data - measure kernel integrity critical data + * @event_name: event name to be used for the buffer entry + * @buf: pointer to buffer containing data to measure + * @buf_len: length of buffer(in bytes) + * @measure_buf_hash: measure buffer hash + * + * Measure the kernel subsystem data, critical to the integrity of the kernel, + * into the IMA log and extend the @pcr. + * + * Use @event_name to describe the state/buffer data change. + * Examples of critical data (buf) could be kernel in-memory r/o structures, + * hash of the memory structures, or data that represents subsystem state + * change. + * + * If @measure_buf_hash is set to true - measure hash of the buffer data, + * else measure the buffer data itself. + * measure_buf_hash can be used to save space, if the data being measured + * is too large. + * + * The data (buf) can only be measured, not appraised. + */ +void ima_measure_critical_data(const char *event_name, + const void *buf, int buf_len, + bool measure_buf_hash) +{ + if (!event_name || !buf || !buf_len) { + pr_err("Invalid arguments passed to %s().\n", __func__); + return; + } + + process_buffer_measurement(NULL, buf, buf_len, event_name, + CRITICAL_DATA, 0, NULL, + measure_buf_hash); +} + static int __init init_ima(void) { int error; diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 25419c7ff50b..2a0c0603626e 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -1251,6 +1251,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) && strcmp(args[0].from, "KEY_CHECK") == 0) entry->func = KEY_CHECK; + else if (strcmp(args[0].from, "CRITICAL_DATA") == 0) + entry->func = CRITICAL_DATA; else result = -EINVAL; if (!result) From patchwork Thu Nov 19 23:26:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tushar Sugandhi X-Patchwork-Id: 11919165 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=-26.2 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_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 B7A66C63777 for ; Thu, 19 Nov 2020 23:26:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5FD3D2222F for ; Thu, 19 Nov 2020 23:26:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="evICjJiY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727098AbgKSX01 (ORCPT ); Thu, 19 Nov 2020 18:26:27 -0500 Received: from linux.microsoft.com ([13.77.154.182]:32948 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727060AbgKSX0Y (ORCPT ); Thu, 19 Nov 2020 18:26:24 -0500 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 B8C1E20B7125; Thu, 19 Nov 2020 15:26:22 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com B8C1E20B7125 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1605828383; bh=sxVlLAkqjda0ZXj26t6BGZjCQWun9IH/OvCSStwtKOs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=evICjJiYyEEAVnbZPLvH2k3cp2ZId1S4M7yN1pvKJnzRTwjpVmtENHoyn1Sov2Lwv 0zO/bW/WET+7WOMSQZKYOKOeK0peizS6Yh73HfWylcBoXJ27xXOM1Ydt2IhCU9ygpO cttU8Nfnxf8HKu4zYCr/qccZ4CO3J7jEtAHJTsLM= From: Tushar Sugandhi To: 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 Cc: tyhicks@linux.microsoft.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: [PATCH v6 4/8] IMA: add policy rule to measure critical data Date: Thu, 19 Nov 2020 15:26:07 -0800 Message-Id: <20201119232611.30114-5-tusharsu@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201119232611.30114-1-tusharsu@linux.microsoft.com> References: <20201119232611.30114-1-tusharsu@linux.microsoft.com> Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org A new IMA policy rule is needed for the IMA hook ima_measure_critical_data() and the corresponding func CRITICAL_DATA for measuring the input buffer. The policy rule should ensure the buffer would get measured only when the policy rule allows the action. The policy rule should also support the necessary constraints (flags etc.) for integrity critical buffer data measurements. Add a policy rule to define the constraints for restricting integrity critical data measurements. Signed-off-by: Tushar Sugandhi --- security/integrity/ima/ima_policy.c | 35 +++++++++++++++++++++++++---- 1 file changed, 31 insertions(+), 4 deletions(-) diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 2a0c0603626e..583be7674f3e 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -34,6 +34,7 @@ #define IMA_PCR 0x0100 #define IMA_FSNAME 0x0200 #define IMA_KEYRINGS 0x0400 +#define IMA_DATA_SOURCES 0x0800 #define UNKNOWN 0 #define MEASURE 0x0001 /* same as IMA_MEASURE */ @@ -85,6 +86,7 @@ struct ima_rule_entry { } lsm[MAX_LSM_RULES]; char *fsname; struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */ + struct ima_rule_opt_list *data_sources; /* Measure data from these sources */ struct ima_template_desc *template; }; @@ -479,6 +481,12 @@ static bool ima_match_rule_data(struct ima_rule_entry *rule, else opt_list = rule->keyrings; break; + case CRITICAL_DATA: + if (!rule->data_sources) + return true; + else + opt_list = rule->data_sources; + break; default: break; } @@ -518,13 +526,19 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode, { int i; - if (func == KEY_CHECK) { - return (rule->flags & IMA_FUNC) && (rule->func == func) && - ima_match_rule_data(rule, func_data, cred); - } if ((rule->flags & IMA_FUNC) && (rule->func != func && func != POST_SETATTR)) return false; + + switch (func) { + case KEY_CHECK: + case CRITICAL_DATA: + return ((rule->func == func) && + ima_match_rule_data(rule, func_data, cred)); + default: + break; + } + if ((rule->flags & IMA_MASK) && (rule->mask != mask && func != POST_SETATTR)) return false; @@ -1119,6 +1133,19 @@ static bool ima_validate_rule(struct ima_rule_entry *entry) if (ima_rule_contains_lsm_cond(entry)) return false; + break; + case CRITICAL_DATA: + if (entry->action & ~(MEASURE | DONT_MEASURE)) + return false; + + if (!(entry->flags & IMA_DATA_SOURCES) || + (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_PCR | + IMA_DATA_SOURCES))) + return false; + + if (ima_rule_contains_lsm_cond(entry)) + return false; + break; default: return false; From patchwork Thu Nov 19 23:26:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tushar Sugandhi X-Patchwork-Id: 11919163 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=-26.2 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_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=ham 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 CF1E0C6379D for ; Thu, 19 Nov 2020 23:26:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6CEB422202 for ; Thu, 19 Nov 2020 23:26:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="Mhf5msVa" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727107AbgKSX02 (ORCPT ); Thu, 19 Nov 2020 18:26:28 -0500 Received: from linux.microsoft.com ([13.77.154.182]:32966 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726118AbgKSX0Y (ORCPT ); Thu, 19 Nov 2020 18:26:24 -0500 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 5B0E520B717A; Thu, 19 Nov 2020 15:26:23 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 5B0E520B717A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1605828383; bh=t/dotX4hyXMbNebGiOo5pLB/No3MOl4tkzd9roUuSGQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Mhf5msVadztTufeYWK95qnpkNHKuYsAQ59m6f1074edhFoJcpfFX5dt01ceG1vkl5 1sJ8MTx9vj9eZcyYaQLyjgl8cgn64K/xB9QHfD2eUJQBYMrj+aOkuhwZoWQ8sM2Jc9 Ee2Bzszyzhfezk9GEOf+5UAJ9bAhVwZIGWa4b63o= From: Tushar Sugandhi To: 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 Cc: tyhicks@linux.microsoft.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: [PATCH v6 5/8] IMA: extend policy to add data sources as a critical data measurement constraint Date: Thu, 19 Nov 2020 15:26:08 -0800 Message-Id: <20201119232611.30114-6-tusharsu@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201119232611.30114-1-tusharsu@linux.microsoft.com> References: <20201119232611.30114-1-tusharsu@linux.microsoft.com> Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org System administrators should be able to limit which kernel subsystems they want to measure the critical data for. To enable that, an IMA policy condition to choose specific kernel subsystems is needed. This policy condition would constrain the measurement of the critical data to the given kernel subsystems. Add a new IMA policy condition - "data_sources:=" to the IMA func CRITICAL_DATA to allow measurement of various kernel subsystems. This policy condition would enable the system administrators to restrict the measurement to the subsystems listed in "data_sources:=". Limit the measurement to the subsystems that are specified in the IMA policy - CRITICAL_DATA+"data_sources:=". If "data_sources:=" is not provided with the func CRITICAL_DATA, the data from all the supported kernel subsystems is measured. Signed-off-by: Tushar Sugandhi --- Documentation/ABI/testing/ima_policy | 4 ++++ security/integrity/ima/ima_policy.c | 27 ++++++++++++++++++++++++++- 2 files changed, 30 insertions(+), 1 deletion(-) diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 6ec7daa87cba..ee60442a41cd 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -52,6 +52,10 @@ Description: template:= name of a defined IMA template type (eg, ima-ng). Only valid when action is "measure". pcr:= decimal value + data_sources:= list of kernel subsystems that contain + kernel in-memory data critical to the integrity of the kernel. + Only valid when action is "measure" and func is + CRITICAL_DATA. default policy: # PROC_SUPER_MAGIC diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 583be7674f3e..c9e52dab0638 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -934,7 +934,7 @@ enum { Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt, Opt_appraise_type, Opt_appraise_flag, Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings, - Opt_err + Opt_data_sources, Opt_err }; static const match_table_t policy_tokens = { @@ -971,6 +971,7 @@ static const match_table_t policy_tokens = { {Opt_pcr, "pcr=%s"}, {Opt_template, "template=%s"}, {Opt_keyrings, "keyrings=%s"}, + {Opt_data_sources, "data_sources=%s"}, {Opt_err, NULL} }; @@ -1350,6 +1351,24 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) entry->flags |= IMA_KEYRINGS; break; + case Opt_data_sources: + ima_log_string(ab, "data_sources", + args[0].from); + + if (entry->data_sources) { + result = -EINVAL; + break; + } + + entry->data_sources = ima_alloc_rule_opt_list(args); + if (IS_ERR(entry->data_sources)) { + result = PTR_ERR(entry->data_sources); + entry->data_sources = NULL; + break; + } + + entry->flags |= IMA_DATA_SOURCES; + break; case Opt_fsuuid: ima_log_string(ab, "fsuuid", args[0].from); @@ -1730,6 +1749,12 @@ int ima_policy_show(struct seq_file *m, void *v) seq_puts(m, " "); } + if (entry->flags & IMA_DATA_SOURCES) { + seq_puts(m, "data_sources="); + ima_show_rule_opt_list(m, entry->data_sources); + seq_puts(m, " "); + } + if (entry->flags & IMA_PCR) { snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr); seq_printf(m, pt(Opt_pcr), tbuf); From patchwork Thu Nov 19 23:26:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tushar Sugandhi X-Patchwork-Id: 11919167 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=-26.2 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_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 E78F3C64EBC for ; Thu, 19 Nov 2020 23:26:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A01772145D for ; Thu, 19 Nov 2020 23:26:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="HMfweoFp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727095AbgKSX01 (ORCPT ); Thu, 19 Nov 2020 18:26:27 -0500 Received: from linux.microsoft.com ([13.77.154.182]:32978 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727069AbgKSX0Z (ORCPT ); Thu, 19 Nov 2020 18:26:25 -0500 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 0411720B7133; Thu, 19 Nov 2020 15:26:23 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 0411720B7133 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1605828384; bh=zxzJjRVL4Fw/rli7hkZOoZEuxfHZymVb0lvoIbeaev0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HMfweoFp7uHK00RJeXeETLV0MZGJdjAIqIz5bVWxDLV8uCide56pZiI4B2M1mhyCb mff2cJPlCShtEo1DjwLEns1rswSZVbfmIm/UM3jBCxU7y6s5EMObHcS8MYIXjiEddf qcNIKd2hrOxzFfwrhfYSEwT/87v5ugPIppyH/5iY= From: Tushar Sugandhi To: 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 Cc: tyhicks@linux.microsoft.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: [PATCH v6 6/8] IMA: add support to critical data hook to limit data sources for measurement Date: Thu, 19 Nov 2020 15:26:09 -0800 Message-Id: <20201119232611.30114-7-tusharsu@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201119232611.30114-1-tusharsu@linux.microsoft.com> References: <20201119232611.30114-1-tusharsu@linux.microsoft.com> Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org The IMA hook ima_measure_critical_data() does not support a way to specify the source of the critical data provider. Thus, the data measurement cannot be constrained, based on the data source, through the IMA policy. Extend the IMA hook ima_measure_critical_data() to support passing the data source name as an input parameter, so that the policy rule can be used to limit data sources being measured. Signed-off-by: Tushar Sugandhi --- include/linux/ima.h | 6 ++++-- security/integrity/ima/ima_main.c | 11 ++++++++--- 2 files changed, 12 insertions(+), 5 deletions(-) diff --git a/include/linux/ima.h b/include/linux/ima.h index 9911a6e496b6..60ba073f1575 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -30,7 +30,8 @@ extern int ima_post_read_file(struct file *file, void *buf, loff_t size, extern void ima_post_path_mknod(struct dentry *dentry); extern int ima_file_hash(struct file *file, char *buf, size_t buf_size); extern void ima_kexec_cmdline(int kernel_fd, const void *buf, int size); -extern void ima_measure_critical_data(const char *event_name, +extern void ima_measure_critical_data(const char *event_data_source, + const char *event_name, const void *buf, int buf_len, bool measure_buf_hash); @@ -119,7 +120,8 @@ static inline int ima_file_hash(struct file *file, char *buf, size_t buf_size) } static inline void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) {} -static inline void ima_measure_critical_data(const char *event_name, +static inline void ima_measure_critical_data(const char *event_data_source, + const char *event_name, const void *buf, int buf_len, bool measure_buf_hash) {} #endif /* CONFIG_IMA */ diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 7661f09569f3..27b8b8316622 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -924,6 +924,7 @@ void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) /** * ima_measure_critical_data - measure kernel integrity critical data + * @event_data_source: kernel data source being measured * @event_name: event name to be used for the buffer entry * @buf: pointer to buffer containing data to measure * @buf_len: length of buffer(in bytes) @@ -932,6 +933,9 @@ void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) * Measure the kernel subsystem data, critical to the integrity of the kernel, * into the IMA log and extend the @pcr. * + * Use @event_data_source to describe the kernel data source for the buffer + * being measured. + * * Use @event_name to describe the state/buffer data change. * Examples of critical data (buf) could be kernel in-memory r/o structures, * hash of the memory structures, or data that represents subsystem state @@ -944,17 +948,18 @@ void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) * * The data (buf) can only be measured, not appraised. */ -void ima_measure_critical_data(const char *event_name, +void ima_measure_critical_data(const char *event_data_source, + const char *event_name, const void *buf, int buf_len, bool measure_buf_hash) { - if (!event_name || !buf || !buf_len) { + if (!event_name || !event_data_source || !buf || !buf_len) { pr_err("Invalid arguments passed to %s().\n", __func__); return; } process_buffer_measurement(NULL, buf, buf_len, event_name, - CRITICAL_DATA, 0, NULL, + CRITICAL_DATA, 0, event_data_source, measure_buf_hash); } From patchwork Thu Nov 19 23:26:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tushar Sugandhi X-Patchwork-Id: 11919177 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=-23.4 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, UNWANTED_LANGUAGE_BODY,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 EDD23C83013 for ; Thu, 19 Nov 2020 23:26:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A89942145D for ; Thu, 19 Nov 2020 23:26:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="qEZd7tyF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727152AbgKSX0i (ORCPT ); Thu, 19 Nov 2020 18:26:38 -0500 Received: from linux.microsoft.com ([13.77.154.182]:33002 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727070AbgKSX00 (ORCPT ); Thu, 19 Nov 2020 18:26:26 -0500 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 94B1F20B8005; Thu, 19 Nov 2020 15:26:24 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 94B1F20B8005 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1605828385; bh=uk4x4LQiWntk6528VOlokJxBRGx63RfP1GrYurFa5OI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qEZd7tyFxy6Hzpyvftyyglq0YHDh6WKPkmyzcSyI4JZCdGKJ0J3/YPV6L2iMDYBWz 7DTsQuz9XNOb7JLLg74Q5ZVpqqnMCuhsgcNsvU4/oVtFX7OD4MYi250SWEXB7TuGJc QQ8BPP/Mb+wuewh7tm72NOYej0SpBDWctJcWzO2o= From: Tushar Sugandhi To: 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 Cc: tyhicks@linux.microsoft.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: [PATCH v6 7/8] IMA: add a built-in policy rule for critical data measurement Date: Thu, 19 Nov 2020 15:26:10 -0800 Message-Id: <20201119232611.30114-8-tusharsu@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201119232611.30114-1-tusharsu@linux.microsoft.com> References: <20201119232611.30114-1-tusharsu@linux.microsoft.com> Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Lakshmi Ramasubramanian The IMA hook to measure kernel critical data, namely ima_measure_critical_data(), could be called before a custom IMA policy is loaded. Define a new critical data builtin policy to allow measuring early kernel integrity critical data before a custom IMA policy is loaded. Add critical data to built-in IMA rules if the kernel command line contains "ima_policy=critical_data". Signed-off-by: Lakshmi Ramasubramanian --- security/integrity/ima/ima_policy.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index c9e52dab0638..119604a3efa0 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -206,6 +206,10 @@ static struct ima_rule_entry secure_boot_rules[] __ro_after_init = { .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED}, }; +static struct ima_rule_entry critical_data_rules[] __ro_after_init = { + {.action = MEASURE, .func = CRITICAL_DATA, .flags = IMA_FUNC}, +}; + /* An array of architecture specific rules */ static struct ima_rule_entry *arch_policy_entry __ro_after_init; @@ -228,6 +232,7 @@ __setup("ima_tcb", default_measure_policy_setup); static bool ima_use_appraise_tcb __initdata; static bool ima_use_secure_boot __initdata; +static bool ima_use_critical_data __ro_after_init; static bool ima_fail_unverifiable_sigs __ro_after_init; static int __init policy_setup(char *str) { @@ -242,6 +247,8 @@ static int __init policy_setup(char *str) ima_use_appraise_tcb = true; else if (strcmp(p, "secure_boot") == 0) ima_use_secure_boot = true; + else if (strcmp(p, "critical_data") == 0) + ima_use_critical_data = true; else if (strcmp(p, "fail_securely") == 0) ima_fail_unverifiable_sigs = true; else @@ -875,6 +882,11 @@ void __init ima_init_policy(void) ARRAY_SIZE(default_appraise_rules), IMA_DEFAULT_POLICY); + if (ima_use_critical_data) + add_rules(critical_data_rules, + ARRAY_SIZE(critical_data_rules), + IMA_DEFAULT_POLICY); + ima_update_policy_flag(); } From patchwork Thu Nov 19 23:26:11 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tushar Sugandhi X-Patchwork-Id: 11919179 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=-26.2 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_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 A76C5C83018 for ; Thu, 19 Nov 2020 23:26:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 702892222A for ; Thu, 19 Nov 2020 23:26:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="Eh0J0BWt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727087AbgKSX0i (ORCPT ); Thu, 19 Nov 2020 18:26:38 -0500 Received: from linux.microsoft.com ([13.77.154.182]:32948 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727071AbgKSX00 (ORCPT ); Thu, 19 Nov 2020 18:26:26 -0500 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 3F33020B8007; Thu, 19 Nov 2020 15:26:25 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 3F33020B8007 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1605828385; bh=HQPjCXbmCWoNxq+crvgSRCDuSmapzAI99vhPLiG291M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Eh0J0BWtS8OEKfZFU22fAm2WREPLsbvN+DQS8POGO9JYEe7Ex4W5fv2nHM2MzLkS9 BcuYCYBT1YUfiA3t9pMv/XxKdXtTw/mzCEKJe9Bn3IUBQzNR0eScu4IMR0IgWl/GEB lswP8P9NqOEhbT36Zg4BKLQtyq392BoObRivaExw= From: Tushar Sugandhi To: 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 Cc: tyhicks@linux.microsoft.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: [PATCH v6 8/8] selinux: measure state and hash of the policy using IMA Date: Thu, 19 Nov 2020 15:26:11 -0800 Message-Id: <20201119232611.30114-9-tusharsu@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201119232611.30114-1-tusharsu@linux.microsoft.com> References: <20201119232611.30114-1-tusharsu@linux.microsoft.com> Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Lakshmi Ramasubramanian IMA measures files and buffer data such as keys, command line arguments passed to the kernel on kexec system call, etc. While these measurements enable monitoring and validating the integrity of the system, it is not sufficient. In-memory data structures maintained by various kernel components store the current state and policies configured for the components. Updates to these data structures would have an impact on the functionalities. For example, the in-memory data structures maintained by SELinux store the configuration and policies for this security module and thereby determine the security functionalities provided by this module. Changes to these data at runtime would have an impact on the security guarantees provided by SELinux. Measuring such in-memory data structures through IMA subsystem provides a secure way for a remote attestation service to know the state of the system and also the runtime changes in the state of the system. SELinux configuration and policy are some of the critical data for this security module that need to be measured. This measurement can be used by an attestation service, for instance, to verify if the configurations and policies have been setup correctly and that they haven't been tampered at run-time. Measure SELinux configurations, policy capabilities settings, and the hash of the loaded policy by calling the IMA hook ima_measure_critical_data(). Since the size of the loaded policy can be large (several MB), measure the hash of the policy instead of the entire policy to avoid bloating the IMA log entry. Add "selinux" to the list of supported data sources maintained by IMA to enable measuring SELinux data. To enable SELinux data measurement, the following steps are required: 1, Add "ima_policy=critical_data" to the kernel command line arguments to enable measuring SELinux data at boot time. For example, BOOT_IMAGE=/boot/vmlinuz-5.10.0-rc1+ root=UUID=fd643309-a5d2-4ed3-b10d-3c579a5fab2f ro nomodeset security=selinux ima_policy=critical_data 2, Add the following rule to /etc/ima/ima-policy measure func=CRITICAL_DATA data_sources=selinux template=ima-buf Sample measurement of SELinux state and hash of the policy: 10 e32e...5ac3 ima-buf sha256:86e8...4594 selinux-state-1595389364:287899386 696e697469616c697a65643d313b656e61626c65643d313b656e666f7263696e673d303b636865636b72657170726f743d313b6e6574776f726b5f706565725f636f6e74726f6c733d313b6f70656e5f7065726d733d313b657874656e6465645f736f636b65745f636c6173733d313b616c776179735f636865636b5f6e6574776f726b3d303b6367726f75705f7365636c6162656c3d313b6e6e705f6e6f737569645f7472616e736974696f6e3d313b67656e66735f7365636c6162656c5f73796d6c696e6b733d303 10 9e81...0857 ima-buf sha256:4941...68fc selinux-policy-hash-1597335667:462051628 8d1d...1834 To verify the measurement check the following: Execute the following command to extract the measured data from the IMA log for SELinux configuration (selinux-state). grep "selinux-state" /sys/kernel/security/integrity/ima/ascii_runtime_measurements | tail -1 | cut -d' ' -f 6 | xxd -r -p The output should be the list of key-value pairs. For example, initialized=1;enabled=1;enforcing=0;checkreqprot=1;network_peer_controls=1;open_perms=1;extended_socket_class=1;always_check_network=0;cgroup_seclabel=1;nnp_nosuid_transition=1;genfs_seclabel_symlinks=0; To verify the measured data with the current SELinux state: => enabled should be set to 1 if /sys/fs/selinux folder exists, 0 otherwise For other entries, compare the integer value in the files => /sys/fs/selinux/enforce => /sys/fs/selinux/checkreqprot And, each of the policy capabilities files under => /sys/fs/selinux/policy_capabilities Note that the actual verification would be against an expected state and done on a system other than the measured system, typically requiring "initialized=1; enabled=1;enforcing=1;checkreqprot=0;" for a secure state and then whatever policy capabilities are actually set in the expected policy (which can be extracted from the policy itself via seinfo, for example). For selinux-policy-hash, the hash of SELinux policy is included in the IMA log entry. To verify the measured data with the current SELinux policy run the following commands and verify the output hash values match. sha256sum /sys/fs/selinux/policy | cut -d' ' -f 1 grep "selinux-policy-hash" /sys/kernel/security/integrity/ima/ascii_runtime_measurements | tail -1 | cut -d' ' -f 6 Note that the actual verification of SELinux policy would require loading the expected policy into an identical kernel on a pristine/known-safe system and run the sha256sum /sys/kernel/selinux/policy there to get the expected hash. Signed-off-by: Lakshmi Ramasubramanian Suggested-by: Stephen Smalley --- Documentation/ABI/testing/ima_policy | 6 +- security/selinux/Makefile | 2 + security/selinux/hooks.c | 3 + security/selinux/include/security.h | 11 +- security/selinux/measure.c | 157 +++++++++++++++++++++++++++ security/selinux/selinuxfs.c | 8 ++ security/selinux/ss/services.c | 71 ++++++++++-- 7 files changed, 247 insertions(+), 11 deletions(-) create mode 100644 security/selinux/measure.c diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index ee60442a41cd..db1ee7bcdba7 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -52,7 +52,7 @@ Description: template:= name of a defined IMA template type (eg, ima-ng). Only valid when action is "measure". pcr:= decimal value - data_sources:= list of kernel subsystems that contain + data_sources:= list of kernel subsystems (eg, SeLinux) that contain kernel in-memory data critical to the integrity of the kernel. Only valid when action is "measure" and func is CRITICAL_DATA. @@ -135,3 +135,7 @@ Description: keys added to .builtin_trusted_keys or .ima keyring: measure func=KEY_CHECK keyrings=.builtin_trusted_keys|.ima + + Example of measure rule using CRITICAL_DATA to measure critical data + + measure func=CRITICAL_DATA data_sources=selinux diff --git a/security/selinux/Makefile b/security/selinux/Makefile index 4d8e0e8adf0b..83d512116341 100644 --- a/security/selinux/Makefile +++ b/security/selinux/Makefile @@ -16,6 +16,8 @@ selinux-$(CONFIG_NETLABEL) += netlabel.o selinux-$(CONFIG_SECURITY_INFINIBAND) += ibpkey.o +selinux-$(CONFIG_IMA) += measure.o + ccflags-y := -I$(srctree)/security/selinux -I$(srctree)/security/selinux/include $(addprefix $(obj)/,$(selinux-y)): $(obj)/flask.h diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 6b1826fc3658..8b9fde47ae28 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -7398,6 +7398,9 @@ int selinux_disable(struct selinux_state *state) } selinux_mark_disabled(state); + mutex_lock(&state->policy_mutex); + selinux_measure_state(state); + mutex_unlock(&state->policy_mutex); pr_info("SELinux: Disabled at runtime.\n"); diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h index 3cc8bab31ea8..18ee65c98446 100644 --- a/security/selinux/include/security.h +++ b/security/selinux/include/security.h @@ -229,7 +229,8 @@ void selinux_policy_cancel(struct selinux_state *state, struct selinux_policy *policy); int security_read_policy(struct selinux_state *state, void **data, size_t *len); - +int security_read_policy_kernel(struct selinux_state *state, + void **data, size_t *len); int security_policycap_supported(struct selinux_state *state, unsigned int req_cap); @@ -446,4 +447,12 @@ extern void ebitmap_cache_init(void); extern void hashtab_cache_init(void); extern int security_sidtab_hash_stats(struct selinux_state *state, char *page); +#ifdef CONFIG_IMA +extern void selinux_measure_state(struct selinux_state *selinux_state); +#else +static inline void selinux_measure_state(struct selinux_state *selinux_state) +{ +} +#endif + #endif /* _SELINUX_SECURITY_H_ */ diff --git a/security/selinux/measure.c b/security/selinux/measure.c new file mode 100644 index 000000000000..65d42059f588 --- /dev/null +++ b/security/selinux/measure.c @@ -0,0 +1,157 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Measure SELinux state using IMA subsystem. + */ +#include +#include +#include +#include "security.h" + +/* + * This function creates a unique name by appending the timestamp to + * the given string. This string is passed as "event_name" to the IMA + * hook to measure the given SELinux data. + * + * The data provided by SELinux to the IMA subsystem for measuring may have + * already been measured (for instance the same state existed earlier). + * But for SELinux the current data represents a state change and hence + * needs to be measured again. To enable this, pass a unique "event_name" + * to the IMA hook so that IMA subsystem will always measure the given data. + * + * For example, + * At time T0 SELinux data to be measured is "foo". IMA measures it. + * At time T1 the data is changed to "bar". IMA measures it. + * At time T2 the data is changed to "foo" again. IMA will not measure it + * (since it was already measured) unless the event_name, for instance, + * is different in this call. + */ +static char *selinux_event_name(const char *name_prefix) +{ + char *event_name = NULL; + struct timespec64 cur_time; + + ktime_get_real_ts64(&cur_time); + event_name = kasprintf(GFP_KERNEL, "%s-%lld:%09ld", name_prefix, + cur_time.tv_sec, cur_time.tv_nsec); + if (!event_name) { + pr_err("%s: event name not allocated.\n", __func__); + return NULL; + } + + return event_name; +} + +static int read_selinux_state(char **state_str, int *state_str_len, + struct selinux_state *state) +{ + char *buf, *str_fmt = "%s=%d;"; + int i, buf_len, curr; + bool initialized = selinux_initialized(state); + bool enabled = !selinux_disabled(state); + bool enforcing = enforcing_enabled(state); + bool checkreqprot = checkreqprot_get(state); + + buf_len = snprintf(NULL, 0, str_fmt, "initialized", initialized); + buf_len += snprintf(NULL, 0, str_fmt, "enabled", enabled); + buf_len += snprintf(NULL, 0, str_fmt, "enforcing", enforcing); + buf_len += snprintf(NULL, 0, str_fmt, "checkreqprot", checkreqprot); + + for (i = 0; i < __POLICYDB_CAPABILITY_MAX; i++) { + buf_len += snprintf(NULL, 0, str_fmt, + selinux_policycap_names[i], + state->policycap[i]); + } + ++buf_len; + + buf = kzalloc(buf_len, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + curr = scnprintf(buf, buf_len, str_fmt, + "initialized", initialized); + curr += scnprintf((buf + curr), (buf_len - curr), str_fmt, + "enabled", enabled); + curr += scnprintf((buf + curr), (buf_len - curr), str_fmt, + "enforcing", enforcing); + curr += scnprintf((buf + curr), (buf_len - curr), str_fmt, + "checkreqprot", checkreqprot); + + for (i = 0; i < __POLICYDB_CAPABILITY_MAX; i++) { + curr += scnprintf((buf + curr), (buf_len - curr), str_fmt, + selinux_policycap_names[i], + state->policycap[i]); + } + + *state_str = buf; + *state_str_len = curr; + + return 0; +} + +/* + * selinux_measure_state - Measure SELinux state configuration and hash of + * the SELinux policy. + * @state: selinux state struct + * + * NOTE: This function must be called with policy_mutex held. + */ +void selinux_measure_state(struct selinux_state *state) +{ + void *policy = NULL; + char *state_event_name = NULL; + char *policy_event_name = NULL; + char *state_str = NULL; + size_t policy_len; + int state_str_len, rc = 0; + bool initialized = selinux_initialized(state); + + /* + * Get a unique string for measuring the current SELinux state. + */ + state_event_name = selinux_event_name("selinux-state"); + if (!state_event_name) { + pr_err("%s: Event name for state not allocated.\n", + __func__); + rc = -ENOMEM; + goto out; + } + + rc = read_selinux_state(&state_str, &state_str_len, state); + if (rc) { + pr_err("%s: Failed to read state %d.\n", __func__, rc); + goto out; + } + + ima_measure_critical_data("selinux", state_event_name, + state_str, state_str_len, false); + + /* + * Measure SELinux policy only after initialization is completed. + */ + if (!initialized) + goto out; + + policy_event_name = selinux_event_name("selinux-policy-hash"); + if (!policy_event_name) { + pr_err("%s: Event name for policy not allocated.\n", + __func__); + rc = -ENOMEM; + goto out; + } + + rc = security_read_policy_kernel(state, &policy, &policy_len); + if (rc) { + pr_err("%s: Failed to read policy %d.\n", __func__, rc); + goto out; + } + + ima_measure_critical_data("selinux", policy_event_name, + policy, policy_len, true); + + vfree(policy); + +out: + kfree(policy_event_name); + kfree(state_str); + kfree(state_event_name); +} diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index 4bde570d56a2..015650220cb2 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -182,6 +182,10 @@ static ssize_t sel_write_enforce(struct file *file, const char __user *buf, selinux_status_update_setenforce(state, new_value); if (!new_value) call_blocking_lsm_notifier(LSM_POLICY_CHANGE, NULL); + + mutex_lock(&state->policy_mutex); + selinux_measure_state(state); + mutex_unlock(&state->policy_mutex); } length = count; out: @@ -762,6 +766,10 @@ static ssize_t sel_write_checkreqprot(struct file *file, const char __user *buf, checkreqprot_set(fsi->state, (new_value ? 1 : 0)); length = count; + + mutex_lock(&fsi->state->policy_mutex); + selinux_measure_state(fsi->state); + mutex_unlock(&fsi->state->policy_mutex); out: kfree(page); return length; diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index 9704c8a32303..dfa2e00894ae 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -2180,6 +2180,7 @@ static void selinux_notify_policy_change(struct selinux_state *state, selinux_status_update_policyload(state, seqno); selinux_netlbl_cache_invalidate(); selinux_xfrm_notify_policyload(); + selinux_measure_state(state); } void selinux_policy_commit(struct selinux_state *state, @@ -3875,8 +3876,33 @@ int security_netlbl_sid_to_secattr(struct selinux_state *state, } #endif /* CONFIG_NETLABEL */ +/** + * security_read_selinux_policy - read the policy. + * @policy: SELinux policy + * @data: binary policy data + * @len: length of data in bytes + * + */ +static int security_read_selinux_policy(struct selinux_policy *policy, + void *data, size_t *len) +{ + int rc; + struct policy_file fp; + + fp.data = data; + fp.len = *len; + + rc = policydb_write(&policy->policydb, &fp); + if (rc) + return rc; + + *len = (unsigned long)fp.data - (unsigned long)data; + return 0; +} + /** * security_read_policy - read the policy. + * @state: selinux_state * @data: binary policy data * @len: length of data in bytes * @@ -3885,8 +3911,6 @@ int security_read_policy(struct selinux_state *state, void **data, size_t *len) { struct selinux_policy *policy; - int rc; - struct policy_file fp; policy = rcu_dereference_protected( state->policy, lockdep_is_held(&state->policy_mutex)); @@ -3898,14 +3922,43 @@ int security_read_policy(struct selinux_state *state, if (!*data) return -ENOMEM; - fp.data = *data; - fp.len = *len; + return security_read_selinux_policy(policy, *data, len); +} - rc = policydb_write(&policy->policydb, &fp); - if (rc) - return rc; +/** + * security_read_policy_kernel - read the policy. + * @state: selinux_state + * @data: binary policy data + * @len: length of data in bytes + * + * Allocates kernel memory for reading SELinux policy. + * This function is for internal use only and should not + * be used for returning data to user space. + * + * This function must be called with policy_mutex held. + */ +int security_read_policy_kernel(struct selinux_state *state, + void **data, size_t *len) +{ + struct selinux_policy *policy; + int rc = 0; - *len = (unsigned long)fp.data - (unsigned long)*data; - return 0; + policy = rcu_dereference_protected( + state->policy, lockdep_is_held(&state->policy_mutex)); + if (!policy) { + rc = -EINVAL; + goto out; + } + + *len = policy->policydb.len; + *data = vmalloc(*len); + if (!*data) { + rc = -ENOMEM; + goto out; + } + rc = security_read_selinux_policy(policy, *data, len); + +out: + return rc; }