From patchwork Fri Aug 21 18:21:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tushar Sugandhi X-Patchwork-Id: 11730179 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 228F9739 for ; Fri, 21 Aug 2020 18:21:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 032EB20735 for ; Fri, 21 Aug 2020 18:21:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="IckUdZxe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725951AbgHUSV2 (ORCPT ); Fri, 21 Aug 2020 14:21:28 -0400 Received: from linux.microsoft.com ([13.77.154.182]:42934 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725767AbgHUSVU (ORCPT ); Fri, 21 Aug 2020 14:21:20 -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 4828C20B490A; Fri, 21 Aug 2020 11:21:17 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 4828C20B490A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1598034077; bh=kyLBeyHw68763pY/UIAlu+0vNqCE9GA4eKE1wEZjr24=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IckUdZxe27Dgc58njv9aINbL139X2xsJ02qO17ZgUgbld2MtPn4fQ81h1p6BhwpNi 3AN1AVA3cNvCFRtxvm+0jP9aJCrFOJXCvpP4tCkN0CFM5EA/AcsXZ2wv4z/eelLOIh uMZHN3dMfEQDIN8SPhqlbb4SQE0C3CTLWF2BWAKw= 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 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 v2 1/3] IMA: generalize keyring specific measurement constructs Date: Fri, 21 Aug 2020 11:21:05 -0700 Message-Id: <20200821182107.5328-2-tusharsu@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200821182107.5328-1-tusharsu@linux.microsoft.com> References: <20200821182107.5328-1-tusharsu@linux.microsoft.com> Sender: linux-integrity-owner@vger.kernel.org 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 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 | 42 ++++++++++++++++------------- 4 files changed, 33 insertions(+), 27 deletions(-) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 38043074ce5e..8875085db689 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -255,7 +255,7 @@ 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, @@ -267,7 +267,7 @@ 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, @@ -283,7 +283,7 @@ 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 8a91711ca79b..c870fd6d2f83 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -732,13 +732,13 @@ int ima_load_data(enum kernel_load_data_id id) * @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"; @@ -770,7 +770,7 @@ 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 fe1df373c113..8866e84d0062 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -451,15 +451,21 @@ 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 + * @opt_list: rule data to match func_data against + * @func_data: data to match against the measure rule data + * @allow_empty_opt_list: If true matches all func_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 struct ima_rule_opt_list *opt_list, + const char *func_data, + bool allow_empty_opt_list, + const struct cred *cred) { bool matched = false; size_t i; @@ -467,14 +473,14 @@ static bool ima_match_keyring(struct ima_rule_entry *rule, if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid)) return false; - if (!rule->keyrings) - return true; + if (!opt_list) + return allow_empty_opt_list; - if (!keyring) + if (!func_data) 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; } @@ -491,20 +497,21 @@ 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, rule->keyrings, func_data, + true, cred); } if ((rule->flags & IMA_FUNC) && (rule->func != func && func != POST_SETATTR)) @@ -608,8 +615,7 @@ 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. @@ -621,7 +627,7 @@ 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); @@ -636,7 +642,7 @@ 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 Fri Aug 21 18:21:06 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tushar Sugandhi X-Patchwork-Id: 11730183 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 6A20B618 for ; Fri, 21 Aug 2020 18:21:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 476BD20720 for ; Fri, 21 Aug 2020 18:21:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="p/yLyA76" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726336AbgHUSV3 (ORCPT ); Fri, 21 Aug 2020 14:21:29 -0400 Received: from linux.microsoft.com ([13.77.154.182]:42944 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725768AbgHUSVU (ORCPT ); Fri, 21 Aug 2020 14:21:20 -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 D32F320B490D; Fri, 21 Aug 2020 11:21:17 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com D32F320B490D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1598034078; bh=THPhQYSGWWf/vJGv6pJZ+GxABGPB54BhjDbIaZ0H7dA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=p/yLyA76ppQeOHsJapq09OdzH8ILc9JTbW6Z7lavfQeXPJk3kGlzGEtSnOnBo1eYz RuHlOMdsk5JZsM55J9CLwOfPhCzPa9Rnd1Su/8Ua033rL6pAWMS29WkJ5YFsp/ZGxD aFRoCeFv/Y/NtUUdsofk/gc0UopHJuV+z6i0vpns= 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 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 v2 2/3] IMA: add policy to support measuring critical data from kernel components Date: Fri, 21 Aug 2020 11:21:06 -0700 Message-Id: <20200821182107.5328-3-tusharsu@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200821182107.5328-1-tusharsu@linux.microsoft.com> References: <20200821182107.5328-1-tusharsu@linux.microsoft.com> Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org There would be several candidate kernel components suitable for IMA measurement. Not all of them would have support for IMA measurement. Also, system administrators may not want to measure data for all of them, even when they support IMA measurement. An IMA policy specific to various kernel components is needed to measure their respective critical data. Add a new IMA policy CRITICAL_DATA+data_sources to support measuring various critical kernel components. This policy would enable the system administrators to limit the measurement to the components, if the components support IMA measurement. Signed-off-by: Tushar Sugandhi --- Documentation/ABI/testing/ima_policy | 6 ++- security/integrity/ima/ima.h | 1 + security/integrity/ima/ima_api.c | 2 +- security/integrity/ima/ima_policy.c | 62 +++++++++++++++++++++++++--- 4 files changed, 63 insertions(+), 8 deletions(-) diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index cd572912c593..a0dd0f108555 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -29,7 +29,7 @@ Description: base: 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 @@ -125,3 +125,7 @@ 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|apparmor|dm-crypt diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 8875085db689..0f4209a92bfb 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -200,6 +200,7 @@ 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_policy.c b/security/integrity/ima/ima_policy.c index 8866e84d0062..7b649095ac7a 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -33,6 +33,7 @@ #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 */ @@ -84,6 +85,7 @@ 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; }; @@ -508,14 +510,23 @@ 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, rule->keyrings, func_data, - true, cred); - } if ((rule->flags & IMA_FUNC) && (rule->func != func && func != POST_SETATTR)) return false; + + switch (func) { + case KEY_CHECK: + return ((rule->func == func) && + ima_match_rule_data(rule, rule->keyrings, + func_data, true, cred)); + case CRITICAL_DATA: + return ((rule->func == func) && + ima_match_rule_data(rule, rule->data_sources, + func_data, false, cred)); + default: + break; + } + if ((rule->flags & IMA_MASK) && (rule->mask != mask && func != POST_SETATTR)) return false; @@ -911,7 +922,7 @@ 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 = { @@ -948,6 +959,7 @@ 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} }; @@ -1110,6 +1122,19 @@ 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; @@ -1242,6 +1267,8 @@ 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) @@ -1312,6 +1339,23 @@ 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); @@ -1692,6 +1736,12 @@ 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 Fri Aug 21 18:21:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tushar Sugandhi X-Patchwork-Id: 11730193 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 98245739 for ; Fri, 21 Aug 2020 18:21:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7A92620720 for ; Fri, 21 Aug 2020 18:21:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="EMHAgV5I" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726599AbgHUSVo (ORCPT ); Fri, 21 Aug 2020 14:21:44 -0400 Received: from linux.microsoft.com ([13.77.154.182]:42958 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725831AbgHUSVV (ORCPT ); Fri, 21 Aug 2020 14:21:21 -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 7A7D020B490F; Fri, 21 Aug 2020 11:21:18 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 7A7D020B490F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1598034079; bh=uWkHzR0ZcqR9l/na6Wym14QYTHMQuhcrOfLOMA/iGiQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EMHAgV5IDY/3C0x3ia5Y0d2ylArOVJMHBaUlGWXWEhro5sJboXYUje3LtFyw00XjO dbHk02UU4JnJMtjcCe34K9mMC9SiwDjR+a3lU38Topi7SEQAq0cpTeAG/UQ5sJepsM INKitX4QfjSO3IF/t4+VvsC46+8eABshRtl9YYdw= 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 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 v2 3/3] IMA: define IMA hook to measure critical data from kernel components Date: Fri, 21 Aug 2020 11:21:07 -0700 Message-Id: <20200821182107.5328-4-tusharsu@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200821182107.5328-1-tusharsu@linux.microsoft.com> References: <20200821182107.5328-1-tusharsu@linux.microsoft.com> Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Currently, IMA does not provide a generic function to kernel components to measure their data. A generic function provided by IMA would enable various parts of the kernel with easier and faster on-boarding to use IMA infrastructure, would avoid code duplication, and consistent usage of IMA policy CRITICAL_DATA+data_sources across the kernel. Define a generic IMA function ima_measure_critical_data() to measure data from various kernel components. Limit the measurement to the components that are specified in the IMA policy - CRITICAL_DATA+data_sources. Update process_buffer_measurement() to return the status code of the operation. Introduce a boolean parameter measure_buf_hash to support measuring hash of a buffer, instead of the buffer itself. This is useful when the buffer being measured is too large, which may result in bloated IMA logs. Signed-off-by: Tushar Sugandhi --- include/linux/ima.h | 11 ++++ security/integrity/ima/ima.h | 7 ++- security/integrity/ima/ima_appraise.c | 2 +- security/integrity/ima/ima_asymmetric_keys.c | 2 +- security/integrity/ima/ima_main.c | 65 +++++++++++++++++--- security/integrity/ima/ima_queue_keys.c | 3 +- 6 files changed, 75 insertions(+), 15 deletions(-) diff --git a/include/linux/ima.h b/include/linux/ima.h index d15100de6cdd..136fc02580db 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -26,6 +26,10 @@ 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 int ima_measure_critical_data(const char *event_name, + const char *event_data_source, + const void *buf, int buf_len, + bool measure_buf_hash); #ifdef CONFIG_IMA_KEXEC extern void ima_add_kexec_buffer(struct kimage *image); @@ -104,6 +108,13 @@ 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 int ima_measure_critical_data(const char *event_name, + const char *event_data_source, + const void *buf, int buf_len, + bool measure_buf_hash) +{ + return -EOPNOTSUPP; +} #endif /* CONFIG_IMA */ #ifndef CONFIG_IMA_KEXEC diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 0f4209a92bfb..00b84052c8f1 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -266,9 +266,10 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file, struct evm_ima_xattr_data *xattr_value, int xattr_len, const struct modsig *modsig, int pcr, 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 process_buffer_measurement(struct inode *inode, const void *buf, int size, + const char *eventname, enum ima_hooks func, + 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 372d16382960..20adffe5bf58 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -336,7 +336,7 @@ 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 c870fd6d2f83..a889bf40cb7e 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -733,17 +733,21 @@ int ima_load_data(enum kernel_load_data_id id) * @func: IMA hook * @pcr: pcr to extend the measurement * @func_data: private data specific to @func, can be NULL. + * @measure_buf_hash: if set to true - will measure hash of the buf, + * instead of buf * * 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 *func_data) +int process_buffer_measurement(struct inode *inode, const void *buf, int size, + const char *eventname, enum ima_hooks func, + int pcr, const char *func_data, + bool measure_buf_hash) { int ret = 0; const char *audit_cause = "ENOMEM"; struct ima_template_entry *entry = NULL; struct integrity_iint_cache iint = {}; + struct integrity_iint_cache digest_iint = {}; struct ima_event_data event_data = {.iint = &iint, .filename = eventname, .buf = buf, @@ -752,13 +756,13 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size, struct { struct ima_digest_data hdr; char digest[IMA_MAX_DIGEST_SIZE]; - } hash = {}; + } hash = {}, digest_hash = {}; int violation = 0; int action = 0; u32 secid; if (!ima_policy_flag) - return; + return 0; /* * Both LSM hooks and auxilary based buffer measurements are @@ -772,7 +776,7 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size, action = ima_get_action(inode, current_cred(), secid, 0, func, &pcr, &template, func_data); if (!(action & IMA_MEASURE)) - return; + return 0; } if (!pcr) @@ -787,7 +791,7 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size, pr_err("template %s init failed, result: %d\n", (strlen(template->name) ? template->name : template->fmt), ret); - return; + return ret; } } @@ -801,6 +805,24 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size, goto out; } + if (measure_buf_hash) { + digest_iint.ima_hash = &digest_hash.hdr; + digest_iint.ima_hash->algo = ima_hash_algo; + digest_iint.ima_hash->length = hash_digest_size[ima_hash_algo]; + + ret = ima_calc_buffer_hash(hash.hdr.digest, + iint.ima_hash->length, + digest_iint.ima_hash); + if (ret < 0) { + audit_cause = "digest_hashing_error"; + goto out; + } + + event_data.iint = &digest_iint; + event_data.buf = hash.hdr.digest; + event_data.buf_len = iint.ima_hash->length; + } + ret = ima_alloc_init_template(&event_data, &entry, template); if (ret < 0) { audit_cause = "alloc_entry"; @@ -819,7 +841,7 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size, func_measure_str(func), audit_cause, ret, 0, ret); - return; + return ret; } /** @@ -842,10 +864,35 @@ 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); } +/** + * ima_measure_critical_data - measure critical data + * @event_name: name for the given data + * @event_data_source: name of the event data source + * @buf: pointer to buffer containing data to measure + * @buf_len: length of buffer(in bytes) + * @measure_buf_hash: if set to true - will measure hash of the buf, + * instead of buf + * + * Buffers can only be measured, not appraised. + */ +int ima_measure_critical_data(const char *event_name, + const char *event_data_source, + const void *buf, int buf_len, + bool measure_buf_hash) +{ + if (!event_name || !event_data_source || !buf || !buf_len) + return -EINVAL; + + return process_buffer_measurement(NULL, buf, buf_len, event_name, + CRITICAL_DATA, 0, event_data_source, + measure_buf_hash); +} + static int __init init_ima(void) { int error; 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); }