From patchwork Wed Aug 5 00:43:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lakshmi Ramasubramanian X-Patchwork-Id: 11701087 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 54829722 for ; Wed, 5 Aug 2020 00:43:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4C67F20842 for ; Wed, 5 Aug 2020 00:43:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="SwPdfQBv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726724AbgHEAnj (ORCPT ); Tue, 4 Aug 2020 20:43:39 -0400 Received: from linux.microsoft.com ([13.77.154.182]:38366 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726197AbgHEAnh (ORCPT ); Tue, 4 Aug 2020 20:43:37 -0400 Received: from localhost.localdomain (c-73-42-176-67.hsd1.wa.comcast.net [73.42.176.67]) by linux.microsoft.com (Postfix) with ESMTPSA id ED0F120B490A; Tue, 4 Aug 2020 17:43:35 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com ED0F120B490A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1596588216; bh=SF9nLu7J2HUvWV7Tl+ZwVBSS+d5Qa91rslKFBRAWfq0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SwPdfQBvdVK2gPdIEwEvbF0H4ed7PrBGla5VF04p65M5fa0kMmJozKIJy+EBsm4ED IoSdqWDBoALJYHcJ6hvC2/wdNxRGXfVPt7hz8sGMGtppNduc8lPxSpMBISIjFkhIv2 XDlpO2YBoYk8MMgQ1tz4Fmm2OiglfUiHd95jSzLs= From: Lakshmi Ramasubramanian To: zohar@linux.ibm.com, stephen.smalley.work@gmail.com, casey@schaufler-ca.com Cc: tyhicks@linux.microsoft.com, sashal@kernel.org, jmorris@namei.org, linux-integrity@vger.kernel.org, selinux@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v6 1/4] IMA: Add func to measure LSM state and policy Date: Tue, 4 Aug 2020 17:43:28 -0700 Message-Id: <20200805004331.20652-2-nramas@linux.microsoft.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200805004331.20652-1-nramas@linux.microsoft.com> References: <20200805004331.20652-1-nramas@linux.microsoft.com> MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: Critical data structures of security modules need to be measured to enable an attestation service to verify if the configuration and policies for the security modules have been setup correctly and that they haven't been tampered with at runtime. A new IMA policy is required for handling this measurement. Define two new IMA policy func namely LSM_STATE and LSM_POLICY to measure the state and the policy provided by the security modules. Update ima_match_rules() and ima_validate_rule() to check for the new func and ima_parse_rule() to handle the new func. Signed-off-by: Lakshmi Ramasubramanian --- Documentation/ABI/testing/ima_policy | 9 ++++++++ security/integrity/ima/ima.h | 2 ++ security/integrity/ima/ima_api.c | 2 +- security/integrity/ima/ima_policy.c | 34 ++++++++++++++++++++++++---- 4 files changed, 42 insertions(+), 5 deletions(-) diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index cd572912c593..b7c7fb548c0c 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -30,6 +30,7 @@ Description: [FIRMWARE_CHECK] [KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK] [KEXEC_CMDLINE] [KEY_CHECK] + [LSM_STATE] [LSM_POLICY] mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND] [[^]MAY_EXEC] fsmagic:= hex value @@ -125,3 +126,11 @@ Description: keys added to .builtin_trusted_keys or .ima keyring: measure func=KEY_CHECK keyrings=.builtin_trusted_keys|.ima + + Example of measure rule using LSM_STATE to measure LSM state: + + measure func=LSM_STATE template=ima-buf + + Example of measure rule using LSM_POLICY to measure LSM policy: + + measure func=LSM_POLICY template=ima-ng diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 38043074ce5e..1b5f4b2f17d0 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -200,6 +200,8 @@ static inline unsigned int ima_hash_key(u8 *digest) hook(POLICY_CHECK, policy) \ hook(KEXEC_CMDLINE, kexec_cmdline) \ hook(KEY_CHECK, key) \ + hook(LSM_STATE, lsm_state) \ + hook(LSM_POLICY, lsm_policy) \ 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 4f39fb93f278..8c8b4e4a6493 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 | LSM_STATE | LSM_POLICY * 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 07f033634b27..e4de581442d5 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -442,13 +442,21 @@ 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_keyring(rule, keyring, 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_keyring(rule, keyring, cred)); + case LSM_STATE: + case LSM_POLICY: + return (rule->func == func); + default: + break; + } + if ((rule->flags & IMA_MASK) && (rule->mask != mask && func != POST_SETATTR)) return false; @@ -1044,6 +1052,18 @@ static bool ima_validate_rule(struct ima_rule_entry *entry) if (ima_rule_contains_lsm_cond(entry)) return false; + break; + case LSM_STATE: + case LSM_POLICY: + if (entry->action & ~(MEASURE | DONT_MEASURE)) + return false; + + if (entry->flags & ~(IMA_FUNC | IMA_PCR)) + return false; + + if (ima_rule_contains_lsm_cond(entry)) + return false; + break; default: return false; @@ -1176,6 +1196,12 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) entry->func = KEXEC_CMDLINE; else if (strcmp(args[0].from, "KEY_CHECK") == 0) entry->func = KEY_CHECK; + else if (IS_ENABLED(CONFIG_SECURITY_SELINUX) && + strcmp(args[0].from, "LSM_STATE") == 0) + entry->func = LSM_STATE; + else if (IS_ENABLED(CONFIG_SECURITY_SELINUX) && + strcmp(args[0].from, "LSM_POLICY") == 0) + entry->func = LSM_POLICY; else result = -EINVAL; if (!result)