From patchwork Wed Dec 9 19:42:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tushar Sugandhi X-Patchwork-Id: 11962361 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 A163BC4361B for ; Wed, 9 Dec 2020 19:48:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6643023C8F for ; Wed, 9 Dec 2020 19:48:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387991AbgLITrE (ORCPT ); Wed, 9 Dec 2020 14:47:04 -0500 Received: from linux.microsoft.com ([13.77.154.182]:47492 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387857AbgLITnG (ORCPT ); Wed, 9 Dec 2020 14:43:06 -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 A6EB720B7189; Wed, 9 Dec 2020 11:42:24 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com A6EB720B7189 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1607542945; bh=13W9y/glUb8I3SzOqOuxO+1MJwZs/tFHH0a5DtYqn+g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TZVpGynKEEZSZfv4sGpjoXpRov6wDOKUZe6Bk2s0M7IyWfEjL11cvBW/RiftHz9k1 8vI8zRWmbI63YTH0/dTkHJXgwqs1bxLGX1+6La9EI/+jASChz6i/LT+0FX+9tNXTrX ACemq6NpMQLBt4kUsRNpMutGXMRsw7tTv2AaleWY= 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 v7 4/8] IMA: add policy rule to measure critical data Date: Wed, 9 Dec 2020 11:42:08 -0800 Message-Id: <20201209194212.5131-5-tusharsu@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201209194212.5131-1-tusharsu@linux.microsoft.com> References: <20201209194212.5131-1-tusharsu@linux.microsoft.com> Precedence: bulk List-ID: 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..9a8ee80a3128 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_SOURCE 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_source; /* Measure data from this source */ 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_source) + return true; + else + opt_list = rule->data_source; + 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_SOURCE) || + (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_PCR | + IMA_DATA_SOURCE))) + return false; + + if (ima_rule_contains_lsm_cond(entry)) + return false; + break; default: return false;