From patchwork Thu Jan 5 06:23:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guozihua (Scott)" X-Patchwork-Id: 13089475 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BCEE4C54EBE for ; Thu, 5 Jan 2023 06:26:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230267AbjAEG0Y (ORCPT ); Thu, 5 Jan 2023 01:26:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50446 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230106AbjAEG0A (ORCPT ); Thu, 5 Jan 2023 01:26:00 -0500 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F2B662E3; Wed, 4 Jan 2023 22:25:59 -0800 (PST) Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.57]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4NnbwN6fDkzJq2l; Thu, 5 Jan 2023 14:21:56 +0800 (CST) Received: from huawei.com (10.67.175.31) by dggpemm500024.china.huawei.com (7.185.36.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.34; Thu, 5 Jan 2023 14:25:57 +0800 From: GUO Zihua To: , , CC: , , Subject: [PATCH v6 3/3] ima: Handle -ESTALE returned by ima_filter_rule_match() Date: Thu, 5 Jan 2023 14:23:12 +0800 Message-ID: <20230105062312.14325-4-guozihua@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20230105062312.14325-1-guozihua@huawei.com> References: <20230105062312.14325-1-guozihua@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.175.31] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpemm500024.china.huawei.com (7.185.36.203) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org [ Upstream commit c7423dbdbc9ecef7fff5239d144cad4b9887f4de ] IMA relies on the blocking LSM policy notifier callback to update the LSM based IMA policy rules. When SELinux update its policies, IMA would be notified and starts updating all its lsm rules one-by-one. During this time, -ESTALE would be returned by ima_filter_rule_match() if it is called with a LSM rule that has not yet been updated. In ima_match_rules(), -ESTALE is not handled, and the LSM rule is considered a match, causing extra files to be measured by IMA. Fix it by re-initializing a temporary rule if -ESTALE is returned by ima_filter_rule_match(). The origin rule in the rule list would be updated by the LSM policy notifier callback. Fixes: b16942455193 ("ima: use the lsm policy update notifier") Signed-off-by: GUO Zihua Reviewed-by: Roberto Sassu Signed-off-by: Mimi Zohar Signed-off-by: GUO Zihua --- security/integrity/ima/ima_policy.c | 37 ++++++++++++++++++++++------- 1 file changed, 29 insertions(+), 8 deletions(-) diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index d620c0dfc4e1..fb4ef8179e3e 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -375,6 +375,9 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode, enum ima_hooks func, int mask) { int i; + bool result = false; + struct ima_rule_entry *lsm_rule = rule; + bool rule_reinitialized = false; if ((rule->flags & IMA_FUNC) && (rule->func != func && func != POST_SETATTR)) @@ -413,35 +416,53 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode, int rc = 0; u32 osid; - if (!rule->lsm[i].rule) + if (!lsm_rule->lsm[i].rule) continue; +retry: switch (i) { case LSM_OBJ_USER: case LSM_OBJ_ROLE: case LSM_OBJ_TYPE: security_inode_getsecid(inode, &osid); rc = security_filter_rule_match(osid, - rule->lsm[i].type, + lsm_rule->lsm[i].type, Audit_equal, - rule->lsm[i].rule, + lsm_rule->lsm[i].rule, NULL); break; case LSM_SUBJ_USER: case LSM_SUBJ_ROLE: case LSM_SUBJ_TYPE: rc = security_filter_rule_match(secid, - rule->lsm[i].type, + lsm_rule->lsm[i].type, Audit_equal, - rule->lsm[i].rule, + lsm_rule->lsm[i].rule, NULL); default: break; } - if (!rc) - return false; + + if (rc == -ESTALE && !rule_reinitialized) { + lsm_rule = ima_lsm_copy_rule(rule); + if (lsm_rule) { + rule_reinitialized = true; + goto retry; + } + } + if (!rc) { + result = false; + goto out; + } + } + result = true; + +out: + if (rule_reinitialized) { + ima_lsm_free_rule(lsm_rule); + kfree(lsm_rule); } - return true; + return result; } /*