From patchwork Tue Dec 27 01:47:29 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guozihua (Scott)" X-Patchwork-Id: 13082012 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 95114C3DA79 for ; Tue, 27 Dec 2022 01:50:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232499AbiL0Buy (ORCPT ); Mon, 26 Dec 2022 20:50:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49182 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229578AbiL0Bus (ORCPT ); Mon, 26 Dec 2022 20:50:48 -0500 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 634F1315; Mon, 26 Dec 2022 17:50:47 -0800 (PST) Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4NgyJN5zYszJqhK; Tue, 27 Dec 2022 09:49:40 +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; Tue, 27 Dec 2022 09:50:45 +0800 From: GUO Zihua To: , , CC: , , Subject: [PATCH 2/2] ima: Handle -ESTALE returned by ima_filter_rule_match() Date: Tue, 27 Dec 2022 09:47:29 +0800 Message-ID: <20221227014729.4799-3-guozihua@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20221227014729.4799-1-guozihua@huawei.com> References: <20221227014729.4799-1-guozihua@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.175.31] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) 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 Cc: stable@vger.kernel.org # 4.19.y --- security/integrity/ima/ima_policy.c | 34 ++++++++++++++++++++++------- 1 file changed, 26 insertions(+), 8 deletions(-) diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 1e0251e9510a..dd146a34a53a 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -378,6 +378,9 @@ 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)) @@ -416,35 +419,50 @@ 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; + } } - return true; + result = true; + +out: + if (rule_reinitialized) + ima_lsm_free_rule(lsm_rule); + return result; } /*