From patchwork Wed Sep 21 12:58:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guozihua (Scott)" X-Patchwork-Id: 12983709 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 ED2C6C32771 for ; Wed, 21 Sep 2022 13:01:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229938AbiIUNB5 (ORCPT ); Wed, 21 Sep 2022 09:01:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229908AbiIUNBx (ORCPT ); Wed, 21 Sep 2022 09:01:53 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0655E8E98A; Wed, 21 Sep 2022 06:01:51 -0700 (PDT) Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4MXdlS37TqzpV2q; Wed, 21 Sep 2022 20:59:00 +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 15.1.2375.31; Wed, 21 Sep 2022 21:01:49 +0800 From: GUO Zihua To: , , , , CC: , Subject: [PATCH v5 2/2] ima: Handle -ESTALE returned by ima_filter_rule_match() Date: Wed, 21 Sep 2022 20:58:04 +0800 Message-ID: <20220921125804.59490-3-guozihua@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220921125804.59490-1-guozihua@huawei.com> References: <20220921125804.59490-1-guozihua@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.175.31] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpemm500024.china.huawei.com (7.185.36.203) X-CFilter-Loop: Reflected Precedence: bulk List-ID: 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 --- security/integrity/ima/ima_policy.c | 41 ++++++++++++++++++++++------- 1 file changed, 32 insertions(+), 9 deletions(-) diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 8040215c0252..2edff7f58c25 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -545,6 +545,9 @@ static bool ima_match_rules(struct ima_rule_entry *rule, const char *func_data) { 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)) @@ -606,35 +609,55 @@ static bool ima_match_rules(struct ima_rule_entry *rule, int rc = 0; u32 osid; - if (!rule->lsm[i].rule) { - if (!rule->lsm[i].args_p) + if (!lsm_rule->lsm[i].rule) { + if (!lsm_rule->lsm[i].args_p) continue; else return false; } + +retry: switch (i) { case LSM_OBJ_USER: case LSM_OBJ_ROLE: case LSM_OBJ_TYPE: security_inode_getsecid(inode, &osid); - rc = ima_filter_rule_match(osid, rule->lsm[i].type, + rc = ima_filter_rule_match(osid, lsm_rule->lsm[i].type, Audit_equal, - rule->lsm[i].rule); + lsm_rule->lsm[i].rule); break; case LSM_SUBJ_USER: case LSM_SUBJ_ROLE: case LSM_SUBJ_TYPE: - rc = ima_filter_rule_match(secid, rule->lsm[i].type, + rc = ima_filter_rule_match(secid, lsm_rule->lsm[i].type, Audit_equal, - rule->lsm[i].rule); + lsm_rule->lsm[i].rule); break; 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) { + for (i = 0; i < MAX_LSM_RULES; i++) + ima_filter_rule_free(lsm_rule->lsm[i].rule); + kfree(lsm_rule); + } + return result; } /*