From patchwork Fri Sep 9 01:15:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guozihua (Scott)" X-Patchwork-Id: 12970891 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 C09D1ECAAD5 for ; Fri, 9 Sep 2022 01:19:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229495AbiIIBTF (ORCPT ); Thu, 8 Sep 2022 21:19:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229819AbiIIBTE (ORCPT ); Thu, 8 Sep 2022 21:19:04 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 551D5109D15; Thu, 8 Sep 2022 18:19:02 -0700 (PDT) Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.53]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4MNyl370HfzHnVm; Fri, 9 Sep 2022 09:17:03 +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 15.1.2375.24; Fri, 9 Sep 2022 09:19:00 +0800 From: GUO Zihua To: , , , , CC: , Subject: [PATCH v4 2/2] ima: Handle -ESTALE returned by ima_filter_rule_match() Date: Fri, 9 Sep 2022 09:15:16 +0800 Message-ID: <20220909011516.55957-3-guozihua@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220909011516.55957-1-guozihua@huawei.com> References: <20220909011516.55957-1-guozihua@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.175.31] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) 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 --- security/integrity/ima/ima_policy.c | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-) diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 8040215c0252..cb672df9b888 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -545,6 +545,8 @@ static bool ima_match_rules(struct ima_rule_entry *rule, const char *func_data) { int i; + bool result = false; + bool rule_reinitialized = false; if ((rule->flags & IMA_FUNC) && (rule->func != func && func != POST_SETATTR)) @@ -612,6 +614,8 @@ static bool ima_match_rules(struct ima_rule_entry *rule, else return false; } + +retry: switch (i) { case LSM_OBJ_USER: case LSM_OBJ_ROLE: @@ -631,10 +635,28 @@ static bool ima_match_rules(struct ima_rule_entry *rule, default: break; } - if (!rc) - return false; + + if (rc == -ESTALE) { + rule = ima_lsm_copy_rule(rule); + if (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(rule->lsm[i].rule); + kfree(rule); + } + return result; } /*