From patchwork Tue Feb 15 12:40:38 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 12747017 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 5258BC433FE for ; Tue, 15 Feb 2022 12:42:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237812AbiBOMmI (ORCPT ); Tue, 15 Feb 2022 07:42:08 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:50176 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237771AbiBOMlw (ORCPT ); Tue, 15 Feb 2022 07:41:52 -0500 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0474C1400B; Tue, 15 Feb 2022 04:41:41 -0800 (PST) Received: from fraeml714-chm.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Jyggf2L8zz6803S; Tue, 15 Feb 2022 20:41:18 +0800 (CST) Received: from roberto-ThinkStation-P620.huawei.com (10.204.63.22) by fraeml714-chm.china.huawei.com (10.206.15.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Tue, 15 Feb 2022 13:41:39 +0100 From: Roberto Sassu To: , , , , , , CC: , , , , , , Roberto Sassu Subject: [PATCH v2 2/6] ima: Always return a file measurement in ima_file_hash() Date: Tue, 15 Feb 2022 13:40:38 +0100 Message-ID: <20220215124042.186506-3-roberto.sassu@huawei.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220215124042.186506-1-roberto.sassu@huawei.com> References: <20220215124042.186506-1-roberto.sassu@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.204.63.22] X-ClientProxiedBy: lhreml753-chm.china.huawei.com (10.201.108.203) To fraeml714-chm.china.huawei.com (10.206.15.33) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org __ima_inode_hash() checks if a digest has been already calculated by looking for the integrity_iint_cache structure associated to the passed inode. Users of ima_file_hash() (e.g. eBPF) might be interested in obtaining the information without having to setup an IMA policy so that the digest is always available at the time they call this function. Call ima_collect_measurement() in __ima_inode_hash(), if the file descriptor is available (passed by ima_file_hash()), and store the file measurement in a temporary integrity_iint_cache structure. This change does not cause memory usage increase, due to using the temporary integrity_iint_cache structure, and due to freeing the ima_digest_data structure inside integrity_iint_cache before exiting from __ima_inode_hash(). For compatibility reasons, the behavior of ima_inode_hash() remains unchanged. Signed-off-by: Roberto Sassu --- security/integrity/ima/ima_main.c | 36 +++++++++++++++++++++---------- 1 file changed, 25 insertions(+), 11 deletions(-) diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 946ba8a12eab..3562a212a5ba 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -520,15 +520,27 @@ int ima_file_check(struct file *file, int mask) } EXPORT_SYMBOL_GPL(ima_file_check); -static int __ima_inode_hash(struct inode *inode, char *buf, size_t buf_size) +static int __ima_inode_hash(struct inode *inode, struct file *file, char *buf, + size_t buf_size) { - struct integrity_iint_cache *iint; - int hash_algo; + struct integrity_iint_cache *iint = NULL, tmp_iint; + int rc, hash_algo; - if (!ima_policy_flag) - return -EOPNOTSUPP; + if (ima_policy_flag) + iint = integrity_iint_find(inode); + + if (!iint && file) { + memset(&tmp_iint, 0, sizeof(tmp_iint)); + tmp_iint.inode = inode; + + rc = ima_collect_measurement(&tmp_iint, file, NULL, 0, + ima_hash_algo, NULL); + if (rc < 0) + return -EOPNOTSUPP; + + iint = &tmp_iint; + } - iint = integrity_iint_find(inode); if (!iint) return -EOPNOTSUPP; @@ -552,12 +564,14 @@ static int __ima_inode_hash(struct inode *inode, char *buf, size_t buf_size) hash_algo = iint->ima_hash->algo; mutex_unlock(&iint->mutex); + if (iint == &tmp_iint) + kfree(iint->ima_hash); + return hash_algo; } /** - * ima_file_hash - return the stored measurement if a file has been hashed and - * is in the iint cache. + * ima_file_hash - return a measurement of the file * @file: pointer to the file * @buf: buffer in which to store the hash * @buf_size: length of the buffer @@ -570,7 +584,7 @@ static int __ima_inode_hash(struct inode *inode, char *buf, size_t buf_size) * The file hash returned is based on the entire file, including the appended * signature. * - * If IMA is disabled or if no measurement is available, return -EOPNOTSUPP. + * If the measurement cannot be performed, return -EOPNOTSUPP. * If the parameters are incorrect, return -EINVAL. */ int ima_file_hash(struct file *file, char *buf, size_t buf_size) @@ -578,7 +592,7 @@ int ima_file_hash(struct file *file, char *buf, size_t buf_size) if (!file) return -EINVAL; - return __ima_inode_hash(file_inode(file), buf, buf_size); + return __ima_inode_hash(file_inode(file), file, buf, buf_size); } EXPORT_SYMBOL_GPL(ima_file_hash); @@ -605,7 +619,7 @@ int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size) if (!inode) return -EINVAL; - return __ima_inode_hash(inode, buf, buf_size); + return __ima_inode_hash(inode, NULL, buf, buf_size); } EXPORT_SYMBOL_GPL(ima_inode_hash);