From patchwork Fri Mar 3 18:18:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 13159224 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 5B933C7EE2F for ; Fri, 3 Mar 2023 18:22:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231684AbjCCSWe (ORCPT ); Fri, 3 Mar 2023 13:22:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42220 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231583AbjCCSWd (ORCPT ); Fri, 3 Mar 2023 13:22:33 -0500 Received: from frasgout12.his.huawei.com (frasgout12.his.huawei.com [14.137.139.154]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 489A41040E; Fri, 3 Mar 2023 10:22:15 -0800 (PST) Received: from mail02.huawei.com (unknown [172.18.147.229]) by frasgout12.his.huawei.com (SkyGuard) with ESMTP id 4PSx0d167rz9xtSG; Sat, 4 Mar 2023 02:13:05 +0800 (CST) Received: from huaweicloud.com (unknown [10.204.63.22]) by APP2 (Coremail) with SMTP id GxC2BwBnMVgKOgJk5iFpAQ--.12605S18; Fri, 03 Mar 2023 19:21:52 +0100 (CET) From: Roberto Sassu To: viro@zeniv.linux.org.uk, chuck.lever@oracle.com, jlayton@kernel.org, zohar@linux.ibm.com, dmitry.kasatkin@gmail.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, dhowells@redhat.com, jarkko@kernel.org, stephen.smalley.work@gmail.com, eparis@parisplace.org, casey@schaufler-ca.com, brauner@kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org, selinux@vger.kernel.org, linux-kernel@vger.kernel.org, stefanb@linux.ibm.com, Roberto Sassu Subject: [PATCH 16/28] security: Introduce file_post_open hook Date: Fri, 3 Mar 2023 19:18:30 +0100 Message-Id: <20230303181842.1087717-17-roberto.sassu@huaweicloud.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230303181842.1087717-1-roberto.sassu@huaweicloud.com> References: <20230303181842.1087717-1-roberto.sassu@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: GxC2BwBnMVgKOgJk5iFpAQ--.12605S18 X-Coremail-Antispam: 1UD129KBjvJXoWxJF1fWrW8KF1DZFWruFWkXrb_yoWrXr1kpF ZYy3WUGFW8GFy7Wrn7Aanrua4ag39agryUWrZ5u345tFn2qrnYgFZ0yF1Ykr15JrZYyFyx X3W2grW3Cr1DAFJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPqb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUAV Cq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0 rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4x0Y4vE2Ix0cI8IcVCY1x0267 AKxVWxJr0_GcWl84ACjcxK6I8E87Iv67AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv6xkF7I0E 14v26F4UJVW0owAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I 80ewAv7VC0I7IYx2IY67AKxVWUGVWUXwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCj c4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4IIrI8v6xkF7I0E8cxan2IY04v7MxkF7I0En4 kS14v26r4a6rW5MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E 5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVW8ZV WrXwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26F1j6w1UMIIF0xvE2Ix0cI8IcVCY 1x0267AKxVWxJr0_GcWlIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14 v26r4j6F4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Cr1j6rxdYxBIdaVFxhVjvjDU0xZFpf9x 07j7GYLUUUUU= X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAgAFBF1jj4YveQAAsi X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Roberto Sassu In preparation to move IMA and EVM to the LSM infrastructure, introduce the file_post_open hook. Also, export security_file_post_open() for NFS. Signed-off-by: Roberto Sassu Reviewed-by: Stefan Berger --- fs/namei.c | 2 ++ fs/nfsd/vfs.c | 6 ++++++ include/linux/lsm_hook_defs.h | 1 + include/linux/security.h | 6 ++++++ security/security.c | 17 +++++++++++++++++ 5 files changed, 32 insertions(+) diff --git a/fs/namei.c b/fs/namei.c index b4c52c4890b..41f7fdf4657 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3558,6 +3558,8 @@ static int do_open(struct nameidata *nd, error = may_open(idmap, &nd->path, acc_mode, open_flag); if (!error && !(file->f_mode & FMODE_OPENED)) error = vfs_open(&nd->path, file); + if (!error) + error = security_file_post_open(file, op->acc_mode); if (!error) error = ima_file_check(file, op->acc_mode); if (!error && do_truncate) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index e7462b5e5f1..4b86c158ffb 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -852,6 +852,12 @@ __nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, goto out_nfserr; } + host_err = security_file_post_open(file, may_flags); + if (host_err) { + fput(file); + goto out_nfserr; + } + host_err = ima_file_check(file, may_flags); if (host_err) { fput(file); diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 2ae5224d967..5d4e256e250 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -187,6 +187,7 @@ LSM_HOOK(int, 0, file_send_sigiotask, struct task_struct *tsk, struct fown_struct *fown, int sig) LSM_HOOK(int, 0, file_receive, struct file *file) LSM_HOOK(int, 0, file_open, struct file *file) +LSM_HOOK(int, 0, file_post_open, struct file *file, int mask) LSM_HOOK(int, 0, file_truncate, struct file *file) LSM_HOOK(int, 0, task_alloc, struct task_struct *task, unsigned long clone_flags) diff --git a/include/linux/security.h b/include/linux/security.h index b511f608958..4fdc62a1b42 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -402,6 +402,7 @@ int security_file_send_sigiotask(struct task_struct *tsk, struct fown_struct *fown, int sig); int security_file_receive(struct file *file); int security_file_open(struct file *file); +int security_file_post_open(struct file *file, int mask); int security_file_truncate(struct file *file); int security_task_alloc(struct task_struct *task, unsigned long clone_flags); void security_task_free(struct task_struct *task); @@ -1043,6 +1044,11 @@ static inline int security_file_open(struct file *file) return 0; } +static inline int security_file_post_open(struct file *file, int mask) +{ + return 0; +} + static inline int security_file_truncate(struct file *file) { return 0; diff --git a/security/security.c b/security/security.c index 6bf4a92db94..e252c87df4f 100644 --- a/security/security.c +++ b/security/security.c @@ -2906,6 +2906,23 @@ int security_file_open(struct file *file) return fsnotify_perm(file, MAY_OPEN); } +/** + * security_file_post_open() - Recheck access to a file after it has been opened + * @file: the file + * @mask: access mask + * + * Recheck access with mask after the file has been opened. The hook is useful + * for LSMs that require the file content to be available in order to make + * decisions. + * + * Return: Returns 0 if permission is granted. + */ +int security_file_post_open(struct file *file, int mask) +{ + return call_int_hook(file_post_open, 0, file, mask); +} +EXPORT_SYMBOL_GPL(security_file_post_open); + /** * security_file_truncate() - Check if truncating a file is allowed * @file: file