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 DD233C433FE for ; Thu, 16 Dec 2021 13:51:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236895AbhLPNvN (ORCPT ); Thu, 16 Dec 2021 08:51:13 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:42544 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229453AbhLPNvM (ORCPT ); Thu, 16 Dec 2021 08:51:12 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id DDE58B8245E; Thu, 16 Dec 2021 13:51:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 71F56C36AE0; Thu, 16 Dec 2021 13:51:03 +0000 (UTC) Date: Thu, 16 Dec 2021 14:51:00 +0100 From: Christian Brauner To: Stefan Berger Cc: linux-integrity@vger.kernel.org, zohar@linux.ibm.com, serge@hallyn.com, containers@lists.linux.dev, dmitry.kasatkin@gmail.com, ebiederm@xmission.com, krzysztof.struczynski@huawei.com, roberto.sassu@huawei.com, mpeters@redhat.com, lhinds@redhat.com, lsturman@redhat.com, puiterwi@redhat.com, jejb@linux.ibm.com, jamjoom@us.ibm.com, linux-kernel@vger.kernel.org, paul@paul-moore.com, rgb@redhat.com, linux-security-module@vger.kernel.org, jmorris@namei.org, Stefan Berger , James Bottomley Subject: Re: [PATCH v7 14/14] ima: Setup securityfs for IMA namespace Message-ID: <20211216135100.43suxkutyuwac7yh@wittgenstein> References: <20211216054323.1707384-1-stefanb@linux.vnet.ibm.com> <20211216054323.1707384-15-stefanb@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20211216054323.1707384-15-stefanb@linux.vnet.ibm.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 16, 2021 at 12:43:23AM -0500, Stefan Berger wrote: > From: Stefan Berger > > Setup securityfs with symlinks, directories, and files for IMA > namespacing support. The same directory structure that IMA uses on the > host is also created for the namespacing case. > > The securityfs file and directory ownerships cannot be set when the > IMA namespace is initialized. Therefore, delay the setup of the file > system to a later point when securityfs is in securityfs_fill_super. > > This filesystem can now be mounted as follows: > > mount -t securityfs /sys/kernel/security/ /sys/kernel/security/ > > The following directories, symlinks, and files are then available. > > $ ls -l sys/kernel/security/ > total 0 > lr--r--r--. 1 root root 0 Dec 2 00:18 ima -> integrity/ima > drwxr-xr-x. 3 root root 0 Dec 2 00:18 integrity > > $ ls -l sys/kernel/security/ima/ > total 0 > -r--r-----. 1 root root 0 Dec 2 00:18 ascii_runtime_measurements > -r--r-----. 1 root root 0 Dec 2 00:18 binary_runtime_measurements > -rw-------. 1 root root 0 Dec 2 00:18 policy > -r--r-----. 1 root root 0 Dec 2 00:18 runtime_measurements_count > -r--r-----. 1 root root 0 Dec 2 00:18 violations > > Signed-off-by: Stefan Berger > Signed-off-by: James Bottomley > --- > include/linux/ima.h | 14 ++++++++++++ > security/inode.c | 6 ++++- > security/integrity/ima/ima.h | 1 + > security/integrity/ima/ima_fs.c | 40 ++++++++++++++++++++++++--------- > 4 files changed, 49 insertions(+), 12 deletions(-) > > diff --git a/include/linux/ima.h b/include/linux/ima.h > index f9e592bb9560..a2705aa5242a 100644 > --- a/include/linux/ima.h > +++ b/include/linux/ima.h > @@ -40,6 +40,7 @@ extern int ima_measure_critical_data(const char *event_label, > const char *event_name, > const void *buf, size_t buf_len, > bool hash, u8 *digest, size_t digest_len); > +extern int ima_fs_ns_init(struct user_namespace *user_ns, struct dentry *root); > > #ifdef CONFIG_IMA_APPRAISE_BOOTPARAM > extern void ima_appraise_parse_cmdline(void); > @@ -232,6 +233,12 @@ static inline struct ima_namespace *get_current_ns(void) > return current_user_ns()->ima_ns; > } > > +static inline int ima_securityfs_init(struct user_namespace *user_ns, > + struct dentry *root) > +{ > + return ima_fs_ns_init(user_ns, root); > +} > + > #else > > static inline void free_ima_ns(struct user_namespace *user_ns) > @@ -250,6 +257,13 @@ static inline struct ima_namespace *get_current_ns(void) > { > return &init_ima_ns; > } > + > +static inline int ima_securityfs_init(struct user_namespace *ns, > + struct dentry *root) > +{ > + return 0; > +} > + > #endif /* CONFIG_IMA_NS */ > > #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING) > diff --git a/security/inode.c b/security/inode.c > index a0d9f086e3d5..ad9395d121f2 100644 > --- a/security/inode.c > +++ b/security/inode.c > @@ -16,6 +16,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -77,7 +78,10 @@ static int securityfs_fill_super(struct super_block *sb, struct fs_context *fc) > sb->s_op = &securityfs_super_operations; > sb->s_root->d_inode->i_op = &securityfs_dir_inode_operations; > > - return 0; > + if (ns != &init_user_ns) > + error = ima_securityfs_init(ns, sb->s_root); > + > + return error; > } > > static int securityfs_get_tree(struct fs_context *fc) > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h > index d51703290e25..9b0f6a3763f9 100644 > --- a/security/integrity/ima/ima.h > +++ b/security/integrity/ima/ima.h > @@ -148,6 +148,7 @@ struct ima_namespace { > int valid_policy; > > struct dentry *policy_dentry; > + bool policy_dentry_removed; > } __randomize_layout; > > extern const int read_idmap[]; > diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c > index 7c5a721f4f3d..3b8001ba62e3 100644 > --- a/security/integrity/ima/ima_fs.c > +++ b/security/integrity/ima/ima_fs.c > @@ -431,6 +431,7 @@ static int ima_release_policy(struct inode *inode, struct file *file) > #if !defined(CONFIG_IMA_WRITE_POLICY) && !defined(CONFIG_IMA_READ_POLICY) > securityfs_remove(ns->policy_dentry); > ns->policy_dentry = NULL; > + ns->policy_dentry_removed = true; > #elif defined(CONFIG_IMA_WRITE_POLICY) > clear_bit(IMA_FS_BUSY, &ns->ima_fs_flags); > #elif defined(CONFIG_IMA_READ_POLICY) > @@ -447,21 +448,31 @@ static const struct file_operations ima_measure_policy_ops = { > .llseek = generic_file_llseek, > }; > > -static int __init ima_fs_ns_init(struct user_namespace *user_ns) > +int ima_fs_ns_init(struct user_namespace *user_ns, struct dentry *root) > { > struct ima_namespace *ns = user_ns->ima_ns; > - struct dentry *ima_dir; > + struct dentry *int_dir; > + struct dentry *ima_dir = NULL; > struct dentry *ima_symlink = NULL; > struct dentry *binary_runtime_measurements = NULL; > struct dentry *ascii_runtime_measurements = NULL; > struct dentry *runtime_measurements_count = NULL; > struct dentry *violations = NULL; > > - ima_dir = securityfs_create_dir("ima", integrity_dir); > + /* FIXME: update when evm and integrity are namespaced */ > + if (user_ns != &init_user_ns) { > + int_dir = > + securityfs_create_dir("integrity", root); > + if (IS_ERR(int_dir)) > + return -1; That should probably be return PTR_ERR(int_dir)