linux-kernel - [PATCH v7 13/14] ima: Move dentry into ima

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Message-Id: <20211216054323.1707384-14-stefanb@linux.vnet.ibm.com>
Date:   Thu, 16 Dec 2021 00:43:22 -0500
From:   Stefan Berger <stefanb@...ux.vnet.ibm.com>
To:     linux-integrity@...r.kernel.org
Cc:     zohar@...ux.ibm.com, serge@...lyn.com,
        christian.brauner@...ntu.com, containers@...ts.linux.dev,
        dmitry.kasatkin@...il.com, ebiederm@...ssion.com,
        krzysztof.struczynski@...wei.com, roberto.sassu@...wei.com,
        mpeters@...hat.com, lhinds@...hat.com, lsturman@...hat.com,
        puiterwi@...hat.com, jejb@...ux.ibm.com, jamjoom@...ibm.com,
        linux-kernel@...r.kernel.org, paul@...l-moore.com, rgb@...hat.com,
        linux-security-module@...r.kernel.org, jmorris@...ei.org,
        Stefan Berger <stefanb@...ux.ibm.com>
Subject: [PATCH v7 13/14] ima: Move dentry into ima_namespace and others onto stack

From: Stefan Berger <stefanb@...ux.ibm.com>

Move the policy file dentry into the ima_namespace for reuse by
virtualized SecurityFS and for being able to remove it from
the filesystem. Move the other dentries onto the stack.

Signed-off-by: Stefan Berger <stefanb@...ux.ibm.com>
---
 security/integrity/ima/ima.h    |  2 ++
 security/integrity/ima/ima_fs.c | 33 +++++++++++++++++++--------------
 2 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index cb6c92a67ff9..d51703290e25 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -146,6 +146,8 @@ struct ima_namespace {
 	struct mutex ima_write_mutex;
 	unsigned long ima_fs_flags;
 	int valid_policy;
+
+	struct dentry *policy_dentry;
 } __randomize_layout;
 
 extern const int read_idmap[];
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 611c4271d474..7c5a721f4f3d 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -359,14 +359,6 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
 	return result;
 }
 
-static struct dentry *ima_dir;
-static struct dentry *ima_symlink;
-static struct dentry *binary_runtime_measurements;
-static struct dentry *ascii_runtime_measurements;
-static struct dentry *runtime_measurements_count;
-static struct dentry *violations;
-static struct dentry *ima_policy;
-
 enum ima_fs_flags {
 	IMA_FS_BUSY,
 };
@@ -437,8 +429,8 @@ static int ima_release_policy(struct inode *inode, struct file *file)
 
 	ima_update_policy(ns);
 #if !defined(CONFIG_IMA_WRITE_POLICY) && !defined(CONFIG_IMA_READ_POLICY)
-	securityfs_remove(ima_policy);
-	ima_policy = NULL;
+	securityfs_remove(ns->policy_dentry);
+	ns->policy_dentry = NULL;
 #elif defined(CONFIG_IMA_WRITE_POLICY)
 	clear_bit(IMA_FS_BUSY, &ns->ima_fs_flags);
 #elif defined(CONFIG_IMA_READ_POLICY)
@@ -455,8 +447,16 @@ static const struct file_operations ima_measure_policy_ops = {
 	.llseek = generic_file_llseek,
 };
 
-int __init ima_fs_init(void)
+static int __init ima_fs_ns_init(struct user_namespace *user_ns)
 {
+	struct ima_namespace *ns = user_ns->ima_ns;
+	struct dentry *ima_dir;
+	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);
 	if (IS_ERR(ima_dir))
 		return -1;
@@ -493,20 +493,25 @@ int __init ima_fs_init(void)
 	if (IS_ERR(violations))
 		goto out;
 
-	ima_policy = securityfs_create_file("policy", POLICY_FILE_FLAGS,
+	ns->policy_dentry = securityfs_create_file("policy", POLICY_FILE_FLAGS,
 					    ima_dir, NULL,
 					    &ima_measure_policy_ops);
-	if (IS_ERR(ima_policy))
+	if (IS_ERR(ns->policy_dentry))
 		goto out;
 
 	return 0;
 out:
+	securityfs_remove(ns->policy_dentry);
 	securityfs_remove(violations);
 	securityfs_remove(runtime_measurements_count);
 	securityfs_remove(ascii_runtime_measurements);
 	securityfs_remove(binary_runtime_measurements);
 	securityfs_remove(ima_symlink);
 	securityfs_remove(ima_dir);
-	securityfs_remove(ima_policy);
 	return -1;
 }
+
+int __init ima_fs_init(void)
+{
+	return ima_fs_ns_init(&init_user_ns);
+}
-- 
2.31.1