From:   Stefan Berger <stefanb@linux.ibm.com>
To:     linux-integrity@vger.kernel.org
Cc:     zohar@linux.ibm.com, serge@hallyn.com,
        christian.brauner@ubuntu.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 <stefanb@linux.ibm.com>
Subject: [RFC v2 12/19] securityfs: Pass static variables as parameters from top level functions
Date:   Thu,  2 Dec 2021 21:31:11 -0500
Message-Id: <20211203023118.1447229-13-stefanb@linux.ibm.com>
In-Reply-To: <20211203023118.1447229-1-stefanb@linux.ibm.com>
References: <20211203023118.1447229-1-stefanb@linux.ibm.com>
MIME-Version: 1.0
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Precedence: bulk

Pass the securityfs_-prefixed static variables from current top level
functions so that new APIs allow callers to pass in similar parameters and
thus share most of the existing functions.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
 security/inode.c | 92 ++++++++++++++++++++++++++++++------------------
 1 file changed, 58 insertions(+), 34 deletions(-)

diff --git a/security/inode.c b/security/inode.c
index 71d93108de55..9299f134877f 100644
--- a/security/inode.c
+++ b/security/inode.c
@@ -88,6 +88,11 @@ static struct file_system_type fs_type = {
  *        this file.
  * @iops: a point to a struct of inode_operations that should be used for
  *        this file/dir
+ * @mount: a pointer to a pointer for existing vfsmount to use or for
+ *         one to create
+ * @mount_count: pointer to integer for mount_count that goes along with
+ *               @mount
+ *
  *
  * This is the basic "create a file/dir/symlink" function for
  * securityfs.  It allows for a wide range of flexibility in creating
@@ -107,7 +112,8 @@ static struct file_system_type fs_type = {
 static struct dentry *securityfs_create_dentry(const char *name, umode_t mode,
 					struct dentry *parent, void *data,
 					const struct file_operations *fops,
-					const struct inode_operations *iops)
+					const struct inode_operations *iops,
+					struct vfsmount **mount, int *mount_count)
 {
 	struct dentry *dentry;
 	struct inode *dir, *inode;
@@ -118,12 +124,12 @@ static struct dentry *securityfs_create_dentry(const char *name, umode_t mode,
 
 	pr_debug("securityfs: creating file '%s'\n",name);
 
-	error = simple_pin_fs(&fs_type, &securityfs_mount, &securityfs_mount_count);
+	error = simple_pin_fs(&fs_type, mount, mount_count);
 	if (error)
 		return ERR_PTR(error);
 
 	if (!parent)
-		parent = securityfs_mount->mnt_root;
+		parent = (*mount)->mnt_root;
 
 	dir = d_inode(parent);
 
@@ -168,7 +174,7 @@ static struct dentry *securityfs_create_dentry(const char *name, umode_t mode,
 	dentry = ERR_PTR(error);
 out:
 	inode_unlock(dir);
-	simple_release_fs(&securityfs_mount, &securityfs_mount_count);
+	simple_release_fs(mount, mount_count);
 	return dentry;
 }
 
@@ -201,7 +207,9 @@ struct dentry *securityfs_create_file(const char *name, umode_t mode,
 				      struct dentry *parent, void *data,
 				      const struct file_operations *fops)
 {
-	return securityfs_create_dentry(name, mode, parent, data, fops, NULL);
+	return securityfs_create_dentry(name, mode, parent, data, fops, NULL,
+					&securityfs_mount,
+					&securityfs_mount_count);
 }
 EXPORT_SYMBOL_GPL(securityfs_create_file);
 
@@ -231,6 +239,27 @@ struct dentry *securityfs_create_dir(const char *name, struct dentry *parent)
 }
 EXPORT_SYMBOL_GPL(securityfs_create_dir);
 
+static struct dentry *_securityfs_create_symlink(const char *name,
+						 struct dentry *parent,
+						 const char *target,
+						 const struct inode_operations *iops,
+						 struct vfsmount **mount, int *mount_count)
+{
+	struct dentry *dent;
+	char *link = NULL;
+
+	if (target) {
+		link = kstrdup(target, GFP_KERNEL);
+		if (!link)
+			return ERR_PTR(-ENOMEM);
+	}
+	dent = securityfs_create_dentry(name, S_IFLNK | 0444, parent,
+					link, NULL, iops, mount, mount_count);
+	if (IS_ERR(dent))
+		kfree(link);
+
+	return dent;
+}
 /**
  * securityfs_create_symlink - create a symlink in the securityfs filesystem
  *
@@ -262,37 +291,13 @@ struct dentry *securityfs_create_symlink(const char *name,
 					 const char *target,
 					 const struct inode_operations *iops)
 {
-	struct dentry *dent;
-	char *link = NULL;
-
-	if (target) {
-		link = kstrdup(target, GFP_KERNEL);
-		if (!link)
-			return ERR_PTR(-ENOMEM);
-	}
-	dent = securityfs_create_dentry(name, S_IFLNK | 0444, parent,
-					link, NULL, iops);
-	if (IS_ERR(dent))
-		kfree(link);
-
-	return dent;
+	return _securityfs_create_symlink(name, parent, target, iops,
+					  &securityfs_mount, &securityfs_mount_count);
 }
 EXPORT_SYMBOL_GPL(securityfs_create_symlink);
 
-/**
- * securityfs_remove - removes a file or directory from the securityfs filesystem
- *
- * @dentry: a pointer to a the dentry of the file or directory to be removed.
- *
- * This function removes a file or directory in securityfs that was previously
- * created with a call to another securityfs function (like
- * securityfs_create_file() or variants thereof.)
- *
- * This function is required to be called in order for the file to be
- * removed. No automatic cleanup of files will happen when a module is
- * removed; you are responsible here.
- */
-void securityfs_remove(struct dentry *dentry)
+static void _securityfs_remove(struct dentry *dentry,
+			       struct vfsmount **mount, int *mount_count)
 {
 	struct inode *dir;
 
@@ -309,8 +314,27 @@ void securityfs_remove(struct dentry *dentry)
 		dput(dentry);
 	}
 	inode_unlock(dir);
-	simple_release_fs(&securityfs_mount, &securityfs_mount_count);
+	simple_release_fs(mount, mount_count);
+}
+
+/**
+ * securityfs_remove - removes a file or directory from the securityfs filesystem
+ *
+ * @dentry: a pointer to a the dentry of the file or directory to be removed.
+ *
+ * This function removes a file or directory in securityfs that was previously
+ * created with a call to another securityfs function (like
+ * securityfs_create_file() or variants thereof.)
+ *
+ * This function is required to be called in order for the file to be
+ * removed. No automatic cleanup of files will happen when a module is
+ * removed; you are responsible here.
+ */
+void securityfs_remove(struct dentry *dentry)
+{
+	_securityfs_remove(dentry, &securityfs_mount, &securityfs_mount_count);
 }
+
 EXPORT_SYMBOL_GPL(securityfs_remove);
 
 #ifdef CONFIG_SECURITY
-- 
2.31.1