1 files changed, 234 insertions, 0 deletions
diff --git a/security/inode.c b/security/inode.c
new file mode 100644
index 000000000..0e37e4fba
--- /dev/null
+++ b/security/inode.c
@@ -0,0 +1,234 @@
+/*
+ *  inode.c - securityfs
+ *
+ *  Copyright (C) 2005 Greg Kroah-Hartman <gregkh@suse.de>
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License version
+ *	2 as published by the Free Software Foundation.
+ *
+ *  Based on fs/debugfs/inode.c which had the following copyright notice:
+ *    Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
+ *    Copyright (C) 2004 IBM Inc.
+ */
+
+/* #define DEBUG */
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/pagemap.h>
+#include <linux/init.h>
+#include <linux/namei.h>
+#include <linux/security.h>
+#include <linux/magic.h>
+
+static struct vfsmount *mount;
+static int mount_count;
+
+static inline int positive(struct dentry *dentry)
+{
+	return d_really_is_positive(dentry) && !d_unhashed(dentry);
+}
+
+static int fill_super(struct super_block *sb, void *data, int silent)
+{
+	static struct tree_descr files[] = {{""}};
+
+	return simple_fill_super(sb, SECURITYFS_MAGIC, files);
+}
+
+static struct dentry *get_sb(struct file_system_type *fs_type,
+		  int flags, const char *dev_name,
+		  void *data)
+{
+	return mount_single(fs_type, flags, data, fill_super);
+}
+
+static struct file_system_type fs_type = {
+	.owner =	THIS_MODULE,
+	.name =		"securityfs",
+	.mount =	get_sb,
+	.kill_sb =	kill_litter_super,
+};
+
+/**
+ * securityfs_create_file - create a file in the securityfs filesystem
+ *
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the securityfs filesystem.
+ * @data: a pointer to something that the caller will want to get to later
+ *        on.  The inode.i_private pointer will point to this value on
+ *        the open() call.
+ * @fops: a pointer to a struct file_operations that should be used for
+ *        this file.
+ *
+ * This is the basic "create a file" function for securityfs.  It allows for a
+ * wide range of flexibility in creating a file, or a directory (if you
+ * want to create a directory, the securityfs_create_dir() function is
+ * recommended to be used instead).
+ *
+ * This function returns a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the securityfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here).  If an error occurs, the function will return
+ * the error value (via ERR_PTR).
+ *
+ * If securityfs is not enabled in the kernel, the value %-ENODEV is
+ * returned.
+ */
+struct dentry *securityfs_create_file(const char *name, umode_t mode,
+				   struct dentry *parent, void *data,
+				   const struct file_operations *fops)
+{
+	struct dentry *dentry;
+	int is_dir = S_ISDIR(mode);
+	struct inode *dir, *inode;
+	int error;
+
+	if (!is_dir) {
+		BUG_ON(!fops);
+		mode = (mode & S_IALLUGO) | S_IFREG;
+	}
+
+	pr_debug("securityfs: creating file '%s'\n",name);
+
+	error = simple_pin_fs(&fs_type, &mount, &mount_count);
+	if (error)
+		return ERR_PTR(error);
+
+	if (!parent)
+		parent = mount->mnt_root;
+
+	dir = d_inode(parent);
+
+	mutex_lock(&dir->i_mutex);
+	dentry = lookup_one_len(name, parent, strlen(name));
+	if (IS_ERR(dentry))
+		goto out;
+
+	if (d_really_is_positive(dentry)) {
+		error = -EEXIST;
+		goto out1;
+	}
+
+	inode = new_inode(dir->i_sb);
+	if (!inode) {
+		error = -ENOMEM;
+		goto out1;
+	}
+
+	inode->i_ino = get_next_ino();
+	inode->i_mode = mode;
+	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+	inode->i_private = data;
+	if (is_dir) {
+		inode->i_op = &simple_dir_inode_operations;
+		inode->i_fop = &simple_dir_operations;
+		inc_nlink(inode);
+		inc_nlink(dir);
+	} else {
+		inode->i_fop = fops;
+	}
+	d_instantiate(dentry, inode);
+	dget(dentry);
+	mutex_unlock(&dir->i_mutex);
+	return dentry;
+
+out1:
+	dput(dentry);
+	dentry = ERR_PTR(error);
+out:
+	mutex_unlock(&dir->i_mutex);
+	simple_release_fs(&mount, &mount_count);
+	return dentry;
+}
+EXPORT_SYMBOL_GPL(securityfs_create_file);
+
+/**
+ * securityfs_create_dir - create a directory in the securityfs filesystem
+ *
+ * @name: a pointer to a string containing the name of the directory to
+ *        create.
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          directory will be created in the root of the securityfs filesystem.
+ *
+ * This function creates a directory in securityfs with the given @name.
+ *
+ * This function returns a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the securityfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here).  If an error occurs, %NULL will be returned.
+ *
+ * If securityfs is not enabled in the kernel, the value %-ENODEV is
+ * returned.  It is not wise to check for this value, but rather, check for
+ * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
+ * code.
+ */
+struct dentry *securityfs_create_dir(const char *name, struct dentry *parent)
+{
+	return securityfs_create_file(name,
+				      S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
+				      parent, NULL, NULL);
+}
+EXPORT_SYMBOL_GPL(securityfs_create_dir);
+
+/**
+ * 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)
+{
+	struct dentry *parent;
+
+	if (!dentry || IS_ERR(dentry))
+		return;
+
+	parent = dentry->d_parent;
+	if (!parent || d_really_is_negative(parent))
+		return;
+
+	mutex_lock(&d_inode(parent)->i_mutex);
+	if (positive(dentry)) {
+		if (d_really_is_positive(dentry)) {
+			if (d_is_dir(dentry))
+				simple_rmdir(d_inode(parent), dentry);
+			else
+				simple_unlink(d_inode(parent), dentry);
+			dput(dentry);
+		}
+	}
+	mutex_unlock(&d_inode(parent)->i_mutex);
+	simple_release_fs(&mount, &mount_count);
+}
+EXPORT_SYMBOL_GPL(securityfs_remove);
+
+static int __init securityfs_init(void)
+{
+	int retval;
+
+	retval = sysfs_create_mount_point(kernel_kobj, "security");
+	if (retval)
+		return retval;
+
+	retval = register_filesystem(&fs_type);
+	if (retval)
+		sysfs_remove_mount_point(kernel_kobj, "security");
+	return retval;
+}
+
+core_initcall(securityfs_init);
+MODULE_LICENSE("GPL");
+