[mirror_ubuntu-zesty-kernel.git] / security / inode.c

/*
 *  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 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,
};

int securityfs_pin_fs(void)
{
	return simple_pin_fs(&fs_type, &mount, &mount_count);
}

int __securityfs_setup_d_inode(struct inode *dir, struct dentry *dentry,
			       umode_t mode, void *data,
			       const struct file_operations *fops,
			       const struct inode_operations *iops)
{
	bool is_dir = S_ISDIR(mode);
	struct inode *inode = new_inode(dir->i_sb);
	if (!inode)
		return -ENOMEM;

	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 = iops ? iops : &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);

	return 0;
}
EXPORT_SYMBOL_GPL(__securityfs_setup_d_inode);

/**
 * securityfs_create_dentry - create a file/dir 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.
 * @iops: a point to a struct of inode_operations that should be used for
 *        this file/dir
 *
 * This is the basic "create a xxx" 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_dentry(const char *name, umode_t mode,
					struct dentry *parent, void *data,
					const struct file_operations *fops,
					const struct inode_operations *iops)
{
	struct dentry *dentry;
	int is_dir = S_ISDIR(mode);
	struct inode *dir;
	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);

	inode_lock(dir);
	dentry = lookup_one_len(name, parent, strlen(name));
	if (IS_ERR(dentry))
		goto out;

	if (d_really_is_positive(dentry)) {
		error = -EEXIST;
		goto out1;
	}

	error = __securityfs_setup_d_inode(dir, dentry, mode, data, fops, iops);
	if (error)
		goto out1;
	inode_unlock(dir);
	return dentry;

out1:
	dput(dentry);
	dentry = ERR_PTR(error);
out:
	inode_unlock(dir);
	simple_release_fs(&mount, &mount_count);
	return dentry;
}
EXPORT_SYMBOL_GPL(securityfs_create_dentry);

/**
 * 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 function creates a file 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, 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)
{
	return securityfs_create_dentry(name, mode, parent, data, fops, NULL);
}
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, 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_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 inode *dir;

	if (!dentry || IS_ERR(dentry))
		return;

	dir = d_inode(dentry->d_parent);
	inode_lock(dir);
	if (simple_positive(dentry)) {
		if (d_is_dir(dentry))
			simple_rmdir(dir, dentry);
		else
			simple_unlink(dir, dentry);
		dput(dentry);
	}
	inode_unlock(dir);
	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");
Commit	Line	Data
b67dbf9d GKH	1	/*
	2	* inode.c - securityfs
	3	*
	4	* Copyright (C) 2005 Greg Kroah-Hartman <gregkh@suse.de>
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License version
	8	* 2 as published by the Free Software Foundation.
	9	*
	10	* Based on fs/debugfs/inode.c which had the following copyright notice:
	11	* Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
	12	* Copyright (C) 2004 IBM Inc.
	13	*/
	14
	15	/* #define DEBUG */
b67dbf9d GKH	16	#include <linux/module.h>
	17	#include <linux/fs.h>
	18	#include <linux/mount.h>
	19	#include <linux/pagemap.h>
	20	#include <linux/init.h>
	21	#include <linux/namei.h>
	22	#include <linux/security.h>
92562927	23	#include <linux/magic.h>
b67dbf9d GKH	24
	25	static struct vfsmount *mount;
	26	static int mount_count;
	27
b67dbf9d GKH	28	static int fill_super(struct super_block sb, void data, int silent)
	29	{
	30	static struct tree_descr files[] = {{""}};
	31
	32	return simple_fill_super(sb, SECURITYFS_MAGIC, files);
	33	}
	34
fc14f2fe	35	static struct dentry get_sb(struct file_system_type fs_type,
454e2398	36	int flags, const char *dev_name,
fc14f2fe	37	void *data)
b67dbf9d	38	{
fc14f2fe	39	return mount_single(fs_type, flags, data, fill_super);
b67dbf9d GKH	40	}
	41
	42	static struct file_system_type fs_type = {
	43	.owner = THIS_MODULE,
	44	.name = "securityfs",
fc14f2fe	45	.mount = get_sb,
b67dbf9d GKH	46	.kill_sb = kill_litter_super,
	47	};
	48
8e8739b6 JJ	49	int securityfs_pin_fs(void)
	50	{
	51	return simple_pin_fs(&fs_type, &mount, &mount_count);
	52	}
	53
	54	int __securityfs_setup_d_inode(struct inode dir, struct dentry dentry,
	55	umode_t mode, void *data,
	56	const struct file_operations *fops,
	57	const struct inode_operations *iops)
	58	{
	59	bool is_dir = S_ISDIR(mode);
	60	struct inode *inode = new_inode(dir->i_sb);
	61	if (!inode)
	62	return -ENOMEM;
	63
	64	inode->i_ino = get_next_ino();
	65	inode->i_mode = mode;
	66	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
	67	inode->i_private = data;
	68	if (is_dir) {
	69	inode->i_op = iops ? iops : &simple_dir_inode_operations;
	70	inode->i_fop = &simple_dir_operations;
	71	inc_nlink(inode);
	72	inc_nlink(dir);
	73	} else {
	74	inode->i_fop = fops;
	75	}
	76	d_instantiate(dentry, inode);
	77	dget(dentry);
	78
	79	return 0;
	80	}
	81	EXPORT_SYMBOL_GPL(__securityfs_setup_d_inode);
	82
b67dbf9d	83	/**
8e8739b6	84	* securityfs_create_dentry - create a file/dir in the securityfs filesystem
b67dbf9d GKH	85	*
	86	* @name: a pointer to a string containing the name of the file to create.
	87	* @mode: the permission that the file should have
	88	* @parent: a pointer to the parent dentry for this file. This should be a
3f23d815	89	* directory dentry if set. If this parameter is %NULL, then the
b67dbf9d GKH	90	* file will be created in the root of the securityfs filesystem.
b67dbf9d GKH	91	* @data: a pointer to something that the caller will want to get to later
8e18e294	92	* on. The inode.i_private pointer will point to this value on
b67dbf9d GKH	93	* the open() call.
	94	* @fops: a pointer to a struct file_operations that should be used for
	95	* this file.
8e8739b6 JJ	96	* @iops: a point to a struct of inode_operations that should be used for
8e8739b6 JJ	97	* this file/dir
b67dbf9d	98	*
8e8739b6	99	* This is the basic "create a xxx" function for securityfs. It allows for a
3f23d815	100	* wide range of flexibility in creating a file, or a directory (if you
b67dbf9d	101	* want to create a directory, the securityfs_create_dir() function is
3f23d815	102	* recommended to be used instead).
b67dbf9d	103	*
3f23d815	104	* This function returns a pointer to a dentry if it succeeds. This
b67dbf9d GKH	105	* pointer must be passed to the securityfs_remove() function when the file is
b67dbf9d GKH	106	* to be removed (no automatic cleanup happens if your module is unloaded,
faa3aad7	107	* you are responsible here). If an error occurs, the function will return
da3dae54	108	* the error value (via ERR_PTR).
b67dbf9d	109	*
3f23d815	110	* If securityfs is not enabled in the kernel, the value %-ENODEV is
faa3aad7	111	* returned.
b67dbf9d	112	*/
8e8739b6 JJ	113	struct dentry securityfs_create_dentry(const char name, umode_t mode,
	114	struct dentry parent, void data,
	115	const struct file_operations *fops,
	116	const struct inode_operations *iops)
b67dbf9d	117	{
3e25eb9c AV	118	struct dentry *dentry;
3e25eb9c AV	119	int is_dir = S_ISDIR(mode);
8e8739b6	120	struct inode *dir;
b67dbf9d GKH	121	int error;
b67dbf9d GKH	122
3e25eb9c AV	123	if (!is_dir) {
	124	BUG_ON(!fops);
	125	mode = (mode & S_IALLUGO) \| S_IFREG;
	126	}
	127
b67dbf9d GKH	128	pr_debug("securityfs: creating file '%s'\n",name);
b67dbf9d GKH	129
1f5ce9e9	130	error = simple_pin_fs(&fs_type, &mount, &mount_count);
3e25eb9c AV	131	if (error)
	132	return ERR_PTR(error);
	133
	134	if (!parent)
	135	parent = mount->mnt_root;
	136
ce0b16dd	137	dir = d_inode(parent);
3e25eb9c	138
5955102c	139	inode_lock(dir);
3e25eb9c AV	140	dentry = lookup_one_len(name, parent, strlen(name));
	141	if (IS_ERR(dentry))
	142	goto out;
	143
ce0b16dd	144	if (d_really_is_positive(dentry)) {
3e25eb9c AV	145	error = -EEXIST;
3e25eb9c AV	146	goto out1;
b67dbf9d GKH	147	}
b67dbf9d GKH	148
8e8739b6 JJ	149	error = __securityfs_setup_d_inode(dir, dentry, mode, data, fops, iops);
8e8739b6 JJ	150	if (error)
3e25eb9c	151	goto out1;
5955102c	152	inode_unlock(dir);
3e25eb9c AV	153	return dentry;
	154
	155	out1:
	156	dput(dentry);
	157	dentry = ERR_PTR(error);
	158	out:
5955102c	159	inode_unlock(dir);
3e25eb9c	160	simple_release_fs(&mount, &mount_count);
b67dbf9d GKH	161	return dentry;
b67dbf9d GKH	162	}
8e8739b6 JJ	163	EXPORT_SYMBOL_GPL(securityfs_create_dentry);
	164
	165	/**
	166	* securityfs_create_file - create a file in the securityfs filesystem
	167	*
	168	* @name: a pointer to a string containing the name of the file to create.
	169	* @mode: the permission that the file should have
	170	* @parent: a pointer to the parent dentry for this file. This should be a
	171	* directory dentry if set. If this parameter is %NULL, then the
	172	* file will be created in the root of the securityfs filesystem.
	173	* @data: a pointer to something that the caller will want to get to later
	174	* on. The inode.i_private pointer will point to this value on
	175	* the open() call.
	176	* @fops: a pointer to a struct file_operations that should be used for
	177	* this file.
	178	*
	179	* This function creates a file in securityfs with the given @name.
	180	*
	181	* This function returns a pointer to a dentry if it succeeds. This
	182	* pointer must be passed to the securityfs_remove() function when the file is
	183	* to be removed (no automatic cleanup happens if your module is unloaded,
	184	* you are responsible here). If an error occurs, the function will return
	185	* the error value (via ERR_PTR).
	186	*
	187	* If securityfs is not enabled in the kernel, the value %-ENODEV is
	188	* returned.
	189	*/
	190	struct dentry securityfs_create_file(const char name, umode_t mode,
	191	struct dentry parent, void data,
	192	const struct file_operations *fops)
	193	{
	194	return securityfs_create_dentry(name, mode, parent, data, fops, NULL);
	195	}
b67dbf9d GKH	196	EXPORT_SYMBOL_GPL(securityfs_create_file);
	197
	198	/**
	199	* securityfs_create_dir - create a directory in the securityfs filesystem
	200	*
	201	* @name: a pointer to a string containing the name of the directory to
	202	* create.
	203	* @parent: a pointer to the parent dentry for this file. This should be a
3f23d815	204	* directory dentry if set. If this parameter is %NULL, then the
b67dbf9d GKH	205	* directory will be created in the root of the securityfs filesystem.
b67dbf9d GKH	206	*
3f23d815	207	* This function creates a directory in securityfs with the given @name.
b67dbf9d	208	*
3f23d815	209	* This function returns a pointer to a dentry if it succeeds. This
b67dbf9d GKH	210	* pointer must be passed to the securityfs_remove() function when the file is
b67dbf9d GKH	211	* to be removed (no automatic cleanup happens if your module is unloaded,
1b460651 LG	212	* you are responsible here). If an error occurs, the function will return
1b460651 LG	213	* the error value (via ERR_PTR).
b67dbf9d	214	*
3f23d815	215	* If securityfs is not enabled in the kernel, the value %-ENODEV is
1b460651	216	* returned.
b67dbf9d GKH	217	*/
	218	struct dentry securityfs_create_dir(const char name, struct dentry *parent)
	219	{
	220	return securityfs_create_file(name,
	221	S_IFDIR \| S_IRWXU \| S_IRUGO \| S_IXUGO,
	222	parent, NULL, NULL);
	223	}
	224	EXPORT_SYMBOL_GPL(securityfs_create_dir);
	225
	226	/**
	227	* securityfs_remove - removes a file or directory from the securityfs filesystem
	228	*
3f23d815	229	* @dentry: a pointer to a the dentry of the file or directory to be removed.
b67dbf9d GKH	230	*
	231	* This function removes a file or directory in securityfs that was previously
	232	* created with a call to another securityfs function (like
	233	* securityfs_create_file() or variants thereof.)
	234	*
	235	* This function is required to be called in order for the file to be
3f23d815 RD	236	* removed. No automatic cleanup of files will happen when a module is
3f23d815 RD	237	* removed; you are responsible here.
b67dbf9d GKH	238	*/
	239	void securityfs_remove(struct dentry *dentry)
	240	{
4093d306	241	struct inode *dir;
b67dbf9d	242
d93e4c94	243	if (!dentry \|\| IS_ERR(dentry))
b67dbf9d GKH	244	return;
b67dbf9d GKH	245
4093d306 AV	246	dir = d_inode(dentry->d_parent);
4093d306 AV	247	inode_lock(dir);
dc3f4198 AV	248	if (simple_positive(dentry)) {
dc3f4198 AV	249	if (d_is_dir(dentry))
4093d306	250	simple_rmdir(dir, dentry);
dc3f4198	251	else
4093d306	252	simple_unlink(dir, dentry);
dc3f4198	253	dput(dentry);
b67dbf9d	254	}
4093d306	255	inode_unlock(dir);
b67dbf9d GKH	256	simple_release_fs(&mount, &mount_count);
	257	}
	258	EXPORT_SYMBOL_GPL(securityfs_remove);
	259
b67dbf9d GKH	260	static int __init securityfs_init(void)
	261	{
	262	int retval;
	263
f9bb4882 EB	264	retval = sysfs_create_mount_point(kernel_kobj, "security");
	265	if (retval)
	266	return retval;
b67dbf9d GKH	267
	268	retval = register_filesystem(&fs_type);
	269	if (retval)
f9bb4882	270	sysfs_remove_mount_point(kernel_kobj, "security");
b67dbf9d GKH	271	return retval;
	272	}
	273
b67dbf9d	274	core_initcall(securityfs_init);
b67dbf9d GKH	275	MODULE_LICENSE("GPL");
b67dbf9d GKH	276