Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  *  inode.c - securityfs
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  *  Copyright (C) 2005 Greg Kroah-Hartman <gregkh@suse.de>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  *  Based on fs/debugfs/inode.c which had the following copyright notice:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  *    Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  *    Copyright (C) 2004 IBM Inc.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) /* #define DEBUG */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <linux/sysfs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <linux/kobject.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <linux/fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <linux/fs_context.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <linux/mount.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include <linux/pagemap.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) #include <linux/namei.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) #include <linux/security.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) #include <linux/lsm_hooks.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) #include <linux/magic.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) static struct vfsmount *mount;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) static int mount_count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) static void securityfs_free_inode(struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 	if (S_ISLNK(inode->i_mode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 		kfree(inode->i_link);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 	free_inode_nonrcu(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) static const struct super_operations securityfs_super_operations = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 	.statfs		= simple_statfs,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 	.free_inode	= securityfs_free_inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) static int securityfs_fill_super(struct super_block *sb, struct fs_context *fc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 	static const struct tree_descr files[] = {{""}};
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 	int error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 	error = simple_fill_super(sb, SECURITYFS_MAGIC, files);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 	if (error)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 		return error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 	sb->s_op = &securityfs_super_operations;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) static int securityfs_get_tree(struct fs_context *fc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 	return get_tree_single(fc, securityfs_fill_super);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) static const struct fs_context_operations securityfs_context_ops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 	.get_tree	= securityfs_get_tree,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) static int securityfs_init_fs_context(struct fs_context *fc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 	fc->ops = &securityfs_context_ops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) static struct file_system_type fs_type = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 	.owner =	THIS_MODULE,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 	.name =		"securityfs",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 	.init_fs_context = securityfs_init_fs_context,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 	.kill_sb =	kill_litter_super,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77)  * securityfs_create_dentry - create a dentry in the securityfs filesystem
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79)  * @name: a pointer to a string containing the name of the file to create.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80)  * @mode: the permission that the file should have
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81)  * @parent: a pointer to the parent dentry for this file.  This should be a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82)  *          directory dentry if set.  If this parameter is %NULL, then the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83)  *          file will be created in the root of the securityfs filesystem.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84)  * @data: a pointer to something that the caller will want to get to later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85)  *        on.  The inode.i_private pointer will point to this value on
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86)  *        the open() call.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87)  * @fops: a pointer to a struct file_operations that should be used for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88)  *        this file.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89)  * @iops: a point to a struct of inode_operations that should be used for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90)  *        this file/dir
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92)  * This is the basic "create a file/dir/symlink" function for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93)  * securityfs.  It allows for a wide range of flexibility in creating
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94)  * a file, or a directory (if you want to create a directory, the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95)  * securityfs_create_dir() function is recommended to be used
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96)  * instead).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98)  * This function returns a pointer to a dentry if it succeeds.  This
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99)  * pointer must be passed to the securityfs_remove() function when the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100)  * file is to be removed (no automatic cleanup happens if your module
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101)  * is unloaded, you are responsible here).  If an error occurs, the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102)  * function will return the error value (via ERR_PTR).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104)  * If securityfs is not enabled in the kernel, the value %-ENODEV is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105)  * returned.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) static struct dentry *securityfs_create_dentry(const char *name, umode_t mode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 					struct dentry *parent, void *data,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 					const struct file_operations *fops,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 					const struct inode_operations *iops)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 	struct dentry *dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 	struct inode *dir, *inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 	int error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 	if (!(mode & S_IFMT))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 		mode = (mode & S_IALLUGO) | S_IFREG;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	pr_debug("securityfs: creating file '%s'\n",name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	error = simple_pin_fs(&fs_type, &mount, &mount_count);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	if (error)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 		return ERR_PTR(error);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 	if (!parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 		parent = mount->mnt_root;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 	dir = d_inode(parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 	inode_lock(dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 	dentry = lookup_one_len(name, parent, strlen(name));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 	if (IS_ERR(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	if (d_really_is_positive(dentry)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 		error = -EEXIST;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 		goto out1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 	inode = new_inode(dir->i_sb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	if (!inode) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 		error = -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 		goto out1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 	inode->i_ino = get_next_ino();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 	inode->i_mode = mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 	inode->i_private = data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 	if (S_ISDIR(mode)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 		inode->i_op = &simple_dir_inode_operations;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 		inode->i_fop = &simple_dir_operations;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 		inc_nlink(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 		inc_nlink(dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	} else if (S_ISLNK(mode)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 		inode->i_op = iops ? iops : &simple_symlink_inode_operations;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 		inode->i_link = data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 		inode->i_fop = fops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 	d_instantiate(dentry, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 	dget(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	inode_unlock(dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 	return dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) out1:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	dput(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 	dentry = ERR_PTR(error);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 	inode_unlock(dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 	simple_release_fs(&mount, &mount_count);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 	return dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176)  * securityfs_create_file - create a file in the securityfs filesystem
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178)  * @name: a pointer to a string containing the name of the file to create.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179)  * @mode: the permission that the file should have
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180)  * @parent: a pointer to the parent dentry for this file.  This should be a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181)  *          directory dentry if set.  If this parameter is %NULL, then the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182)  *          file will be created in the root of the securityfs filesystem.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183)  * @data: a pointer to something that the caller will want to get to later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184)  *        on.  The inode.i_private pointer will point to this value on
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185)  *        the open() call.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186)  * @fops: a pointer to a struct file_operations that should be used for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187)  *        this file.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189)  * This function creates a file in securityfs with the given @name.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191)  * This function returns a pointer to a dentry if it succeeds.  This
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192)  * pointer must be passed to the securityfs_remove() function when the file is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193)  * to be removed (no automatic cleanup happens if your module is unloaded,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194)  * you are responsible here).  If an error occurs, the function will return
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195)  * the error value (via ERR_PTR).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197)  * If securityfs is not enabled in the kernel, the value %-ENODEV is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198)  * returned.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) struct dentry *securityfs_create_file(const char *name, umode_t mode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 				      struct dentry *parent, void *data,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 				      const struct file_operations *fops)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 	return securityfs_create_dentry(name, mode, parent, data, fops, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) EXPORT_SYMBOL_GPL(securityfs_create_file);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209)  * securityfs_create_dir - create a directory in the securityfs filesystem
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211)  * @name: a pointer to a string containing the name of the directory to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212)  *        create.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213)  * @parent: a pointer to the parent dentry for this file.  This should be a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214)  *          directory dentry if set.  If this parameter is %NULL, then the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215)  *          directory will be created in the root of the securityfs filesystem.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217)  * This function creates a directory in securityfs with the given @name.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219)  * This function returns a pointer to a dentry if it succeeds.  This
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220)  * pointer must be passed to the securityfs_remove() function when the file is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221)  * to be removed (no automatic cleanup happens if your module is unloaded,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222)  * you are responsible here).  If an error occurs, the function will return
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223)  * the error value (via ERR_PTR).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225)  * If securityfs is not enabled in the kernel, the value %-ENODEV is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226)  * returned.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) struct dentry *securityfs_create_dir(const char *name, struct dentry *parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 	return securityfs_create_file(name, S_IFDIR | 0755, parent, NULL, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) EXPORT_SYMBOL_GPL(securityfs_create_dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235)  * securityfs_create_symlink - create a symlink in the securityfs filesystem
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237)  * @name: a pointer to a string containing the name of the symlink to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238)  *        create.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239)  * @parent: a pointer to the parent dentry for the symlink.  This should be a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240)  *          directory dentry if set.  If this parameter is %NULL, then the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241)  *          directory will be created in the root of the securityfs filesystem.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242)  * @target: a pointer to a string containing the name of the symlink's target.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243)  *          If this parameter is %NULL, then the @iops parameter needs to be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244)  *          setup to handle .readlink and .get_link inode_operations.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245)  * @iops: a pointer to the struct inode_operations to use for the symlink. If
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246)  *        this parameter is %NULL, then the default simple_symlink_inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247)  *        operations will be used.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249)  * This function creates a symlink in securityfs with the given @name.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251)  * This function returns a pointer to a dentry if it succeeds.  This
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252)  * pointer must be passed to the securityfs_remove() function when the file is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253)  * to be removed (no automatic cleanup happens if your module is unloaded,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254)  * you are responsible here).  If an error occurs, the function will return
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255)  * the error value (via ERR_PTR).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257)  * If securityfs is not enabled in the kernel, the value %-ENODEV is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258)  * returned.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) struct dentry *securityfs_create_symlink(const char *name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 					 struct dentry *parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 					 const char *target,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 					 const struct inode_operations *iops)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 	struct dentry *dent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 	char *link = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 	if (target) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 		link = kstrdup(target, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 		if (!link)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 			return ERR_PTR(-ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 	dent = securityfs_create_dentry(name, S_IFLNK | 0444, parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 					link, NULL, iops);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 	if (IS_ERR(dent))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 		kfree(link);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 	return dent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) EXPORT_SYMBOL_GPL(securityfs_create_symlink);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283)  * securityfs_remove - removes a file or directory from the securityfs filesystem
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285)  * @dentry: a pointer to a the dentry of the file or directory to be removed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287)  * This function removes a file or directory in securityfs that was previously
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288)  * created with a call to another securityfs function (like
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289)  * securityfs_create_file() or variants thereof.)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291)  * This function is required to be called in order for the file to be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292)  * removed. No automatic cleanup of files will happen when a module is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293)  * removed; you are responsible here.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) void securityfs_remove(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 	struct inode *dir;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 	if (!dentry || IS_ERR(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) 	dir = d_inode(dentry->d_parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) 	inode_lock(dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) 	if (simple_positive(dentry)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) 		if (d_is_dir(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 			simple_rmdir(dir, dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 		else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 			simple_unlink(dir, dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) 		dput(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) 	inode_unlock(dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) 	simple_release_fs(&mount, &mount_count);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) EXPORT_SYMBOL_GPL(securityfs_remove);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) #ifdef CONFIG_SECURITY
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) static struct dentry *lsm_dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) static ssize_t lsm_read(struct file *filp, char __user *buf, size_t count,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 			loff_t *ppos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) 	return simple_read_from_buffer(buf, count, ppos, lsm_names,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) 		strlen(lsm_names));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) static const struct file_operations lsm_ops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) 	.read = lsm_read,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) 	.llseek = generic_file_llseek,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) static int __init securityfs_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) 	int retval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) 	retval = sysfs_create_mount_point(kernel_kobj, "security");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) 	if (retval)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) 		return retval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) 	retval = register_filesystem(&fs_type);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) 	if (retval) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) 		sysfs_remove_mount_point(kernel_kobj, "security");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) 		return retval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) #ifdef CONFIG_SECURITY
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) 	lsm_dentry = securityfs_create_file("lsm", 0444, NULL, NULL,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) 						&lsm_ops);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) core_initcall(securityfs_init);