1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2012 Red Hat, Inc.
  4 * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
  5 */
  6
  7#include <linux/efi.h>
  8#include <linux/fs.h>
  9#include <linux/ctype.h>
 10#include <linux/kmemleak.h>
 11#include <linux/slab.h>
 12#include <linux/uuid.h>
 13#include <linux/fileattr.h>
 14
 15#include "internal.h"
 16
 17static const struct inode_operations efivarfs_file_inode_operations;
 18
 19struct inode *efivarfs_get_inode(struct super_block *sb,
 20				const struct inode *dir, int mode,
 21				dev_t dev, bool is_removable)
 22{
 23	struct inode *inode = new_inode(sb);
 24	struct efivarfs_fs_info *fsi = sb->s_fs_info;
 25	struct efivarfs_mount_opts *opts = &fsi->mount_opts;
 26
 27	if (inode) {
 28		inode->i_uid = opts->uid;
 29		inode->i_gid = opts->gid;
 30		inode->i_ino = get_next_ino();
 31		inode->i_mode = mode;
 32		simple_inode_init_ts(inode);
 33		inode->i_flags = is_removable ? 0 : S_IMMUTABLE;
 34		switch (mode & S_IFMT) {
 35		case S_IFREG:
 36			inode->i_op = &efivarfs_file_inode_operations;
 37			inode->i_fop = &efivarfs_file_operations;
 38			break;
 39		case S_IFDIR:
 40			inode->i_op = &efivarfs_dir_inode_operations;
 41			inode->i_fop = &simple_dir_operations;
 42			inc_nlink(inode);
 43			break;
 44		}
 45	}
 46	return inode;
 47}
 48
 49/*
 50 * Return true if 'str' is a valid efivarfs filename of the form,
 51 *
 52 *	VariableName-12345678-1234-1234-1234-1234567891bc
 53 */
 54static bool efivarfs_valid_name(const char *str, int len)
 55{
 56	const char *s = str + len - EFI_VARIABLE_GUID_LEN;
 57
 58	/*
 59	 * We need a GUID, plus at least one letter for the variable name,
 60	 * plus the '-' separator
 61	 */
 62	if (len < EFI_VARIABLE_GUID_LEN + 2)
 63		return false;
 64
 65	/* GUID must be preceded by a '-' */
 66	if (*(s - 1) != '-')
 67		return false;
 68
 69	/*
 70	 * Validate that 's' is of the correct format, e.g.
 71	 *
 72	 *	12345678-1234-1234-1234-123456789abc
 73	 */
 74	return uuid_is_valid(s);
 75}
 76
 77static int efivarfs_create(struct mnt_idmap *idmap, struct inode *dir,
 78			   struct dentry *dentry, umode_t mode, bool excl)
 79{
 80	struct efivarfs_fs_info *info = dir->i_sb->s_fs_info;
 81	struct inode *inode = NULL;
 82	struct efivar_entry *var;
 83	int namelen, i = 0, err = 0;
 84	bool is_removable = false;
 85
 86	if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
 87		return -EINVAL;
 88
 89	var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
 90	if (!var)
 91		return -ENOMEM;
 92
 93	/* length of the variable name itself: remove GUID and separator */
 94	namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;
 95
 96	err = guid_parse(dentry->d_name.name + namelen + 1, &var->var.VendorGuid);
 97	if (err)
 98		goto out;
 99	if (guid_equal(&var->var.VendorGuid, &LINUX_EFI_RANDOM_SEED_TABLE_GUID)) {
100		err = -EPERM;
101		goto out;
102	}
103
104	if (efivar_variable_is_removable(var->var.VendorGuid,
105					 dentry->d_name.name, namelen))
106		is_removable = true;
107
108	inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable);
109	if (!inode) {
110		err = -ENOMEM;
111		goto out;
112	}
113
114	for (i = 0; i < namelen; i++)
115		var->var.VariableName[i] = dentry->d_name.name[i];
116
117	var->var.VariableName[i] = '\0';
118
119	inode->i_private = var;
120	kmemleak_ignore(var);
121
122	err = efivar_entry_add(var, &info->efivarfs_list);
123	if (err)
124		goto out;
125
126	d_instantiate(dentry, inode);
127	dget(dentry);
128out:
129	if (err) {
130		kfree(var);
131		if (inode)
132			iput(inode);
133	}
134	return err;
135}
136
137static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
138{
139	struct efivar_entry *var = d_inode(dentry)->i_private;
140
141	if (efivar_entry_delete(var))
142		return -EINVAL;
143
144	drop_nlink(d_inode(dentry));
145	dput(dentry);
146	return 0;
147};
148
149const struct inode_operations efivarfs_dir_inode_operations = {
150	.lookup = simple_lookup,
151	.unlink = efivarfs_unlink,
152	.create = efivarfs_create,
153};
154
155static int
156efivarfs_fileattr_get(struct dentry *dentry, struct fileattr *fa)
157{
158	unsigned int i_flags;
159	unsigned int flags = 0;
160
161	i_flags = d_inode(dentry)->i_flags;
162	if (i_flags & S_IMMUTABLE)
163		flags |= FS_IMMUTABLE_FL;
164
165	fileattr_fill_flags(fa, flags);
166
167	return 0;
168}
169
170static int
171efivarfs_fileattr_set(struct mnt_idmap *idmap,
172		      struct dentry *dentry, struct fileattr *fa)
173{
174	unsigned int i_flags = 0;
175
176	if (fileattr_has_fsx(fa))
177		return -EOPNOTSUPP;
178
179	if (fa->flags & ~FS_IMMUTABLE_FL)
180		return -EOPNOTSUPP;
181
182	if (fa->flags & FS_IMMUTABLE_FL)
183		i_flags |= S_IMMUTABLE;
184
185	inode_set_flags(d_inode(dentry), i_flags, S_IMMUTABLE);
186
187	return 0;
188}
189
190static const struct inode_operations efivarfs_file_inode_operations = {
191	.fileattr_get = efivarfs_fileattr_get,
192	.fileattr_set = efivarfs_fileattr_set,
193};

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2012 Red Hat, Inc.
  4 * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
  5 */
  6
  7#include <linux/efi.h>
  8#include <linux/fs.h>
  9#include <linux/ctype.h>
 10#include <linux/kmemleak.h>
 11#include <linux/slab.h>
 12#include <linux/uuid.h>
 13#include <linux/fileattr.h>
 14
 15#include "internal.h"
 16
 17static const struct inode_operations efivarfs_file_inode_operations;
 18
 19struct inode *efivarfs_get_inode(struct super_block *sb,
 20				const struct inode *dir, int mode,
 21				dev_t dev, bool is_removable)
 22{
 23	struct inode *inode = new_inode(sb);
 
 
 24
 25	if (inode) {
 
 
 26		inode->i_ino = get_next_ino();
 27		inode->i_mode = mode;
 28		inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 29		inode->i_flags = is_removable ? 0 : S_IMMUTABLE;
 30		switch (mode & S_IFMT) {
 31		case S_IFREG:
 32			inode->i_op = &efivarfs_file_inode_operations;
 33			inode->i_fop = &efivarfs_file_operations;
 34			break;
 35		case S_IFDIR:
 36			inode->i_op = &efivarfs_dir_inode_operations;
 37			inode->i_fop = &simple_dir_operations;
 38			inc_nlink(inode);
 39			break;
 40		}
 41	}
 42	return inode;
 43}
 44
 45/*
 46 * Return true if 'str' is a valid efivarfs filename of the form,
 47 *
 48 *	VariableName-12345678-1234-1234-1234-1234567891bc
 49 */
 50bool efivarfs_valid_name(const char *str, int len)
 51{
 52	const char *s = str + len - EFI_VARIABLE_GUID_LEN;
 53
 54	/*
 55	 * We need a GUID, plus at least one letter for the variable name,
 56	 * plus the '-' separator
 57	 */
 58	if (len < EFI_VARIABLE_GUID_LEN + 2)
 59		return false;
 60
 61	/* GUID must be preceded by a '-' */
 62	if (*(s - 1) != '-')
 63		return false;
 64
 65	/*
 66	 * Validate that 's' is of the correct format, e.g.
 67	 *
 68	 *	12345678-1234-1234-1234-123456789abc
 69	 */
 70	return uuid_is_valid(s);
 71}
 72
 73static int efivarfs_create(struct user_namespace *mnt_userns, struct inode *dir,
 74			   struct dentry *dentry, umode_t mode, bool excl)
 75{
 
 76	struct inode *inode = NULL;
 77	struct efivar_entry *var;
 78	int namelen, i = 0, err = 0;
 79	bool is_removable = false;
 80
 81	if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
 82		return -EINVAL;
 83
 84	var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
 85	if (!var)
 86		return -ENOMEM;
 87
 88	/* length of the variable name itself: remove GUID and separator */
 89	namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;
 90
 91	err = guid_parse(dentry->d_name.name + namelen + 1, &var->var.VendorGuid);
 92	if (err)
 93		goto out;
 
 
 
 
 94
 95	if (efivar_variable_is_removable(var->var.VendorGuid,
 96					 dentry->d_name.name, namelen))
 97		is_removable = true;
 98
 99	inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable);
100	if (!inode) {
101		err = -ENOMEM;
102		goto out;
103	}
104
105	for (i = 0; i < namelen; i++)
106		var->var.VariableName[i] = dentry->d_name.name[i];
107
108	var->var.VariableName[i] = '\0';
109
110	inode->i_private = var;
111	kmemleak_ignore(var);
112
113	err = efivar_entry_add(var, &efivarfs_list);
114	if (err)
115		goto out;
116
117	d_instantiate(dentry, inode);
118	dget(dentry);
119out:
120	if (err) {
121		kfree(var);
122		if (inode)
123			iput(inode);
124	}
125	return err;
126}
127
128static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
129{
130	struct efivar_entry *var = d_inode(dentry)->i_private;
131
132	if (efivar_entry_delete(var))
133		return -EINVAL;
134
135	drop_nlink(d_inode(dentry));
136	dput(dentry);
137	return 0;
138};
139
140const struct inode_operations efivarfs_dir_inode_operations = {
141	.lookup = simple_lookup,
142	.unlink = efivarfs_unlink,
143	.create = efivarfs_create,
144};
145
146static int
147efivarfs_fileattr_get(struct dentry *dentry, struct fileattr *fa)
148{
149	unsigned int i_flags;
150	unsigned int flags = 0;
151
152	i_flags = d_inode(dentry)->i_flags;
153	if (i_flags & S_IMMUTABLE)
154		flags |= FS_IMMUTABLE_FL;
155
156	fileattr_fill_flags(fa, flags);
157
158	return 0;
159}
160
161static int
162efivarfs_fileattr_set(struct user_namespace *mnt_userns,
163		      struct dentry *dentry, struct fileattr *fa)
164{
165	unsigned int i_flags = 0;
166
167	if (fileattr_has_fsx(fa))
168		return -EOPNOTSUPP;
169
170	if (fa->flags & ~FS_IMMUTABLE_FL)
171		return -EOPNOTSUPP;
172
173	if (fa->flags & FS_IMMUTABLE_FL)
174		i_flags |= S_IMMUTABLE;
175
176	inode_set_flags(d_inode(dentry), i_flags, S_IMMUTABLE);
177
178	return 0;
179}
180
181static const struct inode_operations efivarfs_file_inode_operations = {
182	.fileattr_get = efivarfs_fileattr_get,
183	.fileattr_set = efivarfs_fileattr_set,
184};