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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/*
2 * Copyright (C) 2012 Red Hat, Inc.
3 * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 */
9
10#include <linux/efi.h>
11#include <linux/fs.h>
12#include <linux/ctype.h>
13#include <linux/slab.h>
14#include <linux/uuid.h>
15
16#include "internal.h"
17
18struct inode *efivarfs_get_inode(struct super_block *sb,
19 const struct inode *dir, int mode,
20 dev_t dev, bool is_removable)
21{
22 struct inode *inode = new_inode(sb);
23
24 if (inode) {
25 inode->i_ino = get_next_ino();
26 inode->i_mode = mode;
27 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
28 inode->i_flags = is_removable ? 0 : S_IMMUTABLE;
29 switch (mode & S_IFMT) {
30 case S_IFREG:
31 inode->i_fop = &efivarfs_file_operations;
32 break;
33 case S_IFDIR:
34 inode->i_op = &efivarfs_dir_inode_operations;
35 inode->i_fop = &simple_dir_operations;
36 inc_nlink(inode);
37 break;
38 }
39 }
40 return inode;
41}
42
43/*
44 * Return true if 'str' is a valid efivarfs filename of the form,
45 *
46 * VariableName-12345678-1234-1234-1234-1234567891bc
47 */
48bool efivarfs_valid_name(const char *str, int len)
49{
50 const char *s = str + len - EFI_VARIABLE_GUID_LEN;
51
52 /*
53 * We need a GUID, plus at least one letter for the variable name,
54 * plus the '-' separator
55 */
56 if (len < EFI_VARIABLE_GUID_LEN + 2)
57 return false;
58
59 /* GUID must be preceded by a '-' */
60 if (*(s - 1) != '-')
61 return false;
62
63 /*
64 * Validate that 's' is of the correct format, e.g.
65 *
66 * 12345678-1234-1234-1234-123456789abc
67 */
68 return uuid_is_valid(s);
69}
70
71static int efivarfs_create(struct inode *dir, struct dentry *dentry,
72 umode_t mode, bool excl)
73{
74 struct inode *inode = NULL;
75 struct efivar_entry *var;
76 int namelen, i = 0, err = 0;
77 bool is_removable = false;
78
79 if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
80 return -EINVAL;
81
82 var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
83 if (!var)
84 return -ENOMEM;
85
86 /* length of the variable name itself: remove GUID and separator */
87 namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;
88
89 uuid_le_to_bin(dentry->d_name.name + namelen + 1, &var->var.VendorGuid);
90
91 if (efivar_variable_is_removable(var->var.VendorGuid,
92 dentry->d_name.name, namelen))
93 is_removable = true;
94
95 inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable);
96 if (!inode) {
97 err = -ENOMEM;
98 goto out;
99 }
100
101 for (i = 0; i < namelen; i++)
102 var->var.VariableName[i] = dentry->d_name.name[i];
103
104 var->var.VariableName[i] = '\0';
105
106 inode->i_private = var;
107
108 err = efivar_entry_add(var, &efivarfs_list);
109 if (err)
110 goto out;
111
112 d_instantiate(dentry, inode);
113 dget(dentry);
114out:
115 if (err) {
116 kfree(var);
117 if (inode)
118 iput(inode);
119 }
120 return err;
121}
122
123static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
124{
125 struct efivar_entry *var = d_inode(dentry)->i_private;
126
127 if (efivar_entry_delete(var))
128 return -EINVAL;
129
130 drop_nlink(d_inode(dentry));
131 dput(dentry);
132 return 0;
133};
134
135const struct inode_operations efivarfs_dir_inode_operations = {
136 .lookup = simple_lookup,
137 .unlink = efivarfs_unlink,
138 .create = efivarfs_create,
139};