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