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
|
// 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/delay.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/mount.h>
#include "internal.h"
static ssize_t efivarfs_file_write(struct file *file,
const char __user *userbuf, size_t count, loff_t *ppos)
{
struct efivar_entry *var = file->private_data;
void *data;
u32 attributes;
struct inode *inode = file->f_mapping->host;
unsigned long datasize = count - sizeof(attributes);
ssize_t bytes;
bool set = false;
if (count < sizeof(attributes))
return -EINVAL;
if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
return -EFAULT;
if (attributes & ~(EFI_VARIABLE_MASK))
return -EINVAL;
data = memdup_user(userbuf + sizeof(attributes), datasize);
if (IS_ERR(data))
return PTR_ERR(data);
bytes = efivar_entry_set_get_size(var, attributes, &datasize,
data, &set);
if (!set && bytes) {
if (bytes == -ENOENT)
bytes = -EIO;
goto out;
}
if (bytes == -ENOENT) {
drop_nlink(inode);
d_delete(file->f_path.dentry);
dput(file->f_path.dentry);
} else {
inode_lock(inode);
i_size_write(inode, datasize + sizeof(attributes));
inode_unlock(inode);
}
bytes = count;
out:
kfree(data);
return bytes;
}
static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
size_t count, loff_t *ppos)
{
struct efivar_entry *var = file->private_data;
unsigned long datasize = 0;
u32 attributes;
void *data;
ssize_t size = 0;
int err;
while (!__ratelimit(&file->f_cred->user->ratelimit)) {
if (!msleep_interruptible(50))
return -EINTR;
}
err = efivar_entry_size(var, &datasize);
/*
* efivarfs represents uncommitted variables with
* zero-length files. Reading them should return EOF.
*/
if (err == -ENOENT)
return 0;
else if (err)
return err;
data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
if (!data)
return -ENOMEM;
size = efivar_entry_get(var, &attributes, &datasize,
data + sizeof(attributes));
if (size)
goto out_free;
memcpy(data, &attributes, sizeof(attributes));
size = simple_read_from_buffer(userbuf, count, ppos,
data, datasize + sizeof(attributes));
out_free:
kfree(data);
return size;
}
static inline unsigned int efivarfs_getflags(struct inode *inode)
{
unsigned int i_flags;
unsigned int flags = 0;
i_flags = inode->i_flags;
if (i_flags & S_IMMUTABLE)
flags |= FS_IMMUTABLE_FL;
return flags;
}
static int
efivarfs_ioc_getxflags(struct file *file, void __user *arg)
{
struct inode *inode = file->f_mapping->host;
unsigned int flags = efivarfs_getflags(inode);
if (copy_to_user(arg, &flags, sizeof(flags)))
return -EFAULT;
return 0;
}
static int
efivarfs_ioc_setxflags(struct file *file, void __user *arg)
{
struct inode *inode = file->f_mapping->host;
unsigned int flags;
unsigned int i_flags = 0;
unsigned int oldflags = efivarfs_getflags(inode);
int error;
if (!inode_owner_or_capable(inode))
return -EACCES;
if (copy_from_user(&flags, arg, sizeof(flags)))
return -EFAULT;
if (flags & ~FS_IMMUTABLE_FL)
return -EOPNOTSUPP;
if (flags & FS_IMMUTABLE_FL)
i_flags |= S_IMMUTABLE;
error = mnt_want_write_file(file);
if (error)
return error;
inode_lock(inode);
error = vfs_ioc_setflags_prepare(inode, oldflags, flags);
if (error)
goto out;
inode_set_flags(inode, i_flags, S_IMMUTABLE);
out:
inode_unlock(inode);
mnt_drop_write_file(file);
return error;
}
static long
efivarfs_file_ioctl(struct file *file, unsigned int cmd, unsigned long p)
{
void __user *arg = (void __user *)p;
switch (cmd) {
case FS_IOC_GETFLAGS:
return efivarfs_ioc_getxflags(file, arg);
case FS_IOC_SETFLAGS:
return efivarfs_ioc_setxflags(file, arg);
}
return -ENOTTY;
}
const struct file_operations efivarfs_file_operations = {
.open = simple_open,
.read = efivarfs_file_read,
.write = efivarfs_file_write,
.llseek = no_llseek,
.unlocked_ioctl = efivarfs_file_ioctl,
};
|
