Loading...
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/delay.h>
9#include <linux/fs.h>
10#include <linux/slab.h>
11#include <linux/mount.h>
12
13#include "internal.h"
14
15static ssize_t efivarfs_file_write(struct file *file,
16 const char __user *userbuf, size_t count, loff_t *ppos)
17{
18 struct efivar_entry *var = file->private_data;
19 void *data;
20 u32 attributes;
21 struct inode *inode = file->f_mapping->host;
22 unsigned long datasize = count - sizeof(attributes);
23 ssize_t bytes;
24 bool set = false;
25
26 if (count < sizeof(attributes))
27 return -EINVAL;
28
29 if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
30 return -EFAULT;
31
32 if (attributes & ~(EFI_VARIABLE_MASK))
33 return -EINVAL;
34
35 data = memdup_user(userbuf + sizeof(attributes), datasize);
36 if (IS_ERR(data))
37 return PTR_ERR(data);
38
39 bytes = efivar_entry_set_get_size(var, attributes, &datasize,
40 data, &set);
41 if (!set && bytes) {
42 if (bytes == -ENOENT)
43 bytes = -EIO;
44 goto out;
45 }
46
47 if (bytes == -ENOENT) {
48 drop_nlink(inode);
49 d_delete(file->f_path.dentry);
50 dput(file->f_path.dentry);
51 } else {
52 inode_lock(inode);
53 i_size_write(inode, datasize + sizeof(attributes));
54 inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
55 inode_unlock(inode);
56 }
57
58 bytes = count;
59
60out:
61 kfree(data);
62
63 return bytes;
64}
65
66static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
67 size_t count, loff_t *ppos)
68{
69 struct efivar_entry *var = file->private_data;
70 unsigned long datasize = 0;
71 u32 attributes;
72 void *data;
73 ssize_t size = 0;
74 int err;
75
76 while (!__ratelimit(&file->f_cred->user->ratelimit))
77 msleep(50);
78
79 err = efivar_entry_size(var, &datasize);
80
81 /*
82 * efivarfs represents uncommitted variables with
83 * zero-length files. Reading them should return EOF.
84 */
85 if (err == -ENOENT)
86 return 0;
87 else if (err)
88 return err;
89
90 data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
91
92 if (!data)
93 return -ENOMEM;
94
95 size = efivar_entry_get(var, &attributes, &datasize,
96 data + sizeof(attributes));
97 if (size)
98 goto out_free;
99
100 memcpy(data, &attributes, sizeof(attributes));
101 size = simple_read_from_buffer(userbuf, count, ppos,
102 data, datasize + sizeof(attributes));
103out_free:
104 kfree(data);
105
106 return size;
107}
108
109const struct file_operations efivarfs_file_operations = {
110 .open = simple_open,
111 .read = efivarfs_file_read,
112 .write = efivarfs_file_write,
113};
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/slab.h>
13#include <linux/mount.h>
14
15#include "internal.h"
16
17static ssize_t efivarfs_file_write(struct file *file,
18 const char __user *userbuf, size_t count, loff_t *ppos)
19{
20 struct efivar_entry *var = file->private_data;
21 void *data;
22 u32 attributes;
23 struct inode *inode = file->f_mapping->host;
24 unsigned long datasize = count - sizeof(attributes);
25 ssize_t bytes;
26 bool set = false;
27
28 if (count < sizeof(attributes))
29 return -EINVAL;
30
31 if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
32 return -EFAULT;
33
34 if (attributes & ~(EFI_VARIABLE_MASK))
35 return -EINVAL;
36
37 data = memdup_user(userbuf + sizeof(attributes), datasize);
38 if (IS_ERR(data))
39 return PTR_ERR(data);
40
41 bytes = efivar_entry_set_get_size(var, attributes, &datasize,
42 data, &set);
43 if (!set && bytes) {
44 if (bytes == -ENOENT)
45 bytes = -EIO;
46 goto out;
47 }
48
49 if (bytes == -ENOENT) {
50 drop_nlink(inode);
51 d_delete(file->f_path.dentry);
52 dput(file->f_path.dentry);
53 } else {
54 inode_lock(inode);
55 i_size_write(inode, datasize + sizeof(attributes));
56 inode_unlock(inode);
57 }
58
59 bytes = count;
60
61out:
62 kfree(data);
63
64 return bytes;
65}
66
67static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
68 size_t count, loff_t *ppos)
69{
70 struct efivar_entry *var = file->private_data;
71 unsigned long datasize = 0;
72 u32 attributes;
73 void *data;
74 ssize_t size = 0;
75 int err;
76
77 err = efivar_entry_size(var, &datasize);
78
79 /*
80 * efivarfs represents uncommitted variables with
81 * zero-length files. Reading them should return EOF.
82 */
83 if (err == -ENOENT)
84 return 0;
85 else if (err)
86 return err;
87
88 data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
89
90 if (!data)
91 return -ENOMEM;
92
93 size = efivar_entry_get(var, &attributes, &datasize,
94 data + sizeof(attributes));
95 if (size)
96 goto out_free;
97
98 memcpy(data, &attributes, sizeof(attributes));
99 size = simple_read_from_buffer(userbuf, count, ppos,
100 data, datasize + sizeof(attributes));
101out_free:
102 kfree(data);
103
104 return size;
105}
106
107static int
108efivarfs_ioc_getxflags(struct file *file, void __user *arg)
109{
110 struct inode *inode = file->f_mapping->host;
111 unsigned int i_flags;
112 unsigned int flags = 0;
113
114 i_flags = inode->i_flags;
115 if (i_flags & S_IMMUTABLE)
116 flags |= FS_IMMUTABLE_FL;
117
118 if (copy_to_user(arg, &flags, sizeof(flags)))
119 return -EFAULT;
120 return 0;
121}
122
123static int
124efivarfs_ioc_setxflags(struct file *file, void __user *arg)
125{
126 struct inode *inode = file->f_mapping->host;
127 unsigned int flags;
128 unsigned int i_flags = 0;
129 int error;
130
131 if (!inode_owner_or_capable(inode))
132 return -EACCES;
133
134 if (copy_from_user(&flags, arg, sizeof(flags)))
135 return -EFAULT;
136
137 if (flags & ~FS_IMMUTABLE_FL)
138 return -EOPNOTSUPP;
139
140 if (!capable(CAP_LINUX_IMMUTABLE))
141 return -EPERM;
142
143 if (flags & FS_IMMUTABLE_FL)
144 i_flags |= S_IMMUTABLE;
145
146
147 error = mnt_want_write_file(file);
148 if (error)
149 return error;
150
151 inode_lock(inode);
152 inode_set_flags(inode, i_flags, S_IMMUTABLE);
153 inode_unlock(inode);
154
155 mnt_drop_write_file(file);
156
157 return 0;
158}
159
160static long
161efivarfs_file_ioctl(struct file *file, unsigned int cmd, unsigned long p)
162{
163 void __user *arg = (void __user *)p;
164
165 switch (cmd) {
166 case FS_IOC_GETFLAGS:
167 return efivarfs_ioc_getxflags(file, arg);
168 case FS_IOC_SETFLAGS:
169 return efivarfs_ioc_setxflags(file, arg);
170 }
171
172 return -ENOTTY;
173}
174
175const struct file_operations efivarfs_file_operations = {
176 .open = simple_open,
177 .read = efivarfs_file_read,
178 .write = efivarfs_file_write,
179 .llseek = no_llseek,
180 .unlocked_ioctl = efivarfs_file_ioctl,
181};