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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/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// 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_unlock(inode);
55 }
56
57 bytes = count;
58
59out:
60 kfree(data);
61
62 return bytes;
63}
64
65static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
66 size_t count, loff_t *ppos)
67{
68 struct efivar_entry *var = file->private_data;
69 unsigned long datasize = 0;
70 u32 attributes;
71 void *data;
72 ssize_t size = 0;
73 int err;
74
75 while (!__ratelimit(&file->f_cred->user->ratelimit)) {
76 if (!msleep_interruptible(50))
77 return -EINTR;
78 }
79
80 err = efivar_entry_size(var, &datasize);
81
82 /*
83 * efivarfs represents uncommitted variables with
84 * zero-length files. Reading them should return EOF.
85 */
86 if (err == -ENOENT)
87 return 0;
88 else if (err)
89 return err;
90
91 data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
92
93 if (!data)
94 return -ENOMEM;
95
96 size = efivar_entry_get(var, &attributes, &datasize,
97 data + sizeof(attributes));
98 if (size)
99 goto out_free;
100
101 memcpy(data, &attributes, sizeof(attributes));
102 size = simple_read_from_buffer(userbuf, count, ppos,
103 data, datasize + sizeof(attributes));
104out_free:
105 kfree(data);
106
107 return size;
108}
109
110static inline unsigned int efivarfs_getflags(struct inode *inode)
111{
112 unsigned int i_flags;
113 unsigned int flags = 0;
114
115 i_flags = inode->i_flags;
116 if (i_flags & S_IMMUTABLE)
117 flags |= FS_IMMUTABLE_FL;
118 return flags;
119}
120
121static int
122efivarfs_ioc_getxflags(struct file *file, void __user *arg)
123{
124 struct inode *inode = file->f_mapping->host;
125 unsigned int flags = efivarfs_getflags(inode);
126
127 if (copy_to_user(arg, &flags, sizeof(flags)))
128 return -EFAULT;
129 return 0;
130}
131
132static int
133efivarfs_ioc_setxflags(struct file *file, void __user *arg)
134{
135 struct inode *inode = file->f_mapping->host;
136 unsigned int flags;
137 unsigned int i_flags = 0;
138 unsigned int oldflags = efivarfs_getflags(inode);
139 int error;
140
141 if (!inode_owner_or_capable(inode))
142 return -EACCES;
143
144 if (copy_from_user(&flags, arg, sizeof(flags)))
145 return -EFAULT;
146
147 if (flags & ~FS_IMMUTABLE_FL)
148 return -EOPNOTSUPP;
149
150 if (flags & FS_IMMUTABLE_FL)
151 i_flags |= S_IMMUTABLE;
152
153
154 error = mnt_want_write_file(file);
155 if (error)
156 return error;
157
158 inode_lock(inode);
159
160 error = vfs_ioc_setflags_prepare(inode, oldflags, flags);
161 if (error)
162 goto out;
163
164 inode_set_flags(inode, i_flags, S_IMMUTABLE);
165out:
166 inode_unlock(inode);
167 mnt_drop_write_file(file);
168 return error;
169}
170
171static long
172efivarfs_file_ioctl(struct file *file, unsigned int cmd, unsigned long p)
173{
174 void __user *arg = (void __user *)p;
175
176 switch (cmd) {
177 case FS_IOC_GETFLAGS:
178 return efivarfs_ioc_getxflags(file, arg);
179 case FS_IOC_SETFLAGS:
180 return efivarfs_ioc_setxflags(file, arg);
181 }
182
183 return -ENOTTY;
184}
185
186const struct file_operations efivarfs_file_operations = {
187 .open = simple_open,
188 .read = efivarfs_file_read,
189 .write = efivarfs_file_write,
190 .llseek = no_llseek,
191 .unlocked_ioctl = efivarfs_file_ioctl,
192};