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 | |
15 | static 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(to: &attributes, from: userbuf, n: 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(ptr: data)) |
37 | return PTR_ERR(ptr: data); |
38 | |
39 | bytes = efivar_entry_set_get_size(entry: var, attributes, size: &datasize, |
40 | data, set: &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, i_size: datasize + sizeof(attributes)); |
54 | inode_set_mtime_to_ts(inode, ts: inode_set_ctime_current(inode)); |
55 | inode_unlock(inode); |
56 | } |
57 | |
58 | bytes = count; |
59 | |
60 | out: |
61 | kfree(objp: data); |
62 | |
63 | return bytes; |
64 | } |
65 | |
66 | static 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(msecs: 50); |
78 | |
79 | err = efivar_entry_size(entry: var, size: &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(size: datasize + sizeof(attributes), GFP_KERNEL); |
91 | |
92 | if (!data) |
93 | return -ENOMEM; |
94 | |
95 | size = efivar_entry_get(entry: var, attributes: &attributes, size: &datasize, |
96 | data: data + sizeof(attributes)); |
97 | if (size) |
98 | goto out_free; |
99 | |
100 | memcpy(data, &attributes, sizeof(attributes)); |
101 | size = simple_read_from_buffer(to: userbuf, count, ppos, |
102 | from: data, available: datasize + sizeof(attributes)); |
103 | out_free: |
104 | kfree(objp: data); |
105 | |
106 | return size; |
107 | } |
108 | |
109 | const struct file_operations efivarfs_file_operations = { |
110 | .open = simple_open, |
111 | .read = efivarfs_file_read, |
112 | .write = efivarfs_file_write, |
113 | .llseek = no_llseek, |
114 | }; |
115 | |