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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
d68772b7 MF |
2 | /* |
3 | * Copyright (C) 2012 Red Hat, Inc. | |
4 | * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com> | |
d68772b7 MF |
5 | */ |
6 | ||
7 | #include <linux/efi.h> | |
8 | #include <linux/fs.h> | |
9 | #include <linux/ctype.h> | |
ff04f3b6 | 10 | #include <linux/kmemleak.h> |
20b4fb48 | 11 | #include <linux/slab.h> |
8236431d | 12 | #include <linux/uuid.h> |
d701ea28 | 13 | #include <linux/fileattr.h> |
d68772b7 MF |
14 | |
15 | #include "internal.h" | |
16 | ||
d701ea28 MS |
17 | static const struct inode_operations efivarfs_file_inode_operations; |
18 | ||
d68772b7 | 19 | struct inode *efivarfs_get_inode(struct super_block *sb, |
ed8b0de5 PJ |
20 | const struct inode *dir, int mode, |
21 | dev_t dev, bool is_removable) | |
d68772b7 MF |
22 | { |
23 | struct inode *inode = new_inode(sb); | |
24 | ||
25 | if (inode) { | |
26 | inode->i_ino = get_next_ino(); | |
27 | inode->i_mode = mode; | |
078cd827 | 28 | inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
ed8b0de5 | 29 | inode->i_flags = is_removable ? 0 : S_IMMUTABLE; |
d68772b7 MF |
30 | switch (mode & S_IFMT) { |
31 | case S_IFREG: | |
d701ea28 | 32 | inode->i_op = &efivarfs_file_inode_operations; |
d68772b7 MF |
33 | inode->i_fop = &efivarfs_file_operations; |
34 | break; | |
35 | case S_IFDIR: | |
36 | inode->i_op = &efivarfs_dir_inode_operations; | |
37 | inode->i_fop = &simple_dir_operations; | |
38 | inc_nlink(inode); | |
39 | break; | |
40 | } | |
41 | } | |
42 | return inode; | |
43 | } | |
44 | ||
45 | /* | |
46 | * Return true if 'str' is a valid efivarfs filename of the form, | |
47 | * | |
48 | * VariableName-12345678-1234-1234-1234-1234567891bc | |
49 | */ | |
50 | bool efivarfs_valid_name(const char *str, int len) | |
51 | { | |
d68772b7 | 52 | const char *s = str + len - EFI_VARIABLE_GUID_LEN; |
d68772b7 MF |
53 | |
54 | /* | |
55 | * We need a GUID, plus at least one letter for the variable name, | |
56 | * plus the '-' separator | |
57 | */ | |
58 | if (len < EFI_VARIABLE_GUID_LEN + 2) | |
59 | return false; | |
60 | ||
61 | /* GUID must be preceded by a '-' */ | |
62 | if (*(s - 1) != '-') | |
63 | return false; | |
64 | ||
65 | /* | |
66 | * Validate that 's' is of the correct format, e.g. | |
67 | * | |
68 | * 12345678-1234-1234-1234-123456789abc | |
69 | */ | |
8236431d | 70 | return uuid_is_valid(s); |
d68772b7 MF |
71 | } |
72 | ||
549c7297 CB |
73 | static int efivarfs_create(struct user_namespace *mnt_userns, struct inode *dir, |
74 | struct dentry *dentry, umode_t mode, bool excl) | |
d68772b7 | 75 | { |
ed8b0de5 | 76 | struct inode *inode = NULL; |
d68772b7 MF |
77 | struct efivar_entry *var; |
78 | int namelen, i = 0, err = 0; | |
ed8b0de5 | 79 | bool is_removable = false; |
d68772b7 MF |
80 | |
81 | if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len)) | |
82 | return -EINVAL; | |
83 | ||
d68772b7 | 84 | var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL); |
ed8b0de5 PJ |
85 | if (!var) |
86 | return -ENOMEM; | |
d68772b7 MF |
87 | |
88 | /* length of the variable name itself: remove GUID and separator */ | |
89 | namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1; | |
90 | ||
c4326563 AS |
91 | err = guid_parse(dentry->d_name.name + namelen + 1, &var->var.VendorGuid); |
92 | if (err) | |
93 | goto out; | |
d68772b7 | 94 | |
ed8b0de5 PJ |
95 | if (efivar_variable_is_removable(var->var.VendorGuid, |
96 | dentry->d_name.name, namelen)) | |
97 | is_removable = true; | |
98 | ||
99 | inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable); | |
100 | if (!inode) { | |
101 | err = -ENOMEM; | |
102 | goto out; | |
103 | } | |
104 | ||
d68772b7 MF |
105 | for (i = 0; i < namelen; i++) |
106 | var->var.VariableName[i] = dentry->d_name.name[i]; | |
107 | ||
108 | var->var.VariableName[i] = '\0'; | |
109 | ||
110 | inode->i_private = var; | |
ff04f3b6 | 111 | kmemleak_ignore(var); |
d68772b7 | 112 | |
21b3ddd3 SC |
113 | err = efivar_entry_add(var, &efivarfs_list); |
114 | if (err) | |
115 | goto out; | |
116 | ||
d68772b7 MF |
117 | d_instantiate(dentry, inode); |
118 | dget(dentry); | |
119 | out: | |
120 | if (err) { | |
121 | kfree(var); | |
ed8b0de5 PJ |
122 | if (inode) |
123 | iput(inode); | |
d68772b7 MF |
124 | } |
125 | return err; | |
126 | } | |
127 | ||
128 | static int efivarfs_unlink(struct inode *dir, struct dentry *dentry) | |
129 | { | |
2b0143b5 | 130 | struct efivar_entry *var = d_inode(dentry)->i_private; |
d68772b7 MF |
131 | |
132 | if (efivar_entry_delete(var)) | |
133 | return -EINVAL; | |
134 | ||
2b0143b5 | 135 | drop_nlink(d_inode(dentry)); |
d68772b7 MF |
136 | dput(dentry); |
137 | return 0; | |
138 | }; | |
139 | ||
d68772b7 | 140 | const struct inode_operations efivarfs_dir_inode_operations = { |
6e8cd2cb | 141 | .lookup = simple_lookup, |
d68772b7 MF |
142 | .unlink = efivarfs_unlink, |
143 | .create = efivarfs_create, | |
144 | }; | |
d701ea28 MS |
145 | |
146 | static int | |
147 | efivarfs_fileattr_get(struct dentry *dentry, struct fileattr *fa) | |
148 | { | |
149 | unsigned int i_flags; | |
150 | unsigned int flags = 0; | |
151 | ||
152 | i_flags = d_inode(dentry)->i_flags; | |
153 | if (i_flags & S_IMMUTABLE) | |
154 | flags |= FS_IMMUTABLE_FL; | |
155 | ||
156 | fileattr_fill_flags(fa, flags); | |
157 | ||
158 | return 0; | |
159 | } | |
160 | ||
161 | static int | |
162 | efivarfs_fileattr_set(struct user_namespace *mnt_userns, | |
163 | struct dentry *dentry, struct fileattr *fa) | |
164 | { | |
165 | unsigned int i_flags = 0; | |
166 | ||
167 | if (fileattr_has_fsx(fa)) | |
168 | return -EOPNOTSUPP; | |
169 | ||
170 | if (fa->flags & ~FS_IMMUTABLE_FL) | |
171 | return -EOPNOTSUPP; | |
172 | ||
173 | if (fa->flags & FS_IMMUTABLE_FL) | |
174 | i_flags |= S_IMMUTABLE; | |
175 | ||
176 | inode_set_flags(d_inode(dentry), i_flags, S_IMMUTABLE); | |
177 | ||
178 | return 0; | |
179 | } | |
180 | ||
181 | static const struct inode_operations efivarfs_file_inode_operations = { | |
182 | .fileattr_get = efivarfs_fileattr_get, | |
183 | .fileattr_set = efivarfs_fileattr_set, | |
184 | }; |