Commit | Line | Data |
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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); | |
5329aa51 JZ |
24 | struct efivarfs_fs_info *fsi = sb->s_fs_info; |
25 | struct efivarfs_mount_opts *opts = &fsi->mount_opts; | |
d68772b7 MF |
26 | |
27 | if (inode) { | |
5329aa51 JZ |
28 | inode->i_uid = opts->uid; |
29 | inode->i_gid = opts->gid; | |
d68772b7 MF |
30 | inode->i_ino = get_next_ino(); |
31 | inode->i_mode = mode; | |
2fa9a975 | 32 | inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode); |
ed8b0de5 | 33 | inode->i_flags = is_removable ? 0 : S_IMMUTABLE; |
d68772b7 MF |
34 | switch (mode & S_IFMT) { |
35 | case S_IFREG: | |
d701ea28 | 36 | inode->i_op = &efivarfs_file_inode_operations; |
d68772b7 MF |
37 | inode->i_fop = &efivarfs_file_operations; |
38 | break; | |
39 | case S_IFDIR: | |
40 | inode->i_op = &efivarfs_dir_inode_operations; | |
41 | inode->i_fop = &simple_dir_operations; | |
42 | inc_nlink(inode); | |
43 | break; | |
44 | } | |
45 | } | |
46 | return inode; | |
47 | } | |
48 | ||
49 | /* | |
50 | * Return true if 'str' is a valid efivarfs filename of the form, | |
51 | * | |
52 | * VariableName-12345678-1234-1234-1234-1234567891bc | |
53 | */ | |
54 | bool efivarfs_valid_name(const char *str, int len) | |
55 | { | |
d68772b7 | 56 | const char *s = str + len - EFI_VARIABLE_GUID_LEN; |
d68772b7 MF |
57 | |
58 | /* | |
59 | * We need a GUID, plus at least one letter for the variable name, | |
60 | * plus the '-' separator | |
61 | */ | |
62 | if (len < EFI_VARIABLE_GUID_LEN + 2) | |
63 | return false; | |
64 | ||
65 | /* GUID must be preceded by a '-' */ | |
66 | if (*(s - 1) != '-') | |
67 | return false; | |
68 | ||
69 | /* | |
70 | * Validate that 's' is of the correct format, e.g. | |
71 | * | |
72 | * 12345678-1234-1234-1234-123456789abc | |
73 | */ | |
8236431d | 74 | return uuid_is_valid(s); |
d68772b7 MF |
75 | } |
76 | ||
6c960e68 | 77 | static int efivarfs_create(struct mnt_idmap *idmap, struct inode *dir, |
549c7297 | 78 | struct dentry *dentry, umode_t mode, bool excl) |
d68772b7 | 79 | { |
ed8b0de5 | 80 | struct inode *inode = NULL; |
d68772b7 MF |
81 | struct efivar_entry *var; |
82 | int namelen, i = 0, err = 0; | |
ed8b0de5 | 83 | bool is_removable = false; |
d68772b7 MF |
84 | |
85 | if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len)) | |
86 | return -EINVAL; | |
87 | ||
d68772b7 | 88 | var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL); |
ed8b0de5 PJ |
89 | if (!var) |
90 | return -ENOMEM; | |
d68772b7 MF |
91 | |
92 | /* length of the variable name itself: remove GUID and separator */ | |
93 | namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1; | |
94 | ||
c4326563 AS |
95 | err = guid_parse(dentry->d_name.name + namelen + 1, &var->var.VendorGuid); |
96 | if (err) | |
97 | goto out; | |
63ffb573 JD |
98 | if (guid_equal(&var->var.VendorGuid, &LINUX_EFI_RANDOM_SEED_TABLE_GUID)) { |
99 | err = -EPERM; | |
100 | goto out; | |
101 | } | |
d68772b7 | 102 | |
ed8b0de5 PJ |
103 | if (efivar_variable_is_removable(var->var.VendorGuid, |
104 | dentry->d_name.name, namelen)) | |
105 | is_removable = true; | |
106 | ||
107 | inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable); | |
108 | if (!inode) { | |
109 | err = -ENOMEM; | |
110 | goto out; | |
111 | } | |
112 | ||
d68772b7 MF |
113 | for (i = 0; i < namelen; i++) |
114 | var->var.VariableName[i] = dentry->d_name.name[i]; | |
115 | ||
116 | var->var.VariableName[i] = '\0'; | |
117 | ||
118 | inode->i_private = var; | |
ff04f3b6 | 119 | kmemleak_ignore(var); |
d68772b7 | 120 | |
21b3ddd3 SC |
121 | err = efivar_entry_add(var, &efivarfs_list); |
122 | if (err) | |
123 | goto out; | |
124 | ||
d68772b7 MF |
125 | d_instantiate(dentry, inode); |
126 | dget(dentry); | |
127 | out: | |
128 | if (err) { | |
129 | kfree(var); | |
ed8b0de5 PJ |
130 | if (inode) |
131 | iput(inode); | |
d68772b7 MF |
132 | } |
133 | return err; | |
134 | } | |
135 | ||
136 | static int efivarfs_unlink(struct inode *dir, struct dentry *dentry) | |
137 | { | |
2b0143b5 | 138 | struct efivar_entry *var = d_inode(dentry)->i_private; |
d68772b7 MF |
139 | |
140 | if (efivar_entry_delete(var)) | |
141 | return -EINVAL; | |
142 | ||
2b0143b5 | 143 | drop_nlink(d_inode(dentry)); |
d68772b7 MF |
144 | dput(dentry); |
145 | return 0; | |
146 | }; | |
147 | ||
d68772b7 | 148 | const struct inode_operations efivarfs_dir_inode_operations = { |
6e8cd2cb | 149 | .lookup = simple_lookup, |
d68772b7 MF |
150 | .unlink = efivarfs_unlink, |
151 | .create = efivarfs_create, | |
152 | }; | |
d701ea28 MS |
153 | |
154 | static int | |
155 | efivarfs_fileattr_get(struct dentry *dentry, struct fileattr *fa) | |
156 | { | |
157 | unsigned int i_flags; | |
158 | unsigned int flags = 0; | |
159 | ||
160 | i_flags = d_inode(dentry)->i_flags; | |
161 | if (i_flags & S_IMMUTABLE) | |
162 | flags |= FS_IMMUTABLE_FL; | |
163 | ||
164 | fileattr_fill_flags(fa, flags); | |
165 | ||
166 | return 0; | |
167 | } | |
168 | ||
169 | static int | |
8782a9ae | 170 | efivarfs_fileattr_set(struct mnt_idmap *idmap, |
d701ea28 MS |
171 | struct dentry *dentry, struct fileattr *fa) |
172 | { | |
173 | unsigned int i_flags = 0; | |
174 | ||
175 | if (fileattr_has_fsx(fa)) | |
176 | return -EOPNOTSUPP; | |
177 | ||
178 | if (fa->flags & ~FS_IMMUTABLE_FL) | |
179 | return -EOPNOTSUPP; | |
180 | ||
181 | if (fa->flags & FS_IMMUTABLE_FL) | |
182 | i_flags |= S_IMMUTABLE; | |
183 | ||
184 | inode_set_flags(d_inode(dentry), i_flags, S_IMMUTABLE); | |
185 | ||
186 | return 0; | |
187 | } | |
188 | ||
189 | static const struct inode_operations efivarfs_file_inode_operations = { | |
190 | .fileattr_get = efivarfs_fileattr_get, | |
191 | .fileattr_set = efivarfs_fileattr_set, | |
192 | }; |