1d2912cb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only
2d68772b7SMatt Fleming /*
3d68772b7SMatt Fleming * Copyright (C) 2012 Red Hat, Inc.
4d68772b7SMatt Fleming * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
5d68772b7SMatt Fleming */
6d68772b7SMatt Fleming
7d68772b7SMatt Fleming #include <linux/efi.h>
8d68772b7SMatt Fleming #include <linux/fs.h>
9d68772b7SMatt Fleming #include <linux/ctype.h>
10ff04f3b6SArd Biesheuvel #include <linux/kmemleak.h>
1120b4fb48SLinus Torvalds #include <linux/slab.h>
128236431dSAndy Shevchenko #include <linux/uuid.h>
13d701ea28SMiklos Szeredi #include <linux/fileattr.h>
14d68772b7SMatt Fleming
15d68772b7SMatt Fleming #include "internal.h"
16d68772b7SMatt Fleming
17d701ea28SMiklos Szeredi static const struct inode_operations efivarfs_file_inode_operations;
18d701ea28SMiklos Szeredi
efivarfs_get_inode(struct super_block * sb,const struct inode * dir,int mode,dev_t dev,bool is_removable)19d68772b7SMatt Fleming struct inode *efivarfs_get_inode(struct super_block *sb,
20ed8b0de5SPeter Jones const struct inode *dir, int mode,
21ed8b0de5SPeter Jones dev_t dev, bool is_removable)
22d68772b7SMatt Fleming {
23d68772b7SMatt Fleming struct inode *inode = new_inode(sb);
24d68772b7SMatt Fleming
25d68772b7SMatt Fleming if (inode) {
26d68772b7SMatt Fleming inode->i_ino = get_next_ino();
27d68772b7SMatt Fleming inode->i_mode = mode;
28*2fa9a975SJeff Layton inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
29ed8b0de5SPeter Jones inode->i_flags = is_removable ? 0 : S_IMMUTABLE;
30d68772b7SMatt Fleming switch (mode & S_IFMT) {
31d68772b7SMatt Fleming case S_IFREG:
32d701ea28SMiklos Szeredi inode->i_op = &efivarfs_file_inode_operations;
33d68772b7SMatt Fleming inode->i_fop = &efivarfs_file_operations;
34d68772b7SMatt Fleming break;
35d68772b7SMatt Fleming case S_IFDIR:
36d68772b7SMatt Fleming inode->i_op = &efivarfs_dir_inode_operations;
37d68772b7SMatt Fleming inode->i_fop = &simple_dir_operations;
38d68772b7SMatt Fleming inc_nlink(inode);
39d68772b7SMatt Fleming break;
40d68772b7SMatt Fleming }
41d68772b7SMatt Fleming }
42d68772b7SMatt Fleming return inode;
43d68772b7SMatt Fleming }
44d68772b7SMatt Fleming
45d68772b7SMatt Fleming /*
46d68772b7SMatt Fleming * Return true if 'str' is a valid efivarfs filename of the form,
47d68772b7SMatt Fleming *
48d68772b7SMatt Fleming * VariableName-12345678-1234-1234-1234-1234567891bc
49d68772b7SMatt Fleming */
efivarfs_valid_name(const char * str,int len)50d68772b7SMatt Fleming bool efivarfs_valid_name(const char *str, int len)
51d68772b7SMatt Fleming {
52d68772b7SMatt Fleming const char *s = str + len - EFI_VARIABLE_GUID_LEN;
53d68772b7SMatt Fleming
54d68772b7SMatt Fleming /*
55d68772b7SMatt Fleming * We need a GUID, plus at least one letter for the variable name,
56d68772b7SMatt Fleming * plus the '-' separator
57d68772b7SMatt Fleming */
58d68772b7SMatt Fleming if (len < EFI_VARIABLE_GUID_LEN + 2)
59d68772b7SMatt Fleming return false;
60d68772b7SMatt Fleming
61d68772b7SMatt Fleming /* GUID must be preceded by a '-' */
62d68772b7SMatt Fleming if (*(s - 1) != '-')
63d68772b7SMatt Fleming return false;
64d68772b7SMatt Fleming
65d68772b7SMatt Fleming /*
66d68772b7SMatt Fleming * Validate that 's' is of the correct format, e.g.
67d68772b7SMatt Fleming *
68d68772b7SMatt Fleming * 12345678-1234-1234-1234-123456789abc
69d68772b7SMatt Fleming */
708236431dSAndy Shevchenko return uuid_is_valid(s);
71d68772b7SMatt Fleming }
72d68772b7SMatt Fleming
efivarfs_create(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode,bool excl)736c960e68SChristian Brauner static int efivarfs_create(struct mnt_idmap *idmap, struct inode *dir,
74549c7297SChristian Brauner struct dentry *dentry, umode_t mode, bool excl)
75d68772b7SMatt Fleming {
76ed8b0de5SPeter Jones struct inode *inode = NULL;
77d68772b7SMatt Fleming struct efivar_entry *var;
78d68772b7SMatt Fleming int namelen, i = 0, err = 0;
79ed8b0de5SPeter Jones bool is_removable = false;
80d68772b7SMatt Fleming
81d68772b7SMatt Fleming if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
82d68772b7SMatt Fleming return -EINVAL;
83d68772b7SMatt Fleming
84d68772b7SMatt Fleming var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
85ed8b0de5SPeter Jones if (!var)
86ed8b0de5SPeter Jones return -ENOMEM;
87d68772b7SMatt Fleming
88d68772b7SMatt Fleming /* length of the variable name itself: remove GUID and separator */
89d68772b7SMatt Fleming namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;
90d68772b7SMatt Fleming
91c4326563SAndy Shevchenko err = guid_parse(dentry->d_name.name + namelen + 1, &var->var.VendorGuid);
92c4326563SAndy Shevchenko if (err)
93c4326563SAndy Shevchenko goto out;
9463ffb573SJason A. Donenfeld if (guid_equal(&var->var.VendorGuid, &LINUX_EFI_RANDOM_SEED_TABLE_GUID)) {
9563ffb573SJason A. Donenfeld err = -EPERM;
9663ffb573SJason A. Donenfeld goto out;
9763ffb573SJason A. Donenfeld }
98d68772b7SMatt Fleming
99ed8b0de5SPeter Jones if (efivar_variable_is_removable(var->var.VendorGuid,
100ed8b0de5SPeter Jones dentry->d_name.name, namelen))
101ed8b0de5SPeter Jones is_removable = true;
102ed8b0de5SPeter Jones
103ed8b0de5SPeter Jones inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable);
104ed8b0de5SPeter Jones if (!inode) {
105ed8b0de5SPeter Jones err = -ENOMEM;
106ed8b0de5SPeter Jones goto out;
107ed8b0de5SPeter Jones }
108ed8b0de5SPeter Jones
109d68772b7SMatt Fleming for (i = 0; i < namelen; i++)
110d68772b7SMatt Fleming var->var.VariableName[i] = dentry->d_name.name[i];
111d68772b7SMatt Fleming
112d68772b7SMatt Fleming var->var.VariableName[i] = '\0';
113d68772b7SMatt Fleming
114d68772b7SMatt Fleming inode->i_private = var;
115ff04f3b6SArd Biesheuvel kmemleak_ignore(var);
116d68772b7SMatt Fleming
11721b3ddd3SSylvain Chouleur err = efivar_entry_add(var, &efivarfs_list);
11821b3ddd3SSylvain Chouleur if (err)
11921b3ddd3SSylvain Chouleur goto out;
12021b3ddd3SSylvain Chouleur
121d68772b7SMatt Fleming d_instantiate(dentry, inode);
122d68772b7SMatt Fleming dget(dentry);
123d68772b7SMatt Fleming out:
124d68772b7SMatt Fleming if (err) {
125d68772b7SMatt Fleming kfree(var);
126ed8b0de5SPeter Jones if (inode)
127d68772b7SMatt Fleming iput(inode);
128d68772b7SMatt Fleming }
129d68772b7SMatt Fleming return err;
130d68772b7SMatt Fleming }
131d68772b7SMatt Fleming
efivarfs_unlink(struct inode * dir,struct dentry * dentry)132d68772b7SMatt Fleming static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
133d68772b7SMatt Fleming {
1342b0143b5SDavid Howells struct efivar_entry *var = d_inode(dentry)->i_private;
135d68772b7SMatt Fleming
136d68772b7SMatt Fleming if (efivar_entry_delete(var))
137d68772b7SMatt Fleming return -EINVAL;
138d68772b7SMatt Fleming
1392b0143b5SDavid Howells drop_nlink(d_inode(dentry));
140d68772b7SMatt Fleming dput(dentry);
141d68772b7SMatt Fleming return 0;
142d68772b7SMatt Fleming };
143d68772b7SMatt Fleming
144d68772b7SMatt Fleming const struct inode_operations efivarfs_dir_inode_operations = {
1456e8cd2cbSAl Viro .lookup = simple_lookup,
146d68772b7SMatt Fleming .unlink = efivarfs_unlink,
147d68772b7SMatt Fleming .create = efivarfs_create,
148d68772b7SMatt Fleming };
149d701ea28SMiklos Szeredi
150d701ea28SMiklos Szeredi static int
efivarfs_fileattr_get(struct dentry * dentry,struct fileattr * fa)151d701ea28SMiklos Szeredi efivarfs_fileattr_get(struct dentry *dentry, struct fileattr *fa)
152d701ea28SMiklos Szeredi {
153d701ea28SMiklos Szeredi unsigned int i_flags;
154d701ea28SMiklos Szeredi unsigned int flags = 0;
155d701ea28SMiklos Szeredi
156d701ea28SMiklos Szeredi i_flags = d_inode(dentry)->i_flags;
157d701ea28SMiklos Szeredi if (i_flags & S_IMMUTABLE)
158d701ea28SMiklos Szeredi flags |= FS_IMMUTABLE_FL;
159d701ea28SMiklos Szeredi
160d701ea28SMiklos Szeredi fileattr_fill_flags(fa, flags);
161d701ea28SMiklos Szeredi
162d701ea28SMiklos Szeredi return 0;
163d701ea28SMiklos Szeredi }
164d701ea28SMiklos Szeredi
165d701ea28SMiklos Szeredi static int
efivarfs_fileattr_set(struct mnt_idmap * idmap,struct dentry * dentry,struct fileattr * fa)1668782a9aeSChristian Brauner efivarfs_fileattr_set(struct mnt_idmap *idmap,
167d701ea28SMiklos Szeredi struct dentry *dentry, struct fileattr *fa)
168d701ea28SMiklos Szeredi {
169d701ea28SMiklos Szeredi unsigned int i_flags = 0;
170d701ea28SMiklos Szeredi
171d701ea28SMiklos Szeredi if (fileattr_has_fsx(fa))
172d701ea28SMiklos Szeredi return -EOPNOTSUPP;
173d701ea28SMiklos Szeredi
174d701ea28SMiklos Szeredi if (fa->flags & ~FS_IMMUTABLE_FL)
175d701ea28SMiklos Szeredi return -EOPNOTSUPP;
176d701ea28SMiklos Szeredi
177d701ea28SMiklos Szeredi if (fa->flags & FS_IMMUTABLE_FL)
178d701ea28SMiklos Szeredi i_flags |= S_IMMUTABLE;
179d701ea28SMiklos Szeredi
180d701ea28SMiklos Szeredi inode_set_flags(d_inode(dentry), i_flags, S_IMMUTABLE);
181d701ea28SMiklos Szeredi
182d701ea28SMiklos Szeredi return 0;
183d701ea28SMiklos Szeredi }
184d701ea28SMiklos Szeredi
185d701ea28SMiklos Szeredi static const struct inode_operations efivarfs_file_inode_operations = {
186d701ea28SMiklos Szeredi .fileattr_get = efivarfs_fileattr_get,
187d701ea28SMiklos Szeredi .fileattr_set = efivarfs_fileattr_set,
188d701ea28SMiklos Szeredi };
189