1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2012 Red Hat, Inc.
4 * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
9 #include <linux/ctype.h>
10 #include <linux/kmemleak.h>
11 #include <linux/slab.h>
12 #include <linux/uuid.h>
13 #include <linux/fileattr.h>
17 static const struct inode_operations efivarfs_file_inode_operations
;
19 struct inode
*efivarfs_get_inode(struct super_block
*sb
,
20 const struct inode
*dir
, int mode
,
21 dev_t dev
, bool is_removable
)
23 struct inode
*inode
= new_inode(sb
);
26 inode
->i_ino
= get_next_ino();
28 inode
->i_atime
= inode
->i_mtime
= inode
->i_ctime
= current_time(inode
);
29 inode
->i_flags
= is_removable
? 0 : S_IMMUTABLE
;
30 switch (mode
& S_IFMT
) {
32 inode
->i_op
= &efivarfs_file_inode_operations
;
33 inode
->i_fop
= &efivarfs_file_operations
;
36 inode
->i_op
= &efivarfs_dir_inode_operations
;
37 inode
->i_fop
= &simple_dir_operations
;
46 * Return true if 'str' is a valid efivarfs filename of the form,
48 * VariableName-12345678-1234-1234-1234-1234567891bc
50 bool efivarfs_valid_name(const char *str
, int len
)
52 const char *s
= str
+ len
- EFI_VARIABLE_GUID_LEN
;
55 * We need a GUID, plus at least one letter for the variable name,
56 * plus the '-' separator
58 if (len
< EFI_VARIABLE_GUID_LEN
+ 2)
61 /* GUID must be preceded by a '-' */
66 * Validate that 's' is of the correct format, e.g.
68 * 12345678-1234-1234-1234-123456789abc
70 return uuid_is_valid(s
);
73 static int efivarfs_create(struct user_namespace
*mnt_userns
, struct inode
*dir
,
74 struct dentry
*dentry
, umode_t mode
, bool excl
)
76 struct inode
*inode
= NULL
;
77 struct efivar_entry
*var
;
78 int namelen
, i
= 0, err
= 0;
79 bool is_removable
= false;
81 if (!efivarfs_valid_name(dentry
->d_name
.name
, dentry
->d_name
.len
))
84 var
= kzalloc(sizeof(struct efivar_entry
), GFP_KERNEL
);
88 /* length of the variable name itself: remove GUID and separator */
89 namelen
= dentry
->d_name
.len
- EFI_VARIABLE_GUID_LEN
- 1;
91 err
= guid_parse(dentry
->d_name
.name
+ namelen
+ 1, &var
->var
.VendorGuid
);
95 if (efivar_variable_is_removable(var
->var
.VendorGuid
,
96 dentry
->d_name
.name
, namelen
))
99 inode
= efivarfs_get_inode(dir
->i_sb
, dir
, mode
, 0, is_removable
);
105 for (i
= 0; i
< namelen
; i
++)
106 var
->var
.VariableName
[i
] = dentry
->d_name
.name
[i
];
108 var
->var
.VariableName
[i
] = '\0';
110 inode
->i_private
= var
;
111 kmemleak_ignore(var
);
113 err
= efivar_entry_add(var
, &efivarfs_list
);
117 d_instantiate(dentry
, inode
);
128 static int efivarfs_unlink(struct inode
*dir
, struct dentry
*dentry
)
130 struct efivar_entry
*var
= d_inode(dentry
)->i_private
;
132 if (efivar_entry_delete(var
))
135 drop_nlink(d_inode(dentry
));
140 const struct inode_operations efivarfs_dir_inode_operations
= {
141 .lookup
= simple_lookup
,
142 .unlink
= efivarfs_unlink
,
143 .create
= efivarfs_create
,
147 efivarfs_fileattr_get(struct dentry
*dentry
, struct fileattr
*fa
)
149 unsigned int i_flags
;
150 unsigned int flags
= 0;
152 i_flags
= d_inode(dentry
)->i_flags
;
153 if (i_flags
& S_IMMUTABLE
)
154 flags
|= FS_IMMUTABLE_FL
;
156 fileattr_fill_flags(fa
, flags
);
162 efivarfs_fileattr_set(struct user_namespace
*mnt_userns
,
163 struct dentry
*dentry
, struct fileattr
*fa
)
165 unsigned int i_flags
= 0;
167 if (fileattr_has_fsx(fa
))
170 if (fa
->flags
& ~FS_IMMUTABLE_FL
)
173 if (fa
->flags
& FS_IMMUTABLE_FL
)
174 i_flags
|= S_IMMUTABLE
;
176 inode_set_flags(d_inode(dentry
), i_flags
, S_IMMUTABLE
);
181 static const struct inode_operations efivarfs_file_inode_operations
= {
182 .fileattr_get
= efivarfs_fileattr_get
,
183 .fileattr_set
= efivarfs_fileattr_set
,