1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
|
/*
* Copyright (C) 2016 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdlib.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/asn1.h>
#include <ipxe/der.h>
#include <ipxe/uaccess.h>
#include <ipxe/image.h>
/** @file
*
* DER-encoded ASN.1 data
*
*/
/**
* Extract ASN.1 object from image
*
* @v image DER image
* @v offset Offset within image
* @v cursor ASN.1 cursor to fill in
* @ret next Offset to next image, or negative error
*
* The caller is responsible for eventually calling free() on the
* allocated ASN.1 cursor.
*/
static int der_asn1 ( struct image *image, size_t offset __unused,
struct asn1_cursor **cursor ) {
void *data;
/* Allocate cursor and data buffer */
*cursor = malloc ( sizeof ( **cursor ) + image->len );
if ( ! *cursor )
return -ENOMEM;
data = ( ( ( void * ) *cursor ) + sizeof ( **cursor ) );
/* Populate cursor and data buffer */
(*cursor)->data = data;
(*cursor)->len = image->len;
copy_from_user ( data, image->data, 0, image->len );
return image->len;
}
/**
* Probe DER image
*
* @v image DER image
* @ret rc Return status code
*/
static int der_probe ( struct image *image ) {
struct asn1_cursor cursor;
uint8_t buf[8];
size_t extra;
size_t total;
int len;
int rc;
/* Sanity check: no realistic DER image can be smaller than this */
if ( image->len < sizeof ( buf ) )
return -ENOEXEC;
/* Prepare partial cursor */
cursor.data = buf;
cursor.len = sizeof ( buf );
copy_from_user ( buf, image->data, 0, sizeof ( buf ) );
extra = ( image->len - sizeof ( buf ) );
/* Get length of ASN.1 sequence */
len = asn1_start ( &cursor, ASN1_SEQUENCE, extra );
if ( len < 0 ) {
rc = len;
DBGC ( image, "DER %s is not valid ASN.1: %s\n",
image->name, strerror ( rc ) );
return rc;
}
/* Add length of tag and length bytes consumed by asn1_start() */
total = ( len + ( cursor.data - ( ( void * ) buf ) ) );
assert ( total <= image->len );
/* Check that image comprises a single well-formed ASN.1 object */
if ( total != image->len ) {
DBGC ( image, "DER %s is not single ASN.1\n", image->name );
return -ENOEXEC;
}
return 0;
}
/** DER image type */
struct image_type der_image_type __image_type ( PROBE_NORMAL ) = {
.name = "DER",
.probe = der_probe,
.asn1 = der_asn1,
};
|
