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
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
|
/*
* Copyright (C) 2007 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <ipxe/asn1.h>
#include <ipxe/x509.h>
/** @file
*
* X.509 certificates
*
* The structure of X.509v3 certificates is concisely documented in
* RFC5280 section 4.1. The structure of RSA public keys is
* documented in RFC2313.
*/
/** Object Identifier for "rsaEncryption" (1.2.840.113549.1.1.1) */
static const uint8_t oid_rsa_encryption[] = { 0x2a, 0x86, 0x48, 0x86, 0xf7,
0x0d, 0x01, 0x01, 0x01 };
/**
* Identify X.509 certificate public key
*
* @v certificate Certificate
* @v algorithm Public key algorithm to fill in
* @v pubkey Public key value to fill in
* @ret rc Return status code
*/
static int x509_public_key ( const struct asn1_cursor *certificate,
struct asn1_cursor *algorithm,
struct asn1_cursor *pubkey ) {
struct asn1_cursor cursor;
int rc;
/* Locate subjectPublicKeyInfo */
memcpy ( &cursor, certificate, sizeof ( cursor ) );
rc = ( asn1_enter ( &cursor, ASN1_SEQUENCE ), /* Certificate */
asn1_enter ( &cursor, ASN1_SEQUENCE ), /* tbsCertificate */
asn1_skip ( &cursor, ASN1_EXPLICIT_TAG ), /* version */
asn1_skip ( &cursor, ASN1_INTEGER ), /* serialNumber */
asn1_skip ( &cursor, ASN1_SEQUENCE ), /* signature */
asn1_skip ( &cursor, ASN1_SEQUENCE ), /* issuer */
asn1_skip ( &cursor, ASN1_SEQUENCE ), /* validity */
asn1_skip ( &cursor, ASN1_SEQUENCE ), /* name */
asn1_enter ( &cursor, ASN1_SEQUENCE )/* subjectPublicKeyInfo*/);
if ( rc != 0 ) {
DBG ( "Cannot locate subjectPublicKeyInfo in:\n" );
DBG_HDA ( 0, certificate->data, certificate->len );
return rc;
}
/* Locate algorithm */
memcpy ( algorithm, &cursor, sizeof ( *algorithm ) );
rc = ( asn1_enter ( algorithm, ASN1_SEQUENCE ) /* algorithm */ );
if ( rc != 0 ) {
DBG ( "Cannot locate algorithm in:\n" );
DBG_HDA ( 0, certificate->data, certificate->len );
return rc;
}
/* Locate subjectPublicKey */
memcpy ( pubkey, &cursor, sizeof ( *pubkey ) );
rc = ( asn1_skip ( pubkey, ASN1_SEQUENCE ), /* algorithm */
asn1_enter ( pubkey, ASN1_BIT_STRING ) /* subjectPublicKey*/ );
if ( rc != 0 ) {
DBG ( "Cannot locate subjectPublicKey in:\n" );
DBG_HDA ( 0, certificate->data, certificate->len );
return rc;
}
return 0;
}
/**
* Identify X.509 certificate RSA modulus and public exponent
*
* @v certificate Certificate
* @v rsa RSA public key to fill in
* @ret rc Return status code
*
* The caller is responsible for eventually calling
* x509_free_rsa_public_key() to free the storage allocated to hold
* the RSA modulus and exponent.
*/
int x509_rsa_public_key ( const struct asn1_cursor *certificate,
struct x509_rsa_public_key *rsa_pubkey ) {
struct asn1_cursor algorithm;
struct asn1_cursor pubkey;
struct asn1_cursor modulus;
struct asn1_cursor exponent;
int rc;
/* First, extract the public key algorithm and key data */
if ( ( rc = x509_public_key ( certificate, &algorithm,
&pubkey ) ) != 0 )
return rc;
/* Check that algorithm is RSA */
rc = ( asn1_enter ( &algorithm, ASN1_OID ) /* algorithm */ );
if ( rc != 0 ) {
DBG ( "Cannot locate algorithm:\n" );
DBG_HDA ( 0, certificate->data, certificate->len );
return rc;
}
if ( ( algorithm.len != sizeof ( oid_rsa_encryption ) ) ||
( memcmp ( algorithm.data, &oid_rsa_encryption,
sizeof ( oid_rsa_encryption ) ) != 0 ) ) {
DBG ( "algorithm is not rsaEncryption in:\n" );
DBG_HDA ( 0, certificate->data, certificate->len );
return -ENOTSUP;
}
/* Check that public key is a byte string, i.e. that the
* "unused bits" byte contains zero.
*/
if ( ( pubkey.len < 1 ) ||
( ( *( uint8_t * ) pubkey.data ) != 0 ) ) {
DBG ( "subjectPublicKey is not a byte string in:\n" );
DBG_HDA ( 0, certificate->data, certificate->len );
return -ENOTSUP;
}
pubkey.data++;
pubkey.len--;
/* Pick out the modulus and exponent */
rc = ( asn1_enter ( &pubkey, ASN1_SEQUENCE ) /* RSAPublicKey */ );
if ( rc != 0 ) {
DBG ( "Cannot locate RSAPublicKey in:\n" );
DBG_HDA ( 0, certificate->data, certificate->len );
return -ENOTSUP;
}
memcpy ( &modulus, &pubkey, sizeof ( modulus ) );
rc = ( asn1_enter ( &modulus, ASN1_INTEGER ) /* modulus */ );
if ( rc != 0 ) {
DBG ( "Cannot locate modulus in:\n" );
DBG_HDA ( 0, certificate->data, certificate->len );
return -ENOTSUP;
}
memcpy ( &exponent, &pubkey, sizeof ( exponent ) );
rc = ( asn1_skip ( &exponent, ASN1_INTEGER ), /* modulus */
asn1_enter ( &exponent, ASN1_INTEGER ) /* publicExponent */ );
if ( rc != 0 ) {
DBG ( "Cannot locate publicExponent in:\n" );
DBG_HDA ( 0, certificate->data, certificate->len );
return -ENOTSUP;
}
/* Allocate space and copy out modulus and exponent */
rsa_pubkey->modulus = malloc ( modulus.len + exponent.len );
if ( ! rsa_pubkey->modulus )
return -ENOMEM;
rsa_pubkey->exponent = ( rsa_pubkey->modulus + modulus.len );
memcpy ( rsa_pubkey->modulus, modulus.data, modulus.len );
rsa_pubkey->modulus_len = modulus.len;
memcpy ( rsa_pubkey->exponent, exponent.data, exponent.len );
rsa_pubkey->exponent_len = exponent.len;
DBG2 ( "RSA modulus:\n" );
DBG2_HDA ( 0, rsa_pubkey->modulus, rsa_pubkey->modulus_len );
DBG2 ( "RSA exponent:\n" );
DBG2_HDA ( 0, rsa_pubkey->exponent, rsa_pubkey->exponent_len );
return 0;
}
|
