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
184
185
186
|
/*
* Copyright (C) 2009 Martin Willi
* Hochschule fuer Technik Rapperswil
*
* 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 (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* 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.
*/
#include "dnskey_builder.h"
#include <debug.h>
#include <credentials/keys/private_key.h>
typedef struct dnskey_rr_t dnskey_rr_t;
typedef enum dnskey_algorithm_t dnskey_algorithm_t;
/**
* Header of a DNSKEY resource record
*/
struct dnskey_rr_t {
u_int16_t flags;
u_int8_t protocol;
u_int8_t algorithm;
u_int8_t data[];
} __attribute__((__packed__));
/**
* DNSSEC algorithms, RFC4034 Appendix A.1.
*/
enum dnskey_algorithm_t {
DNSKEY_ALG_RSA_MD5 = 1,
DNSKEY_ALG_DH = 2,
DNSKEY_ALG_DSA = 3,
DNSKEY_ALG_ECC = 4,
DNSKEY_ALG_RSA_SHA1 = 5,
};
/**
* Load a generic public key from a DNSKEY RR blob
*/
static public_key_t *parse_public_key(chunk_t blob)
{
dnskey_rr_t *rr = (dnskey_rr_t*)blob.ptr;
if (blob.len < sizeof(dnskey_rr_t))
{
DBG1("DNSKEY too short");
return NULL;
}
blob = chunk_skip(blob, sizeof(dnskey_rr_t));
switch (rr->algorithm)
{
case DNSKEY_ALG_RSA_SHA1:
return lib->creds->create(lib->creds, CRED_PUBLIC_KEY, KEY_RSA,
BUILD_BLOB_DNSKEY, blob, BUILD_END);
default:
DBG1("DNSKEY public key algorithm %d not supported", rr->algorithm);
return NULL;
}
}
/**
* Load a RSA public key from DNSKEY RR data
*/
static public_key_t *parse_rsa_public_key(chunk_t blob)
{
chunk_t n, e;
if (blob.len < 3)
{
DBG1("RFC 3110 public key blob too short for exponent length");
return NULL;
}
if (blob.ptr[0])
{
e.len = blob.ptr[0];
blob = chunk_skip(blob, 1);
}
else
{
e.len = blob.ptr[1] * 256 + blob.ptr[2];
blob = chunk_skip(blob, 3);
}
e.ptr = blob.ptr;
if (e.len >= blob.len)
{
DBG1("RFC 3110 public key blob too short for exponent");
return NULL;
}
n = chunk_skip(blob, e.len);
return lib->creds->create(lib->creds, CRED_PUBLIC_KEY, KEY_RSA,
BUILD_RSA_MODULUS, n, BUILD_RSA_PUB_EXP, e,
BUILD_END);
}
typedef struct private_builder_t private_builder_t;
/**
* Builder implementation for private/public key loading
*/
struct private_builder_t {
/** implements the builder interface */
builder_t public;
/** dnskey packet data */
chunk_t blob;
/** type of key to build */
key_type_t type;
};
/**
* Implementation of builder_t.build for public keys
*/
static public_key_t *build_public(private_builder_t *this)
{
public_key_t *key = NULL;
switch (this->type)
{
case KEY_ANY:
key = parse_public_key(this->blob);
break;
case KEY_RSA:
key = parse_rsa_public_key(this->blob);
break;
default:
break;
}
free(this);
return key;
}
/**
* Implementation of builder_t.add for public keys
*/
static void add_public(private_builder_t *this, builder_part_t part, ...)
{
va_list args;
switch (part)
{
case BUILD_BLOB_DNSKEY:
{
va_start(args, part);
this->blob = va_arg(args, chunk_t);
va_end(args);
break;
}
default:
builder_cancel(&this->public);
break;
}
}
/**
* Builder construction function for public keys
*/
builder_t *dnskey_public_key_builder(key_type_t type)
{
private_builder_t *this;
if (type != KEY_ANY && type != KEY_RSA)
{
return NULL;
}
this = malloc_thing(private_builder_t);
this->blob = chunk_empty;
this->type = type;
this->public.add = (void(*)(builder_t *this, builder_part_t part, ...))add_public;
this->public.build = (void*(*)(builder_t *this))build_public;
return &this->public;
}
|
