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
|
/*
Copyright (C) 2013 Carl Hetherington <cth@carlh.net>
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.
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.
*/
#include <iomanip>
#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <libcxml/cxml.h>
#include "KM_util.h"
#include "kdm.h"
#include "exceptions.h"
using std::list;
using std::string;
using std::stringstream;
using std::hex;
using std::setw;
using std::setfill;
using boost::shared_ptr;
using namespace libdcp;
KDM::KDM (boost::filesystem::path kdm, boost::filesystem::path private_key)
{
/* Read the private key */
FILE* private_key_file = fopen (private_key.string().c_str(), "r");
if (!private_key_file) {
throw FileError ("could not find RSA private key file", private_key.string ());
}
RSA* rsa = PEM_read_RSAPrivateKey (private_key_file, 0, 0, 0);
fclose (private_key_file);
if (!rsa) {
throw FileError ("could not read RSA private key file", private_key.string ());
}
/* Read the KDM, decrypting it */
cxml::File f (kdm.string (), "DCinemaSecurityMessage");
shared_ptr<cxml::Node> authenticated_private = f.node_child ("AuthenticatedPrivate");
list<shared_ptr<cxml::Node> > encrypted_keys = authenticated_private->node_children ("EncryptedKey");
for (list<shared_ptr<cxml::Node> >::iterator i = encrypted_keys.begin(); i != encrypted_keys.end(); ++i) {
/* Get the base-64-encoded cipher value from the KDM */
shared_ptr<cxml::Node> cipher_data = (*i)->node_child ("CipherData");
shared_ptr<cxml::Node> cipher_value_base64 = cipher_data->node_child ("CipherValue");
/* Decode it from base-64 */
unsigned char cipher_value[256];
ui32_t cipher_value_len;
if (Kumu::base64decode (cipher_value_base64->content().c_str(), cipher_value, sizeof (cipher_value), &cipher_value_len)) {
RSA_free (rsa);
throw MiscError ("could not base-64-decode CipherValue from KDM");
}
/* Decrypt it */
unsigned char decrypted[256];
unsigned int const decrypted_len = RSA_private_decrypt (cipher_value_len, cipher_value, decrypted, rsa, RSA_PKCS1_OAEP_PADDING);
assert (decrypted_len < sizeof (decrypted));
_ciphers.push_back (KDMCipher (decrypted, decrypted_len));
}
RSA_free (rsa);
}
KDMCipher::KDMCipher (unsigned char const * raw, int len)
{
switch (len) {
case 134:
/* interop */
_structure_id = get (&raw, 16);
_signer_thumbprint = get (&raw, 20);
_cpl_id = get_uuid (&raw, 16);
_key_id = get_uuid (&raw, 16);
_not_valid_before = get (&raw, 25);
_not_valid_after = get (&raw, 25);
memcpy (_key_raw, raw, 16);
_key_string = get_hex (&raw, 16);
break;
case 138:
/* SMPTE */
_structure_id = get (&raw, 16);
_signer_thumbprint = get (&raw, 20);
_cpl_id = get_uuid (&raw, 16);
_key_type = get (&raw, 4);
_key_id = get_uuid (&raw, 16);
_not_valid_before = get (&raw, 25);
_not_valid_after = get (&raw, 25);
memcpy (_key_raw, raw, 16);
_key_string = get_hex (&raw, 16);
break;
default:
assert (false);
}
}
string
KDMCipher::get (unsigned char const ** p, int N) const
{
string g;
for (int i = 0; i < N; ++i) {
g += **p;
(*p)++;
}
return g;
}
string
KDMCipher::get_uuid (unsigned char const ** p, int N) const
{
stringstream g;
for (int i = 0; i < N; ++i) {
g << setw(2) << setfill('0') << hex << static_cast<int> (**p);
(*p)++;
if (i == 3 || i == 5 || i == 7 || i == 9) {
g << '-';
}
}
return g.str ();
}
string
KDMCipher::get_hex (unsigned char const ** p, int N) const
{
stringstream g;
for (int i = 0; i < N; ++i) {
g << setw(2) << setfill('0') << hex << static_cast<int> (**p);
(*p)++;
}
return g.str ();
}
|
