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
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
|
/*
* Copyright (C) 2011-2012 Sansar Choinyambuu, Andreas Steffen
* HSR 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 "imv_attestation_build.h"
#include "imv_attestation_state.h"
#include <tcg/pts/tcg_pts_attr_proto_caps.h>
#include <tcg/pts/tcg_pts_attr_meas_algo.h>
#include <tcg/pts/tcg_pts_attr_dh_nonce_params_req.h>
#include <tcg/pts/tcg_pts_attr_dh_nonce_finish.h>
#include <tcg/pts/tcg_pts_attr_get_tpm_version_info.h>
#include <tcg/pts/tcg_pts_attr_get_aik.h>
#include <tcg/pts/tcg_pts_attr_req_func_comp_evid.h>
#include <tcg/pts/tcg_pts_attr_gen_attest_evid.h>
#include <utils/debug.h>
bool imv_attestation_build(imv_msg_t *out_msg,
imv_state_t *state,
pts_meas_algorithms_t supported_algorithms,
pts_dh_group_t supported_dh_groups,
pts_database_t *pts_db)
{
imv_attestation_state_t *attestation_state;
imv_attestation_handshake_state_t handshake_state;
pts_t *pts;
pa_tnc_attr_t *attr = NULL;
attestation_state = (imv_attestation_state_t*)state;
handshake_state = attestation_state->get_handshake_state(attestation_state);
pts = attestation_state->get_pts(attestation_state);
/**
* Received a response form the Attestation IMC so we can proceeed
*/
if (handshake_state == IMV_ATTESTATION_STATE_DISCOVERY &&
(state->get_action_flags(state) & IMV_ATTESTATION_FLAG_ALGO))
{
handshake_state = IMV_ATTESTATION_STATE_NONCE_REQ;
}
/**
* Skip DH Nonce Parameters Request attribute when
* DH Nonce Exchange is not selected by PTS-IMC side
*/
if (handshake_state == IMV_ATTESTATION_STATE_NONCE_REQ &&
!(pts->get_proto_caps(pts) & PTS_PROTO_CAPS_D))
{
DBG2(DBG_IMV, "PTS-IMC does not support DH Nonce negotiation");
handshake_state = IMV_ATTESTATION_STATE_TPM_INIT;
}
/**
* Skip TPM Version Info and AIK attributes when
* no TPM is available on the PTS-IMC side
*/
if (handshake_state == IMV_ATTESTATION_STATE_TPM_INIT &&
!(pts->get_proto_caps(pts) & PTS_PROTO_CAPS_T))
{
DBG2(DBG_IMV, "PTS-IMC made no TPM available");
handshake_state = IMV_ATTESTATION_STATE_END;
}
switch (handshake_state)
{
case IMV_ATTESTATION_STATE_INIT:
{
pts_proto_caps_flag_t flags;
/* Send Request Protocol Capabilities attribute */
flags = pts->get_proto_caps(pts);
attr = tcg_pts_attr_proto_caps_create(flags, TRUE);
attr->set_noskip_flag(attr, TRUE);
out_msg->add_attribute(out_msg, attr);
/* Send Measurement Algorithms attribute */
attr = tcg_pts_attr_meas_algo_create(supported_algorithms, FALSE);
attr->set_noskip_flag(attr, TRUE);
out_msg->add_attribute(out_msg, attr);
attestation_state->set_handshake_state(attestation_state,
IMV_ATTESTATION_STATE_DISCOVERY);
break;
}
case IMV_ATTESTATION_STATE_DISCOVERY:
break;
case IMV_ATTESTATION_STATE_NONCE_REQ:
{
int min_nonce_len;
/* Send DH nonce parameters request attribute */
min_nonce_len = lib->settings->get_int(lib->settings,
"libimcv.plugins.imv-attestation.min_nonce_len", 0);
attr = tcg_pts_attr_dh_nonce_params_req_create(min_nonce_len,
supported_dh_groups);
attr->set_noskip_flag(attr, TRUE);
out_msg->add_attribute(out_msg, attr);
attestation_state->set_handshake_state(attestation_state,
IMV_ATTESTATION_STATE_TPM_INIT);
break;
}
case IMV_ATTESTATION_STATE_TPM_INIT:
{
pts_meas_algorithms_t selected_algorithm;
chunk_t initiator_value, initiator_nonce;
if ((pts->get_proto_caps(pts) & PTS_PROTO_CAPS_D))
{
/* Send DH nonce finish attribute */
selected_algorithm = pts->get_meas_algorithm(pts);
pts->get_my_public_value(pts, &initiator_value, &initiator_nonce);
attr = tcg_pts_attr_dh_nonce_finish_create(selected_algorithm,
initiator_value, initiator_nonce);
attr->set_noskip_flag(attr, TRUE);
out_msg->add_attribute(out_msg, attr);
}
/* Send Get TPM Version attribute */
attr = tcg_pts_attr_get_tpm_version_info_create();
attr->set_noskip_flag(attr, TRUE);
out_msg->add_attribute(out_msg, attr);
/* Send Get AIK attribute */
attr = tcg_pts_attr_get_aik_create();
attr->set_noskip_flag(attr, TRUE);
out_msg->add_attribute(out_msg, attr);
attestation_state->set_handshake_state(attestation_state,
IMV_ATTESTATION_STATE_COMP_EVID);
break;
}
case IMV_ATTESTATION_STATE_COMP_EVID:
{
tcg_pts_attr_req_func_comp_evid_t *attr_cast;
enumerator_t *enumerator;
pts_component_t *comp;
pts_comp_func_name_t *comp_name;
chunk_t keyid;
int kid, vid, name, qualifier;
u_int8_t flags;
u_int32_t depth;
bool first = TRUE, first_component = TRUE;
attestation_state->set_handshake_state(attestation_state,
IMV_ATTESTATION_STATE_END);
if (!(pts->get_proto_caps(pts) & PTS_PROTO_CAPS_T) ||
!(pts->get_proto_caps(pts) & PTS_PROTO_CAPS_D))
{
DBG2(DBG_IMV, "PTS-IMC made no TPM available - "
"skipping Component Measurements");
break;
}
if (!pts->get_aik_keyid(pts, &keyid))
{
DBG1(DBG_IMV, "retrieval of AIK keyid failed");
return FALSE;
}
if (!pts_db)
{
DBG1(DBG_IMV, "pts database not available");
break;
}
if (pts_db->check_aik_keyid(pts_db, keyid, &kid) != SUCCESS)
{
return FALSE;
}
enumerator = pts_db->create_comp_evid_enumerator(pts_db, kid);
if (!enumerator)
{
break;
}
while (enumerator->enumerate(enumerator, &vid, &name,
&qualifier, &depth))
{
if (first)
{
DBG2(DBG_IMV, "evidence request by");
first = FALSE;
}
comp_name = pts_comp_func_name_create(vid, name, qualifier);
comp_name->log(comp_name, " ");
comp = attestation_state->create_component(attestation_state,
comp_name, depth, pts_db);
if (!comp)
{
DBG2(DBG_IMV, " not registered or duplicate"
" - removed from request");
comp_name->destroy(comp_name);
continue;
}
if (first_component)
{
attr = tcg_pts_attr_req_func_comp_evid_create();
attr->set_noskip_flag(attr, TRUE);
first_component = FALSE;
}
flags = comp->get_evidence_flags(comp);
/* TODO check flags against negotiated_caps */
attr_cast = (tcg_pts_attr_req_func_comp_evid_t *)attr;
attr_cast->add_component(attr_cast, flags, depth, comp_name);
}
enumerator->destroy(enumerator);
if (attr)
{
/* Send Request Functional Component Evidence attribute */
out_msg->add_attribute(out_msg, attr);
/* Send Generate Attestation Evidence attribute */
attr = tcg_pts_attr_gen_attest_evid_create();
attr->set_noskip_flag(attr, TRUE);
out_msg->add_attribute(out_msg, attr);
attestation_state->set_handshake_state(attestation_state,
IMV_ATTESTATION_STATE_EVID_FINAL);
}
break;
}
case IMV_ATTESTATION_STATE_EVID_FINAL:
if (attestation_state->components_finalized(attestation_state))
{
attestation_state->set_handshake_state(attestation_state,
IMV_ATTESTATION_STATE_END);
}
break;
case IMV_ATTESTATION_STATE_END:
attestation_state->set_handshake_state(attestation_state,
IMV_ATTESTATION_STATE_END);
break;
}
return TRUE;
}
|
