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/*
* 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/tcg_pts_attr_proto_caps.h>
#include <tcg/tcg_pts_attr_meas_algo.h>
#include <tcg/tcg_pts_attr_dh_nonce_params_req.h>
#include <tcg/tcg_pts_attr_dh_nonce_finish.h>
#include <tcg/tcg_pts_attr_get_tpm_version_info.h>
#include <tcg/tcg_pts_attr_get_aik.h>
#include <tcg/tcg_pts_attr_req_func_comp_evid.h>
#include <tcg/tcg_pts_attr_gen_attest_evid.h>
#include <tcg/tcg_pts_attr_req_file_meas.h>
#include <tcg/tcg_pts_attr_req_file_meta.h>
#include <utils/debug.h>
bool imv_attestation_build(imv_msg_t *out_msg,
imv_attestation_state_t *attestation_state,
pts_meas_algorithms_t supported_algorithms,
pts_dh_group_t supported_dh_groups,
pts_database_t *pts_db)
{
imv_attestation_handshake_state_t handshake_state;
pts_t *pts;
pa_tnc_attr_t *attr = NULL;
handshake_state = attestation_state->get_handshake_state(attestation_state);
pts = attestation_state->get_pts(attestation_state);
/**
* 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 - "
"advancing to TPM Initialization");
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 - "
"advancing to File Measurements");
handshake_state = IMV_ATTESTATION_STATE_MEAS;
}
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_NONCE_REQ);
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_MEAS);
break;
}
case IMV_ATTESTATION_STATE_MEAS:
{
enumerator_t *enumerator;
u_int32_t delimiter = SOLIDUS_UTF;
char *platform_info, *pathname;
u_int16_t request_id;
int id, type;
bool is_dir, have_request = FALSE;
attestation_state->set_handshake_state(attestation_state,
IMV_ATTESTATION_STATE_COMP_EVID);
/* Get Platform and OS of the PTS-IMC */
platform_info = pts->get_platform_info(pts);
if (!pts_db || !platform_info)
{
DBG1(DBG_IMV, "%s%s%s not available",
(pts_db) ? "" : "pts database",
(!pts_db && !platform_info) ? "and" : "",
(platform_info) ? "" : "platform info");
break;
}
DBG1(DBG_IMV, "platform is '%s'", platform_info);
/* Send Request File Metadata attribute */
enumerator = pts_db->create_file_meta_enumerator(pts_db,
platform_info);
if (!enumerator)
{
break;
}
while (enumerator->enumerate(enumerator, &type, &pathname))
{
is_dir = (type != 0);
DBG2(DBG_IMV, "metadata request for %s '%s'",
is_dir ? "directory" : "file", pathname);
attr = tcg_pts_attr_req_file_meta_create(is_dir, delimiter,
pathname);
attr->set_noskip_flag(attr, TRUE);
out_msg->add_attribute(out_msg, attr);
have_request = TRUE;
}
enumerator->destroy(enumerator);
/* Send Request File Measurement attribute */
enumerator = pts_db->create_file_meas_enumerator(pts_db,
platform_info);
if (!enumerator)
{
break;
}
while (enumerator->enumerate(enumerator, &id, &type, &pathname))
{
is_dir = (type != 0);
request_id = attestation_state->add_file_meas_request(
attestation_state, id, is_dir);
DBG2(DBG_IMV, "measurement request %d for %s '%s'",
request_id, is_dir ? "directory" : "file", pathname);
attr = tcg_pts_attr_req_file_meas_create(is_dir, request_id,
delimiter, pathname);
attr->set_noskip_flag(attr, TRUE);
out_msg->add_attribute(out_msg, attr);
have_request = TRUE;
}
enumerator->destroy(enumerator);
/* do we have any file metadata or measurement requests? */
if (have_request)
{
break;
}
/* fall through to next state */
}
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:
break;
}
return TRUE;
}
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