/*

 * ima-evm-utils - IMA/EVM support utilities

 *

 * Copyright (C) 2011 Nokia Corporation

 * Copyright (C) 2011,2012,2013 Intel Corporation

 * Copyright (C) 2013,2014 Samsung Electronics

 *

 * Authors:

 * Dmitry Kasatkin <dmitry.kasatkin@nokia.com>

 *                 <dmitry.kasatkin@intel.com>

 *                 <d.kasatkin@samsung.com>

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * version 2 as published by the Free Software Foundation.

 *

 * 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, see <http://www.gnu.org/licenses/>.

 *

 * As a special exception, the copyright holders give permission to link the

 * code of portions of this program with the OpenSSL library under certain

 * conditions as described in each individual source file and distribute

 * linked combinations including the program with the OpenSSL library. You

 * must comply with the GNU General Public License in all respects

 * for all of the code used other than as permitted herein. If you modify

 * file(s) with this exception, you may extend this exception to your

 * version of the file(s), but you are not obligated to do so. If you do not

 * wish to do so, delete this exception statement from your version. If you

 * delete this exception statement from all source files in the program,

 * then also delete it in the license file.

 *

 * File: pcr_tsspcrread.c

 *	 PCR reading implementation based on IBM TSS2

 */

#include <errno.h>

#include <limits.h>

#include <stdio.h>

#include <string.h>

#include <stdint.h>

#include <openssl/sha.h>

#define USE_FPRINTF

#include "utils.h"

#include "imaevm.h"

#define CMD "tsspcrread"

static char path[PATH_MAX];

int tpm2_pcr_supported(void)

{

	if (imaevm_params.verbose > LOG_INFO)

		log_info("Using %s to read PCRs.\n", CMD);

	if (get_cmd_path(CMD, path, sizeof(path))) {

		log_debug("Couldn't find '%s' in $PATH", CMD);

		return 0;

	}

	log_debug("Found '%s' in $PATH", CMD);

	return 1;

}

int tpm2_pcr_read(const char *algo_name, int idx, uint8_t *hwpcr,

		 int len, char **errmsg)

{

	FILE *fp;

	char pcr[100];	/* may contain an error */

	char cmd[PATH_MAX + 50];

	int ret;

	sprintf(cmd, "%s -halg %s -ha %d -ns 2> /dev/null",

		path, algo_name, idx);

	fp = popen(cmd, "r");

	if (!fp) {

		ret = asprintf(errmsg, "popen failed: %s", strerror(errno));

		if (ret == -1)	/* the contents of errmsg is undefined */

			*errmsg = NULL;

		return -1;

	}

	if (fgets(pcr, sizeof(pcr), fp) == NULL) {

		ret = asprintf(errmsg, "tsspcrread failed: %s",

			       strerror(errno));

		if (ret == -1)	/* the contents of errmsg is undefined */

			*errmsg = NULL;

		ret = pclose(fp);

		return -1;

	}

	/* get the popen "cmd" return code */

	ret = pclose(fp);

	/* Treat an unallocated bank as an error */

	if (!ret && (strlen(pcr) < SHA_DIGEST_LENGTH))

		ret = -1;

	if (!ret)

		hex2bin(hwpcr, pcr, len);

	else

		*errmsg = strndup(pcr, strlen(pcr) - 1); /* remove newline */

	return ret;

}