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/* $OpenBSD: scard.c,v 1.36 2006/11/06 21:25:28 markus Exp $ */

/*

 * Copyright (c) 2001 Markus Friedl.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include "includes.h"

#if defined(SMARTCARD) && defined(USE_SECTOK)

#include <sys/types.h>

#include <sectok.h>

#include <stdarg.h>

#include <string.h>

#include <openssl/evp.h>

#include "xmalloc.h"

#include "key.h"

#include "log.h"

#include "misc.h"

#include "scard.h"

#if OPENSSL_VERSION_NUMBER < 0x00907000L

#define USE_ENGINE

#define RSA_get_default_method RSA_get_default_openssl_method

#else

#endif

#ifdef USE_ENGINE

#include <openssl/engine.h>

#define sc_get_rsa sc_get_engine

#else

#define sc_get_rsa sc_get_rsa_method

#endif

#define CLA_SSH 0x05

#define INS_DECRYPT 0x10

#define INS_GET_KEYLENGTH 0x20

#define INS_GET_PUBKEY 0x30

#define INS_GET_RESPONSE 0xc0

#define MAX_BUF_SIZE 256

u_char DEFAUT0[] = {0xad, 0x9f, 0x61, 0xfe, 0xfa, 0x20, 0xce, 0x63};

static int sc_fd = -1;

static char *sc_reader_id = NULL;

static char *sc_pin = NULL;

static int cla = 0x00;	/* class */

static void sc_mk_digest(const char *pin, u_char *digest);

static int get_AUT0(u_char *aut0);

static int try_AUT0(void);

/* interface to libsectok */

static int

sc_open(void)

{

	int sw;

	if (sc_fd >= 0)

		return sc_fd;

	sc_fd = sectok_friendly_open(sc_reader_id, STONOWAIT, &sw);

	if (sc_fd < 0) {

		error("sectok_open failed: %s", sectok_get_sw(sw));

		return SCARD_ERROR_FAIL;

	}

	if (! sectok_cardpresent(sc_fd)) {

		debug("smartcard in reader %s not present, skipping",

		    sc_reader_id);

		sc_close();

		return SCARD_ERROR_NOCARD;

	}

	if (sectok_reset(sc_fd, 0, NULL, &sw) <= 0) {

		error("sectok_reset failed: %s", sectok_get_sw(sw));

		sc_fd = -1;

		return SCARD_ERROR_FAIL;

	}

	if ((cla = cyberflex_inq_class(sc_fd)) < 0)

		cla = 0;

	debug("sc_open ok %d", sc_fd);

	return sc_fd;

}

static int

sc_enable_applet(void)

{

	static u_char aid[] = {0xfc, 0x53, 0x73, 0x68, 0x2e, 0x62, 0x69, 0x6e};

	int sw = 0;

	/* select applet id */

	sectok_apdu(sc_fd, cla, 0xa4, 0x04, 0, sizeof aid, aid, 0, NULL, &sw);

	if (!sectok_swOK(sw)) {

		error("sectok_apdu failed: %s", sectok_get_sw(sw));

		sc_close();

		return -1;

	}

	return 0;

}

static int

sc_init(void)

{

	int status;

	status = sc_open();

	if (status == SCARD_ERROR_NOCARD) {

		return SCARD_ERROR_NOCARD;

	}

	if (status < 0) {

		error("sc_open failed");

		return status;

	}

	if (sc_enable_applet() < 0) {

		error("sc_enable_applet failed");

		return SCARD_ERROR_APPLET;

	}

	return 0;

}

static int

sc_read_pubkey(Key * k)

{

	u_char buf[2], *n;

	char *p;

	int len, sw, status = -1;

	len = sw = 0;

	n = NULL;

	if (sc_fd < 0) {

		if (sc_init() < 0)

			goto err;

	}

	/* get key size */

	sectok_apdu(sc_fd, CLA_SSH, INS_GET_KEYLENGTH, 0, 0, 0, NULL,

	    sizeof(buf), buf, &sw);

	if (!sectok_swOK(sw)) {

		error("could not obtain key length: %s", sectok_get_sw(sw));

		goto err;

	}

	len = (buf[0] << 8) | buf[1];

	len /= 8;

	debug("INS_GET_KEYLENGTH: len %d sw %s", len, sectok_get_sw(sw));

	n = xmalloc(len);

	/* get n */

	sectok_apdu(sc_fd, CLA_SSH, INS_GET_PUBKEY, 0, 0, 0, NULL, len, n, &sw);

	if (sw == 0x6982) {

		if (try_AUT0() < 0)

			goto err;

		sectok_apdu(sc_fd, CLA_SSH, INS_GET_PUBKEY, 0, 0, 0, NULL, len, n, &sw);

	}

	if (!sectok_swOK(sw)) {

		error("could not obtain public key: %s", sectok_get_sw(sw));

		goto err;

	}

	debug("INS_GET_KEYLENGTH: sw %s", sectok_get_sw(sw));

	if (BN_bin2bn(n, len, k->rsa->n) == NULL) {

		error("c_read_pubkey: BN_bin2bn failed");

		goto err;

	}

	/* currently the java applet just stores 'n' */

	if (!BN_set_word(k->rsa->e, 35)) {

		error("c_read_pubkey: BN_set_word(e, 35) failed");

		goto err;

	}

	status = 0;

	p = key_fingerprint(k, SSH_FP_MD5, SSH_FP_HEX);

	debug("fingerprint %u %s", key_size(k), p);

	xfree(p);

err:

	if (n != NULL)

		xfree(n);

	sc_close();

	return status;

}

/* private key operations */

static int

sc_private_decrypt(int flen, u_char *from, u_char *to, RSA *rsa,

    int padding)

{

	u_char *padded = NULL;

	int sw, len, olen, status = -1;

	debug("sc_private_decrypt called");

	olen = len = sw = 0;

	if (sc_fd < 0) {

		status = sc_init();

		if (status < 0)

			goto err;

	}

	if (padding != RSA_PKCS1_PADDING)

		goto err;

	len = BN_num_bytes(rsa->n);

	padded = xmalloc(len);

	sectok_apdu(sc_fd, CLA_SSH, INS_DECRYPT, 0, 0, len, from, len, padded, &sw);

	if (sw == 0x6982) {

		if (try_AUT0() < 0)

			goto err;

		sectok_apdu(sc_fd, CLA_SSH, INS_DECRYPT, 0, 0, len, from, len, padded, &sw);

	}

	if (!sectok_swOK(sw)) {

		error("sc_private_decrypt: INS_DECRYPT failed: %s",

		    sectok_get_sw(sw));

		goto err;

	}

	olen = RSA_padding_check_PKCS1_type_2(to, len, padded + 1, len - 1,

	    len);

err:

	if (padded)

		xfree(padded);

	sc_close();

	return (olen >= 0 ? olen : status);

}

static int

sc_private_encrypt(int flen, u_char *from, u_char *to, RSA *rsa,

    int padding)

{

	u_char *padded = NULL;

	int sw, len, status = -1;

	len = sw = 0;

	if (sc_fd < 0) {

		status = sc_init();

		if (status < 0)

			goto err;

	}

	if (padding != RSA_PKCS1_PADDING)

		goto err;

	debug("sc_private_encrypt called");

	len = BN_num_bytes(rsa->n);

	padded = xmalloc(len);

	if (RSA_padding_add_PKCS1_type_1(padded, len, (u_char *)from, flen) <= 0) {

		error("RSA_padding_add_PKCS1_type_1 failed");

		goto err;

	}

	sectok_apdu(sc_fd, CLA_SSH, INS_DECRYPT, 0, 0, len, padded, len, to, &sw);

	if (sw == 0x6982) {

		if (try_AUT0() < 0)

			goto err;

		sectok_apdu(sc_fd, CLA_SSH, INS_DECRYPT, 0, 0, len, padded, len, to, &sw);

	}

	if (!sectok_swOK(sw)) {

		error("sc_private_encrypt: INS_DECRYPT failed: %s",

		    sectok_get_sw(sw));

		goto err;

	}

err:

	if (padded)

		xfree(padded);

	sc_close();

	return (len >= 0 ? len : status);

}

/* called on free */

static int (*orig_finish)(RSA *rsa) = NULL;

static int

sc_finish(RSA *rsa)

{

	if (orig_finish)

		orig_finish(rsa);

	sc_close();

	return 1;

}

/* engine for overloading private key operations */

static RSA_METHOD *

sc_get_rsa_method(void)

{

	static RSA_METHOD smart_rsa;

	const RSA_METHOD *def = RSA_get_default_method();

	/* use the OpenSSL version */

	memcpy(&smart_rsa, def, sizeof(smart_rsa));

	smart_rsa.name		= "sectok";

	/* overload */

	smart_rsa.rsa_priv_enc	= sc_private_encrypt;

	smart_rsa.rsa_priv_dec	= sc_private_decrypt;

	/* save original */

	orig_finish		= def->finish;

	smart_rsa.finish	= sc_finish;

	return &smart_rsa;

}

#ifdef USE_ENGINE

static ENGINE *

sc_get_engine(void)

{

	static ENGINE *smart_engine = NULL;

	if ((smart_engine = ENGINE_new()) == NULL)

		fatal("ENGINE_new failed");

	ENGINE_set_id(smart_engine, "sectok");

	ENGINE_set_name(smart_engine, "libsectok");

	ENGINE_set_RSA(smart_engine, sc_get_rsa_method());

	ENGINE_set_DSA(smart_engine, DSA_get_default_openssl_method());

	ENGINE_set_DH(smart_engine, DH_get_default_openssl_method());

	ENGINE_set_RAND(smart_engine, RAND_SSLeay());

	ENGINE_set_BN_mod_exp(smart_engine, BN_mod_exp);

	return smart_engine;

}

#endif

void

sc_close(void)

{

	if (sc_fd >= 0) {

		sectok_close(sc_fd);

		sc_fd = -1;

	}

}

Key **

sc_get_keys(const char *id, const char *pin)

{

	Key *k, *n, **keys;

	int status, nkeys = 2;

	if (sc_reader_id != NULL)

		xfree(sc_reader_id);

	sc_reader_id = xstrdup(id);

	if (sc_pin != NULL)

		xfree(sc_pin);

	sc_pin = (pin == NULL) ? NULL : xstrdup(pin);

	k = key_new(KEY_RSA);

	if (k == NULL) {

		return NULL;

	}

	status = sc_read_pubkey(k);

	if (status == SCARD_ERROR_NOCARD) {

		key_free(k);

		return NULL;

	}

	if (status < 0) {

		error("sc_read_pubkey failed");

		key_free(k);

		return NULL;

	}

	keys = xcalloc((nkeys+1), sizeof(Key *));

	n = key_new(KEY_RSA1);

	if ((BN_copy(n->rsa->n, k->rsa->n) == NULL) ||

	    (BN_copy(n->rsa->e, k->rsa->e) == NULL))

		fatal("sc_get_keys: BN_copy failed");

	RSA_set_method(n->rsa, sc_get_rsa());

	n->flags |= KEY_FLAG_EXT;

	keys[0] = n;

	n = key_new(KEY_RSA);

	if ((BN_copy(n->rsa->n, k->rsa->n) == NULL) ||

	    (BN_copy(n->rsa->e, k->rsa->e) == NULL))

		fatal("sc_get_keys: BN_copy failed");

	RSA_set_method(n->rsa, sc_get_rsa());

	n->flags |= KEY_FLAG_EXT;

	keys[1] = n;

	keys[2] = NULL;

	key_free(k);

	return keys;

}

#define NUM_RSA_KEY_ELEMENTS 5+1

#define COPY_RSA_KEY(x, i) \

	do { \

		len = BN_num_bytes(prv->rsa->x); \

		elements[i] = xmalloc(len); \

		debug("#bytes %d", len); \

		if (BN_bn2bin(prv->rsa->x, elements[i]) < 0) \

			goto done; \

	} while (0)

static void

sc_mk_digest(const char *pin, u_char *digest)

{

	const EVP_MD *evp_md = EVP_sha1();

	EVP_MD_CTX md;

	EVP_DigestInit(&md, evp_md);

	EVP_DigestUpdate(&md, pin, strlen(pin));

	EVP_DigestFinal(&md, digest, NULL);

}

static int

get_AUT0(u_char *aut0)

{

	char *pass;

	pass = read_passphrase("Enter passphrase for smartcard: ", RP_ALLOW_STDIN);

	if (pass == NULL)

		return -1;

	if (!strcmp(pass, "-")) {

		memcpy(aut0, DEFAUT0, sizeof DEFAUT0);

		return 0;

	}

	sc_mk_digest(pass, aut0);

	memset(pass, 0, strlen(pass));

	xfree(pass);

	return 0;

}

static int

try_AUT0(void)

{

	u_char aut0[EVP_MAX_MD_SIZE];

	/* permission denied; try PIN if provided */

	if (sc_pin && strlen(sc_pin) > 0) {

		sc_mk_digest(sc_pin, aut0);

		if (cyberflex_verify_AUT0(sc_fd, cla, aut0, 8) < 0) {

			error("smartcard passphrase incorrect");

			return (-1);

		}

	} else {

		/* try default AUT0 key */

		if (cyberflex_verify_AUT0(sc_fd, cla, DEFAUT0, 8) < 0) {

			/* default AUT0 key failed; prompt for passphrase */

			if (get_AUT0(aut0) < 0 ||

			    cyberflex_verify_AUT0(sc_fd, cla, aut0, 8) < 0) {

				error("smartcard passphrase incorrect");

				return (-1);

			}

		}

	}

	return (0);

}

int

sc_put_key(Key *prv, const char *id)

{

	u_char *elements[NUM_RSA_KEY_ELEMENTS];

	u_char key_fid[2];

	u_char AUT0[EVP_MAX_MD_SIZE];

	int len, status = -1, i, fd = -1, ret;

	int sw = 0, cla = 0x00;

	for (i = 0; i < NUM_RSA_KEY_ELEMENTS; i++)

		elements[i] = NULL;

	COPY_RSA_KEY(q, 0);

	COPY_RSA_KEY(p, 1);

	COPY_RSA_KEY(iqmp, 2);

	COPY_RSA_KEY(dmq1, 3);

	COPY_RSA_KEY(dmp1, 4);

	COPY_RSA_KEY(n, 5);

	len = BN_num_bytes(prv->rsa->n);

	fd = sectok_friendly_open(id, STONOWAIT, &sw);

	if (fd < 0) {

		error("sectok_open failed: %s", sectok_get_sw(sw));

		goto done;

	}

	if (! sectok_cardpresent(fd)) {

		error("smartcard in reader %s not present", id);

		goto done;

	}

	ret = sectok_reset(fd, 0, NULL, &sw);

	if (ret <= 0) {

		error("sectok_reset failed: %s", sectok_get_sw(sw));

		goto done;

	}

	if ((cla = cyberflex_inq_class(fd)) < 0) {

		error("cyberflex_inq_class failed");

		goto done;

	}

	memcpy(AUT0, DEFAUT0, sizeof(DEFAUT0));

	if (cyberflex_verify_AUT0(fd, cla, AUT0, sizeof(DEFAUT0)) < 0) {

		if (get_AUT0(AUT0) < 0 ||

		    cyberflex_verify_AUT0(fd, cla, AUT0, sizeof(DEFAUT0)) < 0) {

			memset(AUT0, 0, sizeof(DEFAUT0));

			error("smartcard passphrase incorrect");

			goto done;

		}

	}

	memset(AUT0, 0, sizeof(DEFAUT0));

	key_fid[0] = 0x00;

	key_fid[1] = 0x12;

	if (cyberflex_load_rsa_priv(fd, cla, key_fid, 5, 8*len, elements,

	    &sw) < 0) {

		error("cyberflex_load_rsa_priv failed: %s", sectok_get_sw(sw));

		goto done;

	}

	if (!sectok_swOK(sw))

		goto done;

	logit("cyberflex_load_rsa_priv done");

	key_fid[0] = 0x73;

	key_fid[1] = 0x68;

	if (cyberflex_load_rsa_pub(fd, cla, key_fid, len, elements[5],

	    &sw) < 0) {

		error("cyberflex_load_rsa_pub failed: %s", sectok_get_sw(sw));

		goto done;

	}

	if (!sectok_swOK(sw))

		goto done;

	logit("cyberflex_load_rsa_pub done");

	status = 0;

done:

	memset(elements[0], '\0', BN_num_bytes(prv->rsa->q));

	memset(elements[1], '\0', BN_num_bytes(prv->rsa->p));

	memset(elements[2], '\0', BN_num_bytes(prv->rsa->iqmp));

	memset(elements[3], '\0', BN_num_bytes(prv->rsa->dmq1));

	memset(elements[4], '\0', BN_num_bytes(prv->rsa->dmp1));

	memset(elements[5], '\0', BN_num_bytes(prv->rsa->n));

	for (i = 0; i < NUM_RSA_KEY_ELEMENTS; i++)

		if (elements[i])

			xfree(elements[i]);

	if (fd != -1)

		sectok_close(fd);

	return (status);

}

char *

sc_get_key_label(Key *key)

{

	return xstrdup("smartcard key");

}

#endif /* SMARTCARD && USE_SECTOK */