scard.c - security/openssh-library - Rivoreo Source Code Repositories

 /*
  * 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"
 #ifdef SMARTCARD
 RCSID("$OpenBSD: scard.c,v 1.24 2002/03/25 17:34:27 markus Exp $");

 #include <openssl/evp.h>
 #include <sectok.h>

 #include "key.h"
 #include "log.h"
 #include "xmalloc.h"
 #include "readpass.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);

 /* 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 (!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 %d %s", key_size(k), p);
 	xfree(p);

 err:
 	if (n != NULL)
 		xfree(n);
 	sc_close();
 	return status;
 }

 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);
 }

 /* 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 = xmalloc((nkeys+1) * sizeof(Key *));

 	n = key_new(KEY_RSA1);
 	BN_copy(n->rsa->n, k->rsa->n);
 	BN_copy(n->rsa->e, k->rsa->e);
 	RSA_set_method(n->rsa, sc_get_rsa());
 	n->flags |= KEY_FLAG_EXT;
 	keys[0] = n;

 	n = key_new(KEY_RSA);
 	BN_copy(n->rsa->n, k->rsa->n);
 	BN_copy(n->rsa->e, k->rsa->e);
 	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;
 }

 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;
 	log("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;
 	log("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);
 }
 #endif /* SMARTCARD */
	/*
	* 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"
	#ifdef SMARTCARD
	RCSID("$OpenBSD: scard.c,v 1.24 2002/03/25 17:34:27 markus Exp $");

	#include <openssl/evp.h>
	#include <sectok.h>

	#include "key.h"
	#include "log.h"
	#include "xmalloc.h"
	#include "readpass.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);

	/* 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 (!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 %d %s", key_size(k), p);
	xfree(p);

	err:
	if (n != NULL)
	xfree(n);
	sc_close();
	return status;
	}

	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);
	}

	/* 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 = xmalloc((nkeys+1) * sizeof(Key *));

	n = key_new(KEY_RSA1);
	BN_copy(n->rsa->n, k->rsa->n);
	BN_copy(n->rsa->e, k->rsa->e);
	RSA_set_method(n->rsa, sc_get_rsa());
	n->flags \|= KEY_FLAG_EXT;
	keys[0] = n;

	n = key_new(KEY_RSA);
	BN_copy(n->rsa->n, k->rsa->n);
	BN_copy(n->rsa->e, k->rsa->e);
	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;
	}

	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;
	log("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;
	log("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);
	}
	#endif /* SMARTCARD */