openssh/scard.c
Ben Lindstrom 43a5e2f70e - rees@cvs.openbsd.org 2002/03/26 18:46:59
[scard.c]
     try_AUT0 in read_pubkey too, for those paranoid few who want to acl 'sh'
2002-03-27 17:33:17 +00:00

558 lines
12 KiB
C

/*
* 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 1.25 2002/03/26 18:46:59 rees 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);
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 %d %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 = 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;
}
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;
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 */