scard.c

   1 /* $OpenBSD: scard.c,v 1.32 2006/03/25 13:17:02 djm Exp $ */
   2 /*
   3  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "includes.h"
  27 #if defined(SMARTCARD) && defined(USE_SECTOK)
  28
  29 #include <openssl/evp.h>
  30 #include <sectok.h>
  31
  32 #include "key.h"
  33 #include "log.h"
  34 #include "xmalloc.h"
  35 #include "misc.h"
  36 #include "scard.h"
  37
  38 #if OPENSSL_VERSION_NUMBER < 0x00907000L
  39 #define USE_ENGINE
  40 #define RSA_get_default_method RSA_get_default_openssl_method
  41 #else
  42 #endif
  43
  44 #ifdef USE_ENGINE
  45 #include <openssl/engine.h>
  46 #define sc_get_rsa sc_get_engine
  47 #else
  48 #define sc_get_rsa sc_get_rsa_method
  49 #endif
  50
  51 #define CLA_SSH 0x05
  52 #define INS_DECRYPT 0x10
  53 #define INS_GET_KEYLENGTH 0x20
  54 #define INS_GET_PUBKEY 0x30
  55 #define INS_GET_RESPONSE 0xc0
  56
  57 #define MAX_BUF_SIZE 256
  58
  59 u_char DEFAUT0[] = {0xad, 0x9f, 0x61, 0xfe, 0xfa, 0x20, 0xce, 0x63};
  60
  61 static int sc_fd = -1;
  62 static char *sc_reader_id = NULL;
  63 static char *sc_pin = NULL;
  64 static int cla = 0x00;  /* class */
  65
  66 static void sc_mk_digest(const char *pin, u_char *digest);
  67 static int get_AUT0(u_char *aut0);
  68 static int try_AUT0(void);
  69
  70 /* interface to libsectok */
  71
  72 static int
  73 sc_open(void)
  74 {
  75         int sw;
  76
  77         if (sc_fd >= 0)
  78                 return sc_fd;
  79
  80         sc_fd = sectok_friendly_open(sc_reader_id, STONOWAIT, &sw);
  81         if (sc_fd < 0) {
  82                 error("sectok_open failed: %s", sectok_get_sw(sw));
  83                 return SCARD_ERROR_FAIL;
  84         }
  85         if (! sectok_cardpresent(sc_fd)) {
  86                 debug("smartcard in reader %s not present, skipping",
  87                     sc_reader_id);
  88                 sc_close();
  89                 return SCARD_ERROR_NOCARD;
  90         }
  91         if (sectok_reset(sc_fd, 0, NULL, &sw) <= 0) {
  92                 error("sectok_reset failed: %s", sectok_get_sw(sw));
  93                 sc_fd = -1;
  94                 return SCARD_ERROR_FAIL;
  95         }
  96         if ((cla = cyberflex_inq_class(sc_fd)) < 0)
  97                 cla = 0;
  98
  99         debug("sc_open ok %d", sc_fd);
 100         return sc_fd;
 101 }
 102
 103 static int
 104 sc_enable_applet(void)
 105 {
 106         static u_char aid[] = {0xfc, 0x53, 0x73, 0x68, 0x2e, 0x62, 0x69, 0x6e};
 107         int sw = 0;
 108
 109         /* select applet id */
 110         sectok_apdu(sc_fd, cla, 0xa4, 0x04, 0, sizeof aid, aid, 0, NULL, &sw);
 111         if (!sectok_swOK(sw)) {
 112                 error("sectok_apdu failed: %s", sectok_get_sw(sw));
 113                 sc_close();
 114                 return -1;
 115         }
 116         return 0;
 117 }
 118
 119 static int
 120 sc_init(void)
 121 {
 122         int status;
 123
 124         status = sc_open();
 125         if (status == SCARD_ERROR_NOCARD) {
 126                 return SCARD_ERROR_NOCARD;
 127         }
 128         if (status < 0 ) {
 129                 error("sc_open failed");
 130                 return status;
 131         }
 132         if (sc_enable_applet() < 0) {
 133                 error("sc_enable_applet failed");
 134                 return SCARD_ERROR_APPLET;
 135         }
 136         return 0;
 137 }
 138
 139 static int
 140 sc_read_pubkey(Key * k)
 141 {
 142         u_char buf[2], *n;
 143         char *p;
 144         int len, sw, status = -1;
 145
 146         len = sw = 0;
 147         n = NULL;
 148
 149         if (sc_fd < 0) {
 150                 if (sc_init() < 0)
 151                         goto err;
 152         }
 153
 154         /* get key size */
 155         sectok_apdu(sc_fd, CLA_SSH, INS_GET_KEYLENGTH, 0, 0, 0, NULL,
 156             sizeof(buf), buf, &sw);
 157         if (!sectok_swOK(sw)) {
 158                 error("could not obtain key length: %s", sectok_get_sw(sw));
 159                 goto err;
 160         }
 161         len = (buf[0] << 8) | buf[1];
 162         len /= 8;
 163         debug("INS_GET_KEYLENGTH: len %d sw %s", len, sectok_get_sw(sw));
 164
 165         n = xmalloc(len);
 166         /* get n */
 167         sectok_apdu(sc_fd, CLA_SSH, INS_GET_PUBKEY, 0, 0, 0, NULL, len, n, &sw);
 168
 169         if (sw == 0x6982) {
 170                 if (try_AUT0() < 0)
 171                         goto err;
 172                 sectok_apdu(sc_fd, CLA_SSH, INS_GET_PUBKEY, 0, 0, 0, NULL, len, n, &sw);
 173         }
 174         if (!sectok_swOK(sw)) {
 175                 error("could not obtain public key: %s", sectok_get_sw(sw));
 176                 goto err;
 177         }
 178
 179         debug("INS_GET_KEYLENGTH: sw %s", sectok_get_sw(sw));
 180
 181         if (BN_bin2bn(n, len, k->rsa->n) == NULL) {
 182                 error("c_read_pubkey: BN_bin2bn failed");
 183                 goto err;
 184         }
 185
 186         /* currently the java applet just stores 'n' */
 187         if (!BN_set_word(k->rsa->e, 35)) {
 188                 error("c_read_pubkey: BN_set_word(e, 35) failed");
 189                 goto err;
 190         }
 191
 192         status = 0;
 193         p = key_fingerprint(k, SSH_FP_MD5, SSH_FP_HEX);
 194         debug("fingerprint %u %s", key_size(k), p);
 195         xfree(p);
 196
 197 err:
 198         if (n != NULL)
 199                 xfree(n);
 200         sc_close();
 201         return status;
 202 }
 203
 204 /* private key operations */
 205
 206 static int
 207 sc_private_decrypt(int flen, u_char *from, u_char *to, RSA *rsa,
 208     int padding)
 209 {
 210         u_char *padded = NULL;
 211         int sw, len, olen, status = -1;
 212
 213         debug("sc_private_decrypt called");
 214
 215         olen = len = sw = 0;
 216         if (sc_fd < 0) {
 217                 status = sc_init();
 218                 if (status < 0 )
 219                         goto err;
 220         }
 221         if (padding != RSA_PKCS1_PADDING)
 222                 goto err;
 223
 224         len = BN_num_bytes(rsa->n);
 225         padded = xmalloc(len);
 226
 227         sectok_apdu(sc_fd, CLA_SSH, INS_DECRYPT, 0, 0, len, from, len, padded, &sw);
 228
 229         if (sw == 0x6982) {
 230                 if (try_AUT0() < 0)
 231                         goto err;
 232                 sectok_apdu(sc_fd, CLA_SSH, INS_DECRYPT, 0, 0, len, from, len, padded, &sw);
 233         }
 234         if (!sectok_swOK(sw)) {
 235                 error("sc_private_decrypt: INS_DECRYPT failed: %s",
 236                     sectok_get_sw(sw));
 237                 goto err;
 238         }
 239         olen = RSA_padding_check_PKCS1_type_2(to, len, padded + 1, len - 1,
 240             len);
 241 err:
 242         if (padded)
 243                 xfree(padded);
 244         sc_close();
 245         return (olen >= 0 ? olen : status);
 246 }
 247
 248 static int
 249 sc_private_encrypt(int flen, u_char *from, u_char *to, RSA *rsa,
 250     int padding)
 251 {
 252         u_char *padded = NULL;
 253         int sw, len, status = -1;
 254
 255         len = sw = 0;
 256         if (sc_fd < 0) {
 257                 status = sc_init();
 258                 if (status < 0 )
 259                         goto err;
 260         }
 261         if (padding != RSA_PKCS1_PADDING)
 262                 goto err;
 263
 264         debug("sc_private_encrypt called");
 265         len = BN_num_bytes(rsa->n);
 266         padded = xmalloc(len);
 267
 268         if (RSA_padding_add_PKCS1_type_1(padded, len, (u_char *)from, flen) <= 0) {
 269                 error("RSA_padding_add_PKCS1_type_1 failed");
 270                 goto err;
 271         }
 272         sectok_apdu(sc_fd, CLA_SSH, INS_DECRYPT, 0, 0, len, padded, len, to, &sw);
 273         if (sw == 0x6982) {
 274                 if (try_AUT0() < 0)
 275                         goto err;
 276                 sectok_apdu(sc_fd, CLA_SSH, INS_DECRYPT, 0, 0, len, padded, len, to, &sw);
 277         }
 278         if (!sectok_swOK(sw)) {
 279                 error("sc_private_encrypt: INS_DECRYPT failed: %s",
 280                     sectok_get_sw(sw));
 281                 goto err;
 282         }
 283 err:
 284         if (padded)
 285                 xfree(padded);
 286         sc_close();
 287         return (len >= 0 ? len : status);
 288 }
 289
 290 /* called on free */
 291
 292 static int (*orig_finish)(RSA *rsa) = NULL;
 293
 294 static int
 295 sc_finish(RSA *rsa)
 296 {
 297         if (orig_finish)
 298                 orig_finish(rsa);
 299         sc_close();
 300         return 1;
 301 }
 302
 303 /* engine for overloading private key operations */
 304
 305 static RSA_METHOD *
 306 sc_get_rsa_method(void)
 307 {
 308         static RSA_METHOD smart_rsa;
 309         const RSA_METHOD *def = RSA_get_default_method();
 310
 311         /* use the OpenSSL version */
 312         memcpy(&smart_rsa, def, sizeof(smart_rsa));
 313
 314         smart_rsa.name          = "sectok";
 315
 316         /* overload */
 317         smart_rsa.rsa_priv_enc  = sc_private_encrypt;
 318         smart_rsa.rsa_priv_dec  = sc_private_decrypt;
 319
 320         /* save original */
 321         orig_finish             = def->finish;
 322         smart_rsa.finish        = sc_finish;
 323
 324         return &smart_rsa;
 325 }
 326
 327 #ifdef USE_ENGINE
 328 static ENGINE *
 329 sc_get_engine(void)
 330 {
 331         static ENGINE *smart_engine = NULL;
 332
 333         if ((smart_engine = ENGINE_new()) == NULL)
 334                 fatal("ENGINE_new failed");
 335
 336         ENGINE_set_id(smart_engine, "sectok");
 337         ENGINE_set_name(smart_engine, "libsectok");
 338
 339         ENGINE_set_RSA(smart_engine, sc_get_rsa_method());
 340         ENGINE_set_DSA(smart_engine, DSA_get_default_openssl_method());
 341         ENGINE_set_DH(smart_engine, DH_get_default_openssl_method());
 342         ENGINE_set_RAND(smart_engine, RAND_SSLeay());
 343         ENGINE_set_BN_mod_exp(smart_engine, BN_mod_exp);
 344
 345         return smart_engine;
 346 }
 347 #endif
 348
 349 void
 350 sc_close(void)
 351 {
 352         if (sc_fd >= 0) {
 353                 sectok_close(sc_fd);
 354                 sc_fd = -1;
 355         }
 356 }
 357
 358 Key **
 359 sc_get_keys(const char *id, const char *pin)
 360 {
 361         Key *k, *n, **keys;
 362         int status, nkeys = 2;
 363
 364         if (sc_reader_id != NULL)
 365                 xfree(sc_reader_id);
 366         sc_reader_id = xstrdup(id);
 367
 368         if (sc_pin != NULL)
 369                 xfree(sc_pin);
 370         sc_pin = (pin == NULL) ? NULL : xstrdup(pin);
 371
 372         k = key_new(KEY_RSA);
 373         if (k == NULL) {
 374                 return NULL;
 375         }
 376         status = sc_read_pubkey(k);
 377         if (status == SCARD_ERROR_NOCARD) {
 378                 key_free(k);
 379                 return NULL;
 380         }
 381         if (status < 0 ) {
 382                 error("sc_read_pubkey failed");
 383                 key_free(k);
 384                 return NULL;
 385         }
 386         keys = xcalloc((nkeys+1), sizeof(Key *));
 387
 388         n = key_new(KEY_RSA1);
 389         BN_copy(n->rsa->n, k->rsa->n);
 390         BN_copy(n->rsa->e, k->rsa->e);
 391         RSA_set_method(n->rsa, sc_get_rsa());
 392         n->flags |= KEY_FLAG_EXT;
 393         keys[0] = n;
 394
 395         n = key_new(KEY_RSA);
 396         BN_copy(n->rsa->n, k->rsa->n);
 397         BN_copy(n->rsa->e, k->rsa->e);
 398         RSA_set_method(n->rsa, sc_get_rsa());
 399         n->flags |= KEY_FLAG_EXT;
 400         keys[1] = n;
 401
 402         keys[2] = NULL;
 403
 404         key_free(k);
 405         return keys;
 406 }
 407
 408 #define NUM_RSA_KEY_ELEMENTS 5+1
 409 #define COPY_RSA_KEY(x, i) \
 410         do { \
 411                 len = BN_num_bytes(prv->rsa->x); \
 412                 elements[i] = xmalloc(len); \
 413                 debug("#bytes %d", len); \
 414                 if (BN_bn2bin(prv->rsa->x, elements[i]) < 0) \
 415                         goto done; \
 416         } while (0)
 417
 418 static void
 419 sc_mk_digest(const char *pin, u_char *digest)
 420 {
 421         const EVP_MD *evp_md = EVP_sha1();
 422         EVP_MD_CTX md;
 423
 424         EVP_DigestInit(&md, evp_md);
 425         EVP_DigestUpdate(&md, pin, strlen(pin));
 426         EVP_DigestFinal(&md, digest, NULL);
 427 }
 428
 429 static int
 430 get_AUT0(u_char *aut0)
 431 {
 432         char *pass;
 433
 434         pass = read_passphrase("Enter passphrase for smartcard: ", RP_ALLOW_STDIN);
 435         if (pass == NULL)
 436                 return -1;
 437         if (!strcmp(pass, "-")) {
 438                 memcpy(aut0, DEFAUT0, sizeof DEFAUT0);
 439                 return 0;
 440         }
 441         sc_mk_digest(pass, aut0);
 442         memset(pass, 0, strlen(pass));
 443         xfree(pass);
 444         return 0;
 445 }
 446
 447 static int
 448 try_AUT0(void)
 449 {
 450         u_char aut0[EVP_MAX_MD_SIZE];
 451
 452         /* permission denied; try PIN if provided */
 453         if (sc_pin && strlen(sc_pin) > 0) {
 454                 sc_mk_digest(sc_pin, aut0);
 455                 if (cyberflex_verify_AUT0(sc_fd, cla, aut0, 8) < 0) {
 456                         error("smartcard passphrase incorrect");
 457                         return (-1);
 458                 }
 459         } else {
 460                 /* try default AUT0 key */
 461                 if (cyberflex_verify_AUT0(sc_fd, cla, DEFAUT0, 8) < 0) {
 462                         /* default AUT0 key failed; prompt for passphrase */
 463                         if (get_AUT0(aut0) < 0 ||
 464                             cyberflex_verify_AUT0(sc_fd, cla, aut0, 8) < 0) {
 465                                 error("smartcard passphrase incorrect");
 466                                 return (-1);
 467                         }
 468                 }
 469         }
 470         return (0);
 471 }
 472
 473 int
 474 sc_put_key(Key *prv, const char *id)
 475 {
 476         u_char *elements[NUM_RSA_KEY_ELEMENTS];
 477         u_char key_fid[2];
 478         u_char AUT0[EVP_MAX_MD_SIZE];
 479         int len, status = -1, i, fd = -1, ret;
 480         int sw = 0, cla = 0x00;
 481
 482         for (i = 0; i < NUM_RSA_KEY_ELEMENTS; i++)
 483                 elements[i] = NULL;
 484
 485         COPY_RSA_KEY(q, 0);
 486         COPY_RSA_KEY(p, 1);
 487         COPY_RSA_KEY(iqmp, 2);
 488         COPY_RSA_KEY(dmq1, 3);
 489         COPY_RSA_KEY(dmp1, 4);
 490         COPY_RSA_KEY(n, 5);
 491         len = BN_num_bytes(prv->rsa->n);
 492         fd = sectok_friendly_open(id, STONOWAIT, &sw);
 493         if (fd < 0) {
 494                 error("sectok_open failed: %s", sectok_get_sw(sw));
 495                 goto done;
 496         }
 497         if (! sectok_cardpresent(fd)) {
 498                 error("smartcard in reader %s not present", id);
 499                 goto done;
 500         }
 501         ret = sectok_reset(fd, 0, NULL, &sw);
 502         if (ret <= 0) {
 503                 error("sectok_reset failed: %s", sectok_get_sw(sw));
 504                 goto done;
 505         }
 506         if ((cla = cyberflex_inq_class(fd)) < 0) {
 507                 error("cyberflex_inq_class failed");
 508                 goto done;
 509         }
 510         memcpy(AUT0, DEFAUT0, sizeof(DEFAUT0));
 511         if (cyberflex_verify_AUT0(fd, cla, AUT0, sizeof(DEFAUT0)) < 0) {
 512                 if (get_AUT0(AUT0) < 0 ||
 513                     cyberflex_verify_AUT0(fd, cla, AUT0, sizeof(DEFAUT0)) < 0) {
 514                         memset(AUT0, 0, sizeof(DEFAUT0));
 515                         error("smartcard passphrase incorrect");
 516                         goto done;
 517                 }
 518         }
 519         memset(AUT0, 0, sizeof(DEFAUT0));
 520         key_fid[0] = 0x00;
 521         key_fid[1] = 0x12;
 522         if (cyberflex_load_rsa_priv(fd, cla, key_fid, 5, 8*len, elements,
 523             &sw) < 0) {
 524                 error("cyberflex_load_rsa_priv failed: %s", sectok_get_sw(sw));
 525                 goto done;
 526         }
 527         if (!sectok_swOK(sw))
 528                 goto done;
 529         logit("cyberflex_load_rsa_priv done");
 530         key_fid[0] = 0x73;
 531         key_fid[1] = 0x68;
 532         if (cyberflex_load_rsa_pub(fd, cla, key_fid, len, elements[5],
 533             &sw) < 0) {
 534                 error("cyberflex_load_rsa_pub failed: %s", sectok_get_sw(sw));
 535                 goto done;
 536         }
 537         if (!sectok_swOK(sw))
 538                 goto done;
 539         logit("cyberflex_load_rsa_pub done");
 540         status = 0;
 541
 542 done:
 543         memset(elements[0], '\0', BN_num_bytes(prv->rsa->q));
 544         memset(elements[1], '\0', BN_num_bytes(prv->rsa->p));
 545         memset(elements[2], '\0', BN_num_bytes(prv->rsa->iqmp));
 546         memset(elements[3], '\0', BN_num_bytes(prv->rsa->dmq1));
 547         memset(elements[4], '\0', BN_num_bytes(prv->rsa->dmp1));
 548         memset(elements[5], '\0', BN_num_bytes(prv->rsa->n));
 549
 550         for (i = 0; i < NUM_RSA_KEY_ELEMENTS; i++)
 551                 if (elements[i])
 552                         xfree(elements[i]);
 553         if (fd != -1)
 554                 sectok_close(fd);
 555         return (status);
 556 }
 557
 558 char *
 559 sc_get_key_label(Key *key)
 560 {
 561         return xstrdup("smartcard key");
 562 }
 563
 564 #endif /* SMARTCARD && USE_SECTOK */