scard-opensc.c

   1 /*
   2  * Copyright (c) 2002 Juha Yrjölä.  All rights reserved.
   3  * Copyright (c) 2001 Markus Friedl.
   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_OPENSC)
  28
  29 #include <openssl/evp.h>
  30 #include <openssl/x509.h>
  31
  32 #include <opensc/opensc.h>
  33 #include <opensc/pkcs15.h>
  34
  35 #include "key.h"
  36 #include "log.h"
  37 #include "xmalloc.h"
  38 #include "misc.h"
  39 #include "scard.h"
  40
  41 #if OPENSSL_VERSION_NUMBER < 0x00907000L && defined(CRYPTO_LOCK_ENGINE)
  42 #define USE_ENGINE
  43 #define RSA_get_default_method RSA_get_default_openssl_method
  44 #else
  45 #endif
  46
  47 #ifdef USE_ENGINE
  48 #include <openssl/engine.h>
  49 #define sc_get_rsa sc_get_engine
  50 #else
  51 #define sc_get_rsa sc_get_rsa_method
  52 #endif
  53
  54 static int sc_reader_id;
  55 static sc_context_t *ctx = NULL;
  56 static sc_card_t *card = NULL;
  57 static sc_pkcs15_card_t *p15card = NULL;
  58
  59 static char *sc_pin = NULL;
  60
  61 struct sc_priv_data
  62 {
  63         struct sc_pkcs15_id cert_id;
  64         int ref_count;
  65 };
  66
  67 void
  68 sc_close(void)
  69 {
  70         if (p15card) {
  71                 sc_pkcs15_unbind(p15card);
  72                 p15card = NULL;
  73         }
  74         if (card) {
  75                 sc_disconnect_card(card, 0);
  76                 card = NULL;
  77         }
  78         if (ctx) {
  79                 sc_release_context(ctx);
  80                 ctx = NULL;
  81         }
  82 }
  83
  84 static int
  85 sc_init(void)
  86 {
  87         int r;
  88
  89         r = sc_establish_context(&ctx, "openssh");
  90         if (r)
  91                 goto err;
  92         if (sc_reader_id >= ctx->reader_count) {
  93                 r = SC_ERROR_NO_READERS_FOUND;
  94                 error("Illegal reader number %d (max %d)", sc_reader_id,
  95                     ctx->reader_count -1);
  96                 goto err;
  97         }
  98         r = sc_connect_card(ctx->reader[sc_reader_id], 0, &card);
  99         if (r)
 100                 goto err;
 101         r = sc_pkcs15_bind(card, &p15card);
 102         if (r)
 103                 goto err;
 104         return 0;
 105 err:
 106         sc_close();
 107         return r;
 108 }
 109
 110 /* private key operations */
 111
 112 static int
 113 sc_prkey_op_init(RSA *rsa, struct sc_pkcs15_object **key_obj_out,
 114         unsigned int usage)
 115 {
 116         int r;
 117         struct sc_priv_data *priv;
 118         struct sc_pkcs15_object *key_obj;
 119         struct sc_pkcs15_prkey_info *key;
 120         struct sc_pkcs15_object *pin_obj;
 121         struct sc_pkcs15_pin_info *pin;
 122
 123         priv = (struct sc_priv_data *) RSA_get_app_data(rsa);
 124         if (priv == NULL)
 125                 return -1;
 126         if (p15card == NULL) {
 127                 sc_close();
 128                 r = sc_init();
 129                 if (r) {
 130                         error("SmartCard init failed: %s", sc_strerror(r));
 131                         goto err;
 132                 }
 133         }
 134         r = sc_pkcs15_find_prkey_by_id_usage(p15card, &priv->cert_id,
 135                 usage, &key_obj);
 136         if (r) {
 137                 error("Unable to find private key from SmartCard: %s",
 138                       sc_strerror(r));
 139                 goto err;
 140         }
 141         key = key_obj->data;
 142         r = sc_pkcs15_find_pin_by_auth_id(p15card, &key_obj->auth_id,
 143                                           &pin_obj);
 144         if (r == SC_ERROR_OBJECT_NOT_FOUND) {
 145                 /* no pin required */
 146                 r = sc_lock(card);
 147                 if (r) {
 148                         error("Unable to lock smartcard: %s", sc_strerror(r));
 149                         goto err;
 150                 }
 151                 *key_obj_out = key_obj;
 152                 return 0;
 153         } else if (r) {
 154                 error("Unable to find PIN object from SmartCard: %s",
 155                       sc_strerror(r));
 156                 goto err;
 157         }
 158         pin = pin_obj->data;
 159         r = sc_lock(card);
 160         if (r) {
 161                 error("Unable to lock smartcard: %s", sc_strerror(r));
 162                 goto err;
 163         }
 164         if (sc_pin != NULL) {
 165                 r = sc_pkcs15_verify_pin(p15card, pin, sc_pin,
 166                                          strlen(sc_pin));
 167                 if (r) {
 168                         sc_unlock(card);
 169                         error("PIN code verification failed: %s",
 170                               sc_strerror(r));
 171                         goto err;
 172                 }
 173         }
 174         *key_obj_out = key_obj;
 175         return 0;
 176 err:
 177         sc_close();
 178         return -1;
 179 }
 180
 181 #define SC_USAGE_DECRYPT        SC_PKCS15_PRKEY_USAGE_DECRYPT | \
 182                                 SC_PKCS15_PRKEY_USAGE_UNWRAP
 183
 184 static int
 185 sc_private_decrypt(int flen, u_char *from, u_char *to, RSA *rsa,
 186     int padding)
 187 {
 188         struct sc_pkcs15_object *key_obj;
 189         int r;
 190
 191         if (padding != RSA_PKCS1_PADDING)
 192                 return -1;
 193         r = sc_prkey_op_init(rsa, &key_obj, SC_USAGE_DECRYPT);
 194         if (r)
 195                 return -1;
 196         r = sc_pkcs15_decipher(p15card, key_obj, SC_ALGORITHM_RSA_PAD_PKCS1,
 197             from, flen, to, flen);
 198         sc_unlock(card);
 199         if (r < 0) {
 200                 error("sc_pkcs15_decipher() failed: %s", sc_strerror(r));
 201                 goto err;
 202         }
 203         return r;
 204 err:
 205         sc_close();
 206         return -1;
 207 }
 208
 209 #define SC_USAGE_SIGN           SC_PKCS15_PRKEY_USAGE_SIGN | \
 210                                 SC_PKCS15_PRKEY_USAGE_SIGNRECOVER
 211
 212 static int
 213 sc_sign(int type, u_char *m, unsigned int m_len,
 214         unsigned char *sigret, unsigned int *siglen, RSA *rsa)
 215 {
 216         struct sc_pkcs15_object *key_obj;
 217         int r;
 218         unsigned long flags = 0;
 219
 220         /* XXX: sc_prkey_op_init will search for a pkcs15 private
 221          * key object with the sign or signrecover usage flag set.
 222          * If the signing key has only the non-repudiation flag set
 223          * the key will be rejected as using a non-repudiation key
 224          * for authentication is not recommended. Note: This does not
 225          * prevent the use of a non-repudiation key for authentication
 226          * if the sign or signrecover flag is set as well.
 227          */
 228         r = sc_prkey_op_init(rsa, &key_obj, SC_USAGE_SIGN);
 229         if (r)
 230                 return -1;
 231         /* FIXME: length of sigret correct? */
 232         /* FIXME: check 'type' and modify flags accordingly */
 233         flags = SC_ALGORITHM_RSA_PAD_PKCS1 | SC_ALGORITHM_RSA_HASH_SHA1;
 234         r = sc_pkcs15_compute_signature(p15card, key_obj, flags,
 235                                         m, m_len, sigret, RSA_size(rsa));
 236         sc_unlock(card);
 237         if (r < 0) {
 238                 error("sc_pkcs15_compute_signature() failed: %s",
 239                       sc_strerror(r));
 240                 goto err;
 241         }
 242         *siglen = r;
 243         return 1;
 244 err:
 245         sc_close();
 246         return 0;
 247 }
 248
 249 static int
 250 sc_private_encrypt(int flen, u_char *from, u_char *to, RSA *rsa,
 251     int padding)
 252 {
 253         error("Private key encryption not supported");
 254         return -1;
 255 }
 256
 257 /* called on free */
 258
 259 static int (*orig_finish)(RSA *rsa) = NULL;
 260
 261 static int
 262 sc_finish(RSA *rsa)
 263 {
 264         struct sc_priv_data *priv;
 265
 266         priv = RSA_get_app_data(rsa);
 267         priv->ref_count--;
 268         if (priv->ref_count == 0) {
 269                 free(priv);
 270                 sc_close();
 271         }
 272         if (orig_finish)
 273                 orig_finish(rsa);
 274         return 1;
 275 }
 276
 277 /* engine for overloading private key operations */
 278
 279 static RSA_METHOD *
 280 sc_get_rsa_method(void)
 281 {
 282         static RSA_METHOD smart_rsa;
 283         const RSA_METHOD *def = RSA_get_default_method();
 284
 285         /* use the OpenSSL version */
 286         memcpy(&smart_rsa, def, sizeof(smart_rsa));
 287
 288         smart_rsa.name          = "opensc";
 289
 290         /* overload */
 291         smart_rsa.rsa_priv_enc  = sc_private_encrypt;
 292         smart_rsa.rsa_priv_dec  = sc_private_decrypt;
 293         smart_rsa.rsa_sign      = sc_sign;
 294
 295         /* save original */
 296         orig_finish             = def->finish;
 297         smart_rsa.finish        = sc_finish;
 298
 299         return &smart_rsa;
 300 }
 301
 302 #ifdef USE_ENGINE
 303 static ENGINE *
 304 sc_get_engine(void)
 305 {
 306         static ENGINE *smart_engine = NULL;
 307
 308         if ((smart_engine = ENGINE_new()) == NULL)
 309                 fatal("ENGINE_new failed");
 310
 311         ENGINE_set_id(smart_engine, "opensc");
 312         ENGINE_set_name(smart_engine, "OpenSC");
 313
 314         ENGINE_set_RSA(smart_engine, sc_get_rsa_method());
 315         ENGINE_set_DSA(smart_engine, DSA_get_default_openssl_method());
 316         ENGINE_set_DH(smart_engine, DH_get_default_openssl_method());
 317         ENGINE_set_RAND(smart_engine, RAND_SSLeay());
 318         ENGINE_set_BN_mod_exp(smart_engine, BN_mod_exp);
 319
 320         return smart_engine;
 321 }
 322 #endif
 323
 324 static void
 325 convert_rsa_to_rsa1(Key * in, Key * out)
 326 {
 327         struct sc_priv_data *priv;
 328
 329         out->rsa->flags = in->rsa->flags;
 330         out->flags = in->flags;
 331         RSA_set_method(out->rsa, RSA_get_method(in->rsa));
 332         BN_copy(out->rsa->n, in->rsa->n);
 333         BN_copy(out->rsa->e, in->rsa->e);
 334         priv = RSA_get_app_data(in->rsa);
 335         priv->ref_count++;
 336         RSA_set_app_data(out->rsa, priv);
 337         return;
 338 }
 339
 340 static int
 341 sc_read_pubkey(Key * k, const struct sc_pkcs15_object *cert_obj)
 342 {
 343         int r;
 344         sc_pkcs15_cert_t *cert = NULL;
 345         struct sc_priv_data *priv = NULL;
 346         sc_pkcs15_cert_info_t *cinfo = cert_obj->data;
 347
 348         X509 *x509 = NULL;
 349         EVP_PKEY *pubkey = NULL;
 350         u8 *p;
 351         char *tmp;
 352
 353         debug("sc_read_pubkey() with cert id %02X", cinfo->id.value[0]);
 354         r = sc_pkcs15_read_certificate(p15card, cinfo, &cert);
 355         if (r) {
 356                 logit("Certificate read failed: %s", sc_strerror(r));
 357                 goto err;
 358         }
 359         x509 = X509_new();
 360         if (x509 == NULL) {
 361                 r = -1;
 362                 goto err;
 363         }
 364         p = cert->data;
 365         if (!d2i_X509(&x509, &p, cert->data_len)) {
 366                 logit("Unable to parse X.509 certificate");
 367                 r = -1;
 368                 goto err;
 369         }
 370         sc_pkcs15_free_certificate(cert);
 371         cert = NULL;
 372         pubkey = X509_get_pubkey(x509);
 373         X509_free(x509);
 374         x509 = NULL;
 375         if (pubkey->type != EVP_PKEY_RSA) {
 376                 logit("Public key is of unknown type");
 377                 r = -1;
 378                 goto err;
 379         }
 380         k->rsa = EVP_PKEY_get1_RSA(pubkey);
 381         EVP_PKEY_free(pubkey);
 382
 383         k->rsa->flags |= RSA_FLAG_SIGN_VER;
 384         RSA_set_method(k->rsa, sc_get_rsa_method());
 385         priv = xmalloc(sizeof(struct sc_priv_data));
 386         priv->cert_id = cinfo->id;
 387         priv->ref_count = 1;
 388         RSA_set_app_data(k->rsa, priv);
 389
 390         k->flags = KEY_FLAG_EXT;
 391         tmp = key_fingerprint(k, SSH_FP_MD5, SSH_FP_HEX);
 392         debug("fingerprint %d %s", key_size(k), tmp);
 393         xfree(tmp);
 394
 395         return 0;
 396 err:
 397         if (cert)
 398                 sc_pkcs15_free_certificate(cert);
 399         if (pubkey)
 400                 EVP_PKEY_free(pubkey);
 401         if (x509)
 402                 X509_free(x509);
 403         return r;
 404 }
 405
 406 Key **
 407 sc_get_keys(const char *id, const char *pin)
 408 {
 409         Key *k, **keys;
 410         int i, r, real_count = 0, key_count;
 411         sc_pkcs15_id_t cert_id;
 412         sc_pkcs15_object_t *certs[32];
 413         char *buf = xstrdup(id), *p;
 414
 415         debug("sc_get_keys called: id = %s", id);
 416
 417         if (sc_pin != NULL)
 418                 xfree(sc_pin);
 419         sc_pin = (pin == NULL) ? NULL : xstrdup(pin);
 420
 421         cert_id.len = 0;
 422         if ((p = strchr(buf, ':')) != NULL) {
 423                 *p = 0;
 424                 p++;
 425                 sc_pkcs15_hex_string_to_id(p, &cert_id);
 426         }
 427         r = sscanf(buf, "%d", &sc_reader_id);
 428         xfree(buf);
 429         if (r != 1)
 430                 goto err;
 431         if (p15card == NULL) {
 432                 sc_close();
 433                 r = sc_init();
 434                 if (r) {
 435                         error("Smartcard init failed: %s", sc_strerror(r));
 436                         goto err;
 437                 }
 438         }
 439         if (cert_id.len) {
 440                 r = sc_pkcs15_find_cert_by_id(p15card, &cert_id, &certs[0]);
 441                 if (r < 0)
 442                         goto err;
 443                 key_count = 1;
 444         } else {
 445                 r = sc_pkcs15_get_objects(p15card, SC_PKCS15_TYPE_CERT_X509,
 446                                           certs, 32);
 447                 if (r == 0) {
 448                         logit("No certificates found on smartcard");
 449                         r = -1;
 450                         goto err;
 451                 } else if (r < 0) {
 452                         error("Certificate enumeration failed: %s",
 453                               sc_strerror(r));
 454                         goto err;
 455                 }
 456                 key_count = r;
 457         }
 458         if (key_count > 1024)
 459                 fatal("Too many keys (%u), expected <= 1024", key_count);
 460         keys = xcalloc(key_count * 2 + 1, sizeof(Key *));
 461         for (i = 0; i < key_count; i++) {
 462                 sc_pkcs15_object_t *tmp_obj = NULL;
 463                 cert_id = ((sc_pkcs15_cert_info_t *)(certs[i]->data))->id;
 464                 if (sc_pkcs15_find_prkey_by_id(p15card, &cert_id, &tmp_obj))
 465                         /* skip the public key (certificate) if no
 466                          * corresponding private key is present */
 467                         continue;
 468                 k = key_new(KEY_RSA);
 469                 if (k == NULL)
 470                         break;
 471                 r = sc_read_pubkey(k, certs[i]);
 472                 if (r) {
 473                         error("sc_read_pubkey failed: %s", sc_strerror(r));
 474                         key_free(k);
 475                         continue;
 476                 }
 477                 keys[real_count] = k;
 478                 real_count++;
 479                 k = key_new(KEY_RSA1);
 480                 if (k == NULL)
 481                         break;
 482                 convert_rsa_to_rsa1(keys[real_count-1], k);
 483                 keys[real_count] = k;
 484                 real_count++;
 485         }
 486         keys[real_count] = NULL;
 487
 488         return keys;
 489 err:
 490         sc_close();
 491         return NULL;
 492 }
 493
 494 int
 495 sc_put_key(Key *prv, const char *id)
 496 {
 497         error("key uploading not yet supported");
 498         return -1;
 499 }
 500
 501 char *
 502 sc_get_key_label(Key *key)
 503 {
 504         int r;
 505         const struct sc_priv_data *priv;
 506         struct sc_pkcs15_object *key_obj;
 507
 508         priv = (const struct sc_priv_data *) RSA_get_app_data(key->rsa);
 509         if (priv == NULL || p15card == NULL) {
 510                 logit("SmartCard key not loaded");
 511                 /* internal error => return default label */
 512                 return xstrdup("smartcard key");
 513         }
 514         r = sc_pkcs15_find_prkey_by_id(p15card, &priv->cert_id, &key_obj);
 515         if (r) {
 516                 logit("Unable to find private key from SmartCard: %s",
 517                       sc_strerror(r));
 518                 return xstrdup("smartcard key");
 519         }
 520         if (key_obj == NULL || key_obj->label == NULL)
 521                 /* the optional PKCS#15 label does not exists
 522                  * => return the default label */
 523                 return xstrdup("smartcard key");
 524         return xstrdup(key_obj->label);
 525 }
 526
 527 #endif /* SMARTCARD */