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 <sys/types.h>
  30
  31 #include <openssl/evp.h>
  32 #include <openssl/x509.h>
  33
  34 #include <stdarg.h>
  35 #include <string.h>
  36
  37 #include <opensc/opensc.h>
  38 #include <opensc/pkcs15.h>
  39
  40 #include "key.h"
  41 #include "log.h"
  42 #include "xmalloc.h"
  43 #include "misc.h"
  44 #include "scard.h"
  45
  46 #if OPENSSL_VERSION_NUMBER < 0x00907000L && defined(CRYPTO_LOCK_ENGINE)
  47 #define USE_ENGINE
  48 #define RSA_get_default_method RSA_get_default_openssl_method
  49 #else
  50 #endif
  51
  52 #ifdef USE_ENGINE
  53 #include <openssl/engine.h>
  54 #define sc_get_rsa sc_get_engine
  55 #else
  56 #define sc_get_rsa sc_get_rsa_method
  57 #endif
  58
  59 static int sc_reader_id;
  60 static sc_context_t *ctx = NULL;
  61 static sc_card_t *card = NULL;
  62 static sc_pkcs15_card_t *p15card = NULL;
  63
  64 static char *sc_pin = NULL;
  65
  66 struct sc_priv_data
  67 {
  68         struct sc_pkcs15_id cert_id;
  69         int ref_count;
  70 };
  71
  72 void
  73 sc_close(void)
  74 {
  75         if (p15card) {
  76                 sc_pkcs15_unbind(p15card);
  77                 p15card = NULL;
  78         }
  79         if (card) {
  80                 sc_disconnect_card(card, 0);
  81                 card = NULL;
  82         }
  83         if (ctx) {
  84                 sc_release_context(ctx);
  85                 ctx = NULL;
  86         }
  87 }
  88
  89 static int
  90 sc_init(void)
  91 {
  92         int r;
  93
  94         r = sc_establish_context(&ctx, "openssh");
  95         if (r)
  96                 goto err;
  97         if (sc_reader_id >= ctx->reader_count) {
  98                 r = SC_ERROR_NO_READERS_FOUND;
  99                 error("Illegal reader number %d (max %d)", sc_reader_id,
 100                     ctx->reader_count -1);
 101                 goto err;
 102         }
 103         r = sc_connect_card(ctx->reader[sc_reader_id], 0, &card);
 104         if (r)
 105                 goto err;
 106         r = sc_pkcs15_bind(card, &p15card);
 107         if (r)
 108                 goto err;
 109         return 0;
 110 err:
 111         sc_close();
 112         return r;
 113 }
 114
 115 /* private key operations */
 116
 117 static int
 118 sc_prkey_op_init(RSA *rsa, struct sc_pkcs15_object **key_obj_out,
 119         unsigned int usage)
 120 {
 121         int r;
 122         struct sc_priv_data *priv;
 123         struct sc_pkcs15_object *key_obj;
 124         struct sc_pkcs15_prkey_info *key;
 125         struct sc_pkcs15_object *pin_obj;
 126         struct sc_pkcs15_pin_info *pin;
 127
 128         priv = (struct sc_priv_data *) RSA_get_app_data(rsa);
 129         if (priv == NULL)
 130                 return -1;
 131         if (p15card == NULL) {
 132                 sc_close();
 133                 r = sc_init();
 134                 if (r) {
 135                         error("SmartCard init failed: %s", sc_strerror(r));
 136                         goto err;
 137                 }
 138         }
 139         r = sc_pkcs15_find_prkey_by_id_usage(p15card, &priv->cert_id,
 140                 usage, &key_obj);
 141         if (r) {
 142                 error("Unable to find private key from SmartCard: %s",
 143                       sc_strerror(r));
 144                 goto err;
 145         }
 146         key = key_obj->data;
 147         r = sc_pkcs15_find_pin_by_auth_id(p15card, &key_obj->auth_id,
 148                                           &pin_obj);
 149         if (r == SC_ERROR_OBJECT_NOT_FOUND) {
 150                 /* no pin required */
 151                 r = sc_lock(card);
 152                 if (r) {
 153                         error("Unable to lock smartcard: %s", sc_strerror(r));
 154                         goto err;
 155                 }
 156                 *key_obj_out = key_obj;
 157                 return 0;
 158         } else if (r) {
 159                 error("Unable to find PIN object from SmartCard: %s",
 160                       sc_strerror(r));
 161                 goto err;
 162         }
 163         pin = pin_obj->data;
 164         r = sc_lock(card);
 165         if (r) {
 166                 error("Unable to lock smartcard: %s", sc_strerror(r));
 167                 goto err;
 168         }
 169         if (sc_pin != NULL) {
 170                 r = sc_pkcs15_verify_pin(p15card, pin, sc_pin,
 171                                          strlen(sc_pin));
 172                 if (r) {
 173                         sc_unlock(card);
 174                         error("PIN code verification failed: %s",
 175                               sc_strerror(r));
 176                         goto err;
 177                 }
 178         }
 179         *key_obj_out = key_obj;
 180         return 0;
 181 err:
 182         sc_close();
 183         return -1;
 184 }
 185
 186 #define SC_USAGE_DECRYPT        SC_PKCS15_PRKEY_USAGE_DECRYPT | \
 187                                 SC_PKCS15_PRKEY_USAGE_UNWRAP
 188
 189 static int
 190 sc_private_decrypt(int flen, u_char *from, u_char *to, RSA *rsa,
 191     int padding)
 192 {
 193         struct sc_pkcs15_object *key_obj;
 194         int r;
 195
 196         if (padding != RSA_PKCS1_PADDING)
 197                 return -1;
 198         r = sc_prkey_op_init(rsa, &key_obj, SC_USAGE_DECRYPT);
 199         if (r)
 200                 return -1;
 201         r = sc_pkcs15_decipher(p15card, key_obj, SC_ALGORITHM_RSA_PAD_PKCS1,
 202             from, flen, to, flen);
 203         sc_unlock(card);
 204         if (r < 0) {
 205                 error("sc_pkcs15_decipher() failed: %s", sc_strerror(r));
 206                 goto err;
 207         }
 208         return r;
 209 err:
 210         sc_close();
 211         return -1;
 212 }
 213
 214 #define SC_USAGE_SIGN           SC_PKCS15_PRKEY_USAGE_SIGN | \
 215                                 SC_PKCS15_PRKEY_USAGE_SIGNRECOVER
 216
 217 static int
 218 sc_sign(int type, u_char *m, unsigned int m_len,
 219         unsigned char *sigret, unsigned int *siglen, RSA *rsa)
 220 {
 221         struct sc_pkcs15_object *key_obj;
 222         int r;
 223         unsigned long flags = 0;
 224
 225         /* XXX: sc_prkey_op_init will search for a pkcs15 private
 226          * key object with the sign or signrecover usage flag set.
 227          * If the signing key has only the non-repudiation flag set
 228          * the key will be rejected as using a non-repudiation key
 229          * for authentication is not recommended. Note: This does not
 230          * prevent the use of a non-repudiation key for authentication
 231          * if the sign or signrecover flag is set as well.
 232          */
 233         r = sc_prkey_op_init(rsa, &key_obj, SC_USAGE_SIGN);
 234         if (r)
 235                 return -1;
 236         /* FIXME: length of sigret correct? */
 237         /* FIXME: check 'type' and modify flags accordingly */
 238         flags = SC_ALGORITHM_RSA_PAD_PKCS1 | SC_ALGORITHM_RSA_HASH_SHA1;
 239         r = sc_pkcs15_compute_signature(p15card, key_obj, flags,
 240                                         m, m_len, sigret, RSA_size(rsa));
 241         sc_unlock(card);
 242         if (r < 0) {
 243                 error("sc_pkcs15_compute_signature() failed: %s",
 244                       sc_strerror(r));
 245                 goto err;
 246         }
 247         *siglen = r;
 248         return 1;
 249 err:
 250         sc_close();
 251         return 0;
 252 }
 253
 254 static int
 255 sc_private_encrypt(int flen, u_char *from, u_char *to, RSA *rsa,
 256     int padding)
 257 {
 258         error("Private key encryption not supported");
 259         return -1;
 260 }
 261
 262 /* called on free */
 263
 264 static int (*orig_finish)(RSA *rsa) = NULL;
 265
 266 static int
 267 sc_finish(RSA *rsa)
 268 {
 269         struct sc_priv_data *priv;
 270
 271         priv = RSA_get_app_data(rsa);
 272         priv->ref_count--;
 273         if (priv->ref_count == 0) {
 274                 free(priv);
 275                 sc_close();
 276         }
 277         if (orig_finish)
 278                 orig_finish(rsa);
 279         return 1;
 280 }
 281
 282 /* engine for overloading private key operations */
 283
 284 static RSA_METHOD *
 285 sc_get_rsa_method(void)
 286 {
 287         static RSA_METHOD smart_rsa;
 288         const RSA_METHOD *def = RSA_get_default_method();
 289
 290         /* use the OpenSSL version */
 291         memcpy(&smart_rsa, def, sizeof(smart_rsa));
 292
 293         smart_rsa.name          = "opensc";
 294
 295         /* overload */
 296         smart_rsa.rsa_priv_enc  = sc_private_encrypt;
 297         smart_rsa.rsa_priv_dec  = sc_private_decrypt;
 298         smart_rsa.rsa_sign      = sc_sign;
 299
 300         /* save original */
 301         orig_finish             = def->finish;
 302         smart_rsa.finish        = sc_finish;
 303
 304         return &smart_rsa;
 305 }
 306
 307 #ifdef USE_ENGINE
 308 static ENGINE *
 309 sc_get_engine(void)
 310 {
 311         static ENGINE *smart_engine = NULL;
 312
 313         if ((smart_engine = ENGINE_new()) == NULL)
 314                 fatal("ENGINE_new failed");
 315
 316         ENGINE_set_id(smart_engine, "opensc");
 317         ENGINE_set_name(smart_engine, "OpenSC");
 318
 319         ENGINE_set_RSA(smart_engine, sc_get_rsa_method());
 320         ENGINE_set_DSA(smart_engine, DSA_get_default_openssl_method());
 321         ENGINE_set_DH(smart_engine, DH_get_default_openssl_method());
 322         ENGINE_set_RAND(smart_engine, RAND_SSLeay());
 323         ENGINE_set_BN_mod_exp(smart_engine, BN_mod_exp);
 324
 325         return smart_engine;
 326 }
 327 #endif
 328
 329 static void
 330 convert_rsa_to_rsa1(Key * in, Key * out)
 331 {
 332         struct sc_priv_data *priv;
 333
 334         out->rsa->flags = in->rsa->flags;
 335         out->flags = in->flags;
 336         RSA_set_method(out->rsa, RSA_get_method(in->rsa));
 337         BN_copy(out->rsa->n, in->rsa->n);
 338         BN_copy(out->rsa->e, in->rsa->e);
 339         priv = RSA_get_app_data(in->rsa);
 340         priv->ref_count++;
 341         RSA_set_app_data(out->rsa, priv);
 342         return;
 343 }
 344
 345 static int
 346 sc_read_pubkey(Key * k, const struct sc_pkcs15_object *cert_obj)
 347 {
 348         int r;
 349         sc_pkcs15_cert_t *cert = NULL;
 350         struct sc_priv_data *priv = NULL;
 351         sc_pkcs15_cert_info_t *cinfo = cert_obj->data;
 352
 353         X509 *x509 = NULL;
 354         EVP_PKEY *pubkey = NULL;
 355         u8 *p;
 356         char *tmp;
 357
 358         debug("sc_read_pubkey() with cert id %02X", cinfo->id.value[0]);
 359         r = sc_pkcs15_read_certificate(p15card, cinfo, &cert);
 360         if (r) {
 361                 logit("Certificate read failed: %s", sc_strerror(r));
 362                 goto err;
 363         }
 364         x509 = X509_new();
 365         if (x509 == NULL) {
 366                 r = -1;
 367                 goto err;
 368         }
 369         p = cert->data;
 370         if (!d2i_X509(&x509, &p, cert->data_len)) {
 371                 logit("Unable to parse X.509 certificate");
 372                 r = -1;
 373                 goto err;
 374         }
 375         sc_pkcs15_free_certificate(cert);
 376         cert = NULL;
 377         pubkey = X509_get_pubkey(x509);
 378         X509_free(x509);
 379         x509 = NULL;
 380         if (pubkey->type != EVP_PKEY_RSA) {
 381                 logit("Public key is of unknown type");
 382                 r = -1;
 383                 goto err;
 384         }
 385         k->rsa = EVP_PKEY_get1_RSA(pubkey);
 386         EVP_PKEY_free(pubkey);
 387
 388         k->rsa->flags |= RSA_FLAG_SIGN_VER;
 389         RSA_set_method(k->rsa, sc_get_rsa_method());
 390         priv = xmalloc(sizeof(struct sc_priv_data));
 391         priv->cert_id = cinfo->id;
 392         priv->ref_count = 1;
 393         RSA_set_app_data(k->rsa, priv);
 394
 395         k->flags = KEY_FLAG_EXT;
 396         tmp = key_fingerprint(k, SSH_FP_MD5, SSH_FP_HEX);
 397         debug("fingerprint %d %s", key_size(k), tmp);
 398         xfree(tmp);
 399
 400         return 0;
 401 err:
 402         if (cert)
 403                 sc_pkcs15_free_certificate(cert);
 404         if (pubkey)
 405                 EVP_PKEY_free(pubkey);
 406         if (x509)
 407                 X509_free(x509);
 408         return r;
 409 }
 410
 411 Key **
 412 sc_get_keys(const char *id, const char *pin)
 413 {
 414         Key *k, **keys;
 415         int i, r, real_count = 0, key_count;
 416         sc_pkcs15_id_t cert_id;
 417         sc_pkcs15_object_t *certs[32];
 418         char *buf = xstrdup(id), *p;
 419
 420         debug("sc_get_keys called: id = %s", id);
 421
 422         if (sc_pin != NULL)
 423                 xfree(sc_pin);
 424         sc_pin = (pin == NULL) ? NULL : xstrdup(pin);
 425
 426         cert_id.len = 0;
 427         if ((p = strchr(buf, ':')) != NULL) {
 428                 *p = 0;
 429                 p++;
 430                 sc_pkcs15_hex_string_to_id(p, &cert_id);
 431         }
 432         r = sscanf(buf, "%d", &sc_reader_id);
 433         xfree(buf);
 434         if (r != 1)
 435                 goto err;
 436         if (p15card == NULL) {
 437                 sc_close();
 438                 r = sc_init();
 439                 if (r) {
 440                         error("Smartcard init failed: %s", sc_strerror(r));
 441                         goto err;
 442                 }
 443         }
 444         if (cert_id.len) {
 445                 r = sc_pkcs15_find_cert_by_id(p15card, &cert_id, &certs[0]);
 446                 if (r < 0)
 447                         goto err;
 448                 key_count = 1;
 449         } else {
 450                 r = sc_pkcs15_get_objects(p15card, SC_PKCS15_TYPE_CERT_X509,
 451                                           certs, 32);
 452                 if (r == 0) {
 453                         logit("No certificates found on smartcard");
 454                         r = -1;
 455                         goto err;
 456                 } else if (r < 0) {
 457                         error("Certificate enumeration failed: %s",
 458                               sc_strerror(r));
 459                         goto err;
 460                 }
 461                 key_count = r;
 462         }
 463         if (key_count > 1024)
 464                 fatal("Too many keys (%u), expected <= 1024", key_count);
 465         keys = xcalloc(key_count * 2 + 1, sizeof(Key *));
 466         for (i = 0; i < key_count; i++) {
 467                 sc_pkcs15_object_t *tmp_obj = NULL;
 468                 cert_id = ((sc_pkcs15_cert_info_t *)(certs[i]->data))->id;
 469                 if (sc_pkcs15_find_prkey_by_id(p15card, &cert_id, &tmp_obj))
 470                         /* skip the public key (certificate) if no
 471                          * corresponding private key is present */
 472                         continue;
 473                 k = key_new(KEY_RSA);
 474                 if (k == NULL)
 475                         break;
 476                 r = sc_read_pubkey(k, certs[i]);
 477                 if (r) {
 478                         error("sc_read_pubkey failed: %s", sc_strerror(r));
 479                         key_free(k);
 480                         continue;
 481                 }
 482                 keys[real_count] = k;
 483                 real_count++;
 484                 k = key_new(KEY_RSA1);
 485                 if (k == NULL)
 486                         break;
 487                 convert_rsa_to_rsa1(keys[real_count-1], k);
 488                 keys[real_count] = k;
 489                 real_count++;
 490         }
 491         keys[real_count] = NULL;
 492
 493         return keys;
 494 err:
 495         sc_close();
 496         return NULL;
 497 }
 498
 499 int
 500 sc_put_key(Key *prv, const char *id)
 501 {
 502         error("key uploading not yet supported");
 503         return -1;
 504 }
 505
 506 char *
 507 sc_get_key_label(Key *key)
 508 {
 509         int r;
 510         const struct sc_priv_data *priv;
 511         struct sc_pkcs15_object *key_obj;
 512
 513         priv = (const struct sc_priv_data *) RSA_get_app_data(key->rsa);
 514         if (priv == NULL || p15card == NULL) {
 515                 logit("SmartCard key not loaded");
 516                 /* internal error => return default label */
 517                 return xstrdup("smartcard key");
 518         }
 519         r = sc_pkcs15_find_prkey_by_id(p15card, &priv->cert_id, &key_obj);
 520         if (r) {
 521                 logit("Unable to find private key from SmartCard: %s",
 522                       sc_strerror(r));
 523                 return xstrdup("smartcard key");
 524         }
 525         if (key_obj == NULL || key_obj->label == NULL)
 526                 /* the optional PKCS#15 label does not exists
 527                  * => return the default label */
 528                 return xstrdup("smartcard key");
 529         return xstrdup(key_obj->label);
 530 }
 531
 532 #endif /* SMARTCARD */