1 /* $OpenBSD: ssh-pkcs11.c,v 1.8 2013/07/12 00:20:00 djm Exp $ */ 2 /* 3 * Copyright (c) 2010 Markus Friedl. All rights reserved. 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #include "includes.h" 19 20 #ifdef ENABLE_PKCS11 21 22 #include <sys/types.h> 23 #ifdef HAVE_SYS_TIME_H 24 # include <sys/time.h> 25 #endif 26 #include <stdarg.h> 27 #include <stdio.h> 28 29 #include <string.h> 30 #include <dlfcn.h> 31 32 #include "openbsd-compat/sys-queue.h" 33 34 #define CRYPTOKI_COMPAT 35 #include "pkcs11.h" 36 37 #include "log.h" 38 #include "misc.h" 39 #include "key.h" 40 #include "ssh-pkcs11.h" 41 #include "xmalloc.h" 42 43 struct pkcs11_slotinfo { 44 CK_TOKEN_INFO token; 45 CK_SESSION_HANDLE session; 46 int logged_in; 47 }; 48 49 struct pkcs11_provider { 50 char *name; 51 void *handle; 52 CK_FUNCTION_LIST *function_list; 53 CK_INFO info; 54 CK_ULONG nslots; 55 CK_SLOT_ID *slotlist; 56 struct pkcs11_slotinfo *slotinfo; 57 int valid; 58 int refcount; 59 TAILQ_ENTRY(pkcs11_provider) next; 60 }; 61 62 TAILQ_HEAD(, pkcs11_provider) pkcs11_providers; 63 64 struct pkcs11_key { 65 struct pkcs11_provider *provider; 66 CK_ULONG slotidx; 67 int (*orig_finish)(RSA *rsa); 68 RSA_METHOD rsa_method; 69 char *keyid; 70 int keyid_len; 71 }; 72 73 int pkcs11_interactive = 0; 74 75 int 76 pkcs11_init(int interactive) 77 { 78 pkcs11_interactive = interactive; 79 TAILQ_INIT(&pkcs11_providers); 80 return (0); 81 } 82 83 /* 84 * finalize a provider shared libarary, it's no longer usable. 85 * however, there might still be keys referencing this provider, 86 * so the actuall freeing of memory is handled by pkcs11_provider_unref(). 87 * this is called when a provider gets unregistered. 88 */ 89 static void 90 pkcs11_provider_finalize(struct pkcs11_provider *p) 91 { 92 CK_RV rv; 93 CK_ULONG i; 94 95 debug("pkcs11_provider_finalize: %p refcount %d valid %d", 96 p, p->refcount, p->valid); 97 if (!p->valid) 98 return; 99 for (i = 0; i < p->nslots; i++) { 100 if (p->slotinfo[i].session && 101 (rv = p->function_list->C_CloseSession( 102 p->slotinfo[i].session)) != CKR_OK) 103 error("C_CloseSession failed: %lu", rv); 104 } 105 if ((rv = p->function_list->C_Finalize(NULL)) != CKR_OK) 106 error("C_Finalize failed: %lu", rv); 107 p->valid = 0; 108 p->function_list = NULL; 109 dlclose(p->handle); 110 } 111 112 /* 113 * remove a reference to the provider. 114 * called when a key gets destroyed or when the provider is unregistered. 115 */ 116 static void 117 pkcs11_provider_unref(struct pkcs11_provider *p) 118 { 119 debug("pkcs11_provider_unref: %p refcount %d", p, p->refcount); 120 if (--p->refcount <= 0) { 121 if (p->valid) 122 error("pkcs11_provider_unref: %p still valid", p); 123 free(p->slotlist); 124 free(p->slotinfo); 125 free(p); 126 } 127 } 128 129 /* unregister all providers, keys might still point to the providers */ 130 void 131 pkcs11_terminate(void) 132 { 133 struct pkcs11_provider *p; 134 135 while ((p = TAILQ_FIRST(&pkcs11_providers)) != NULL) { 136 TAILQ_REMOVE(&pkcs11_providers, p, next); 137 pkcs11_provider_finalize(p); 138 pkcs11_provider_unref(p); 139 } 140 } 141 142 /* lookup provider by name */ 143 static struct pkcs11_provider * 144 pkcs11_provider_lookup(char *provider_id) 145 { 146 struct pkcs11_provider *p; 147 148 TAILQ_FOREACH(p, &pkcs11_providers, next) { 149 debug("check %p %s", p, p->name); 150 if (!strcmp(provider_id, p->name)) 151 return (p); 152 } 153 return (NULL); 154 } 155 156 /* unregister provider by name */ 157 int 158 pkcs11_del_provider(char *provider_id) 159 { 160 struct pkcs11_provider *p; 161 162 if ((p = pkcs11_provider_lookup(provider_id)) != NULL) { 163 TAILQ_REMOVE(&pkcs11_providers, p, next); 164 pkcs11_provider_finalize(p); 165 pkcs11_provider_unref(p); 166 return (0); 167 } 168 return (-1); 169 } 170 171 /* openssl callback for freeing an RSA key */ 172 static int 173 pkcs11_rsa_finish(RSA *rsa) 174 { 175 struct pkcs11_key *k11; 176 int rv = -1; 177 178 if ((k11 = RSA_get_app_data(rsa)) != NULL) { 179 if (k11->orig_finish) 180 rv = k11->orig_finish(rsa); 181 if (k11->provider) 182 pkcs11_provider_unref(k11->provider); 183 free(k11->keyid); 184 free(k11); 185 } 186 return (rv); 187 } 188 189 /* find a single 'obj' for given attributes */ 190 static int 191 pkcs11_find(struct pkcs11_provider *p, CK_ULONG slotidx, CK_ATTRIBUTE *attr, 192 CK_ULONG nattr, CK_OBJECT_HANDLE *obj) 193 { 194 CK_FUNCTION_LIST *f; 195 CK_SESSION_HANDLE session; 196 CK_ULONG nfound = 0; 197 CK_RV rv; 198 int ret = -1; 199 200 f = p->function_list; 201 session = p->slotinfo[slotidx].session; 202 if ((rv = f->C_FindObjectsInit(session, attr, nattr)) != CKR_OK) { 203 error("C_FindObjectsInit failed (nattr %lu): %lu", nattr, rv); 204 return (-1); 205 } 206 if ((rv = f->C_FindObjects(session, obj, 1, &nfound)) != CKR_OK || 207 nfound != 1) { 208 debug("C_FindObjects failed (nfound %lu nattr %lu): %lu", 209 nfound, nattr, rv); 210 } else 211 ret = 0; 212 if ((rv = f->C_FindObjectsFinal(session)) != CKR_OK) 213 error("C_FindObjectsFinal failed: %lu", rv); 214 return (ret); 215 } 216 217 /* openssl callback doing the actual signing operation */ 218 static int 219 pkcs11_rsa_private_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa, 220 int padding) 221 { 222 struct pkcs11_key *k11; 223 struct pkcs11_slotinfo *si; 224 CK_FUNCTION_LIST *f; 225 CK_OBJECT_HANDLE obj; 226 CK_ULONG tlen = 0; 227 CK_RV rv; 228 CK_OBJECT_CLASS private_key_class = CKO_PRIVATE_KEY; 229 CK_BBOOL true_val = CK_TRUE; 230 CK_MECHANISM mech = { 231 CKM_RSA_PKCS, NULL_PTR, 0 232 }; 233 CK_ATTRIBUTE key_filter[] = { 234 {CKA_CLASS, NULL, sizeof(private_key_class) }, 235 {CKA_ID, NULL, 0}, 236 {CKA_SIGN, NULL, sizeof(true_val) } 237 }; 238 char *pin, prompt[1024]; 239 int rval = -1; 240 241 /* some compilers complain about non-constant initializer so we 242 use NULL in CK_ATTRIBUTE above and set the values here */ 243 key_filter[0].pValue = &private_key_class; 244 key_filter[2].pValue = &true_val; 245 246 if ((k11 = RSA_get_app_data(rsa)) == NULL) { 247 error("RSA_get_app_data failed for rsa %p", rsa); 248 return (-1); 249 } 250 if (!k11->provider || !k11->provider->valid) { 251 error("no pkcs11 (valid) provider for rsa %p", rsa); 252 return (-1); 253 } 254 f = k11->provider->function_list; 255 si = &k11->provider->slotinfo[k11->slotidx]; 256 if ((si->token.flags & CKF_LOGIN_REQUIRED) && !si->logged_in) { 257 if (!pkcs11_interactive) { 258 error("need pin"); 259 return (-1); 260 } 261 snprintf(prompt, sizeof(prompt), "Enter PIN for '%s': ", 262 si->token.label); 263 pin = read_passphrase(prompt, RP_ALLOW_EOF); 264 if (pin == NULL) 265 return (-1); /* bail out */ 266 if ((rv = f->C_Login(si->session, CKU_USER, 267 (u_char *)pin, strlen(pin))) != CKR_OK) { 268 free(pin); 269 error("C_Login failed: %lu", rv); 270 return (-1); 271 } 272 free(pin); 273 si->logged_in = 1; 274 } 275 key_filter[1].pValue = k11->keyid; 276 key_filter[1].ulValueLen = k11->keyid_len; 277 /* try to find object w/CKA_SIGN first, retry w/o */ 278 if (pkcs11_find(k11->provider, k11->slotidx, key_filter, 3, &obj) < 0 && 279 pkcs11_find(k11->provider, k11->slotidx, key_filter, 2, &obj) < 0) { 280 error("cannot find private key"); 281 } else if ((rv = f->C_SignInit(si->session, &mech, obj)) != CKR_OK) { 282 error("C_SignInit failed: %lu", rv); 283 } else { 284 /* XXX handle CKR_BUFFER_TOO_SMALL */ 285 tlen = RSA_size(rsa); 286 rv = f->C_Sign(si->session, (CK_BYTE *)from, flen, to, &tlen); 287 if (rv == CKR_OK) 288 rval = tlen; 289 else 290 error("C_Sign failed: %lu", rv); 291 } 292 return (rval); 293 } 294 295 static int 296 pkcs11_rsa_private_decrypt(int flen, const u_char *from, u_char *to, RSA *rsa, 297 int padding) 298 { 299 return (-1); 300 } 301 302 /* redirect private key operations for rsa key to pkcs11 token */ 303 static int 304 pkcs11_rsa_wrap(struct pkcs11_provider *provider, CK_ULONG slotidx, 305 CK_ATTRIBUTE *keyid_attrib, RSA *rsa) 306 { 307 struct pkcs11_key *k11; 308 const RSA_METHOD *def = RSA_get_default_method(); 309 310 k11 = xcalloc(1, sizeof(*k11)); 311 k11->provider = provider; 312 provider->refcount++; /* provider referenced by RSA key */ 313 k11->slotidx = slotidx; 314 /* identify key object on smartcard */ 315 k11->keyid_len = keyid_attrib->ulValueLen; 316 k11->keyid = xmalloc(k11->keyid_len); 317 memcpy(k11->keyid, keyid_attrib->pValue, k11->keyid_len); 318 k11->orig_finish = def->finish; 319 memcpy(&k11->rsa_method, def, sizeof(k11->rsa_method)); 320 k11->rsa_method.name = "pkcs11"; 321 k11->rsa_method.rsa_priv_enc = pkcs11_rsa_private_encrypt; 322 k11->rsa_method.rsa_priv_dec = pkcs11_rsa_private_decrypt; 323 k11->rsa_method.finish = pkcs11_rsa_finish; 324 RSA_set_method(rsa, &k11->rsa_method); 325 RSA_set_app_data(rsa, k11); 326 return (0); 327 } 328 329 /* remove trailing spaces */ 330 static void 331 rmspace(u_char *buf, size_t len) 332 { 333 size_t i; 334 335 if (!len) 336 return; 337 for (i = len - 1; i > 0; i--) 338 if (i == len - 1 || buf[i] == ' ') 339 buf[i] = '\0'; 340 else 341 break; 342 } 343 344 /* 345 * open a pkcs11 session and login if required. 346 * if pin == NULL we delay login until key use 347 */ 348 static int 349 pkcs11_open_session(struct pkcs11_provider *p, CK_ULONG slotidx, char *pin) 350 { 351 CK_RV rv; 352 CK_FUNCTION_LIST *f; 353 CK_SESSION_HANDLE session; 354 int login_required; 355 356 f = p->function_list; 357 login_required = p->slotinfo[slotidx].token.flags & CKF_LOGIN_REQUIRED; 358 if (pin && login_required && !strlen(pin)) { 359 error("pin required"); 360 return (-1); 361 } 362 if ((rv = f->C_OpenSession(p->slotlist[slotidx], CKF_RW_SESSION| 363 CKF_SERIAL_SESSION, NULL, NULL, &session)) 364 != CKR_OK) { 365 error("C_OpenSession failed: %lu", rv); 366 return (-1); 367 } 368 if (login_required && pin) { 369 if ((rv = f->C_Login(session, CKU_USER, 370 (u_char *)pin, strlen(pin))) != CKR_OK) { 371 error("C_Login failed: %lu", rv); 372 if ((rv = f->C_CloseSession(session)) != CKR_OK) 373 error("C_CloseSession failed: %lu", rv); 374 return (-1); 375 } 376 p->slotinfo[slotidx].logged_in = 1; 377 } 378 p->slotinfo[slotidx].session = session; 379 return (0); 380 } 381 382 /* 383 * lookup public keys for token in slot identified by slotidx, 384 * add 'wrapped' public keys to the 'keysp' array and increment nkeys. 385 * keysp points to an (possibly empty) array with *nkeys keys. 386 */ 387 static int 388 pkcs11_fetch_keys(struct pkcs11_provider *p, CK_ULONG slotidx, Key ***keysp, 389 int *nkeys) 390 { 391 Key *key; 392 RSA *rsa; 393 int i; 394 CK_RV rv; 395 CK_OBJECT_HANDLE obj; 396 CK_ULONG nfound; 397 CK_SESSION_HANDLE session; 398 CK_FUNCTION_LIST *f; 399 CK_OBJECT_CLASS pubkey_class = CKO_PUBLIC_KEY; 400 CK_ATTRIBUTE pubkey_filter[] = { 401 { CKA_CLASS, NULL, sizeof(pubkey_class) } 402 }; 403 CK_ATTRIBUTE attribs[] = { 404 { CKA_ID, NULL, 0 }, 405 { CKA_MODULUS, NULL, 0 }, 406 { CKA_PUBLIC_EXPONENT, NULL, 0 } 407 }; 408 409 /* some compilers complain about non-constant initializer so we 410 use NULL in CK_ATTRIBUTE above and set the value here */ 411 pubkey_filter[0].pValue = &pubkey_class; 412 413 f = p->function_list; 414 session = p->slotinfo[slotidx].session; 415 /* setup a filter the looks for public keys */ 416 if ((rv = f->C_FindObjectsInit(session, pubkey_filter, 1)) != CKR_OK) { 417 error("C_FindObjectsInit failed: %lu", rv); 418 return (-1); 419 } 420 while (1) { 421 /* XXX 3 attributes in attribs[] */ 422 for (i = 0; i < 3; i++) { 423 attribs[i].pValue = NULL; 424 attribs[i].ulValueLen = 0; 425 } 426 if ((rv = f->C_FindObjects(session, &obj, 1, &nfound)) != CKR_OK 427 || nfound == 0) 428 break; 429 /* found a key, so figure out size of the attributes */ 430 if ((rv = f->C_GetAttributeValue(session, obj, attribs, 3)) 431 != CKR_OK) { 432 error("C_GetAttributeValue failed: %lu", rv); 433 continue; 434 } 435 /* check that none of the attributes are zero length */ 436 if (attribs[0].ulValueLen == 0 || 437 attribs[1].ulValueLen == 0 || 438 attribs[2].ulValueLen == 0) { 439 continue; 440 } 441 /* allocate buffers for attributes */ 442 for (i = 0; i < 3; i++) 443 attribs[i].pValue = xmalloc(attribs[i].ulValueLen); 444 /* retrieve ID, modulus and public exponent of RSA key */ 445 if ((rv = f->C_GetAttributeValue(session, obj, attribs, 3)) 446 != CKR_OK) { 447 error("C_GetAttributeValue failed: %lu", rv); 448 } else if ((rsa = RSA_new()) == NULL) { 449 error("RSA_new failed"); 450 } else { 451 rsa->n = BN_bin2bn(attribs[1].pValue, 452 attribs[1].ulValueLen, NULL); 453 rsa->e = BN_bin2bn(attribs[2].pValue, 454 attribs[2].ulValueLen, NULL); 455 if (rsa->n && rsa->e && 456 pkcs11_rsa_wrap(p, slotidx, &attribs[0], rsa) == 0) { 457 key = key_new(KEY_UNSPEC); 458 key->rsa = rsa; 459 key->type = KEY_RSA; 460 key->flags |= KEY_FLAG_EXT; 461 /* expand key array and add key */ 462 *keysp = xrealloc(*keysp, *nkeys + 1, 463 sizeof(Key *)); 464 (*keysp)[*nkeys] = key; 465 *nkeys = *nkeys + 1; 466 debug("have %d keys", *nkeys); 467 } else { 468 RSA_free(rsa); 469 } 470 } 471 for (i = 0; i < 3; i++) 472 free(attribs[i].pValue); 473 } 474 if ((rv = f->C_FindObjectsFinal(session)) != CKR_OK) 475 error("C_FindObjectsFinal failed: %lu", rv); 476 return (0); 477 } 478 479 /* register a new provider, fails if provider already exists */ 480 int 481 pkcs11_add_provider(char *provider_id, char *pin, Key ***keyp) 482 { 483 int nkeys, need_finalize = 0; 484 struct pkcs11_provider *p = NULL; 485 void *handle = NULL; 486 CK_RV (*getfunctionlist)(CK_FUNCTION_LIST **); 487 CK_RV rv; 488 CK_FUNCTION_LIST *f = NULL; 489 CK_TOKEN_INFO *token; 490 CK_ULONG i; 491 492 *keyp = NULL; 493 if (pkcs11_provider_lookup(provider_id) != NULL) { 494 error("provider already registered: %s", provider_id); 495 goto fail; 496 } 497 /* open shared pkcs11-libarary */ 498 if ((handle = dlopen(provider_id, RTLD_NOW)) == NULL) { 499 error("dlopen %s failed: %s", provider_id, dlerror()); 500 goto fail; 501 } 502 if ((getfunctionlist = dlsym(handle, "C_GetFunctionList")) == NULL) { 503 error("dlsym(C_GetFunctionList) failed: %s", dlerror()); 504 goto fail; 505 } 506 p = xcalloc(1, sizeof(*p)); 507 p->name = xstrdup(provider_id); 508 p->handle = handle; 509 /* setup the pkcs11 callbacks */ 510 if ((rv = (*getfunctionlist)(&f)) != CKR_OK) { 511 error("C_GetFunctionList failed: %lu", rv); 512 goto fail; 513 } 514 p->function_list = f; 515 if ((rv = f->C_Initialize(NULL)) != CKR_OK) { 516 error("C_Initialize failed: %lu", rv); 517 goto fail; 518 } 519 need_finalize = 1; 520 if ((rv = f->C_GetInfo(&p->info)) != CKR_OK) { 521 error("C_GetInfo failed: %lu", rv); 522 goto fail; 523 } 524 rmspace(p->info.manufacturerID, sizeof(p->info.manufacturerID)); 525 rmspace(p->info.libraryDescription, sizeof(p->info.libraryDescription)); 526 debug("manufacturerID <%s> cryptokiVersion %d.%d" 527 " libraryDescription <%s> libraryVersion %d.%d", 528 p->info.manufacturerID, 529 p->info.cryptokiVersion.major, 530 p->info.cryptokiVersion.minor, 531 p->info.libraryDescription, 532 p->info.libraryVersion.major, 533 p->info.libraryVersion.minor); 534 if ((rv = f->C_GetSlotList(CK_TRUE, NULL, &p->nslots)) != CKR_OK) { 535 error("C_GetSlotList failed: %lu", rv); 536 goto fail; 537 } 538 if (p->nslots == 0) { 539 error("no slots"); 540 goto fail; 541 } 542 p->slotlist = xcalloc(p->nslots, sizeof(CK_SLOT_ID)); 543 if ((rv = f->C_GetSlotList(CK_TRUE, p->slotlist, &p->nslots)) 544 != CKR_OK) { 545 error("C_GetSlotList failed: %lu", rv); 546 goto fail; 547 } 548 p->slotinfo = xcalloc(p->nslots, sizeof(struct pkcs11_slotinfo)); 549 p->valid = 1; 550 nkeys = 0; 551 for (i = 0; i < p->nslots; i++) { 552 token = &p->slotinfo[i].token; 553 if ((rv = f->C_GetTokenInfo(p->slotlist[i], token)) 554 != CKR_OK) { 555 error("C_GetTokenInfo failed: %lu", rv); 556 continue; 557 } 558 rmspace(token->label, sizeof(token->label)); 559 rmspace(token->manufacturerID, sizeof(token->manufacturerID)); 560 rmspace(token->model, sizeof(token->model)); 561 rmspace(token->serialNumber, sizeof(token->serialNumber)); 562 debug("label <%s> manufacturerID <%s> model <%s> serial <%s>" 563 " flags 0x%lx", 564 token->label, token->manufacturerID, token->model, 565 token->serialNumber, token->flags); 566 /* open session, login with pin and retrieve public keys */ 567 if (pkcs11_open_session(p, i, pin) == 0) 568 pkcs11_fetch_keys(p, i, keyp, &nkeys); 569 } 570 if (nkeys > 0) { 571 TAILQ_INSERT_TAIL(&pkcs11_providers, p, next); 572 p->refcount++; /* add to provider list */ 573 return (nkeys); 574 } 575 error("no keys"); 576 /* don't add the provider, since it does not have any keys */ 577 fail: 578 if (need_finalize && (rv = f->C_Finalize(NULL)) != CKR_OK) 579 error("C_Finalize failed: %lu", rv); 580 if (p) { 581 free(p->slotlist); 582 free(p->slotinfo); 583 free(p); 584 } 585 if (handle) 586 dlclose(handle); 587 return (-1); 588 } 589 590 #else 591 592 int 593 pkcs11_init(int interactive) 594 { 595 return (0); 596 } 597 598 void 599 pkcs11_terminate(void) 600 { 601 return; 602 } 603 604 #endif /* ENABLE_PKCS11 */ 605