ssh-pkcs11.c revision 226046
1/* $OpenBSD: ssh-pkcs11.c,v 1.6 2010/06/08 21:32:19 markus 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 43struct pkcs11_slotinfo { 44 CK_TOKEN_INFO token; 45 CK_SESSION_HANDLE session; 46 int logged_in; 47}; 48 49struct 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 62TAILQ_HEAD(, pkcs11_provider) pkcs11_providers; 63 64struct 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 73int pkcs11_interactive = 0; 74 75int 76pkcs11_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 */ 89static void 90pkcs11_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 */ 116static void 117pkcs11_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 xfree(p->slotlist); 124 xfree(p->slotinfo); 125 xfree(p); 126 } 127} 128 129/* unregister all providers, keys might still point to the providers */ 130void 131pkcs11_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 */ 143static struct pkcs11_provider * 144pkcs11_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 */ 157int 158pkcs11_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 */ 172static int 173pkcs11_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 if (k11->keyid) 184 xfree(k11->keyid); 185 xfree(k11); 186 } 187 return (rv); 188} 189 190/* find a single 'obj' for given attributes */ 191static int 192pkcs11_find(struct pkcs11_provider *p, CK_ULONG slotidx, CK_ATTRIBUTE *attr, 193 CK_ULONG nattr, CK_OBJECT_HANDLE *obj) 194{ 195 CK_FUNCTION_LIST *f; 196 CK_SESSION_HANDLE session; 197 CK_ULONG nfound = 0; 198 CK_RV rv; 199 int ret = -1; 200 201 f = p->function_list; 202 session = p->slotinfo[slotidx].session; 203 if ((rv = f->C_FindObjectsInit(session, attr, nattr)) != CKR_OK) { 204 error("C_FindObjectsInit failed (nattr %lu): %lu", nattr, rv); 205 return (-1); 206 } 207 if ((rv = f->C_FindObjects(session, obj, 1, &nfound)) != CKR_OK || 208 nfound != 1) { 209 debug("C_FindObjects failed (nfound %lu nattr %lu): %lu", 210 nfound, nattr, rv); 211 } else 212 ret = 0; 213 if ((rv = f->C_FindObjectsFinal(session)) != CKR_OK) 214 error("C_FindObjectsFinal failed: %lu", rv); 215 return (ret); 216} 217 218/* openssl callback doing the actual signing operation */ 219static int 220pkcs11_rsa_private_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa, 221 int padding) 222{ 223 struct pkcs11_key *k11; 224 struct pkcs11_slotinfo *si; 225 CK_FUNCTION_LIST *f; 226 CK_OBJECT_HANDLE obj; 227 CK_ULONG tlen = 0; 228 CK_RV rv; 229 CK_OBJECT_CLASS private_key_class = CKO_PRIVATE_KEY; 230 CK_BBOOL true_val = CK_TRUE; 231 CK_MECHANISM mech = { 232 CKM_RSA_PKCS, NULL_PTR, 0 233 }; 234 CK_ATTRIBUTE key_filter[] = { 235 {CKA_CLASS, NULL, sizeof(private_key_class) }, 236 {CKA_ID, NULL, 0}, 237 {CKA_SIGN, NULL, sizeof(true_val) } 238 }; 239 char *pin, prompt[1024]; 240 int rval = -1; 241 242 /* some compilers complain about non-constant initializer so we 243 use NULL in CK_ATTRIBUTE above and set the values here */ 244 key_filter[0].pValue = &private_key_class; 245 key_filter[2].pValue = &true_val; 246 247 if ((k11 = RSA_get_app_data(rsa)) == NULL) { 248 error("RSA_get_app_data failed for rsa %p", rsa); 249 return (-1); 250 } 251 if (!k11->provider || !k11->provider->valid) { 252 error("no pkcs11 (valid) provider for rsa %p", rsa); 253 return (-1); 254 } 255 f = k11->provider->function_list; 256 si = &k11->provider->slotinfo[k11->slotidx]; 257 if ((si->token.flags & CKF_LOGIN_REQUIRED) && !si->logged_in) { 258 if (!pkcs11_interactive) { 259 error("need pin"); 260 return (-1); 261 } 262 snprintf(prompt, sizeof(prompt), "Enter PIN for '%s': ", 263 si->token.label); 264 pin = read_passphrase(prompt, RP_ALLOW_EOF); 265 if (pin == NULL) 266 return (-1); /* bail out */ 267 if ((rv = f->C_Login(si->session, CKU_USER, pin, strlen(pin))) 268 != CKR_OK) { 269 xfree(pin); 270 error("C_Login failed: %lu", rv); 271 return (-1); 272 } 273 xfree(pin); 274 si->logged_in = 1; 275 } 276 key_filter[1].pValue = k11->keyid; 277 key_filter[1].ulValueLen = k11->keyid_len; 278 /* try to find object w/CKA_SIGN first, retry w/o */ 279 if (pkcs11_find(k11->provider, k11->slotidx, key_filter, 3, &obj) < 0 && 280 pkcs11_find(k11->provider, k11->slotidx, key_filter, 2, &obj) < 0) { 281 error("cannot find private key"); 282 } else if ((rv = f->C_SignInit(si->session, &mech, obj)) != CKR_OK) { 283 error("C_SignInit failed: %lu", rv); 284 } else { 285 /* XXX handle CKR_BUFFER_TOO_SMALL */ 286 tlen = RSA_size(rsa); 287 rv = f->C_Sign(si->session, (CK_BYTE *)from, flen, to, &tlen); 288 if (rv == CKR_OK) 289 rval = tlen; 290 else 291 error("C_Sign failed: %lu", rv); 292 } 293 return (rval); 294} 295 296static int 297pkcs11_rsa_private_decrypt(int flen, const u_char *from, u_char *to, RSA *rsa, 298 int padding) 299{ 300 return (-1); 301} 302 303/* redirect private key operations for rsa key to pkcs11 token */ 304static int 305pkcs11_rsa_wrap(struct pkcs11_provider *provider, CK_ULONG slotidx, 306 CK_ATTRIBUTE *keyid_attrib, RSA *rsa) 307{ 308 struct pkcs11_key *k11; 309 const RSA_METHOD *def = RSA_get_default_method(); 310 311 k11 = xcalloc(1, sizeof(*k11)); 312 k11->provider = provider; 313 provider->refcount++; /* provider referenced by RSA key */ 314 k11->slotidx = slotidx; 315 /* identify key object on smartcard */ 316 k11->keyid_len = keyid_attrib->ulValueLen; 317 k11->keyid = xmalloc(k11->keyid_len); 318 memcpy(k11->keyid, keyid_attrib->pValue, k11->keyid_len); 319 k11->orig_finish = def->finish; 320 memcpy(&k11->rsa_method, def, sizeof(k11->rsa_method)); 321 k11->rsa_method.name = "pkcs11"; 322 k11->rsa_method.rsa_priv_enc = pkcs11_rsa_private_encrypt; 323 k11->rsa_method.rsa_priv_dec = pkcs11_rsa_private_decrypt; 324 k11->rsa_method.finish = pkcs11_rsa_finish; 325 RSA_set_method(rsa, &k11->rsa_method); 326 RSA_set_app_data(rsa, k11); 327 return (0); 328} 329 330/* remove trailing spaces */ 331static void 332rmspace(char *buf, size_t len) 333{ 334 size_t i; 335 336 if (!len) 337 return; 338 for (i = len - 1; i > 0; i--) 339 if (i == len - 1 || buf[i] == ' ') 340 buf[i] = '\0'; 341 else 342 break; 343} 344 345/* 346 * open a pkcs11 session and login if required. 347 * if pin == NULL we delay login until key use 348 */ 349static int 350pkcs11_open_session(struct pkcs11_provider *p, CK_ULONG slotidx, char *pin) 351{ 352 CK_RV rv; 353 CK_FUNCTION_LIST *f; 354 CK_SESSION_HANDLE session; 355 int login_required; 356 357 f = p->function_list; 358 login_required = p->slotinfo[slotidx].token.flags & CKF_LOGIN_REQUIRED; 359 if (pin && login_required && !strlen(pin)) { 360 error("pin required"); 361 return (-1); 362 } 363 if ((rv = f->C_OpenSession(p->slotlist[slotidx], CKF_RW_SESSION| 364 CKF_SERIAL_SESSION, NULL, NULL, &session)) 365 != CKR_OK) { 366 error("C_OpenSession failed: %lu", rv); 367 return (-1); 368 } 369 if (login_required && pin) { 370 if ((rv = f->C_Login(session, CKU_USER, pin, strlen(pin))) 371 != CKR_OK) { 372 error("C_Login failed: %lu", rv); 373 if ((rv = f->C_CloseSession(session)) != CKR_OK) 374 error("C_CloseSession failed: %lu", rv); 375 return (-1); 376 } 377 p->slotinfo[slotidx].logged_in = 1; 378 } 379 p->slotinfo[slotidx].session = session; 380 return (0); 381} 382 383/* 384 * lookup public keys for token in slot identified by slotidx, 385 * add 'wrapped' public keys to the 'keysp' array and increment nkeys. 386 * keysp points to an (possibly empty) array with *nkeys keys. 387 */ 388static int 389pkcs11_fetch_keys(struct pkcs11_provider *p, CK_ULONG slotidx, Key ***keysp, 390 int *nkeys) 391{ 392 Key *key; 393 RSA *rsa; 394 int i; 395 CK_RV rv; 396 CK_OBJECT_HANDLE obj; 397 CK_ULONG nfound; 398 CK_SESSION_HANDLE session; 399 CK_FUNCTION_LIST *f; 400 CK_OBJECT_CLASS pubkey_class = CKO_PUBLIC_KEY; 401 CK_ATTRIBUTE pubkey_filter[] = { 402 { CKA_CLASS, NULL, sizeof(pubkey_class) } 403 }; 404 CK_ATTRIBUTE attribs[] = { 405 { CKA_ID, NULL, 0 }, 406 { CKA_MODULUS, NULL, 0 }, 407 { CKA_PUBLIC_EXPONENT, NULL, 0 } 408 }; 409 410 /* some compilers complain about non-constant initializer so we 411 use NULL in CK_ATTRIBUTE above and set the value here */ 412 pubkey_filter[0].pValue = &pubkey_class; 413 414 f = p->function_list; 415 session = p->slotinfo[slotidx].session; 416 /* setup a filter the looks for public keys */ 417 if ((rv = f->C_FindObjectsInit(session, pubkey_filter, 1)) != CKR_OK) { 418 error("C_FindObjectsInit failed: %lu", rv); 419 return (-1); 420 } 421 while (1) { 422 /* XXX 3 attributes in attribs[] */ 423 for (i = 0; i < 3; i++) { 424 attribs[i].pValue = NULL; 425 attribs[i].ulValueLen = 0; 426 } 427 if ((rv = f->C_FindObjects(session, &obj, 1, &nfound)) != CKR_OK 428 || nfound == 0) 429 break; 430 /* found a key, so figure out size of the attributes */ 431 if ((rv = f->C_GetAttributeValue(session, obj, attribs, 3)) 432 != CKR_OK) { 433 error("C_GetAttributeValue failed: %lu", rv); 434 continue; 435 } 436 /* check that none of the attributes are zero length */ 437 if (attribs[0].ulValueLen == 0 || 438 attribs[1].ulValueLen == 0 || 439 attribs[2].ulValueLen == 0) { 440 continue; 441 } 442 /* allocate buffers for attributes */ 443 for (i = 0; i < 3; i++) 444 attribs[i].pValue = xmalloc(attribs[i].ulValueLen); 445 /* retrieve ID, modulus and public exponent of RSA key */ 446 if ((rv = f->C_GetAttributeValue(session, obj, attribs, 3)) 447 != CKR_OK) { 448 error("C_GetAttributeValue failed: %lu", rv); 449 } else if ((rsa = RSA_new()) == NULL) { 450 error("RSA_new failed"); 451 } else { 452 rsa->n = BN_bin2bn(attribs[1].pValue, 453 attribs[1].ulValueLen, NULL); 454 rsa->e = BN_bin2bn(attribs[2].pValue, 455 attribs[2].ulValueLen, NULL); 456 if (rsa->n && rsa->e && 457 pkcs11_rsa_wrap(p, slotidx, &attribs[0], rsa) == 0) { 458 key = key_new(KEY_UNSPEC); 459 key->rsa = rsa; 460 key->type = KEY_RSA; 461 key->flags |= KEY_FLAG_EXT; 462 /* expand key array and add key */ 463 *keysp = xrealloc(*keysp, *nkeys + 1, 464 sizeof(Key *)); 465 (*keysp)[*nkeys] = key; 466 *nkeys = *nkeys + 1; 467 debug("have %d keys", *nkeys); 468 } else { 469 RSA_free(rsa); 470 } 471 } 472 for (i = 0; i < 3; i++) 473 xfree(attribs[i].pValue); 474 } 475 if ((rv = f->C_FindObjectsFinal(session)) != CKR_OK) 476 error("C_FindObjectsFinal failed: %lu", rv); 477 return (0); 478} 479 480/* register a new provider, fails if provider already exists */ 481int 482pkcs11_add_provider(char *provider_id, char *pin, Key ***keyp) 483{ 484 int nkeys, need_finalize = 0; 485 struct pkcs11_provider *p = NULL; 486 void *handle = NULL; 487 CK_RV (*getfunctionlist)(CK_FUNCTION_LIST **); 488 CK_RV rv; 489 CK_FUNCTION_LIST *f = NULL; 490 CK_TOKEN_INFO *token; 491 CK_ULONG i; 492 493 *keyp = NULL; 494 if (pkcs11_provider_lookup(provider_id) != NULL) { 495 error("provider already registered: %s", provider_id); 496 goto fail; 497 } 498 /* open shared pkcs11-libarary */ 499 if ((handle = dlopen(provider_id, RTLD_NOW)) == NULL) { 500 error("dlopen %s failed: %s", provider_id, dlerror()); 501 goto fail; 502 } 503 if ((getfunctionlist = dlsym(handle, "C_GetFunctionList")) == NULL) { 504 error("dlsym(C_GetFunctionList) failed: %s", dlerror()); 505 goto fail; 506 } 507 p = xcalloc(1, sizeof(*p)); 508 p->name = xstrdup(provider_id); 509 p->handle = handle; 510 /* setup the pkcs11 callbacks */ 511 if ((rv = (*getfunctionlist)(&f)) != CKR_OK) { 512 error("C_GetFunctionList failed: %lu", rv); 513 goto fail; 514 } 515 p->function_list = f; 516 if ((rv = f->C_Initialize(NULL)) != CKR_OK) { 517 error("C_Initialize failed: %lu", rv); 518 goto fail; 519 } 520 need_finalize = 1; 521 if ((rv = f->C_GetInfo(&p->info)) != CKR_OK) { 522 error("C_GetInfo failed: %lu", rv); 523 goto fail; 524 } 525 rmspace(p->info.manufacturerID, sizeof(p->info.manufacturerID)); 526 rmspace(p->info.libraryDescription, sizeof(p->info.libraryDescription)); 527 debug("manufacturerID <%s> cryptokiVersion %d.%d" 528 " libraryDescription <%s> libraryVersion %d.%d", 529 p->info.manufacturerID, 530 p->info.cryptokiVersion.major, 531 p->info.cryptokiVersion.minor, 532 p->info.libraryDescription, 533 p->info.libraryVersion.major, 534 p->info.libraryVersion.minor); 535 if ((rv = f->C_GetSlotList(CK_TRUE, NULL, &p->nslots)) != CKR_OK) { 536 error("C_GetSlotList failed: %lu", rv); 537 goto fail; 538 } 539 if (p->nslots == 0) { 540 error("no slots"); 541 goto fail; 542 } 543 p->slotlist = xcalloc(p->nslots, sizeof(CK_SLOT_ID)); 544 if ((rv = f->C_GetSlotList(CK_TRUE, p->slotlist, &p->nslots)) 545 != CKR_OK) { 546 error("C_GetSlotList failed: %lu", rv); 547 goto fail; 548 } 549 p->slotinfo = xcalloc(p->nslots, sizeof(struct pkcs11_slotinfo)); 550 p->valid = 1; 551 nkeys = 0; 552 for (i = 0; i < p->nslots; i++) { 553 token = &p->slotinfo[i].token; 554 if ((rv = f->C_GetTokenInfo(p->slotlist[i], token)) 555 != CKR_OK) { 556 error("C_GetTokenInfo failed: %lu", rv); 557 continue; 558 } 559 rmspace(token->label, sizeof(token->label)); 560 rmspace(token->manufacturerID, sizeof(token->manufacturerID)); 561 rmspace(token->model, sizeof(token->model)); 562 rmspace(token->serialNumber, sizeof(token->serialNumber)); 563 debug("label <%s> manufacturerID <%s> model <%s> serial <%s>" 564 " flags 0x%lx", 565 token->label, token->manufacturerID, token->model, 566 token->serialNumber, token->flags); 567 /* open session, login with pin and retrieve public keys */ 568 if (pkcs11_open_session(p, i, pin) == 0) 569 pkcs11_fetch_keys(p, i, keyp, &nkeys); 570 } 571 if (nkeys > 0) { 572 TAILQ_INSERT_TAIL(&pkcs11_providers, p, next); 573 p->refcount++; /* add to provider list */ 574 return (nkeys); 575 } 576 error("no keys"); 577 /* don't add the provider, since it does not have any keys */ 578fail: 579 if (need_finalize && (rv = f->C_Finalize(NULL)) != CKR_OK) 580 error("C_Finalize failed: %lu", rv); 581 if (p) { 582 if (p->slotlist) 583 xfree(p->slotlist); 584 if (p->slotinfo) 585 xfree(p->slotinfo); 586 xfree(p); 587 } 588 if (handle) 589 dlclose(handle); 590 return (-1); 591} 592 593#else 594 595int 596pkcs11_init(int interactive) 597{ 598 return (0); 599} 600 601void 602pkcs11_terminate(void) 603{ 604 return; 605} 606 607#endif /* ENABLE_PKCS11 */ 608