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
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
pkcs11_init(int interactive)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
pkcs11_provider_finalize(struct pkcs11_provider * p)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
pkcs11_provider_unref(struct pkcs11_provider * p)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 xfree(p->slotlist);
124 xfree(p->slotinfo);
125 xfree(p);
126 }
127 }
128
129 /* unregister all providers, keys might still point to the providers */
130 void
pkcs11_terminate(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 *
pkcs11_provider_lookup(char * provider_id)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
pkcs11_del_provider(char * provider_id)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
pkcs11_rsa_finish(RSA * rsa)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 if (k11->keyid)
184 xfree(k11->keyid);
185 xfree(k11);
186 }
187 return (rv);
188 }
189
190 /* find a single 'obj' for given attributes */
191 static int
pkcs11_find(struct pkcs11_provider * p,CK_ULONG slotidx,CK_ATTRIBUTE * attr,CK_ULONG nattr,CK_OBJECT_HANDLE * obj)192 pkcs11_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 */
219 static int
pkcs11_rsa_private_encrypt(int flen,const u_char * from,u_char * to,RSA * rsa,int padding)220 pkcs11_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
296 static int
pkcs11_rsa_private_decrypt(int flen,const u_char * from,u_char * to,RSA * rsa,int padding)297 pkcs11_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 */
304 static int
pkcs11_rsa_wrap(struct pkcs11_provider * provider,CK_ULONG slotidx,CK_ATTRIBUTE * keyid_attrib,RSA * rsa)305 pkcs11_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 */
331 static void
rmspace(char * buf,size_t len)332 rmspace(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 */
349 static int
pkcs11_open_session(struct pkcs11_provider * p,CK_ULONG slotidx,char * pin)350 pkcs11_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 */
388 static int
pkcs11_fetch_keys(struct pkcs11_provider * p,CK_ULONG slotidx,Key *** keysp,int * nkeys)389 pkcs11_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 */
481 int
pkcs11_add_provider(char * provider_id,char * pin,Key *** keyp)482 pkcs11_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 */
578 fail:
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
595 int
pkcs11_init(int interactive)596 pkcs11_init(int interactive)
597 {
598 return (0);
599 }
600
601 void
pkcs11_terminate(void)602 pkcs11_terminate(void)
603 {
604 return;
605 }
606
607 #endif /* ENABLE_PKCS11 */
608