1 /* $OpenBSD: ssh-pkcs11-client.c,v 1.20 2024/08/15 00:51:51 djm Exp $ */
2 /*
3 * Copyright (c) 2010 Markus Friedl. All rights reserved.
4 * Copyright (c) 2014 Pedro Martelletto. All rights reserved.
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #include "includes.h"
20
21 #ifdef ENABLE_PKCS11
22
23 #include <sys/types.h>
24 #ifdef HAVE_SYS_TIME_H
25 # include <sys/time.h>
26 #endif
27 #include <sys/socket.h>
28
29 #include <stdarg.h>
30 #include <string.h>
31 #include <unistd.h>
32 #include <errno.h>
33 #include <limits.h>
34
35 #include <openssl/ecdsa.h>
36 #include <openssl/rsa.h>
37
38 #include "pathnames.h"
39 #include "xmalloc.h"
40 #include "sshbuf.h"
41 #include "log.h"
42 #include "misc.h"
43 #include "sshkey.h"
44 #include "authfd.h"
45 #include "atomicio.h"
46 #include "ssh-pkcs11.h"
47 #include "ssherr.h"
48
49 #include "openbsd-compat/openssl-compat.h"
50
51 #if !defined(OPENSSL_HAS_ECC) || !defined(HAVE_EC_KEY_METHOD_NEW)
52 #define EC_KEY_METHOD void
53 #define EC_KEY void
54 #endif
55
56 /* borrows code from sftp-server and ssh-agent */
57
58 /*
59 * Maintain a list of ssh-pkcs11-helper subprocesses. These may be looked up
60 * by provider path or their unique EC/RSA METHOD pointers.
61 */
62 struct helper {
63 char *path;
64 pid_t pid;
65 int fd;
66 RSA_METHOD *rsa_meth;
67 EC_KEY_METHOD *ec_meth;
68 int (*rsa_finish)(RSA *rsa);
69 void (*ec_finish)(EC_KEY *key);
70 size_t nrsa, nec; /* number of active keys of each type */
71 };
72 static struct helper **helpers;
73 static size_t nhelpers;
74
75 static struct helper *
helper_by_provider(const char * path)76 helper_by_provider(const char *path)
77 {
78 size_t i;
79
80 for (i = 0; i < nhelpers; i++) {
81 if (helpers[i] == NULL || helpers[i]->path == NULL ||
82 helpers[i]->fd == -1)
83 continue;
84 if (strcmp(helpers[i]->path, path) == 0)
85 return helpers[i];
86 }
87 return NULL;
88 }
89
90 static struct helper *
helper_by_rsa(const RSA * rsa)91 helper_by_rsa(const RSA *rsa)
92 {
93 size_t i;
94 const RSA_METHOD *meth;
95
96 if ((meth = RSA_get_method(rsa)) == NULL)
97 return NULL;
98 for (i = 0; i < nhelpers; i++) {
99 if (helpers[i] != NULL && helpers[i]->rsa_meth == meth)
100 return helpers[i];
101 }
102 return NULL;
103
104 }
105
106 #if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
107 static struct helper *
helper_by_ec(const EC_KEY * ec)108 helper_by_ec(const EC_KEY *ec)
109 {
110 size_t i;
111 const EC_KEY_METHOD *meth;
112
113 if ((meth = EC_KEY_get_method(ec)) == NULL)
114 return NULL;
115 for (i = 0; i < nhelpers; i++) {
116 if (helpers[i] != NULL && helpers[i]->ec_meth == meth)
117 return helpers[i];
118 }
119 return NULL;
120
121 }
122 #endif /* defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW) */
123
124 static void
helper_free(struct helper * helper)125 helper_free(struct helper *helper)
126 {
127 size_t i;
128 int found = 0;
129
130 if (helper == NULL)
131 return;
132 if (helper->path == NULL || helper->ec_meth == NULL ||
133 helper->rsa_meth == NULL)
134 fatal_f("inconsistent helper");
135 debug3_f("free helper for provider %s", helper->path);
136 for (i = 0; i < nhelpers; i++) {
137 if (helpers[i] == helper) {
138 if (found)
139 fatal_f("helper recorded more than once");
140 found = 1;
141 }
142 else if (found)
143 helpers[i - 1] = helpers[i];
144 }
145 if (found) {
146 helpers = xrecallocarray(helpers, nhelpers,
147 nhelpers - 1, sizeof(*helpers));
148 nhelpers--;
149 }
150 free(helper->path);
151 #if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
152 EC_KEY_METHOD_free(helper->ec_meth);
153 #endif
154 RSA_meth_free(helper->rsa_meth);
155 free(helper);
156 }
157
158 static void
helper_terminate(struct helper * helper)159 helper_terminate(struct helper *helper)
160 {
161 if (helper == NULL) {
162 return;
163 } else if (helper->fd == -1) {
164 debug3_f("already terminated");
165 } else {
166 debug3_f("terminating helper for %s; "
167 "remaining %zu RSA %zu ECDSA",
168 helper->path, helper->nrsa, helper->nec);
169 close(helper->fd);
170 /* XXX waitpid() */
171 helper->fd = -1;
172 helper->pid = -1;
173 }
174 /*
175 * Don't delete the helper entry until there are no remaining keys
176 * that reference it. Otherwise, any signing operation would call
177 * a free'd METHOD pointer and that would be bad.
178 */
179 if (helper->nrsa == 0 && helper->nec == 0)
180 helper_free(helper);
181 }
182
183 static void
send_msg(int fd,struct sshbuf * m)184 send_msg(int fd, struct sshbuf *m)
185 {
186 u_char buf[4];
187 size_t mlen = sshbuf_len(m);
188 int r;
189
190 if (fd == -1)
191 return;
192 POKE_U32(buf, mlen);
193 if (atomicio(vwrite, fd, buf, 4) != 4 ||
194 atomicio(vwrite, fd, sshbuf_mutable_ptr(m),
195 sshbuf_len(m)) != sshbuf_len(m))
196 error("write to helper failed");
197 if ((r = sshbuf_consume(m, mlen)) != 0)
198 fatal_fr(r, "consume");
199 }
200
201 static int
recv_msg(int fd,struct sshbuf * m)202 recv_msg(int fd, struct sshbuf *m)
203 {
204 u_int l, len;
205 u_char c, buf[1024];
206 int r;
207
208 sshbuf_reset(m);
209 if (fd == -1)
210 return 0; /* XXX */
211 if ((len = atomicio(read, fd, buf, 4)) != 4) {
212 error("read from helper failed: %u", len);
213 return (0); /* XXX */
214 }
215 len = PEEK_U32(buf);
216 if (len > 256 * 1024)
217 fatal("response too long: %u", len);
218 /* read len bytes into m */
219 while (len > 0) {
220 l = len;
221 if (l > sizeof(buf))
222 l = sizeof(buf);
223 if (atomicio(read, fd, buf, l) != l) {
224 error("response from helper failed.");
225 return (0); /* XXX */
226 }
227 if ((r = sshbuf_put(m, buf, l)) != 0)
228 fatal_fr(r, "sshbuf_put");
229 len -= l;
230 }
231 if ((r = sshbuf_get_u8(m, &c)) != 0)
232 fatal_fr(r, "parse type");
233 return c;
234 }
235
236 int
pkcs11_init(int interactive)237 pkcs11_init(int interactive)
238 {
239 return 0;
240 }
241
242 void
pkcs11_terminate(void)243 pkcs11_terminate(void)
244 {
245 size_t i;
246
247 debug3_f("terminating %zu helpers", nhelpers);
248 for (i = 0; i < nhelpers; i++)
249 helper_terminate(helpers[i]);
250 }
251
252 static int
rsa_encrypt(int flen,const u_char * from,u_char * to,RSA * rsa,int padding)253 rsa_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa, int padding)
254 {
255 struct sshkey *key = NULL;
256 struct sshbuf *msg = NULL;
257 u_char *blob = NULL, *signature = NULL;
258 size_t blen, slen = 0;
259 int r, ret = -1;
260 struct helper *helper;
261
262 if ((helper = helper_by_rsa(rsa)) == NULL || helper->fd == -1)
263 fatal_f("no helper for PKCS11 key");
264 debug3_f("signing with PKCS11 provider %s", helper->path);
265 if (padding != RSA_PKCS1_PADDING)
266 goto fail;
267 if ((key = sshkey_new(KEY_UNSPEC)) == NULL) {
268 error_f("sshkey_new failed");
269 goto fail;
270 }
271 if ((key->pkey = EVP_PKEY_new()) == NULL ||
272 EVP_PKEY_set1_RSA(key->pkey, rsa) != 1) {
273 error_f("pkey setup failed");
274 goto fail;
275 }
276
277 key->type = KEY_RSA;
278 if ((r = sshkey_to_blob(key, &blob, &blen)) != 0) {
279 error_fr(r, "encode key");
280 goto fail;
281 }
282 if ((msg = sshbuf_new()) == NULL)
283 fatal_f("sshbuf_new failed");
284 if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 ||
285 (r = sshbuf_put_string(msg, blob, blen)) != 0 ||
286 (r = sshbuf_put_string(msg, from, flen)) != 0 ||
287 (r = sshbuf_put_u32(msg, 0)) != 0)
288 fatal_fr(r, "compose");
289 send_msg(helper->fd, msg);
290 sshbuf_reset(msg);
291
292 if (recv_msg(helper->fd, msg) == SSH2_AGENT_SIGN_RESPONSE) {
293 if ((r = sshbuf_get_string(msg, &signature, &slen)) != 0)
294 fatal_fr(r, "parse");
295 if (slen <= (size_t)RSA_size(rsa)) {
296 memcpy(to, signature, slen);
297 ret = slen;
298 }
299 free(signature);
300 }
301 fail:
302 free(blob);
303 sshkey_free(key);
304 sshbuf_free(msg);
305 return (ret);
306 }
307
308 static int
rsa_finish(RSA * rsa)309 rsa_finish(RSA *rsa)
310 {
311 struct helper *helper;
312
313 if ((helper = helper_by_rsa(rsa)) == NULL)
314 fatal_f("no helper for PKCS11 key");
315 debug3_f("free PKCS11 RSA key for provider %s", helper->path);
316 if (helper->rsa_finish != NULL)
317 helper->rsa_finish(rsa);
318 if (helper->nrsa == 0)
319 fatal_f("RSA refcount error");
320 helper->nrsa--;
321 debug3_f("provider %s remaining keys: %zu RSA %zu ECDSA",
322 helper->path, helper->nrsa, helper->nec);
323 if (helper->nrsa == 0 && helper->nec == 0)
324 helper_terminate(helper);
325 return 1;
326 }
327
328 #if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
329 static ECDSA_SIG *
ecdsa_do_sign(const unsigned char * dgst,int dgst_len,const BIGNUM * inv,const BIGNUM * rp,EC_KEY * ec)330 ecdsa_do_sign(const unsigned char *dgst, int dgst_len, const BIGNUM *inv,
331 const BIGNUM *rp, EC_KEY *ec)
332 {
333 struct sshkey *key = NULL;
334 struct sshbuf *msg = NULL;
335 ECDSA_SIG *ret = NULL;
336 const u_char *cp;
337 u_char *blob = NULL, *signature = NULL;
338 size_t blen, slen = 0;
339 int r, nid;
340 struct helper *helper;
341
342 if ((helper = helper_by_ec(ec)) == NULL || helper->fd == -1)
343 fatal_f("no helper for PKCS11 key");
344 debug3_f("signing with PKCS11 provider %s", helper->path);
345
346 if ((key = sshkey_new(KEY_UNSPEC)) == NULL) {
347 error_f("sshkey_new failed");
348 goto fail;
349 }
350 if ((key->pkey = EVP_PKEY_new()) == NULL ||
351 EVP_PKEY_set1_EC_KEY(key->pkey, ec) != 1) {
352 error("pkey setup failed");
353 goto fail;
354 }
355 if ((nid = sshkey_ecdsa_pkey_to_nid(key->pkey)) < 0) {
356 error("couldn't get curve nid");
357 goto fail;
358 }
359 key->ecdsa_nid = nid;
360 key->type = KEY_ECDSA;
361
362 if ((r = sshkey_to_blob(key, &blob, &blen)) != 0) {
363 error_fr(r, "encode key");
364 goto fail;
365 }
366 if ((msg = sshbuf_new()) == NULL)
367 fatal_f("sshbuf_new failed");
368 if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 ||
369 (r = sshbuf_put_string(msg, blob, blen)) != 0 ||
370 (r = sshbuf_put_string(msg, dgst, dgst_len)) != 0 ||
371 (r = sshbuf_put_u32(msg, 0)) != 0)
372 fatal_fr(r, "compose");
373 send_msg(helper->fd, msg);
374 sshbuf_reset(msg);
375
376 if (recv_msg(helper->fd, msg) == SSH2_AGENT_SIGN_RESPONSE) {
377 if ((r = sshbuf_get_string(msg, &signature, &slen)) != 0)
378 fatal_fr(r, "parse");
379 cp = signature;
380 ret = d2i_ECDSA_SIG(NULL, &cp, slen);
381 free(signature);
382 }
383
384 fail:
385 free(blob);
386 sshkey_free(key);
387 sshbuf_free(msg);
388 return (ret);
389 }
390
391 static void
ecdsa_do_finish(EC_KEY * ec)392 ecdsa_do_finish(EC_KEY *ec)
393 {
394 struct helper *helper;
395
396 if ((helper = helper_by_ec(ec)) == NULL)
397 fatal_f("no helper for PKCS11 key");
398 debug3_f("free PKCS11 ECDSA key for provider %s", helper->path);
399 if (helper->ec_finish != NULL)
400 helper->ec_finish(ec);
401 if (helper->nec == 0)
402 fatal_f("ECDSA refcount error");
403 helper->nec--;
404 debug3_f("provider %s remaining keys: %zu RSA %zu ECDSA",
405 helper->path, helper->nrsa, helper->nec);
406 if (helper->nrsa == 0 && helper->nec == 0)
407 helper_terminate(helper);
408 }
409 #endif /* defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW) */
410
411 /* redirect private key crypto operations to the ssh-pkcs11-helper */
412 static void
wrap_key(struct helper * helper,struct sshkey * k)413 wrap_key(struct helper *helper, struct sshkey *k)
414 {
415 RSA *rsa = NULL;
416 EC_KEY *ecdsa = NULL;
417
418 debug3_f("wrap %s for provider %s", sshkey_type(k), helper->path);
419 if (k->type == KEY_RSA) {
420 if ((rsa = EVP_PKEY_get1_RSA(k->pkey)) == NULL)
421 fatal_f("no RSA key");
422 if (RSA_set_method(rsa, helper->rsa_meth) != 1)
423 fatal_f("RSA_set_method failed");
424 if (helper->nrsa++ >= INT_MAX)
425 fatal_f("RSA refcount error");
426 if (EVP_PKEY_set1_RSA(k->pkey, rsa) != 1)
427 fatal_f("EVP_PKEY_set1_RSA failed");
428 RSA_free(rsa);
429 #if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
430 } else if (k->type == KEY_ECDSA) {
431 if ((ecdsa = EVP_PKEY_get1_EC_KEY(k->pkey)) == NULL)
432 fatal_f("no ECDSA key");
433 if (EC_KEY_set_method(ecdsa, helper->ec_meth) != 1)
434 fatal_f("EC_KEY_set_method failed");
435 if (helper->nec++ >= INT_MAX)
436 fatal_f("EC refcount error");
437 if (EVP_PKEY_set1_EC_KEY(k->pkey, ecdsa) != 1)
438 fatal_f("EVP_PKEY_set1_EC_KEY failed");
439 EC_KEY_free(ecdsa);
440 #endif
441 } else
442 fatal_f("unknown key type");
443 k->flags |= SSHKEY_FLAG_EXT;
444 debug3_f("provider %s remaining keys: %zu RSA %zu ECDSA",
445 helper->path, helper->nrsa, helper->nec);
446 }
447
448 /*
449 * Make a private PKCS#11-backed certificate by grafting a previously-loaded
450 * PKCS#11 private key and a public certificate key.
451 */
452 int
pkcs11_make_cert(const struct sshkey * priv,const struct sshkey * certpub,struct sshkey ** certprivp)453 pkcs11_make_cert(const struct sshkey *priv,
454 const struct sshkey *certpub, struct sshkey **certprivp)
455 {
456 struct helper *helper = NULL;
457 struct sshkey *ret;
458 int r;
459 RSA *rsa_priv = NULL, *rsa_cert = NULL;
460 #if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
461 EC_KEY *ec_priv = NULL, *ec_cert = NULL;
462 #endif
463
464 debug3_f("private key type %s cert type %s", sshkey_type(priv),
465 sshkey_type(certpub));
466 *certprivp = NULL;
467 if (!sshkey_is_cert(certpub) || sshkey_is_cert(priv) ||
468 !sshkey_equal_public(priv, certpub)) {
469 error_f("private key %s doesn't match cert %s",
470 sshkey_type(priv), sshkey_type(certpub));
471 return SSH_ERR_INVALID_ARGUMENT;
472 }
473 *certprivp = NULL;
474 if (priv->type == KEY_RSA) {
475 if ((rsa_priv = EVP_PKEY_get1_RSA(priv->pkey)) == NULL)
476 fatal_f("no RSA pkey");
477 if ((helper = helper_by_rsa(rsa_priv)) == NULL ||
478 helper->fd == -1)
479 fatal_f("no helper for PKCS11 RSA key");
480 if ((r = sshkey_from_private(priv, &ret)) != 0)
481 fatal_fr(r, "copy key");
482 if ((rsa_cert = EVP_PKEY_get1_RSA(ret->pkey)) == NULL)
483 fatal_f("no RSA cert pkey");
484 if (RSA_set_method(rsa_cert, helper->rsa_meth) != 1)
485 fatal_f("RSA_set_method failed");
486 if (helper->nrsa++ >= INT_MAX)
487 fatal_f("RSA refcount error");
488 if (EVP_PKEY_set1_RSA(ret->pkey, rsa_cert) != 1)
489 fatal_f("EVP_PKEY_set1_RSA failed");
490 RSA_free(rsa_priv);
491 RSA_free(rsa_cert);
492 #if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
493 } else if (priv->type == KEY_ECDSA) {
494 if ((ec_priv = EVP_PKEY_get1_EC_KEY(priv->pkey)) == NULL)
495 fatal_f("no EC pkey");
496 if ((helper = helper_by_ec(ec_priv)) == NULL ||
497 helper->fd == -1)
498 fatal_f("no helper for PKCS11 EC key");
499 if ((r = sshkey_from_private(priv, &ret)) != 0)
500 fatal_fr(r, "copy key");
501 if ((ec_cert = EVP_PKEY_get1_EC_KEY(ret->pkey)) == NULL)
502 fatal_f("no EC cert pkey");
503 if (EC_KEY_set_method(ec_cert, helper->ec_meth) != 1)
504 fatal_f("EC_KEY_set_method failed");
505 if (helper->nec++ >= INT_MAX)
506 fatal_f("EC refcount error");
507 if (EVP_PKEY_set1_EC_KEY(ret->pkey, ec_cert) != 1)
508 fatal_f("EVP_PKEY_set1_EC_KEY failed");
509 EC_KEY_free(ec_priv);
510 EC_KEY_free(ec_cert);
511 #endif
512 } else
513 fatal_f("unknown key type %s", sshkey_type(priv));
514
515 ret->flags |= SSHKEY_FLAG_EXT;
516 if ((r = sshkey_to_certified(ret)) != 0 ||
517 (r = sshkey_cert_copy(certpub, ret)) != 0)
518 fatal_fr(r, "graft certificate");
519 debug3_f("provider %s remaining keys: %zu RSA %zu ECDSA",
520 helper->path, helper->nrsa, helper->nec);
521 /* success */
522 *certprivp = ret;
523 return 0;
524 }
525
526 static int
pkcs11_start_helper_methods(struct helper * helper)527 pkcs11_start_helper_methods(struct helper *helper)
528 {
529 RSA_METHOD *rsa_meth = NULL;
530 EC_KEY_METHOD *ec_meth = NULL;
531 #if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
532 int (*ec_init)(EC_KEY *key);
533 int (*ec_copy)(EC_KEY *dest, const EC_KEY *src);
534 int (*ec_set_group)(EC_KEY *key, const EC_GROUP *grp);
535 int (*ec_set_private)(EC_KEY *key, const BIGNUM *priv_key);
536 int (*ec_set_public)(EC_KEY *key, const EC_POINT *pub_key);
537 int (*ec_sign)(int, const unsigned char *, int, unsigned char *,
538 unsigned int *, const BIGNUM *, const BIGNUM *, EC_KEY *) = NULL;
539
540 if ((ec_meth = EC_KEY_METHOD_new(EC_KEY_OpenSSL())) == NULL)
541 return -1;
542 EC_KEY_METHOD_get_sign(ec_meth, &ec_sign, NULL, NULL);
543 EC_KEY_METHOD_set_sign(ec_meth, ec_sign, NULL, ecdsa_do_sign);
544 EC_KEY_METHOD_get_init(ec_meth, &ec_init, &helper->ec_finish,
545 &ec_copy, &ec_set_group, &ec_set_private, &ec_set_public);
546 EC_KEY_METHOD_set_init(ec_meth, ec_init, ecdsa_do_finish,
547 ec_copy, ec_set_group, ec_set_private, ec_set_public);
548 #endif /* defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW) */
549
550 if ((rsa_meth = RSA_meth_dup(RSA_get_default_method())) == NULL)
551 fatal_f("RSA_meth_dup failed");
552 helper->rsa_finish = RSA_meth_get_finish(rsa_meth);
553 if (!RSA_meth_set1_name(rsa_meth, "ssh-pkcs11-helper") ||
554 !RSA_meth_set_priv_enc(rsa_meth, rsa_encrypt) ||
555 !RSA_meth_set_finish(rsa_meth, rsa_finish))
556 fatal_f("failed to prepare method");
557
558 helper->ec_meth = ec_meth;
559 helper->rsa_meth = rsa_meth;
560 return 0;
561 }
562
563 static struct helper *
pkcs11_start_helper(const char * path)564 pkcs11_start_helper(const char *path)
565 {
566 int pair[2];
567 char *prog, *verbosity = NULL;
568 struct helper *helper;
569 pid_t pid;
570
571 if (nhelpers >= INT_MAX)
572 fatal_f("too many helpers");
573 debug3_f("start helper for %s", path);
574 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) {
575 error_f("socketpair: %s", strerror(errno));
576 return NULL;
577 }
578 helper = xcalloc(1, sizeof(*helper));
579 if (pkcs11_start_helper_methods(helper) == -1) {
580 error_f("pkcs11_start_helper_methods failed");
581 goto fail;
582 }
583 if ((pid = fork()) == -1) {
584 error_f("fork: %s", strerror(errno));
585 fail:
586 close(pair[0]);
587 close(pair[1]);
588 RSA_meth_free(helper->rsa_meth);
589 #if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
590 EC_KEY_METHOD_free(helper->ec_meth);
591 #endif
592 free(helper);
593 return NULL;
594 } else if (pid == 0) {
595 if ((dup2(pair[1], STDIN_FILENO) == -1) ||
596 (dup2(pair[1], STDOUT_FILENO) == -1)) {
597 fprintf(stderr, "dup2: %s\n", strerror(errno));
598 _exit(1);
599 }
600 close(pair[0]);
601 close(pair[1]);
602 prog = getenv("SSH_PKCS11_HELPER");
603 if (prog == NULL || strlen(prog) == 0)
604 prog = _PATH_SSH_PKCS11_HELPER;
605 if (log_level_get() >= SYSLOG_LEVEL_DEBUG1)
606 verbosity = "-vvv";
607 debug_f("starting %s %s", prog,
608 verbosity == NULL ? "" : verbosity);
609 execlp(prog, prog, verbosity, (char *)NULL);
610 fprintf(stderr, "exec: %s: %s\n", prog, strerror(errno));
611 _exit(1);
612 }
613 close(pair[1]);
614 helper->fd = pair[0];
615 helper->path = xstrdup(path);
616 helper->pid = pid;
617 debug3_f("helper %zu for \"%s\" on fd %d pid %ld", nhelpers,
618 helper->path, helper->fd, (long)helper->pid);
619 helpers = xrecallocarray(helpers, nhelpers,
620 nhelpers + 1, sizeof(*helpers));
621 helpers[nhelpers++] = helper;
622 return helper;
623 }
624
625 int
pkcs11_add_provider(char * name,char * pin,struct sshkey *** keysp,char *** labelsp)626 pkcs11_add_provider(char *name, char *pin, struct sshkey ***keysp,
627 char ***labelsp)
628 {
629 struct sshkey *k;
630 int r, type;
631 u_char *blob;
632 char *label;
633 size_t blen;
634 u_int nkeys, i;
635 struct sshbuf *msg;
636 struct helper *helper;
637
638 if ((helper = helper_by_provider(name)) == NULL &&
639 (helper = pkcs11_start_helper(name)) == NULL)
640 return -1;
641
642 if ((msg = sshbuf_new()) == NULL)
643 fatal_f("sshbuf_new failed");
644 if ((r = sshbuf_put_u8(msg, SSH_AGENTC_ADD_SMARTCARD_KEY)) != 0 ||
645 (r = sshbuf_put_cstring(msg, name)) != 0 ||
646 (r = sshbuf_put_cstring(msg, pin)) != 0)
647 fatal_fr(r, "compose");
648 send_msg(helper->fd, msg);
649 sshbuf_reset(msg);
650
651 type = recv_msg(helper->fd, msg);
652 if (type == SSH2_AGENT_IDENTITIES_ANSWER) {
653 if ((r = sshbuf_get_u32(msg, &nkeys)) != 0)
654 fatal_fr(r, "parse nkeys");
655 *keysp = xcalloc(nkeys, sizeof(struct sshkey *));
656 if (labelsp)
657 *labelsp = xcalloc(nkeys, sizeof(char *));
658 for (i = 0; i < nkeys; i++) {
659 /* XXX clean up properly instead of fatal() */
660 if ((r = sshbuf_get_string(msg, &blob, &blen)) != 0 ||
661 (r = sshbuf_get_cstring(msg, &label, NULL)) != 0)
662 fatal_fr(r, "parse key");
663 if ((r = sshkey_from_blob(blob, blen, &k)) != 0)
664 fatal_fr(r, "decode key");
665 wrap_key(helper, k);
666 (*keysp)[i] = k;
667 if (labelsp)
668 (*labelsp)[i] = label;
669 else
670 free(label);
671 free(blob);
672 }
673 } else if (type == SSH2_AGENT_FAILURE) {
674 if ((r = sshbuf_get_u32(msg, &nkeys)) != 0)
675 nkeys = -1;
676 } else {
677 nkeys = -1;
678 }
679 sshbuf_free(msg);
680 return (nkeys);
681 }
682
683 int
pkcs11_del_provider(char * name)684 pkcs11_del_provider(char *name)
685 {
686 struct helper *helper;
687
688 /*
689 * ssh-agent deletes keys before calling this, so the helper entry
690 * should be gone before we get here.
691 */
692 debug3_f("delete %s", name);
693 if ((helper = helper_by_provider(name)) != NULL)
694 helper_terminate(helper);
695 return 0;
696 }
697 #endif /* ENABLE_PKCS11 */
698