1/* $OpenBSD: ssh-pkcs11-client.c,v 1.19 2023/12/18 14:46:56 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 */
62struct 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};
72static struct helper **helpers;
73static size_t nhelpers;
74
75static struct helper *
76helper_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
90static struct helper *
91helper_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)
107static struct helper *
108helper_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
124static void
125helper_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
158static void
159helper_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
183static void
184send_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
201static int
202recv_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
236int
237pkcs11_init(int interactive)
238{
239	return 0;
240}
241
242void
243pkcs11_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
252static int
253rsa_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	key = sshkey_new(KEY_UNSPEC);
268	if (key == NULL) {
269		error_f("sshkey_new failed");
270		goto fail;
271	}
272	key->type = KEY_RSA;
273	RSA_up_ref(rsa);
274	key->rsa = rsa;
275	if ((r = sshkey_to_blob(key, &blob, &blen)) != 0) {
276		error_fr(r, "encode key");
277		goto fail;
278	}
279	if ((msg = sshbuf_new()) == NULL)
280		fatal_f("sshbuf_new failed");
281	if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 ||
282	    (r = sshbuf_put_string(msg, blob, blen)) != 0 ||
283	    (r = sshbuf_put_string(msg, from, flen)) != 0 ||
284	    (r = sshbuf_put_u32(msg, 0)) != 0)
285		fatal_fr(r, "compose");
286	send_msg(helper->fd, msg);
287	sshbuf_reset(msg);
288
289	if (recv_msg(helper->fd, msg) == SSH2_AGENT_SIGN_RESPONSE) {
290		if ((r = sshbuf_get_string(msg, &signature, &slen)) != 0)
291			fatal_fr(r, "parse");
292		if (slen <= (size_t)RSA_size(rsa)) {
293			memcpy(to, signature, slen);
294			ret = slen;
295		}
296		free(signature);
297	}
298 fail:
299	free(blob);
300	sshkey_free(key);
301	sshbuf_free(msg);
302	return (ret);
303}
304
305static int
306rsa_finish(RSA *rsa)
307{
308	struct helper *helper;
309
310	if ((helper = helper_by_rsa(rsa)) == NULL)
311		fatal_f("no helper for PKCS11 key");
312	debug3_f("free PKCS11 RSA key for provider %s", helper->path);
313	if (helper->rsa_finish != NULL)
314		helper->rsa_finish(rsa);
315	if (helper->nrsa == 0)
316		fatal_f("RSA refcount error");
317	helper->nrsa--;
318	debug3_f("provider %s remaining keys: %zu RSA %zu ECDSA",
319	    helper->path, helper->nrsa, helper->nec);
320	if (helper->nrsa == 0 && helper->nec == 0)
321		helper_terminate(helper);
322	return 1;
323}
324
325#if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
326static ECDSA_SIG *
327ecdsa_do_sign(const unsigned char *dgst, int dgst_len, const BIGNUM *inv,
328    const BIGNUM *rp, EC_KEY *ec)
329{
330	struct sshkey *key = NULL;
331	struct sshbuf *msg = NULL;
332	ECDSA_SIG *ret = NULL;
333	const u_char *cp;
334	u_char *blob = NULL, *signature = NULL;
335	size_t blen, slen = 0;
336	int r, nid;
337	struct helper *helper;
338
339	if ((helper = helper_by_ec(ec)) == NULL || helper->fd == -1)
340		fatal_f("no helper for PKCS11 key");
341	debug3_f("signing with PKCS11 provider %s", helper->path);
342	nid = sshkey_ecdsa_key_to_nid(ec);
343	if (nid < 0) {
344		error_f("couldn't get curve nid");
345		goto fail;
346	}
347
348	key = sshkey_new(KEY_UNSPEC);
349	if (key == NULL) {
350		error_f("sshkey_new failed");
351		goto fail;
352	}
353	key->ecdsa = ec;
354	key->ecdsa_nid = nid;
355	key->type = KEY_ECDSA;
356	EC_KEY_up_ref(ec);
357
358	if ((r = sshkey_to_blob(key, &blob, &blen)) != 0) {
359		error_fr(r, "encode key");
360		goto fail;
361	}
362	if ((msg = sshbuf_new()) == NULL)
363		fatal_f("sshbuf_new failed");
364	if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 ||
365	    (r = sshbuf_put_string(msg, blob, blen)) != 0 ||
366	    (r = sshbuf_put_string(msg, dgst, dgst_len)) != 0 ||
367	    (r = sshbuf_put_u32(msg, 0)) != 0)
368		fatal_fr(r, "compose");
369	send_msg(helper->fd, msg);
370	sshbuf_reset(msg);
371
372	if (recv_msg(helper->fd, msg) == SSH2_AGENT_SIGN_RESPONSE) {
373		if ((r = sshbuf_get_string(msg, &signature, &slen)) != 0)
374			fatal_fr(r, "parse");
375		cp = signature;
376		ret = d2i_ECDSA_SIG(NULL, &cp, slen);
377		free(signature);
378	}
379
380 fail:
381	free(blob);
382	sshkey_free(key);
383	sshbuf_free(msg);
384	return (ret);
385}
386
387static void
388ecdsa_do_finish(EC_KEY *ec)
389{
390	struct helper *helper;
391
392	if ((helper = helper_by_ec(ec)) == NULL)
393		fatal_f("no helper for PKCS11 key");
394	debug3_f("free PKCS11 ECDSA key for provider %s", helper->path);
395	if (helper->ec_finish != NULL)
396		helper->ec_finish(ec);
397	if (helper->nec == 0)
398		fatal_f("ECDSA refcount error");
399	helper->nec--;
400	debug3_f("provider %s remaining keys: %zu RSA %zu ECDSA",
401	    helper->path, helper->nrsa, helper->nec);
402	if (helper->nrsa == 0 && helper->nec == 0)
403		helper_terminate(helper);
404}
405#endif /* defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW) */
406
407/* redirect private key crypto operations to the ssh-pkcs11-helper */
408static void
409wrap_key(struct helper *helper, struct sshkey *k)
410{
411	debug3_f("wrap %s for provider %s", sshkey_type(k), helper->path);
412	if (k->type == KEY_RSA) {
413		RSA_set_method(k->rsa, helper->rsa_meth);
414		if (helper->nrsa++ >= INT_MAX)
415			fatal_f("RSA refcount error");
416#if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
417	} else if (k->type == KEY_ECDSA) {
418		EC_KEY_set_method(k->ecdsa, helper->ec_meth);
419		if (helper->nec++ >= INT_MAX)
420			fatal_f("EC refcount error");
421#endif
422	} else
423		fatal_f("unknown key type");
424	k->flags |= SSHKEY_FLAG_EXT;
425	debug3_f("provider %s remaining keys: %zu RSA %zu ECDSA",
426	    helper->path, helper->nrsa, helper->nec);
427}
428
429/*
430 * Make a private PKCS#11-backed certificate by grafting a previously-loaded
431 * PKCS#11 private key and a public certificate key.
432 */
433int
434pkcs11_make_cert(const struct sshkey *priv,
435    const struct sshkey *certpub, struct sshkey **certprivp)
436{
437	struct helper *helper = NULL;
438	struct sshkey *ret;
439	int r;
440
441	debug3_f("private key type %s cert type %s", sshkey_type(priv),
442	    sshkey_type(certpub));
443	*certprivp = NULL;
444	if (!sshkey_is_cert(certpub) || sshkey_is_cert(priv) ||
445	    !sshkey_equal_public(priv, certpub)) {
446		error_f("private key %s doesn't match cert %s",
447		    sshkey_type(priv), sshkey_type(certpub));
448		return SSH_ERR_INVALID_ARGUMENT;
449	}
450	*certprivp = NULL;
451	if (priv->type == KEY_RSA) {
452		if ((helper = helper_by_rsa(priv->rsa)) == NULL ||
453		    helper->fd == -1)
454			fatal_f("no helper for PKCS11 RSA key");
455		if ((r = sshkey_from_private(priv, &ret)) != 0)
456			fatal_fr(r, "copy key");
457		RSA_set_method(ret->rsa, helper->rsa_meth);
458		if (helper->nrsa++ >= INT_MAX)
459			fatal_f("RSA refcount error");
460#if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
461	} else if (priv->type == KEY_ECDSA) {
462		if ((helper = helper_by_ec(priv->ecdsa)) == NULL ||
463		    helper->fd == -1)
464			fatal_f("no helper for PKCS11 EC key");
465		if ((r = sshkey_from_private(priv, &ret)) != 0)
466			fatal_fr(r, "copy key");
467		EC_KEY_set_method(ret->ecdsa, helper->ec_meth);
468		if (helper->nec++ >= INT_MAX)
469			fatal_f("EC refcount error");
470#endif
471	} else
472		fatal_f("unknown key type %s", sshkey_type(priv));
473
474	ret->flags |= SSHKEY_FLAG_EXT;
475	if ((r = sshkey_to_certified(ret)) != 0 ||
476	    (r = sshkey_cert_copy(certpub, ret)) != 0)
477		fatal_fr(r, "graft certificate");
478	debug3_f("provider %s remaining keys: %zu RSA %zu ECDSA",
479	    helper->path, helper->nrsa, helper->nec);
480	/* success */
481	*certprivp = ret;
482	return 0;
483}
484
485static int
486pkcs11_start_helper_methods(struct helper *helper)
487{
488	RSA_METHOD *rsa_meth;
489	EC_KEY_METHOD *ec_meth = NULL;
490#if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
491	int (*ec_init)(EC_KEY *key);
492	int (*ec_copy)(EC_KEY *dest, const EC_KEY *src);
493	int (*ec_set_group)(EC_KEY *key, const EC_GROUP *grp);
494	int (*ec_set_private)(EC_KEY *key, const BIGNUM *priv_key);
495	int (*ec_set_public)(EC_KEY *key, const EC_POINT *pub_key);
496	int (*ec_sign)(int, const unsigned char *, int, unsigned char *,
497	    unsigned int *, const BIGNUM *, const BIGNUM *, EC_KEY *) = NULL;
498
499	if ((ec_meth = EC_KEY_METHOD_new(EC_KEY_OpenSSL())) == NULL)
500		return -1;
501	EC_KEY_METHOD_get_sign(ec_meth, &ec_sign, NULL, NULL);
502	EC_KEY_METHOD_set_sign(ec_meth, ec_sign, NULL, ecdsa_do_sign);
503	EC_KEY_METHOD_get_init(ec_meth, &ec_init, &helper->ec_finish,
504	    &ec_copy, &ec_set_group, &ec_set_private, &ec_set_public);
505	EC_KEY_METHOD_set_init(ec_meth, ec_init, ecdsa_do_finish,
506	    ec_copy, ec_set_group, ec_set_private, ec_set_public);
507#endif /* defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW) */
508
509	if ((rsa_meth = RSA_meth_dup(RSA_get_default_method())) == NULL)
510		fatal_f("RSA_meth_dup failed");
511	helper->rsa_finish = RSA_meth_get_finish(rsa_meth);
512	if (!RSA_meth_set1_name(rsa_meth, "ssh-pkcs11-helper") ||
513	    !RSA_meth_set_priv_enc(rsa_meth, rsa_encrypt) ||
514	    !RSA_meth_set_finish(rsa_meth, rsa_finish))
515		fatal_f("failed to prepare method");
516
517	helper->ec_meth = ec_meth;
518	helper->rsa_meth = rsa_meth;
519	return 0;
520}
521
522static struct helper *
523pkcs11_start_helper(const char *path)
524{
525	int pair[2];
526	char *prog, *verbosity = NULL;
527	struct helper *helper;
528	pid_t pid;
529
530	if (nhelpers >= INT_MAX)
531		fatal_f("too many helpers");
532	debug3_f("start helper for %s", path);
533	if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) {
534		error_f("socketpair: %s", strerror(errno));
535		return NULL;
536	}
537	helper = xcalloc(1, sizeof(*helper));
538	if (pkcs11_start_helper_methods(helper) == -1) {
539		error_f("pkcs11_start_helper_methods failed");
540		goto fail;
541	}
542	if ((pid = fork()) == -1) {
543		error_f("fork: %s", strerror(errno));
544 fail:
545		close(pair[0]);
546		close(pair[1]);
547		RSA_meth_free(helper->rsa_meth);
548#if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
549		EC_KEY_METHOD_free(helper->ec_meth);
550#endif
551		free(helper);
552		return NULL;
553	} else if (pid == 0) {
554		if ((dup2(pair[1], STDIN_FILENO) == -1) ||
555		    (dup2(pair[1], STDOUT_FILENO) == -1)) {
556			fprintf(stderr, "dup2: %s\n", strerror(errno));
557			_exit(1);
558		}
559		close(pair[0]);
560		close(pair[1]);
561		prog = getenv("SSH_PKCS11_HELPER");
562		if (prog == NULL || strlen(prog) == 0)
563			prog = _PATH_SSH_PKCS11_HELPER;
564		if (log_level_get() >= SYSLOG_LEVEL_DEBUG1)
565			verbosity = "-vvv";
566		debug_f("starting %s %s", prog,
567		    verbosity == NULL ? "" : verbosity);
568		execlp(prog, prog, verbosity, (char *)NULL);
569		fprintf(stderr, "exec: %s: %s\n", prog, strerror(errno));
570		_exit(1);
571	}
572	close(pair[1]);
573	helper->fd = pair[0];
574	helper->path = xstrdup(path);
575	helper->pid = pid;
576	debug3_f("helper %zu for \"%s\" on fd %d pid %ld", nhelpers,
577	    helper->path, helper->fd, (long)helper->pid);
578	helpers = xrecallocarray(helpers, nhelpers,
579	    nhelpers + 1, sizeof(*helpers));
580	helpers[nhelpers++] = helper;
581	return helper;
582}
583
584int
585pkcs11_add_provider(char *name, char *pin, struct sshkey ***keysp,
586    char ***labelsp)
587{
588	struct sshkey *k;
589	int r, type;
590	u_char *blob;
591	char *label;
592	size_t blen;
593	u_int nkeys, i;
594	struct sshbuf *msg;
595	struct helper *helper;
596
597	if ((helper = helper_by_provider(name)) == NULL &&
598	    (helper = pkcs11_start_helper(name)) == NULL)
599		return -1;
600
601	if ((msg = sshbuf_new()) == NULL)
602		fatal_f("sshbuf_new failed");
603	if ((r = sshbuf_put_u8(msg, SSH_AGENTC_ADD_SMARTCARD_KEY)) != 0 ||
604	    (r = sshbuf_put_cstring(msg, name)) != 0 ||
605	    (r = sshbuf_put_cstring(msg, pin)) != 0)
606		fatal_fr(r, "compose");
607	send_msg(helper->fd, msg);
608	sshbuf_reset(msg);
609
610	type = recv_msg(helper->fd, msg);
611	if (type == SSH2_AGENT_IDENTITIES_ANSWER) {
612		if ((r = sshbuf_get_u32(msg, &nkeys)) != 0)
613			fatal_fr(r, "parse nkeys");
614		*keysp = xcalloc(nkeys, sizeof(struct sshkey *));
615		if (labelsp)
616			*labelsp = xcalloc(nkeys, sizeof(char *));
617		for (i = 0; i < nkeys; i++) {
618			/* XXX clean up properly instead of fatal() */
619			if ((r = sshbuf_get_string(msg, &blob, &blen)) != 0 ||
620			    (r = sshbuf_get_cstring(msg, &label, NULL)) != 0)
621				fatal_fr(r, "parse key");
622			if ((r = sshkey_from_blob(blob, blen, &k)) != 0)
623				fatal_fr(r, "decode key");
624			wrap_key(helper, k);
625			(*keysp)[i] = k;
626			if (labelsp)
627				(*labelsp)[i] = label;
628			else
629				free(label);
630			free(blob);
631		}
632	} else if (type == SSH2_AGENT_FAILURE) {
633		if ((r = sshbuf_get_u32(msg, &nkeys)) != 0)
634			nkeys = -1;
635	} else {
636		nkeys = -1;
637	}
638	sshbuf_free(msg);
639	return (nkeys);
640}
641
642int
643pkcs11_del_provider(char *name)
644{
645	struct helper *helper;
646
647	/*
648	 * ssh-agent deletes keys before calling this, so the helper entry
649	 * should be gone before we get here.
650	 */
651	debug3_f("delete %s", name);
652	if ((helper = helper_by_provider(name)) != NULL)
653		helper_terminate(helper);
654	return 0;
655}
656#endif /* ENABLE_PKCS11 */
657