xref: /openssh-portable/sshkey.c (revision 857f49e9)
1 /* $OpenBSD: sshkey.c,v 1.93 2019/11/15 06:00:20 djm Exp $ */
2 /*
3  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
4  * Copyright (c) 2008 Alexander von Gernler.  All rights reserved.
5  * Copyright (c) 2010,2011 Damien Miller.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  */
27 
28 #include "includes.h"
29 
30 #include <sys/types.h>
31 #include <netinet/in.h>
32 
33 #ifdef WITH_OPENSSL
34 #include <openssl/evp.h>
35 #include <openssl/err.h>
36 #include <openssl/pem.h>
37 #endif
38 
39 #include "crypto_api.h"
40 
41 #include <errno.h>
42 #include <limits.h>
43 #include <stdio.h>
44 #include <string.h>
45 #include <resolv.h>
46 #include <time.h>
47 #ifdef HAVE_UTIL_H
48 #include <util.h>
49 #endif /* HAVE_UTIL_H */
50 
51 #include "ssh2.h"
52 #include "ssherr.h"
53 #include "misc.h"
54 #include "sshbuf.h"
55 #include "cipher.h"
56 #include "digest.h"
57 #define SSHKEY_INTERNAL
58 #include "sshkey.h"
59 #include "match.h"
60 #include "ssh-sk.h"
61 
62 #ifdef WITH_XMSS
63 #include "sshkey-xmss.h"
64 #include "xmss_fast.h"
65 #endif
66 
67 #include "openbsd-compat/openssl-compat.h"
68 
69 /* openssh private key file format */
70 #define MARK_BEGIN		"-----BEGIN OPENSSH PRIVATE KEY-----\n"
71 #define MARK_END		"-----END OPENSSH PRIVATE KEY-----\n"
72 #define MARK_BEGIN_LEN		(sizeof(MARK_BEGIN) - 1)
73 #define MARK_END_LEN		(sizeof(MARK_END) - 1)
74 #define KDFNAME			"bcrypt"
75 #define AUTH_MAGIC		"openssh-key-v1"
76 #define SALT_LEN		16
77 #define DEFAULT_CIPHERNAME	"aes256-ctr"
78 #define	DEFAULT_ROUNDS		16
79 
80 /* Version identification string for SSH v1 identity files. */
81 #define LEGACY_BEGIN		"SSH PRIVATE KEY FILE FORMAT 1.1\n"
82 
83 /*
84  * Constants relating to "shielding" support; protection of keys expected
85  * to remain in memory for long durations
86  */
87 #define SSHKEY_SHIELD_PREKEY_LEN	(16 * 1024)
88 #define SSHKEY_SHIELD_CIPHER		"aes256-ctr" /* XXX want AES-EME* */
89 #define SSHKEY_SHIELD_PREKEY_HASH	SSH_DIGEST_SHA512
90 
91 int	sshkey_private_serialize_opt(struct sshkey *key,
92     struct sshbuf *buf, enum sshkey_serialize_rep);
93 static int sshkey_from_blob_internal(struct sshbuf *buf,
94     struct sshkey **keyp, int allow_cert);
95 
96 /* Supported key types */
97 struct keytype {
98 	const char *name;
99 	const char *shortname;
100 	const char *sigalg;
101 	int type;
102 	int nid;
103 	int cert;
104 	int sigonly;
105 };
106 static const struct keytype keytypes[] = {
107 	{ "ssh-ed25519", "ED25519", NULL, KEY_ED25519, 0, 0, 0 },
108 	{ "ssh-ed25519-cert-v01@openssh.com", "ED25519-CERT", NULL,
109 	    KEY_ED25519_CERT, 0, 1, 0 },
110 	{ "sk-ssh-ed25519@openssh.com", "ED25519-SK", NULL,
111 	    KEY_ED25519_SK, 0, 0, 0 },
112 	{ "sk-ssh-ed25519-cert-v01@openssh.com", "ED25519-SK-CERT", NULL,
113 	    KEY_ED25519_SK_CERT, 0, 1, 0 },
114 #ifdef WITH_XMSS
115 	{ "ssh-xmss@openssh.com", "XMSS", NULL, KEY_XMSS, 0, 0, 0 },
116 	{ "ssh-xmss-cert-v01@openssh.com", "XMSS-CERT", NULL,
117 	    KEY_XMSS_CERT, 0, 1, 0 },
118 #endif /* WITH_XMSS */
119 #ifdef WITH_OPENSSL
120 	{ "ssh-rsa", "RSA", NULL, KEY_RSA, 0, 0, 0 },
121 	{ "rsa-sha2-256", "RSA", NULL, KEY_RSA, 0, 0, 1 },
122 	{ "rsa-sha2-512", "RSA", NULL, KEY_RSA, 0, 0, 1 },
123 	{ "ssh-dss", "DSA", NULL, KEY_DSA, 0, 0, 0 },
124 # ifdef OPENSSL_HAS_ECC
125 	{ "ecdsa-sha2-nistp256", "ECDSA", NULL,
126 	    KEY_ECDSA, NID_X9_62_prime256v1, 0, 0 },
127 	{ "ecdsa-sha2-nistp384", "ECDSA", NULL,
128 	    KEY_ECDSA, NID_secp384r1, 0, 0 },
129 #  ifdef OPENSSL_HAS_NISTP521
130 	{ "ecdsa-sha2-nistp521", "ECDSA", NULL,
131 	    KEY_ECDSA, NID_secp521r1, 0, 0 },
132 #  endif /* OPENSSL_HAS_NISTP521 */
133 	{ "sk-ecdsa-sha2-nistp256@openssh.com", "ECDSA-SK", NULL,
134 	    KEY_ECDSA_SK, NID_X9_62_prime256v1, 0, 0 },
135 # endif /* OPENSSL_HAS_ECC */
136 	{ "ssh-rsa-cert-v01@openssh.com", "RSA-CERT", NULL,
137 	    KEY_RSA_CERT, 0, 1, 0 },
138 	{ "rsa-sha2-256-cert-v01@openssh.com", "RSA-CERT",
139 	    "rsa-sha2-256", KEY_RSA_CERT, 0, 1, 1 },
140 	{ "rsa-sha2-512-cert-v01@openssh.com", "RSA-CERT",
141 	    "rsa-sha2-512", KEY_RSA_CERT, 0, 1, 1 },
142 	{ "ssh-dss-cert-v01@openssh.com", "DSA-CERT", NULL,
143 	    KEY_DSA_CERT, 0, 1, 0 },
144 # ifdef OPENSSL_HAS_ECC
145 	{ "ecdsa-sha2-nistp256-cert-v01@openssh.com", "ECDSA-CERT", NULL,
146 	    KEY_ECDSA_CERT, NID_X9_62_prime256v1, 1, 0 },
147 	{ "ecdsa-sha2-nistp384-cert-v01@openssh.com", "ECDSA-CERT", NULL,
148 	    KEY_ECDSA_CERT, NID_secp384r1, 1, 0 },
149 #  ifdef OPENSSL_HAS_NISTP521
150 	{ "ecdsa-sha2-nistp521-cert-v01@openssh.com", "ECDSA-CERT", NULL,
151 	   KEY_ECDSA_CERT, NID_secp521r1, 1, 0 },
152 #  endif /* OPENSSL_HAS_NISTP521 */
153 	{ "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com", "ECDSA-SK-CERT", NULL,
154 	    KEY_ECDSA_SK_CERT, NID_X9_62_prime256v1, 1, 0 },
155 # endif /* OPENSSL_HAS_ECC */
156 #endif /* WITH_OPENSSL */
157 	{ NULL, NULL, NULL, -1, -1, 0, 0 }
158 };
159 
160 const char *
161 sshkey_type(const struct sshkey *k)
162 {
163 	const struct keytype *kt;
164 
165 	for (kt = keytypes; kt->type != -1; kt++) {
166 		if (kt->type == k->type)
167 			return kt->shortname;
168 	}
169 	return "unknown";
170 }
171 
172 static const char *
173 sshkey_ssh_name_from_type_nid(int type, int nid)
174 {
175 	const struct keytype *kt;
176 
177 	for (kt = keytypes; kt->type != -1; kt++) {
178 		if (kt->type == type && (kt->nid == 0 || kt->nid == nid))
179 			return kt->name;
180 	}
181 	return "ssh-unknown";
182 }
183 
184 int
185 sshkey_type_is_cert(int type)
186 {
187 	const struct keytype *kt;
188 
189 	for (kt = keytypes; kt->type != -1; kt++) {
190 		if (kt->type == type)
191 			return kt->cert;
192 	}
193 	return 0;
194 }
195 
196 const char *
197 sshkey_ssh_name(const struct sshkey *k)
198 {
199 	return sshkey_ssh_name_from_type_nid(k->type, k->ecdsa_nid);
200 }
201 
202 const char *
203 sshkey_ssh_name_plain(const struct sshkey *k)
204 {
205 	return sshkey_ssh_name_from_type_nid(sshkey_type_plain(k->type),
206 	    k->ecdsa_nid);
207 }
208 
209 int
210 sshkey_type_from_name(const char *name)
211 {
212 	const struct keytype *kt;
213 
214 	for (kt = keytypes; kt->type != -1; kt++) {
215 		/* Only allow shortname matches for plain key types */
216 		if ((kt->name != NULL && strcmp(name, kt->name) == 0) ||
217 		    (!kt->cert && strcasecmp(kt->shortname, name) == 0))
218 			return kt->type;
219 	}
220 	return KEY_UNSPEC;
221 }
222 
223 static int
224 key_type_is_ecdsa_variant(int type)
225 {
226 	switch (type) {
227 	case KEY_ECDSA:
228 	case KEY_ECDSA_CERT:
229 	case KEY_ECDSA_SK:
230 	case KEY_ECDSA_SK_CERT:
231 		return 1;
232 	}
233 	return 0;
234 }
235 
236 int
237 sshkey_ecdsa_nid_from_name(const char *name)
238 {
239 	const struct keytype *kt;
240 
241 	for (kt = keytypes; kt->type != -1; kt++) {
242 		if (!key_type_is_ecdsa_variant(kt->type))
243 			continue;
244 		if (kt->name != NULL && strcmp(name, kt->name) == 0)
245 			return kt->nid;
246 	}
247 	return -1;
248 }
249 
250 char *
251 sshkey_alg_list(int certs_only, int plain_only, int include_sigonly, char sep)
252 {
253 	char *tmp, *ret = NULL;
254 	size_t nlen, rlen = 0;
255 	const struct keytype *kt;
256 
257 	for (kt = keytypes; kt->type != -1; kt++) {
258 		if (kt->name == NULL)
259 			continue;
260 		if (!include_sigonly && kt->sigonly)
261 			continue;
262 		if ((certs_only && !kt->cert) || (plain_only && kt->cert))
263 			continue;
264 		if (ret != NULL)
265 			ret[rlen++] = sep;
266 		nlen = strlen(kt->name);
267 		if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) {
268 			free(ret);
269 			return NULL;
270 		}
271 		ret = tmp;
272 		memcpy(ret + rlen, kt->name, nlen + 1);
273 		rlen += nlen;
274 	}
275 	return ret;
276 }
277 
278 int
279 sshkey_names_valid2(const char *names, int allow_wildcard)
280 {
281 	char *s, *cp, *p;
282 	const struct keytype *kt;
283 	int type;
284 
285 	if (names == NULL || strcmp(names, "") == 0)
286 		return 0;
287 	if ((s = cp = strdup(names)) == NULL)
288 		return 0;
289 	for ((p = strsep(&cp, ",")); p && *p != '\0';
290 	    (p = strsep(&cp, ","))) {
291 		type = sshkey_type_from_name(p);
292 		if (type == KEY_UNSPEC) {
293 			if (allow_wildcard) {
294 				/*
295 				 * Try matching key types against the string.
296 				 * If any has a positive or negative match then
297 				 * the component is accepted.
298 				 */
299 				for (kt = keytypes; kt->type != -1; kt++) {
300 					if (match_pattern_list(kt->name,
301 					    p, 0) != 0)
302 						break;
303 				}
304 				if (kt->type != -1)
305 					continue;
306 			}
307 			free(s);
308 			return 0;
309 		}
310 	}
311 	free(s);
312 	return 1;
313 }
314 
315 u_int
316 sshkey_size(const struct sshkey *k)
317 {
318 #ifdef WITH_OPENSSL
319 	const BIGNUM *rsa_n, *dsa_p;
320 #endif /* WITH_OPENSSL */
321 
322 	switch (k->type) {
323 #ifdef WITH_OPENSSL
324 	case KEY_RSA:
325 	case KEY_RSA_CERT:
326 		if (k->rsa == NULL)
327 			return 0;
328 		RSA_get0_key(k->rsa, &rsa_n, NULL, NULL);
329 		return BN_num_bits(rsa_n);
330 	case KEY_DSA:
331 	case KEY_DSA_CERT:
332 		if (k->dsa == NULL)
333 			return 0;
334 		DSA_get0_pqg(k->dsa, &dsa_p, NULL, NULL);
335 		return BN_num_bits(dsa_p);
336 	case KEY_ECDSA:
337 	case KEY_ECDSA_CERT:
338 	case KEY_ECDSA_SK:
339 	case KEY_ECDSA_SK_CERT:
340 		return sshkey_curve_nid_to_bits(k->ecdsa_nid);
341 #endif /* WITH_OPENSSL */
342 	case KEY_ED25519:
343 	case KEY_ED25519_CERT:
344 	case KEY_ED25519_SK:
345 	case KEY_ED25519_SK_CERT:
346 	case KEY_XMSS:
347 	case KEY_XMSS_CERT:
348 		return 256;	/* XXX */
349 	}
350 	return 0;
351 }
352 
353 static int
354 sshkey_type_is_valid_ca(int type)
355 {
356 	switch (type) {
357 	case KEY_RSA:
358 	case KEY_DSA:
359 	case KEY_ECDSA:
360 	case KEY_ECDSA_SK:
361 	case KEY_ED25519:
362 	case KEY_ED25519_SK:
363 	case KEY_XMSS:
364 		return 1;
365 	default:
366 		return 0;
367 	}
368 }
369 
370 int
371 sshkey_is_cert(const struct sshkey *k)
372 {
373 	if (k == NULL)
374 		return 0;
375 	return sshkey_type_is_cert(k->type);
376 }
377 
378 int
379 sshkey_is_sk(const struct sshkey *k)
380 {
381 	if (k == NULL)
382 		return 0;
383 	switch (sshkey_type_plain(k->type)) {
384 	case KEY_ECDSA_SK:
385 	case KEY_ED25519_SK:
386 		return 1;
387 	default:
388 		return 0;
389 	}
390 }
391 
392 /* Return the cert-less equivalent to a certified key type */
393 int
394 sshkey_type_plain(int type)
395 {
396 	switch (type) {
397 	case KEY_RSA_CERT:
398 		return KEY_RSA;
399 	case KEY_DSA_CERT:
400 		return KEY_DSA;
401 	case KEY_ECDSA_CERT:
402 		return KEY_ECDSA;
403 	case KEY_ECDSA_SK_CERT:
404 		return KEY_ECDSA_SK;
405 	case KEY_ED25519_CERT:
406 		return KEY_ED25519;
407 	case KEY_ED25519_SK_CERT:
408 		return KEY_ED25519_SK;
409 	case KEY_XMSS_CERT:
410 		return KEY_XMSS;
411 	default:
412 		return type;
413 	}
414 }
415 
416 #ifdef WITH_OPENSSL
417 /* XXX: these are really begging for a table-driven approach */
418 int
419 sshkey_curve_name_to_nid(const char *name)
420 {
421 	if (strcmp(name, "nistp256") == 0)
422 		return NID_X9_62_prime256v1;
423 	else if (strcmp(name, "nistp384") == 0)
424 		return NID_secp384r1;
425 # ifdef OPENSSL_HAS_NISTP521
426 	else if (strcmp(name, "nistp521") == 0)
427 		return NID_secp521r1;
428 # endif /* OPENSSL_HAS_NISTP521 */
429 	else
430 		return -1;
431 }
432 
433 u_int
434 sshkey_curve_nid_to_bits(int nid)
435 {
436 	switch (nid) {
437 	case NID_X9_62_prime256v1:
438 		return 256;
439 	case NID_secp384r1:
440 		return 384;
441 # ifdef OPENSSL_HAS_NISTP521
442 	case NID_secp521r1:
443 		return 521;
444 # endif /* OPENSSL_HAS_NISTP521 */
445 	default:
446 		return 0;
447 	}
448 }
449 
450 int
451 sshkey_ecdsa_bits_to_nid(int bits)
452 {
453 	switch (bits) {
454 	case 256:
455 		return NID_X9_62_prime256v1;
456 	case 384:
457 		return NID_secp384r1;
458 # ifdef OPENSSL_HAS_NISTP521
459 	case 521:
460 		return NID_secp521r1;
461 # endif /* OPENSSL_HAS_NISTP521 */
462 	default:
463 		return -1;
464 	}
465 }
466 
467 const char *
468 sshkey_curve_nid_to_name(int nid)
469 {
470 	switch (nid) {
471 	case NID_X9_62_prime256v1:
472 		return "nistp256";
473 	case NID_secp384r1:
474 		return "nistp384";
475 # ifdef OPENSSL_HAS_NISTP521
476 	case NID_secp521r1:
477 		return "nistp521";
478 # endif /* OPENSSL_HAS_NISTP521 */
479 	default:
480 		return NULL;
481 	}
482 }
483 
484 int
485 sshkey_ec_nid_to_hash_alg(int nid)
486 {
487 	int kbits = sshkey_curve_nid_to_bits(nid);
488 
489 	if (kbits <= 0)
490 		return -1;
491 
492 	/* RFC5656 section 6.2.1 */
493 	if (kbits <= 256)
494 		return SSH_DIGEST_SHA256;
495 	else if (kbits <= 384)
496 		return SSH_DIGEST_SHA384;
497 	else
498 		return SSH_DIGEST_SHA512;
499 }
500 #endif /* WITH_OPENSSL */
501 
502 static void
503 cert_free(struct sshkey_cert *cert)
504 {
505 	u_int i;
506 
507 	if (cert == NULL)
508 		return;
509 	sshbuf_free(cert->certblob);
510 	sshbuf_free(cert->critical);
511 	sshbuf_free(cert->extensions);
512 	free(cert->key_id);
513 	for (i = 0; i < cert->nprincipals; i++)
514 		free(cert->principals[i]);
515 	free(cert->principals);
516 	sshkey_free(cert->signature_key);
517 	free(cert->signature_type);
518 	freezero(cert, sizeof(*cert));
519 }
520 
521 static struct sshkey_cert *
522 cert_new(void)
523 {
524 	struct sshkey_cert *cert;
525 
526 	if ((cert = calloc(1, sizeof(*cert))) == NULL)
527 		return NULL;
528 	if ((cert->certblob = sshbuf_new()) == NULL ||
529 	    (cert->critical = sshbuf_new()) == NULL ||
530 	    (cert->extensions = sshbuf_new()) == NULL) {
531 		cert_free(cert);
532 		return NULL;
533 	}
534 	cert->key_id = NULL;
535 	cert->principals = NULL;
536 	cert->signature_key = NULL;
537 	cert->signature_type = NULL;
538 	return cert;
539 }
540 
541 struct sshkey *
542 sshkey_new(int type)
543 {
544 	struct sshkey *k;
545 #ifdef WITH_OPENSSL
546 	RSA *rsa;
547 	DSA *dsa;
548 #endif /* WITH_OPENSSL */
549 
550 	if ((k = calloc(1, sizeof(*k))) == NULL)
551 		return NULL;
552 	k->type = type;
553 	k->ecdsa = NULL;
554 	k->ecdsa_nid = -1;
555 	k->dsa = NULL;
556 	k->rsa = NULL;
557 	k->cert = NULL;
558 	k->ed25519_sk = NULL;
559 	k->ed25519_pk = NULL;
560 	k->xmss_sk = NULL;
561 	k->xmss_pk = NULL;
562 	switch (k->type) {
563 #ifdef WITH_OPENSSL
564 	case KEY_RSA:
565 	case KEY_RSA_CERT:
566 		if ((rsa = RSA_new()) == NULL) {
567 			free(k);
568 			return NULL;
569 		}
570 		k->rsa = rsa;
571 		break;
572 	case KEY_DSA:
573 	case KEY_DSA_CERT:
574 		if ((dsa = DSA_new()) == NULL) {
575 			free(k);
576 			return NULL;
577 		}
578 		k->dsa = dsa;
579 		break;
580 	case KEY_ECDSA:
581 	case KEY_ECDSA_CERT:
582 	case KEY_ECDSA_SK:
583 	case KEY_ECDSA_SK_CERT:
584 		/* Cannot do anything until we know the group */
585 		break;
586 #endif /* WITH_OPENSSL */
587 	case KEY_ED25519:
588 	case KEY_ED25519_CERT:
589 	case KEY_ED25519_SK:
590 	case KEY_ED25519_SK_CERT:
591 	case KEY_XMSS:
592 	case KEY_XMSS_CERT:
593 		/* no need to prealloc */
594 		break;
595 	case KEY_UNSPEC:
596 		break;
597 	default:
598 		free(k);
599 		return NULL;
600 	}
601 
602 	if (sshkey_is_cert(k)) {
603 		if ((k->cert = cert_new()) == NULL) {
604 			sshkey_free(k);
605 			return NULL;
606 		}
607 	}
608 
609 	return k;
610 }
611 
612 void
613 sshkey_free(struct sshkey *k)
614 {
615 	if (k == NULL)
616 		return;
617 	switch (k->type) {
618 #ifdef WITH_OPENSSL
619 	case KEY_RSA:
620 	case KEY_RSA_CERT:
621 		RSA_free(k->rsa);
622 		k->rsa = NULL;
623 		break;
624 	case KEY_DSA:
625 	case KEY_DSA_CERT:
626 		DSA_free(k->dsa);
627 		k->dsa = NULL;
628 		break;
629 # ifdef OPENSSL_HAS_ECC
630 	case KEY_ECDSA_SK:
631 	case KEY_ECDSA_SK_CERT:
632 		free(k->sk_application);
633 		sshbuf_free(k->sk_key_handle);
634 		sshbuf_free(k->sk_reserved);
635 		/* FALLTHROUGH */
636 	case KEY_ECDSA:
637 	case KEY_ECDSA_CERT:
638 		EC_KEY_free(k->ecdsa);
639 		k->ecdsa = NULL;
640 		break;
641 # endif /* OPENSSL_HAS_ECC */
642 #endif /* WITH_OPENSSL */
643 	case KEY_ED25519_SK:
644 	case KEY_ED25519_SK_CERT:
645 		free(k->sk_application);
646 		sshbuf_free(k->sk_key_handle);
647 		sshbuf_free(k->sk_reserved);
648 		/* FALLTHROUGH */
649 	case KEY_ED25519:
650 	case KEY_ED25519_CERT:
651 		freezero(k->ed25519_pk, ED25519_PK_SZ);
652 		k->ed25519_pk = NULL;
653 		freezero(k->ed25519_sk, ED25519_SK_SZ);
654 		k->ed25519_sk = NULL;
655 		break;
656 #ifdef WITH_XMSS
657 	case KEY_XMSS:
658 	case KEY_XMSS_CERT:
659 		freezero(k->xmss_pk, sshkey_xmss_pklen(k));
660 		k->xmss_pk = NULL;
661 		freezero(k->xmss_sk, sshkey_xmss_sklen(k));
662 		k->xmss_sk = NULL;
663 		sshkey_xmss_free_state(k);
664 		free(k->xmss_name);
665 		k->xmss_name = NULL;
666 		free(k->xmss_filename);
667 		k->xmss_filename = NULL;
668 		break;
669 #endif /* WITH_XMSS */
670 	case KEY_UNSPEC:
671 		break;
672 	default:
673 		break;
674 	}
675 	if (sshkey_is_cert(k))
676 		cert_free(k->cert);
677 	freezero(k->shielded_private, k->shielded_len);
678 	freezero(k->shield_prekey, k->shield_prekey_len);
679 	freezero(k, sizeof(*k));
680 }
681 
682 static int
683 cert_compare(struct sshkey_cert *a, struct sshkey_cert *b)
684 {
685 	if (a == NULL && b == NULL)
686 		return 1;
687 	if (a == NULL || b == NULL)
688 		return 0;
689 	if (sshbuf_len(a->certblob) != sshbuf_len(b->certblob))
690 		return 0;
691 	if (timingsafe_bcmp(sshbuf_ptr(a->certblob), sshbuf_ptr(b->certblob),
692 	    sshbuf_len(a->certblob)) != 0)
693 		return 0;
694 	return 1;
695 }
696 
697 /*
698  * Compare public portions of key only, allowing comparisons between
699  * certificates and plain keys too.
700  */
701 int
702 sshkey_equal_public(const struct sshkey *a, const struct sshkey *b)
703 {
704 #if defined(WITH_OPENSSL)
705 	const BIGNUM *rsa_e_a, *rsa_n_a;
706 	const BIGNUM *rsa_e_b, *rsa_n_b;
707 	const BIGNUM *dsa_p_a, *dsa_q_a, *dsa_g_a, *dsa_pub_key_a;
708 	const BIGNUM *dsa_p_b, *dsa_q_b, *dsa_g_b, *dsa_pub_key_b;
709 #endif /* WITH_OPENSSL */
710 
711 	if (a == NULL || b == NULL ||
712 	    sshkey_type_plain(a->type) != sshkey_type_plain(b->type))
713 		return 0;
714 
715 	switch (a->type) {
716 #ifdef WITH_OPENSSL
717 	case KEY_RSA_CERT:
718 	case KEY_RSA:
719 		if (a->rsa == NULL || b->rsa == NULL)
720 			return 0;
721 		RSA_get0_key(a->rsa, &rsa_n_a, &rsa_e_a, NULL);
722 		RSA_get0_key(b->rsa, &rsa_n_b, &rsa_e_b, NULL);
723 		return BN_cmp(rsa_e_a, rsa_e_b) == 0 &&
724 		    BN_cmp(rsa_n_a, rsa_n_b) == 0;
725 	case KEY_DSA_CERT:
726 	case KEY_DSA:
727 		if (a->dsa == NULL || b->dsa == NULL)
728 			return 0;
729 		DSA_get0_pqg(a->dsa, &dsa_p_a, &dsa_q_a, &dsa_g_a);
730 		DSA_get0_pqg(b->dsa, &dsa_p_b, &dsa_q_b, &dsa_g_b);
731 		DSA_get0_key(a->dsa, &dsa_pub_key_a, NULL);
732 		DSA_get0_key(b->dsa, &dsa_pub_key_b, NULL);
733 		return BN_cmp(dsa_p_a, dsa_p_b) == 0 &&
734 		    BN_cmp(dsa_q_a, dsa_q_b) == 0 &&
735 		    BN_cmp(dsa_g_a, dsa_g_b) == 0 &&
736 		    BN_cmp(dsa_pub_key_a, dsa_pub_key_b) == 0;
737 # ifdef OPENSSL_HAS_ECC
738 	case KEY_ECDSA_SK:
739 	case KEY_ECDSA_SK_CERT:
740 		if (a->sk_application == NULL || b->sk_application == NULL)
741 			return 0;
742 		if (strcmp(a->sk_application, b->sk_application) != 0)
743 			return 0;
744 		/* FALLTHROUGH */
745 	case KEY_ECDSA_CERT:
746 	case KEY_ECDSA:
747 		if (a->ecdsa == NULL || b->ecdsa == NULL ||
748 		    EC_KEY_get0_public_key(a->ecdsa) == NULL ||
749 		    EC_KEY_get0_public_key(b->ecdsa) == NULL)
750 			return 0;
751 		if (EC_GROUP_cmp(EC_KEY_get0_group(a->ecdsa),
752 		    EC_KEY_get0_group(b->ecdsa), NULL) != 0 ||
753 		    EC_POINT_cmp(EC_KEY_get0_group(a->ecdsa),
754 		    EC_KEY_get0_public_key(a->ecdsa),
755 		    EC_KEY_get0_public_key(b->ecdsa), NULL) != 0)
756 			return 0;
757 		return 1;
758 # endif /* OPENSSL_HAS_ECC */
759 #endif /* WITH_OPENSSL */
760 	case KEY_ED25519_SK:
761 	case KEY_ED25519_SK_CERT:
762 		if (a->sk_application == NULL || b->sk_application == NULL)
763 			return 0;
764 		if (strcmp(a->sk_application, b->sk_application) != 0)
765 			return 0;
766 		/* FALLTHROUGH */
767 	case KEY_ED25519:
768 	case KEY_ED25519_CERT:
769 		return a->ed25519_pk != NULL && b->ed25519_pk != NULL &&
770 		    memcmp(a->ed25519_pk, b->ed25519_pk, ED25519_PK_SZ) == 0;
771 #ifdef WITH_XMSS
772 	case KEY_XMSS:
773 	case KEY_XMSS_CERT:
774 		return a->xmss_pk != NULL && b->xmss_pk != NULL &&
775 		    sshkey_xmss_pklen(a) == sshkey_xmss_pklen(b) &&
776 		    memcmp(a->xmss_pk, b->xmss_pk, sshkey_xmss_pklen(a)) == 0;
777 #endif /* WITH_XMSS */
778 	default:
779 		return 0;
780 	}
781 	/* NOTREACHED */
782 }
783 
784 int
785 sshkey_equal(const struct sshkey *a, const struct sshkey *b)
786 {
787 	if (a == NULL || b == NULL || a->type != b->type)
788 		return 0;
789 	if (sshkey_is_cert(a)) {
790 		if (!cert_compare(a->cert, b->cert))
791 			return 0;
792 	}
793 	return sshkey_equal_public(a, b);
794 }
795 
796 static int
797 to_blob_buf(const struct sshkey *key, struct sshbuf *b, int force_plain,
798   enum sshkey_serialize_rep opts)
799 {
800 	int type, ret = SSH_ERR_INTERNAL_ERROR;
801 	const char *typename;
802 #ifdef WITH_OPENSSL
803 	const BIGNUM *rsa_n, *rsa_e, *dsa_p, *dsa_q, *dsa_g, *dsa_pub_key;
804 #endif /* WITH_OPENSSL */
805 
806 	if (key == NULL)
807 		return SSH_ERR_INVALID_ARGUMENT;
808 
809 	if (sshkey_is_cert(key)) {
810 		if (key->cert == NULL)
811 			return SSH_ERR_EXPECTED_CERT;
812 		if (sshbuf_len(key->cert->certblob) == 0)
813 			return SSH_ERR_KEY_LACKS_CERTBLOB;
814 	}
815 	type = force_plain ? sshkey_type_plain(key->type) : key->type;
816 	typename = sshkey_ssh_name_from_type_nid(type, key->ecdsa_nid);
817 
818 	switch (type) {
819 #ifdef WITH_OPENSSL
820 	case KEY_DSA_CERT:
821 	case KEY_ECDSA_CERT:
822 	case KEY_ECDSA_SK_CERT:
823 	case KEY_RSA_CERT:
824 #endif /* WITH_OPENSSL */
825 	case KEY_ED25519_CERT:
826 #ifdef WITH_XMSS
827 	case KEY_XMSS_CERT:
828 #endif /* WITH_XMSS */
829 		/* Use the existing blob */
830 		/* XXX modified flag? */
831 		if ((ret = sshbuf_putb(b, key->cert->certblob)) != 0)
832 			return ret;
833 		break;
834 #ifdef WITH_OPENSSL
835 	case KEY_DSA:
836 		if (key->dsa == NULL)
837 			return SSH_ERR_INVALID_ARGUMENT;
838 		DSA_get0_pqg(key->dsa, &dsa_p, &dsa_q, &dsa_g);
839 		DSA_get0_key(key->dsa, &dsa_pub_key, NULL);
840 		if ((ret = sshbuf_put_cstring(b, typename)) != 0 ||
841 		    (ret = sshbuf_put_bignum2(b, dsa_p)) != 0 ||
842 		    (ret = sshbuf_put_bignum2(b, dsa_q)) != 0 ||
843 		    (ret = sshbuf_put_bignum2(b, dsa_g)) != 0 ||
844 		    (ret = sshbuf_put_bignum2(b, dsa_pub_key)) != 0)
845 			return ret;
846 		break;
847 # ifdef OPENSSL_HAS_ECC
848 	case KEY_ECDSA:
849 	case KEY_ECDSA_SK:
850 		if (key->ecdsa == NULL)
851 			return SSH_ERR_INVALID_ARGUMENT;
852 		if ((ret = sshbuf_put_cstring(b, typename)) != 0 ||
853 		    (ret = sshbuf_put_cstring(b,
854 		    sshkey_curve_nid_to_name(key->ecdsa_nid))) != 0 ||
855 		    (ret = sshbuf_put_eckey(b, key->ecdsa)) != 0)
856 			return ret;
857 		if (type == KEY_ECDSA_SK) {
858 			if ((ret = sshbuf_put_cstring(b,
859 			    key->sk_application)) != 0)
860 				return ret;
861 		}
862 		break;
863 # endif
864 	case KEY_RSA:
865 		if (key->rsa == NULL)
866 			return SSH_ERR_INVALID_ARGUMENT;
867 		RSA_get0_key(key->rsa, &rsa_n, &rsa_e, NULL);
868 		if ((ret = sshbuf_put_cstring(b, typename)) != 0 ||
869 		    (ret = sshbuf_put_bignum2(b, rsa_e)) != 0 ||
870 		    (ret = sshbuf_put_bignum2(b, rsa_n)) != 0)
871 			return ret;
872 		break;
873 #endif /* WITH_OPENSSL */
874 	case KEY_ED25519:
875 	case KEY_ED25519_SK:
876 		if (key->ed25519_pk == NULL)
877 			return SSH_ERR_INVALID_ARGUMENT;
878 		if ((ret = sshbuf_put_cstring(b, typename)) != 0 ||
879 		    (ret = sshbuf_put_string(b,
880 		    key->ed25519_pk, ED25519_PK_SZ)) != 0)
881 			return ret;
882 		if (type == KEY_ED25519_SK) {
883 			if ((ret = sshbuf_put_cstring(b,
884 			    key->sk_application)) != 0)
885 				return ret;
886 		}
887 		break;
888 #ifdef WITH_XMSS
889 	case KEY_XMSS:
890 		if (key->xmss_name == NULL || key->xmss_pk == NULL ||
891 		    sshkey_xmss_pklen(key) == 0)
892 			return SSH_ERR_INVALID_ARGUMENT;
893 		if ((ret = sshbuf_put_cstring(b, typename)) != 0 ||
894 		    (ret = sshbuf_put_cstring(b, key->xmss_name)) != 0 ||
895 		    (ret = sshbuf_put_string(b,
896 		    key->xmss_pk, sshkey_xmss_pklen(key))) != 0 ||
897 		    (ret = sshkey_xmss_serialize_pk_info(key, b, opts)) != 0)
898 			return ret;
899 		break;
900 #endif /* WITH_XMSS */
901 	default:
902 		return SSH_ERR_KEY_TYPE_UNKNOWN;
903 	}
904 	return 0;
905 }
906 
907 int
908 sshkey_putb(const struct sshkey *key, struct sshbuf *b)
909 {
910 	return to_blob_buf(key, b, 0, SSHKEY_SERIALIZE_DEFAULT);
911 }
912 
913 int
914 sshkey_puts_opts(const struct sshkey *key, struct sshbuf *b,
915     enum sshkey_serialize_rep opts)
916 {
917 	struct sshbuf *tmp;
918 	int r;
919 
920 	if ((tmp = sshbuf_new()) == NULL)
921 		return SSH_ERR_ALLOC_FAIL;
922 	r = to_blob_buf(key, tmp, 0, opts);
923 	if (r == 0)
924 		r = sshbuf_put_stringb(b, tmp);
925 	sshbuf_free(tmp);
926 	return r;
927 }
928 
929 int
930 sshkey_puts(const struct sshkey *key, struct sshbuf *b)
931 {
932 	return sshkey_puts_opts(key, b, SSHKEY_SERIALIZE_DEFAULT);
933 }
934 
935 int
936 sshkey_putb_plain(const struct sshkey *key, struct sshbuf *b)
937 {
938 	return to_blob_buf(key, b, 1, SSHKEY_SERIALIZE_DEFAULT);
939 }
940 
941 static int
942 to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp, int force_plain,
943     enum sshkey_serialize_rep opts)
944 {
945 	int ret = SSH_ERR_INTERNAL_ERROR;
946 	size_t len;
947 	struct sshbuf *b = NULL;
948 
949 	if (lenp != NULL)
950 		*lenp = 0;
951 	if (blobp != NULL)
952 		*blobp = NULL;
953 	if ((b = sshbuf_new()) == NULL)
954 		return SSH_ERR_ALLOC_FAIL;
955 	if ((ret = to_blob_buf(key, b, force_plain, opts)) != 0)
956 		goto out;
957 	len = sshbuf_len(b);
958 	if (lenp != NULL)
959 		*lenp = len;
960 	if (blobp != NULL) {
961 		if ((*blobp = malloc(len)) == NULL) {
962 			ret = SSH_ERR_ALLOC_FAIL;
963 			goto out;
964 		}
965 		memcpy(*blobp, sshbuf_ptr(b), len);
966 	}
967 	ret = 0;
968  out:
969 	sshbuf_free(b);
970 	return ret;
971 }
972 
973 int
974 sshkey_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp)
975 {
976 	return to_blob(key, blobp, lenp, 0, SSHKEY_SERIALIZE_DEFAULT);
977 }
978 
979 int
980 sshkey_plain_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp)
981 {
982 	return to_blob(key, blobp, lenp, 1, SSHKEY_SERIALIZE_DEFAULT);
983 }
984 
985 int
986 sshkey_fingerprint_raw(const struct sshkey *k, int dgst_alg,
987     u_char **retp, size_t *lenp)
988 {
989 	u_char *blob = NULL, *ret = NULL;
990 	size_t blob_len = 0;
991 	int r = SSH_ERR_INTERNAL_ERROR;
992 
993 	if (retp != NULL)
994 		*retp = NULL;
995 	if (lenp != NULL)
996 		*lenp = 0;
997 	if (ssh_digest_bytes(dgst_alg) == 0) {
998 		r = SSH_ERR_INVALID_ARGUMENT;
999 		goto out;
1000 	}
1001 	if ((r = to_blob(k, &blob, &blob_len, 1, SSHKEY_SERIALIZE_DEFAULT))
1002 	    != 0)
1003 		goto out;
1004 	if ((ret = calloc(1, SSH_DIGEST_MAX_LENGTH)) == NULL) {
1005 		r = SSH_ERR_ALLOC_FAIL;
1006 		goto out;
1007 	}
1008 	if ((r = ssh_digest_memory(dgst_alg, blob, blob_len,
1009 	    ret, SSH_DIGEST_MAX_LENGTH)) != 0)
1010 		goto out;
1011 	/* success */
1012 	if (retp != NULL) {
1013 		*retp = ret;
1014 		ret = NULL;
1015 	}
1016 	if (lenp != NULL)
1017 		*lenp = ssh_digest_bytes(dgst_alg);
1018 	r = 0;
1019  out:
1020 	free(ret);
1021 	if (blob != NULL) {
1022 		explicit_bzero(blob, blob_len);
1023 		free(blob);
1024 	}
1025 	return r;
1026 }
1027 
1028 static char *
1029 fingerprint_b64(const char *alg, u_char *dgst_raw, size_t dgst_raw_len)
1030 {
1031 	char *ret;
1032 	size_t plen = strlen(alg) + 1;
1033 	size_t rlen = ((dgst_raw_len + 2) / 3) * 4 + plen + 1;
1034 
1035 	if (dgst_raw_len > 65536 || (ret = calloc(1, rlen)) == NULL)
1036 		return NULL;
1037 	strlcpy(ret, alg, rlen);
1038 	strlcat(ret, ":", rlen);
1039 	if (dgst_raw_len == 0)
1040 		return ret;
1041 	if (b64_ntop(dgst_raw, dgst_raw_len, ret + plen, rlen - plen) == -1) {
1042 		freezero(ret, rlen);
1043 		return NULL;
1044 	}
1045 	/* Trim padding characters from end */
1046 	ret[strcspn(ret, "=")] = '\0';
1047 	return ret;
1048 }
1049 
1050 static char *
1051 fingerprint_hex(const char *alg, u_char *dgst_raw, size_t dgst_raw_len)
1052 {
1053 	char *retval, hex[5];
1054 	size_t i, rlen = dgst_raw_len * 3 + strlen(alg) + 2;
1055 
1056 	if (dgst_raw_len > 65536 || (retval = calloc(1, rlen)) == NULL)
1057 		return NULL;
1058 	strlcpy(retval, alg, rlen);
1059 	strlcat(retval, ":", rlen);
1060 	for (i = 0; i < dgst_raw_len; i++) {
1061 		snprintf(hex, sizeof(hex), "%s%02x",
1062 		    i > 0 ? ":" : "", dgst_raw[i]);
1063 		strlcat(retval, hex, rlen);
1064 	}
1065 	return retval;
1066 }
1067 
1068 static char *
1069 fingerprint_bubblebabble(u_char *dgst_raw, size_t dgst_raw_len)
1070 {
1071 	char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' };
1072 	char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm',
1073 	    'n', 'p', 'r', 's', 't', 'v', 'z', 'x' };
1074 	u_int i, j = 0, rounds, seed = 1;
1075 	char *retval;
1076 
1077 	rounds = (dgst_raw_len / 2) + 1;
1078 	if ((retval = calloc(rounds, 6)) == NULL)
1079 		return NULL;
1080 	retval[j++] = 'x';
1081 	for (i = 0; i < rounds; i++) {
1082 		u_int idx0, idx1, idx2, idx3, idx4;
1083 		if ((i + 1 < rounds) || (dgst_raw_len % 2 != 0)) {
1084 			idx0 = (((((u_int)(dgst_raw[2 * i])) >> 6) & 3) +
1085 			    seed) % 6;
1086 			idx1 = (((u_int)(dgst_raw[2 * i])) >> 2) & 15;
1087 			idx2 = ((((u_int)(dgst_raw[2 * i])) & 3) +
1088 			    (seed / 6)) % 6;
1089 			retval[j++] = vowels[idx0];
1090 			retval[j++] = consonants[idx1];
1091 			retval[j++] = vowels[idx2];
1092 			if ((i + 1) < rounds) {
1093 				idx3 = (((u_int)(dgst_raw[(2 * i) + 1])) >> 4) & 15;
1094 				idx4 = (((u_int)(dgst_raw[(2 * i) + 1]))) & 15;
1095 				retval[j++] = consonants[idx3];
1096 				retval[j++] = '-';
1097 				retval[j++] = consonants[idx4];
1098 				seed = ((seed * 5) +
1099 				    ((((u_int)(dgst_raw[2 * i])) * 7) +
1100 				    ((u_int)(dgst_raw[(2 * i) + 1])))) % 36;
1101 			}
1102 		} else {
1103 			idx0 = seed % 6;
1104 			idx1 = 16;
1105 			idx2 = seed / 6;
1106 			retval[j++] = vowels[idx0];
1107 			retval[j++] = consonants[idx1];
1108 			retval[j++] = vowels[idx2];
1109 		}
1110 	}
1111 	retval[j++] = 'x';
1112 	retval[j++] = '\0';
1113 	return retval;
1114 }
1115 
1116 /*
1117  * Draw an ASCII-Art representing the fingerprint so human brain can
1118  * profit from its built-in pattern recognition ability.
1119  * This technique is called "random art" and can be found in some
1120  * scientific publications like this original paper:
1121  *
1122  * "Hash Visualization: a New Technique to improve Real-World Security",
1123  * Perrig A. and Song D., 1999, International Workshop on Cryptographic
1124  * Techniques and E-Commerce (CrypTEC '99)
1125  * sparrow.ece.cmu.edu/~adrian/projects/validation/validation.pdf
1126  *
1127  * The subject came up in a talk by Dan Kaminsky, too.
1128  *
1129  * If you see the picture is different, the key is different.
1130  * If the picture looks the same, you still know nothing.
1131  *
1132  * The algorithm used here is a worm crawling over a discrete plane,
1133  * leaving a trace (augmenting the field) everywhere it goes.
1134  * Movement is taken from dgst_raw 2bit-wise.  Bumping into walls
1135  * makes the respective movement vector be ignored for this turn.
1136  * Graphs are not unambiguous, because circles in graphs can be
1137  * walked in either direction.
1138  */
1139 
1140 /*
1141  * Field sizes for the random art.  Have to be odd, so the starting point
1142  * can be in the exact middle of the picture, and FLDBASE should be >=8 .
1143  * Else pictures would be too dense, and drawing the frame would
1144  * fail, too, because the key type would not fit in anymore.
1145  */
1146 #define	FLDBASE		8
1147 #define	FLDSIZE_Y	(FLDBASE + 1)
1148 #define	FLDSIZE_X	(FLDBASE * 2 + 1)
1149 static char *
1150 fingerprint_randomart(const char *alg, u_char *dgst_raw, size_t dgst_raw_len,
1151     const struct sshkey *k)
1152 {
1153 	/*
1154 	 * Chars to be used after each other every time the worm
1155 	 * intersects with itself.  Matter of taste.
1156 	 */
1157 	char	*augmentation_string = " .o+=*BOX@%&#/^SE";
1158 	char	*retval, *p, title[FLDSIZE_X], hash[FLDSIZE_X];
1159 	u_char	 field[FLDSIZE_X][FLDSIZE_Y];
1160 	size_t	 i, tlen, hlen;
1161 	u_int	 b;
1162 	int	 x, y, r;
1163 	size_t	 len = strlen(augmentation_string) - 1;
1164 
1165 	if ((retval = calloc((FLDSIZE_X + 3), (FLDSIZE_Y + 2))) == NULL)
1166 		return NULL;
1167 
1168 	/* initialize field */
1169 	memset(field, 0, FLDSIZE_X * FLDSIZE_Y * sizeof(char));
1170 	x = FLDSIZE_X / 2;
1171 	y = FLDSIZE_Y / 2;
1172 
1173 	/* process raw key */
1174 	for (i = 0; i < dgst_raw_len; i++) {
1175 		int input;
1176 		/* each byte conveys four 2-bit move commands */
1177 		input = dgst_raw[i];
1178 		for (b = 0; b < 4; b++) {
1179 			/* evaluate 2 bit, rest is shifted later */
1180 			x += (input & 0x1) ? 1 : -1;
1181 			y += (input & 0x2) ? 1 : -1;
1182 
1183 			/* assure we are still in bounds */
1184 			x = MAXIMUM(x, 0);
1185 			y = MAXIMUM(y, 0);
1186 			x = MINIMUM(x, FLDSIZE_X - 1);
1187 			y = MINIMUM(y, FLDSIZE_Y - 1);
1188 
1189 			/* augment the field */
1190 			if (field[x][y] < len - 2)
1191 				field[x][y]++;
1192 			input = input >> 2;
1193 		}
1194 	}
1195 
1196 	/* mark starting point and end point*/
1197 	field[FLDSIZE_X / 2][FLDSIZE_Y / 2] = len - 1;
1198 	field[x][y] = len;
1199 
1200 	/* assemble title */
1201 	r = snprintf(title, sizeof(title), "[%s %u]",
1202 		sshkey_type(k), sshkey_size(k));
1203 	/* If [type size] won't fit, then try [type]; fits "[ED25519-CERT]" */
1204 	if (r < 0 || r > (int)sizeof(title))
1205 		r = snprintf(title, sizeof(title), "[%s]", sshkey_type(k));
1206 	tlen = (r <= 0) ? 0 : strlen(title);
1207 
1208 	/* assemble hash ID. */
1209 	r = snprintf(hash, sizeof(hash), "[%s]", alg);
1210 	hlen = (r <= 0) ? 0 : strlen(hash);
1211 
1212 	/* output upper border */
1213 	p = retval;
1214 	*p++ = '+';
1215 	for (i = 0; i < (FLDSIZE_X - tlen) / 2; i++)
1216 		*p++ = '-';
1217 	memcpy(p, title, tlen);
1218 	p += tlen;
1219 	for (i += tlen; i < FLDSIZE_X; i++)
1220 		*p++ = '-';
1221 	*p++ = '+';
1222 	*p++ = '\n';
1223 
1224 	/* output content */
1225 	for (y = 0; y < FLDSIZE_Y; y++) {
1226 		*p++ = '|';
1227 		for (x = 0; x < FLDSIZE_X; x++)
1228 			*p++ = augmentation_string[MINIMUM(field[x][y], len)];
1229 		*p++ = '|';
1230 		*p++ = '\n';
1231 	}
1232 
1233 	/* output lower border */
1234 	*p++ = '+';
1235 	for (i = 0; i < (FLDSIZE_X - hlen) / 2; i++)
1236 		*p++ = '-';
1237 	memcpy(p, hash, hlen);
1238 	p += hlen;
1239 	for (i += hlen; i < FLDSIZE_X; i++)
1240 		*p++ = '-';
1241 	*p++ = '+';
1242 
1243 	return retval;
1244 }
1245 
1246 char *
1247 sshkey_fingerprint(const struct sshkey *k, int dgst_alg,
1248     enum sshkey_fp_rep dgst_rep)
1249 {
1250 	char *retval = NULL;
1251 	u_char *dgst_raw;
1252 	size_t dgst_raw_len;
1253 
1254 	if (sshkey_fingerprint_raw(k, dgst_alg, &dgst_raw, &dgst_raw_len) != 0)
1255 		return NULL;
1256 	switch (dgst_rep) {
1257 	case SSH_FP_DEFAULT:
1258 		if (dgst_alg == SSH_DIGEST_MD5) {
1259 			retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg),
1260 			    dgst_raw, dgst_raw_len);
1261 		} else {
1262 			retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg),
1263 			    dgst_raw, dgst_raw_len);
1264 		}
1265 		break;
1266 	case SSH_FP_HEX:
1267 		retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg),
1268 		    dgst_raw, dgst_raw_len);
1269 		break;
1270 	case SSH_FP_BASE64:
1271 		retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg),
1272 		    dgst_raw, dgst_raw_len);
1273 		break;
1274 	case SSH_FP_BUBBLEBABBLE:
1275 		retval = fingerprint_bubblebabble(dgst_raw, dgst_raw_len);
1276 		break;
1277 	case SSH_FP_RANDOMART:
1278 		retval = fingerprint_randomart(ssh_digest_alg_name(dgst_alg),
1279 		    dgst_raw, dgst_raw_len, k);
1280 		break;
1281 	default:
1282 		explicit_bzero(dgst_raw, dgst_raw_len);
1283 		free(dgst_raw);
1284 		return NULL;
1285 	}
1286 	explicit_bzero(dgst_raw, dgst_raw_len);
1287 	free(dgst_raw);
1288 	return retval;
1289 }
1290 
1291 static int
1292 peek_type_nid(const char *s, size_t l, int *nid)
1293 {
1294 	const struct keytype *kt;
1295 
1296 	for (kt = keytypes; kt->type != -1; kt++) {
1297 		if (kt->name == NULL || strlen(kt->name) != l)
1298 			continue;
1299 		if (memcmp(s, kt->name, l) == 0) {
1300 			*nid = -1;
1301 			if (key_type_is_ecdsa_variant(kt->type))
1302 				*nid = kt->nid;
1303 			return kt->type;
1304 		}
1305 	}
1306 	return KEY_UNSPEC;
1307 }
1308 
1309 /* XXX this can now be made const char * */
1310 int
1311 sshkey_read(struct sshkey *ret, char **cpp)
1312 {
1313 	struct sshkey *k;
1314 	char *cp, *blobcopy;
1315 	size_t space;
1316 	int r, type, curve_nid = -1;
1317 	struct sshbuf *blob;
1318 
1319 	if (ret == NULL)
1320 		return SSH_ERR_INVALID_ARGUMENT;
1321 
1322 	switch (ret->type) {
1323 	case KEY_UNSPEC:
1324 	case KEY_RSA:
1325 	case KEY_DSA:
1326 	case KEY_ECDSA:
1327 	case KEY_ECDSA_SK:
1328 	case KEY_ED25519:
1329 	case KEY_ED25519_SK:
1330 	case KEY_DSA_CERT:
1331 	case KEY_ECDSA_CERT:
1332 	case KEY_ECDSA_SK_CERT:
1333 	case KEY_RSA_CERT:
1334 	case KEY_ED25519_CERT:
1335 	case KEY_ED25519_SK_CERT:
1336 #ifdef WITH_XMSS
1337 	case KEY_XMSS:
1338 	case KEY_XMSS_CERT:
1339 #endif /* WITH_XMSS */
1340 		break; /* ok */
1341 	default:
1342 		return SSH_ERR_INVALID_ARGUMENT;
1343 	}
1344 
1345 	/* Decode type */
1346 	cp = *cpp;
1347 	space = strcspn(cp, " \t");
1348 	if (space == strlen(cp))
1349 		return SSH_ERR_INVALID_FORMAT;
1350 	if ((type = peek_type_nid(cp, space, &curve_nid)) == KEY_UNSPEC)
1351 		return SSH_ERR_INVALID_FORMAT;
1352 
1353 	/* skip whitespace */
1354 	for (cp += space; *cp == ' ' || *cp == '\t'; cp++)
1355 		;
1356 	if (*cp == '\0')
1357 		return SSH_ERR_INVALID_FORMAT;
1358 	if (ret->type != KEY_UNSPEC && ret->type != type)
1359 		return SSH_ERR_KEY_TYPE_MISMATCH;
1360 	if ((blob = sshbuf_new()) == NULL)
1361 		return SSH_ERR_ALLOC_FAIL;
1362 
1363 	/* find end of keyblob and decode */
1364 	space = strcspn(cp, " \t");
1365 	if ((blobcopy = strndup(cp, space)) == NULL) {
1366 		sshbuf_free(blob);
1367 		return SSH_ERR_ALLOC_FAIL;
1368 	}
1369 	if ((r = sshbuf_b64tod(blob, blobcopy)) != 0) {
1370 		free(blobcopy);
1371 		sshbuf_free(blob);
1372 		return r;
1373 	}
1374 	free(blobcopy);
1375 	if ((r = sshkey_fromb(blob, &k)) != 0) {
1376 		sshbuf_free(blob);
1377 		return r;
1378 	}
1379 	sshbuf_free(blob);
1380 
1381 	/* skip whitespace and leave cp at start of comment */
1382 	for (cp += space; *cp == ' ' || *cp == '\t'; cp++)
1383 		;
1384 
1385 	/* ensure type of blob matches type at start of line */
1386 	if (k->type != type) {
1387 		sshkey_free(k);
1388 		return SSH_ERR_KEY_TYPE_MISMATCH;
1389 	}
1390 	if (key_type_is_ecdsa_variant(type) && curve_nid != k->ecdsa_nid) {
1391 		sshkey_free(k);
1392 		return SSH_ERR_EC_CURVE_MISMATCH;
1393 	}
1394 
1395 	/* Fill in ret from parsed key */
1396 	ret->type = type;
1397 	if (sshkey_is_cert(ret)) {
1398 		if (!sshkey_is_cert(k)) {
1399 			sshkey_free(k);
1400 			return SSH_ERR_EXPECTED_CERT;
1401 		}
1402 		if (ret->cert != NULL)
1403 			cert_free(ret->cert);
1404 		ret->cert = k->cert;
1405 		k->cert = NULL;
1406 	}
1407 	switch (sshkey_type_plain(ret->type)) {
1408 #ifdef WITH_OPENSSL
1409 	case KEY_RSA:
1410 		RSA_free(ret->rsa);
1411 		ret->rsa = k->rsa;
1412 		k->rsa = NULL;
1413 #ifdef DEBUG_PK
1414 		RSA_print_fp(stderr, ret->rsa, 8);
1415 #endif
1416 		break;
1417 	case KEY_DSA:
1418 		DSA_free(ret->dsa);
1419 		ret->dsa = k->dsa;
1420 		k->dsa = NULL;
1421 #ifdef DEBUG_PK
1422 		DSA_print_fp(stderr, ret->dsa, 8);
1423 #endif
1424 		break;
1425 # ifdef OPENSSL_HAS_ECC
1426 	case KEY_ECDSA:
1427 		EC_KEY_free(ret->ecdsa);
1428 		ret->ecdsa = k->ecdsa;
1429 		ret->ecdsa_nid = k->ecdsa_nid;
1430 		k->ecdsa = NULL;
1431 		k->ecdsa_nid = -1;
1432 #ifdef DEBUG_PK
1433 		sshkey_dump_ec_key(ret->ecdsa);
1434 #endif
1435 		break;
1436 	case KEY_ECDSA_SK:
1437 		EC_KEY_free(ret->ecdsa);
1438 		ret->ecdsa = k->ecdsa;
1439 		ret->ecdsa_nid = k->ecdsa_nid;
1440 		ret->sk_application = k->sk_application;
1441 		k->ecdsa = NULL;
1442 		k->ecdsa_nid = -1;
1443 		k->sk_application = NULL;
1444 #ifdef DEBUG_PK
1445 		sshkey_dump_ec_key(ret->ecdsa);
1446 		fprintf(stderr, "App: %s\n", ret->sk_application);
1447 #endif
1448 		break;
1449 # endif /* OPENSSL_HAS_ECC */
1450 #endif /* WITH_OPENSSL */
1451 	case KEY_ED25519:
1452 		freezero(ret->ed25519_pk, ED25519_PK_SZ);
1453 		ret->ed25519_pk = k->ed25519_pk;
1454 		k->ed25519_pk = NULL;
1455 #ifdef DEBUG_PK
1456 		/* XXX */
1457 #endif
1458 		break;
1459 	case KEY_ED25519_SK:
1460 		freezero(ret->ed25519_pk, ED25519_PK_SZ);
1461 		ret->ed25519_pk = k->ed25519_pk;
1462 		ret->sk_application = k->sk_application;
1463 		k->ed25519_pk = NULL;
1464 		k->sk_application = NULL;
1465 		break;
1466 #ifdef WITH_XMSS
1467 	case KEY_XMSS:
1468 		free(ret->xmss_pk);
1469 		ret->xmss_pk = k->xmss_pk;
1470 		k->xmss_pk = NULL;
1471 		free(ret->xmss_state);
1472 		ret->xmss_state = k->xmss_state;
1473 		k->xmss_state = NULL;
1474 		free(ret->xmss_name);
1475 		ret->xmss_name = k->xmss_name;
1476 		k->xmss_name = NULL;
1477 		free(ret->xmss_filename);
1478 		ret->xmss_filename = k->xmss_filename;
1479 		k->xmss_filename = NULL;
1480 #ifdef DEBUG_PK
1481 		/* XXX */
1482 #endif
1483 		break;
1484 #endif /* WITH_XMSS */
1485 	default:
1486 		sshkey_free(k);
1487 		return SSH_ERR_INTERNAL_ERROR;
1488 	}
1489 	sshkey_free(k);
1490 
1491 	/* success */
1492 	*cpp = cp;
1493 	return 0;
1494 }
1495 
1496 
1497 int
1498 sshkey_to_base64(const struct sshkey *key, char **b64p)
1499 {
1500 	int r = SSH_ERR_INTERNAL_ERROR;
1501 	struct sshbuf *b = NULL;
1502 	char *uu = NULL;
1503 
1504 	if (b64p != NULL)
1505 		*b64p = NULL;
1506 	if ((b = sshbuf_new()) == NULL)
1507 		return SSH_ERR_ALLOC_FAIL;
1508 	if ((r = sshkey_putb(key, b)) != 0)
1509 		goto out;
1510 	if ((uu = sshbuf_dtob64_string(b, 0)) == NULL) {
1511 		r = SSH_ERR_ALLOC_FAIL;
1512 		goto out;
1513 	}
1514 	/* Success */
1515 	if (b64p != NULL) {
1516 		*b64p = uu;
1517 		uu = NULL;
1518 	}
1519 	r = 0;
1520  out:
1521 	sshbuf_free(b);
1522 	free(uu);
1523 	return r;
1524 }
1525 
1526 int
1527 sshkey_format_text(const struct sshkey *key, struct sshbuf *b)
1528 {
1529 	int r = SSH_ERR_INTERNAL_ERROR;
1530 	char *uu = NULL;
1531 
1532 	if ((r = sshkey_to_base64(key, &uu)) != 0)
1533 		goto out;
1534 	if ((r = sshbuf_putf(b, "%s %s",
1535 	    sshkey_ssh_name(key), uu)) != 0)
1536 		goto out;
1537 	r = 0;
1538  out:
1539 	free(uu);
1540 	return r;
1541 }
1542 
1543 int
1544 sshkey_write(const struct sshkey *key, FILE *f)
1545 {
1546 	struct sshbuf *b = NULL;
1547 	int r = SSH_ERR_INTERNAL_ERROR;
1548 
1549 	if ((b = sshbuf_new()) == NULL)
1550 		return SSH_ERR_ALLOC_FAIL;
1551 	if ((r = sshkey_format_text(key, b)) != 0)
1552 		goto out;
1553 	if (fwrite(sshbuf_ptr(b), sshbuf_len(b), 1, f) != 1) {
1554 		if (feof(f))
1555 			errno = EPIPE;
1556 		r = SSH_ERR_SYSTEM_ERROR;
1557 		goto out;
1558 	}
1559 	/* Success */
1560 	r = 0;
1561  out:
1562 	sshbuf_free(b);
1563 	return r;
1564 }
1565 
1566 const char *
1567 sshkey_cert_type(const struct sshkey *k)
1568 {
1569 	switch (k->cert->type) {
1570 	case SSH2_CERT_TYPE_USER:
1571 		return "user";
1572 	case SSH2_CERT_TYPE_HOST:
1573 		return "host";
1574 	default:
1575 		return "unknown";
1576 	}
1577 }
1578 
1579 #ifdef WITH_OPENSSL
1580 static int
1581 rsa_generate_private_key(u_int bits, RSA **rsap)
1582 {
1583 	RSA *private = NULL;
1584 	BIGNUM *f4 = NULL;
1585 	int ret = SSH_ERR_INTERNAL_ERROR;
1586 
1587 	if (rsap == NULL)
1588 		return SSH_ERR_INVALID_ARGUMENT;
1589 	if (bits < SSH_RSA_MINIMUM_MODULUS_SIZE ||
1590 	    bits > SSHBUF_MAX_BIGNUM * 8)
1591 		return SSH_ERR_KEY_LENGTH;
1592 	*rsap = NULL;
1593 	if ((private = RSA_new()) == NULL || (f4 = BN_new()) == NULL) {
1594 		ret = SSH_ERR_ALLOC_FAIL;
1595 		goto out;
1596 	}
1597 	if (!BN_set_word(f4, RSA_F4) ||
1598 	    !RSA_generate_key_ex(private, bits, f4, NULL)) {
1599 		ret = SSH_ERR_LIBCRYPTO_ERROR;
1600 		goto out;
1601 	}
1602 	*rsap = private;
1603 	private = NULL;
1604 	ret = 0;
1605  out:
1606 	RSA_free(private);
1607 	BN_free(f4);
1608 	return ret;
1609 }
1610 
1611 static int
1612 dsa_generate_private_key(u_int bits, DSA **dsap)
1613 {
1614 	DSA *private;
1615 	int ret = SSH_ERR_INTERNAL_ERROR;
1616 
1617 	if (dsap == NULL)
1618 		return SSH_ERR_INVALID_ARGUMENT;
1619 	if (bits != 1024)
1620 		return SSH_ERR_KEY_LENGTH;
1621 	if ((private = DSA_new()) == NULL) {
1622 		ret = SSH_ERR_ALLOC_FAIL;
1623 		goto out;
1624 	}
1625 	*dsap = NULL;
1626 	if (!DSA_generate_parameters_ex(private, bits, NULL, 0, NULL,
1627 	    NULL, NULL) || !DSA_generate_key(private)) {
1628 		ret = SSH_ERR_LIBCRYPTO_ERROR;
1629 		goto out;
1630 	}
1631 	*dsap = private;
1632 	private = NULL;
1633 	ret = 0;
1634  out:
1635 	DSA_free(private);
1636 	return ret;
1637 }
1638 
1639 # ifdef OPENSSL_HAS_ECC
1640 int
1641 sshkey_ecdsa_key_to_nid(EC_KEY *k)
1642 {
1643 	EC_GROUP *eg;
1644 	int nids[] = {
1645 		NID_X9_62_prime256v1,
1646 		NID_secp384r1,
1647 #  ifdef OPENSSL_HAS_NISTP521
1648 		NID_secp521r1,
1649 #  endif /* OPENSSL_HAS_NISTP521 */
1650 		-1
1651 	};
1652 	int nid;
1653 	u_int i;
1654 	const EC_GROUP *g = EC_KEY_get0_group(k);
1655 
1656 	/*
1657 	 * The group may be stored in a ASN.1 encoded private key in one of two
1658 	 * ways: as a "named group", which is reconstituted by ASN.1 object ID
1659 	 * or explicit group parameters encoded into the key blob. Only the
1660 	 * "named group" case sets the group NID for us, but we can figure
1661 	 * it out for the other case by comparing against all the groups that
1662 	 * are supported.
1663 	 */
1664 	if ((nid = EC_GROUP_get_curve_name(g)) > 0)
1665 		return nid;
1666 	for (i = 0; nids[i] != -1; i++) {
1667 		if ((eg = EC_GROUP_new_by_curve_name(nids[i])) == NULL)
1668 			return -1;
1669 		if (EC_GROUP_cmp(g, eg, NULL) == 0)
1670 			break;
1671 		EC_GROUP_free(eg);
1672 	}
1673 	if (nids[i] != -1) {
1674 		/* Use the group with the NID attached */
1675 		EC_GROUP_set_asn1_flag(eg, OPENSSL_EC_NAMED_CURVE);
1676 		if (EC_KEY_set_group(k, eg) != 1) {
1677 			EC_GROUP_free(eg);
1678 			return -1;
1679 		}
1680 	}
1681 	return nids[i];
1682 }
1683 
1684 static int
1685 ecdsa_generate_private_key(u_int bits, int *nid, EC_KEY **ecdsap)
1686 {
1687 	EC_KEY *private;
1688 	int ret = SSH_ERR_INTERNAL_ERROR;
1689 
1690 	if (nid == NULL || ecdsap == NULL)
1691 		return SSH_ERR_INVALID_ARGUMENT;
1692 	if ((*nid = sshkey_ecdsa_bits_to_nid(bits)) == -1)
1693 		return SSH_ERR_KEY_LENGTH;
1694 	*ecdsap = NULL;
1695 	if ((private = EC_KEY_new_by_curve_name(*nid)) == NULL) {
1696 		ret = SSH_ERR_ALLOC_FAIL;
1697 		goto out;
1698 	}
1699 	if (EC_KEY_generate_key(private) != 1) {
1700 		ret = SSH_ERR_LIBCRYPTO_ERROR;
1701 		goto out;
1702 	}
1703 	EC_KEY_set_asn1_flag(private, OPENSSL_EC_NAMED_CURVE);
1704 	*ecdsap = private;
1705 	private = NULL;
1706 	ret = 0;
1707  out:
1708 	EC_KEY_free(private);
1709 	return ret;
1710 }
1711 # endif /* OPENSSL_HAS_ECC */
1712 #endif /* WITH_OPENSSL */
1713 
1714 int
1715 sshkey_generate(int type, u_int bits, struct sshkey **keyp)
1716 {
1717 	struct sshkey *k;
1718 	int ret = SSH_ERR_INTERNAL_ERROR;
1719 
1720 	if (keyp == NULL)
1721 		return SSH_ERR_INVALID_ARGUMENT;
1722 	*keyp = NULL;
1723 	if ((k = sshkey_new(KEY_UNSPEC)) == NULL)
1724 		return SSH_ERR_ALLOC_FAIL;
1725 	switch (type) {
1726 	case KEY_ED25519:
1727 		if ((k->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL ||
1728 		    (k->ed25519_sk = malloc(ED25519_SK_SZ)) == NULL) {
1729 			ret = SSH_ERR_ALLOC_FAIL;
1730 			break;
1731 		}
1732 		crypto_sign_ed25519_keypair(k->ed25519_pk, k->ed25519_sk);
1733 		ret = 0;
1734 		break;
1735 #ifdef WITH_XMSS
1736 	case KEY_XMSS:
1737 		ret = sshkey_xmss_generate_private_key(k, bits);
1738 		break;
1739 #endif /* WITH_XMSS */
1740 #ifdef WITH_OPENSSL
1741 	case KEY_DSA:
1742 		ret = dsa_generate_private_key(bits, &k->dsa);
1743 		break;
1744 # ifdef OPENSSL_HAS_ECC
1745 	case KEY_ECDSA:
1746 		ret = ecdsa_generate_private_key(bits, &k->ecdsa_nid,
1747 		    &k->ecdsa);
1748 		break;
1749 # endif /* OPENSSL_HAS_ECC */
1750 	case KEY_RSA:
1751 		ret = rsa_generate_private_key(bits, &k->rsa);
1752 		break;
1753 #endif /* WITH_OPENSSL */
1754 	default:
1755 		ret = SSH_ERR_INVALID_ARGUMENT;
1756 	}
1757 	if (ret == 0) {
1758 		k->type = type;
1759 		*keyp = k;
1760 	} else
1761 		sshkey_free(k);
1762 	return ret;
1763 }
1764 
1765 int
1766 sshkey_cert_copy(const struct sshkey *from_key, struct sshkey *to_key)
1767 {
1768 	u_int i;
1769 	const struct sshkey_cert *from;
1770 	struct sshkey_cert *to;
1771 	int r = SSH_ERR_INTERNAL_ERROR;
1772 
1773 	if (to_key == NULL || (from = from_key->cert) == NULL)
1774 		return SSH_ERR_INVALID_ARGUMENT;
1775 
1776 	if ((to = cert_new()) == NULL)
1777 		return SSH_ERR_ALLOC_FAIL;
1778 
1779 	if ((r = sshbuf_putb(to->certblob, from->certblob)) != 0 ||
1780 	    (r = sshbuf_putb(to->critical, from->critical)) != 0 ||
1781 	    (r = sshbuf_putb(to->extensions, from->extensions)) != 0)
1782 		goto out;
1783 
1784 	to->serial = from->serial;
1785 	to->type = from->type;
1786 	if (from->key_id == NULL)
1787 		to->key_id = NULL;
1788 	else if ((to->key_id = strdup(from->key_id)) == NULL) {
1789 		r = SSH_ERR_ALLOC_FAIL;
1790 		goto out;
1791 	}
1792 	to->valid_after = from->valid_after;
1793 	to->valid_before = from->valid_before;
1794 	if (from->signature_key == NULL)
1795 		to->signature_key = NULL;
1796 	else if ((r = sshkey_from_private(from->signature_key,
1797 	    &to->signature_key)) != 0)
1798 		goto out;
1799 	if (from->signature_type != NULL &&
1800 	    (to->signature_type = strdup(from->signature_type)) == NULL) {
1801 		r = SSH_ERR_ALLOC_FAIL;
1802 		goto out;
1803 	}
1804 	if (from->nprincipals > SSHKEY_CERT_MAX_PRINCIPALS) {
1805 		r = SSH_ERR_INVALID_ARGUMENT;
1806 		goto out;
1807 	}
1808 	if (from->nprincipals > 0) {
1809 		if ((to->principals = calloc(from->nprincipals,
1810 		    sizeof(*to->principals))) == NULL) {
1811 			r = SSH_ERR_ALLOC_FAIL;
1812 			goto out;
1813 		}
1814 		for (i = 0; i < from->nprincipals; i++) {
1815 			to->principals[i] = strdup(from->principals[i]);
1816 			if (to->principals[i] == NULL) {
1817 				to->nprincipals = i;
1818 				r = SSH_ERR_ALLOC_FAIL;
1819 				goto out;
1820 			}
1821 		}
1822 	}
1823 	to->nprincipals = from->nprincipals;
1824 
1825 	/* success */
1826 	cert_free(to_key->cert);
1827 	to_key->cert = to;
1828 	to = NULL;
1829 	r = 0;
1830  out:
1831 	cert_free(to);
1832 	return r;
1833 }
1834 
1835 int
1836 sshkey_from_private(const struct sshkey *k, struct sshkey **pkp)
1837 {
1838 	struct sshkey *n = NULL;
1839 	int r = SSH_ERR_INTERNAL_ERROR;
1840 #ifdef WITH_OPENSSL
1841 	const BIGNUM *rsa_n, *rsa_e;
1842 	BIGNUM *rsa_n_dup = NULL, *rsa_e_dup = NULL;
1843 	const BIGNUM *dsa_p, *dsa_q, *dsa_g, *dsa_pub_key;
1844 	BIGNUM *dsa_p_dup = NULL, *dsa_q_dup = NULL, *dsa_g_dup = NULL;
1845 	BIGNUM *dsa_pub_key_dup = NULL;
1846 #endif /* WITH_OPENSSL */
1847 
1848 	*pkp = NULL;
1849 	if ((n = sshkey_new(k->type)) == NULL) {
1850 		r = SSH_ERR_ALLOC_FAIL;
1851 		goto out;
1852 	}
1853 	switch (k->type) {
1854 #ifdef WITH_OPENSSL
1855 	case KEY_DSA:
1856 	case KEY_DSA_CERT:
1857 		DSA_get0_pqg(k->dsa, &dsa_p, &dsa_q, &dsa_g);
1858 		DSA_get0_key(k->dsa, &dsa_pub_key, NULL);
1859 		if ((dsa_p_dup = BN_dup(dsa_p)) == NULL ||
1860 		    (dsa_q_dup = BN_dup(dsa_q)) == NULL ||
1861 		    (dsa_g_dup = BN_dup(dsa_g)) == NULL ||
1862 		    (dsa_pub_key_dup = BN_dup(dsa_pub_key)) == NULL) {
1863 			r = SSH_ERR_ALLOC_FAIL;
1864 			goto out;
1865 		}
1866 		if (!DSA_set0_pqg(n->dsa, dsa_p_dup, dsa_q_dup, dsa_g_dup)) {
1867 			r = SSH_ERR_LIBCRYPTO_ERROR;
1868 			goto out;
1869 		}
1870 		dsa_p_dup = dsa_q_dup = dsa_g_dup = NULL; /* transferred */
1871 		if (!DSA_set0_key(n->dsa, dsa_pub_key_dup, NULL)) {
1872 			r = SSH_ERR_LIBCRYPTO_ERROR;
1873 			goto out;
1874 		}
1875 		dsa_pub_key_dup = NULL; /* transferred */
1876 
1877 		break;
1878 # ifdef OPENSSL_HAS_ECC
1879 	case KEY_ECDSA:
1880 	case KEY_ECDSA_CERT:
1881 	case KEY_ECDSA_SK:
1882 	case KEY_ECDSA_SK_CERT:
1883 		n->ecdsa_nid = k->ecdsa_nid;
1884 		n->ecdsa = EC_KEY_new_by_curve_name(k->ecdsa_nid);
1885 		if (n->ecdsa == NULL) {
1886 			r = SSH_ERR_ALLOC_FAIL;
1887 			goto out;
1888 		}
1889 		if (EC_KEY_set_public_key(n->ecdsa,
1890 		    EC_KEY_get0_public_key(k->ecdsa)) != 1) {
1891 			r = SSH_ERR_LIBCRYPTO_ERROR;
1892 			goto out;
1893 		}
1894 		if (k->type != KEY_ECDSA_SK && k->type != KEY_ECDSA_SK_CERT)
1895 			break;
1896 		/* Append security-key application string */
1897 		if ((n->sk_application = strdup(k->sk_application)) == NULL)
1898 			goto out;
1899 		break;
1900 # endif /* OPENSSL_HAS_ECC */
1901 	case KEY_RSA:
1902 	case KEY_RSA_CERT:
1903 		RSA_get0_key(k->rsa, &rsa_n, &rsa_e, NULL);
1904 		if ((rsa_n_dup = BN_dup(rsa_n)) == NULL ||
1905 		    (rsa_e_dup = BN_dup(rsa_e)) == NULL) {
1906 			r = SSH_ERR_ALLOC_FAIL;
1907 			goto out;
1908 		}
1909 		if (!RSA_set0_key(n->rsa, rsa_n_dup, rsa_e_dup, NULL)) {
1910 			r = SSH_ERR_LIBCRYPTO_ERROR;
1911 			goto out;
1912 		}
1913 		rsa_n_dup = rsa_e_dup = NULL; /* transferred */
1914 		break;
1915 #endif /* WITH_OPENSSL */
1916 	case KEY_ED25519:
1917 	case KEY_ED25519_CERT:
1918 	case KEY_ED25519_SK:
1919 	case KEY_ED25519_SK_CERT:
1920 		if (k->ed25519_pk != NULL) {
1921 			if ((n->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL) {
1922 				r = SSH_ERR_ALLOC_FAIL;
1923 				goto out;
1924 			}
1925 			memcpy(n->ed25519_pk, k->ed25519_pk, ED25519_PK_SZ);
1926 		}
1927 		if (k->type != KEY_ED25519_SK &&
1928 		    k->type != KEY_ED25519_SK_CERT)
1929 			break;
1930 		/* Append security-key application string */
1931 		if ((n->sk_application = strdup(k->sk_application)) == NULL)
1932 			goto out;
1933 		break;
1934 #ifdef WITH_XMSS
1935 	case KEY_XMSS:
1936 	case KEY_XMSS_CERT:
1937 		if ((r = sshkey_xmss_init(n, k->xmss_name)) != 0)
1938 			goto out;
1939 		if (k->xmss_pk != NULL) {
1940 			u_int32_t left;
1941 			size_t pklen = sshkey_xmss_pklen(k);
1942 			if (pklen == 0 || sshkey_xmss_pklen(n) != pklen) {
1943 				r = SSH_ERR_INTERNAL_ERROR;
1944 				goto out;
1945 			}
1946 			if ((n->xmss_pk = malloc(pklen)) == NULL) {
1947 				r = SSH_ERR_ALLOC_FAIL;
1948 				goto out;
1949 			}
1950 			memcpy(n->xmss_pk, k->xmss_pk, pklen);
1951 			/* simulate number of signatures left on pubkey */
1952 			left = sshkey_xmss_signatures_left(k);
1953 			if (left)
1954 				sshkey_xmss_enable_maxsign(n, left);
1955 		}
1956 		break;
1957 #endif /* WITH_XMSS */
1958 	default:
1959 		r = SSH_ERR_KEY_TYPE_UNKNOWN;
1960 		goto out;
1961 	}
1962 	if (sshkey_is_cert(k) && (r = sshkey_cert_copy(k, n)) != 0)
1963 		goto out;
1964 	/* success */
1965 	*pkp = n;
1966 	n = NULL;
1967 	r = 0;
1968  out:
1969 	sshkey_free(n);
1970 #ifdef WITH_OPENSSL
1971 	BN_clear_free(rsa_n_dup);
1972 	BN_clear_free(rsa_e_dup);
1973 	BN_clear_free(dsa_p_dup);
1974 	BN_clear_free(dsa_q_dup);
1975 	BN_clear_free(dsa_g_dup);
1976 	BN_clear_free(dsa_pub_key_dup);
1977 #endif
1978 
1979 	return r;
1980 }
1981 
1982 int
1983 sshkey_is_shielded(struct sshkey *k)
1984 {
1985 	return k != NULL && k->shielded_private != NULL;
1986 }
1987 
1988 int
1989 sshkey_shield_private(struct sshkey *k)
1990 {
1991 	struct sshbuf *prvbuf = NULL;
1992 	u_char *prekey = NULL, *enc = NULL, keyiv[SSH_DIGEST_MAX_LENGTH];
1993 	struct sshcipher_ctx *cctx = NULL;
1994 	const struct sshcipher *cipher;
1995 	size_t i, enclen = 0;
1996 	struct sshkey *kswap = NULL, tmp;
1997 	int r = SSH_ERR_INTERNAL_ERROR;
1998 
1999 #ifdef DEBUG_PK
2000 	fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k));
2001 #endif
2002 	if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) {
2003 		r = SSH_ERR_INVALID_ARGUMENT;
2004 		goto out;
2005 	}
2006 	if (cipher_keylen(cipher) + cipher_ivlen(cipher) >
2007 	    ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) {
2008 		r = SSH_ERR_INTERNAL_ERROR;
2009 		goto out;
2010 	}
2011 
2012 	/* Prepare a random pre-key, and from it an ephemeral key */
2013 	if ((prekey = malloc(SSHKEY_SHIELD_PREKEY_LEN)) == NULL) {
2014 		r = SSH_ERR_ALLOC_FAIL;
2015 		goto out;
2016 	}
2017 	arc4random_buf(prekey, SSHKEY_SHIELD_PREKEY_LEN);
2018 	if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH,
2019 	    prekey, SSHKEY_SHIELD_PREKEY_LEN,
2020 	    keyiv, SSH_DIGEST_MAX_LENGTH)) != 0)
2021 		goto out;
2022 #ifdef DEBUG_PK
2023 	fprintf(stderr, "%s: key+iv\n", __func__);
2024 	sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH),
2025 	    stderr);
2026 #endif
2027 	if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher),
2028 	    keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 1)) != 0)
2029 		goto out;
2030 
2031 	/* Serialise and encrypt the private key using the ephemeral key */
2032 	if ((prvbuf = sshbuf_new()) == NULL) {
2033 		r = SSH_ERR_ALLOC_FAIL;
2034 		goto out;
2035 	}
2036 	if (sshkey_is_shielded(k) && (r = sshkey_unshield_private(k)) != 0)
2037 		goto out;
2038 	if ((r = sshkey_private_serialize_opt(k, prvbuf,
2039 	     SSHKEY_SERIALIZE_SHIELD)) != 0)
2040 		goto out;
2041 	/* pad to cipher blocksize */
2042 	i = 0;
2043 	while (sshbuf_len(prvbuf) % cipher_blocksize(cipher)) {
2044 		if ((r = sshbuf_put_u8(prvbuf, ++i & 0xff)) != 0)
2045 			goto out;
2046 	}
2047 #ifdef DEBUG_PK
2048 	fprintf(stderr, "%s: serialised\n", __func__);
2049 	sshbuf_dump(prvbuf, stderr);
2050 #endif
2051 	/* encrypt */
2052 	enclen = sshbuf_len(prvbuf);
2053 	if ((enc = malloc(enclen)) == NULL) {
2054 		r = SSH_ERR_ALLOC_FAIL;
2055 		goto out;
2056 	}
2057 	if ((r = cipher_crypt(cctx, 0, enc,
2058 	    sshbuf_ptr(prvbuf), sshbuf_len(prvbuf), 0, 0)) != 0)
2059 		goto out;
2060 #ifdef DEBUG_PK
2061 	fprintf(stderr, "%s: encrypted\n", __func__);
2062 	sshbuf_dump_data(enc, enclen, stderr);
2063 #endif
2064 
2065 	/* Make a scrubbed, public-only copy of our private key argument */
2066 	if ((r = sshkey_from_private(k, &kswap)) != 0)
2067 		goto out;
2068 
2069 	/* Swap the private key out (it will be destroyed below) */
2070 	tmp = *kswap;
2071 	*kswap = *k;
2072 	*k = tmp;
2073 
2074 	/* Insert the shielded key into our argument */
2075 	k->shielded_private = enc;
2076 	k->shielded_len = enclen;
2077 	k->shield_prekey = prekey;
2078 	k->shield_prekey_len = SSHKEY_SHIELD_PREKEY_LEN;
2079 	enc = prekey = NULL; /* transferred */
2080 	enclen = 0;
2081 
2082 	/* success */
2083 	r = 0;
2084 
2085  out:
2086 	/* XXX behaviour on error - invalidate original private key? */
2087 	cipher_free(cctx);
2088 	explicit_bzero(keyiv, sizeof(keyiv));
2089 	explicit_bzero(&tmp, sizeof(tmp));
2090 	freezero(enc, enclen);
2091 	freezero(prekey, SSHKEY_SHIELD_PREKEY_LEN);
2092 	sshkey_free(kswap);
2093 	sshbuf_free(prvbuf);
2094 	return r;
2095 }
2096 
2097 int
2098 sshkey_unshield_private(struct sshkey *k)
2099 {
2100 	struct sshbuf *prvbuf = NULL;
2101 	u_char pad, *cp, keyiv[SSH_DIGEST_MAX_LENGTH];
2102 	struct sshcipher_ctx *cctx = NULL;
2103 	const struct sshcipher *cipher;
2104 	size_t i;
2105 	struct sshkey *kswap = NULL, tmp;
2106 	int r = SSH_ERR_INTERNAL_ERROR;
2107 
2108 #ifdef DEBUG_PK
2109 	fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k));
2110 #endif
2111 	if (!sshkey_is_shielded(k))
2112 		return 0; /* nothing to do */
2113 
2114 	if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) {
2115 		r = SSH_ERR_INVALID_ARGUMENT;
2116 		goto out;
2117 	}
2118 	if (cipher_keylen(cipher) + cipher_ivlen(cipher) >
2119 	    ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) {
2120 		r = SSH_ERR_INTERNAL_ERROR;
2121 		goto out;
2122 	}
2123 	/* check size of shielded key blob */
2124 	if (k->shielded_len < cipher_blocksize(cipher) ||
2125 	    (k->shielded_len % cipher_blocksize(cipher)) != 0) {
2126 		r = SSH_ERR_INVALID_FORMAT;
2127 		goto out;
2128 	}
2129 
2130 	/* Calculate the ephemeral key from the prekey */
2131 	if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH,
2132 	    k->shield_prekey, k->shield_prekey_len,
2133 	    keyiv, SSH_DIGEST_MAX_LENGTH)) != 0)
2134 		goto out;
2135 	if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher),
2136 	    keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 0)) != 0)
2137 		goto out;
2138 #ifdef DEBUG_PK
2139 	fprintf(stderr, "%s: key+iv\n", __func__);
2140 	sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH),
2141 	    stderr);
2142 #endif
2143 
2144 	/* Decrypt and parse the shielded private key using the ephemeral key */
2145 	if ((prvbuf = sshbuf_new()) == NULL) {
2146 		r = SSH_ERR_ALLOC_FAIL;
2147 		goto out;
2148 	}
2149 	if ((r = sshbuf_reserve(prvbuf, k->shielded_len, &cp)) != 0)
2150 		goto out;
2151 	/* decrypt */
2152 #ifdef DEBUG_PK
2153 	fprintf(stderr, "%s: encrypted\n", __func__);
2154 	sshbuf_dump_data(k->shielded_private, k->shielded_len, stderr);
2155 #endif
2156 	if ((r = cipher_crypt(cctx, 0, cp,
2157 	    k->shielded_private, k->shielded_len, 0, 0)) != 0)
2158 		goto out;
2159 #ifdef DEBUG_PK
2160 	fprintf(stderr, "%s: serialised\n", __func__);
2161 	sshbuf_dump(prvbuf, stderr);
2162 #endif
2163 	/* Parse private key */
2164 	if ((r = sshkey_private_deserialize(prvbuf, &kswap)) != 0)
2165 		goto out;
2166 	/* Check deterministic padding */
2167 	i = 0;
2168 	while (sshbuf_len(prvbuf)) {
2169 		if ((r = sshbuf_get_u8(prvbuf, &pad)) != 0)
2170 			goto out;
2171 		if (pad != (++i & 0xff)) {
2172 			r = SSH_ERR_INVALID_FORMAT;
2173 			goto out;
2174 		}
2175 	}
2176 
2177 	/* Swap the parsed key back into place */
2178 	tmp = *kswap;
2179 	*kswap = *k;
2180 	*k = tmp;
2181 
2182 	/* success */
2183 	r = 0;
2184 
2185  out:
2186 	cipher_free(cctx);
2187 	explicit_bzero(keyiv, sizeof(keyiv));
2188 	explicit_bzero(&tmp, sizeof(tmp));
2189 	sshkey_free(kswap);
2190 	sshbuf_free(prvbuf);
2191 	return r;
2192 }
2193 
2194 static int
2195 cert_parse(struct sshbuf *b, struct sshkey *key, struct sshbuf *certbuf)
2196 {
2197 	struct sshbuf *principals = NULL, *crit = NULL;
2198 	struct sshbuf *exts = NULL, *ca = NULL;
2199 	u_char *sig = NULL;
2200 	size_t signed_len = 0, slen = 0, kidlen = 0;
2201 	int ret = SSH_ERR_INTERNAL_ERROR;
2202 
2203 	/* Copy the entire key blob for verification and later serialisation */
2204 	if ((ret = sshbuf_putb(key->cert->certblob, certbuf)) != 0)
2205 		return ret;
2206 
2207 	/* Parse body of certificate up to signature */
2208 	if ((ret = sshbuf_get_u64(b, &key->cert->serial)) != 0 ||
2209 	    (ret = sshbuf_get_u32(b, &key->cert->type)) != 0 ||
2210 	    (ret = sshbuf_get_cstring(b, &key->cert->key_id, &kidlen)) != 0 ||
2211 	    (ret = sshbuf_froms(b, &principals)) != 0 ||
2212 	    (ret = sshbuf_get_u64(b, &key->cert->valid_after)) != 0 ||
2213 	    (ret = sshbuf_get_u64(b, &key->cert->valid_before)) != 0 ||
2214 	    (ret = sshbuf_froms(b, &crit)) != 0 ||
2215 	    (ret = sshbuf_froms(b, &exts)) != 0 ||
2216 	    (ret = sshbuf_get_string_direct(b, NULL, NULL)) != 0 ||
2217 	    (ret = sshbuf_froms(b, &ca)) != 0) {
2218 		/* XXX debug print error for ret */
2219 		ret = SSH_ERR_INVALID_FORMAT;
2220 		goto out;
2221 	}
2222 
2223 	/* Signature is left in the buffer so we can calculate this length */
2224 	signed_len = sshbuf_len(key->cert->certblob) - sshbuf_len(b);
2225 
2226 	if ((ret = sshbuf_get_string(b, &sig, &slen)) != 0) {
2227 		ret = SSH_ERR_INVALID_FORMAT;
2228 		goto out;
2229 	}
2230 
2231 	if (key->cert->type != SSH2_CERT_TYPE_USER &&
2232 	    key->cert->type != SSH2_CERT_TYPE_HOST) {
2233 		ret = SSH_ERR_KEY_CERT_UNKNOWN_TYPE;
2234 		goto out;
2235 	}
2236 
2237 	/* Parse principals section */
2238 	while (sshbuf_len(principals) > 0) {
2239 		char *principal = NULL;
2240 		char **oprincipals = NULL;
2241 
2242 		if (key->cert->nprincipals >= SSHKEY_CERT_MAX_PRINCIPALS) {
2243 			ret = SSH_ERR_INVALID_FORMAT;
2244 			goto out;
2245 		}
2246 		if ((ret = sshbuf_get_cstring(principals, &principal,
2247 		    NULL)) != 0) {
2248 			ret = SSH_ERR_INVALID_FORMAT;
2249 			goto out;
2250 		}
2251 		oprincipals = key->cert->principals;
2252 		key->cert->principals = recallocarray(key->cert->principals,
2253 		    key->cert->nprincipals, key->cert->nprincipals + 1,
2254 		    sizeof(*key->cert->principals));
2255 		if (key->cert->principals == NULL) {
2256 			free(principal);
2257 			key->cert->principals = oprincipals;
2258 			ret = SSH_ERR_ALLOC_FAIL;
2259 			goto out;
2260 		}
2261 		key->cert->principals[key->cert->nprincipals++] = principal;
2262 	}
2263 
2264 	/*
2265 	 * Stash a copies of the critical options and extensions sections
2266 	 * for later use.
2267 	 */
2268 	if ((ret = sshbuf_putb(key->cert->critical, crit)) != 0 ||
2269 	    (exts != NULL &&
2270 	    (ret = sshbuf_putb(key->cert->extensions, exts)) != 0))
2271 		goto out;
2272 
2273 	/*
2274 	 * Validate critical options and extensions sections format.
2275 	 */
2276 	while (sshbuf_len(crit) != 0) {
2277 		if ((ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0 ||
2278 		    (ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0) {
2279 			sshbuf_reset(key->cert->critical);
2280 			ret = SSH_ERR_INVALID_FORMAT;
2281 			goto out;
2282 		}
2283 	}
2284 	while (exts != NULL && sshbuf_len(exts) != 0) {
2285 		if ((ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0 ||
2286 		    (ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0) {
2287 			sshbuf_reset(key->cert->extensions);
2288 			ret = SSH_ERR_INVALID_FORMAT;
2289 			goto out;
2290 		}
2291 	}
2292 
2293 	/* Parse CA key and check signature */
2294 	if (sshkey_from_blob_internal(ca, &key->cert->signature_key, 0) != 0) {
2295 		ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
2296 		goto out;
2297 	}
2298 	if (!sshkey_type_is_valid_ca(key->cert->signature_key->type)) {
2299 		ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
2300 		goto out;
2301 	}
2302 	if ((ret = sshkey_verify(key->cert->signature_key, sig, slen,
2303 	    sshbuf_ptr(key->cert->certblob), signed_len, NULL, 0)) != 0)
2304 		goto out;
2305 	if ((ret = sshkey_get_sigtype(sig, slen,
2306 	    &key->cert->signature_type)) != 0)
2307 		goto out;
2308 
2309 	/* Success */
2310 	ret = 0;
2311  out:
2312 	sshbuf_free(ca);
2313 	sshbuf_free(crit);
2314 	sshbuf_free(exts);
2315 	sshbuf_free(principals);
2316 	free(sig);
2317 	return ret;
2318 }
2319 
2320 #ifdef WITH_OPENSSL
2321 static int
2322 check_rsa_length(const RSA *rsa)
2323 {
2324 	const BIGNUM *rsa_n;
2325 
2326 	RSA_get0_key(rsa, &rsa_n, NULL, NULL);
2327 	if (BN_num_bits(rsa_n) < SSH_RSA_MINIMUM_MODULUS_SIZE)
2328 		return SSH_ERR_KEY_LENGTH;
2329 	return 0;
2330 }
2331 #endif
2332 
2333 static int
2334 sshkey_from_blob_internal(struct sshbuf *b, struct sshkey **keyp,
2335     int allow_cert)
2336 {
2337 	int type, ret = SSH_ERR_INTERNAL_ERROR;
2338 	char *ktype = NULL, *curve = NULL, *xmss_name = NULL;
2339 	struct sshkey *key = NULL;
2340 	size_t len;
2341 	u_char *pk = NULL;
2342 	struct sshbuf *copy;
2343 #if defined(WITH_OPENSSL)
2344 	BIGNUM *rsa_n = NULL, *rsa_e = NULL;
2345 	BIGNUM *dsa_p = NULL, *dsa_q = NULL, *dsa_g = NULL, *dsa_pub_key = NULL;
2346 # if defined(OPENSSL_HAS_ECC)
2347 	EC_POINT *q = NULL;
2348 # endif /* OPENSSL_HAS_ECC */
2349 #endif /* WITH_OPENSSL */
2350 
2351 #ifdef DEBUG_PK /* XXX */
2352 	sshbuf_dump(b, stderr);
2353 #endif
2354 	if (keyp != NULL)
2355 		*keyp = NULL;
2356 	if ((copy = sshbuf_fromb(b)) == NULL) {
2357 		ret = SSH_ERR_ALLOC_FAIL;
2358 		goto out;
2359 	}
2360 	if (sshbuf_get_cstring(b, &ktype, NULL) != 0) {
2361 		ret = SSH_ERR_INVALID_FORMAT;
2362 		goto out;
2363 	}
2364 
2365 	type = sshkey_type_from_name(ktype);
2366 	if (!allow_cert && sshkey_type_is_cert(type)) {
2367 		ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
2368 		goto out;
2369 	}
2370 	switch (type) {
2371 #ifdef WITH_OPENSSL
2372 	case KEY_RSA_CERT:
2373 		/* Skip nonce */
2374 		if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
2375 			ret = SSH_ERR_INVALID_FORMAT;
2376 			goto out;
2377 		}
2378 		/* FALLTHROUGH */
2379 	case KEY_RSA:
2380 		if ((key = sshkey_new(type)) == NULL) {
2381 			ret = SSH_ERR_ALLOC_FAIL;
2382 			goto out;
2383 		}
2384 		if (sshbuf_get_bignum2(b, &rsa_e) != 0 ||
2385 		    sshbuf_get_bignum2(b, &rsa_n) != 0) {
2386 			ret = SSH_ERR_INVALID_FORMAT;
2387 			goto out;
2388 		}
2389 		if (!RSA_set0_key(key->rsa, rsa_n, rsa_e, NULL)) {
2390 			ret = SSH_ERR_LIBCRYPTO_ERROR;
2391 			goto out;
2392 		}
2393 		rsa_n = rsa_e = NULL; /* transferred */
2394 		if ((ret = check_rsa_length(key->rsa)) != 0)
2395 			goto out;
2396 #ifdef DEBUG_PK
2397 		RSA_print_fp(stderr, key->rsa, 8);
2398 #endif
2399 		break;
2400 	case KEY_DSA_CERT:
2401 		/* Skip nonce */
2402 		if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
2403 			ret = SSH_ERR_INVALID_FORMAT;
2404 			goto out;
2405 		}
2406 		/* FALLTHROUGH */
2407 	case KEY_DSA:
2408 		if ((key = sshkey_new(type)) == NULL) {
2409 			ret = SSH_ERR_ALLOC_FAIL;
2410 			goto out;
2411 		}
2412 		if (sshbuf_get_bignum2(b, &dsa_p) != 0 ||
2413 		    sshbuf_get_bignum2(b, &dsa_q) != 0 ||
2414 		    sshbuf_get_bignum2(b, &dsa_g) != 0 ||
2415 		    sshbuf_get_bignum2(b, &dsa_pub_key) != 0) {
2416 			ret = SSH_ERR_INVALID_FORMAT;
2417 			goto out;
2418 		}
2419 		if (!DSA_set0_pqg(key->dsa, dsa_p, dsa_q, dsa_g)) {
2420 			ret = SSH_ERR_LIBCRYPTO_ERROR;
2421 			goto out;
2422 		}
2423 		dsa_p = dsa_q = dsa_g = NULL; /* transferred */
2424 		if (!DSA_set0_key(key->dsa, dsa_pub_key, NULL)) {
2425 			ret = SSH_ERR_LIBCRYPTO_ERROR;
2426 			goto out;
2427 		}
2428 		dsa_pub_key = NULL; /* transferred */
2429 #ifdef DEBUG_PK
2430 		DSA_print_fp(stderr, key->dsa, 8);
2431 #endif
2432 		break;
2433 # ifdef OPENSSL_HAS_ECC
2434 	case KEY_ECDSA_CERT:
2435 	case KEY_ECDSA_SK_CERT:
2436 		/* Skip nonce */
2437 		if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
2438 			ret = SSH_ERR_INVALID_FORMAT;
2439 			goto out;
2440 		}
2441 		/* FALLTHROUGH */
2442 	case KEY_ECDSA:
2443 	case KEY_ECDSA_SK:
2444 		if ((key = sshkey_new(type)) == NULL) {
2445 			ret = SSH_ERR_ALLOC_FAIL;
2446 			goto out;
2447 		}
2448 		key->ecdsa_nid = sshkey_ecdsa_nid_from_name(ktype);
2449 		if (sshbuf_get_cstring(b, &curve, NULL) != 0) {
2450 			ret = SSH_ERR_INVALID_FORMAT;
2451 			goto out;
2452 		}
2453 		if (key->ecdsa_nid != sshkey_curve_name_to_nid(curve)) {
2454 			ret = SSH_ERR_EC_CURVE_MISMATCH;
2455 			goto out;
2456 		}
2457 		EC_KEY_free(key->ecdsa);
2458 		if ((key->ecdsa = EC_KEY_new_by_curve_name(key->ecdsa_nid))
2459 		    == NULL) {
2460 			ret = SSH_ERR_EC_CURVE_INVALID;
2461 			goto out;
2462 		}
2463 		if ((q = EC_POINT_new(EC_KEY_get0_group(key->ecdsa))) == NULL) {
2464 			ret = SSH_ERR_ALLOC_FAIL;
2465 			goto out;
2466 		}
2467 		if (sshbuf_get_ec(b, q, EC_KEY_get0_group(key->ecdsa)) != 0) {
2468 			ret = SSH_ERR_INVALID_FORMAT;
2469 			goto out;
2470 		}
2471 		if (sshkey_ec_validate_public(EC_KEY_get0_group(key->ecdsa),
2472 		    q) != 0) {
2473 			ret = SSH_ERR_KEY_INVALID_EC_VALUE;
2474 			goto out;
2475 		}
2476 		if (EC_KEY_set_public_key(key->ecdsa, q) != 1) {
2477 			/* XXX assume it is a allocation error */
2478 			ret = SSH_ERR_ALLOC_FAIL;
2479 			goto out;
2480 		}
2481 #ifdef DEBUG_PK
2482 		sshkey_dump_ec_point(EC_KEY_get0_group(key->ecdsa), q);
2483 #endif
2484 		if (type == KEY_ECDSA_SK || type == KEY_ECDSA_SK_CERT) {
2485 			/* Parse additional security-key application string */
2486 			if (sshbuf_get_cstring(b, &key->sk_application,
2487 			    NULL) != 0) {
2488 				ret = SSH_ERR_INVALID_FORMAT;
2489 				goto out;
2490 			}
2491 #ifdef DEBUG_PK
2492 			fprintf(stderr, "App: %s\n", key->sk_application);
2493 #endif
2494 		}
2495 		break;
2496 # endif /* OPENSSL_HAS_ECC */
2497 #endif /* WITH_OPENSSL */
2498 	case KEY_ED25519_CERT:
2499 	case KEY_ED25519_SK_CERT:
2500 		/* Skip nonce */
2501 		if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
2502 			ret = SSH_ERR_INVALID_FORMAT;
2503 			goto out;
2504 		}
2505 		/* FALLTHROUGH */
2506 	case KEY_ED25519:
2507 	case KEY_ED25519_SK:
2508 		if ((ret = sshbuf_get_string(b, &pk, &len)) != 0)
2509 			goto out;
2510 		if (len != ED25519_PK_SZ) {
2511 			ret = SSH_ERR_INVALID_FORMAT;
2512 			goto out;
2513 		}
2514 		if ((key = sshkey_new(type)) == NULL) {
2515 			ret = SSH_ERR_ALLOC_FAIL;
2516 			goto out;
2517 		}
2518 		if (type == KEY_ED25519_SK || type == KEY_ED25519_SK_CERT) {
2519 			/* Parse additional security-key application string */
2520 			if (sshbuf_get_cstring(b, &key->sk_application,
2521 			    NULL) != 0) {
2522 				ret = SSH_ERR_INVALID_FORMAT;
2523 				goto out;
2524 			}
2525 #ifdef DEBUG_PK
2526 			fprintf(stderr, "App: %s\n", key->sk_application);
2527 #endif
2528 		}
2529 		key->ed25519_pk = pk;
2530 		pk = NULL;
2531 		break;
2532 #ifdef WITH_XMSS
2533 	case KEY_XMSS_CERT:
2534 		/* Skip nonce */
2535 		if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
2536 			ret = SSH_ERR_INVALID_FORMAT;
2537 			goto out;
2538 		}
2539 		/* FALLTHROUGH */
2540 	case KEY_XMSS:
2541 		if ((ret = sshbuf_get_cstring(b, &xmss_name, NULL)) != 0)
2542 			goto out;
2543 		if ((key = sshkey_new(type)) == NULL) {
2544 			ret = SSH_ERR_ALLOC_FAIL;
2545 			goto out;
2546 		}
2547 		if ((ret = sshkey_xmss_init(key, xmss_name)) != 0)
2548 			goto out;
2549 		if ((ret = sshbuf_get_string(b, &pk, &len)) != 0)
2550 			goto out;
2551 		if (len == 0 || len != sshkey_xmss_pklen(key)) {
2552 			ret = SSH_ERR_INVALID_FORMAT;
2553 			goto out;
2554 		}
2555 		key->xmss_pk = pk;
2556 		pk = NULL;
2557 		if (type != KEY_XMSS_CERT &&
2558 		    (ret = sshkey_xmss_deserialize_pk_info(key, b)) != 0)
2559 			goto out;
2560 		break;
2561 #endif /* WITH_XMSS */
2562 	case KEY_UNSPEC:
2563 	default:
2564 		ret = SSH_ERR_KEY_TYPE_UNKNOWN;
2565 		goto out;
2566 	}
2567 
2568 	/* Parse certificate potion */
2569 	if (sshkey_is_cert(key) && (ret = cert_parse(b, key, copy)) != 0)
2570 		goto out;
2571 
2572 	if (key != NULL && sshbuf_len(b) != 0) {
2573 		ret = SSH_ERR_INVALID_FORMAT;
2574 		goto out;
2575 	}
2576 	ret = 0;
2577 	if (keyp != NULL) {
2578 		*keyp = key;
2579 		key = NULL;
2580 	}
2581  out:
2582 	sshbuf_free(copy);
2583 	sshkey_free(key);
2584 	free(xmss_name);
2585 	free(ktype);
2586 	free(curve);
2587 	free(pk);
2588 #if defined(WITH_OPENSSL)
2589 	BN_clear_free(rsa_n);
2590 	BN_clear_free(rsa_e);
2591 	BN_clear_free(dsa_p);
2592 	BN_clear_free(dsa_q);
2593 	BN_clear_free(dsa_g);
2594 	BN_clear_free(dsa_pub_key);
2595 # if defined(OPENSSL_HAS_ECC)
2596 	EC_POINT_free(q);
2597 # endif /* OPENSSL_HAS_ECC */
2598 #endif /* WITH_OPENSSL */
2599 	return ret;
2600 }
2601 
2602 int
2603 sshkey_from_blob(const u_char *blob, size_t blen, struct sshkey **keyp)
2604 {
2605 	struct sshbuf *b;
2606 	int r;
2607 
2608 	if ((b = sshbuf_from(blob, blen)) == NULL)
2609 		return SSH_ERR_ALLOC_FAIL;
2610 	r = sshkey_from_blob_internal(b, keyp, 1);
2611 	sshbuf_free(b);
2612 	return r;
2613 }
2614 
2615 int
2616 sshkey_fromb(struct sshbuf *b, struct sshkey **keyp)
2617 {
2618 	return sshkey_from_blob_internal(b, keyp, 1);
2619 }
2620 
2621 int
2622 sshkey_froms(struct sshbuf *buf, struct sshkey **keyp)
2623 {
2624 	struct sshbuf *b;
2625 	int r;
2626 
2627 	if ((r = sshbuf_froms(buf, &b)) != 0)
2628 		return r;
2629 	r = sshkey_from_blob_internal(b, keyp, 1);
2630 	sshbuf_free(b);
2631 	return r;
2632 }
2633 
2634 int
2635 sshkey_get_sigtype(const u_char *sig, size_t siglen, char **sigtypep)
2636 {
2637 	int r;
2638 	struct sshbuf *b = NULL;
2639 	char *sigtype = NULL;
2640 
2641 	if (sigtypep != NULL)
2642 		*sigtypep = NULL;
2643 	if ((b = sshbuf_from(sig, siglen)) == NULL)
2644 		return SSH_ERR_ALLOC_FAIL;
2645 	if ((r = sshbuf_get_cstring(b, &sigtype, NULL)) != 0)
2646 		goto out;
2647 	/* success */
2648 	if (sigtypep != NULL) {
2649 		*sigtypep = sigtype;
2650 		sigtype = NULL;
2651 	}
2652 	r = 0;
2653  out:
2654 	free(sigtype);
2655 	sshbuf_free(b);
2656 	return r;
2657 }
2658 
2659 /*
2660  *
2661  * Checks whether a certificate's signature type is allowed.
2662  * Returns 0 (success) if the certificate signature type appears in the
2663  * "allowed" pattern-list, or the key is not a certificate to begin with.
2664  * Otherwise returns a ssherr.h code.
2665  */
2666 int
2667 sshkey_check_cert_sigtype(const struct sshkey *key, const char *allowed)
2668 {
2669 	if (key == NULL || allowed == NULL)
2670 		return SSH_ERR_INVALID_ARGUMENT;
2671 	if (!sshkey_type_is_cert(key->type))
2672 		return 0;
2673 	if (key->cert == NULL || key->cert->signature_type == NULL)
2674 		return SSH_ERR_INVALID_ARGUMENT;
2675 	if (match_pattern_list(key->cert->signature_type, allowed, 0) != 1)
2676 		return SSH_ERR_SIGN_ALG_UNSUPPORTED;
2677 	return 0;
2678 }
2679 
2680 /*
2681  * Returns the expected signature algorithm for a given public key algorithm.
2682  */
2683 const char *
2684 sshkey_sigalg_by_name(const char *name)
2685 {
2686 	const struct keytype *kt;
2687 
2688 	for (kt = keytypes; kt->type != -1; kt++) {
2689 		if (strcmp(kt->name, name) != 0)
2690 			continue;
2691 		if (kt->sigalg != NULL)
2692 			return kt->sigalg;
2693 		if (!kt->cert)
2694 			return kt->name;
2695 		return sshkey_ssh_name_from_type_nid(
2696 		    sshkey_type_plain(kt->type), kt->nid);
2697 	}
2698 	return NULL;
2699 }
2700 
2701 /*
2702  * Verifies that the signature algorithm appearing inside the signature blob
2703  * matches that which was requested.
2704  */
2705 int
2706 sshkey_check_sigtype(const u_char *sig, size_t siglen,
2707     const char *requested_alg)
2708 {
2709 	const char *expected_alg;
2710 	char *sigtype = NULL;
2711 	int r;
2712 
2713 	if (requested_alg == NULL)
2714 		return 0;
2715 	if ((expected_alg = sshkey_sigalg_by_name(requested_alg)) == NULL)
2716 		return SSH_ERR_INVALID_ARGUMENT;
2717 	if ((r = sshkey_get_sigtype(sig, siglen, &sigtype)) != 0)
2718 		return r;
2719 	r = strcmp(expected_alg, sigtype) == 0;
2720 	free(sigtype);
2721 	return r ? 0 : SSH_ERR_SIGN_ALG_UNSUPPORTED;
2722 }
2723 
2724 int
2725 sshkey_sign(struct sshkey *key,
2726     u_char **sigp, size_t *lenp,
2727     const u_char *data, size_t datalen,
2728     const char *alg, const char *sk_provider, u_int compat)
2729 {
2730 	int was_shielded = sshkey_is_shielded(key);
2731 	int r2, r = SSH_ERR_INTERNAL_ERROR;
2732 
2733 	if (sigp != NULL)
2734 		*sigp = NULL;
2735 	if (lenp != NULL)
2736 		*lenp = 0;
2737 	if (datalen > SSH_KEY_MAX_SIGN_DATA_SIZE)
2738 		return SSH_ERR_INVALID_ARGUMENT;
2739 	if ((r = sshkey_unshield_private(key)) != 0)
2740 		return r;
2741 	switch (key->type) {
2742 #ifdef WITH_OPENSSL
2743 	case KEY_DSA_CERT:
2744 	case KEY_DSA:
2745 		r = ssh_dss_sign(key, sigp, lenp, data, datalen, compat);
2746 		break;
2747 # ifdef OPENSSL_HAS_ECC
2748 	case KEY_ECDSA_CERT:
2749 	case KEY_ECDSA:
2750 		r = ssh_ecdsa_sign(key, sigp, lenp, data, datalen, compat);
2751 		break;
2752 #  ifdef ENABLE_SK
2753 	case KEY_ECDSA_SK_CERT:
2754 	case KEY_ECDSA_SK:
2755 		r = sshsk_sign(sk_provider, key, sigp, lenp, data, datalen,
2756 		    compat);
2757 		break;
2758 #  endif /* ENABLE_SK */
2759 # endif /* OPENSSL_HAS_ECC */
2760 	case KEY_RSA_CERT:
2761 	case KEY_RSA:
2762 		r = ssh_rsa_sign(key, sigp, lenp, data, datalen, alg);
2763 		break;
2764 #endif /* WITH_OPENSSL */
2765 	case KEY_ED25519:
2766 	case KEY_ED25519_CERT:
2767 		r = ssh_ed25519_sign(key, sigp, lenp, data, datalen, compat);
2768 		break;
2769 #ifdef ENABLE_SK
2770 	case KEY_ED25519_SK:
2771 	case KEY_ED25519_SK_CERT:
2772 		r = sshsk_sign(sk_provider, key, sigp, lenp, data, datalen,
2773 		    compat);
2774 		break;
2775 #endif /* ENABLE_SK */
2776 #ifdef WITH_XMSS
2777 	case KEY_XMSS:
2778 	case KEY_XMSS_CERT:
2779 		r = ssh_xmss_sign(key, sigp, lenp, data, datalen, compat);
2780 		break;
2781 #endif /* WITH_XMSS */
2782 	default:
2783 		r = SSH_ERR_KEY_TYPE_UNKNOWN;
2784 		break;
2785 	}
2786 	if (was_shielded && (r2 = sshkey_shield_private(key)) != 0)
2787 		return r2;
2788 	return r;
2789 }
2790 
2791 /*
2792  * ssh_key_verify returns 0 for a correct signature  and < 0 on error.
2793  * If "alg" specified, then the signature must use that algorithm.
2794  */
2795 int
2796 sshkey_verify(const struct sshkey *key,
2797     const u_char *sig, size_t siglen,
2798     const u_char *data, size_t dlen, const char *alg, u_int compat)
2799 {
2800 	if (siglen == 0 || dlen > SSH_KEY_MAX_SIGN_DATA_SIZE)
2801 		return SSH_ERR_INVALID_ARGUMENT;
2802 	switch (key->type) {
2803 #ifdef WITH_OPENSSL
2804 	case KEY_DSA_CERT:
2805 	case KEY_DSA:
2806 		return ssh_dss_verify(key, sig, siglen, data, dlen, compat);
2807 # ifdef OPENSSL_HAS_ECC
2808 	case KEY_ECDSA_CERT:
2809 	case KEY_ECDSA:
2810 		return ssh_ecdsa_verify(key, sig, siglen, data, dlen, compat);
2811 #  ifdef ENABLE_SK
2812 	case KEY_ECDSA_SK_CERT:
2813 	case KEY_ECDSA_SK:
2814 		return ssh_ecdsa_sk_verify(key, sig, siglen, data, dlen,
2815 		    compat);
2816 #  endif /* ENABLE_SK */
2817 # endif /* OPENSSL_HAS_ECC */
2818 	case KEY_RSA_CERT:
2819 	case KEY_RSA:
2820 		return ssh_rsa_verify(key, sig, siglen, data, dlen, alg);
2821 #endif /* WITH_OPENSSL */
2822 	case KEY_ED25519:
2823 	case KEY_ED25519_CERT:
2824 		return ssh_ed25519_verify(key, sig, siglen, data, dlen, compat);
2825 	case KEY_ED25519_SK:
2826 	case KEY_ED25519_SK_CERT:
2827 		return ssh_ed25519_sk_verify(key, sig, siglen, data, dlen,
2828 		    compat);
2829 #ifdef WITH_XMSS
2830 	case KEY_XMSS:
2831 	case KEY_XMSS_CERT:
2832 		return ssh_xmss_verify(key, sig, siglen, data, dlen, compat);
2833 #endif /* WITH_XMSS */
2834 	default:
2835 		return SSH_ERR_KEY_TYPE_UNKNOWN;
2836 	}
2837 }
2838 
2839 /* Convert a plain key to their _CERT equivalent */
2840 int
2841 sshkey_to_certified(struct sshkey *k)
2842 {
2843 	int newtype;
2844 
2845 	switch (k->type) {
2846 #ifdef WITH_OPENSSL
2847 	case KEY_RSA:
2848 		newtype = KEY_RSA_CERT;
2849 		break;
2850 	case KEY_DSA:
2851 		newtype = KEY_DSA_CERT;
2852 		break;
2853 	case KEY_ECDSA:
2854 		newtype = KEY_ECDSA_CERT;
2855 		break;
2856 	case KEY_ECDSA_SK:
2857 		newtype = KEY_ECDSA_SK_CERT;
2858 		break;
2859 #endif /* WITH_OPENSSL */
2860 	case KEY_ED25519_SK:
2861 		newtype = KEY_ED25519_SK_CERT;
2862 		break;
2863 	case KEY_ED25519:
2864 		newtype = KEY_ED25519_CERT;
2865 		break;
2866 #ifdef WITH_XMSS
2867 	case KEY_XMSS:
2868 		newtype = KEY_XMSS_CERT;
2869 		break;
2870 #endif /* WITH_XMSS */
2871 	default:
2872 		return SSH_ERR_INVALID_ARGUMENT;
2873 	}
2874 	if ((k->cert = cert_new()) == NULL)
2875 		return SSH_ERR_ALLOC_FAIL;
2876 	k->type = newtype;
2877 	return 0;
2878 }
2879 
2880 /* Convert a certificate to its raw key equivalent */
2881 int
2882 sshkey_drop_cert(struct sshkey *k)
2883 {
2884 	if (!sshkey_type_is_cert(k->type))
2885 		return SSH_ERR_KEY_TYPE_UNKNOWN;
2886 	cert_free(k->cert);
2887 	k->cert = NULL;
2888 	k->type = sshkey_type_plain(k->type);
2889 	return 0;
2890 }
2891 
2892 /* Sign a certified key, (re-)generating the signed certblob. */
2893 int
2894 sshkey_certify_custom(struct sshkey *k, struct sshkey *ca, const char *alg,
2895     const char *sk_provider, sshkey_certify_signer *signer, void *signer_ctx)
2896 {
2897 	struct sshbuf *principals = NULL;
2898 	u_char *ca_blob = NULL, *sig_blob = NULL, nonce[32];
2899 	size_t i, ca_len, sig_len;
2900 	int ret = SSH_ERR_INTERNAL_ERROR;
2901 	struct sshbuf *cert = NULL;
2902 	char *sigtype = NULL;
2903 #ifdef WITH_OPENSSL
2904 	const BIGNUM *rsa_n, *rsa_e, *dsa_p, *dsa_q, *dsa_g, *dsa_pub_key;
2905 #endif /* WITH_OPENSSL */
2906 
2907 	if (k == NULL || k->cert == NULL ||
2908 	    k->cert->certblob == NULL || ca == NULL)
2909 		return SSH_ERR_INVALID_ARGUMENT;
2910 	if (!sshkey_is_cert(k))
2911 		return SSH_ERR_KEY_TYPE_UNKNOWN;
2912 	if (!sshkey_type_is_valid_ca(ca->type))
2913 		return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
2914 
2915 	/*
2916 	 * If no alg specified as argument but a signature_type was set,
2917 	 * then prefer that. If both were specified, then they must match.
2918 	 */
2919 	if (alg == NULL)
2920 		alg = k->cert->signature_type;
2921 	else if (k->cert->signature_type != NULL &&
2922 	    strcmp(alg, k->cert->signature_type) != 0)
2923 		return SSH_ERR_INVALID_ARGUMENT;
2924 
2925 	/*
2926 	 * If no signing algorithm or signature_type was specified and we're
2927 	 * using a RSA key, then default to a good signature algorithm.
2928 	 */
2929 	if (alg == NULL && ca->type == KEY_RSA)
2930 		alg = "rsa-sha2-512";
2931 
2932 	if ((ret = sshkey_to_blob(ca, &ca_blob, &ca_len)) != 0)
2933 		return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
2934 
2935 	cert = k->cert->certblob; /* for readability */
2936 	sshbuf_reset(cert);
2937 	if ((ret = sshbuf_put_cstring(cert, sshkey_ssh_name(k))) != 0)
2938 		goto out;
2939 
2940 	/* -v01 certs put nonce first */
2941 	arc4random_buf(&nonce, sizeof(nonce));
2942 	if ((ret = sshbuf_put_string(cert, nonce, sizeof(nonce))) != 0)
2943 		goto out;
2944 
2945 	/* XXX this substantially duplicates to_blob(); refactor */
2946 	switch (k->type) {
2947 #ifdef WITH_OPENSSL
2948 	case KEY_DSA_CERT:
2949 		DSA_get0_pqg(k->dsa, &dsa_p, &dsa_q, &dsa_g);
2950 		DSA_get0_key(k->dsa, &dsa_pub_key, NULL);
2951 		if ((ret = sshbuf_put_bignum2(cert, dsa_p)) != 0 ||
2952 		    (ret = sshbuf_put_bignum2(cert, dsa_q)) != 0 ||
2953 		    (ret = sshbuf_put_bignum2(cert, dsa_g)) != 0 ||
2954 		    (ret = sshbuf_put_bignum2(cert, dsa_pub_key)) != 0)
2955 			goto out;
2956 		break;
2957 # ifdef OPENSSL_HAS_ECC
2958 	case KEY_ECDSA_CERT:
2959 	case KEY_ECDSA_SK_CERT:
2960 		if ((ret = sshbuf_put_cstring(cert,
2961 		    sshkey_curve_nid_to_name(k->ecdsa_nid))) != 0 ||
2962 		    (ret = sshbuf_put_ec(cert,
2963 		    EC_KEY_get0_public_key(k->ecdsa),
2964 		    EC_KEY_get0_group(k->ecdsa))) != 0)
2965 			goto out;
2966 		if (k->type == KEY_ECDSA_SK_CERT) {
2967 			if ((ret = sshbuf_put_cstring(cert,
2968 			    k->sk_application)) != 0)
2969 				goto out;
2970 		}
2971 		break;
2972 # endif /* OPENSSL_HAS_ECC */
2973 	case KEY_RSA_CERT:
2974 		RSA_get0_key(k->rsa, &rsa_n, &rsa_e, NULL);
2975 		if ((ret = sshbuf_put_bignum2(cert, rsa_e)) != 0 ||
2976 		    (ret = sshbuf_put_bignum2(cert, rsa_n)) != 0)
2977 			goto out;
2978 		break;
2979 #endif /* WITH_OPENSSL */
2980 	case KEY_ED25519_CERT:
2981 		if ((ret = sshbuf_put_string(cert,
2982 		    k->ed25519_pk, ED25519_PK_SZ)) != 0)
2983 			goto out;
2984 		break;
2985 #ifdef WITH_XMSS
2986 	case KEY_XMSS_CERT:
2987 		if (k->xmss_name == NULL) {
2988 			ret = SSH_ERR_INVALID_ARGUMENT;
2989 			goto out;
2990 		}
2991 		if ((ret = sshbuf_put_cstring(cert, k->xmss_name)) ||
2992 		    (ret = sshbuf_put_string(cert,
2993 		    k->xmss_pk, sshkey_xmss_pklen(k))) != 0)
2994 			goto out;
2995 		break;
2996 #endif /* WITH_XMSS */
2997 	default:
2998 		ret = SSH_ERR_INVALID_ARGUMENT;
2999 		goto out;
3000 	}
3001 
3002 	if ((ret = sshbuf_put_u64(cert, k->cert->serial)) != 0 ||
3003 	    (ret = sshbuf_put_u32(cert, k->cert->type)) != 0 ||
3004 	    (ret = sshbuf_put_cstring(cert, k->cert->key_id)) != 0)
3005 		goto out;
3006 
3007 	if ((principals = sshbuf_new()) == NULL) {
3008 		ret = SSH_ERR_ALLOC_FAIL;
3009 		goto out;
3010 	}
3011 	for (i = 0; i < k->cert->nprincipals; i++) {
3012 		if ((ret = sshbuf_put_cstring(principals,
3013 		    k->cert->principals[i])) != 0)
3014 			goto out;
3015 	}
3016 	if ((ret = sshbuf_put_stringb(cert, principals)) != 0 ||
3017 	    (ret = sshbuf_put_u64(cert, k->cert->valid_after)) != 0 ||
3018 	    (ret = sshbuf_put_u64(cert, k->cert->valid_before)) != 0 ||
3019 	    (ret = sshbuf_put_stringb(cert, k->cert->critical)) != 0 ||
3020 	    (ret = sshbuf_put_stringb(cert, k->cert->extensions)) != 0 ||
3021 	    (ret = sshbuf_put_string(cert, NULL, 0)) != 0 || /* Reserved */
3022 	    (ret = sshbuf_put_string(cert, ca_blob, ca_len)) != 0)
3023 		goto out;
3024 
3025 	/* Sign the whole mess */
3026 	if ((ret = signer(ca, &sig_blob, &sig_len, sshbuf_ptr(cert),
3027 	    sshbuf_len(cert), alg, sk_provider, 0, signer_ctx)) != 0)
3028 		goto out;
3029 	/* Check and update signature_type against what was actually used */
3030 	if ((ret = sshkey_get_sigtype(sig_blob, sig_len, &sigtype)) != 0)
3031 		goto out;
3032 	if (alg != NULL && strcmp(alg, sigtype) != 0) {
3033 		ret = SSH_ERR_SIGN_ALG_UNSUPPORTED;