xref: /openssh-portable/sshkey.c (revision 4a05d789)
1 /* $OpenBSD: sshkey.c,v 1.99 2020/01/21 05:56:56 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 	case KEY_ED25519_SK_CERT:
827 #ifdef WITH_XMSS
828 	case KEY_XMSS_CERT:
829 #endif /* WITH_XMSS */
830 		/* Use the existing blob */
831 		/* XXX modified flag? */
832 		if ((ret = sshbuf_putb(b, key->cert->certblob)) != 0)
833 			return ret;
834 		break;
835 #ifdef WITH_OPENSSL
836 	case KEY_DSA:
837 		if (key->dsa == NULL)
838 			return SSH_ERR_INVALID_ARGUMENT;
839 		DSA_get0_pqg(key->dsa, &dsa_p, &dsa_q, &dsa_g);
840 		DSA_get0_key(key->dsa, &dsa_pub_key, NULL);
841 		if ((ret = sshbuf_put_cstring(b, typename)) != 0 ||
842 		    (ret = sshbuf_put_bignum2(b, dsa_p)) != 0 ||
843 		    (ret = sshbuf_put_bignum2(b, dsa_q)) != 0 ||
844 		    (ret = sshbuf_put_bignum2(b, dsa_g)) != 0 ||
845 		    (ret = sshbuf_put_bignum2(b, dsa_pub_key)) != 0)
846 			return ret;
847 		break;
848 # ifdef OPENSSL_HAS_ECC
849 	case KEY_ECDSA:
850 	case KEY_ECDSA_SK:
851 		if (key->ecdsa == NULL)
852 			return SSH_ERR_INVALID_ARGUMENT;
853 		if ((ret = sshbuf_put_cstring(b, typename)) != 0 ||
854 		    (ret = sshbuf_put_cstring(b,
855 		    sshkey_curve_nid_to_name(key->ecdsa_nid))) != 0 ||
856 		    (ret = sshbuf_put_eckey(b, key->ecdsa)) != 0)
857 			return ret;
858 		if (type == KEY_ECDSA_SK) {
859 			if ((ret = sshbuf_put_cstring(b,
860 			    key->sk_application)) != 0)
861 				return ret;
862 		}
863 		break;
864 # endif
865 	case KEY_RSA:
866 		if (key->rsa == NULL)
867 			return SSH_ERR_INVALID_ARGUMENT;
868 		RSA_get0_key(key->rsa, &rsa_n, &rsa_e, NULL);
869 		if ((ret = sshbuf_put_cstring(b, typename)) != 0 ||
870 		    (ret = sshbuf_put_bignum2(b, rsa_e)) != 0 ||
871 		    (ret = sshbuf_put_bignum2(b, rsa_n)) != 0)
872 			return ret;
873 		break;
874 #endif /* WITH_OPENSSL */
875 	case KEY_ED25519:
876 	case KEY_ED25519_SK:
877 		if (key->ed25519_pk == NULL)
878 			return SSH_ERR_INVALID_ARGUMENT;
879 		if ((ret = sshbuf_put_cstring(b, typename)) != 0 ||
880 		    (ret = sshbuf_put_string(b,
881 		    key->ed25519_pk, ED25519_PK_SZ)) != 0)
882 			return ret;
883 		if (type == KEY_ED25519_SK) {
884 			if ((ret = sshbuf_put_cstring(b,
885 			    key->sk_application)) != 0)
886 				return ret;
887 		}
888 		break;
889 #ifdef WITH_XMSS
890 	case KEY_XMSS:
891 		if (key->xmss_name == NULL || key->xmss_pk == NULL ||
892 		    sshkey_xmss_pklen(key) == 0)
893 			return SSH_ERR_INVALID_ARGUMENT;
894 		if ((ret = sshbuf_put_cstring(b, typename)) != 0 ||
895 		    (ret = sshbuf_put_cstring(b, key->xmss_name)) != 0 ||
896 		    (ret = sshbuf_put_string(b,
897 		    key->xmss_pk, sshkey_xmss_pklen(key))) != 0 ||
898 		    (ret = sshkey_xmss_serialize_pk_info(key, b, opts)) != 0)
899 			return ret;
900 		break;
901 #endif /* WITH_XMSS */
902 	default:
903 		return SSH_ERR_KEY_TYPE_UNKNOWN;
904 	}
905 	return 0;
906 }
907 
908 int
909 sshkey_putb(const struct sshkey *key, struct sshbuf *b)
910 {
911 	return to_blob_buf(key, b, 0, SSHKEY_SERIALIZE_DEFAULT);
912 }
913 
914 int
915 sshkey_puts_opts(const struct sshkey *key, struct sshbuf *b,
916     enum sshkey_serialize_rep opts)
917 {
918 	struct sshbuf *tmp;
919 	int r;
920 
921 	if ((tmp = sshbuf_new()) == NULL)
922 		return SSH_ERR_ALLOC_FAIL;
923 	r = to_blob_buf(key, tmp, 0, opts);
924 	if (r == 0)
925 		r = sshbuf_put_stringb(b, tmp);
926 	sshbuf_free(tmp);
927 	return r;
928 }
929 
930 int
931 sshkey_puts(const struct sshkey *key, struct sshbuf *b)
932 {
933 	return sshkey_puts_opts(key, b, SSHKEY_SERIALIZE_DEFAULT);
934 }
935 
936 int
937 sshkey_putb_plain(const struct sshkey *key, struct sshbuf *b)
938 {
939 	return to_blob_buf(key, b, 1, SSHKEY_SERIALIZE_DEFAULT);
940 }
941 
942 static int
943 to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp, int force_plain,
944     enum sshkey_serialize_rep opts)
945 {
946 	int ret = SSH_ERR_INTERNAL_ERROR;
947 	size_t len;
948 	struct sshbuf *b = NULL;
949 
950 	if (lenp != NULL)
951 		*lenp = 0;
952 	if (blobp != NULL)
953 		*blobp = NULL;
954 	if ((b = sshbuf_new()) == NULL)
955 		return SSH_ERR_ALLOC_FAIL;
956 	if ((ret = to_blob_buf(key, b, force_plain, opts)) != 0)
957 		goto out;
958 	len = sshbuf_len(b);
959 	if (lenp != NULL)
960 		*lenp = len;
961 	if (blobp != NULL) {
962 		if ((*blobp = malloc(len)) == NULL) {
963 			ret = SSH_ERR_ALLOC_FAIL;
964 			goto out;
965 		}
966 		memcpy(*blobp, sshbuf_ptr(b), len);
967 	}
968 	ret = 0;
969  out:
970 	sshbuf_free(b);
971 	return ret;
972 }
973 
974 int
975 sshkey_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp)
976 {
977 	return to_blob(key, blobp, lenp, 0, SSHKEY_SERIALIZE_DEFAULT);
978 }
979 
980 int
981 sshkey_plain_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp)
982 {
983 	return to_blob(key, blobp, lenp, 1, SSHKEY_SERIALIZE_DEFAULT);
984 }
985 
986 int
987 sshkey_fingerprint_raw(const struct sshkey *k, int dgst_alg,
988     u_char **retp, size_t *lenp)
989 {
990 	u_char *blob = NULL, *ret = NULL;
991 	size_t blob_len = 0;
992 	int r = SSH_ERR_INTERNAL_ERROR;
993 
994 	if (retp != NULL)
995 		*retp = NULL;
996 	if (lenp != NULL)
997 		*lenp = 0;
998 	if (ssh_digest_bytes(dgst_alg) == 0) {
999 		r = SSH_ERR_INVALID_ARGUMENT;
1000 		goto out;
1001 	}
1002 	if ((r = to_blob(k, &blob, &blob_len, 1, SSHKEY_SERIALIZE_DEFAULT))
1003 	    != 0)
1004 		goto out;
1005 	if ((ret = calloc(1, SSH_DIGEST_MAX_LENGTH)) == NULL) {
1006 		r = SSH_ERR_ALLOC_FAIL;
1007 		goto out;
1008 	}
1009 	if ((r = ssh_digest_memory(dgst_alg, blob, blob_len,
1010 	    ret, SSH_DIGEST_MAX_LENGTH)) != 0)
1011 		goto out;
1012 	/* success */
1013 	if (retp != NULL) {
1014 		*retp = ret;
1015 		ret = NULL;
1016 	}
1017 	if (lenp != NULL)
1018 		*lenp = ssh_digest_bytes(dgst_alg);
1019 	r = 0;
1020  out:
1021 	free(ret);
1022 	if (blob != NULL) {
1023 		explicit_bzero(blob, blob_len);
1024 		free(blob);
1025 	}
1026 	return r;
1027 }
1028 
1029 static char *
1030 fingerprint_b64(const char *alg, u_char *dgst_raw, size_t dgst_raw_len)
1031 {
1032 	char *ret;
1033 	size_t plen = strlen(alg) + 1;
1034 	size_t rlen = ((dgst_raw_len + 2) / 3) * 4 + plen + 1;
1035 
1036 	if (dgst_raw_len > 65536 || (ret = calloc(1, rlen)) == NULL)
1037 		return NULL;
1038 	strlcpy(ret, alg, rlen);
1039 	strlcat(ret, ":", rlen);
1040 	if (dgst_raw_len == 0)
1041 		return ret;
1042 	if (b64_ntop(dgst_raw, dgst_raw_len, ret + plen, rlen - plen) == -1) {
1043 		freezero(ret, rlen);
1044 		return NULL;
1045 	}
1046 	/* Trim padding characters from end */
1047 	ret[strcspn(ret, "=")] = '\0';
1048 	return ret;
1049 }
1050 
1051 static char *
1052 fingerprint_hex(const char *alg, u_char *dgst_raw, size_t dgst_raw_len)
1053 {
1054 	char *retval, hex[5];
1055 	size_t i, rlen = dgst_raw_len * 3 + strlen(alg) + 2;
1056 
1057 	if (dgst_raw_len > 65536 || (retval = calloc(1, rlen)) == NULL)
1058 		return NULL;
1059 	strlcpy(retval, alg, rlen);
1060 	strlcat(retval, ":", rlen);
1061 	for (i = 0; i < dgst_raw_len; i++) {
1062 		snprintf(hex, sizeof(hex), "%s%02x",
1063 		    i > 0 ? ":" : "", dgst_raw[i]);
1064 		strlcat(retval, hex, rlen);
1065 	}
1066 	return retval;
1067 }
1068 
1069 static char *
1070 fingerprint_bubblebabble(u_char *dgst_raw, size_t dgst_raw_len)
1071 {
1072 	char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' };
1073 	char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm',
1074 	    'n', 'p', 'r', 's', 't', 'v', 'z', 'x' };
1075 	u_int i, j = 0, rounds, seed = 1;
1076 	char *retval;
1077 
1078 	rounds = (dgst_raw_len / 2) + 1;
1079 	if ((retval = calloc(rounds, 6)) == NULL)
1080 		return NULL;
1081 	retval[j++] = 'x';
1082 	for (i = 0; i < rounds; i++) {
1083 		u_int idx0, idx1, idx2, idx3, idx4;
1084 		if ((i + 1 < rounds) || (dgst_raw_len % 2 != 0)) {
1085 			idx0 = (((((u_int)(dgst_raw[2 * i])) >> 6) & 3) +
1086 			    seed) % 6;
1087 			idx1 = (((u_int)(dgst_raw[2 * i])) >> 2) & 15;
1088 			idx2 = ((((u_int)(dgst_raw[2 * i])) & 3) +
1089 			    (seed / 6)) % 6;
1090 			retval[j++] = vowels[idx0];
1091 			retval[j++] = consonants[idx1];
1092 			retval[j++] = vowels[idx2];
1093 			if ((i + 1) < rounds) {
1094 				idx3 = (((u_int)(dgst_raw[(2 * i) + 1])) >> 4) & 15;
1095 				idx4 = (((u_int)(dgst_raw[(2 * i) + 1]))) & 15;
1096 				retval[j++] = consonants[idx3];
1097 				retval[j++] = '-';
1098 				retval[j++] = consonants[idx4];
1099 				seed = ((seed * 5) +
1100 				    ((((u_int)(dgst_raw[2 * i])) * 7) +
1101 				    ((u_int)(dgst_raw[(2 * i) + 1])))) % 36;
1102 			}
1103 		} else {
1104 			idx0 = seed % 6;
1105 			idx1 = 16;
1106 			idx2 = seed / 6;
1107 			retval[j++] = vowels[idx0];
1108 			retval[j++] = consonants[idx1];
1109 			retval[j++] = vowels[idx2];
1110 		}
1111 	}
1112 	retval[j++] = 'x';
1113 	retval[j++] = '\0';
1114 	return retval;
1115 }
1116 
1117 /*
1118  * Draw an ASCII-Art representing the fingerprint so human brain can
1119  * profit from its built-in pattern recognition ability.
1120  * This technique is called "random art" and can be found in some
1121  * scientific publications like this original paper:
1122  *
1123  * "Hash Visualization: a New Technique to improve Real-World Security",
1124  * Perrig A. and Song D., 1999, International Workshop on Cryptographic
1125  * Techniques and E-Commerce (CrypTEC '99)
1126  * sparrow.ece.cmu.edu/~adrian/projects/validation/validation.pdf
1127  *
1128  * The subject came up in a talk by Dan Kaminsky, too.
1129  *
1130  * If you see the picture is different, the key is different.
1131  * If the picture looks the same, you still know nothing.
1132  *
1133  * The algorithm used here is a worm crawling over a discrete plane,
1134  * leaving a trace (augmenting the field) everywhere it goes.
1135  * Movement is taken from dgst_raw 2bit-wise.  Bumping into walls
1136  * makes the respective movement vector be ignored for this turn.
1137  * Graphs are not unambiguous, because circles in graphs can be
1138  * walked in either direction.
1139  */
1140 
1141 /*
1142  * Field sizes for the random art.  Have to be odd, so the starting point
1143  * can be in the exact middle of the picture, and FLDBASE should be >=8 .
1144  * Else pictures would be too dense, and drawing the frame would
1145  * fail, too, because the key type would not fit in anymore.
1146  */
1147 #define	FLDBASE		8
1148 #define	FLDSIZE_Y	(FLDBASE + 1)
1149 #define	FLDSIZE_X	(FLDBASE * 2 + 1)
1150 static char *
1151 fingerprint_randomart(const char *alg, u_char *dgst_raw, size_t dgst_raw_len,
1152     const struct sshkey *k)
1153 {
1154 	/*
1155 	 * Chars to be used after each other every time the worm
1156 	 * intersects with itself.  Matter of taste.
1157 	 */
1158 	char	*augmentation_string = " .o+=*BOX@%&#/^SE";
1159 	char	*retval, *p, title[FLDSIZE_X], hash[FLDSIZE_X];
1160 	u_char	 field[FLDSIZE_X][FLDSIZE_Y];
1161 	size_t	 i, tlen, hlen;
1162 	u_int	 b;
1163 	int	 x, y, r;
1164 	size_t	 len = strlen(augmentation_string) - 1;
1165 
1166 	if ((retval = calloc((FLDSIZE_X + 3), (FLDSIZE_Y + 2))) == NULL)
1167 		return NULL;
1168 
1169 	/* initialize field */
1170 	memset(field, 0, FLDSIZE_X * FLDSIZE_Y * sizeof(char));
1171 	x = FLDSIZE_X / 2;
1172 	y = FLDSIZE_Y / 2;
1173 
1174 	/* process raw key */
1175 	for (i = 0; i < dgst_raw_len; i++) {
1176 		int input;
1177 		/* each byte conveys four 2-bit move commands */
1178 		input = dgst_raw[i];
1179 		for (b = 0; b < 4; b++) {
1180 			/* evaluate 2 bit, rest is shifted later */
1181 			x += (input & 0x1) ? 1 : -1;
1182 			y += (input & 0x2) ? 1 : -1;
1183 
1184 			/* assure we are still in bounds */
1185 			x = MAXIMUM(x, 0);
1186 			y = MAXIMUM(y, 0);
1187 			x = MINIMUM(x, FLDSIZE_X - 1);
1188 			y = MINIMUM(y, FLDSIZE_Y - 1);
1189 
1190 			/* augment the field */
1191 			if (field[x][y] < len - 2)
1192 				field[x][y]++;
1193 			input = input >> 2;
1194 		}
1195 	}
1196 
1197 	/* mark starting point and end point*/
1198 	field[FLDSIZE_X / 2][FLDSIZE_Y / 2] = len - 1;
1199 	field[x][y] = len;
1200 
1201 	/* assemble title */
1202 	r = snprintf(title, sizeof(title), "[%s %u]",
1203 		sshkey_type(k), sshkey_size(k));
1204 	/* If [type size] won't fit, then try [type]; fits "[ED25519-CERT]" */
1205 	if (r < 0 || r > (int)sizeof(title))
1206 		r = snprintf(title, sizeof(title), "[%s]", sshkey_type(k));
1207 	tlen = (r <= 0) ? 0 : strlen(title);
1208 
1209 	/* assemble hash ID. */
1210 	r = snprintf(hash, sizeof(hash), "[%s]", alg);
1211 	hlen = (r <= 0) ? 0 : strlen(hash);
1212 
1213 	/* output upper border */
1214 	p = retval;
1215 	*p++ = '+';
1216 	for (i = 0; i < (FLDSIZE_X - tlen) / 2; i++)
1217 		*p++ = '-';
1218 	memcpy(p, title, tlen);
1219 	p += tlen;
1220 	for (i += tlen; i < FLDSIZE_X; i++)
1221 		*p++ = '-';
1222 	*p++ = '+';
1223 	*p++ = '\n';
1224 
1225 	/* output content */
1226 	for (y = 0; y < FLDSIZE_Y; y++) {
1227 		*p++ = '|';
1228 		for (x = 0; x < FLDSIZE_X; x++)
1229 			*p++ = augmentation_string[MINIMUM(field[x][y], len)];
1230 		*p++ = '|';
1231 		*p++ = '\n';
1232 	}
1233 
1234 	/* output lower border */
1235 	*p++ = '+';
1236 	for (i = 0; i < (FLDSIZE_X - hlen) / 2; i++)
1237 		*p++ = '-';
1238 	memcpy(p, hash, hlen);
1239 	p += hlen;
1240 	for (i += hlen; i < FLDSIZE_X; i++)
1241 		*p++ = '-';
1242 	*p++ = '+';
1243 
1244 	return retval;
1245 }
1246 
1247 char *
1248 sshkey_fingerprint(const struct sshkey *k, int dgst_alg,
1249     enum sshkey_fp_rep dgst_rep)
1250 {
1251 	char *retval = NULL;
1252 	u_char *dgst_raw;
1253 	size_t dgst_raw_len;
1254 
1255 	if (sshkey_fingerprint_raw(k, dgst_alg, &dgst_raw, &dgst_raw_len) != 0)
1256 		return NULL;
1257 	switch (dgst_rep) {
1258 	case SSH_FP_DEFAULT:
1259 		if (dgst_alg == SSH_DIGEST_MD5) {
1260 			retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg),
1261 			    dgst_raw, dgst_raw_len);
1262 		} else {
1263 			retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg),
1264 			    dgst_raw, dgst_raw_len);
1265 		}
1266 		break;
1267 	case SSH_FP_HEX:
1268 		retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg),
1269 		    dgst_raw, dgst_raw_len);
1270 		break;
1271 	case SSH_FP_BASE64:
1272 		retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg),
1273 		    dgst_raw, dgst_raw_len);
1274 		break;
1275 	case SSH_FP_BUBBLEBABBLE:
1276 		retval = fingerprint_bubblebabble(dgst_raw, dgst_raw_len);
1277 		break;
1278 	case SSH_FP_RANDOMART:
1279 		retval = fingerprint_randomart(ssh_digest_alg_name(dgst_alg),
1280 		    dgst_raw, dgst_raw_len, k);
1281 		break;
1282 	default:
1283 		explicit_bzero(dgst_raw, dgst_raw_len);
1284 		free(dgst_raw);
1285 		return NULL;
1286 	}
1287 	explicit_bzero(dgst_raw, dgst_raw_len);
1288 	free(dgst_raw);
1289 	return retval;
1290 }
1291 
1292 static int
1293 peek_type_nid(const char *s, size_t l, int *nid)
1294 {
1295 	const struct keytype *kt;
1296 
1297 	for (kt = keytypes; kt->type != -1; kt++) {
1298 		if (kt->name == NULL || strlen(kt->name) != l)
1299 			continue;
1300 		if (memcmp(s, kt->name, l) == 0) {
1301 			*nid = -1;
1302 			if (key_type_is_ecdsa_variant(kt->type))
1303 				*nid = kt->nid;
1304 			return kt->type;
1305 		}
1306 	}
1307 	return KEY_UNSPEC;
1308 }
1309 
1310 /* XXX this can now be made const char * */
1311 int
1312 sshkey_read(struct sshkey *ret, char **cpp)
1313 {
1314 	struct sshkey *k;
1315 	char *cp, *blobcopy;
1316 	size_t space;
1317 	int r, type, curve_nid = -1;
1318 	struct sshbuf *blob;
1319 
1320 	if (ret == NULL)
1321 		return SSH_ERR_INVALID_ARGUMENT;
1322 
1323 	switch (ret->type) {
1324 	case KEY_UNSPEC:
1325 	case KEY_RSA:
1326 	case KEY_DSA:
1327 	case KEY_ECDSA:
1328 	case KEY_ECDSA_SK:
1329 	case KEY_ED25519:
1330 	case KEY_ED25519_SK:
1331 	case KEY_DSA_CERT:
1332 	case KEY_ECDSA_CERT:
1333 	case KEY_ECDSA_SK_CERT:
1334 	case KEY_RSA_CERT:
1335 	case KEY_ED25519_CERT:
1336 	case KEY_ED25519_SK_CERT:
1337 #ifdef WITH_XMSS
1338 	case KEY_XMSS:
1339 	case KEY_XMSS_CERT:
1340 #endif /* WITH_XMSS */
1341 		break; /* ok */
1342 	default:
1343 		return SSH_ERR_INVALID_ARGUMENT;
1344 	}
1345 
1346 	/* Decode type */
1347 	cp = *cpp;
1348 	space = strcspn(cp, " \t");
1349 	if (space == strlen(cp))
1350 		return SSH_ERR_INVALID_FORMAT;
1351 	if ((type = peek_type_nid(cp, space, &curve_nid)) == KEY_UNSPEC)
1352 		return SSH_ERR_INVALID_FORMAT;
1353 
1354 	/* skip whitespace */
1355 	for (cp += space; *cp == ' ' || *cp == '\t'; cp++)
1356 		;
1357 	if (*cp == '\0')
1358 		return SSH_ERR_INVALID_FORMAT;
1359 	if (ret->type != KEY_UNSPEC && ret->type != type)
1360 		return SSH_ERR_KEY_TYPE_MISMATCH;
1361 	if ((blob = sshbuf_new()) == NULL)
1362 		return SSH_ERR_ALLOC_FAIL;
1363 
1364 	/* find end of keyblob and decode */
1365 	space = strcspn(cp, " \t");
1366 	if ((blobcopy = strndup(cp, space)) == NULL) {
1367 		sshbuf_free(blob);
1368 		return SSH_ERR_ALLOC_FAIL;
1369 	}
1370 	if ((r = sshbuf_b64tod(blob, blobcopy)) != 0) {
1371 		free(blobcopy);
1372 		sshbuf_free(blob);
1373 		return r;
1374 	}
1375 	free(blobcopy);
1376 	if ((r = sshkey_fromb(blob, &k)) != 0) {
1377 		sshbuf_free(blob);
1378 		return r;
1379 	}
1380 	sshbuf_free(blob);
1381 
1382 	/* skip whitespace and leave cp at start of comment */
1383 	for (cp += space; *cp == ' ' || *cp == '\t'; cp++)
1384 		;
1385 
1386 	/* ensure type of blob matches type at start of line */
1387 	if (k->type != type) {
1388 		sshkey_free(k);
1389 		return SSH_ERR_KEY_TYPE_MISMATCH;
1390 	}
1391 	if (key_type_is_ecdsa_variant(type) && curve_nid != k->ecdsa_nid) {
1392 		sshkey_free(k);
1393 		return SSH_ERR_EC_CURVE_MISMATCH;
1394 	}
1395 
1396 	/* Fill in ret from parsed key */
1397 	ret->type = type;
1398 	if (sshkey_is_cert(ret)) {
1399 		if (!sshkey_is_cert(k)) {
1400 			sshkey_free(k);
1401 			return SSH_ERR_EXPECTED_CERT;
1402 		}
1403 		if (ret->cert != NULL)
1404 			cert_free(ret->cert);
1405 		ret->cert = k->cert;
1406 		k->cert = NULL;
1407 	}
1408 	switch (sshkey_type_plain(ret->type)) {
1409 #ifdef WITH_OPENSSL
1410 	case KEY_RSA:
1411 		RSA_free(ret->rsa);
1412 		ret->rsa = k->rsa;
1413 		k->rsa = NULL;
1414 #ifdef DEBUG_PK
1415 		RSA_print_fp(stderr, ret->rsa, 8);
1416 #endif
1417 		break;
1418 	case KEY_DSA:
1419 		DSA_free(ret->dsa);
1420 		ret->dsa = k->dsa;
1421 		k->dsa = NULL;
1422 #ifdef DEBUG_PK
1423 		DSA_print_fp(stderr, ret->dsa, 8);
1424 #endif
1425 		break;
1426 # ifdef OPENSSL_HAS_ECC
1427 	case KEY_ECDSA:
1428 		EC_KEY_free(ret->ecdsa);
1429 		ret->ecdsa = k->ecdsa;
1430 		ret->ecdsa_nid = k->ecdsa_nid;
1431 		k->ecdsa = NULL;
1432 		k->ecdsa_nid = -1;
1433 #ifdef DEBUG_PK
1434 		sshkey_dump_ec_key(ret->ecdsa);
1435 #endif
1436 		break;
1437 	case KEY_ECDSA_SK:
1438 		EC_KEY_free(ret->ecdsa);
1439 		ret->ecdsa = k->ecdsa;
1440 		ret->ecdsa_nid = k->ecdsa_nid;
1441 		ret->sk_application = k->sk_application;
1442 		k->ecdsa = NULL;
1443 		k->ecdsa_nid = -1;
1444 		k->sk_application = NULL;
1445 #ifdef DEBUG_PK
1446 		sshkey_dump_ec_key(ret->ecdsa);
1447 		fprintf(stderr, "App: %s\n", ret->sk_application);
1448 #endif
1449 		break;
1450 # endif /* OPENSSL_HAS_ECC */
1451 #endif /* WITH_OPENSSL */
1452 	case KEY_ED25519:
1453 		freezero(ret->ed25519_pk, ED25519_PK_SZ);
1454 		ret->ed25519_pk = k->ed25519_pk;
1455 		k->ed25519_pk = NULL;
1456 #ifdef DEBUG_PK
1457 		/* XXX */
1458 #endif
1459 		break;
1460 	case KEY_ED25519_SK:
1461 		freezero(ret->ed25519_pk, ED25519_PK_SZ);
1462 		ret->ed25519_pk = k->ed25519_pk;
1463 		ret->sk_application = k->sk_application;
1464 		k->ed25519_pk = NULL;
1465 		k->sk_application = NULL;
1466 		break;
1467 #ifdef WITH_XMSS
1468 	case KEY_XMSS:
1469 		free(ret->xmss_pk);
1470 		ret->xmss_pk = k->xmss_pk;
1471 		k->xmss_pk = NULL;
1472 		free(ret->xmss_state);
1473 		ret->xmss_state = k->xmss_state;
1474 		k->xmss_state = NULL;
1475 		free(ret->xmss_name);
1476 		ret->xmss_name = k->xmss_name;
1477 		k->xmss_name = NULL;
1478 		free(ret->xmss_filename);
1479 		ret->xmss_filename = k->xmss_filename;
1480 		k->xmss_filename = NULL;
1481 #ifdef DEBUG_PK
1482 		/* XXX */
1483 #endif
1484 		break;
1485 #endif /* WITH_XMSS */
1486 	default:
1487 		sshkey_free(k);
1488 		return SSH_ERR_INTERNAL_ERROR;
1489 	}
1490 	sshkey_free(k);
1491 
1492 	/* success */
1493 	*cpp = cp;
1494 	return 0;
1495 }
1496 
1497 
1498 int
1499 sshkey_to_base64(const struct sshkey *key, char **b64p)
1500 {
1501 	int r = SSH_ERR_INTERNAL_ERROR;
1502 	struct sshbuf *b = NULL;
1503 	char *uu = NULL;
1504 
1505 	if (b64p != NULL)
1506 		*b64p = NULL;
1507 	if ((b = sshbuf_new()) == NULL)
1508 		return SSH_ERR_ALLOC_FAIL;
1509 	if ((r = sshkey_putb(key, b)) != 0)
1510 		goto out;
1511 	if ((uu = sshbuf_dtob64_string(b, 0)) == NULL) {
1512 		r = SSH_ERR_ALLOC_FAIL;
1513 		goto out;
1514 	}
1515 	/* Success */
1516 	if (b64p != NULL) {
1517 		*b64p = uu;
1518 		uu = NULL;
1519 	}
1520 	r = 0;
1521  out:
1522 	sshbuf_free(b);
1523 	free(uu);
1524 	return r;
1525 }
1526 
1527 int
1528 sshkey_format_text(const struct sshkey *key, struct sshbuf *b)
1529 {
1530 	int r = SSH_ERR_INTERNAL_ERROR;
1531 	char *uu = NULL;
1532 
1533 	if ((r = sshkey_to_base64(key, &uu)) != 0)
1534 		goto out;
1535 	if ((r = sshbuf_putf(b, "%s %s",
1536 	    sshkey_ssh_name(key), uu)) != 0)
1537 		goto out;
1538 	r = 0;
1539  out:
1540 	free(uu);
1541 	return r;
1542 }
1543 
1544 int
1545 sshkey_write(const struct sshkey *key, FILE *f)
1546 {
1547 	struct sshbuf *b = NULL;
1548 	int r = SSH_ERR_INTERNAL_ERROR;
1549 
1550 	if ((b = sshbuf_new()) == NULL)
1551 		return SSH_ERR_ALLOC_FAIL;
1552 	if ((r = sshkey_format_text(key, b)) != 0)
1553 		goto out;
1554 	if (fwrite(sshbuf_ptr(b), sshbuf_len(b), 1, f) != 1) {
1555 		if (feof(f))
1556 			errno = EPIPE;
1557 		r = SSH_ERR_SYSTEM_ERROR;
1558 		goto out;
1559 	}
1560 	/* Success */
1561 	r = 0;
1562  out:
1563 	sshbuf_free(b);
1564 	return r;
1565 }
1566 
1567 const char *
1568 sshkey_cert_type(const struct sshkey *k)
1569 {
1570 	switch (k->cert->type) {
1571 	case SSH2_CERT_TYPE_USER:
1572 		return "user";
1573 	case SSH2_CERT_TYPE_HOST:
1574 		return "host";
1575 	default:
1576 		return "unknown";
1577 	}
1578 }
1579 
1580 #ifdef WITH_OPENSSL
1581 static int
1582 rsa_generate_private_key(u_int bits, RSA **rsap)
1583 {
1584 	RSA *private = NULL;
1585 	BIGNUM *f4 = NULL;
1586 	int ret = SSH_ERR_INTERNAL_ERROR;
1587 
1588 	if (rsap == NULL)
1589 		return SSH_ERR_INVALID_ARGUMENT;
1590 	if (bits < SSH_RSA_MINIMUM_MODULUS_SIZE ||
1591 	    bits > SSHBUF_MAX_BIGNUM * 8)
1592 		return SSH_ERR_KEY_LENGTH;
1593 	*rsap = NULL;
1594 	if ((private = RSA_new()) == NULL || (f4 = BN_new()) == NULL) {
1595 		ret = SSH_ERR_ALLOC_FAIL;
1596 		goto out;
1597 	}
1598 	if (!BN_set_word(f4, RSA_F4) ||
1599 	    !RSA_generate_key_ex(private, bits, f4, NULL)) {
1600 		ret = SSH_ERR_LIBCRYPTO_ERROR;
1601 		goto out;
1602 	}
1603 	*rsap = private;
1604 	private = NULL;
1605 	ret = 0;
1606  out:
1607 	RSA_free(private);
1608 	BN_free(f4);
1609 	return ret;
1610 }
1611 
1612 static int
1613 dsa_generate_private_key(u_int bits, DSA **dsap)
1614 {
1615 	DSA *private;
1616 	int ret = SSH_ERR_INTERNAL_ERROR;
1617 
1618 	if (dsap == NULL)
1619 		return SSH_ERR_INVALID_ARGUMENT;
1620 	if (bits != 1024)
1621 		return SSH_ERR_KEY_LENGTH;
1622 	if ((private = DSA_new()) == NULL) {
1623 		ret = SSH_ERR_ALLOC_FAIL;
1624 		goto out;
1625 	}
1626 	*dsap = NULL;
1627 	if (!DSA_generate_parameters_ex(private, bits, NULL, 0, NULL,
1628 	    NULL, NULL) || !DSA_generate_key(private)) {
1629 		ret = SSH_ERR_LIBCRYPTO_ERROR;
1630 		goto out;
1631 	}
1632 	*dsap = private;
1633 	private = NULL;
1634 	ret = 0;
1635  out:
1636 	DSA_free(private);
1637 	return ret;
1638 }
1639 
1640 # ifdef OPENSSL_HAS_ECC
1641 int
1642 sshkey_ecdsa_key_to_nid(EC_KEY *k)
1643 {
1644 	EC_GROUP *eg;
1645 	int nids[] = {
1646 		NID_X9_62_prime256v1,
1647 		NID_secp384r1,
1648 #  ifdef OPENSSL_HAS_NISTP521
1649 		NID_secp521r1,
1650 #  endif /* OPENSSL_HAS_NISTP521 */
1651 		-1
1652 	};
1653 	int nid;
1654 	u_int i;
1655 	const EC_GROUP *g = EC_KEY_get0_group(k);
1656 
1657 	/*
1658 	 * The group may be stored in a ASN.1 encoded private key in one of two
1659 	 * ways: as a "named group", which is reconstituted by ASN.1 object ID
1660 	 * or explicit group parameters encoded into the key blob. Only the
1661 	 * "named group" case sets the group NID for us, but we can figure
1662 	 * it out for the other case by comparing against all the groups that
1663 	 * are supported.
1664 	 */
1665 	if ((nid = EC_GROUP_get_curve_name(g)) > 0)
1666 		return nid;
1667 	for (i = 0; nids[i] != -1; i++) {
1668 		if ((eg = EC_GROUP_new_by_curve_name(nids[i])) == NULL)
1669 			return -1;
1670 		if (EC_GROUP_cmp(g, eg, NULL) == 0)
1671 			break;
1672 		EC_GROUP_free(eg);
1673 	}
1674 	if (nids[i] != -1) {
1675 		/* Use the group with the NID attached */
1676 		EC_GROUP_set_asn1_flag(eg, OPENSSL_EC_NAMED_CURVE);
1677 		if (EC_KEY_set_group(k, eg) != 1) {
1678 			EC_GROUP_free(eg);
1679 			return -1;
1680 		}
1681 	}
1682 	return nids[i];
1683 }
1684 
1685 static int
1686 ecdsa_generate_private_key(u_int bits, int *nid, EC_KEY **ecdsap)
1687 {
1688 	EC_KEY *private;
1689 	int ret = SSH_ERR_INTERNAL_ERROR;
1690 
1691 	if (nid == NULL || ecdsap == NULL)
1692 		return SSH_ERR_INVALID_ARGUMENT;
1693 	if ((*nid = sshkey_ecdsa_bits_to_nid(bits)) == -1)
1694 		return SSH_ERR_KEY_LENGTH;
1695 	*ecdsap = NULL;
1696 	if ((private = EC_KEY_new_by_curve_name(*nid)) == NULL) {
1697 		ret = SSH_ERR_ALLOC_FAIL;
1698 		goto out;
1699 	}
1700 	if (EC_KEY_generate_key(private) != 1) {
1701 		ret = SSH_ERR_LIBCRYPTO_ERROR;
1702 		goto out;
1703 	}
1704 	EC_KEY_set_asn1_flag(private, OPENSSL_EC_NAMED_CURVE);
1705 	*ecdsap = private;
1706 	private = NULL;
1707 	ret = 0;
1708  out:
1709 	EC_KEY_free(private);
1710 	return ret;
1711 }
1712 # endif /* OPENSSL_HAS_ECC */
1713 #endif /* WITH_OPENSSL */
1714 
1715 int
1716 sshkey_generate(int type, u_int bits, struct sshkey **keyp)
1717 {
1718 	struct sshkey *k;
1719 	int ret = SSH_ERR_INTERNAL_ERROR;
1720 
1721 	if (keyp == NULL)
1722 		return SSH_ERR_INVALID_ARGUMENT;
1723 	*keyp = NULL;
1724 	if ((k = sshkey_new(KEY_UNSPEC)) == NULL)
1725 		return SSH_ERR_ALLOC_FAIL;
1726 	switch (type) {
1727 	case KEY_ED25519:
1728 		if ((k->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL ||
1729 		    (k->ed25519_sk = malloc(ED25519_SK_SZ)) == NULL) {
1730 			ret = SSH_ERR_ALLOC_FAIL;
1731 			break;
1732 		}
1733 		crypto_sign_ed25519_keypair(k->ed25519_pk, k->ed25519_sk);
1734 		ret = 0;
1735 		break;
1736 #ifdef WITH_XMSS
1737 	case KEY_XMSS:
1738 		ret = sshkey_xmss_generate_private_key(k, bits);
1739 		break;
1740 #endif /* WITH_XMSS */
1741 #ifdef WITH_OPENSSL
1742 	case KEY_DSA:
1743 		ret = dsa_generate_private_key(bits, &k->dsa);
1744 		break;
1745 # ifdef OPENSSL_HAS_ECC
1746 	case KEY_ECDSA:
1747 		ret = ecdsa_generate_private_key(bits, &k->ecdsa_nid,
1748 		    &k->ecdsa);
1749 		break;
1750 # endif /* OPENSSL_HAS_ECC */
1751 	case KEY_RSA:
1752 		ret = rsa_generate_private_key(bits, &k->rsa);
1753 		break;
1754 #endif /* WITH_OPENSSL */
1755 	default:
1756 		ret = SSH_ERR_INVALID_ARGUMENT;
1757 	}
1758 	if (ret == 0) {
1759 		k->type = type;
1760 		*keyp = k;
1761 	} else
1762 		sshkey_free(k);
1763 	return ret;
1764 }
1765 
1766 int
1767 sshkey_cert_copy(const struct sshkey *from_key, struct sshkey *to_key)
1768 {
1769 	u_int i;
1770 	const struct sshkey_cert *from;
1771 	struct sshkey_cert *to;
1772 	int r = SSH_ERR_INTERNAL_ERROR;
1773 
1774 	if (to_key == NULL || (from = from_key->cert) == NULL)
1775 		return SSH_ERR_INVALID_ARGUMENT;
1776 
1777 	if ((to = cert_new()) == NULL)
1778 		return SSH_ERR_ALLOC_FAIL;
1779 
1780 	if ((r = sshbuf_putb(to->certblob, from->certblob)) != 0 ||
1781 	    (r = sshbuf_putb(to->critical, from->critical)) != 0 ||
1782 	    (r = sshbuf_putb(to->extensions, from->extensions)) != 0)
1783 		goto out;
1784 
1785 	to->serial = from->serial;
1786 	to->type = from->type;
1787 	if (from->key_id == NULL)
1788 		to->key_id = NULL;
1789 	else if ((to->key_id = strdup(from->key_id)) == NULL) {
1790 		r = SSH_ERR_ALLOC_FAIL;
1791 		goto out;
1792 	}
1793 	to->valid_after = from->valid_after;
1794 	to->valid_before = from->valid_before;
1795 	if (from->signature_key == NULL)
1796 		to->signature_key = NULL;
1797 	else if ((r = sshkey_from_private(from->signature_key,
1798 	    &to->signature_key)) != 0)
1799 		goto out;
1800 	if (from->signature_type != NULL &&
1801 	    (to->signature_type = strdup(from->signature_type)) == NULL) {
1802 		r = SSH_ERR_ALLOC_FAIL;
1803 		goto out;
1804 	}
1805 	if (from->nprincipals > SSHKEY_CERT_MAX_PRINCIPALS) {
1806 		r = SSH_ERR_INVALID_ARGUMENT;
1807 		goto out;
1808 	}
1809 	if (from->nprincipals > 0) {
1810 		if ((to->principals = calloc(from->nprincipals,
1811 		    sizeof(*to->principals))) == NULL) {
1812 			r = SSH_ERR_ALLOC_FAIL;
1813 			goto out;
1814 		}
1815 		for (i = 0; i < from->nprincipals; i++) {
1816 			to->principals[i] = strdup(from->principals[i]);
1817 			if (to->principals[i] == NULL) {
1818 				to->nprincipals = i;
1819 				r = SSH_ERR_ALLOC_FAIL;
1820 				goto out;
1821 			}
1822 		}
1823 	}
1824 	to->nprincipals = from->nprincipals;
1825 
1826 	/* success */
1827 	cert_free(to_key->cert);
1828 	to_key->cert = to;
1829 	to = NULL;
1830 	r = 0;
1831  out:
1832 	cert_free(to);
1833 	return r;
1834 }
1835 
1836 int
1837 sshkey_from_private(const struct sshkey *k, struct sshkey **pkp)
1838 {
1839 	struct sshkey *n = NULL;
1840 	int r = SSH_ERR_INTERNAL_ERROR;
1841 #ifdef WITH_OPENSSL
1842 	const BIGNUM *rsa_n, *rsa_e;
1843 	BIGNUM *rsa_n_dup = NULL, *rsa_e_dup = NULL;
1844 	const BIGNUM *dsa_p, *dsa_q, *dsa_g, *dsa_pub_key;
1845 	BIGNUM *dsa_p_dup = NULL, *dsa_q_dup = NULL, *dsa_g_dup = NULL;
1846 	BIGNUM *dsa_pub_key_dup = NULL;
1847 #endif /* WITH_OPENSSL */
1848 
1849 	*pkp = NULL;
1850 	if ((n = sshkey_new(k->type)) == NULL) {
1851 		r = SSH_ERR_ALLOC_FAIL;
1852 		goto out;
1853 	}
1854 	switch (k->type) {
1855 #ifdef WITH_OPENSSL
1856 	case KEY_DSA:
1857 	case KEY_DSA_CERT:
1858 		DSA_get0_pqg(k->dsa, &dsa_p, &dsa_q, &dsa_g);
1859 		DSA_get0_key(k->dsa, &dsa_pub_key, NULL);
1860 		if ((dsa_p_dup = BN_dup(dsa_p)) == NULL ||
1861 		    (dsa_q_dup = BN_dup(dsa_q)) == NULL ||
1862 		    (dsa_g_dup = BN_dup(dsa_g)) == NULL ||
1863 		    (dsa_pub_key_dup = BN_dup(dsa_pub_key)) == NULL) {
1864 			r = SSH_ERR_ALLOC_FAIL;
1865 			goto out;
1866 		}
1867 		if (!DSA_set0_pqg(n->dsa, dsa_p_dup, dsa_q_dup, dsa_g_dup)) {
1868 			r = SSH_ERR_LIBCRYPTO_ERROR;
1869 			goto out;
1870 		}
1871 		dsa_p_dup = dsa_q_dup = dsa_g_dup = NULL; /* transferred */
1872 		if (!DSA_set0_key(n->dsa, dsa_pub_key_dup, NULL)) {
1873 			r = SSH_ERR_LIBCRYPTO_ERROR;
1874 			goto out;
1875 		}
1876 		dsa_pub_key_dup = NULL; /* transferred */
1877 
1878 		break;
1879 # ifdef OPENSSL_HAS_ECC
1880 	case KEY_ECDSA:
1881 	case KEY_ECDSA_CERT:
1882 	case KEY_ECDSA_SK:
1883 	case KEY_ECDSA_SK_CERT:
1884 		n->ecdsa_nid = k->ecdsa_nid;
1885 		n->ecdsa = EC_KEY_new_by_curve_name(k->ecdsa_nid);
1886 		if (n->ecdsa == NULL) {
1887 			r = SSH_ERR_ALLOC_FAIL;
1888 			goto out;
1889 		}
1890 		if (EC_KEY_set_public_key(n->ecdsa,
1891 		    EC_KEY_get0_public_key(k->ecdsa)) != 1) {
1892 			r = SSH_ERR_LIBCRYPTO_ERROR;
1893 			goto out;
1894 		}
1895 		if (k->type != KEY_ECDSA_SK && k->type != KEY_ECDSA_SK_CERT)
1896 			break;
1897 		/* Append security-key application string */
1898 		if ((n->sk_application = strdup(k->sk_application)) == NULL)
1899 			goto out;
1900 		break;
1901 # endif /* OPENSSL_HAS_ECC */
1902 	case KEY_RSA:
1903 	case KEY_RSA_CERT:
1904 		RSA_get0_key(k->rsa, &rsa_n, &rsa_e, NULL);
1905 		if ((rsa_n_dup = BN_dup(rsa_n)) == NULL ||
1906 		    (rsa_e_dup = BN_dup(rsa_e)) == NULL) {
1907 			r = SSH_ERR_ALLOC_FAIL;
1908 			goto out;
1909 		}
1910 		if (!RSA_set0_key(n->rsa, rsa_n_dup, rsa_e_dup, NULL)) {
1911 			r = SSH_ERR_LIBCRYPTO_ERROR;
1912 			goto out;
1913 		}
1914 		rsa_n_dup = rsa_e_dup = NULL; /* transferred */
1915 		break;
1916 #endif /* WITH_OPENSSL */
1917 	case KEY_ED25519:
1918 	case KEY_ED25519_CERT:
1919 	case KEY_ED25519_SK:
1920 	case KEY_ED25519_SK_CERT:
1921 		if (k->ed25519_pk != NULL) {
1922 			if ((n->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL) {
1923 				r = SSH_ERR_ALLOC_FAIL;
1924 				goto out;
1925 			}
1926 			memcpy(n->ed25519_pk, k->ed25519_pk, ED25519_PK_SZ);
1927 		}
1928 		if (k->type != KEY_ED25519_SK &&
1929 		    k->type != KEY_ED25519_SK_CERT)
1930 			break;
1931 		/* Append security-key application string */
1932 		if ((n->sk_application = strdup(k->sk_application)) == NULL)
1933 			goto out;
1934 		break;
1935 #ifdef WITH_XMSS
1936 	case KEY_XMSS:
1937 	case KEY_XMSS_CERT:
1938 		if ((r = sshkey_xmss_init(n, k->xmss_name)) != 0)
1939 			goto out;
1940 		if (k->xmss_pk != NULL) {
1941 			u_int32_t left;
1942 			size_t pklen = sshkey_xmss_pklen(k);
1943 			if (pklen == 0 || sshkey_xmss_pklen(n) != pklen) {
1944 				r = SSH_ERR_INTERNAL_ERROR;
1945 				goto out;
1946 			}
1947 			if ((n->xmss_pk = malloc(pklen)) == NULL) {
1948 				r = SSH_ERR_ALLOC_FAIL;
1949 				goto out;
1950 			}
1951 			memcpy(n->xmss_pk, k->xmss_pk, pklen);
1952 			/* simulate number of signatures left on pubkey */
1953 			left = sshkey_xmss_signatures_left(k);
1954 			if (left)
1955 				sshkey_xmss_enable_maxsign(n, left);
1956 		}
1957 		break;
1958 #endif /* WITH_XMSS */
1959 	default:
1960 		r = SSH_ERR_KEY_TYPE_UNKNOWN;
1961 		goto out;
1962 	}
1963 	if (sshkey_is_cert(k) && (r = sshkey_cert_copy(k, n)) != 0)
1964 		goto out;
1965 	/* success */
1966 	*pkp = n;
1967 	n = NULL;
1968 	r = 0;
1969  out:
1970 	sshkey_free(n);
1971 #ifdef WITH_OPENSSL
1972 	BN_clear_free(rsa_n_dup);
1973 	BN_clear_free(rsa_e_dup);
1974 	BN_clear_free(dsa_p_dup);
1975 	BN_clear_free(dsa_q_dup);
1976 	BN_clear_free(dsa_g_dup);
1977 	BN_clear_free(dsa_pub_key_dup);
1978 #endif
1979 
1980 	return r;
1981 }
1982 
1983 int
1984 sshkey_is_shielded(struct sshkey *k)
1985 {
1986 	return k != NULL && k->shielded_private != NULL;
1987 }
1988 
1989 int
1990 sshkey_shield_private(struct sshkey *k)
1991 {
1992 	struct sshbuf *prvbuf = NULL;
1993 	u_char *prekey = NULL, *enc = NULL, keyiv[SSH_DIGEST_MAX_LENGTH];
1994 	struct sshcipher_ctx *cctx = NULL;
1995 	const struct sshcipher *cipher;
1996 	size_t i, enclen = 0;
1997 	struct sshkey *kswap = NULL, tmp;
1998 	int r = SSH_ERR_INTERNAL_ERROR;
1999 
2000 #ifdef DEBUG_PK
2001 	fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k));
2002 #endif
2003 	if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) {
2004 		r = SSH_ERR_INVALID_ARGUMENT;
2005 		goto out;
2006 	}
2007 	if (cipher_keylen(cipher) + cipher_ivlen(cipher) >
2008 	    ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) {
2009 		r = SSH_ERR_INTERNAL_ERROR;
2010 		goto out;
2011 	}
2012 
2013 	/* Prepare a random pre-key, and from it an ephemeral key */
2014 	if ((prekey = malloc(SSHKEY_SHIELD_PREKEY_LEN)) == NULL) {
2015 		r = SSH_ERR_ALLOC_FAIL;
2016 		goto out;
2017 	}
2018 	arc4random_buf(prekey, SSHKEY_SHIELD_PREKEY_LEN);
2019 	if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH,
2020 	    prekey, SSHKEY_SHIELD_PREKEY_LEN,
2021 	    keyiv, SSH_DIGEST_MAX_LENGTH)) != 0)
2022 		goto out;
2023 #ifdef DEBUG_PK
2024 	fprintf(stderr, "%s: key+iv\n", __func__);
2025 	sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH),
2026 	    stderr);
2027 #endif
2028 	if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher),
2029 	    keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 1)) != 0)
2030 		goto out;
2031 
2032 	/* Serialise and encrypt the private key using the ephemeral key */
2033 	if ((prvbuf = sshbuf_new()) == NULL) {
2034 		r = SSH_ERR_ALLOC_FAIL;
2035 		goto out;
2036 	}
2037 	if (sshkey_is_shielded(k) && (r = sshkey_unshield_private(k)) != 0)
2038 		goto out;
2039 	if ((r = sshkey_private_serialize_opt(k, prvbuf,
2040 	     SSHKEY_SERIALIZE_SHIELD)) != 0)
2041 		goto out;
2042 	/* pad to cipher blocksize */
2043 	i = 0;
2044 	while (sshbuf_len(prvbuf) % cipher_blocksize(cipher)) {
2045 		if ((r = sshbuf_put_u8(prvbuf, ++i & 0xff)) != 0)
2046 			goto out;
2047 	}
2048 #ifdef DEBUG_PK
2049 	fprintf(stderr, "%s: serialised\n", __func__);
2050 	sshbuf_dump(prvbuf, stderr);
2051 #endif
2052 	/* encrypt */
2053 	enclen = sshbuf_len(prvbuf);
2054 	if ((enc = malloc(enclen)) == NULL) {
2055 		r = SSH_ERR_ALLOC_FAIL;
2056 		goto out;
2057 	}
2058 	if ((r = cipher_crypt(cctx, 0, enc,
2059 	    sshbuf_ptr(prvbuf), sshbuf_len(prvbuf), 0, 0)) != 0)
2060 		goto out;
2061 #ifdef DEBUG_PK
2062 	fprintf(stderr, "%s: encrypted\n", __func__);
2063 	sshbuf_dump_data(enc, enclen, stderr);
2064 #endif
2065 
2066 	/* Make a scrubbed, public-only copy of our private key argument */
2067 	if ((r = sshkey_from_private(k, &kswap)) != 0)
2068 		goto out;
2069 
2070 	/* Swap the private key out (it will be destroyed below) */
2071 	tmp = *kswap;
2072 	*kswap = *k;
2073 	*k = tmp;
2074 
2075 	/* Insert the shielded key into our argument */
2076 	k->shielded_private = enc;
2077 	k->shielded_len = enclen;
2078 	k->shield_prekey = prekey;
2079 	k->shield_prekey_len = SSHKEY_SHIELD_PREKEY_LEN;
2080 	enc = prekey = NULL; /* transferred */
2081 	enclen = 0;
2082 
2083 	/* preserve key fields that are required for correct operation */
2084 	k->sk_flags = kswap->sk_flags;
2085 
2086 	/* success */
2087 	r = 0;
2088 
2089  out:
2090 	/* XXX behaviour on error - invalidate original private key? */
2091 	cipher_free(cctx);
2092 	explicit_bzero(keyiv, sizeof(keyiv));
2093 	explicit_bzero(&tmp, sizeof(tmp));
2094 	freezero(enc, enclen);
2095 	freezero(prekey, SSHKEY_SHIELD_PREKEY_LEN);
2096 	sshkey_free(kswap);
2097 	sshbuf_free(prvbuf);
2098 	return r;
2099 }
2100 
2101 int
2102 sshkey_unshield_private(struct sshkey *k)
2103 {
2104 	struct sshbuf *prvbuf = NULL;
2105 	u_char pad, *cp, keyiv[SSH_DIGEST_MAX_LENGTH];
2106 	struct sshcipher_ctx *cctx = NULL;
2107 	const struct sshcipher *cipher;
2108 	size_t i;
2109 	struct sshkey *kswap = NULL, tmp;
2110 	int r = SSH_ERR_INTERNAL_ERROR;
2111 
2112 #ifdef DEBUG_PK
2113 	fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k));
2114 #endif
2115 	if (!sshkey_is_shielded(k))
2116 		return 0; /* nothing to do */
2117 
2118 	if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) {
2119 		r = SSH_ERR_INVALID_ARGUMENT;
2120 		goto out;
2121 	}
2122 	if (cipher_keylen(cipher) + cipher_ivlen(cipher) >
2123 	    ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) {
2124 		r = SSH_ERR_INTERNAL_ERROR;
2125 		goto out;
2126 	}
2127 	/* check size of shielded key blob */
2128 	if (k->shielded_len < cipher_blocksize(cipher) ||
2129 	    (k->shielded_len % cipher_blocksize(cipher)) != 0) {
2130 		r = SSH_ERR_INVALID_FORMAT;
2131 		goto out;
2132 	}
2133 
2134 	/* Calculate the ephemeral key from the prekey */
2135 	if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH,
2136 	    k->shield_prekey, k->shield_prekey_len,
2137 	    keyiv, SSH_DIGEST_MAX_LENGTH)) != 0)
2138 		goto out;
2139 	if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher),
2140 	    keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 0)) != 0)
2141 		goto out;
2142 #ifdef DEBUG_PK
2143 	fprintf(stderr, "%s: key+iv\n", __func__);
2144 	sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH),
2145 	    stderr);
2146 #endif
2147 
2148 	/* Decrypt and parse the shielded private key using the ephemeral key */
2149 	if ((prvbuf = sshbuf_new()) == NULL) {
2150 		r = SSH_ERR_ALLOC_FAIL;
2151 		goto out;
2152 	}
2153 	if ((r = sshbuf_reserve(prvbuf, k->shielded_len, &cp)) != 0)
2154 		goto out;
2155 	/* decrypt */
2156 #ifdef DEBUG_PK
2157 	fprintf(stderr, "%s: encrypted\n", __func__);
2158 	sshbuf_dump_data(k->shielded_private, k->shielded_len, stderr);
2159 #endif
2160 	if ((r = cipher_crypt(cctx, 0, cp,
2161 	    k->shielded_private, k->shielded_len, 0, 0)) != 0)
2162 		goto out;
2163 #ifdef DEBUG_PK
2164 	fprintf(stderr, "%s: serialised\n", __func__);
2165 	sshbuf_dump(prvbuf, stderr);
2166 #endif
2167 	/* Parse private key */
2168 	if ((r = sshkey_private_deserialize(prvbuf, &kswap)) != 0)
2169 		goto out;
2170 	/* Check deterministic padding */
2171 	i = 0;
2172 	while (sshbuf_len(prvbuf)) {
2173 		if ((r = sshbuf_get_u8(prvbuf, &pad)) != 0)
2174 			goto out;
2175 		if (pad != (++i & 0xff)) {
2176 			r = SSH_ERR_INVALID_FORMAT;
2177 			goto out;
2178 		}
2179 	}
2180 
2181 	/* Swap the parsed key back into place */
2182 	tmp = *kswap;
2183 	*kswap = *k;
2184 	*k = tmp;
2185 
2186 	/* success */
2187 	r = 0;
2188 
2189  out:
2190 	cipher_free(cctx);
2191 	explicit_bzero(keyiv, sizeof(keyiv));
2192 	explicit_bzero(&tmp, sizeof(tmp));
2193 	sshkey_free(kswap);
2194 	sshbuf_free(prvbuf);
2195 	return r;
2196 }
2197 
2198 static int
2199 cert_parse(struct sshbuf *b, struct sshkey *key, struct sshbuf *certbuf)
2200 {
2201 	struct sshbuf *principals = NULL, *crit = NULL;
2202 	struct sshbuf *exts = NULL, *ca = NULL;
2203 	u_char *sig = NULL;
2204 	size_t signed_len = 0, slen = 0, kidlen = 0;
2205 	int ret = SSH_ERR_INTERNAL_ERROR;
2206 
2207 	/* Copy the entire key blob for verification and later serialisation */
2208 	if ((ret = sshbuf_putb(key->cert->certblob, certbuf)) != 0)
2209 		return ret;
2210 
2211 	/* Parse body of certificate up to signature */
2212 	if ((ret = sshbuf_get_u64(b, &key->cert->serial)) != 0 ||
2213 	    (ret = sshbuf_get_u32(b, &key->cert->type)) != 0 ||
2214 	    (ret = sshbuf_get_cstring(b, &key->cert->key_id, &kidlen)) != 0 ||
2215 	    (ret = sshbuf_froms(b, &principals)) != 0 ||
2216 	    (ret = sshbuf_get_u64(b, &key->cert->valid_after)) != 0 ||
2217 	    (ret = sshbuf_get_u64(b, &key->cert->valid_before)) != 0 ||
2218 	    (ret = sshbuf_froms(b, &crit)) != 0 ||
2219 	    (ret = sshbuf_froms(b, &exts)) != 0 ||
2220 	    (ret = sshbuf_get_string_direct(b, NULL, NULL)) != 0 ||
2221 	    (ret = sshbuf_froms(b, &ca)) != 0) {
2222 		/* XXX debug print error for ret */
2223 		ret = SSH_ERR_INVALID_FORMAT;
2224 		goto out;
2225 	}
2226 
2227 	/* Signature is left in the buffer so we can calculate this length */
2228 	signed_len = sshbuf_len(key->cert->certblob) - sshbuf_len(b);
2229 
2230 	if ((ret = sshbuf_get_string(b, &sig, &slen)) != 0) {
2231 		ret = SSH_ERR_INVALID_FORMAT;
2232 		goto out;
2233 	}
2234 
2235 	if (key->cert->type != SSH2_CERT_TYPE_USER &&
2236 	    key->cert->type != SSH2_CERT_TYPE_HOST) {
2237 		ret = SSH_ERR_KEY_CERT_UNKNOWN_TYPE;
2238 		goto out;
2239 	}
2240 
2241 	/* Parse principals section */
2242 	while (sshbuf_len(principals) > 0) {
2243 		char *principal = NULL;
2244 		char **oprincipals = NULL;
2245 
2246 		if (key->cert->nprincipals >= SSHKEY_CERT_MAX_PRINCIPALS) {
2247 			ret = SSH_ERR_INVALID_FORMAT;
2248 			goto out;
2249 		}
2250 		if ((ret = sshbuf_get_cstring(principals, &principal,
2251 		    NULL)) != 0) {
2252 			ret = SSH_ERR_INVALID_FORMAT;
2253 			goto out;
2254 		}
2255 		oprincipals = key->cert->principals;
2256 		key->cert->principals = recallocarray(key->cert->principals,
2257 		    key->cert->nprincipals, key->cert->nprincipals + 1,
2258 		    sizeof(*key->cert->principals));
2259 		if (key->cert->principals == NULL) {
2260 			free(principal);
2261 			key->cert->principals = oprincipals;
2262 			ret = SSH_ERR_ALLOC_FAIL;
2263 			goto out;
2264 		}
2265 		key->cert->principals[key->cert->nprincipals++] = principal;
2266 	}
2267 
2268 	/*
2269 	 * Stash a copies of the critical options and extensions sections
2270 	 * for later use.
2271 	 */
2272 	if ((ret = sshbuf_putb(key->cert->critical, crit)) != 0 ||
2273 	    (exts != NULL &&
2274 	    (ret = sshbuf_putb(key->cert->extensions, exts)) != 0))
2275 		goto out;
2276 
2277 	/*
2278 	 * Validate critical options and extensions sections format.
2279 	 */
2280 	while (sshbuf_len(crit) != 0) {
2281 		if ((ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0 ||
2282 		    (ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0) {
2283 			sshbuf_reset(key->cert->critical);
2284 			ret = SSH_ERR_INVALID_FORMAT;
2285 			goto out;
2286 		}
2287 	}
2288 	while (exts != NULL && sshbuf_len(exts) != 0) {
2289 		if ((ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0 ||
2290 		    (ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0) {
2291 			sshbuf_reset(key->cert->extensions);
2292 			ret = SSH_ERR_INVALID_FORMAT;
2293 			goto out;
2294 		}
2295 	}
2296 
2297 	/* Parse CA key and check signature */
2298 	if (sshkey_from_blob_internal(ca, &key->cert->signature_key, 0) != 0) {
2299 		ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
2300 		goto out;
2301 	}
2302 	if (!sshkey_type_is_valid_ca(key->cert->signature_key->type)) {
2303 		ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
2304 		goto out;
2305 	}
2306 	if ((ret = sshkey_verify(key->cert->signature_key, sig, slen,
2307 	    sshbuf_ptr(key->cert->certblob), signed_len, NULL, 0, NULL)) != 0)
2308 		goto out;
2309 	if ((ret = sshkey_get_sigtype(sig, slen,
2310 	    &key->cert->signature_type)) != 0)
2311 		goto out;
2312 
2313 	/* Success */
2314 	ret = 0;
2315  out:
2316 	sshbuf_free(ca);
2317 	sshbuf_free(crit);
2318 	sshbuf_free(exts);
2319 	sshbuf_free(principals);
2320 	free(sig);
2321 	return ret;
2322 }
2323 
2324 #ifdef WITH_OPENSSL
2325 static int
2326 check_rsa_length(const RSA *rsa)
2327 {
2328 	const BIGNUM *rsa_n;
2329 
2330 	RSA_get0_key(rsa, &rsa_n, NULL, NULL);
2331 	if (BN_num_bits(rsa_n) < SSH_RSA_MINIMUM_MODULUS_SIZE)
2332 		return SSH_ERR_KEY_LENGTH;
2333 	return 0;
2334 }
2335 #endif
2336 
2337 static int
2338 sshkey_from_blob_internal(struct sshbuf *b, struct sshkey **keyp,
2339     int allow_cert)
2340 {
2341 	int type, ret = SSH_ERR_INTERNAL_ERROR;
2342 	char *ktype = NULL, *curve = NULL, *xmss_name = NULL;
2343 	struct sshkey *key = NULL;
2344 	size_t len;
2345 	u_char *pk = NULL;
2346 	struct sshbuf *copy;
2347 #if defined(WITH_OPENSSL)
2348 	BIGNUM *rsa_n = NULL, *rsa_e = NULL;
2349 	BIGNUM *dsa_p = NULL, *dsa_q = NULL, *dsa_g = NULL, *dsa_pub_key = NULL;
2350 # if defined(OPENSSL_HAS_ECC)
2351 	EC_POINT *q = NULL;
2352 # endif /* OPENSSL_HAS_ECC */
2353 #endif /* WITH_OPENSSL */
2354 
2355 #ifdef DEBUG_PK /* XXX */
2356 	sshbuf_dump(b, stderr);
2357 #endif
2358 	if (keyp != NULL)
2359 		*keyp = NULL;
2360 	if ((copy = sshbuf_fromb(b)) == NULL) {
2361 		ret = SSH_ERR_ALLOC_FAIL;
2362 		goto out;
2363 	}
2364 	if (sshbuf_get_cstring(b, &ktype, NULL) != 0) {
2365 		ret = SSH_ERR_INVALID_FORMAT;
2366 		goto out;
2367 	}
2368 
2369 	type = sshkey_type_from_name(ktype);
2370 	if (!allow_cert && sshkey_type_is_cert(type)) {
2371 		ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
2372 		goto out;
2373 	}
2374 	switch (type) {
2375 #ifdef WITH_OPENSSL
2376 	case KEY_RSA_CERT:
2377 		/* Skip nonce */
2378 		if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
2379 			ret = SSH_ERR_INVALID_FORMAT;
2380 			goto out;
2381 		}
2382 		/* FALLTHROUGH */
2383 	case KEY_RSA:
2384 		if ((key = sshkey_new(type)) == NULL) {
2385 			ret = SSH_ERR_ALLOC_FAIL;
2386 			goto out;
2387 		}
2388 		if (sshbuf_get_bignum2(b, &rsa_e) != 0 ||
2389 		    sshbuf_get_bignum2(b, &rsa_n) != 0) {
2390 			ret = SSH_ERR_INVALID_FORMAT;
2391 			goto out;
2392 		}
2393 		if (!RSA_set0_key(key->rsa, rsa_n, rsa_e, NULL)) {
2394 			ret = SSH_ERR_LIBCRYPTO_ERROR;
2395 			goto out;
2396 		}
2397 		rsa_n = rsa_e = NULL; /* transferred */
2398 		if ((ret = check_rsa_length(key->rsa)) != 0)
2399 			goto out;
2400 #ifdef DEBUG_PK
2401 		RSA_print_fp(stderr, key->rsa, 8);
2402 #endif
2403 		break;
2404 	case KEY_DSA_CERT:
2405 		/* Skip nonce */
2406 		if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
2407 			ret = SSH_ERR_INVALID_FORMAT;
2408 			goto out;
2409 		}
2410 		/* FALLTHROUGH */
2411 	case KEY_DSA:
2412 		if ((key = sshkey_new(type)) == NULL) {
2413 			ret = SSH_ERR_ALLOC_FAIL;
2414 			goto out;
2415 		}
2416 		if (sshbuf_get_bignum2(b, &dsa_p) != 0 ||
2417 		    sshbuf_get_bignum2(b, &dsa_q) != 0 ||
2418 		    sshbuf_get_bignum2(b, &dsa_g) != 0 ||
2419 		    sshbuf_get_bignum2(b, &dsa_pub_key) != 0) {
2420 			ret = SSH_ERR_INVALID_FORMAT;
2421 			goto out;
2422 		}
2423 		if (!DSA_set0_pqg(key->dsa, dsa_p, dsa_q, dsa_g)) {
2424 			ret = SSH_ERR_LIBCRYPTO_ERROR;
2425 			goto out;
2426 		}
2427 		dsa_p = dsa_q = dsa_g = NULL; /* transferred */
2428 		if (!DSA_set0_key(key->dsa, dsa_pub_key, NULL)) {
2429 			ret = SSH_ERR_LIBCRYPTO_ERROR;
2430 			goto out;
2431 		}
2432 		dsa_pub_key = NULL; /* transferred */
2433 #ifdef DEBUG_PK
2434 		DSA_print_fp(stderr, key->dsa, 8);
2435 #endif
2436 		break;
2437 # ifdef OPENSSL_HAS_ECC
2438 	case KEY_ECDSA_CERT:
2439 	case KEY_ECDSA_SK_CERT:
2440 		/* Skip nonce */
2441 		if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
2442 			ret = SSH_ERR_INVALID_FORMAT;
2443 			goto out;
2444 		}
2445 		/* FALLTHROUGH */
2446 	case KEY_ECDSA:
2447 	case KEY_ECDSA_SK:
2448 		if ((key = sshkey_new(type)) == NULL) {
2449 			ret = SSH_ERR_ALLOC_FAIL;
2450 			goto out;
2451 		}
2452 		key->ecdsa_nid = sshkey_ecdsa_nid_from_name(ktype);
2453 		if (sshbuf_get_cstring(b, &curve, NULL) != 0) {
2454 			ret = SSH_ERR_INVALID_FORMAT;
2455 			goto out;
2456 		}
2457 		if (key->ecdsa_nid != sshkey_curve_name_to_nid(curve)) {
2458 			ret = SSH_ERR_EC_CURVE_MISMATCH;
2459 			goto out;
2460 		}
2461 		EC_KEY_free(key->ecdsa);
2462 		if ((key->ecdsa = EC_KEY_new_by_curve_name(key->ecdsa_nid))
2463 		    == NULL) {
2464 			ret = SSH_ERR_EC_CURVE_INVALID;
2465 			goto out;
2466 		}
2467 		if ((q = EC_POINT_new(EC_KEY_get0_group(key->ecdsa))) == NULL) {
2468 			ret = SSH_ERR_ALLOC_FAIL;
2469 			goto out;
2470 		}
2471 		if (sshbuf_get_ec(b, q, EC_KEY_get0_group(key->ecdsa)) != 0) {
2472 			ret = SSH_ERR_INVALID_FORMAT;
2473 			goto out;
2474 		}
2475 		if (sshkey_ec_validate_public(EC_KEY_get0_group(key->ecdsa),
2476 		    q) != 0) {
2477 			ret = SSH_ERR_KEY_INVALID_EC_VALUE;
2478 			goto out;
2479 		}
2480 		if (EC_KEY_set_public_key(key->ecdsa, q) != 1) {
2481 			/* XXX assume it is a allocation error */
2482 			ret = SSH_ERR_ALLOC_FAIL;
2483 			goto out;
2484 		}
2485 #ifdef DEBUG_PK
2486 		sshkey_dump_ec_point(EC_KEY_get0_group(key->ecdsa), q);
2487 #endif
2488 		if (type == KEY_ECDSA_SK || type == KEY_ECDSA_SK_CERT) {
2489 			/* Parse additional security-key application string */
2490 			if (sshbuf_get_cstring(b, &key->sk_application,
2491 			    NULL) != 0) {
2492 				ret = SSH_ERR_INVALID_FORMAT;
2493 				goto out;
2494 			}
2495 #ifdef DEBUG_PK
2496 			fprintf(stderr, "App: %s\n", key->sk_application);
2497 #endif
2498 		}
2499 		break;
2500 # endif /* OPENSSL_HAS_ECC */
2501 #endif /* WITH_OPENSSL */
2502 	case KEY_ED25519_CERT:
2503 	case KEY_ED25519_SK_CERT:
2504 		/* Skip nonce */
2505 		if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
2506 			ret = SSH_ERR_INVALID_FORMAT;
2507 			goto out;
2508 		}
2509 		/* FALLTHROUGH */
2510 	case KEY_ED25519:
2511 	case KEY_ED25519_SK:
2512 		if ((ret = sshbuf_get_string(b, &pk, &len)) != 0)
2513 			goto out;
2514 		if (len != ED25519_PK_SZ) {
2515 			ret = SSH_ERR_INVALID_FORMAT;
2516 			goto out;
2517 		}
2518 		if ((key = sshkey_new(type)) == NULL) {
2519 			ret = SSH_ERR_ALLOC_FAIL;
2520 			goto out;
2521 		}
2522 		if (type == KEY_ED25519_SK || type == KEY_ED25519_SK_CERT) {
2523 			/* Parse additional security-key application string */
2524 			if (sshbuf_get_cstring(b, &key->sk_application,
2525 			    NULL) != 0) {
2526 				ret = SSH_ERR_INVALID_FORMAT;
2527 				goto out;
2528 			}
2529 #ifdef DEBUG_PK
2530 			fprintf(stderr, "App: %s\n", key->sk_application);
2531 #endif
2532 		}
2533 		key->ed25519_pk = pk;
2534 		pk = NULL;
2535 		break;
2536 #ifdef WITH_XMSS
2537 	case KEY_XMSS_CERT:
2538 		/* Skip nonce */
2539 		if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
2540 			ret = SSH_ERR_INVALID_FORMAT;
2541 			goto out;
2542 		}
2543 		/* FALLTHROUGH */
2544 	case KEY_XMSS:
2545 		if ((ret = sshbuf_get_cstring(b, &xmss_name, NULL)) != 0)
2546 			goto out;
2547 		if ((key = sshkey_new(type)) == NULL) {
2548 			ret = SSH_ERR_ALLOC_FAIL;
2549 			goto out;
2550 		}
2551 		if ((ret = sshkey_xmss_init(key, xmss_name)) != 0)
2552 			goto out;
2553 		if ((ret = sshbuf_get_string(b, &pk, &len)) != 0)
2554 			goto out;
2555 		if (len == 0 || len != sshkey_xmss_pklen(key)) {
2556 			ret = SSH_ERR_INVALID_FORMAT;
2557 			goto out;
2558 		}
2559 		key->xmss_pk = pk;
2560 		pk = NULL;
2561 		if (type != KEY_XMSS_CERT &&
2562 		    (ret = sshkey_xmss_deserialize_pk_info(key, b)) != 0)
2563 			goto out;
2564 		break;
2565 #endif /* WITH_XMSS */
2566 	case KEY_UNSPEC:
2567 	default:
2568 		ret = SSH_ERR_KEY_TYPE_UNKNOWN;
2569 		goto out;
2570 	}
2571 
2572 	/* Parse certificate potion */
2573 	if (sshkey_is_cert(key) && (ret = cert_parse(b, key, copy)) != 0)
2574 		goto out;
2575 
2576 	if (key != NULL && sshbuf_len(b) != 0) {
2577 		ret = SSH_ERR_INVALID_FORMAT;
2578 		goto out;
2579 	}
2580 	ret = 0;
2581 	if (keyp != NULL) {
2582 		*keyp = key;
2583 		key = NULL;
2584 	}
2585  out:
2586 	sshbuf_free(copy);
2587 	sshkey_free(key);
2588 	free(xmss_name);
2589 	free(ktype);
2590 	free(curve);
2591 	free(pk);
2592 #if defined(WITH_OPENSSL)
2593 	BN_clear_free(rsa_n);
2594 	BN_clear_free(rsa_e);
2595 	BN_clear_free(dsa_p);
2596 	BN_clear_free(dsa_q);
2597 	BN_clear_free(dsa_g);
2598 	BN_clear_free(dsa_pub_key);
2599 # if defined(OPENSSL_HAS_ECC)
2600 	EC_POINT_free(q);
2601 # endif /* OPENSSL_HAS_ECC */
2602 #endif /* WITH_OPENSSL */
2603 	return ret;
2604 }
2605 
2606 int
2607 sshkey_from_blob(const u_char *blob, size_t blen, struct sshkey **keyp)
2608 {
2609 	struct sshbuf *b;
2610 	int r;
2611 
2612 	if ((b = sshbuf_from(blob, blen)) == NULL)
2613 		return SSH_ERR_ALLOC_FAIL;
2614 	r = sshkey_from_blob_internal(b, keyp, 1);
2615 	sshbuf_free(b);
2616 	return r;
2617 }
2618 
2619 int
2620 sshkey_fromb(struct sshbuf *b, struct sshkey **keyp)
2621 {
2622 	return sshkey_from_blob_internal(b, keyp, 1);
2623 }
2624 
2625 int
2626 sshkey_froms(struct sshbuf *buf, struct sshkey **keyp)
2627 {
2628 	struct sshbuf *b;
2629 	int r;
2630 
2631 	if ((r = sshbuf_froms(buf, &b)) != 0)
2632 		return r;
2633 	r = sshkey_from_blob_internal(b, keyp, 1);
2634 	sshbuf_free(b);
2635 	return r;
2636 }
2637 
2638 int
2639 sshkey_get_sigtype(const u_char *sig, size_t siglen, char **sigtypep)
2640 {
2641 	int r;
2642 	struct sshbuf *b = NULL;
2643 	char *sigtype = NULL;
2644 
2645 	if (sigtypep != NULL)
2646 		*sigtypep = NULL;
2647 	if ((b = sshbuf_from(sig, siglen)) == NULL)
2648 		return SSH_ERR_ALLOC_FAIL;
2649 	if ((r = sshbuf_get_cstring(b, &sigtype, NULL)) != 0)
2650 		goto out;
2651 	/* success */
2652 	if (sigtypep != NULL) {
2653 		*sigtypep = sigtype;
2654 		sigtype = NULL;
2655 	}
2656 	r = 0;
2657  out:
2658 	free(sigtype);
2659 	sshbuf_free(b);
2660 	return r;
2661 }
2662 
2663 /*
2664  *
2665  * Checks whether a certificate's signature type is allowed.
2666  * Returns 0 (success) if the certificate signature type appears in the
2667  * "allowed" pattern-list, or the key is not a certificate to begin with.
2668  * Otherwise returns a ssherr.h code.
2669  */
2670 int
2671 sshkey_check_cert_sigtype(const struct sshkey *key, const char *allowed)
2672 {
2673 	if (key == NULL || allowed == NULL)
2674 		return SSH_ERR_INVALID_ARGUMENT;
2675 	if (!sshkey_type_is_cert(key->type))
2676 		return 0;
2677 	if (key->cert == NULL || key->cert->signature_type == NULL)
2678 		return SSH_ERR_INVALID_ARGUMENT;
2679 	if (match_pattern_list(key->cert->signature_type, allowed, 0) != 1)
2680 		return SSH_ERR_SIGN_ALG_UNSUPPORTED;
2681 	return 0;
2682 }
2683 
2684 /*
2685  * Returns the expected signature algorithm for a given public key algorithm.
2686  */
2687 const char *
2688 sshkey_sigalg_by_name(const char *name)
2689 {
2690 	const struct keytype *kt;
2691 
2692 	for (kt = keytypes; kt->type != -1; kt++) {
2693 		if (strcmp(kt->name, name) != 0)
2694 			continue;
2695 		if (kt->sigalg != NULL)
2696 			return kt->sigalg;
2697 		if (!kt->cert)
2698 			return kt->name;
2699 		return sshkey_ssh_name_from_type_nid(
2700 		    sshkey_type_plain(kt->type), kt->nid);
2701 	}
2702 	return NULL;
2703 }
2704 
2705 /*
2706  * Verifies that the signature algorithm appearing inside the signature blob
2707  * matches that which was requested.
2708  */
2709 int
2710 sshkey_check_sigtype(const u_char *sig, size_t siglen,
2711     const char *requested_alg)
2712 {
2713 	const char *expected_alg;
2714 	char *sigtype = NULL;
2715 	int r;
2716 
2717 	if (requested_alg == NULL)
2718 		return 0;
2719 	if ((expected_alg = sshkey_sigalg_by_name(requested_alg)) == NULL)
2720 		return SSH_ERR_INVALID_ARGUMENT;
2721 	if ((r = sshkey_get_sigtype(sig, siglen, &sigtype)) != 0)
2722 		return r;
2723 	r = strcmp(expected_alg, sigtype) == 0;
2724 	free(sigtype);
2725 	return r ? 0 : SSH_ERR_SIGN_ALG_UNSUPPORTED;
2726 }
2727 
2728 int
2729 sshkey_sign(struct sshkey *key,
2730     u_char **sigp, size_t *lenp,
2731     const u_char *data, size_t datalen,
2732     const char *alg, const char *sk_provider, u_int compat)
2733 {
2734 	int was_shielded = sshkey_is_shielded(key);
2735 	int r2, r = SSH_ERR_INTERNAL_ERROR;
2736 
2737 	if (sigp != NULL)
2738 		*sigp = NULL;
2739 	if (lenp != NULL)
2740 		*lenp = 0;
2741 	if (datalen > SSH_KEY_MAX_SIGN_DATA_SIZE)
2742 		return SSH_ERR_INVALID_ARGUMENT;
2743 	if ((r = sshkey_unshield_private(key)) != 0)
2744 		return r;
2745 	switch (key->type) {
2746 #ifdef WITH_OPENSSL
2747 	case KEY_DSA_CERT:
2748 	case KEY_DSA:
2749 		r = ssh_dss_sign(key, sigp, lenp, data, datalen, compat);
2750 		break;
2751 # ifdef OPENSSL_HAS_ECC
2752 	case KEY_ECDSA_CERT:
2753 	case KEY_ECDSA:
2754 		r = ssh_ecdsa_sign(key, sigp, lenp, data, datalen, compat);
2755 		break;
2756 # endif /* OPENSSL_HAS_ECC */
2757 	case KEY_RSA_CERT:
2758 	case KEY_RSA:
2759 		r = ssh_rsa_sign(key, sigp, lenp, data, datalen, alg);
2760 		break;
2761 #endif /* WITH_OPENSSL */
2762 	case KEY_ED25519:
2763 	case KEY_ED25519_CERT:
2764 		r = ssh_ed25519_sign(key, sigp, lenp, data, datalen, compat);
2765 		break;
2766 	case KEY_ED25519_SK:
2767 	case KEY_ED25519_SK_CERT:
2768 	case KEY_ECDSA_SK_CERT:
2769 	case KEY_ECDSA_SK:
2770 		r = sshsk_sign(sk_provider, key, sigp, lenp, data,
2771 		    datalen, compat, /* XXX PIN */ NULL);
2772 		break;
2773 #ifdef WITH_XMSS
2774 	case KEY_XMSS:
2775 	case KEY_XMSS_CERT:
2776 		r = ssh_xmss_sign(key, sigp, lenp, data, datalen, compat);
2777 		break;
2778 #endif /* WITH_XMSS */
2779 	default:
2780 		r = SSH_ERR_KEY_TYPE_UNKNOWN;
2781 		break;
2782 	}
2783 	if (was_shielded && (r2 = sshkey_shield_private(key)) != 0)
2784 		return r2;
2785 	return r;
2786 }
2787 
2788 /*
2789  * ssh_key_verify returns 0 for a correct signature  and < 0 on error.
2790  * If "alg" specified, then the signature must use that algorithm.
2791  */
2792 int
2793 sshkey_verify(const struct sshkey *key,
2794     const u_char *sig, size_t siglen,
2795     const u_char *data, size_t dlen, const char *alg, u_int compat,
2796     struct sshkey_sig_details **detailsp)
2797 {
2798 	if (detailsp != NULL)
2799 		*detailsp = NULL;
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 	case KEY_ECDSA_SK_CERT:
2812 	case KEY_ECDSA_SK:
2813 		return ssh_ecdsa_sk_verify(key, sig, siglen, data, dlen,
2814 		    compat, detailsp);
2815 # endif /* OPENSSL_HAS_ECC */
2816 	case KEY_RSA_CERT:
2817 	case KEY_RSA:
2818 		return ssh_rsa_verify(key, sig, siglen, data, dlen, alg);
2819 #endif /* WITH_OPENSSL */
2820 	case KEY_ED25519:
2821 	case KEY_ED25519_CERT:
2822 		return ssh_ed25519_verify(key, sig, siglen, data, dlen, compat);
2823 	case KEY_ED25519_SK:
2824 	case KEY_ED25519_SK_CERT:
2825 		return ssh_ed25519_sk_verify(key, sig, siglen, data, dlen,
2826 		    compat, detailsp);
2827 #ifdef WITH_XMSS
2828 	case KEY_XMSS:
2829 	case KEY_XMSS_CERT:
2830 		return ssh_xmss_verify(key, sig, siglen, data, dlen, compat);
2831 #endif /* WITH_XMSS */
2832 	default:
2833 		return SSH_ERR_KEY_TYPE_UNKNOWN;
2834 	}
2835 }
2836 
2837 /* Convert a plain key to their _CERT equivalent */
2838 int
2839 sshkey_to_certified(struct sshkey *k)
2840 {
2841 	int newtype;
2842 
2843 	switch (k->type) {
2844 #ifdef WITH_OPENSSL
2845 	case KEY_RSA:
2846 		newtype = KEY_RSA_CERT;
2847 		break;
2848 	case KEY_DSA:
2849 		newtype = KEY_DSA_CERT;
2850 		break;
2851 	case KEY_ECDSA:
2852 		newtype = KEY_ECDSA_CERT;
2853 		break;
2854 	case KEY_ECDSA_SK:
2855 		newtype = KEY_ECDSA_SK_CERT;
2856 		break;
2857 #endif /* WITH_OPENSSL */
2858 	case KEY_ED25519_SK:
2859 		newtype = KEY_ED25519_SK_CERT;
2860 		break;
2861 	case KEY_ED25519:
2862 		newtype = KEY_ED25519_CERT;
2863 		break;
2864 #ifdef WITH_XMSS
2865 	case KEY_XMSS:
2866 		newtype = KEY_XMSS_CERT;
2867 		break;
2868 #endif /* WITH_XMSS */
2869 	default:
2870 		return SSH_ERR_INVALID_ARGUMENT;
2871 	}
2872 	if ((k->cert = cert_new()) == NULL)
2873 		return SSH_ERR_ALLOC_FAIL;
2874 	k->type = newtype;
2875 	return 0;
2876 }
2877 
2878 /* Convert a certificate to its raw key equivalent */
2879 int
2880 sshkey_drop_cert(struct sshkey *k)
2881 {
2882 	if (!sshkey_type_is_cert(k->type))
2883 		return SSH_ERR_KEY_TYPE_UNKNOWN;
2884 	cert_free(k->cert);
2885 	k->cert = NULL;
2886 	k->type = sshkey_type_plain(k->type);
2887 	return 0;
2888 }
2889 
2890 /* Sign a certified key, (re-)generating the signed certblob. */
2891 int
2892 sshkey_certify_custom(struct sshkey *k, struct sshkey *ca, const char *alg,
2893     const char *sk_provider, sshkey_certify_signer *signer, void *signer_ctx)
2894 {
2895 	struct sshbuf *principals = NULL;
2896 	u_char *ca_blob = NULL, *sig_blob = NULL, nonce[32];
2897 	size_t i, ca_len, sig_len;
2898 	int ret = SSH_ERR_INTERNAL_ERROR;
2899 	struct sshbuf *cert = NULL;
2900 	char *sigtype = NULL;
2901 #ifdef WITH_OPENSSL
2902 	const BIGNUM *rsa_n, *rsa_e, *dsa_p, *dsa_q, *dsa_g, *dsa_pub_key;
2903 #endif /* WITH_OPENSSL */
2904 
2905 	if (k == NULL || k->cert == NULL ||
2906 	    k->cert->certblob == NULL || ca == NULL)
2907 		return SSH_ERR_INVALID_ARGUMENT;
2908 	if (!sshkey_is_cert(k))
2909 		return SSH_ERR_KEY_TYPE_UNKNOWN;
2910 	if (!sshkey_type_is_valid_ca(ca->type))
2911 		return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
2912 
2913 	/*
2914 	 * If no alg specified as argument but a signature_type was set,
2915 	 * then prefer that. If both were specified, then they must match.
2916 	 */
2917 	if (alg == NULL)
2918 		alg = k->cert->signature_type;
2919 	else if (k->cert->signature_type != NULL &&
2920 	    strcmp(alg, k->cert->signature_type) != 0)
2921 		return SSH_ERR_INVALID_ARGUMENT;
2922 
2923 	/*
2924 	 * If no signing algorithm or signature_type was specified and we're
2925 	 * using a RSA key, then default to a good signature algorithm.
2926 	 */
2927 	if (alg == NULL && ca->type == KEY_RSA)
2928 		alg = "rsa-sha2-512";
2929 
2930 	if ((ret = sshkey_to_blob(ca, &ca_blob, &ca_len)) != 0)
2931 		return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
2932 
2933 	cert = k->cert->certblob; /* for readability */
2934 	sshbuf_reset(cert);
2935 	if ((ret = sshbuf_put_cstring(cert, sshkey_ssh_name(k))) != 0)
2936 		goto out;
2937 
2938 	/* -v01 certs put nonce first */
2939 	arc4random_buf(&nonce, sizeof(nonce));
2940 	if ((ret = sshbuf_put_string(cert, nonce, sizeof(nonce))) != 0)
2941 		goto out;
2942 
2943 	/* XXX this substantially duplicates to_blob(); refactor */
2944 	switch (k->type) {
2945 #ifdef WITH_OPENSSL
2946 	case KEY_DSA_CERT:
2947 		DSA_get0_pqg(k->dsa, &dsa_p, &dsa_q, &dsa_g);
2948 		DSA_get0_key(k->dsa, &dsa_pub_key, NULL);
2949 		if ((ret = sshbuf_put_bignum2(cert, dsa_p)) != 0 ||
2950 		    (ret = sshbuf_put_bignum2(cert, dsa_q)) != 0 ||
2951 		    (ret = sshbuf_put_bignum2(cert, dsa_g)) != 0 ||
2952 		    (ret = sshbuf_put_bignum2(cert, dsa_pub_key)) != 0)
2953 			goto out;
2954 		break;
2955 # ifdef OPENSSL_HAS_ECC
2956 	case KEY_ECDSA_CERT:
2957 	case KEY_ECDSA_SK_CERT:
2958 		if ((ret = sshbuf_put_cstring(cert,
2959 		    sshkey_curve_nid_to_name(k->ecdsa_nid))) != 0 ||
2960 		    (ret = sshbuf_put_ec(cert,
2961 		    EC_KEY_get0_public_key(k->ecdsa),
2962 		    EC_KEY_get0_group(k->ecdsa))) != 0)
2963 			goto out;
2964 		if (k->type == KEY_ECDSA_SK_CERT) {
2965 			if ((ret = sshbuf_put_cstring(cert,
2966 			    k->sk_application)) != 0)
2967 				goto out;
2968 		}
2969 		break;
2970 # endif /* OPENSSL_HAS_ECC */
2971 	case KEY_RSA_CERT:
2972 		RSA_get0_key(k->rsa, &rsa_n, &rsa_e, NULL);
2973 		if ((ret = sshbuf_put_bignum2(cert, rsa_e)) != 0 ||
2974 		    (ret = sshbuf_put_bignum2(cert, rsa_n)) != 0)
2975 			goto out;
2976 		break;
2977 #endif /* WITH_OPENSSL */
2978 	case KEY_ED25519_CERT:
2979 	case KEY_ED25519_SK_CERT:
2980 		if ((ret = sshbuf_put_string(cert,
2981 		    k->ed25519_pk, ED25519_PK_SZ)) != 0)
2982 			goto out;
2983 		if (k->type == KEY_ED25519_SK_CERT) {
2984 			if ((ret = sshbuf_put_cstring(cert,
2985 			    k->sk_application)) != 0)
2986 				goto out;
2987 		}
2988 		break;
2989 #ifdef WITH_XMSS
2990 	case KEY_XMSS_CERT:
2991 		if (k->xmss_name == NULL) {
2992 			ret = SSH_ERR_INVALID_ARGUMENT;
2993 			goto out;
2994 		}
2995 		if ((ret = sshbuf_put_cstring(cert, k->xmss_name)) ||
2996 		    (ret = sshbuf_put_string(cert,
2997 		    k->xmss_pk, sshkey_xmss_pklen(k))) != 0)
2998 			goto out;
2999 		break;
3000 #endif /* WITH_XMSS */
3001 	default:
3002 		ret = SSH_ERR_INVALID_ARGUMENT;
3003 		goto out;
3004 	}
3005 
3006 	if ((ret = sshbuf_put_u64(cert, k->cert->serial)) != 0 ||
3007 	    (ret = sshbuf_put_u32(cert, k->cert->type)) != 0 ||
3008 	    (ret = sshbuf_put_cstring(cert, k->cert->key_id)) != 0)
3009 		goto out;
3010 
3011 	if ((principals = sshbuf_new()) == NULL) {
3012 		ret = SSH_ERR_ALLOC_FAIL;
3013 		goto out;
3014 	}
3015 	for (i = 0; i < k->cert->nprincipals; i++) {
3016 		if ((ret = sshbuf_put_cstring(principals,
3017 		    k->cert->principals[i])) != 0)
3018 			goto out;
3019 	}
3020 	if ((ret = sshbuf_put_stringb(cert, principals)) != 0 ||
3021 	    (ret = sshbuf_put_u64(cert, k->cert->valid_after)) != 0 ||
3022 	    (ret = sshbuf_put_u64(cert, k->cert->valid_before)) != 0 ||
3023 	    (ret = sshbuf_put_stringb(cert, k->cert->critical)) != 0 ||
3024 	    (ret = sshbuf_put_stringb(cert, k->cert->extensions)) != 0 ||
3025 	    (ret = sshbuf_put_string(cert, NULL, 0)) != 0 || /* Reserved */
3026 	    (ret = sshbuf_put_string(cert, ca_blob, ca_len)) != 0)
3027 		goto out;
3028 
3029 	/* Sign the whole mess */
3030 	if ((ret = signer(ca, &sig_blob, &sig_len, sshbuf_ptr(cert),
3031 	    sshbuf_len(cert), alg, sk_provider, 0, signer_ctx)) != 0)
3032 		goto out;
3033 	/* Check and update signature_type against what was actually used */