xref: /openbsd-src/lib/libssl/ssl_cert.c (revision f84b1df5a16cdd762c93854218de246e79975d3b)
1 /* $OpenBSD: ssl_cert.c,v 1.95 2022/02/05 14:54:10 jsing Exp $ */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3  * All rights reserved.
4  *
5  * This package is an SSL implementation written
6  * by Eric Young (eay@cryptsoft.com).
7  * The implementation was written so as to conform with Netscapes SSL.
8  *
9  * This library is free for commercial and non-commercial use as long as
10  * the following conditions are aheared to.  The following conditions
11  * apply to all code found in this distribution, be it the RC4, RSA,
12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13  * included with this distribution is covered by the same copyright terms
14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15  *
16  * Copyright remains Eric Young's, and as such any Copyright notices in
17  * the code are not to be removed.
18  * If this package is used in a product, Eric Young should be given attribution
19  * as the author of the parts of the library used.
20  * This can be in the form of a textual message at program startup or
21  * in documentation (online or textual) provided with the package.
22  *
23  * Redistribution and use in source and binary forms, with or without
24  * modification, are permitted provided that the following conditions
25  * are met:
26  * 1. Redistributions of source code must retain the copyright
27  *    notice, this list of conditions and the following disclaimer.
28  * 2. Redistributions in binary form must reproduce the above copyright
29  *    notice, this list of conditions and the following disclaimer in the
30  *    documentation and/or other materials provided with the distribution.
31  * 3. All advertising materials mentioning features or use of this software
32  *    must display the following acknowledgement:
33  *    "This product includes cryptographic software written by
34  *     Eric Young (eay@cryptsoft.com)"
35  *    The word 'cryptographic' can be left out if the rouines from the library
36  *    being used are not cryptographic related :-).
37  * 4. If you include any Windows specific code (or a derivative thereof) from
38  *    the apps directory (application code) you must include an acknowledgement:
39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40  *
41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51  * SUCH DAMAGE.
52  *
53  * The licence and distribution terms for any publically available version or
54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
55  * copied and put under another distribution licence
56  * [including the GNU Public Licence.]
57  */
58 /* ====================================================================
59  * Copyright (c) 1998-2007 The OpenSSL Project.  All rights reserved.
60  *
61  * Redistribution and use in source and binary forms, with or without
62  * modification, are permitted provided that the following conditions
63  * are met:
64  *
65  * 1. Redistributions of source code must retain the above copyright
66  *    notice, this list of conditions and the following disclaimer.
67  *
68  * 2. Redistributions in binary form must reproduce the above copyright
69  *    notice, this list of conditions and the following disclaimer in
70  *    the documentation and/or other materials provided with the
71  *    distribution.
72  *
73  * 3. All advertising materials mentioning features or use of this
74  *    software must display the following acknowledgment:
75  *    "This product includes software developed by the OpenSSL Project
76  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
77  *
78  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
79  *    endorse or promote products derived from this software without
80  *    prior written permission. For written permission, please contact
81  *    openssl-core@openssl.org.
82  *
83  * 5. Products derived from this software may not be called "OpenSSL"
84  *    nor may "OpenSSL" appear in their names without prior written
85  *    permission of the OpenSSL Project.
86  *
87  * 6. Redistributions of any form whatsoever must retain the following
88  *    acknowledgment:
89  *    "This product includes software developed by the OpenSSL Project
90  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
91  *
92  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
93  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
94  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
95  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
96  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
97  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
98  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
99  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
100  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
101  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
102  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
103  * OF THE POSSIBILITY OF SUCH DAMAGE.
104  * ====================================================================
105  *
106  * This product includes cryptographic software written by Eric Young
107  * (eay@cryptsoft.com).  This product includes software written by Tim
108  * Hudson (tjh@cryptsoft.com).
109  *
110  */
111 /* ====================================================================
112  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
113  * ECC cipher suite support in OpenSSL originally developed by
114  * SUN MICROSYSTEMS, INC., and contributed to the OpenSSL project.
115  */
116 
117 #include <sys/types.h>
118 
119 #include <dirent.h>
120 #include <stdio.h>
121 #include <unistd.h>
122 
123 #include <openssl/bio.h>
124 #include <openssl/bn.h>
125 #include <openssl/dh.h>
126 #include <openssl/objects.h>
127 #include <openssl/opensslconf.h>
128 #include <openssl/pem.h>
129 #include <openssl/x509v3.h>
130 
131 #include "ssl_locl.h"
132 
133 int
134 SSL_get_ex_data_X509_STORE_CTX_idx(void)
135 {
136 	static volatile int ssl_x509_store_ctx_idx = -1;
137 	int got_write_lock = 0;
138 
139 	CRYPTO_r_lock(CRYPTO_LOCK_SSL_CTX);
140 
141 	if (ssl_x509_store_ctx_idx < 0) {
142 		CRYPTO_r_unlock(CRYPTO_LOCK_SSL_CTX);
143 		CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
144 		got_write_lock = 1;
145 
146 		if (ssl_x509_store_ctx_idx < 0) {
147 			ssl_x509_store_ctx_idx =
148 			    X509_STORE_CTX_get_ex_new_index(
149 				0, "SSL for verify callback", NULL, NULL, NULL);
150 		}
151 	}
152 
153 	if (got_write_lock)
154 		CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
155 	else
156 		CRYPTO_r_unlock(CRYPTO_LOCK_SSL_CTX);
157 
158 	return ssl_x509_store_ctx_idx;
159 }
160 
161 SSL_CERT *
162 ssl_cert_new(void)
163 {
164 	SSL_CERT *ret;
165 
166 	ret = calloc(1, sizeof(SSL_CERT));
167 	if (ret == NULL) {
168 		SSLerrorx(ERR_R_MALLOC_FAILURE);
169 		return (NULL);
170 	}
171 	ret->key = &(ret->pkeys[SSL_PKEY_RSA]);
172 	ret->references = 1;
173 	return (ret);
174 }
175 
176 SSL_CERT *
177 ssl_cert_dup(SSL_CERT *cert)
178 {
179 	SSL_CERT *ret;
180 	int i;
181 
182 	ret = calloc(1, sizeof(SSL_CERT));
183 	if (ret == NULL) {
184 		SSLerrorx(ERR_R_MALLOC_FAILURE);
185 		return (NULL);
186 	}
187 
188 	/*
189 	 * same as ret->key = ret->pkeys + (cert->key - cert->pkeys),
190 	 * if you find that more readable
191 	 */
192 	ret->key = &ret->pkeys[cert->key - &cert->pkeys[0]];
193 
194 	ret->valid = cert->valid;
195 	ret->mask_k = cert->mask_k;
196 	ret->mask_a = cert->mask_a;
197 
198 	if (cert->dhe_params != NULL) {
199 		ret->dhe_params = DHparams_dup(cert->dhe_params);
200 		if (ret->dhe_params == NULL) {
201 			SSLerrorx(ERR_R_DH_LIB);
202 			goto err;
203 		}
204 	}
205 	ret->dhe_params_cb = cert->dhe_params_cb;
206 	ret->dhe_params_auto = cert->dhe_params_auto;
207 
208 	for (i = 0; i < SSL_PKEY_NUM; i++) {
209 		if (cert->pkeys[i].x509 != NULL) {
210 			ret->pkeys[i].x509 = cert->pkeys[i].x509;
211 			X509_up_ref(ret->pkeys[i].x509);
212 		}
213 
214 		if (cert->pkeys[i].privatekey != NULL) {
215 			ret->pkeys[i].privatekey = cert->pkeys[i].privatekey;
216 			EVP_PKEY_up_ref(ret->pkeys[i].privatekey);
217 			switch (i) {
218 				/*
219 				 * If there was anything special to do for
220 				 * certain types of keys, we'd do it here.
221 				 * (Nothing at the moment, I think.)
222 				 */
223 
224 			case SSL_PKEY_RSA:
225 				/* We have an RSA key. */
226 				break;
227 
228 			case SSL_PKEY_ECC:
229 				/* We have an ECC key */
230 				break;
231 
232 			case SSL_PKEY_GOST01:
233 				/* We have a GOST key */
234 				break;
235 
236 			default:
237 				/* Can't happen. */
238 				SSLerrorx(SSL_R_LIBRARY_BUG);
239 			}
240 		}
241 
242 		if (cert->pkeys[i].chain != NULL) {
243 			if ((ret->pkeys[i].chain =
244 			    X509_chain_up_ref(cert->pkeys[i].chain)) == NULL)
245 				goto err;
246 		}
247 	}
248 
249 	/*
250 	 * ret->extra_certs *should* exist, but currently the own certificate
251 	 * chain is held inside SSL_CTX
252 	 */
253 
254 	ret->references = 1;
255 
256 	return (ret);
257 
258  err:
259 	DH_free(ret->dhe_params);
260 
261 	for (i = 0; i < SSL_PKEY_NUM; i++) {
262 		X509_free(ret->pkeys[i].x509);
263 		EVP_PKEY_free(ret->pkeys[i].privatekey);
264 		sk_X509_pop_free(ret->pkeys[i].chain, X509_free);
265 	}
266 	free (ret);
267 	return NULL;
268 }
269 
270 
271 void
272 ssl_cert_free(SSL_CERT *c)
273 {
274 	int i;
275 
276 	if (c == NULL)
277 		return;
278 
279 	i = CRYPTO_add(&c->references, -1, CRYPTO_LOCK_SSL_CERT);
280 	if (i > 0)
281 		return;
282 
283 	DH_free(c->dhe_params);
284 
285 	for (i = 0; i < SSL_PKEY_NUM; i++) {
286 		X509_free(c->pkeys[i].x509);
287 		EVP_PKEY_free(c->pkeys[i].privatekey);
288 		sk_X509_pop_free(c->pkeys[i].chain, X509_free);
289 	}
290 
291 	free(c);
292 }
293 
294 int
295 ssl_cert_set0_chain(SSL_CERT *c, STACK_OF(X509) *chain)
296 {
297 	if (c->key == NULL)
298 		return 0;
299 
300 	sk_X509_pop_free(c->key->chain, X509_free);
301 	c->key->chain = chain;
302 
303 	return 1;
304 }
305 
306 int
307 ssl_cert_set1_chain(SSL_CERT *c, STACK_OF(X509) *chain)
308 {
309 	STACK_OF(X509) *new_chain = NULL;
310 
311 	if (chain != NULL) {
312 		if ((new_chain = X509_chain_up_ref(chain)) == NULL)
313 			return 0;
314 	}
315 	if (!ssl_cert_set0_chain(c, new_chain)) {
316 		sk_X509_pop_free(new_chain, X509_free);
317 		return 0;
318 	}
319 
320 	return 1;
321 }
322 
323 int
324 ssl_cert_add0_chain_cert(SSL_CERT *c, X509 *cert)
325 {
326 	if (c->key == NULL)
327 		return 0;
328 
329 	if (c->key->chain == NULL) {
330 		if ((c->key->chain = sk_X509_new_null()) == NULL)
331 			return 0;
332 	}
333 	if (!sk_X509_push(c->key->chain, cert))
334 		return 0;
335 
336 	return 1;
337 }
338 
339 int
340 ssl_cert_add1_chain_cert(SSL_CERT *c, X509 *cert)
341 {
342 	if (!ssl_cert_add0_chain_cert(c, cert))
343 		return 0;
344 
345 	X509_up_ref(cert);
346 
347 	return 1;
348 }
349 
350 int
351 ssl_verify_cert_chain(SSL *s, STACK_OF(X509) *sk)
352 {
353 	X509_STORE_CTX *ctx = NULL;
354 	X509 *x;
355 	int ret = 0;
356 
357 	if ((sk == NULL) || (sk_X509_num(sk) == 0))
358 		goto err;
359 
360 	if ((ctx = X509_STORE_CTX_new()) == NULL)
361 		goto err;
362 
363 	x = sk_X509_value(sk, 0);
364 	if (!X509_STORE_CTX_init(ctx, s->ctx->cert_store, x, sk)) {
365 		SSLerror(s, ERR_R_X509_LIB);
366 		goto err;
367 	}
368 	X509_STORE_CTX_set_ex_data(ctx, SSL_get_ex_data_X509_STORE_CTX_idx(), s);
369 
370 	/*
371 	 * We need to inherit the verify parameters. These can be
372 	 * determined by the context: if its a server it will verify
373 	 * SSL client certificates or vice versa.
374 	 */
375 	X509_STORE_CTX_set_default(ctx, s->server ? "ssl_client" : "ssl_server");
376 
377 	/*
378 	 * Anything non-default in "param" should overwrite anything
379 	 * in the ctx.
380 	 */
381 	X509_VERIFY_PARAM_set1(X509_STORE_CTX_get0_param(ctx), s->param);
382 
383 	if (s->internal->verify_callback)
384 		X509_STORE_CTX_set_verify_cb(ctx, s->internal->verify_callback);
385 
386 	if (s->ctx->internal->app_verify_callback != NULL)
387 		ret = s->ctx->internal->app_verify_callback(ctx,
388 		    s->ctx->internal->app_verify_arg);
389 	else
390 		ret = X509_verify_cert(ctx);
391 
392 	s->verify_result = X509_STORE_CTX_get_error(ctx);
393 	sk_X509_pop_free(s->internal->verified_chain, X509_free);
394 	s->internal->verified_chain = NULL;
395 	if (X509_STORE_CTX_get0_chain(ctx) != NULL) {
396 		s->internal->verified_chain = X509_STORE_CTX_get1_chain(ctx);
397 		if (s->internal->verified_chain == NULL) {
398 			SSLerrorx(ERR_R_MALLOC_FAILURE);
399 			ret = 0;
400 		}
401 	}
402 
403  err:
404 	X509_STORE_CTX_free(ctx);
405 
406 	return (ret);
407 }
408 
409 static void
410 set_client_CA_list(STACK_OF(X509_NAME) **ca_list,
411     STACK_OF(X509_NAME) *name_list)
412 {
413 	sk_X509_NAME_pop_free(*ca_list, X509_NAME_free);
414 	*ca_list = name_list;
415 }
416 
417 STACK_OF(X509_NAME) *
418 SSL_dup_CA_list(const STACK_OF(X509_NAME) *sk)
419 {
420 	int i;
421 	STACK_OF(X509_NAME) *ret;
422 	X509_NAME *name = NULL;
423 
424 	if ((ret = sk_X509_NAME_new_null()) == NULL)
425 		goto err;
426 
427 	for (i = 0; i < sk_X509_NAME_num(sk); i++) {
428 		if ((name = X509_NAME_dup(sk_X509_NAME_value(sk, i))) == NULL)
429 			goto err;
430 		if (!sk_X509_NAME_push(ret, name))
431 			goto err;
432 	}
433 	return (ret);
434 
435  err:
436 	X509_NAME_free(name);
437 	sk_X509_NAME_pop_free(ret, X509_NAME_free);
438 	return NULL;
439 }
440 
441 void
442 SSL_set_client_CA_list(SSL *s, STACK_OF(X509_NAME) *name_list)
443 {
444 	set_client_CA_list(&(s->internal->client_CA), name_list);
445 }
446 
447 void
448 SSL_CTX_set_client_CA_list(SSL_CTX *ctx, STACK_OF(X509_NAME) *name_list)
449 {
450 	set_client_CA_list(&(ctx->internal->client_CA), name_list);
451 }
452 
453 STACK_OF(X509_NAME) *
454 SSL_CTX_get_client_CA_list(const SSL_CTX *ctx)
455 {
456 	return (ctx->internal->client_CA);
457 }
458 
459 STACK_OF(X509_NAME) *
460 SSL_get_client_CA_list(const SSL *s)
461 {
462 	if (!s->server) {
463 		/* We are in the client. */
464 		if ((s->version >> 8) == SSL3_VERSION_MAJOR)
465 			return (s->s3->hs.tls12.ca_names);
466 		else
467 			return (NULL);
468 	} else {
469 		if (s->internal->client_CA != NULL)
470 			return (s->internal->client_CA);
471 		else
472 			return (s->ctx->internal->client_CA);
473 	}
474 }
475 
476 static int
477 add_client_CA(STACK_OF(X509_NAME) **sk, X509 *x)
478 {
479 	X509_NAME *name;
480 
481 	if (x == NULL)
482 		return (0);
483 	if ((*sk == NULL) && ((*sk = sk_X509_NAME_new_null()) == NULL))
484 		return (0);
485 
486 	if ((name = X509_NAME_dup(X509_get_subject_name(x))) == NULL)
487 		return (0);
488 
489 	if (!sk_X509_NAME_push(*sk, name)) {
490 		X509_NAME_free(name);
491 		return (0);
492 	}
493 	return (1);
494 }
495 
496 int
497 SSL_add_client_CA(SSL *ssl, X509 *x)
498 {
499 	return (add_client_CA(&(ssl->internal->client_CA), x));
500 }
501 
502 int
503 SSL_CTX_add_client_CA(SSL_CTX *ctx, X509 *x)
504 {
505 	return (add_client_CA(&(ctx->internal->client_CA), x));
506 }
507 
508 static int
509 xname_cmp(const X509_NAME * const *a, const X509_NAME * const *b)
510 {
511 	return (X509_NAME_cmp(*a, *b));
512 }
513 
514 /*!
515  * Load CA certs from a file into a ::STACK. Note that it is somewhat misnamed;
516  * it doesn't really have anything to do with clients (except that a common use
517  * for a stack of CAs is to send it to the client). Actually, it doesn't have
518  * much to do with CAs, either, since it will load any old cert.
519  * \param file the file containing one or more certs.
520  * \return a ::STACK containing the certs.
521  */
522 STACK_OF(X509_NAME) *
523 SSL_load_client_CA_file(const char *file)
524 {
525 	BIO *in;
526 	X509 *x = NULL;
527 	X509_NAME *xn = NULL;
528 	STACK_OF(X509_NAME) *ret = NULL, *sk;
529 
530 	sk = sk_X509_NAME_new(xname_cmp);
531 
532 	in = BIO_new(BIO_s_file());
533 
534 	if ((sk == NULL) || (in == NULL)) {
535 		SSLerrorx(ERR_R_MALLOC_FAILURE);
536 		goto err;
537 	}
538 
539 	if (!BIO_read_filename(in, file))
540 		goto err;
541 
542 	for (;;) {
543 		if (PEM_read_bio_X509(in, &x, NULL, NULL) == NULL)
544 			break;
545 		if (ret == NULL) {
546 			ret = sk_X509_NAME_new_null();
547 			if (ret == NULL) {
548 				SSLerrorx(ERR_R_MALLOC_FAILURE);
549 				goto err;
550 			}
551 		}
552 		if ((xn = X509_get_subject_name(x)) == NULL)
553 			goto err;
554 		/* check for duplicates */
555 		xn = X509_NAME_dup(xn);
556 		if (xn == NULL)
557 			goto err;
558 		if (sk_X509_NAME_find(sk, xn) >= 0)
559 			X509_NAME_free(xn);
560 		else {
561 			if (!sk_X509_NAME_push(sk, xn))
562 				goto err;
563 			if (!sk_X509_NAME_push(ret, xn))
564 				goto err;
565 		}
566 	}
567 
568 	if (0) {
569  err:
570 		sk_X509_NAME_pop_free(ret, X509_NAME_free);
571 		ret = NULL;
572 	}
573 	sk_X509_NAME_free(sk);
574 	BIO_free(in);
575 	X509_free(x);
576 	if (ret != NULL)
577 		ERR_clear_error();
578 
579 	return (ret);
580 }
581 
582 /*!
583  * Add a file of certs to a stack.
584  * \param stack the stack to add to.
585  * \param file the file to add from. All certs in this file that are not
586  * already in the stack will be added.
587  * \return 1 for success, 0 for failure. Note that in the case of failure some
588  * certs may have been added to \c stack.
589  */
590 
591 int
592 SSL_add_file_cert_subjects_to_stack(STACK_OF(X509_NAME) *stack,
593     const char *file)
594 {
595 	BIO *in;
596 	X509 *x = NULL;
597 	X509_NAME *xn = NULL;
598 	int ret = 1;
599 	int (*oldcmp)(const X509_NAME * const *a, const X509_NAME * const *b);
600 
601 	oldcmp = sk_X509_NAME_set_cmp_func(stack, xname_cmp);
602 
603 	in = BIO_new(BIO_s_file());
604 
605 	if (in == NULL) {
606 		SSLerrorx(ERR_R_MALLOC_FAILURE);
607 		goto err;
608 	}
609 
610 	if (!BIO_read_filename(in, file))
611 		goto err;
612 
613 	for (;;) {
614 		if (PEM_read_bio_X509(in, &x, NULL, NULL) == NULL)
615 			break;
616 		if ((xn = X509_get_subject_name(x)) == NULL)
617 			goto err;
618 		xn = X509_NAME_dup(xn);
619 		if (xn == NULL)
620 			goto err;
621 		if (sk_X509_NAME_find(stack, xn) >= 0)
622 			X509_NAME_free(xn);
623 		else
624 			if (!sk_X509_NAME_push(stack, xn))
625 				goto err;
626 	}
627 
628 	ERR_clear_error();
629 
630 	if (0) {
631  err:
632 		ret = 0;
633 	}
634 	BIO_free(in);
635 	X509_free(x);
636 
637 	(void)sk_X509_NAME_set_cmp_func(stack, oldcmp);
638 
639 	return ret;
640 }
641 
642 /*!
643  * Add a directory of certs to a stack.
644  * \param stack the stack to append to.
645  * \param dir the directory to append from. All files in this directory will be
646  * examined as potential certs. Any that are acceptable to
647  * SSL_add_dir_cert_subjects_to_stack() that are not already in the stack will
648  * be included.
649  * \return 1 for success, 0 for failure. Note that in the case of failure some
650  * certs may have been added to \c stack.
651  */
652 
653 int
654 SSL_add_dir_cert_subjects_to_stack(STACK_OF(X509_NAME) *stack, const char *dir)
655 {
656 	DIR *dirp = NULL;
657 	char *path = NULL;
658 	int ret = 0;
659 
660 	dirp = opendir(dir);
661 	if (dirp) {
662 		struct dirent *dp;
663 		while ((dp = readdir(dirp)) != NULL) {
664 			if (asprintf(&path, "%s/%s", dir, dp->d_name) != -1) {
665 				ret = SSL_add_file_cert_subjects_to_stack(
666 				    stack, path);
667 				free(path);
668 			}
669 			if (!ret)
670 				break;
671 		}
672 		(void) closedir(dirp);
673 	}
674 	if (!ret) {
675  		SYSerror(errno);
676 		ERR_asprintf_error_data("opendir ('%s')", dir);
677 		SSLerrorx(ERR_R_SYS_LIB);
678 	}
679 	return ret;
680 }
681