1 /* $OpenBSD: tls.c,v 1.97 2023/06/18 11:43:03 op Exp $ */
2 /*
3  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include "config.h"
19 
20 #include <sys/socket.h>
21 
22 #include <errno.h>
23 #include <limits.h>
24 #include <stdlib.h>
25 #include <string.h>
26 #include <unistd.h>
27 
28 #include <openssl/bio.h>
29 #include <openssl/err.h>
30 #include <openssl/evp.h>
31 #include <openssl/pem.h>
32 #include <openssl/safestack.h>
33 #include <openssl/ssl.h>
34 #include <openssl/x509.h>
35 
36 #include <tls.h>
37 #include "tls_internal.h"
38 
39 static struct tls_config *tls_config_default;
40 
41 static int tls_init_rv = -1;
42 
43 static void
44 tls_do_init(void)
45 {
46 	OPENSSL_init_ssl(OPENSSL_INIT_NO_LOAD_CONFIG, NULL);
47 
48 	if (BIO_sock_init() != 1)
49 		return;
50 
51 	if ((tls_config_default = tls_config_new_internal()) == NULL)
52 		return;
53 
54 	tls_config_default->refcount++;
55 
56 	tls_init_rv = 0;
57 }
58 
59 int
60 tls_init(void)
61 {
62 	if (tls_init_rv == -1)
63 		tls_do_init();
64 	return tls_init_rv;
65 }
66 
67 const char *
68 tls_error(struct tls *ctx)
69 {
70 	return ctx->error.msg;
71 }
72 
73 void
74 tls_error_clear(struct tls_error *error)
75 {
76 	free(error->msg);
77 	error->msg = NULL;
78 	error->num = 0;
79 	error->tls = 0;
80 }
81 
82 static int
83 tls_error_vset(struct tls_error *error, int errnum, const char *fmt, va_list ap)
84 {
85 	char *errmsg = NULL;
86 	int rv = -1;
87 
88 	tls_error_clear(error);
89 
90 	error->num = errnum;
91 	error->tls = 1;
92 
93 	if (vasprintf(&errmsg, fmt, ap) == -1) {
94 		errmsg = NULL;
95 		goto err;
96 	}
97 
98 	if (errnum == -1) {
99 		error->msg = errmsg;
100 		return (0);
101 	}
102 
103 	if (asprintf(&error->msg, "%s: %s", errmsg, strerror(errnum)) == -1) {
104 		error->msg = NULL;
105 		goto err;
106 	}
107 	rv = 0;
108 
109  err:
110 	free(errmsg);
111 
112 	return (rv);
113 }
114 
115 int
116 tls_error_set(struct tls_error *error, const char *fmt, ...)
117 {
118 	va_list ap;
119 	int errnum, rv;
120 
121 	errnum = errno;
122 
123 	va_start(ap, fmt);
124 	rv = tls_error_vset(error, errnum, fmt, ap);
125 	va_end(ap);
126 
127 	return (rv);
128 }
129 
130 int
131 tls_error_setx(struct tls_error *error, const char *fmt, ...)
132 {
133 	va_list ap;
134 	int rv;
135 
136 	va_start(ap, fmt);
137 	rv = tls_error_vset(error, -1, fmt, ap);
138 	va_end(ap);
139 
140 	return (rv);
141 }
142 
143 int
144 tls_config_set_error(struct tls_config *config, const char *fmt, ...)
145 {
146 	va_list ap;
147 	int errnum, rv;
148 
149 	errnum = errno;
150 
151 	va_start(ap, fmt);
152 	rv = tls_error_vset(&config->error, errnum, fmt, ap);
153 	va_end(ap);
154 
155 	return (rv);
156 }
157 
158 int
159 tls_config_set_errorx(struct tls_config *config, const char *fmt, ...)
160 {
161 	va_list ap;
162 	int rv;
163 
164 	va_start(ap, fmt);
165 	rv = tls_error_vset(&config->error, -1, fmt, ap);
166 	va_end(ap);
167 
168 	return (rv);
169 }
170 
171 int
172 tls_set_error(struct tls *ctx, const char *fmt, ...)
173 {
174 	va_list ap;
175 	int errnum, rv;
176 
177 	errnum = errno;
178 
179 	va_start(ap, fmt);
180 	rv = tls_error_vset(&ctx->error, errnum, fmt, ap);
181 	va_end(ap);
182 
183 	return (rv);
184 }
185 
186 int
187 tls_set_errorx(struct tls *ctx, const char *fmt, ...)
188 {
189 	va_list ap;
190 	int rv;
191 
192 	va_start(ap, fmt);
193 	rv = tls_error_vset(&ctx->error, -1, fmt, ap);
194 	va_end(ap);
195 
196 	return (rv);
197 }
198 
199 int
200 tls_set_ssl_errorx(struct tls *ctx, const char *fmt, ...)
201 {
202 	va_list ap;
203 	int rv;
204 
205 	/* Only set an error if a more specific one does not already exist. */
206 	if (ctx->error.tls != 0)
207 		return (0);
208 
209 	va_start(ap, fmt);
210 	rv = tls_error_vset(&ctx->error, -1, fmt, ap);
211 	va_end(ap);
212 
213 	return (rv);
214 }
215 
216 struct tls_sni_ctx *
217 tls_sni_ctx_new(void)
218 {
219 	return (calloc(1, sizeof(struct tls_sni_ctx)));
220 }
221 
222 void
223 tls_sni_ctx_free(struct tls_sni_ctx *sni_ctx)
224 {
225 	if (sni_ctx == NULL)
226 		return;
227 
228 	SSL_CTX_free(sni_ctx->ssl_ctx);
229 	X509_free(sni_ctx->ssl_cert);
230 
231 	free(sni_ctx);
232 }
233 
234 struct tls *
235 tls_new(void)
236 {
237 	struct tls *ctx;
238 
239 	if ((ctx = calloc(1, sizeof(*ctx))) == NULL)
240 		return (NULL);
241 
242 	tls_reset(ctx);
243 
244 	if (tls_configure(ctx, tls_config_default) == -1) {
245 		free(ctx);
246 		return NULL;
247 	}
248 
249 	return (ctx);
250 }
251 
252 int
253 tls_configure(struct tls *ctx, struct tls_config *config)
254 {
255 	if (config == NULL)
256 		config = tls_config_default;
257 
258 	config->refcount++;
259 
260 	tls_config_free(ctx->config);
261 
262 	ctx->config = config;
263 	ctx->keypair = config->keypair;
264 
265 	if ((ctx->flags & TLS_SERVER) != 0)
266 		return (tls_configure_server(ctx));
267 
268 	return (0);
269 }
270 
271 int
272 tls_cert_hash(X509 *cert, char **hash)
273 {
274 	char d[EVP_MAX_MD_SIZE], *dhex = NULL;
275 	int dlen, rv = -1;
276 
277 	free(*hash);
278 	*hash = NULL;
279 
280 	if (X509_digest(cert, EVP_sha256(), d, &dlen) != 1)
281 		goto err;
282 
283 	if (tls_hex_string(d, dlen, &dhex, NULL) != 0)
284 		goto err;
285 
286 	if (asprintf(hash, "SHA256:%s", dhex) == -1) {
287 		*hash = NULL;
288 		goto err;
289 	}
290 
291 	rv = 0;
292  err:
293 	free(dhex);
294 
295 	return (rv);
296 }
297 
298 int
299 tls_cert_pubkey_hash(X509 *cert, char **hash)
300 {
301 	char d[EVP_MAX_MD_SIZE], *dhex = NULL;
302 	int dlen, rv = -1;
303 
304 	free(*hash);
305 	*hash = NULL;
306 
307 	if (X509_pubkey_digest(cert, EVP_sha256(), d, &dlen) != 1)
308 		goto err;
309 
310 	if (tls_hex_string(d, dlen, &dhex, NULL) != 0)
311 		goto err;
312 
313 	if (asprintf(hash, "SHA256:%s", dhex) == -1) {
314 		*hash = NULL;
315 		goto err;
316 	}
317 
318 	rv = 0;
319 
320  err:
321 	free(dhex);
322 
323 	return (rv);
324 }
325 
326 static int
327 tls_keypair_to_pkey(struct tls *ctx, struct tls_keypair *keypair, EVP_PKEY **pkey)
328 {
329 	BIO *bio = NULL;
330 	X509 *x509 = NULL;
331 	char *mem;
332 	size_t len;
333 	int ret = -1;
334 
335 	*pkey = NULL;
336 
337 	if (ctx->config->use_fake_private_key) {
338 		mem = keypair->cert_mem;
339 		len = keypair->cert_len;
340 	} else {
341 		mem = keypair->key_mem;
342 		len = keypair->key_len;
343 	}
344 
345 	if (mem == NULL)
346 		return (0);
347 
348 	if (len > INT_MAX) {
349 		tls_set_errorx(ctx, ctx->config->use_fake_private_key ?
350 		    "cert too long" : "key too long");
351 		goto err;
352 	}
353 
354 	if ((bio = BIO_new_mem_buf(mem, len)) == NULL) {
355 		tls_set_errorx(ctx, "failed to create buffer");
356 		goto err;
357 	}
358 
359 	if (ctx->config->use_fake_private_key) {
360 		if ((x509 = PEM_read_bio_X509(bio, NULL, tls_password_cb,
361 		    NULL)) == NULL) {
362 			tls_set_errorx(ctx, "failed to read X509 certificate");
363 			goto err;
364 		}
365 		if ((*pkey = X509_get_pubkey(x509)) == NULL) {
366 			tls_set_errorx(ctx, "failed to retrieve pubkey");
367 			goto err;
368 		}
369 	} else {
370 		if ((*pkey = PEM_read_bio_PrivateKey(bio, NULL, tls_password_cb,
371 		    NULL)) ==  NULL) {
372 			tls_set_errorx(ctx, "failed to read private key");
373 			goto err;
374 		}
375 	}
376 
377 	ret = 0;
378  err:
379 	BIO_free(bio);
380 	X509_free(x509);
381 	return (ret);
382 }
383 
384 static int
385 tls_keypair_setup_pkey(struct tls *ctx, struct tls_keypair *keypair, EVP_PKEY *pkey)
386 {
387 	RSA *rsa = NULL;
388 	EC_KEY *eckey = NULL;
389 	int ret = -1;
390 
391 	/* Only install the pubkey hash if fake private keys are used. */
392 	if (!ctx->config->skip_private_key_check)
393 		return (0);
394 
395 	if (keypair->pubkey_hash == NULL) {
396 		tls_set_errorx(ctx, "public key hash not set");
397 		goto err;
398 	}
399 
400 	switch (EVP_PKEY_id(pkey)) {
401 	case EVP_PKEY_RSA:
402 		if ((rsa = EVP_PKEY_get1_RSA(pkey)) == NULL ||
403 		    RSA_set_ex_data(rsa, 0, keypair->pubkey_hash) == 0 ||
404 		    EVP_PKEY_set1_RSA(pkey, rsa) == 0) {
405 			tls_set_errorx(ctx, "RSA key setup failure");
406 			goto err;
407 		}
408 		break;
409 	case EVP_PKEY_EC:
410 		if ((eckey = EVP_PKEY_get1_EC_KEY(pkey)) == NULL ||
411 		    EC_KEY_set_ex_data(eckey, 0, keypair->pubkey_hash) == 0 ||
412 		    EVP_PKEY_set1_EC_KEY(pkey, eckey) == 0) {
413 			tls_set_errorx(ctx, "EC key setup failure");
414 			goto err;
415 		}
416 		break;
417 	default:
418 		tls_set_errorx(ctx, "incorrect key type");
419 		goto err;
420 	}
421 
422 	ret = 0;
423 
424  err:
425 	RSA_free(rsa);
426 	EC_KEY_free(eckey);
427 	return (ret);
428 }
429 
430 int
431 tls_configure_ssl_keypair(struct tls *ctx, SSL_CTX *ssl_ctx,
432     struct tls_keypair *keypair, int required)
433 {
434 	EVP_PKEY *pkey = NULL;
435 
436 	if (!required &&
437 	    keypair->cert_mem == NULL &&
438 	    keypair->key_mem == NULL)
439 		return(0);
440 
441 	if (keypair->cert_mem != NULL) {
442 		if (keypair->cert_len > INT_MAX) {
443 			tls_set_errorx(ctx, "certificate too long");
444 			goto err;
445 		}
446 
447 		if (SSL_CTX_use_certificate_chain_mem(ssl_ctx,
448 		    keypair->cert_mem, keypair->cert_len) != 1) {
449 			tls_set_errorx(ctx, "failed to load certificate");
450 			goto err;
451 		}
452 	}
453 
454 	if (tls_keypair_to_pkey(ctx, keypair, &pkey) == -1)
455 		goto err;
456 	if (pkey != NULL) {
457 		if (tls_keypair_setup_pkey(ctx, keypair, pkey) == -1)
458 			goto err;
459 		if (SSL_CTX_use_PrivateKey(ssl_ctx, pkey) != 1) {
460 			tls_set_errorx(ctx, "failed to load private key");
461 			goto err;
462 		}
463 		EVP_PKEY_free(pkey);
464 		pkey = NULL;
465 	}
466 
467 	if (!ctx->config->skip_private_key_check &&
468 	    SSL_CTX_check_private_key(ssl_ctx) != 1) {
469 		tls_set_errorx(ctx, "private/public key mismatch");
470 		goto err;
471 	}
472 
473 	return (0);
474 
475  err:
476 	EVP_PKEY_free(pkey);
477 
478 	return (-1);
479 }
480 
481 int
482 tls_configure_ssl(struct tls *ctx, SSL_CTX *ssl_ctx)
483 {
484 	SSL_CTX_clear_mode(ssl_ctx, SSL_MODE_AUTO_RETRY);
485 
486 	SSL_CTX_set_mode(ssl_ctx, SSL_MODE_ENABLE_PARTIAL_WRITE);
487 	SSL_CTX_set_mode(ssl_ctx, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
488 
489 	SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_SSLv2);
490 	SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_SSLv3);
491 
492 	SSL_CTX_clear_options(ssl_ctx, SSL_OP_NO_TLSv1);
493 	SSL_CTX_clear_options(ssl_ctx, SSL_OP_NO_TLSv1_1);
494 	SSL_CTX_clear_options(ssl_ctx, SSL_OP_NO_TLSv1_2);
495 	SSL_CTX_clear_options(ssl_ctx, SSL_OP_NO_TLSv1_3);
496 
497 	if ((ctx->config->protocols & TLS_PROTOCOL_TLSv1_0) == 0)
498 		SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_TLSv1);
499 	if ((ctx->config->protocols & TLS_PROTOCOL_TLSv1_1) == 0)
500 		SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_TLSv1_1);
501 	if ((ctx->config->protocols & TLS_PROTOCOL_TLSv1_2) == 0)
502 		SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_TLSv1_2);
503 	if ((ctx->config->protocols & TLS_PROTOCOL_TLSv1_3) == 0)
504 		SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_TLSv1_3);
505 
506 	if (ctx->config->alpn != NULL) {
507 		if (SSL_CTX_set_alpn_protos(ssl_ctx, ctx->config->alpn,
508 		    ctx->config->alpn_len) != 0) {
509 			tls_set_errorx(ctx, "failed to set alpn");
510 			goto err;
511 		}
512 	}
513 
514 	if (ctx->config->ciphers != NULL) {
515 		if (SSL_CTX_set_cipher_list(ssl_ctx,
516 		    ctx->config->ciphers) != 1) {
517 			tls_set_errorx(ctx, "failed to set ciphers");
518 			goto err;
519 		}
520 	}
521 
522 	if (ctx->config->verify_time == 0) {
523 		X509_VERIFY_PARAM_set_flags(SSL_CTX_get0_param(ssl_ctx),
524 		    X509_V_FLAG_NO_CHECK_TIME);
525 	}
526 
527 	/* Disable any form of session caching by default */
528 	SSL_CTX_set_session_cache_mode(ssl_ctx, SSL_SESS_CACHE_OFF);
529 	SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_TICKET);
530 
531 	return (0);
532 
533  err:
534 	return (-1);
535 }
536 
537 static int
538 tls_ssl_cert_verify_cb(X509_STORE_CTX *x509_ctx, void *arg)
539 {
540 	struct tls *ctx = arg;
541 	int x509_err;
542 
543 	if (ctx->config->verify_cert == 0)
544 		return (1);
545 
546 	if ((X509_verify_cert(x509_ctx)) < 0) {
547 		tls_set_errorx(ctx, "X509 verify cert failed");
548 		return (0);
549 	}
550 
551 	x509_err = X509_STORE_CTX_get_error(x509_ctx);
552 	if (x509_err == X509_V_OK)
553 		return (1);
554 
555 	tls_set_errorx(ctx, "certificate verification failed: %s",
556 	    X509_verify_cert_error_string(x509_err));
557 
558 	return (0);
559 }
560 
561 int
562 tls_configure_ssl_verify(struct tls *ctx, SSL_CTX *ssl_ctx, int verify)
563 {
564 	size_t ca_len = ctx->config->ca_len;
565 	char *ca_mem = ctx->config->ca_mem;
566 	char *crl_mem = ctx->config->crl_mem;
567 	size_t crl_len = ctx->config->crl_len;
568 	char *ca_free = NULL;
569 	STACK_OF(X509_INFO) *xis = NULL;
570 	X509_STORE *store;
571 	X509_INFO *xi;
572 	BIO *bio = NULL;
573 	int rv = -1;
574 	int i;
575 
576 	SSL_CTX_set_verify(ssl_ctx, verify, NULL);
577 	SSL_CTX_set_cert_verify_callback(ssl_ctx, tls_ssl_cert_verify_cb, ctx);
578 
579 	if (ctx->config->verify_depth >= 0)
580 		SSL_CTX_set_verify_depth(ssl_ctx, ctx->config->verify_depth);
581 
582 	if (ctx->config->verify_cert == 0)
583 		goto done;
584 
585 	/* If no CA has been specified, attempt to load the default. */
586 	if (ctx->config->ca_mem == NULL && ctx->config->ca_path == NULL) {
587 		if (tls_config_load_file(&ctx->error, "CA", tls_default_ca_cert_file(),
588 		    &ca_mem, &ca_len) != 0)
589 			goto err;
590 		ca_free = ca_mem;
591 	}
592 
593 	if (ca_mem != NULL) {
594 		if (ca_len > INT_MAX) {
595 			tls_set_errorx(ctx, "ca too long");
596 			goto err;
597 		}
598 		if (SSL_CTX_load_verify_mem(ssl_ctx, ca_mem, ca_len) != 1) {
599 			tls_set_errorx(ctx, "ssl verify memory setup failure");
600 			goto err;
601 		}
602 	} else if (SSL_CTX_load_verify_locations(ssl_ctx, NULL,
603 	    ctx->config->ca_path) != 1) {
604 		tls_set_errorx(ctx, "ssl verify locations failure");
605 		goto err;
606 	}
607 
608 	if (crl_mem != NULL) {
609 		if (crl_len > INT_MAX) {
610 			tls_set_errorx(ctx, "crl too long");
611 			goto err;
612 		}
613 		if ((bio = BIO_new_mem_buf(crl_mem, crl_len)) == NULL) {
614 			tls_set_errorx(ctx, "failed to create buffer");
615 			goto err;
616 		}
617 		if ((xis = PEM_X509_INFO_read_bio(bio, NULL, tls_password_cb,
618 		    NULL)) == NULL) {
619 			tls_set_errorx(ctx, "failed to parse crl");
620 			goto err;
621 		}
622 		store = SSL_CTX_get_cert_store(ssl_ctx);
623 		for (i = 0; i < sk_X509_INFO_num(xis); i++) {
624 			xi = sk_X509_INFO_value(xis, i);
625 			if (xi->crl == NULL)
626 				continue;
627 			if (!X509_STORE_add_crl(store, xi->crl)) {
628 				tls_set_error(ctx, "failed to add crl");
629 				goto err;
630 			}
631 		}
632 		X509_STORE_set_flags(store,
633 		    X509_V_FLAG_CRL_CHECK | X509_V_FLAG_CRL_CHECK_ALL);
634 	}
635 
636  done:
637 	rv = 0;
638 
639  err:
640 	sk_X509_INFO_pop_free(xis, X509_INFO_free);
641 	BIO_free(bio);
642 	free(ca_free);
643 
644 	return (rv);
645 }
646 
647 void
648 tls_free(struct tls *ctx)
649 {
650 	if (ctx == NULL)
651 		return;
652 
653 	tls_reset(ctx);
654 
655 	free(ctx);
656 }
657 
658 void
659 tls_reset(struct tls *ctx)
660 {
661 	struct tls_sni_ctx *sni, *nsni;
662 
663 	tls_config_free(ctx->config);
664 	ctx->config = NULL;
665 
666 	SSL_CTX_free(ctx->ssl_ctx);
667 	SSL_free(ctx->ssl_conn);
668 	X509_free(ctx->ssl_peer_cert);
669 
670 	ctx->ssl_conn = NULL;
671 	ctx->ssl_ctx = NULL;
672 	ctx->ssl_peer_cert = NULL;
673 	/* X509 objects in chain are freed with the SSL */
674 	ctx->ssl_peer_chain = NULL;
675 
676 	ctx->socket = -1;
677 	ctx->state = 0;
678 
679 	free(ctx->servername);
680 	ctx->servername = NULL;
681 
682 	free(ctx->error.msg);
683 	ctx->error.msg = NULL;
684 	ctx->error.num = -1;
685 
686 	tls_conninfo_free(ctx->conninfo);
687 	ctx->conninfo = NULL;
688 
689 	tls_ocsp_free(ctx->ocsp);
690 	ctx->ocsp = NULL;
691 
692 	for (sni = ctx->sni_ctx; sni != NULL; sni = nsni) {
693 		nsni = sni->next;
694 		tls_sni_ctx_free(sni);
695 	}
696 	ctx->sni_ctx = NULL;
697 
698 	ctx->read_cb = NULL;
699 	ctx->write_cb = NULL;
700 	ctx->cb_arg = NULL;
701 }
702 
703 int
704 tls_ssl_error(struct tls *ctx, SSL *ssl_conn, int ssl_ret, const char *prefix)
705 {
706 	const char *errstr = "unknown error";
707 	unsigned long err;
708 	int ssl_err;
709 
710 	ssl_err = SSL_get_error(ssl_conn, ssl_ret);
711 	switch (ssl_err) {
712 	case SSL_ERROR_NONE:
713 	case SSL_ERROR_ZERO_RETURN:
714 		return (0);
715 
716 	case SSL_ERROR_WANT_READ:
717 		return (TLS_WANT_POLLIN);
718 
719 	case SSL_ERROR_WANT_WRITE:
720 		return (TLS_WANT_POLLOUT);
721 
722 	case SSL_ERROR_SYSCALL:
723 		if ((err = ERR_peek_error()) != 0) {
724 			errstr = ERR_error_string(err, NULL);
725 		} else if (ssl_ret == 0) {
726 			if ((ctx->state & TLS_HANDSHAKE_COMPLETE) != 0) {
727 				ctx->state |= TLS_EOF_NO_CLOSE_NOTIFY;
728 				return (0);
729 			}
730 			errstr = "unexpected EOF";
731 		} else if (ssl_ret == -1) {
732 			errstr = strerror(errno);
733 		}
734 		tls_set_ssl_errorx(ctx, "%s failed: %s", prefix, errstr);
735 		return (-1);
736 
737 	case SSL_ERROR_SSL:
738 		if ((err = ERR_peek_error()) != 0) {
739 			errstr = ERR_error_string(err, NULL);
740 		}
741 		tls_set_ssl_errorx(ctx, "%s failed: %s", prefix, errstr);
742 		return (-1);
743 
744 	case SSL_ERROR_WANT_CONNECT:
745 	case SSL_ERROR_WANT_ACCEPT:
746 	case SSL_ERROR_WANT_X509_LOOKUP:
747 	default:
748 		tls_set_ssl_errorx(ctx, "%s failed (%d)", prefix, ssl_err);
749 		return (-1);
750 	}
751 }
752 
753 int
754 tls_handshake(struct tls *ctx)
755 {
756 	int rv = -1;
757 
758 	tls_error_clear(&ctx->error);
759 
760 	if ((ctx->flags & (TLS_CLIENT | TLS_SERVER_CONN)) == 0) {
761 		tls_set_errorx(ctx, "invalid operation for context");
762 		goto out;
763 	}
764 
765 	if ((ctx->state & TLS_HANDSHAKE_COMPLETE) != 0) {
766 		tls_set_errorx(ctx, "handshake already completed");
767 		goto out;
768 	}
769 
770 	if ((ctx->flags & TLS_CLIENT) != 0)
771 		rv = tls_handshake_client(ctx);
772 	else if ((ctx->flags & TLS_SERVER_CONN) != 0)
773 		rv = tls_handshake_server(ctx);
774 
775 	if (rv == 0) {
776 		ctx->ssl_peer_cert = SSL_get_peer_certificate(ctx->ssl_conn);
777 		ctx->ssl_peer_chain = SSL_get_peer_cert_chain(ctx->ssl_conn);
778 		if (tls_conninfo_populate(ctx) == -1)
779 			rv = -1;
780 		if (ctx->ocsp == NULL)
781 			ctx->ocsp = tls_ocsp_setup_from_peer(ctx);
782 	}
783  out:
784 	/* Prevent callers from performing incorrect error handling */
785 	errno = 0;
786 	return (rv);
787 }
788 
789 ssize_t
790 tls_read(struct tls *ctx, void *buf, size_t buflen)
791 {
792 	ssize_t rv = -1;
793 	int ssl_ret;
794 
795 	tls_error_clear(&ctx->error);
796 
797 	if ((ctx->state & TLS_HANDSHAKE_COMPLETE) == 0) {
798 		if ((rv = tls_handshake(ctx)) != 0)
799 			goto out;
800 	}
801 
802 	if (buflen > INT_MAX) {
803 		tls_set_errorx(ctx, "buflen too long");
804 		goto out;
805 	}
806 
807 	ERR_clear_error();
808 	if ((ssl_ret = SSL_read(ctx->ssl_conn, buf, buflen)) > 0) {
809 		rv = (ssize_t)ssl_ret;
810 		goto out;
811 	}
812 	rv = (ssize_t)tls_ssl_error(ctx, ctx->ssl_conn, ssl_ret, "read");
813 
814  out:
815 	/* Prevent callers from performing incorrect error handling */
816 	errno = 0;
817 	return (rv);
818 }
819 
820 ssize_t
821 tls_write(struct tls *ctx, const void *buf, size_t buflen)
822 {
823 	ssize_t rv = -1;
824 	int ssl_ret;
825 
826 	tls_error_clear(&ctx->error);
827 
828 	if ((ctx->state & TLS_HANDSHAKE_COMPLETE) == 0) {
829 		if ((rv = tls_handshake(ctx)) != 0)
830 			goto out;
831 	}
832 
833 	if (buflen > INT_MAX) {
834 		tls_set_errorx(ctx, "buflen too long");
835 		goto out;
836 	}
837 
838 	ERR_clear_error();
839 	if ((ssl_ret = SSL_write(ctx->ssl_conn, buf, buflen)) > 0) {
840 		rv = (ssize_t)ssl_ret;
841 		goto out;
842 	}
843 	rv = (ssize_t)tls_ssl_error(ctx, ctx->ssl_conn, ssl_ret, "write");
844 
845  out:
846 	/* Prevent callers from performing incorrect error handling */
847 	errno = 0;
848 	return (rv);
849 }
850 
851 int
852 tls_close(struct tls *ctx)
853 {
854 	int ssl_ret;
855 	int rv = 0;
856 
857 	tls_error_clear(&ctx->error);
858 
859 	if ((ctx->flags & (TLS_CLIENT | TLS_SERVER_CONN)) == 0) {
860 		tls_set_errorx(ctx, "invalid operation for context");
861 		rv = -1;
862 		goto out;
863 	}
864 
865 	if (ctx->state & TLS_SSL_NEEDS_SHUTDOWN) {
866 		ERR_clear_error();
867 		ssl_ret = SSL_shutdown(ctx->ssl_conn);
868 		if (ssl_ret < 0) {
869 			rv = tls_ssl_error(ctx, ctx->ssl_conn, ssl_ret,
870 			    "shutdown");
871 			if (rv == TLS_WANT_POLLIN || rv == TLS_WANT_POLLOUT)
872 				goto out;
873 		}
874 		ctx->state &= ~TLS_SSL_NEEDS_SHUTDOWN;
875 	}
876 
877 	if (ctx->socket != -1) {
878 		if (shutdown(ctx->socket, SHUT_RDWR) != 0) {
879 			if (rv == 0 &&
880 			    errno != ENOTCONN && errno != ECONNRESET) {
881 				tls_set_error(ctx, "shutdown");
882 				rv = -1;
883 			}
884 		}
885 		if (close(ctx->socket) != 0) {
886 			if (rv == 0) {
887 				tls_set_error(ctx, "close");
888 				rv = -1;
889 			}
890 		}
891 		ctx->socket = -1;
892 	}
893 
894 	if ((ctx->state & TLS_EOF_NO_CLOSE_NOTIFY) != 0) {
895 		tls_set_errorx(ctx, "EOF without close notify");
896 		rv = -1;
897 	}
898 
899  out:
900 	/* Prevent callers from performing incorrect error handling */
901 	errno = 0;
902 	return (rv);
903 }