12beac528fbcfb36d9643469fb8213159ee6a80a
1 /*
2 * SysDB - src/utils/ssl.c
3 * Copyright (C) 2015 Sebastian 'tokkee' Harl <sh@tokkee.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
17 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
19 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
28 #if HAVE_CONFIG_H
29 # include "config.h"
30 #endif
32 #include "utils/ssl.h"
33 #include "utils/error.h"
35 #include <errno.h>
37 #include <stdlib.h>
38 #include <string.h>
40 #include <pthread.h>
42 #include <openssl/ssl.h>
43 #include <openssl/bio.h>
44 #include <openssl/crypto.h>
45 #include <openssl/x509.h>
46 #include <openssl/err.h>
48 /*
49 * data types
50 */
52 struct sdb_ssl_client {
53 SSL_CTX *ctx;
54 sdb_ssl_options_t opts;
55 };
57 struct sdb_ssl_server {
58 SSL_CTX *ctx;
59 sdb_ssl_options_t opts;
60 };
62 struct sdb_ssl_session {
63 SSL *ssl;
64 };
66 /*
67 * OpenSSL helper functions
68 */
70 static pthread_mutex_t *mutexes = NULL;
71 static int mutexes_num = 0;
73 static void
74 locking_callback(int mode, int n, const char *file, int line)
75 {
76 if (! mutexes) {
77 sdb_log(SDB_LOG_EMERG, "ssl: CRYPTO_lock called from %s:%d "
78 "before initializing SSL", file, line);
79 return;
80 }
81 if (n >= mutexes_num) {
82 sdb_log(SDB_LOG_EMERG, "ssl: CRYPTO_lock called from %s:%d "
83 "for mutex %d but only %d are available",
84 file, line, n, mutexes_num);
85 return;
86 }
88 if (mode & CRYPTO_LOCK)
89 pthread_mutex_lock(&mutexes[n]);
90 else
91 pthread_mutex_unlock(&mutexes[n]);
92 } /* locking_callback */
94 static void
95 threadid_callback(CRYPTO_THREADID *id)
96 {
97 CRYPTO_THREADID_set_numeric(id, (unsigned long)pthread_self());
98 } /* threadid_callback */
100 /*
101 * private helper functions
102 */
104 /* log all pending SSL errors */
105 static void
106 ssl_log(int prio, const char *prefix, ...)
107 {
108 char msg[1024];
109 va_list ap;
111 va_start(ap, prefix);
112 vsnprintf(msg, sizeof(msg), prefix, ap);
113 msg[sizeof(msg) - 1] = '\0';
114 va_end(ap);
116 while (42) {
117 unsigned long e = ERR_get_error();
118 if (! e)
119 break;
120 sdb_log(prio, "%s: %s", msg, ERR_reason_error_string(e));
121 }
122 } /* ssl_log */
124 static void
125 ssl_log_err(int prio, SSL *ssl, int status, const char *prefix, ...)
126 {
127 int err = SSL_get_error(ssl, status);
128 char msg[1024];
129 va_list ap;
131 va_start(ap, prefix);
132 vsnprintf(msg, sizeof(msg), prefix, ap);
133 msg[sizeof(msg) - 1] = '\0';
134 va_end(ap);
136 errno = 0;
137 switch (err) {
138 case SSL_ERROR_NONE:
139 sdb_log(prio, "%s: success", msg);
140 break;
141 case SSL_ERROR_ZERO_RETURN:
142 errno = ECONNRESET;
143 break;
144 case SSL_ERROR_WANT_READ:
145 case SSL_ERROR_WANT_WRITE:
146 errno = EWOULDBLOCK;
147 break;
148 case SSL_ERROR_WANT_CONNECT:
149 case SSL_ERROR_WANT_ACCEPT:
150 sdb_log(prio, "%s: connection not set up", msg);
151 break;
152 case SSL_ERROR_WANT_X509_LOOKUP:
153 sdb_log(prio, "%s: application error", msg);
154 break;
155 case SSL_ERROR_SYSCALL:
156 if (ERR_peek_error())
157 return ssl_log(prio, msg);
158 if (! status)
159 sdb_log(prio, "%s: unexpected end-of-file", msg);
160 else if (! errno)
161 errno = EIO;
162 case SSL_ERROR_SSL:
163 return ssl_log(prio, msg);
164 default:
165 sdb_log(prio, "%s: unkown SSL error %d", msg, err);
166 break;
167 }
169 if (errno) {
170 char errbuf[1024];
171 sdb_log(prio, "%s: %s", msg, sdb_strerror(errno, errbuf, sizeof(errbuf)));
172 }
173 } /* ssl_log_err */
175 static int
176 copy_options(sdb_ssl_options_t *dst, const sdb_ssl_options_t *src)
177 {
178 sdb_ssl_options_t tmp;
179 sdb_ssl_options_t def = SDB_SSL_DEFAULT_OPTIONS;
181 if (src)
182 tmp = *src;
183 else
184 tmp = def;
186 if (! tmp.ca_file)
187 tmp.ca_file = def.ca_file;
188 if (! tmp.key_file)
189 tmp.key_file = def.key_file;
190 if (! tmp.cert_file)
191 tmp.cert_file = def.cert_file;
193 dst->ca_file = strdup(tmp.ca_file);
194 dst->key_file = strdup(tmp.key_file);
195 dst->cert_file = strdup(tmp.cert_file);
196 if ((! dst->ca_file) || (! dst->key_file) || (! dst->cert_file))
197 return -1;
198 if (tmp.crl_file) {
199 dst->crl_file = strdup(tmp.crl_file);
200 if (! dst->crl_file)
201 return -1;
202 }
203 return 0;
204 } /* copy_options */
206 /*
207 * public API
208 */
210 int
211 sdb_ssl_init(void)
212 {
213 int i;
215 SSL_load_error_strings();
216 OpenSSL_add_ssl_algorithms();
218 mutexes = calloc(CRYPTO_num_locks(), sizeof(*mutexes));
219 if (! mutexes) {
220 char errbuf[1024];
221 sdb_log(SDB_LOG_ERR, "ssl: Failed to allocate mutexes: %s",
222 sdb_strerror(errno, errbuf, sizeof(errbuf)));
223 return -1;
224 }
225 for (i = 0; i < CRYPTO_num_locks(); ++i) {
226 errno = pthread_mutex_init(&mutexes[i], /* attr = */ NULL);
227 if (errno) {
228 char errbuf[1024];
229 sdb_log(SDB_LOG_ERR, "ssl: Failed to initialize mutex: %s",
230 sdb_strerror(errno, errbuf, sizeof(errbuf)));
231 return -1;
232 }
233 mutexes_num = i + 1;
234 }
236 CRYPTO_set_locking_callback(locking_callback);
237 CRYPTO_THREADID_set_callback(threadid_callback);
238 return 0;
239 } /* sdb_ssl_init */
241 void
242 sdb_ssl_shutdown(void)
243 {
244 int i;
246 ERR_free_strings();
248 for (i = 0; i < mutexes_num; ++i)
249 pthread_mutex_destroy(&mutexes[i]);
250 if (mutexes)
251 free(mutexes);
252 mutexes = NULL;
253 mutexes_num = 0;
254 } /* sdb_ssl_shutdown */
256 sdb_ssl_client_t *
257 sdb_ssl_client_create(const sdb_ssl_options_t *opts)
258 {
259 sdb_ssl_client_t *client;
261 client = calloc(1, sizeof(*client));
262 if (! client)
263 return NULL;
265 if (copy_options(&client->opts, opts)) {
266 sdb_ssl_client_destroy(client);
267 return NULL;
268 }
270 client->ctx = SSL_CTX_new(SSLv23_client_method());
271 if (! client->ctx) {
272 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL context");
273 sdb_ssl_client_destroy(client);
274 return NULL;
275 }
277 if (! SSL_CTX_load_verify_locations(client->ctx,
278 client->opts.ca_file, NULL)) {
279 ssl_log(SDB_LOG_ERR, "ssl: Failed to load CA file '%s'",
280 client->opts.ca_file);
281 sdb_ssl_client_destroy(client);
282 return NULL;
283 }
284 if (! SSL_CTX_use_certificate_file(client->ctx,
285 client->opts.cert_file, SSL_FILETYPE_PEM)) {
286 ssl_log(SDB_LOG_ERR, "ssl: Failed to load cert file '%s'",
287 client->opts.cert_file);
288 sdb_ssl_client_destroy(client);
289 return NULL;
290 }
291 if (! SSL_CTX_use_PrivateKey_file(client->ctx,
292 client->opts.key_file, SSL_FILETYPE_PEM)) {
293 ssl_log(SDB_LOG_ERR, "ssl: Failed to load key file '%s'",
294 client->opts.key_file);
295 sdb_ssl_client_destroy(client);
296 return NULL;
297 }
298 if (! SSL_CTX_check_private_key(client->ctx)) {
299 ssl_log(SDB_LOG_ERR, "ssl: Failed to verify key (%s)",
300 client->opts.key_file);
301 sdb_ssl_client_destroy(client);
302 return NULL;
303 }
305 SSL_CTX_set_mode(client->ctx, SSL_MODE_AUTO_RETRY);
306 SSL_CTX_set_verify(client->ctx, SSL_VERIFY_PEER, NULL);
307 SSL_CTX_set_verify_depth(client->ctx, 1);
308 return client;
309 } /* sdb_ssl_client_create */
311 void
312 sdb_ssl_client_destroy(sdb_ssl_client_t *client)
313 {
314 if (! client)
315 return;
317 if (client->ctx)
318 SSL_CTX_free(client->ctx);
319 sdb_ssl_free_options(&client->opts);
320 free(client);
321 } /* sdb_ssl_client_destroy */
323 sdb_ssl_session_t *
324 sdb_ssl_client_connect(sdb_ssl_client_t *client, int fd)
325 {
326 sdb_ssl_session_t *session;
327 int status;
328 BIO *bio;
330 if ((! client) || (fd < 0))
331 return NULL;
333 session = calloc(1, sizeof(*session));
334 if (! session)
335 return NULL;
337 bio = BIO_new_socket(fd, BIO_NOCLOSE);
338 if (! bio) {
339 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL socket");
340 sdb_ssl_session_destroy(session);
341 return NULL;
342 }
343 session->ssl = SSL_new(client->ctx);
344 if (! session->ssl) {
345 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL object");
346 sdb_ssl_session_destroy(session);
347 return NULL;
348 }
349 SSL_set_bio(session->ssl, bio, bio);
351 if ((status = SSL_connect(session->ssl)) <= 0) {
352 ssl_log_err(SDB_LOG_ERR, session->ssl, status,
353 "ssl: Failed to initialize SSL session");
354 sdb_ssl_session_destroy(session);
355 return NULL;
356 }
357 if (SSL_get_verify_result(session->ssl) != X509_V_OK) {
358 sdb_log(SDB_LOG_ERR, "Failed to verify SSL connection");
359 sdb_ssl_session_destroy(session);
360 return NULL;
361 }
362 return session;
363 } /* sdb_ssl_client_connect */
365 sdb_ssl_server_t *
366 sdb_ssl_server_create(const sdb_ssl_options_t *opts)
367 {
368 sdb_ssl_server_t *server;
370 server = calloc(1, sizeof(*server));
371 if (! server)
372 return NULL;
374 if (copy_options(&server->opts, opts)) {
375 sdb_ssl_server_destroy(server);
376 return NULL;
377 }
379 server->ctx = SSL_CTX_new(SSLv23_server_method());
380 if (! server->ctx) {
381 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL context");
382 sdb_ssl_server_destroy(server);
383 return NULL;
384 }
386 /* Recommendation documented at
387 * https://hynek.me/articles/hardening-your-web-servers-ssl-ciphers/ */
388 if (! SSL_CTX_set_cipher_list(server->ctx,
389 "ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:"
390 "DH+AES:ECDH+3DES:DH+3DES:RSA+AESGCM:RSA+AES:RSA+3DES:"
391 "!aNULL:!MD5:!DSS")) {
392 sdb_log(SDB_LOG_ERR, "ssl: Invalid cipher list");
393 sdb_ssl_server_destroy(server);
394 return NULL;
395 }
397 if (! SSL_CTX_load_verify_locations(server->ctx,
398 server->opts.ca_file, NULL)) {
399 ssl_log(SDB_LOG_ERR, "Failed to load CA file %s",
400 server->opts.ca_file);
401 sdb_ssl_server_destroy(server);
402 return NULL;
403 }
404 SSL_CTX_set_client_CA_list(server->ctx,
405 SSL_load_client_CA_file(server->opts.ca_file));
407 if (! SSL_CTX_use_certificate_file(server->ctx,
408 server->opts.cert_file, SSL_FILETYPE_PEM)) {
409 ssl_log(SDB_LOG_ERR, "Failed to load SSL cert file %s",
410 server->opts.cert_file);
411 sdb_ssl_server_destroy(server);
412 return NULL;
413 }
414 if (! SSL_CTX_use_PrivateKey_file(server->ctx,
415 server->opts.key_file, SSL_FILETYPE_PEM)) {
416 ssl_log(SDB_LOG_ERR, "Failed to load SSL key file %s",
417 server->opts.key_file);
418 sdb_ssl_server_destroy(server);
419 return NULL;
420 }
421 if (! SSL_CTX_check_private_key(server->ctx)) {
422 ssl_log(SDB_LOG_ERR, "Failed to verify SSL private key");
423 sdb_ssl_server_destroy(server);
424 return NULL;
425 }
427 SSL_CTX_set_mode(server->ctx, SSL_MODE_AUTO_RETRY);
428 SSL_CTX_set_verify(server->ctx,
429 SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, NULL);
430 SSL_CTX_set_verify_depth(server->ctx, 1);
432 /* TODO: handle server->opts.crl_file */
433 return server;
434 } /* sdb_ssl_server_create */
436 void
437 sdb_ssl_server_destroy(sdb_ssl_server_t *server)
438 {
439 if (! server)
440 return;
442 if (server->ctx)
443 SSL_CTX_free(server->ctx);
444 sdb_ssl_free_options(&server->opts);
445 free(server);
446 } /* sdb_ssl_server_destroy */
448 sdb_ssl_session_t *
449 sdb_ssl_server_accept(sdb_ssl_server_t *server, int fd)
450 {
451 sdb_ssl_session_t *session;
452 int status;
453 BIO *bio;
455 if ((! server) || (fd < 0))
456 return NULL;
458 session = calloc(1, sizeof(*session));
459 if (! session)
460 return NULL;
462 bio = BIO_new_socket(fd, BIO_NOCLOSE);
463 if (! bio) {
464 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL socket");
465 sdb_ssl_session_destroy(session);
466 return NULL;
467 }
468 session->ssl = SSL_new(server->ctx);
469 if (! session->ssl) {
470 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL object");
471 sdb_ssl_session_destroy(session);
472 return NULL;
473 }
474 SSL_set_bio(session->ssl, bio, bio);
476 while (42) {
477 if ((status = SSL_accept(session->ssl)) <= 0) {
478 if (SSL_get_error(session->ssl, status) == SSL_ERROR_WANT_READ)
479 continue;
481 ssl_log_err(SDB_LOG_ERR, session->ssl, status,
482 "ssl: Failed to initialize SSL session");
483 sdb_ssl_session_destroy(session);
484 return NULL;
485 }
486 break;
487 }
488 if (SSL_get_verify_result(session->ssl) != X509_V_OK) {
489 sdb_log(SDB_LOG_ERR, "Failed to verify SSL connection");
490 sdb_ssl_session_destroy(session);
491 return NULL;
492 }
493 return session;
494 } /* sdb_ssl_server_accept */
496 void
497 sdb_ssl_session_destroy(sdb_ssl_session_t *session)
498 {
499 if (! session)
500 return;
502 if (session->ssl) {
503 SSL_shutdown(session->ssl);
504 SSL_clear(session->ssl);
505 SSL_free(session->ssl);
506 }
507 free(session);
508 } /* sdb_ssl_session_destroy */
510 char *
511 sdb_ssl_session_peer(sdb_ssl_session_t *session)
512 {
513 X509 *x509;
514 X509_NAME *name;
516 char *peer = NULL;
517 char p[1024];
519 if (! session)
520 return NULL;
522 x509 = SSL_get_peer_certificate(session->ssl);
523 if (! x509)
524 return NULL;
525 name = X509_get_subject_name(x509);
526 if (! name) {
527 X509_free(x509);
528 return NULL;
529 }
531 if (X509_NAME_get_text_by_NID(name, NID_commonName, p, sizeof(p)) > 0)
532 peer = strdup(p);
534 X509_free(x509);
535 return peer;
536 } /* sdb_ssl_session_peer */
538 ssize_t
539 sdb_ssl_session_write(sdb_ssl_session_t *session, const void *buf, size_t n)
540 {
541 int status;
543 if (! session)
544 return -1;
546 status = SSL_write(session->ssl, buf, (int)n);
547 if (status) {
548 if ((status < 0) && (errno != EAGAIN))
549 ssl_log_err(SDB_LOG_ERR, session->ssl, status, "ssl: Write error");
550 return (ssize_t)status;
551 }
553 status = SSL_get_error(session->ssl, status);
554 if (status == SSL_ERROR_ZERO_RETURN)
555 return 0;
557 if ((status == SSL_ERROR_WANT_READ) || (status == SSL_ERROR_WANT_WRITE)) {
558 errno = EWOULDBLOCK;
559 return -1;
560 }
561 errno = ECONNRESET;
562 return -1;
563 } /* sdb_ssl_session_write */
565 ssize_t
566 sdb_ssl_session_read(sdb_ssl_session_t *session, void *buf, size_t n)
567 {
568 int status;
570 if (! session)
571 return -1;
573 status = SSL_read(session->ssl, buf, (int)n);
574 if (status) {
575 if ((status < 0) && (errno != EAGAIN))
576 ssl_log_err(SDB_LOG_ERR, session->ssl, status, "ssl: Read error");
577 return (ssize_t)status;
578 }
580 status = SSL_get_error(session->ssl, status);
581 if (status == SSL_ERROR_ZERO_RETURN)
582 return 0;
584 if ((status == SSL_ERROR_WANT_READ) || (status == SSL_ERROR_WANT_WRITE)) {
585 errno = EWOULDBLOCK;
586 return -1;
587 }
588 errno = ECONNRESET;
589 return -1;
590 } /* sdb_ssl_session_read */
592 void
593 sdb_ssl_free_options(sdb_ssl_options_t *opts)
594 {
595 if (! opts)
596 return;
598 if (opts->ca_file)
599 free(opts->ca_file);
600 if (opts->key_file)
601 free(opts->key_file);
602 if (opts->cert_file)
603 free(opts->cert_file);
604 if (opts->crl_file)
605 free(opts->crl_file);
607 opts->ca_file = opts->key_file = opts->cert_file = opts->crl_file = NULL;
608 } /* sdb_ssl_free_options */
610 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */