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 <openssl/ssl.h>
41 #include <openssl/bio.h>
42 #include <openssl/x509.h>
43 #include <openssl/err.h>
45 /*
46 * data types
47 */
49 struct sdb_ssl_client {
50 SSL_CTX *ctx;
51 sdb_ssl_options_t opts;
52 };
54 struct sdb_ssl_server {
55 SSL_CTX *ctx;
56 sdb_ssl_options_t opts;
57 };
59 struct sdb_ssl_session {
60 SSL *ssl;
61 };
63 /*
64 * private helper functions
65 */
67 /* log all pending SSL errors */
68 static void
69 ssl_log(int prio, const char *prefix, ...)
70 {
71 char msg[1024];
72 va_list ap;
74 va_start(ap, prefix);
75 vsnprintf(msg, sizeof(msg), prefix, ap);
76 msg[sizeof(msg) - 1] = '\0';
77 va_end(ap);
79 while (42) {
80 unsigned long e = ERR_get_error();
81 if (! e)
82 break;
83 sdb_log(prio, "%s: %s", msg, ERR_reason_error_string(e));
84 }
85 } /* ssl_log */
87 static void
88 ssl_log_err(int prio, SSL *ssl, int status, const char *prefix, ...)
89 {
90 int err = SSL_get_error(ssl, status);
91 char msg[1024];
92 va_list ap;
94 va_start(ap, prefix);
95 vsnprintf(msg, sizeof(msg), prefix, ap);
96 msg[sizeof(msg) - 1] = '\0';
97 va_end(ap);
99 errno = 0;
100 switch (err) {
101 case SSL_ERROR_NONE:
102 sdb_log(prio, "%s: success", msg);
103 break;
104 case SSL_ERROR_ZERO_RETURN:
105 errno = ECONNRESET;
106 break;
107 case SSL_ERROR_WANT_READ:
108 case SSL_ERROR_WANT_WRITE:
109 errno = EWOULDBLOCK;
110 break;
111 case SSL_ERROR_WANT_CONNECT:
112 case SSL_ERROR_WANT_ACCEPT:
113 sdb_log(prio, "%s: connection not set up", msg);
114 break;
115 case SSL_ERROR_WANT_X509_LOOKUP:
116 sdb_log(prio, "%s: application error", msg);
117 break;
118 case SSL_ERROR_SYSCALL:
119 if (ERR_peek_error())
120 return ssl_log(prio, msg);
121 if (! status)
122 sdb_log(prio, "%s: unexpected end-of-file", msg);
123 else if (! errno)
124 errno = EIO;
125 case SSL_ERROR_SSL:
126 return ssl_log(prio, msg);
127 default:
128 sdb_log(prio, "%s: unkown SSL error %d", msg, err);
129 break;
130 }
132 if (errno) {
133 char errbuf[1024];
134 sdb_log(prio, "%s: %s", msg,
135 sdb_strerror(errno, errbuf, sizeof(errbuf)));
136 }
137 } /* ssl_log_err */
139 static int
140 copy_options(sdb_ssl_options_t *dst, sdb_ssl_options_t *src)
141 {
142 sdb_ssl_options_t def = SDB_SSL_DEFAULT_OPTIONS;
144 if (! src)
145 src = &def;
147 if (! src->ca_file)
148 src->ca_file = def.ca_file;
149 if (! src->key_file)
150 src->key_file = def.key_file;
151 if (! src->cert_file)
152 src->cert_file = def.cert_file;
154 dst->ca_file = strdup(src->ca_file);
155 dst->key_file = strdup(src->key_file);
156 dst->cert_file = strdup(src->cert_file);
157 if ((! dst->ca_file) || (! dst->key_file) || (! dst->cert_file))
158 return -1;
159 if (src->crl_file) {
160 dst->crl_file = strdup(src->crl_file);
161 if (! dst->crl_file)
162 return -1;
163 }
164 return 0;
165 } /* copy_options */
167 /*
168 * public API
169 */
171 sdb_ssl_client_t *
172 sdb_ssl_client_create(sdb_ssl_options_t *opts)
173 {
174 sdb_ssl_client_t *client;
176 client = calloc(1, sizeof(*client));
177 if (! client)
178 return NULL;
180 if (copy_options(&client->opts, opts)) {
181 sdb_ssl_client_destroy(client);
182 return NULL;
183 }
185 client->ctx = SSL_CTX_new(SSLv23_client_method());
186 if (! client->ctx) {
187 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL context");
188 sdb_ssl_client_destroy(client);
189 return NULL;
190 }
192 if (! SSL_CTX_load_verify_locations(client->ctx,
193 client->opts.ca_file, NULL)) {
194 ssl_log(SDB_LOG_ERR, "ssl: Failed to load CA file");
195 sdb_ssl_client_destroy(client);
196 return NULL;
197 }
198 if (! SSL_CTX_use_certificate_file(client->ctx,
199 client->opts.cert_file, SSL_FILETYPE_PEM)) {
200 ssl_log(SDB_LOG_ERR, "ssl: Failed to load cert file '%s'",
201 client->opts.cert_file);
202 sdb_ssl_client_destroy(client);
203 return NULL;
204 }
205 if (! SSL_CTX_use_PrivateKey_file(client->ctx,
206 client->opts.key_file, SSL_FILETYPE_PEM)) {
207 ssl_log(SDB_LOG_ERR, "ssl: Failed to load key file '%s'",
208 client->opts.key_file);
209 sdb_ssl_client_destroy(client);
210 return NULL;
211 }
212 if (! SSL_CTX_check_private_key(client->ctx)) {
213 ssl_log(SDB_LOG_ERR, "ssl: Failed to verify key (%s)",
214 client->opts.key_file);
215 sdb_ssl_client_destroy(client);
216 return NULL;
217 }
219 SSL_CTX_set_mode(client->ctx, SSL_MODE_AUTO_RETRY);
220 SSL_CTX_set_verify(client->ctx, SSL_VERIFY_PEER, NULL);
221 SSL_CTX_set_verify_depth(client->ctx, 1);
222 return client;
223 } /* sdb_ssl_client_create */
225 void
226 sdb_ssl_client_destroy(sdb_ssl_client_t *client)
227 {
228 if (! client)
229 return;
231 if (client->ctx)
232 SSL_CTX_free(client->ctx);
233 sdb_ssl_free_options(&client->opts);
234 free(client);
235 } /* sdb_ssl_client_destroy */
237 sdb_ssl_session_t *
238 sdb_ssl_client_connect(sdb_ssl_client_t *client, int fd)
239 {
240 sdb_ssl_session_t *session;
241 int status;
242 BIO *bio;
244 if ((! client) || (fd < 0))
245 return NULL;
247 session = calloc(1, sizeof(*session));
248 if (! session)
249 return NULL;
251 bio = BIO_new_socket(fd, BIO_NOCLOSE);
252 if (! bio) {
253 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL socket");
254 sdb_ssl_session_destroy(session);
255 return NULL;
256 }
257 session->ssl = SSL_new(client->ctx);
258 if (! session->ssl) {
259 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL object");
260 sdb_ssl_session_destroy(session);
261 return NULL;
262 }
263 SSL_set_bio(session->ssl, bio, bio);
265 if ((status = SSL_connect(session->ssl)) <= 0) {
266 ssl_log_err(SDB_LOG_ERR, session->ssl, status,
267 "ssl: Failed to initialize SSL session");
268 sdb_ssl_session_destroy(session);
269 return NULL;
270 }
271 if (SSL_get_verify_result(session->ssl) != X509_V_OK) {
272 sdb_log(SDB_LOG_ERR, "Failed to verify SSL connection");
273 sdb_ssl_session_destroy(session);
274 return NULL;
275 }
276 return session;
277 } /* sdb_ssl_client_connect */
279 sdb_ssl_server_t *
280 sdb_ssl_server_create(sdb_ssl_options_t *opts)
281 {
282 sdb_ssl_server_t *server;
284 server = calloc(1, sizeof(*server));
285 if (! server)
286 return NULL;
288 if (copy_options(&server->opts, opts)) {
289 sdb_ssl_server_destroy(server);
290 return NULL;
291 }
293 server->ctx = SSL_CTX_new(SSLv23_server_method());
294 if (! server->ctx) {
295 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL context");
296 sdb_ssl_server_destroy(server);
297 return NULL;
298 }
300 /* Recommendation documented at
301 * https://hynek.me/articles/hardening-your-web-servers-ssl-ciphers/ */
302 if (! SSL_CTX_set_cipher_list(server->ctx,
303 "ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:"
304 "DH+AES:ECDH+3DES:DH+3DES:RSA+AESGCM:RSA+AES:RSA+3DES:"
305 "!aNULL:!MD5:!DSS")) {
306 sdb_log(SDB_LOG_ERR, "ssl: Invalid cipher list");
307 sdb_ssl_server_destroy(server);
308 return NULL;
309 }
311 if (! SSL_CTX_load_verify_locations(server->ctx,
312 server->opts.ca_file, NULL)) {
313 ssl_log(SDB_LOG_ERR, "Failed to load CA file %s",
314 server->opts.ca_file);
315 return NULL;
316 }
317 SSL_CTX_set_client_CA_list(server->ctx,
318 SSL_load_client_CA_file(server->opts.ca_file));
320 if (! SSL_CTX_use_certificate_file(server->ctx,
321 server->opts.cert_file, SSL_FILETYPE_PEM)) {
322 ssl_log(SDB_LOG_ERR, "Failed to load SSL cert file %s",
323 server->opts.cert_file);
324 return NULL;
325 }
326 if (! SSL_CTX_use_PrivateKey_file(server->ctx,
327 server->opts.key_file, SSL_FILETYPE_PEM)) {
328 ssl_log(SDB_LOG_ERR, "Failed to load SSL key file %s",
329 server->opts.key_file);
330 return NULL;
331 }
332 if (! SSL_CTX_check_private_key(server->ctx)) {
333 ssl_log(SDB_LOG_ERR, "Failed to verify SSL private key");
334 return NULL;
335 }
337 SSL_CTX_set_mode(server->ctx, SSL_MODE_AUTO_RETRY);
338 SSL_CTX_set_verify(server->ctx,
339 SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, NULL);
340 SSL_CTX_set_verify_depth(server->ctx, 1);
342 /* TODO: handle server->opts.crl_file */
343 return server;
344 } /* sdb_ssl_server_create */
346 void
347 sdb_ssl_server_destroy(sdb_ssl_server_t *server)
348 {
349 if (! server)
350 return;
352 if (server->ctx)
353 SSL_CTX_free(server->ctx);
354 sdb_ssl_free_options(&server->opts);
355 free(server);
356 } /* sdb_ssl_server_destroy */
358 sdb_ssl_session_t *
359 sdb_ssl_server_accept(sdb_ssl_server_t *server, int fd)
360 {
361 sdb_ssl_session_t *session;
362 int status;
363 BIO *bio;
365 if ((! server) || (fd < 0))
366 return NULL;
368 session = calloc(1, sizeof(*session));
369 if (! session)
370 return NULL;
372 bio = BIO_new_socket(fd, BIO_NOCLOSE);
373 if (! bio) {
374 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL socket");
375 sdb_ssl_session_destroy(session);
376 return NULL;
377 }
378 session->ssl = SSL_new(server->ctx);
379 if (! session->ssl) {
380 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL object");
381 sdb_ssl_session_destroy(session);
382 return NULL;
383 }
384 SSL_set_bio(session->ssl, bio, bio);
386 while (42) {
387 if ((status = SSL_accept(session->ssl)) <= 0) {
388 if (SSL_get_error(session->ssl, status) == SSL_ERROR_WANT_READ)
389 continue;
391 ssl_log_err(SDB_LOG_ERR, session->ssl, status,
392 "ssl: Failed to initialize SSL session");
393 sdb_ssl_session_destroy(session);
394 return NULL;
395 }
396 break;
397 }
398 if (SSL_get_verify_result(session->ssl) != X509_V_OK) {
399 sdb_log(SDB_LOG_ERR, "Failed to verify SSL connection");
400 sdb_ssl_session_destroy(session);
401 return NULL;
402 }
403 return session;
404 } /* sdb_ssl_server_accept */
406 void
407 sdb_ssl_session_destroy(sdb_ssl_session_t *session)
408 {
409 if (! session)
410 return;
412 if (session->ssl) {
413 SSL_shutdown(session->ssl);
414 SSL_clear(session->ssl);
415 SSL_free(session->ssl);
416 }
417 free(session);
418 } /* sdb_ssl_session_destroy */
420 char *
421 sdb_ssl_session_peer(sdb_ssl_session_t *session)
422 {
423 X509 *x509;
424 X509_NAME *name;
426 char *peer = NULL;
427 char p[1024];
429 if (! session)
430 return NULL;
432 x509 = SSL_get_peer_certificate(session->ssl);
433 if (! x509)
434 return NULL;
435 name = X509_get_subject_name(x509);
436 if (! name) {
437 X509_free(x509);
438 return NULL;
439 }
441 if (X509_NAME_get_text_by_NID(name, NID_commonName, p, sizeof(p)) > 0)
442 peer = strdup(p);
444 X509_free(x509);
445 return peer;
446 } /* sdb_ssl_session_peer */
448 ssize_t
449 sdb_ssl_session_write(sdb_ssl_session_t *session, const void *buf, size_t n)
450 {
451 int status;
453 if (! session)
454 return -1;
456 status = SSL_write(session->ssl, buf, (int)n);
457 if (status) {
458 if ((status < 0) && (errno != EAGAIN))
459 ssl_log_err(SDB_LOG_ERR, session->ssl, status, "ssl: Write error");
460 return (ssize_t)status;
461 }
463 status = SSL_get_error(session->ssl, status);
464 if (status == SSL_ERROR_ZERO_RETURN)
465 return 0;
467 if ((status == SSL_ERROR_WANT_READ) || (status == SSL_ERROR_WANT_WRITE)) {
468 errno = EWOULDBLOCK;
469 return -1;
470 }
471 errno = ECONNRESET;
472 return -1;
473 } /* sdb_ssl_session_write */
475 ssize_t
476 sdb_ssl_session_read(sdb_ssl_session_t *session, void *buf, size_t n)
477 {
478 int status;
480 if (! session)
481 return -1;
483 status = SSL_read(session->ssl, buf, (int)n);
484 if (status) {
485 if ((status < 0) && (errno != EAGAIN))
486 ssl_log_err(SDB_LOG_ERR, session->ssl, status, "ssl: Read error");
487 return (ssize_t)status;
488 }
490 status = SSL_get_error(session->ssl, status);
491 if (status == SSL_ERROR_ZERO_RETURN)
492 return 0;
494 if ((status == SSL_ERROR_WANT_READ) || (status == SSL_ERROR_WANT_WRITE)) {
495 errno = EWOULDBLOCK;
496 return -1;
497 }
498 errno = ECONNRESET;
499 return -1;
500 } /* sdb_ssl_session_read */
502 void
503 sdb_ssl_free_options(sdb_ssl_options_t *opts)
504 {
505 if (! opts)
506 return;
508 if (opts->ca_file)
509 free(opts->ca_file);
510 if (opts->key_file)
511 free(opts->key_file);
512 if (opts->cert_file)
513 free(opts->cert_file);
514 if (opts->crl_file)
515 free(opts->crl_file);
517 opts->ca_file = opts->key_file = opts->cert_file = opts->crl_file = NULL;
518 } /* sdb_ssl_free_options */
520 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */