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, const sdb_ssl_options_t *src)
141 {
142 sdb_ssl_options_t tmp;
143 sdb_ssl_options_t def = SDB_SSL_DEFAULT_OPTIONS;
145 if (src)
146 tmp = *src;
147 else
148 tmp = def;
150 if (! tmp.ca_file)
151 tmp.ca_file = def.ca_file;
152 if (! tmp.key_file)
153 tmp.key_file = def.key_file;
154 if (! tmp.cert_file)
155 tmp.cert_file = def.cert_file;
157 dst->ca_file = strdup(tmp.ca_file);
158 dst->key_file = strdup(tmp.key_file);
159 dst->cert_file = strdup(tmp.cert_file);
160 if ((! dst->ca_file) || (! dst->key_file) || (! dst->cert_file))
161 return -1;
162 if (tmp.crl_file) {
163 dst->crl_file = strdup(tmp.crl_file);
164 if (! dst->crl_file)
165 return -1;
166 }
167 return 0;
168 } /* copy_options */
170 /*
171 * public API
172 */
174 sdb_ssl_client_t *
175 sdb_ssl_client_create(const sdb_ssl_options_t *opts)
176 {
177 sdb_ssl_client_t *client;
179 client = calloc(1, sizeof(*client));
180 if (! client)
181 return NULL;
183 if (copy_options(&client->opts, opts)) {
184 sdb_ssl_client_destroy(client);
185 return NULL;
186 }
188 client->ctx = SSL_CTX_new(SSLv23_client_method());
189 if (! client->ctx) {
190 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL context");
191 sdb_ssl_client_destroy(client);
192 return NULL;
193 }
195 if (! SSL_CTX_load_verify_locations(client->ctx,
196 client->opts.ca_file, NULL)) {
197 ssl_log(SDB_LOG_ERR, "ssl: Failed to load CA file '%s'",
198 client->opts.ca_file);
199 sdb_ssl_client_destroy(client);
200 return NULL;
201 }
202 if (! SSL_CTX_use_certificate_file(client->ctx,
203 client->opts.cert_file, SSL_FILETYPE_PEM)) {
204 ssl_log(SDB_LOG_ERR, "ssl: Failed to load cert file '%s'",
205 client->opts.cert_file);
206 sdb_ssl_client_destroy(client);
207 return NULL;
208 }
209 if (! SSL_CTX_use_PrivateKey_file(client->ctx,
210 client->opts.key_file, SSL_FILETYPE_PEM)) {
211 ssl_log(SDB_LOG_ERR, "ssl: Failed to load key file '%s'",
212 client->opts.key_file);
213 sdb_ssl_client_destroy(client);
214 return NULL;
215 }
216 if (! SSL_CTX_check_private_key(client->ctx)) {
217 ssl_log(SDB_LOG_ERR, "ssl: Failed to verify key (%s)",
218 client->opts.key_file);
219 sdb_ssl_client_destroy(client);
220 return NULL;
221 }
223 SSL_CTX_set_mode(client->ctx, SSL_MODE_AUTO_RETRY);
224 SSL_CTX_set_verify(client->ctx, SSL_VERIFY_PEER, NULL);
225 SSL_CTX_set_verify_depth(client->ctx, 1);
226 return client;
227 } /* sdb_ssl_client_create */
229 void
230 sdb_ssl_client_destroy(sdb_ssl_client_t *client)
231 {
232 if (! client)
233 return;
235 if (client->ctx)
236 SSL_CTX_free(client->ctx);
237 sdb_ssl_free_options(&client->opts);
238 free(client);
239 } /* sdb_ssl_client_destroy */
241 sdb_ssl_session_t *
242 sdb_ssl_client_connect(sdb_ssl_client_t *client, int fd)
243 {
244 sdb_ssl_session_t *session;
245 int status;
246 BIO *bio;
248 if ((! client) || (fd < 0))
249 return NULL;
251 session = calloc(1, sizeof(*session));
252 if (! session)
253 return NULL;
255 bio = BIO_new_socket(fd, BIO_NOCLOSE);
256 if (! bio) {
257 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL socket");
258 sdb_ssl_session_destroy(session);
259 return NULL;
260 }
261 session->ssl = SSL_new(client->ctx);
262 if (! session->ssl) {
263 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL object");
264 sdb_ssl_session_destroy(session);
265 return NULL;
266 }
267 SSL_set_bio(session->ssl, bio, bio);
269 if ((status = SSL_connect(session->ssl)) <= 0) {
270 ssl_log_err(SDB_LOG_ERR, session->ssl, status,
271 "ssl: Failed to initialize SSL session");
272 sdb_ssl_session_destroy(session);
273 return NULL;
274 }
275 if (SSL_get_verify_result(session->ssl) != X509_V_OK) {
276 sdb_log(SDB_LOG_ERR, "Failed to verify SSL connection");
277 sdb_ssl_session_destroy(session);
278 return NULL;
279 }
280 return session;
281 } /* sdb_ssl_client_connect */
283 sdb_ssl_server_t *
284 sdb_ssl_server_create(const sdb_ssl_options_t *opts)
285 {
286 sdb_ssl_server_t *server;
288 server = calloc(1, sizeof(*server));
289 if (! server)
290 return NULL;
292 if (copy_options(&server->opts, opts)) {
293 sdb_ssl_server_destroy(server);
294 return NULL;
295 }
297 server->ctx = SSL_CTX_new(SSLv23_server_method());
298 if (! server->ctx) {
299 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL context");
300 sdb_ssl_server_destroy(server);
301 return NULL;
302 }
304 /* Recommendation documented at
305 * https://hynek.me/articles/hardening-your-web-servers-ssl-ciphers/ */
306 if (! SSL_CTX_set_cipher_list(server->ctx,
307 "ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:"
308 "DH+AES:ECDH+3DES:DH+3DES:RSA+AESGCM:RSA+AES:RSA+3DES:"
309 "!aNULL:!MD5:!DSS")) {
310 sdb_log(SDB_LOG_ERR, "ssl: Invalid cipher list");
311 sdb_ssl_server_destroy(server);
312 return NULL;
313 }
315 if (! SSL_CTX_load_verify_locations(server->ctx,
316 server->opts.ca_file, NULL)) {
317 ssl_log(SDB_LOG_ERR, "Failed to load CA file %s",
318 server->opts.ca_file);
319 return NULL;
320 }
321 SSL_CTX_set_client_CA_list(server->ctx,
322 SSL_load_client_CA_file(server->opts.ca_file));
324 if (! SSL_CTX_use_certificate_file(server->ctx,
325 server->opts.cert_file, SSL_FILETYPE_PEM)) {
326 ssl_log(SDB_LOG_ERR, "Failed to load SSL cert file %s",
327 server->opts.cert_file);
328 return NULL;
329 }
330 if (! SSL_CTX_use_PrivateKey_file(server->ctx,
331 server->opts.key_file, SSL_FILETYPE_PEM)) {
332 ssl_log(SDB_LOG_ERR, "Failed to load SSL key file %s",
333 server->opts.key_file);
334 return NULL;
335 }
336 if (! SSL_CTX_check_private_key(server->ctx)) {
337 ssl_log(SDB_LOG_ERR, "Failed to verify SSL private key");
338 return NULL;
339 }
341 SSL_CTX_set_mode(server->ctx, SSL_MODE_AUTO_RETRY);
342 SSL_CTX_set_verify(server->ctx,
343 SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, NULL);
344 SSL_CTX_set_verify_depth(server->ctx, 1);
346 /* TODO: handle server->opts.crl_file */
347 return server;
348 } /* sdb_ssl_server_create */
350 void
351 sdb_ssl_server_destroy(sdb_ssl_server_t *server)
352 {
353 if (! server)
354 return;
356 if (server->ctx)
357 SSL_CTX_free(server->ctx);
358 sdb_ssl_free_options(&server->opts);
359 free(server);
360 } /* sdb_ssl_server_destroy */
362 sdb_ssl_session_t *
363 sdb_ssl_server_accept(sdb_ssl_server_t *server, int fd)
364 {
365 sdb_ssl_session_t *session;
366 int status;
367 BIO *bio;
369 if ((! server) || (fd < 0))
370 return NULL;
372 session = calloc(1, sizeof(*session));
373 if (! session)
374 return NULL;
376 bio = BIO_new_socket(fd, BIO_NOCLOSE);
377 if (! bio) {
378 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL socket");
379 sdb_ssl_session_destroy(session);
380 return NULL;
381 }
382 session->ssl = SSL_new(server->ctx);
383 if (! session->ssl) {
384 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL object");
385 sdb_ssl_session_destroy(session);
386 return NULL;
387 }
388 SSL_set_bio(session->ssl, bio, bio);
390 while (42) {
391 if ((status = SSL_accept(session->ssl)) <= 0) {
392 if (SSL_get_error(session->ssl, status) == SSL_ERROR_WANT_READ)
393 continue;
395 ssl_log_err(SDB_LOG_ERR, session->ssl, status,
396 "ssl: Failed to initialize SSL session");
397 sdb_ssl_session_destroy(session);
398 return NULL;
399 }
400 break;
401 }
402 if (SSL_get_verify_result(session->ssl) != X509_V_OK) {
403 sdb_log(SDB_LOG_ERR, "Failed to verify SSL connection");
404 sdb_ssl_session_destroy(session);
405 return NULL;
406 }
407 return session;
408 } /* sdb_ssl_server_accept */
410 void
411 sdb_ssl_session_destroy(sdb_ssl_session_t *session)
412 {
413 if (! session)
414 return;
416 if (session->ssl) {
417 SSL_shutdown(session->ssl);
418 SSL_clear(session->ssl);
419 SSL_free(session->ssl);
420 }
421 free(session);
422 } /* sdb_ssl_session_destroy */
424 char *
425 sdb_ssl_session_peer(sdb_ssl_session_t *session)
426 {
427 X509 *x509;
428 X509_NAME *name;
430 char *peer = NULL;
431 char p[1024];
433 if (! session)
434 return NULL;
436 x509 = SSL_get_peer_certificate(session->ssl);
437 if (! x509)
438 return NULL;
439 name = X509_get_subject_name(x509);
440 if (! name) {
441 X509_free(x509);
442 return NULL;
443 }
445 if (X509_NAME_get_text_by_NID(name, NID_commonName, p, sizeof(p)) > 0)
446 peer = strdup(p);
448 X509_free(x509);
449 return peer;
450 } /* sdb_ssl_session_peer */
452 ssize_t
453 sdb_ssl_session_write(sdb_ssl_session_t *session, const void *buf, size_t n)
454 {
455 int status;
457 if (! session)
458 return -1;
460 status = SSL_write(session->ssl, buf, (int)n);
461 if (status) {
462 if ((status < 0) && (errno != EAGAIN))
463 ssl_log_err(SDB_LOG_ERR, session->ssl, status, "ssl: Write error");
464 return (ssize_t)status;
465 }
467 status = SSL_get_error(session->ssl, status);
468 if (status == SSL_ERROR_ZERO_RETURN)
469 return 0;
471 if ((status == SSL_ERROR_WANT_READ) || (status == SSL_ERROR_WANT_WRITE)) {
472 errno = EWOULDBLOCK;
473 return -1;
474 }
475 errno = ECONNRESET;
476 return -1;
477 } /* sdb_ssl_session_write */
479 ssize_t
480 sdb_ssl_session_read(sdb_ssl_session_t *session, void *buf, size_t n)
481 {
482 int status;
484 if (! session)
485 return -1;
487 status = SSL_read(session->ssl, buf, (int)n);
488 if (status) {
489 if ((status < 0) && (errno != EAGAIN))
490 ssl_log_err(SDB_LOG_ERR, session->ssl, status, "ssl: Read error");
491 return (ssize_t)status;
492 }
494 status = SSL_get_error(session->ssl, status);
495 if (status == SSL_ERROR_ZERO_RETURN)
496 return 0;
498 if ((status == SSL_ERROR_WANT_READ) || (status == SSL_ERROR_WANT_WRITE)) {
499 errno = EWOULDBLOCK;
500 return -1;
501 }
502 errno = ECONNRESET;
503 return -1;
504 } /* sdb_ssl_session_read */
506 void
507 sdb_ssl_free_options(sdb_ssl_options_t *opts)
508 {
509 if (! opts)
510 return;
512 if (opts->ca_file)
513 free(opts->ca_file);
514 if (opts->key_file)
515 free(opts->key_file);
516 if (opts->cert_file)
517 free(opts->cert_file);
518 if (opts->crl_file)
519 free(opts->crl_file);
521 opts->ca_file = opts->key_file = opts->cert_file = opts->crl_file = NULL;
522 } /* sdb_ssl_free_options */
524 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */