d9ad060bb2270a86157135cb57e442b1a15af76e
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 '%s'",
195 client->opts.ca_file);
196 sdb_ssl_client_destroy(client);
197 return NULL;
198 }
199 if (! SSL_CTX_use_certificate_file(client->ctx,
200 client->opts.cert_file, SSL_FILETYPE_PEM)) {
201 ssl_log(SDB_LOG_ERR, "ssl: Failed to load cert file '%s'",
202 client->opts.cert_file);
203 sdb_ssl_client_destroy(client);
204 return NULL;
205 }
206 if (! SSL_CTX_use_PrivateKey_file(client->ctx,
207 client->opts.key_file, SSL_FILETYPE_PEM)) {
208 ssl_log(SDB_LOG_ERR, "ssl: Failed to load key file '%s'",
209 client->opts.key_file);
210 sdb_ssl_client_destroy(client);
211 return NULL;
212 }
213 if (! SSL_CTX_check_private_key(client->ctx)) {
214 ssl_log(SDB_LOG_ERR, "ssl: Failed to verify key (%s)",
215 client->opts.key_file);
216 sdb_ssl_client_destroy(client);
217 return NULL;
218 }
220 SSL_CTX_set_mode(client->ctx, SSL_MODE_AUTO_RETRY);
221 SSL_CTX_set_verify(client->ctx, SSL_VERIFY_PEER, NULL);
222 SSL_CTX_set_verify_depth(client->ctx, 1);
223 return client;
224 } /* sdb_ssl_client_create */
226 void
227 sdb_ssl_client_destroy(sdb_ssl_client_t *client)
228 {
229 if (! client)
230 return;
232 if (client->ctx)
233 SSL_CTX_free(client->ctx);
234 sdb_ssl_free_options(&client->opts);
235 free(client);
236 } /* sdb_ssl_client_destroy */
238 sdb_ssl_session_t *
239 sdb_ssl_client_connect(sdb_ssl_client_t *client, int fd)
240 {
241 sdb_ssl_session_t *session;
242 int status;
243 BIO *bio;
245 if ((! client) || (fd < 0))
246 return NULL;
248 session = calloc(1, sizeof(*session));
249 if (! session)
250 return NULL;
252 bio = BIO_new_socket(fd, BIO_NOCLOSE);
253 if (! bio) {
254 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL socket");
255 sdb_ssl_session_destroy(session);
256 return NULL;
257 }
258 session->ssl = SSL_new(client->ctx);
259 if (! session->ssl) {
260 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL object");
261 sdb_ssl_session_destroy(session);
262 return NULL;
263 }
264 SSL_set_bio(session->ssl, bio, bio);
266 if ((status = SSL_connect(session->ssl)) <= 0) {
267 ssl_log_err(SDB_LOG_ERR, session->ssl, status,
268 "ssl: Failed to initialize SSL session");
269 sdb_ssl_session_destroy(session);
270 return NULL;
271 }
272 if (SSL_get_verify_result(session->ssl) != X509_V_OK) {
273 sdb_log(SDB_LOG_ERR, "Failed to verify SSL connection");
274 sdb_ssl_session_destroy(session);
275 return NULL;
276 }
277 return session;
278 } /* sdb_ssl_client_connect */
280 sdb_ssl_server_t *
281 sdb_ssl_server_create(sdb_ssl_options_t *opts)
282 {
283 sdb_ssl_server_t *server;
285 server = calloc(1, sizeof(*server));
286 if (! server)
287 return NULL;
289 if (copy_options(&server->opts, opts)) {
290 sdb_ssl_server_destroy(server);
291 return NULL;
292 }
294 server->ctx = SSL_CTX_new(SSLv23_server_method());
295 if (! server->ctx) {
296 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL context");
297 sdb_ssl_server_destroy(server);
298 return NULL;
299 }
301 /* Recommendation documented at
302 * https://hynek.me/articles/hardening-your-web-servers-ssl-ciphers/ */
303 if (! SSL_CTX_set_cipher_list(server->ctx,
304 "ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:"
305 "DH+AES:ECDH+3DES:DH+3DES:RSA+AESGCM:RSA+AES:RSA+3DES:"
306 "!aNULL:!MD5:!DSS")) {
307 sdb_log(SDB_LOG_ERR, "ssl: Invalid cipher list");
308 sdb_ssl_server_destroy(server);
309 return NULL;
310 }
312 if (! SSL_CTX_load_verify_locations(server->ctx,
313 server->opts.ca_file, NULL)) {
314 ssl_log(SDB_LOG_ERR, "Failed to load CA file %s",
315 server->opts.ca_file);
316 return NULL;
317 }
318 SSL_CTX_set_client_CA_list(server->ctx,
319 SSL_load_client_CA_file(server->opts.ca_file));
321 if (! SSL_CTX_use_certificate_file(server->ctx,
322 server->opts.cert_file, SSL_FILETYPE_PEM)) {
323 ssl_log(SDB_LOG_ERR, "Failed to load SSL cert file %s",
324 server->opts.cert_file);
325 return NULL;
326 }
327 if (! SSL_CTX_use_PrivateKey_file(server->ctx,
328 server->opts.key_file, SSL_FILETYPE_PEM)) {
329 ssl_log(SDB_LOG_ERR, "Failed to load SSL key file %s",
330 server->opts.key_file);
331 return NULL;
332 }
333 if (! SSL_CTX_check_private_key(server->ctx)) {
334 ssl_log(SDB_LOG_ERR, "Failed to verify SSL private key");
335 return NULL;
336 }
338 SSL_CTX_set_mode(server->ctx, SSL_MODE_AUTO_RETRY);
339 SSL_CTX_set_verify(server->ctx,
340 SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, NULL);
341 SSL_CTX_set_verify_depth(server->ctx, 1);
343 /* TODO: handle server->opts.crl_file */
344 return server;
345 } /* sdb_ssl_server_create */
347 void
348 sdb_ssl_server_destroy(sdb_ssl_server_t *server)
349 {
350 if (! server)
351 return;
353 if (server->ctx)
354 SSL_CTX_free(server->ctx);
355 sdb_ssl_free_options(&server->opts);
356 free(server);
357 } /* sdb_ssl_server_destroy */
359 sdb_ssl_session_t *
360 sdb_ssl_server_accept(sdb_ssl_server_t *server, int fd)
361 {
362 sdb_ssl_session_t *session;
363 int status;
364 BIO *bio;
366 if ((! server) || (fd < 0))
367 return NULL;
369 session = calloc(1, sizeof(*session));
370 if (! session)
371 return NULL;
373 bio = BIO_new_socket(fd, BIO_NOCLOSE);
374 if (! bio) {
375 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL socket");
376 sdb_ssl_session_destroy(session);
377 return NULL;
378 }
379 session->ssl = SSL_new(server->ctx);
380 if (! session->ssl) {
381 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL object");
382 sdb_ssl_session_destroy(session);
383 return NULL;
384 }
385 SSL_set_bio(session->ssl, bio, bio);
387 while (42) {
388 if ((status = SSL_accept(session->ssl)) <= 0) {
389 if (SSL_get_error(session->ssl, status) == SSL_ERROR_WANT_READ)
390 continue;
392 ssl_log_err(SDB_LOG_ERR, session->ssl, status,
393 "ssl: Failed to initialize SSL session");
394 sdb_ssl_session_destroy(session);
395 return NULL;
396 }
397 break;
398 }
399 if (SSL_get_verify_result(session->ssl) != X509_V_OK) {
400 sdb_log(SDB_LOG_ERR, "Failed to verify SSL connection");
401 sdb_ssl_session_destroy(session);
402 return NULL;
403 }
404 return session;
405 } /* sdb_ssl_server_accept */
407 void
408 sdb_ssl_session_destroy(sdb_ssl_session_t *session)
409 {
410 if (! session)
411 return;
413 if (session->ssl) {
414 SSL_shutdown(session->ssl);
415 SSL_clear(session->ssl);
416 SSL_free(session->ssl);
417 }
418 free(session);
419 } /* sdb_ssl_session_destroy */
421 char *
422 sdb_ssl_session_peer(sdb_ssl_session_t *session)
423 {
424 X509 *x509;
425 X509_NAME *name;
427 char *peer = NULL;
428 char p[1024];
430 if (! session)
431 return NULL;
433 x509 = SSL_get_peer_certificate(session->ssl);
434 if (! x509)
435 return NULL;
436 name = X509_get_subject_name(x509);
437 if (! name) {
438 X509_free(x509);
439 return NULL;
440 }
442 if (X509_NAME_get_text_by_NID(name, NID_commonName, p, sizeof(p)) > 0)
443 peer = strdup(p);
445 X509_free(x509);
446 return peer;
447 } /* sdb_ssl_session_peer */
449 ssize_t
450 sdb_ssl_session_write(sdb_ssl_session_t *session, const void *buf, size_t n)
451 {
452 int status;
454 if (! session)
455 return -1;
457 status = SSL_write(session->ssl, buf, (int)n);
458 if (status) {
459 if ((status < 0) && (errno != EAGAIN))
460 ssl_log_err(SDB_LOG_ERR, session->ssl, status, "ssl: Write error");
461 return (ssize_t)status;
462 }
464 status = SSL_get_error(session->ssl, status);
465 if (status == SSL_ERROR_ZERO_RETURN)
466 return 0;
468 if ((status == SSL_ERROR_WANT_READ) || (status == SSL_ERROR_WANT_WRITE)) {
469 errno = EWOULDBLOCK;
470 return -1;
471 }
472 errno = ECONNRESET;
473 return -1;
474 } /* sdb_ssl_session_write */
476 ssize_t
477 sdb_ssl_session_read(sdb_ssl_session_t *session, void *buf, size_t n)
478 {
479 int status;
481 if (! session)
482 return -1;
484 status = SSL_read(session->ssl, buf, (int)n);
485 if (status) {
486 if ((status < 0) && (errno != EAGAIN))
487 ssl_log_err(SDB_LOG_ERR, session->ssl, status, "ssl: Read error");
488 return (ssize_t)status;
489 }
491 status = SSL_get_error(session->ssl, status);
492 if (status == SSL_ERROR_ZERO_RETURN)
493 return 0;
495 if ((status == SSL_ERROR_WANT_READ) || (status == SSL_ERROR_WANT_WRITE)) {
496 errno = EWOULDBLOCK;
497 return -1;
498 }
499 errno = ECONNRESET;
500 return -1;
501 } /* sdb_ssl_session_read */
503 void
504 sdb_ssl_free_options(sdb_ssl_options_t *opts)
505 {
506 if (! opts)
507 return;
509 if (opts->ca_file)
510 free(opts->ca_file);
511 if (opts->key_file)
512 free(opts->key_file);
513 if (opts->cert_file)
514 free(opts->cert_file);
515 if (opts->crl_file)
516 free(opts->crl_file);
518 opts->ca_file = opts->key_file = opts->cert_file = opts->crl_file = NULL;
519 } /* sdb_ssl_free_options */
521 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */