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 static void
168 free_options(sdb_ssl_options_t *opts)
169 {
170 if (opts->ca_file)
171 free(opts->ca_file);
172 if (opts->key_file)
173 free(opts->key_file);
174 if (opts->cert_file)
175 free(opts->cert_file);
176 if (opts->crl_file)
177 free(opts->crl_file);
178 } /* free_options */
180 /*
181 * public API
182 */
184 sdb_ssl_client_t *
185 sdb_ssl_client_create(sdb_ssl_options_t *opts)
186 {
187 sdb_ssl_client_t *client;
189 client = calloc(1, sizeof(*client));
190 if (! client)
191 return NULL;
193 if (copy_options(&client->opts, opts)) {
194 sdb_ssl_client_destroy(client);
195 return NULL;
196 }
198 client->ctx = SSL_CTX_new(SSLv23_client_method());
199 if (! client->ctx) {
200 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL context");
201 sdb_ssl_client_destroy(client);
202 return NULL;
203 }
205 if (! SSL_CTX_load_verify_locations(client->ctx,
206 client->opts.ca_file, NULL)) {
207 ssl_log(SDB_LOG_ERR, "ssl: Failed to load CA file");
208 sdb_ssl_client_destroy(client);
209 return NULL;
210 }
211 if (! SSL_CTX_use_certificate_file(client->ctx,
212 client->opts.cert_file, SSL_FILETYPE_PEM)) {
213 ssl_log(SDB_LOG_ERR, "ssl: Failed to load cert file '%s'",
214 client->opts.cert_file);
215 sdb_ssl_client_destroy(client);
216 return NULL;
217 }
218 if (! SSL_CTX_use_PrivateKey_file(client->ctx,
219 client->opts.key_file, SSL_FILETYPE_PEM)) {
220 ssl_log(SDB_LOG_ERR, "ssl: Failed to load key file '%s'",
221 client->opts.key_file);
222 sdb_ssl_client_destroy(client);
223 return NULL;
224 }
225 if (! SSL_CTX_check_private_key(client->ctx)) {
226 ssl_log(SDB_LOG_ERR, "ssl: Failed to verify key (%s)",
227 client->opts.key_file);
228 sdb_ssl_client_destroy(client);
229 return NULL;
230 }
232 SSL_CTX_set_mode(client->ctx, SSL_MODE_AUTO_RETRY);
233 SSL_CTX_set_verify(client->ctx, SSL_VERIFY_PEER, NULL);
234 SSL_CTX_set_verify_depth(client->ctx, 1);
235 return client;
236 } /* sdb_ssl_client_create */
238 void
239 sdb_ssl_client_destroy(sdb_ssl_client_t *client)
240 {
241 if (! client)
242 return;
244 if (client->ctx)
245 SSL_CTX_free(client->ctx);
246 free_options(&client->opts);
247 free(client);
248 } /* sdb_ssl_client_destroy */
250 sdb_ssl_session_t *
251 sdb_ssl_client_connect(sdb_ssl_client_t *client, int fd)
252 {
253 sdb_ssl_session_t *session;
254 int status;
255 BIO *bio;
257 if ((! client) || (fd < 0))
258 return NULL;
260 session = calloc(1, sizeof(*session));
261 if (! session)
262 return NULL;
264 bio = BIO_new_socket(fd, BIO_NOCLOSE);
265 if (! bio) {
266 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL socket");
267 sdb_ssl_session_destroy(session);
268 return NULL;
269 }
270 session->ssl = SSL_new(client->ctx);
271 if (! session->ssl) {
272 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL object");
273 sdb_ssl_session_destroy(session);
274 return NULL;
275 }
276 SSL_set_bio(session->ssl, bio, bio);
278 if ((status = SSL_connect(session->ssl)) <= 0) {
279 ssl_log_err(SDB_LOG_ERR, session->ssl, status,
280 "ssl: Failed to initialize SSL session");
281 sdb_ssl_session_destroy(session);
282 return NULL;
283 }
284 if (SSL_get_verify_result(session->ssl) != X509_V_OK) {
285 sdb_log(SDB_LOG_ERR, "Failed to verify SSL connection");
286 sdb_ssl_session_destroy(session);
287 return NULL;
288 }
289 return session;
290 } /* sdb_ssl_client_connect */
292 sdb_ssl_server_t *
293 sdb_ssl_server_create(sdb_ssl_options_t *opts)
294 {
295 sdb_ssl_server_t *server;
297 server = calloc(1, sizeof(*server));
298 if (! server)
299 return NULL;
301 if (copy_options(&server->opts, opts)) {
302 sdb_ssl_server_destroy(server);
303 return NULL;
304 }
306 server->ctx = SSL_CTX_new(SSLv23_server_method());
307 if (! server->ctx) {
308 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL context");
309 sdb_ssl_server_destroy(server);
310 return NULL;
311 }
313 /* Recommendation documented at
314 * https://hynek.me/articles/hardening-your-web-servers-ssl-ciphers/ */
315 if (! SSL_CTX_set_cipher_list(server->ctx,
316 "ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:"
317 "DH+AES:ECDH+3DES:DH+3DES:RSA+AESGCM:RSA+AES:RSA+3DES:"
318 "!aNULL:!MD5:!DSS")) {
319 sdb_log(SDB_LOG_ERR, "ssl: Invalid cipher list");
320 sdb_ssl_server_destroy(server);
321 return NULL;
322 }
324 if (! SSL_CTX_load_verify_locations(server->ctx,
325 server->opts.ca_file, NULL)) {
326 ssl_log(SDB_LOG_ERR, "Failed to load CA file %s",
327 server->opts.ca_file);
328 return NULL;
329 }
330 SSL_CTX_set_client_CA_list(server->ctx,
331 SSL_load_client_CA_file(server->opts.ca_file));
333 if (! SSL_CTX_use_certificate_file(server->ctx,
334 server->opts.cert_file, SSL_FILETYPE_PEM)) {
335 ssl_log(SDB_LOG_ERR, "Failed to load SSL cert file %s",
336 server->opts.cert_file);
337 return NULL;
338 }
339 if (! SSL_CTX_use_PrivateKey_file(server->ctx,
340 server->opts.key_file, SSL_FILETYPE_PEM)) {
341 ssl_log(SDB_LOG_ERR, "Failed to load SSL key file %s",
342 server->opts.key_file);
343 return NULL;
344 }
345 if (! SSL_CTX_check_private_key(server->ctx)) {
346 ssl_log(SDB_LOG_ERR, "Failed to verify SSL private key");
347 return NULL;
348 }
350 SSL_CTX_set_mode(server->ctx, SSL_MODE_AUTO_RETRY);
351 SSL_CTX_set_verify(server->ctx,
352 SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, NULL);
353 SSL_CTX_set_verify_depth(server->ctx, 1);
355 /* TODO: handle server->opts.crl_file */
356 return server;
357 } /* sdb_ssl_server_create */
359 void
360 sdb_ssl_server_destroy(sdb_ssl_server_t *server)
361 {
362 if (! server)
363 return;
365 if (server->ctx)
366 SSL_CTX_free(server->ctx);
367 free_options(&server->opts);
368 free(server);
369 } /* sdb_ssl_server_destroy */
371 sdb_ssl_session_t *
372 sdb_ssl_server_accept(sdb_ssl_server_t *server, int fd)
373 {
374 sdb_ssl_session_t *session;
375 int status;
376 BIO *bio;
378 if ((! server) || (fd < 0))
379 return NULL;
381 session = calloc(1, sizeof(*session));
382 if (! session)
383 return NULL;
385 bio = BIO_new_socket(fd, BIO_NOCLOSE);
386 if (! bio) {
387 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL socket");
388 sdb_ssl_session_destroy(session);
389 return NULL;
390 }
391 session->ssl = SSL_new(server->ctx);
392 if (! session->ssl) {
393 ssl_log(SDB_LOG_ERR, "ssl: Failed to create SSL object");
394 sdb_ssl_session_destroy(session);
395 return NULL;
396 }
397 SSL_set_bio(session->ssl, bio, bio);
399 while (42) {
400 if ((status = SSL_accept(session->ssl)) <= 0) {
401 if (SSL_get_error(session->ssl, status) == SSL_ERROR_WANT_READ)
402 continue;
404 ssl_log_err(SDB_LOG_ERR, session->ssl, status,
405 "ssl: Failed to initialize SSL session");
406 sdb_ssl_session_destroy(session);
407 return NULL;
408 }
409 break;
410 }
411 if (SSL_get_verify_result(session->ssl) != X509_V_OK) {
412 sdb_log(SDB_LOG_ERR, "Failed to verify SSL connection");
413 sdb_ssl_session_destroy(session);
414 return NULL;
415 }
416 return session;
417 } /* sdb_ssl_server_accept */
419 void
420 sdb_ssl_session_destroy(sdb_ssl_session_t *session)
421 {
422 if (! session)
423 return;
425 if (session->ssl) {
426 SSL_shutdown(session->ssl);
427 SSL_clear(session->ssl);
428 SSL_free(session->ssl);
429 }
430 free(session);
431 } /* sdb_ssl_session_destroy */
433 char *
434 sdb_ssl_session_peer(sdb_ssl_session_t *session)
435 {
436 X509 *x509;
437 X509_NAME *name;
439 char *peer = NULL;
440 char p[1024];
442 if (! session)
443 return NULL;
445 x509 = SSL_get_peer_certificate(session->ssl);
446 if (! x509)
447 return NULL;
448 name = X509_get_subject_name(x509);
449 if (! name) {
450 X509_free(x509);
451 return NULL;
452 }
454 if (X509_NAME_get_text_by_NID(name, NID_commonName, p, sizeof(p)) > 0)
455 peer = strdup(p);
457 X509_free(x509);
458 return peer;
459 } /* sdb_ssl_session_peer */
461 ssize_t
462 sdb_ssl_session_write(sdb_ssl_session_t *session, const void *buf, size_t n)
463 {
464 int status;
466 if (! session)
467 return -1;
469 status = SSL_write(session->ssl, buf, (int)n);
470 if (status) {
471 if ((status < 0) && (errno != EAGAIN))
472 ssl_log_err(SDB_LOG_ERR, session->ssl, status, "ssl: Write error");
473 return (ssize_t)status;
474 }
476 status = SSL_get_error(session->ssl, status);
477 if (status == SSL_ERROR_ZERO_RETURN)
478 return 0;
480 if ((status == SSL_ERROR_WANT_READ) || (status == SSL_ERROR_WANT_WRITE)) {
481 errno = EWOULDBLOCK;
482 return -1;
483 }
484 errno = ECONNRESET;
485 return -1;
486 } /* sdb_ssl_session_write */
488 ssize_t
489 sdb_ssl_session_read(sdb_ssl_session_t *session, void *buf, size_t n)
490 {
491 int status;
493 if (! session)
494 return -1;
496 status = SSL_read(session->ssl, buf, (int)n);
497 if (status) {
498 if ((status < 0) && (errno != EAGAIN))
499 ssl_log_err(SDB_LOG_ERR, session->ssl, status, "ssl: Read error");
500 return (ssize_t)status;
501 }
503 status = SSL_get_error(session->ssl, status);
504 if (status == SSL_ERROR_ZERO_RETURN)
505 return 0;
507 if ((status == SSL_ERROR_WANT_READ) || (status == SSL_ERROR_WANT_WRITE)) {
508 errno = EWOULDBLOCK;
509 return -1;
510 }
511 errno = ECONNRESET;
512 return -1;
513 } /* sdb_ssl_session_read */
515 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */