ngIRCd Release 26
[ngircd-alex.git] / src / ngircd / conn-ssl.c
1 /*
2  * ngIRCd -- The Next Generation IRC Daemon
3  * Copyright (c)2005-2008 Florian Westphal (fw@strlen.de).
4  * Copyright (c)2008-2014 Alexander Barton (alex@barton.de) and Contributors.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  * Please read the file COPYING, README and AUTHORS for more information.
11  */
12
13 #include "portab.h"
14
15 /**
16  * @file
17  * SSL wrapper functions
18  */
19
20 #include "conf-ssl.h"
21
22 #ifdef SSL_SUPPORT
23
24 #include "io.h"
25 #include <assert.h>
26 #include <stdio.h>
27 #include <string.h>
28 #include <stdlib.h>
29 #include <errno.h>
30
31 #define CONN_MODULE
32 #include "conn.h"
33 #include "conf.h"
34 #include "conn-func.h"
35 #include "conn-ssl.h"
36 #include "log.h"
37
38 #include "defines.h"
39
40 extern struct SSLOptions Conf_SSLOptions;
41
42 #ifdef HAVE_LIBSSL
43 #include <openssl/err.h>
44 #include <openssl/rand.h>
45 #include <openssl/dh.h>
46
47 static SSL_CTX * ssl_ctx;
48 static DH *dh_params;
49
50 static bool ConnSSL_LoadServerKey_openssl PARAMS(( SSL_CTX *c ));
51 #endif
52
53 #ifdef HAVE_LIBGNUTLS
54 #include <sys/types.h>
55 #include <sys/stat.h>
56 #include <fcntl.h>
57 #include <unistd.h>
58 #include <gnutls/x509.h>
59
60 #define DH_BITS 2048
61 #define DH_BITS_MIN 1024
62
63 #define MAX_HASH_SIZE   64      /* from gnutls-int.h */
64
65 typedef struct {
66         int refcnt;
67         gnutls_certificate_credentials_t x509_cred;
68         gnutls_dh_params_t dh_params;
69 } x509_cred_slot;
70
71 static array x509_creds = INIT_ARRAY;
72 static size_t x509_cred_idx;
73
74 static gnutls_dh_params_t dh_params;
75 static gnutls_priority_t priorities_cache = NULL;
76 static bool ConnSSL_LoadServerKey_gnutls PARAMS(( void ));
77 #endif
78
79 #define SHA256_STRING_LEN       (32 * 2 + 1)
80
81 static bool ConnSSL_Init_SSL PARAMS(( CONNECTION *c ));
82 static int ConnectAccept PARAMS(( CONNECTION *c, bool connect ));
83 static int ConnSSL_HandleError PARAMS(( CONNECTION *c, const int code, const char *fname ));
84
85 #ifdef HAVE_LIBGNUTLS
86 static char * openreadclose(const char *name, size_t *len)
87 {
88         char *buf = NULL;
89         struct stat s;
90         ssize_t br;
91         int fd = open(name, O_RDONLY);
92         if (fd < 0) {
93                 Log(LOG_ERR, "Could not open %s: %s", name, strerror(errno));
94                 return NULL;
95         }
96         if (fstat(fd, &s)) {
97                 Log(LOG_ERR, "Could not fstat %s: %s", name, strerror(errno));
98                 goto out;
99         }
100         if (!S_ISREG(s.st_mode)) {
101                 Log(LOG_ERR, "%s: Not a regular file", name);
102                 goto out;
103         }
104         if (s.st_size <= 0) {
105                 Log(LOG_ERR, "%s: invalid file length (size %ld <= 0)", name, (long) s.st_size);
106                 goto out;
107         }
108         buf = malloc(s.st_size);
109         if (!buf) {
110                 Log(LOG_ERR, "Could not malloc %lu bytes for file %s: %s", s.st_size, name, strerror(errno));
111                 goto out;
112         }
113         br = read(fd, buf, s.st_size);
114         if (br != (ssize_t)s.st_size) {
115                 Log(LOG_ERR, "Could not read file %s: read returned %ld, expected %ld: %s",
116                         name, (long) br, (long) s.st_size, br == -1 ? strerror(errno):"short read?!");
117                 memset(buf, 0, s.st_size);
118                 free(buf);
119                 buf = NULL;
120         } else {
121                 *len = br;
122         }
123 out:
124         close(fd);
125         return buf;
126 }
127 #endif
128
129
130 #ifdef HAVE_LIBSSL
131 /**
132  * Log OpenSSL error message.
133  *
134  * @param msg The error message.
135  * @param info Additional information text or NULL.
136  */
137 static void
138 LogOpenSSLError(const char *error, const char *info)
139 {
140         unsigned long err = ERR_get_error();
141         char * errmsg = err
142                 ? ERR_error_string(err, NULL)
143                 : "Unable to determine error";
144
145         assert(error != NULL);
146
147         if (info)
148                 Log(LOG_ERR, "%s: %s (%s)", error, info, errmsg);
149         else
150                 Log(LOG_ERR, "%s: %s", error, errmsg);
151 }
152
153
154 static int
155 pem_passwd_cb(char *buf, int size, int rwflag, void *password)
156 {
157         array *pass = password;
158         int passlen;
159
160         (void)rwflag;           /* rwflag is unused if DEBUG is not set. */
161         assert(rwflag == 0);    /* 0 -> callback used for decryption.
162                                  * See SSL_CTX_set_default_passwd_cb(3) */
163
164         passlen = (int) array_bytes(pass);
165
166         LogDebug("pem_passwd_cb buf size %d, array size %d", size, passlen);
167         assert(passlen >= 0);
168         if (passlen <= 0) {
169                 Log(LOG_ERR, "PEM password required but not set [in pem_passwd_cb()]!");
170                 return 0;
171         }
172         size = passlen > size ? size : passlen;
173         memcpy(buf, (char *)(array_start(pass)), size);
174         return size;
175 }
176
177
178 static int
179 Verify_openssl(UNUSED int preverify_ok, UNUSED X509_STORE_CTX *x509_ctx)
180 {
181         return 1;
182 }
183 #endif
184
185
186 static bool
187 Load_DH_params(void)
188 {
189 #ifdef HAVE_LIBSSL
190         FILE *fp;
191         bool ret = true;
192
193         if (!Conf_SSLOptions.DHFile) {
194                 Log(LOG_NOTICE, "Configuration option \"DHFile\" not set!");
195                 return false;
196         }
197         fp = fopen(Conf_SSLOptions.DHFile, "r");
198         if (!fp) {
199                 Log(LOG_ERR, "%s: %s", Conf_SSLOptions.DHFile, strerror(errno));
200                 return false;
201         }
202         dh_params = PEM_read_DHparams(fp, NULL, NULL, NULL);
203         if (!dh_params) {
204                 Log(LOG_ERR, "%s: Failed to read SSL DH parameters!",
205                     Conf_SSLOptions.DHFile);
206                 ret = false;
207         }
208         fclose(fp);
209         return ret;
210 #endif
211 #ifdef HAVE_LIBGNUTLS
212         bool need_dhgenerate = true;
213         int err;
214         gnutls_dh_params_t tmp_dh_params;
215
216         err = gnutls_dh_params_init(&tmp_dh_params);
217         if (err < 0) {
218                 Log(LOG_ERR, "Failed to initialize SSL DH parameters: %s",
219                     gnutls_strerror(err));
220                 return false;
221         }
222         if (Conf_SSLOptions.DHFile) {
223                 gnutls_datum_t dhparms;
224                 size_t size;
225                 dhparms.data = (unsigned char *) openreadclose(Conf_SSLOptions.DHFile, &size);
226                 if (dhparms.data) {
227                         dhparms.size = size;
228                         err = gnutls_dh_params_import_pkcs3(tmp_dh_params, &dhparms, GNUTLS_X509_FMT_PEM);
229                         if (err == 0)
230                                 need_dhgenerate = false;
231                         else
232                                 Log(LOG_ERR,
233                                     "Failed to initialize SSL DH parameters: %s",
234                                     gnutls_strerror(err));
235
236                         memset(dhparms.data, 0, size);
237                         free(dhparms.data);
238                 }
239         }
240         if (need_dhgenerate) {
241                 Log(LOG_WARNING,
242                     "DHFile not set, generating %u bit DH parameters. This may take a while ...",
243                     DH_BITS);
244                 err = gnutls_dh_params_generate2(tmp_dh_params, DH_BITS);
245                 if (err < 0) {
246                         Log(LOG_ERR, "Failed to generate SSL DH parameters: %s",
247                             gnutls_strerror(err));
248                         return false;
249                 }
250         }
251         dh_params = tmp_dh_params;
252         return true;
253 #endif
254 }
255
256
257 void ConnSSL_Free(CONNECTION *c)
258 {
259 #ifdef HAVE_LIBSSL
260         SSL *ssl = c->ssl_state.ssl;
261         if (ssl) {
262                 SSL_shutdown(ssl);
263                 SSL_free(ssl);
264                 c->ssl_state.ssl = NULL;
265                 if (c->ssl_state.fingerprint) {
266                         free(c->ssl_state.fingerprint);
267                         c->ssl_state.fingerprint = NULL;
268                 }
269         }
270 #endif
271 #ifdef HAVE_LIBGNUTLS
272         gnutls_session_t sess = c->ssl_state.gnutls_session;
273         if (Conn_OPTION_ISSET(c, CONN_SSL)) {
274                 gnutls_bye(sess, GNUTLS_SHUT_RDWR);
275                 gnutls_deinit(sess);
276         }
277         x509_cred_slot *slot = array_get(&x509_creds, sizeof(x509_cred_slot), c->ssl_state.x509_cred_idx);
278         assert(slot != NULL);
279         assert(slot->refcnt > 0);
280         assert(slot->x509_cred != NULL);
281         slot->refcnt--;
282         if ((c->ssl_state.x509_cred_idx != x509_cred_idx) && (slot->refcnt <= 0)) {
283                 Log(LOG_INFO, "Discarding X509 certificate credentials from slot %zd.",
284                     c->ssl_state.x509_cred_idx);
285                 gnutls_certificate_free_keys(slot->x509_cred);
286                 gnutls_certificate_free_credentials(slot->x509_cred);
287                 slot->x509_cred = NULL;
288                 gnutls_dh_params_deinit(slot->dh_params);
289                 slot->dh_params = NULL;
290                 slot->refcnt = 0;
291         }
292 #endif
293         assert(Conn_OPTION_ISSET(c, CONN_SSL));
294         /* can't just set bitmask to 0 -- there are other, non-ssl related flags, e.g. CONN_ZIP. */
295         Conn_OPTION_DEL(c, CONN_SSL_FLAGS_ALL);
296 }
297
298
299 bool
300 ConnSSL_InitLibrary( void )
301 {
302         if (!Conf_SSLInUse()) {
303                 LogDebug("SSL not in use, skipping initialization.");
304                 return true;
305         }
306
307 #ifdef HAVE_LIBSSL
308         SSL_CTX *newctx;
309
310 #if OPENSSL_API_COMPAT < 0x10100000L
311         if (!ssl_ctx) {
312                 SSL_library_init();
313                 SSL_load_error_strings();
314         }
315 #endif
316
317         if (!RAND_status()) {
318                 Log(LOG_ERR, "OpenSSL PRNG not seeded: /dev/urandom missing?");
319                 /*
320                  * it is probably best to fail and let the user install EGD or
321                  * a similar program if no kernel random device is available.
322                  * According to OpenSSL RAND_egd(3): "The automatic query of
323                  * /var/run/egd-pool et al was added in OpenSSL 0.9.7";
324                  * so it makes little sense to deal with PRNGD seeding ourselves.
325                  */
326                 array_free(&Conf_SSLOptions.ListenPorts);
327                 return false;
328         }
329
330         newctx = SSL_CTX_new(SSLv23_method());
331         if (!newctx) {
332                 LogOpenSSLError("Failed to create SSL context", NULL);
333                 array_free(&Conf_SSLOptions.ListenPorts);
334                 return false;
335         }
336
337         if (!ConnSSL_LoadServerKey_openssl(newctx)) {
338                 /* Failed to read new key but an old ssl context
339                  * already exists -> reuse old context */
340                 if (ssl_ctx) {
341                         SSL_CTX_free(newctx);
342                         Log(LOG_WARNING,
343                         "Re-Initializing of SSL failed, using old keys!");
344                         return true;
345                 }
346                 /* No preexisting old context -> error. */
347                 goto out;
348         }
349
350         if (SSL_CTX_set_cipher_list(newctx, Conf_SSLOptions.CipherList) == 0) {
351                 Log(LOG_ERR, "Failed to apply OpenSSL cipher list \"%s\"!",
352                     Conf_SSLOptions.CipherList);
353                 goto out;
354         }
355
356         SSL_CTX_set_session_id_context(newctx, (unsigned char *)"ngircd", 6);
357         SSL_CTX_set_options(newctx, SSL_OP_SINGLE_DH_USE|SSL_OP_NO_SSLv2);
358         SSL_CTX_set_mode(newctx, SSL_MODE_ENABLE_PARTIAL_WRITE);
359         SSL_CTX_set_verify(newctx, SSL_VERIFY_PEER|SSL_VERIFY_CLIENT_ONCE,
360                            Verify_openssl);
361         SSL_CTX_free(ssl_ctx);
362         ssl_ctx = newctx;
363         Log(LOG_INFO, "%s initialized.", OpenSSL_version(OPENSSL_VERSION));
364         return true;
365 out:
366         SSL_CTX_free(newctx);
367         array_free(&Conf_SSLOptions.ListenPorts);
368         return false;
369 #endif
370 #ifdef HAVE_LIBGNUTLS
371         int err;
372         static bool initialized;
373
374         if (!initialized) {
375                 err = gnutls_global_init();
376                 if (err) {
377                         Log(LOG_ERR, "Failed to initialize GnuTLS: %s",
378                             gnutls_strerror(err));
379                         goto out;
380                 }
381         }
382
383         if (!ConnSSL_LoadServerKey_gnutls())
384                 goto out;
385
386         if (priorities_cache != NULL) {
387                 gnutls_priority_deinit(priorities_cache);
388         }
389         if (gnutls_priority_init(&priorities_cache, Conf_SSLOptions.CipherList,
390                                  NULL) != GNUTLS_E_SUCCESS) {
391                 Log(LOG_ERR,
392                     "Failed to apply GnuTLS cipher list \"%s\"!",
393                     Conf_SSLOptions.CipherList);
394                 goto out;
395         }
396
397         Log(LOG_INFO, "GnuTLS %s initialized.", gnutls_check_version(NULL));
398         initialized = true;
399         return true;
400 out:
401         array_free(&Conf_SSLOptions.ListenPorts);
402         return false;
403 #endif
404 }
405
406
407 #ifdef HAVE_LIBGNUTLS
408 static bool
409 ConnSSL_LoadServerKey_gnutls(void)
410 {
411         int err;
412         const char *cert_file;
413
414         x509_cred_slot *slot = NULL;
415         gnutls_certificate_credentials_t x509_cred;
416
417         err = gnutls_certificate_allocate_credentials(&x509_cred);
418         if (err < 0) {
419                 Log(LOG_ERR, "Failed to allocate certificate credentials: %s",
420                     gnutls_strerror(err));
421                 return false;
422         }
423
424         cert_file = Conf_SSLOptions.CertFile ? Conf_SSLOptions.CertFile:Conf_SSLOptions.KeyFile;
425         if (!cert_file) {
426                 Log(LOG_ERR, "No SSL server key configured!");
427                 return false;
428         }
429
430         if (array_bytes(&Conf_SSLOptions.KeyFilePassword))
431                 Log(LOG_WARNING,
432                     "Ignoring SSL \"KeyFilePassword\": Not supported by GnuTLS.");
433
434         if (!Load_DH_params())
435                 return false;
436
437         gnutls_certificate_set_dh_params(x509_cred, dh_params);
438         err = gnutls_certificate_set_x509_key_file(x509_cred, cert_file, Conf_SSLOptions.KeyFile, GNUTLS_X509_FMT_PEM);
439         if (err < 0) {
440                 Log(LOG_ERR,
441                     "Failed to set certificate key file (cert %s, key %s): %s",
442                     cert_file,
443                     Conf_SSLOptions.KeyFile ? Conf_SSLOptions.KeyFile : "(NULL)",
444                     gnutls_strerror(err));
445                 return false;
446         }
447
448         /* Free currently active x509 context (if any) unless it is still in use */
449         slot = array_get(&x509_creds, sizeof(x509_cred_slot), x509_cred_idx);
450         if ((slot != NULL) && (slot->refcnt <= 0) && (slot->x509_cred != NULL)) {
451                 Log(LOG_INFO, "Discarding X509 certificate credentials from slot %zd.", x509_cred_idx);
452                 gnutls_certificate_free_keys(slot->x509_cred);
453                 gnutls_certificate_free_credentials(slot->x509_cred);
454                 slot->x509_cred = NULL;
455                 gnutls_dh_params_deinit(slot->dh_params);
456                 slot->dh_params = NULL;
457                 slot->refcnt = 0;
458         }
459
460         /* Find free slot */
461         x509_cred_idx = (size_t) -1;
462         size_t i;
463         for (slot = array_start(&x509_creds), i = 0;
464              i < array_length(&x509_creds, sizeof(x509_cred_slot));
465              slot++, i++) {
466                 if (slot->refcnt <= 0) {
467                         x509_cred_idx = i;
468                         break;
469                 }
470         }
471         /* ... allocate new slot otherwise. */
472         if (x509_cred_idx == (size_t) -1) {
473                 x509_cred_idx = array_length(&x509_creds, sizeof(x509_cred_slot));
474                 slot = array_alloc(&x509_creds, sizeof(x509_cred_slot), x509_cred_idx);
475                 if (slot == NULL) {
476                         Log(LOG_ERR, "Failed to allocate new slot for certificate credentials");
477                         return false;
478                 }
479         }
480         Log(LOG_INFO, "Storing new X509 certificate credentials in slot %zd.", x509_cred_idx);
481         slot->x509_cred = x509_cred;
482         slot->refcnt = 0;
483
484         return true;
485 }
486 #endif
487
488
489 #ifdef HAVE_LIBSSL
490 static bool
491 ConnSSL_LoadServerKey_openssl(SSL_CTX *ctx)
492 {
493         char *cert_key;
494
495         assert(ctx);
496         if (!Conf_SSLOptions.KeyFile) {
497                 Log(LOG_ERR, "No SSL server key configured!");
498                 return false;
499         }
500
501         SSL_CTX_set_default_passwd_cb(ctx, pem_passwd_cb);
502         SSL_CTX_set_default_passwd_cb_userdata(ctx, &Conf_SSLOptions.KeyFilePassword);
503
504         if (SSL_CTX_use_PrivateKey_file(ctx, Conf_SSLOptions.KeyFile, SSL_FILETYPE_PEM) != 1) {
505                 array_free_wipe(&Conf_SSLOptions.KeyFilePassword);
506                 LogOpenSSLError("Failed to add private key", Conf_SSLOptions.KeyFile);
507                 return false;
508         }
509
510         cert_key = Conf_SSLOptions.CertFile ? Conf_SSLOptions.CertFile:Conf_SSLOptions.KeyFile;
511         if (SSL_CTX_use_certificate_chain_file(ctx, cert_key) != 1) {
512                 array_free_wipe(&Conf_SSLOptions.KeyFilePassword);
513                 LogOpenSSLError("Failed to load certificate chain", cert_key);
514                 return false;
515         }
516
517         array_free_wipe(&Conf_SSLOptions.KeyFilePassword);
518
519         if (!SSL_CTX_check_private_key(ctx)) {
520                 LogOpenSSLError("Server private key does not match certificate", NULL);
521                 return false;
522         }
523         if (Load_DH_params()) {
524                 if (SSL_CTX_set_tmp_dh(ctx, dh_params) != 1)
525                         LogOpenSSLError("Error setting DH parameters", Conf_SSLOptions.DHFile);
526                 /* don't return false here: the non-DH modes will still work */
527                 DH_free(dh_params);
528                 dh_params = NULL;
529         }
530         return true;
531 }
532
533
534 #endif
535 static bool
536 ConnSSL_Init_SSL(CONNECTION *c)
537 {
538         int ret;
539
540         LogDebug("Initializing SSL ...");
541         assert(c != NULL);
542
543 #ifdef HAVE_LIBSSL
544         if (!ssl_ctx) {
545                 Log(LOG_ERR,
546                     "Can't initialize SSL context, OpenSSL initialization failed at startup!");
547                 return false;
548         }
549         assert(c->ssl_state.ssl == NULL);
550         assert(c->ssl_state.fingerprint == NULL);
551
552         c->ssl_state.ssl = SSL_new(ssl_ctx);
553         if (!c->ssl_state.ssl) {
554                 LogOpenSSLError("Failed to create SSL structure", NULL);
555                 return false;
556         }
557         Conn_OPTION_ADD(c, CONN_SSL);
558
559         ret = SSL_set_fd(c->ssl_state.ssl, c->sock);
560         if (ret != 1) {
561                 LogOpenSSLError("Failed to set SSL file descriptor", NULL);
562                 ConnSSL_Free(c);
563                 return false;
564         }
565 #endif
566 #ifdef HAVE_LIBGNUTLS
567         Conn_OPTION_ADD(c, CONN_SSL);
568         ret = gnutls_priority_set(c->ssl_state.gnutls_session, priorities_cache);
569         if (ret != GNUTLS_E_SUCCESS) {
570                 Log(LOG_ERR, "Failed to set GnuTLS session priorities: %s",
571                     gnutls_strerror(ret));
572                 ConnSSL_Free(c);
573                 return false;
574         }
575         /*
576          * The intermediate (long) cast is here to avoid a warning like:
577          * "cast to pointer from integer of different size" on 64-bit platforms.
578          * There doesn't seem to be an alternate GNUTLS API we could use instead, see e.g.
579          * http://www.mail-archive.com/help-gnutls@gnu.org/msg00286.html
580          */
581         gnutls_transport_set_ptr(c->ssl_state.gnutls_session,
582                                  (gnutls_transport_ptr_t) (long) c->sock);
583         gnutls_certificate_server_set_request(c->ssl_state.gnutls_session,
584                                               GNUTLS_CERT_REQUEST);
585
586         Log(LOG_INFO, "Using X509 credentials from slot %zd", x509_cred_idx);
587         c->ssl_state.x509_cred_idx = x509_cred_idx;
588         x509_cred_slot *slot = array_get(&x509_creds, sizeof(x509_cred_slot), x509_cred_idx);
589         slot->refcnt++;
590         ret = gnutls_credentials_set(c->ssl_state.gnutls_session,
591                                      GNUTLS_CRD_CERTIFICATE, slot->x509_cred);
592         if (ret != 0) {
593                 Log(LOG_ERR, "Failed to set SSL credentials: %s",
594                     gnutls_strerror(ret));
595                 ConnSSL_Free(c);
596                 return false;
597         }
598         gnutls_dh_set_prime_bits(c->ssl_state.gnutls_session, DH_BITS_MIN);
599 #endif
600         return true;
601 }
602
603
604 bool
605 ConnSSL_PrepareConnect(CONNECTION *c, UNUSED CONF_SERVER *s)
606 {
607         bool ret;
608 #ifdef HAVE_LIBGNUTLS
609         int err;
610
611         err = gnutls_init(&c->ssl_state.gnutls_session, GNUTLS_CLIENT);
612         if (err) {
613                 Log(LOG_ERR, "Failed to initialize new SSL session: %s",
614                     gnutls_strerror(err));
615                 return false;
616         }
617 #endif
618         ret = ConnSSL_Init_SSL(c);
619         if (!ret)
620                 return false;
621         Conn_OPTION_ADD(c, CONN_SSL_CONNECT);
622 #ifdef HAVE_LIBSSL
623         assert(c->ssl_state.ssl);
624         SSL_set_verify(c->ssl_state.ssl, SSL_VERIFY_NONE, NULL);
625 #endif
626         return true;
627 }
628
629
630 /**
631  * Check and handle error return codes after failed calls to SSL functions.
632  *
633  * OpenSSL:
634  * SSL_connect(), SSL_accept(), SSL_do_handshake(), SSL_read(), SSL_peek(), or
635  * SSL_write() on ssl.
636  *
637  * GnuTLS:
638  * gnutlsssl_read(), gnutls_write() or gnutls_handshake().
639  *
640  * @param c The connection handle.
641  * @prarm code The return code.
642  * @param fname The name of the function in which the error occurred.
643  * @return -1 on fatal errors, 0 if we can try again later.
644  */
645 static int
646 ConnSSL_HandleError(CONNECTION * c, const int code, const char *fname)
647 {
648 #ifdef HAVE_LIBSSL
649         int ret = SSL_ERROR_SYSCALL;
650         unsigned long sslerr;
651         int real_errno = errno;
652
653         ret = SSL_get_error(c->ssl_state.ssl, code);
654
655         switch (ret) {
656         case SSL_ERROR_WANT_READ:
657                 io_event_del(c->sock, IO_WANTWRITE);
658                 Conn_OPTION_ADD(c, CONN_SSL_WANT_READ);
659                 return 0;       /* try again later */
660         case SSL_ERROR_WANT_WRITE:
661                 io_event_del(c->sock, IO_WANTREAD);
662                 Conn_OPTION_ADD(c, CONN_SSL_WANT_WRITE); /* fall through */
663         case SSL_ERROR_NONE:
664                 return 0;       /* try again later */
665         case SSL_ERROR_ZERO_RETURN:
666                 LogDebug("SSL connection shut down normally.");
667                 break;
668         case SSL_ERROR_SYSCALL:
669                 /* SSL_ERROR_WANT_CONNECT, SSL_ERROR_WANT_ACCEPT,
670                  * and SSL_ERROR_WANT_X509_LOOKUP */
671                 sslerr = ERR_get_error();
672                 if (sslerr) {
673                         Log(LOG_ERR, "SSL error: %s [in %s()]!",
674                             ERR_error_string(sslerr, NULL), fname);
675                 } else {
676                         switch (code) { /* EOF that violated protocol */
677                         case 0:
678                                 Log(LOG_ERR,
679                                     "SSL error, client disconnected [in %s()]!",
680                                     fname);
681                                 break;
682                         case -1:        /* low level socket I/O error, check errno */
683                                 Log(LOG_ERR, "SSL error: %s [in %s()]!",
684                                     strerror(real_errno), fname);
685                         }
686                 }
687                 break;
688         case SSL_ERROR_SSL:
689                 LogOpenSSLError("SSL protocol error", fname);
690                 break;
691         default:
692                 Log(LOG_ERR, "Unknown SSL error %d [in %s()]!", ret, fname);
693         }
694         ConnSSL_Free(c);
695         return -1;
696 #endif
697 #ifdef HAVE_LIBGNUTLS
698         switch (code) {
699         case GNUTLS_E_AGAIN:
700         case GNUTLS_E_INTERRUPTED:
701                 if (gnutls_record_get_direction(c->ssl_state.gnutls_session)) {
702                         Conn_OPTION_ADD(c, CONN_SSL_WANT_WRITE);
703                         io_event_del(c->sock, IO_WANTREAD);
704                 } else {
705                         Conn_OPTION_ADD(c, CONN_SSL_WANT_READ);
706                         io_event_del(c->sock, IO_WANTWRITE);
707                 }
708                 break;
709         default:
710                 assert(code < 0);
711                 if (gnutls_error_is_fatal(code)) {
712                         Log(LOG_ERR, "SSL error: %s [%s].",
713                             gnutls_strerror(code), fname);
714                         ConnSSL_Free(c);
715                         return -1;
716                 }
717         }
718         return 0;
719 #endif
720 }
721
722
723 static void
724 ConnSSL_LogCertInfo( CONNECTION *c )
725 {
726 #ifdef HAVE_LIBSSL
727         SSL *ssl = c->ssl_state.ssl;
728
729         assert(ssl);
730
731         Log(LOG_INFO, "Connection %d: initialized %s using cipher %s.",
732                 c->sock, SSL_get_version(ssl), SSL_get_cipher(ssl));
733 #endif
734 #ifdef HAVE_LIBGNUTLS
735         gnutls_session_t sess = c->ssl_state.gnutls_session;
736         gnutls_cipher_algorithm_t cipher = gnutls_cipher_get(sess);
737
738         Log(LOG_INFO, "Connection %d: initialized %s using cipher %s-%s.",
739             c->sock,
740             gnutls_protocol_get_name(gnutls_protocol_get_version(sess)),
741             gnutls_cipher_get_name(cipher),
742             gnutls_mac_get_name(gnutls_mac_get(sess)));
743 #endif
744 }
745
746
747 /*
748  Accept incoming SSL connection.
749  Return Values:
750          1: SSL Connection established
751          0: try again
752         -1: SSL Connection not established due to fatal error.
753 */
754 int
755 ConnSSL_Accept( CONNECTION *c )
756 {
757         assert(c != NULL);
758         if (!Conn_OPTION_ISSET(c, CONN_SSL)) {
759 #ifdef HAVE_LIBGNUTLS
760                 int err = gnutls_init(&c->ssl_state.gnutls_session, GNUTLS_SERVER);
761                 if (err) {
762                         Log(LOG_ERR, "Failed to initialize new SSL session: %s",
763                             gnutls_strerror(err));
764                         return false;
765                 }
766 #endif
767                 if (!ConnSSL_Init_SSL(c))
768                         return -1;
769         }
770         return ConnectAccept(c, false );
771 }
772
773
774 int
775 ConnSSL_Connect( CONNECTION *c )
776 {
777         assert(c != NULL);
778 #ifdef HAVE_LIBSSL
779         assert(c->ssl_state.ssl);
780 #endif
781         assert(Conn_OPTION_ISSET(c, CONN_SSL));
782         return ConnectAccept(c, true);
783 }
784
785 static int
786 ConnSSL_InitCertFp( CONNECTION *c )
787 {
788         const char hex[] = "0123456789abcdef";
789         int i;
790
791 #ifdef HAVE_LIBSSL
792         unsigned char digest[EVP_MAX_MD_SIZE];
793         unsigned int digest_size;
794         X509 *cert;
795
796         cert = SSL_get_peer_certificate(c->ssl_state.ssl);
797         if (!cert)
798                 return 0;
799
800         if (!X509_digest(cert, EVP_sha256(), digest, &digest_size)) {
801                 X509_free(cert);
802                 return 0;
803         }
804
805         X509_free(cert);
806 #endif /* HAVE_LIBSSL */
807 #ifdef HAVE_LIBGNUTLS
808         gnutls_x509_crt_t cert;
809         unsigned int cert_list_size;
810         const gnutls_datum_t *cert_list;
811         unsigned char digest[MAX_HASH_SIZE];
812         size_t digest_size;
813
814         if (gnutls_certificate_type_get(c->ssl_state.gnutls_session) !=
815                                         GNUTLS_CRT_X509)
816                 return 0;
817
818         if (gnutls_x509_crt_init(&cert) != GNUTLS_E_SUCCESS)
819                 return 0;
820
821         cert_list_size = 0;
822         cert_list = gnutls_certificate_get_peers(c->ssl_state.gnutls_session,
823                                                  &cert_list_size);
824         if (!cert_list) {
825                 gnutls_x509_crt_deinit(cert);
826                 return 0;
827         }
828
829         if (gnutls_x509_crt_import(cert, &cert_list[0],
830                                    GNUTLS_X509_FMT_DER) != GNUTLS_E_SUCCESS) {
831                 gnutls_x509_crt_deinit(cert);
832                 return 0;
833         }
834
835         digest_size = sizeof(digest);
836         if (gnutls_x509_crt_get_fingerprint(cert, GNUTLS_DIG_SHA256, digest,
837                                             &digest_size)) {
838                 gnutls_x509_crt_deinit(cert);
839                 return 0;
840         }
841
842         gnutls_x509_crt_deinit(cert);
843 #endif /* HAVE_LIBGNUTLS */
844
845         assert(c->ssl_state.fingerprint == NULL);
846
847         c->ssl_state.fingerprint = malloc(SHA256_STRING_LEN);
848         if (!c->ssl_state.fingerprint)
849                 return 0;
850
851         for (i = 0; i < (int)digest_size; i++) {
852                 c->ssl_state.fingerprint[i * 2] = hex[digest[i] / 16];
853                 c->ssl_state.fingerprint[i * 2 + 1] = hex[digest[i] % 16];
854         }
855         c->ssl_state.fingerprint[i * 2] = '\0';
856
857         return 1;
858 }
859
860 /* accept/connect wrapper. if connect is true, connect to peer, otherwise wait for incoming connection */
861 static int
862 ConnectAccept( CONNECTION *c, bool connect)
863 {
864         int ret;
865 #ifdef HAVE_LIBSSL
866         SSL *ssl = c->ssl_state.ssl;
867         assert(ssl != NULL);
868
869         ret = connect ? SSL_connect(ssl) : SSL_accept(ssl);
870         if (1 != ret)
871                 return ConnSSL_HandleError(c, ret, connect ? "SSL_connect": "SSL_accept");
872 #endif
873 #ifdef HAVE_LIBGNUTLS
874         (void) connect;
875         ret = gnutls_handshake(c->ssl_state.gnutls_session);
876         if (ret)
877                 return ConnSSL_HandleError(c, ret, "gnutls_handshake");
878 #endif /* _GNUTLS */
879         (void)ConnSSL_InitCertFp(c);
880
881         Conn_OPTION_DEL(c, (CONN_SSL_WANT_WRITE|CONN_SSL_WANT_READ|CONN_SSL_CONNECT));
882         ConnSSL_LogCertInfo(c);
883
884         Conn_StartLogin(CONNECTION2ID(c));
885         return 1;
886 }
887
888
889 ssize_t
890 ConnSSL_Write(CONNECTION *c, const void *buf, size_t count)
891 {
892         ssize_t bw;
893
894         Conn_OPTION_DEL(c, CONN_SSL_WANT_WRITE|CONN_SSL_WANT_READ);
895
896         assert(count > 0);
897 #ifdef HAVE_LIBSSL
898         bw = (ssize_t) SSL_write(c->ssl_state.ssl, buf, count);
899 #endif
900 #ifdef HAVE_LIBGNUTLS
901         bw = gnutls_write(c->ssl_state.gnutls_session, buf, count);
902 #endif
903         if (bw > 0)
904                 return bw;
905         if (ConnSSL_HandleError( c, bw, "ConnSSL_Write") == 0)
906                 errno = EAGAIN; /* try again */
907         return -1;
908 }
909
910
911 ssize_t
912 ConnSSL_Read(CONNECTION *c, void * buf, size_t count)
913 {
914         ssize_t br;
915
916         Conn_OPTION_DEL(c, CONN_SSL_WANT_WRITE|CONN_SSL_WANT_READ);
917 #ifdef HAVE_LIBSSL
918         br = (ssize_t) SSL_read(c->ssl_state.ssl, buf, count);
919         if (br > 0)     /* on EOF we have to call ConnSSL_HandleError(), see SSL_read(3) */
920                 return br;
921 #endif
922 #ifdef HAVE_LIBGNUTLS
923         br = gnutls_read(c->ssl_state.gnutls_session, buf, count);
924         if (br >= 0)    /* on EOF we must _not_ call ConnSSL_HandleError, see gnutls_record_recv(3) */
925                 return br;
926 #endif
927         /* error on read: switch ConnSSL_HandleError() return values -> 0 is "try again", so return -1 and set EAGAIN */
928         if (ConnSSL_HandleError(c, br, "ConnSSL_Read") == 0) {
929                 errno = EAGAIN;
930                 return -1;
931         }
932         return 0;
933 }
934
935
936 bool
937 ConnSSL_GetCipherInfo(CONNECTION *c, char *buf, size_t len)
938 {
939 #ifdef HAVE_LIBSSL
940         char *nl;
941         SSL *ssl = c->ssl_state.ssl;
942
943         if (!ssl)
944                 return false;
945         *buf = 0;
946         SSL_CIPHER_description(SSL_get_current_cipher(ssl), buf, len);
947         nl = strchr(buf, '\n');
948         if (nl)
949                 *nl = 0;
950         return true;
951 #endif
952 #ifdef HAVE_LIBGNUTLS
953         if (Conn_OPTION_ISSET(c, CONN_SSL)) {
954                 const char *name_cipher, *name_mac, *name_proto, *name_keyexchange;
955                 unsigned keysize;
956
957                 gnutls_session_t sess = c->ssl_state.gnutls_session;
958                 gnutls_cipher_algorithm_t cipher = gnutls_cipher_get(sess);
959                 name_cipher = gnutls_cipher_get_name(cipher);
960                 name_mac = gnutls_mac_get_name(gnutls_mac_get(sess));
961                 keysize = gnutls_cipher_get_key_size(cipher) * 8;
962                 name_proto = gnutls_protocol_get_name(gnutls_protocol_get_version(sess));
963                 name_keyexchange = gnutls_kx_get_name(gnutls_kx_get(sess));
964
965                 return snprintf(buf, len, "%s-%s%15s Kx=%s      Enc=%s(%u) Mac=%s",
966                         name_cipher, name_mac, name_proto, name_keyexchange, name_cipher, keysize, name_mac) > 0;
967         }
968         return false;
969 #endif
970 }
971
972 char *
973 ConnSSL_GetCertFp(CONNECTION *c)
974 {
975         return c->ssl_state.fingerprint;
976 }
977
978 bool
979 ConnSSL_SetCertFp(CONNECTION *c, const char *fingerprint)
980 {
981         assert (c != NULL);
982         c->ssl_state.fingerprint = strndup(fingerprint, SHA256_STRING_LEN - 1);
983         return c->ssl_state.fingerprint != NULL;
984 }
985 #else
986
987 bool
988 ConnSSL_InitLibrary(void)
989 {
990         return true;
991 }
992
993 #endif /* SSL_SUPPORT */
994 /* -eof- */