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                 LogDebug("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                 LogDebug("Discarding X509 certificate credentials from slot %zd.",
 452                          x509_cred_idx);
 453                 gnutls_certificate_free_keys(slot->x509_cred);
 454                 gnutls_certificate_free_credentials(slot->x509_cred);
 455                 slot->x509_cred = NULL;
 456                 gnutls_dh_params_deinit(slot->dh_params);
 457                 slot->dh_params = NULL;
 458                 slot->refcnt = 0;
 459         }
 460
 461         /* Find free slot */
 462         x509_cred_idx = (size_t) -1;
 463         size_t i;
 464         for (slot = array_start(&x509_creds), i = 0;
 465              i < array_length(&x509_creds, sizeof(x509_cred_slot));
 466              slot++, i++) {
 467                 if (slot->refcnt <= 0) {
 468                         x509_cred_idx = i;
 469                         break;
 470                 }
 471         }
 472         /* ... allocate new slot otherwise. */
 473         if (x509_cred_idx == (size_t) -1) {
 474                 x509_cred_idx = array_length(&x509_creds, sizeof(x509_cred_slot));
 475                 slot = array_alloc(&x509_creds, sizeof(x509_cred_slot), x509_cred_idx);
 476                 if (slot == NULL) {
 477                         Log(LOG_ERR, "Failed to allocate new slot for certificate credentials");
 478                         return false;
 479                 }
 480         }
 481         Log(LOG_INFO, "Storing new X509 certificate credentials in slot %zd.", x509_cred_idx);
 482         slot->x509_cred = x509_cred;
 483         slot->refcnt = 0;
 484
 485         return true;
 486 }
 487 #endif
 488
 489
 490 #ifdef HAVE_LIBSSL
 491 static bool
 492 ConnSSL_LoadServerKey_openssl(SSL_CTX *ctx)
 493 {
 494         char *cert_key;
 495
 496         assert(ctx);
 497         if (!Conf_SSLOptions.KeyFile) {
 498                 Log(LOG_ERR, "No SSL server key configured!");
 499                 return false;
 500         }
 501
 502         SSL_CTX_set_default_passwd_cb(ctx, pem_passwd_cb);
 503         SSL_CTX_set_default_passwd_cb_userdata(ctx, &Conf_SSLOptions.KeyFilePassword);
 504
 505         if (SSL_CTX_use_PrivateKey_file(ctx, Conf_SSLOptions.KeyFile, SSL_FILETYPE_PEM) != 1) {
 506                 array_free_wipe(&Conf_SSLOptions.KeyFilePassword);
 507                 LogOpenSSLError("Failed to add private key", Conf_SSLOptions.KeyFile);
 508                 return false;
 509         }
 510
 511         cert_key = Conf_SSLOptions.CertFile ? Conf_SSLOptions.CertFile:Conf_SSLOptions.KeyFile;
 512         if (SSL_CTX_use_certificate_chain_file(ctx, cert_key) != 1) {
 513                 array_free_wipe(&Conf_SSLOptions.KeyFilePassword);
 514                 LogOpenSSLError("Failed to load certificate chain", cert_key);
 515                 return false;
 516         }
 517
 518         array_free_wipe(&Conf_SSLOptions.KeyFilePassword);
 519
 520         if (!SSL_CTX_check_private_key(ctx)) {
 521                 LogOpenSSLError("Server private key does not match certificate", NULL);
 522                 return false;
 523         }
 524         if (Load_DH_params()) {
 525                 if (SSL_CTX_set_tmp_dh(ctx, dh_params) != 1)
 526                         LogOpenSSLError("Error setting DH parameters", Conf_SSLOptions.DHFile);
 527                 /* don't return false here: the non-DH modes will still work */
 528                 DH_free(dh_params);
 529                 dh_params = NULL;
 530         }
 531         return true;
 532 }
 533
 534
 535 #endif
 536 static bool
 537 ConnSSL_Init_SSL(CONNECTION *c)
 538 {
 539         int ret;
 540
 541         LogDebug("Initializing SSL ...");
 542         assert(c != NULL);
 543
 544 #ifdef HAVE_LIBSSL
 545         if (!ssl_ctx) {
 546                 Log(LOG_ERR,
 547                     "Can't initialize SSL context, OpenSSL initialization failed at startup!");
 548                 return false;
 549         }
 550         assert(c->ssl_state.ssl == NULL);
 551         assert(c->ssl_state.fingerprint == NULL);
 552
 553         c->ssl_state.ssl = SSL_new(ssl_ctx);
 554         if (!c->ssl_state.ssl) {
 555                 LogOpenSSLError("Failed to create SSL structure", NULL);
 556                 return false;
 557         }
 558         Conn_OPTION_ADD(c, CONN_SSL);
 559
 560         ret = SSL_set_fd(c->ssl_state.ssl, c->sock);
 561         if (ret != 1) {
 562                 LogOpenSSLError("Failed to set SSL file descriptor", NULL);
 563                 ConnSSL_Free(c);
 564                 return false;
 565         }
 566 #endif
 567 #ifdef HAVE_LIBGNUTLS
 568         Conn_OPTION_ADD(c, CONN_SSL);
 569         ret = gnutls_priority_set(c->ssl_state.gnutls_session, priorities_cache);
 570         if (ret != GNUTLS_E_SUCCESS) {
 571                 Log(LOG_ERR, "Failed to set GnuTLS session priorities: %s",
 572                     gnutls_strerror(ret));
 573                 ConnSSL_Free(c);
 574                 return false;
 575         }
 576         /*
 577          * The intermediate (long) cast is here to avoid a warning like:
 578          * "cast to pointer from integer of different size" on 64-bit platforms.
 579          * There doesn't seem to be an alternate GNUTLS API we could use instead, see e.g.
 580          * http://www.mail-archive.com/help-gnutls@gnu.org/msg00286.html
 581          */
 582         gnutls_transport_set_ptr(c->ssl_state.gnutls_session,
 583                                  (gnutls_transport_ptr_t) (long) c->sock);
 584         gnutls_certificate_server_set_request(c->ssl_state.gnutls_session,
 585                                               GNUTLS_CERT_REQUEST);
 586
 587         LogDebug("Using X509 credentials from slot %zd.", x509_cred_idx);
 588         c->ssl_state.x509_cred_idx = x509_cred_idx;
 589         x509_cred_slot *slot = array_get(&x509_creds, sizeof(x509_cred_slot), x509_cred_idx);
 590         slot->refcnt++;
 591         ret = gnutls_credentials_set(c->ssl_state.gnutls_session,
 592                                      GNUTLS_CRD_CERTIFICATE, slot->x509_cred);
 593         if (ret != 0) {
 594                 Log(LOG_ERR, "Failed to set SSL credentials: %s",
 595                     gnutls_strerror(ret));
 596                 ConnSSL_Free(c);
 597                 return false;
 598         }
 599         gnutls_dh_set_prime_bits(c->ssl_state.gnutls_session, DH_BITS_MIN);
 600 #endif
 601         return true;
 602 }
 603
 604
 605 bool
 606 ConnSSL_PrepareConnect(CONNECTION *c, UNUSED CONF_SERVER *s)
 607 {
 608         bool ret;
 609 #ifdef HAVE_LIBGNUTLS
 610         int err;
 611
 612         err = gnutls_init(&c->ssl_state.gnutls_session, GNUTLS_CLIENT);
 613         if (err) {
 614                 Log(LOG_ERR, "Failed to initialize new SSL session: %s",
 615                     gnutls_strerror(err));
 616                 return false;
 617         }
 618 #endif
 619         ret = ConnSSL_Init_SSL(c);
 620         if (!ret)
 621                 return false;
 622         Conn_OPTION_ADD(c, CONN_SSL_CONNECT);
 623 #ifdef HAVE_LIBSSL
 624         assert(c->ssl_state.ssl);
 625         SSL_set_verify(c->ssl_state.ssl, SSL_VERIFY_NONE, NULL);
 626 #endif
 627         return true;
 628 }
 629
 630
 631 /**
 632  * Check and handle error return codes after failed calls to SSL functions.
 633  *
 634  * OpenSSL:
 635  * SSL_connect(), SSL_accept(), SSL_do_handshake(), SSL_read(), SSL_peek(), or
 636  * SSL_write() on ssl.
 637  *
 638  * GnuTLS:
 639  * gnutlsssl_read(), gnutls_write() or gnutls_handshake().
 640  *
 641  * @param c The connection handle.
 642  * @prarm code The return code.
 643  * @param fname The name of the function in which the error occurred.
 644  * @return -1 on fatal errors, 0 if we can try again later.
 645  */
 646 static int
 647 ConnSSL_HandleError(CONNECTION * c, const int code, const char *fname)
 648 {
 649 #ifdef HAVE_LIBSSL
 650         int ret = SSL_ERROR_SYSCALL;
 651         unsigned long sslerr;
 652         int real_errno = errno;
 653
 654         ret = SSL_get_error(c->ssl_state.ssl, code);
 655
 656         switch (ret) {
 657         case SSL_ERROR_WANT_READ:
 658                 io_event_del(c->sock, IO_WANTWRITE);
 659                 Conn_OPTION_ADD(c, CONN_SSL_WANT_READ);
 660                 return 0;       /* try again later */
 661         case SSL_ERROR_WANT_WRITE:
 662                 io_event_del(c->sock, IO_WANTREAD);
 663                 Conn_OPTION_ADD(c, CONN_SSL_WANT_WRITE); /* fall through */
 664         case SSL_ERROR_NONE:
 665                 return 0;       /* try again later */
 666         case SSL_ERROR_ZERO_RETURN:
 667                 LogDebug("SSL connection shut down normally.");
 668                 break;
 669         case SSL_ERROR_SYSCALL:
 670                 /* SSL_ERROR_WANT_CONNECT, SSL_ERROR_WANT_ACCEPT,
 671                  * and SSL_ERROR_WANT_X509_LOOKUP */
 672                 sslerr = ERR_get_error();
 673                 if (sslerr) {
 674                         Log(LOG_ERR, "SSL error: %s [in %s()]!",
 675                             ERR_error_string(sslerr, NULL), fname);
 676                 } else {
 677                         switch (code) { /* EOF that violated protocol */
 678                         case 0:
 679                                 Log(LOG_ERR,
 680                                     "SSL error, client disconnected [in %s()]!",
 681                                     fname);
 682                                 break;
 683                         case -1:        /* low level socket I/O error, check errno */
 684                                 Log(LOG_ERR, "SSL error: %s [in %s()]!",
 685                                     strerror(real_errno), fname);
 686                         }
 687                 }
 688                 break;
 689         case SSL_ERROR_SSL:
 690                 LogOpenSSLError("SSL protocol error", fname);
 691                 break;
 692         default:
 693                 Log(LOG_ERR, "Unknown SSL error %d [in %s()]!", ret, fname);
 694         }
 695         ConnSSL_Free(c);
 696         return -1;
 697 #endif
 698 #ifdef HAVE_LIBGNUTLS
 699         switch (code) {
 700         case GNUTLS_E_AGAIN:
 701         case GNUTLS_E_INTERRUPTED:
 702                 if (gnutls_record_get_direction(c->ssl_state.gnutls_session)) {
 703                         Conn_OPTION_ADD(c, CONN_SSL_WANT_WRITE);
 704                         io_event_del(c->sock, IO_WANTREAD);
 705                 } else {
 706                         Conn_OPTION_ADD(c, CONN_SSL_WANT_READ);
 707                         io_event_del(c->sock, IO_WANTWRITE);
 708                 }
 709                 break;
 710         default:
 711                 assert(code < 0);
 712                 if (gnutls_error_is_fatal(code)) {
 713                         Log(LOG_ERR, "SSL error: %s [%s].",
 714                             gnutls_strerror(code), fname);
 715                         ConnSSL_Free(c);
 716                         return -1;
 717                 }
 718         }
 719         return 0;
 720 #endif
 721 }
 722
 723
 724 static void
 725 ConnSSL_LogCertInfo( CONNECTION *c )
 726 {
 727 #ifdef HAVE_LIBSSL
 728         SSL *ssl = c->ssl_state.ssl;
 729
 730         assert(ssl);
 731
 732         Log(LOG_INFO, "Connection %d: initialized %s using cipher %s.",
 733                 c->sock, SSL_get_version(ssl), SSL_get_cipher(ssl));
 734 #endif
 735 #ifdef HAVE_LIBGNUTLS
 736         gnutls_session_t sess = c->ssl_state.gnutls_session;
 737         gnutls_cipher_algorithm_t cipher = gnutls_cipher_get(sess);
 738
 739         Log(LOG_INFO, "Connection %d: initialized %s using cipher %s-%s.",
 740             c->sock,
 741             gnutls_protocol_get_name(gnutls_protocol_get_version(sess)),
 742             gnutls_cipher_get_name(cipher),
 743             gnutls_mac_get_name(gnutls_mac_get(sess)));
 744 #endif
 745 }
 746
 747
 748 /*
 749  Accept incoming SSL connection.
 750  Return Values:
 751          1: SSL Connection established
 752          0: try again
 753         -1: SSL Connection not established due to fatal error.
 754 */
 755 int
 756 ConnSSL_Accept( CONNECTION *c )
 757 {
 758         assert(c != NULL);
 759         if (!Conn_OPTION_ISSET(c, CONN_SSL)) {
 760 #ifdef HAVE_LIBGNUTLS
 761                 int err = gnutls_init(&c->ssl_state.gnutls_session, GNUTLS_SERVER);
 762                 if (err) {
 763                         Log(LOG_ERR, "Failed to initialize new SSL session: %s",
 764                             gnutls_strerror(err));
 765                         return false;
 766                 }
 767 #endif
 768                 if (!ConnSSL_Init_SSL(c))
 769                         return -1;
 770         }
 771         return ConnectAccept(c, false );
 772 }
 773
 774
 775 int
 776 ConnSSL_Connect( CONNECTION *c )
 777 {
 778         assert(c != NULL);
 779 #ifdef HAVE_LIBSSL
 780         assert(c->ssl_state.ssl);
 781 #endif
 782         assert(Conn_OPTION_ISSET(c, CONN_SSL));
 783         return ConnectAccept(c, true);
 784 }
 785
 786 static int
 787 ConnSSL_InitCertFp( CONNECTION *c )
 788 {
 789         const char hex[] = "0123456789abcdef";
 790         int i;
 791
 792 #ifdef HAVE_LIBSSL
 793         unsigned char digest[EVP_MAX_MD_SIZE];
 794         unsigned int digest_size;
 795         X509 *cert;
 796
 797         cert = SSL_get_peer_certificate(c->ssl_state.ssl);
 798         if (!cert)
 799                 return 0;
 800
 801         if (!X509_digest(cert, EVP_sha256(), digest, &digest_size)) {
 802                 X509_free(cert);
 803                 return 0;
 804         }
 805
 806         X509_free(cert);
 807 #endif /* HAVE_LIBSSL */
 808 #ifdef HAVE_LIBGNUTLS
 809         gnutls_x509_crt_t cert;
 810         unsigned int cert_list_size;
 811         const gnutls_datum_t *cert_list;
 812         unsigned char digest[MAX_HASH_SIZE];
 813         size_t digest_size;
 814
 815         if (gnutls_certificate_type_get(c->ssl_state.gnutls_session) !=
 816                                         GNUTLS_CRT_X509)
 817                 return 0;
 818
 819         if (gnutls_x509_crt_init(&cert) != GNUTLS_E_SUCCESS)
 820                 return 0;
 821
 822         cert_list_size = 0;
 823         cert_list = gnutls_certificate_get_peers(c->ssl_state.gnutls_session,
 824                                                  &cert_list_size);
 825         if (!cert_list) {
 826                 gnutls_x509_crt_deinit(cert);
 827                 return 0;
 828         }
 829
 830         if (gnutls_x509_crt_import(cert, &cert_list[0],
 831                                    GNUTLS_X509_FMT_DER) != GNUTLS_E_SUCCESS) {
 832                 gnutls_x509_crt_deinit(cert);
 833                 return 0;
 834         }
 835
 836         digest_size = sizeof(digest);
 837         if (gnutls_x509_crt_get_fingerprint(cert, GNUTLS_DIG_SHA256, digest,
 838                                             &digest_size)) {
 839                 gnutls_x509_crt_deinit(cert);
 840                 return 0;
 841         }
 842
 843         gnutls_x509_crt_deinit(cert);
 844 #endif /* HAVE_LIBGNUTLS */
 845
 846         assert(c->ssl_state.fingerprint == NULL);
 847
 848         c->ssl_state.fingerprint = malloc(SHA256_STRING_LEN);
 849         if (!c->ssl_state.fingerprint)
 850                 return 0;
 851
 852         for (i = 0; i < (int)digest_size; i++) {
 853                 c->ssl_state.fingerprint[i * 2] = hex[digest[i] / 16];
 854                 c->ssl_state.fingerprint[i * 2 + 1] = hex[digest[i] % 16];
 855         }
 856         c->ssl_state.fingerprint[i * 2] = '\0';
 857
 858         return 1;
 859 }
 860
 861 /* accept/connect wrapper. if connect is true, connect to peer, otherwise wait for incoming connection */
 862 static int
 863 ConnectAccept( CONNECTION *c, bool connect)
 864 {
 865         int ret;
 866 #ifdef HAVE_LIBSSL
 867         SSL *ssl = c->ssl_state.ssl;
 868         assert(ssl != NULL);
 869
 870         ret = connect ? SSL_connect(ssl) : SSL_accept(ssl);
 871         if (1 != ret)
 872                 return ConnSSL_HandleError(c, ret, connect ? "SSL_connect": "SSL_accept");
 873 #endif
 874 #ifdef HAVE_LIBGNUTLS
 875         (void) connect;
 876         ret = gnutls_handshake(c->ssl_state.gnutls_session);
 877         if (ret)
 878                 return ConnSSL_HandleError(c, ret, "gnutls_handshake");
 879 #endif /* _GNUTLS */
 880         (void)ConnSSL_InitCertFp(c);
 881
 882         Conn_OPTION_DEL(c, (CONN_SSL_WANT_WRITE|CONN_SSL_WANT_READ|CONN_SSL_CONNECT));
 883         ConnSSL_LogCertInfo(c);
 884
 885         Conn_StartLogin(CONNECTION2ID(c));
 886         return 1;
 887 }
 888
 889
 890 ssize_t
 891 ConnSSL_Write(CONNECTION *c, const void *buf, size_t count)
 892 {
 893         ssize_t bw;
 894
 895         Conn_OPTION_DEL(c, CONN_SSL_WANT_WRITE|CONN_SSL_WANT_READ);
 896
 897         assert(count > 0);
 898 #ifdef HAVE_LIBSSL
 899         bw = (ssize_t) SSL_write(c->ssl_state.ssl, buf, count);
 900 #endif
 901 #ifdef HAVE_LIBGNUTLS
 902         bw = gnutls_write(c->ssl_state.gnutls_session, buf, count);
 903 #endif
 904         if (bw > 0)
 905                 return bw;
 906         if (ConnSSL_HandleError( c, bw, "ConnSSL_Write") == 0)
 907                 errno = EAGAIN; /* try again */
 908         return -1;
 909 }
 910
 911
 912 ssize_t
 913 ConnSSL_Read(CONNECTION *c, void * buf, size_t count)
 914 {
 915         ssize_t br;
 916
 917         Conn_OPTION_DEL(c, CONN_SSL_WANT_WRITE|CONN_SSL_WANT_READ);
 918 #ifdef HAVE_LIBSSL
 919         br = (ssize_t) SSL_read(c->ssl_state.ssl, buf, count);
 920         if (br > 0)     /* on EOF we have to call ConnSSL_HandleError(), see SSL_read(3) */
 921                 return br;
 922 #endif
 923 #ifdef HAVE_LIBGNUTLS
 924         br = gnutls_read(c->ssl_state.gnutls_session, buf, count);
 925         if (br >= 0)    /* on EOF we must _not_ call ConnSSL_HandleError, see gnutls_record_recv(3) */
 926                 return br;
 927 #endif
 928         /* error on read: switch ConnSSL_HandleError() return values -> 0 is "try again", so return -1 and set EAGAIN */
 929         if (ConnSSL_HandleError(c, br, "ConnSSL_Read") == 0) {
 930                 errno = EAGAIN;
 931                 return -1;
 932         }
 933         return 0;
 934 }
 935
 936
 937 bool
 938 ConnSSL_GetCipherInfo(CONNECTION *c, char *buf, size_t len)
 939 {
 940 #ifdef HAVE_LIBSSL
 941         char *nl;
 942         SSL *ssl = c->ssl_state.ssl;
 943
 944         if (!ssl)
 945                 return false;
 946         *buf = 0;
 947         SSL_CIPHER_description(SSL_get_current_cipher(ssl), buf, len);
 948         nl = strchr(buf, '\n');
 949         if (nl)
 950                 *nl = 0;
 951         return true;
 952 #endif
 953 #ifdef HAVE_LIBGNUTLS
 954         if (Conn_OPTION_ISSET(c, CONN_SSL)) {
 955                 const char *name_cipher, *name_mac, *name_proto, *name_keyexchange;
 956                 unsigned keysize;
 957
 958                 gnutls_session_t sess = c->ssl_state.gnutls_session;
 959                 gnutls_cipher_algorithm_t cipher = gnutls_cipher_get(sess);
 960                 name_cipher = gnutls_cipher_get_name(cipher);
 961                 name_mac = gnutls_mac_get_name(gnutls_mac_get(sess));
 962                 keysize = gnutls_cipher_get_key_size(cipher) * 8;
 963                 name_proto = gnutls_protocol_get_name(gnutls_protocol_get_version(sess));
 964                 name_keyexchange = gnutls_kx_get_name(gnutls_kx_get(sess));
 965
 966                 return snprintf(buf, len, "%s-%s%15s Kx=%s      Enc=%s(%u) Mac=%s",
 967                         name_cipher, name_mac, name_proto, name_keyexchange, name_cipher, keysize, name_mac) > 0;
 968         }
 969         return false;
 970 #endif
 971 }
 972
 973 char *
 974 ConnSSL_GetCertFp(CONNECTION *c)
 975 {
 976         return c->ssl_state.fingerprint;
 977 }
 978
 979 bool
 980 ConnSSL_SetCertFp(CONNECTION *c, const char *fingerprint)
 981 {
 982         assert (c != NULL);
 983         c->ssl_state.fingerprint = strndup(fingerprint, SHA256_STRING_LEN - 1);
 984         return c->ssl_state.fingerprint != NULL;
 985 }
 986 #else
 987
 988 bool
 989 ConnSSL_InitLibrary(void)
 990 {
 991         return true;
 992 }
 993
 994 #endif /* SSL_SUPPORT */
 995 /* -eof- */