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