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 OPENSSL_API_COMPAT < 0x10100000L
 287         if (!ssl_ctx) {
 288                 SSL_library_init();
 289                 SSL_load_error_strings();
 290         }
 291 #endif
 292
 293         if (!RAND_status()) {
 294                 Log(LOG_ERR, "OpenSSL PRNG not seeded: /dev/urandom missing?");
 295                 /*
 296                  * it is probably best to fail and let the user install EGD or
 297                  * a similar program if no kernel random device is available.
 298                  * According to OpenSSL RAND_egd(3): "The automatic query of
 299                  * /var/run/egd-pool et al was added in OpenSSL 0.9.7";
 300                  * so it makes little sense to deal with PRNGD seeding ourselves.
 301                  */
 302                 array_free(&Conf_SSLOptions.ListenPorts);
 303                 return false;
 304         }
 305
 306         newctx = SSL_CTX_new(SSLv23_method());
 307         if (!newctx) {
 308                 LogOpenSSLError("Failed to create SSL context", NULL);
 309                 array_free(&Conf_SSLOptions.ListenPorts);
 310                 return false;
 311         }
 312
 313         if (!ConnSSL_LoadServerKey_openssl(newctx))
 314                 goto out;
 315
 316         if (SSL_CTX_set_cipher_list(newctx, Conf_SSLOptions.CipherList) == 0) {
 317                 Log(LOG_ERR, "Failed to apply OpenSSL cipher list \"%s\"!",
 318                     Conf_SSLOptions.CipherList);
 319                 goto out;
 320         }
 321
 322         SSL_CTX_set_session_id_context(newctx, (unsigned char *)"ngircd", 6);
 323         SSL_CTX_set_options(newctx, SSL_OP_SINGLE_DH_USE|SSL_OP_NO_SSLv2);
 324         SSL_CTX_set_mode(newctx, SSL_MODE_ENABLE_PARTIAL_WRITE);
 325         SSL_CTX_set_verify(newctx, SSL_VERIFY_PEER|SSL_VERIFY_CLIENT_ONCE,
 326                            Verify_openssl);
 327         SSL_CTX_free(ssl_ctx);
 328         ssl_ctx = newctx;
 329         Log(LOG_INFO, "%s initialized.", SSLeay_version(SSLEAY_VERSION));
 330         return true;
 331 out:
 332         SSL_CTX_free(newctx);
 333         array_free(&Conf_SSLOptions.ListenPorts);
 334         return false;
 335 #endif
 336 #ifdef HAVE_LIBGNUTLS
 337         int err;
 338         static bool initialized;
 339
 340         if (initialized) {
 341                 /* TODO: cannot reload gnutls keys: can't simply free x509
 342                  * context -- it may still be in use */
 343                 return false;
 344         }
 345
 346         err = gnutls_global_init();
 347         if (err) {
 348                 Log(LOG_ERR, "Failed to initialize GnuTLS: %s",
 349                     gnutls_strerror(err));
 350                 goto out;
 351         }
 352
 353         if (!ConnSSL_LoadServerKey_gnutls())
 354                 goto out;
 355
 356         if (gnutls_priority_init(&priorities_cache, Conf_SSLOptions.CipherList,
 357                                  NULL) != GNUTLS_E_SUCCESS) {
 358                 Log(LOG_ERR,
 359                     "Failed to apply GnuTLS cipher list \"%s\"!",
 360                     Conf_SSLOptions.CipherList);
 361                 goto out;
 362         }
 363
 364         Log(LOG_INFO, "GnuTLS %s initialized.", gnutls_check_version(NULL));
 365         initialized = true;
 366         return true;
 367 out:
 368         array_free(&Conf_SSLOptions.ListenPorts);
 369         return false;
 370 #endif
 371 }
 372
 373
 374 #ifdef HAVE_LIBGNUTLS
 375 static bool
 376 ConnSSL_LoadServerKey_gnutls(void)
 377 {
 378         int err;
 379         const char *cert_file;
 380
 381         err = gnutls_certificate_allocate_credentials(&x509_cred);
 382         if (err < 0) {
 383                 Log(LOG_ERR, "Failed to allocate certificate credentials: %s",
 384                     gnutls_strerror(err));
 385                 return false;
 386         }
 387
 388         cert_file = Conf_SSLOptions.CertFile ? Conf_SSLOptions.CertFile:Conf_SSLOptions.KeyFile;
 389         if (!cert_file) {
 390                 Log(LOG_ERR, "No SSL server key configured!");
 391                 return false;
 392         }
 393
 394         if (array_bytes(&Conf_SSLOptions.KeyFilePassword))
 395                 Log(LOG_WARNING,
 396                     "Ignoring SSL \"KeyFilePassword\": Not supported by GnuTLS.");
 397
 398         if (!Load_DH_params())
 399                 return false;
 400
 401         gnutls_certificate_set_dh_params(x509_cred, dh_params);
 402         err = gnutls_certificate_set_x509_key_file(x509_cred, cert_file, Conf_SSLOptions.KeyFile, GNUTLS_X509_FMT_PEM);
 403         if (err < 0) {
 404                 Log(LOG_ERR,
 405                     "Failed to set certificate key file (cert %s, key %s): %s",
 406                     cert_file,
 407                     Conf_SSLOptions.KeyFile ? Conf_SSLOptions.KeyFile : "(NULL)",
 408                     gnutls_strerror(err));
 409                 return false;
 410         }
 411         return true;
 412 }
 413 #endif
 414
 415
 416 #ifdef HAVE_LIBSSL
 417 static bool
 418 ConnSSL_LoadServerKey_openssl(SSL_CTX *ctx)
 419 {
 420         char *cert_key;
 421
 422         assert(ctx);
 423         if (!Conf_SSLOptions.KeyFile) {
 424                 Log(LOG_ERR, "No SSL server key configured!");
 425                 return false;
 426         }
 427
 428         SSL_CTX_set_default_passwd_cb(ctx, pem_passwd_cb);
 429         SSL_CTX_set_default_passwd_cb_userdata(ctx, &Conf_SSLOptions.KeyFilePassword);
 430
 431         if (SSL_CTX_use_PrivateKey_file(ctx, Conf_SSLOptions.KeyFile, SSL_FILETYPE_PEM) != 1) {
 432                 array_free_wipe(&Conf_SSLOptions.KeyFilePassword);
 433                 LogOpenSSLError("Failed to add private key", Conf_SSLOptions.KeyFile);
 434                 return false;
 435         }
 436
 437         cert_key = Conf_SSLOptions.CertFile ? Conf_SSLOptions.CertFile:Conf_SSLOptions.KeyFile;
 438         if (SSL_CTX_use_certificate_chain_file(ctx, cert_key) != 1) {
 439                 array_free_wipe(&Conf_SSLOptions.KeyFilePassword);
 440                 LogOpenSSLError("Failed to load certificate chain", cert_key);
 441                 return false;
 442         }
 443
 444         array_free_wipe(&Conf_SSLOptions.KeyFilePassword);
 445
 446         if (!SSL_CTX_check_private_key(ctx)) {
 447                 LogOpenSSLError("Server private key does not match certificate", NULL);
 448                 return false;
 449         }
 450         if (Load_DH_params()) {
 451                 if (SSL_CTX_set_tmp_dh(ctx, dh_params) != 1)
 452                         LogOpenSSLError("Error setting DH parameters", Conf_SSLOptions.DHFile);
 453                 /* don't return false here: the non-DH modes will still work */
 454                 DH_free(dh_params);
 455                 dh_params = NULL;
 456         }
 457         return true;
 458 }
 459
 460
 461 #endif
 462 static bool
 463 ConnSSL_Init_SSL(CONNECTION *c)
 464 {
 465         int ret;
 466
 467         LogDebug("Initializing SSL ...");
 468         assert(c != NULL);
 469
 470 #ifdef HAVE_LIBSSL
 471         if (!ssl_ctx) {
 472                 Log(LOG_ERR,
 473                     "Can't initialize SSL context, OpenSSL initialization failed at startup!");
 474                 return false;
 475         }
 476         assert(c->ssl_state.ssl == NULL);
 477         assert(c->ssl_state.fingerprint == NULL);
 478
 479         c->ssl_state.ssl = SSL_new(ssl_ctx);
 480         if (!c->ssl_state.ssl) {
 481                 LogOpenSSLError("Failed to create SSL structure", NULL);
 482                 return false;
 483         }
 484         Conn_OPTION_ADD(c, CONN_SSL);
 485
 486         ret = SSL_set_fd(c->ssl_state.ssl, c->sock);
 487         if (ret != 1) {
 488                 LogOpenSSLError("Failed to set SSL file descriptor", NULL);
 489                 ConnSSL_Free(c);
 490                 return false;
 491         }
 492 #endif
 493 #ifdef HAVE_LIBGNUTLS
 494         Conn_OPTION_ADD(c, CONN_SSL);
 495         ret = gnutls_priority_set(c->ssl_state.gnutls_session, priorities_cache);
 496         if (ret != GNUTLS_E_SUCCESS) {
 497                 Log(LOG_ERR, "Failed to set GnuTLS session priorities: %s",
 498                     gnutls_strerror(ret));
 499                 ConnSSL_Free(c);
 500                 return false;
 501         }
 502         /*
 503          * The intermediate (long) cast is here to avoid a warning like:
 504          * "cast to pointer from integer of different size" on 64-bit platforms.
 505          * There doesn't seem to be an alternate GNUTLS API we could use instead, see e.g.
 506          * http://www.mail-archive.com/help-gnutls@gnu.org/msg00286.html
 507          */
 508         gnutls_transport_set_ptr(c->ssl_state.gnutls_session,
 509                                  (gnutls_transport_ptr_t) (long) c->sock);
 510         gnutls_certificate_server_set_request(c->ssl_state.gnutls_session,
 511                                               GNUTLS_CERT_REQUEST);
 512         ret = gnutls_credentials_set(c->ssl_state.gnutls_session,
 513                                      GNUTLS_CRD_CERTIFICATE, x509_cred);
 514         if (ret != 0) {
 515                 Log(LOG_ERR, "Failed to set SSL credentials: %s",
 516                     gnutls_strerror(ret));
 517                 ConnSSL_Free(c);
 518                 return false;
 519         }
 520         gnutls_dh_set_prime_bits(c->ssl_state.gnutls_session, DH_BITS_MIN);
 521 #endif
 522         return true;
 523 }
 524
 525
 526 bool
 527 ConnSSL_PrepareConnect(CONNECTION *c, UNUSED CONF_SERVER *s)
 528 {
 529         bool ret;
 530 #ifdef HAVE_LIBGNUTLS
 531         int err;
 532
 533         err = gnutls_init(&c->ssl_state.gnutls_session, GNUTLS_CLIENT);
 534         if (err) {
 535                 Log(LOG_ERR, "Failed to initialize new SSL session: %s",
 536                     gnutls_strerror(err));
 537                 return false;
 538         }
 539 #endif
 540         ret = ConnSSL_Init_SSL(c);
 541         if (!ret)
 542                 return false;
 543         Conn_OPTION_ADD(c, CONN_SSL_CONNECT);
 544 #ifdef HAVE_LIBSSL
 545         assert(c->ssl_state.ssl);
 546         SSL_set_verify(c->ssl_state.ssl, SSL_VERIFY_NONE, NULL);
 547 #endif
 548         return true;
 549 }
 550
 551
 552 /**
 553  * Check and handle error return codes after failed calls to SSL functions.
 554  *
 555  * OpenSSL:
 556  * SSL_connect(), SSL_accept(), SSL_do_handshake(), SSL_read(), SSL_peek(), or
 557  * SSL_write() on ssl.
 558  *
 559  * GnuTLS:
 560  * gnutlsssl_read(), gnutls_write() or gnutls_handshake().
 561  *
 562  * @param c The connection handle.
 563  * @prarm code The return code.
 564  * @param fname The name of the function in which the error occurred.
 565  * @return -1 on fatal errors, 0 if we can try again later.
 566  */
 567 static int
 568 ConnSSL_HandleError(CONNECTION * c, const int code, const char *fname)
 569 {
 570 #ifdef HAVE_LIBSSL
 571         int ret = SSL_ERROR_SYSCALL;
 572         unsigned long sslerr;
 573         int real_errno = errno;
 574
 575         ret = SSL_get_error(c->ssl_state.ssl, code);
 576
 577         switch (ret) {
 578         case SSL_ERROR_WANT_READ:
 579                 io_event_del(c->sock, IO_WANTWRITE);
 580                 Conn_OPTION_ADD(c, CONN_SSL_WANT_READ);
 581                 return 0;       /* try again later */
 582         case SSL_ERROR_WANT_WRITE:
 583                 io_event_del(c->sock, IO_WANTREAD);
 584                 Conn_OPTION_ADD(c, CONN_SSL_WANT_WRITE); /* fall through */
 585         case SSL_ERROR_NONE:
 586                 return 0;       /* try again later */
 587         case SSL_ERROR_ZERO_RETURN:
 588                 LogDebug("SSL connection shut down normally.");
 589                 break;
 590         case SSL_ERROR_SYSCALL:
 591                 /* SSL_ERROR_WANT_CONNECT, SSL_ERROR_WANT_ACCEPT,
 592                  * and SSL_ERROR_WANT_X509_LOOKUP */
 593                 sslerr = ERR_get_error();
 594                 if (sslerr) {
 595                         Log(LOG_ERR, "SSL error: %s [in %s()]!",
 596                             ERR_error_string(sslerr, NULL), fname);
 597                 } else {
 598                         switch (code) { /* EOF that violated protocol */
 599                         case 0:
 600                                 Log(LOG_ERR,
 601                                     "SSL error, client disconnected [in %s()]!",
 602                                     fname);
 603                                 break;
 604                         case -1:        /* low level socket I/O error, check errno */
 605                                 Log(LOG_ERR, "SSL error: %s [in %s()]!",
 606                                     strerror(real_errno), fname);
 607                         }
 608                 }
 609                 break;
 610         case SSL_ERROR_SSL:
 611                 LogOpenSSLError("SSL protocol error", fname);
 612                 break;
 613         default:
 614                 Log(LOG_ERR, "Unknown SSL error %d [in %s()]!", ret, fname);
 615         }
 616         ConnSSL_Free(c);
 617         return -1;
 618 #endif
 619 #ifdef HAVE_LIBGNUTLS
 620         switch (code) {
 621         case GNUTLS_E_AGAIN:
 622         case GNUTLS_E_INTERRUPTED:
 623                 if (gnutls_record_get_direction(c->ssl_state.gnutls_session)) {
 624                         Conn_OPTION_ADD(c, CONN_SSL_WANT_WRITE);
 625                         io_event_del(c->sock, IO_WANTREAD);
 626                 } else {
 627                         Conn_OPTION_ADD(c, CONN_SSL_WANT_READ);
 628                         io_event_del(c->sock, IO_WANTWRITE);
 629                 }
 630                 break;
 631         default:
 632                 assert(code < 0);
 633                 if (gnutls_error_is_fatal(code)) {
 634                         Log(LOG_ERR, "SSL error: %s [%s].",
 635                             gnutls_strerror(code), fname);
 636                         ConnSSL_Free(c);
 637                         return -1;
 638                 }
 639         }
 640         return 0;
 641 #endif
 642 }
 643
 644
 645 static void
 646 ConnSSL_LogCertInfo( CONNECTION *c )
 647 {
 648 #ifdef HAVE_LIBSSL
 649         SSL *ssl = c->ssl_state.ssl;
 650
 651         assert(ssl);
 652
 653         Log(LOG_INFO, "Connection %d: initialized %s using cipher %s.",
 654                 c->sock, SSL_get_version(ssl), SSL_get_cipher(ssl));
 655 #endif
 656 #ifdef HAVE_LIBGNUTLS
 657         gnutls_session_t sess = c->ssl_state.gnutls_session;
 658         gnutls_cipher_algorithm_t cipher = gnutls_cipher_get(sess);
 659
 660         Log(LOG_INFO, "Connection %d: initialized %s using cipher %s-%s.",
 661             c->sock,
 662             gnutls_protocol_get_name(gnutls_protocol_get_version(sess)),
 663             gnutls_cipher_get_name(cipher),
 664             gnutls_mac_get_name(gnutls_mac_get(sess)));
 665 #endif
 666 }
 667
 668
 669 /*
 670  Accept incoming SSL connection.
 671  Return Values:
 672          1: SSL Connection established
 673          0: try again
 674         -1: SSL Connection not established due to fatal error.
 675 */
 676 int
 677 ConnSSL_Accept( CONNECTION *c )
 678 {
 679         assert(c != NULL);
 680         if (!Conn_OPTION_ISSET(c, CONN_SSL)) {
 681 #ifdef HAVE_LIBGNUTLS
 682                 int err = gnutls_init(&c->ssl_state.gnutls_session, GNUTLS_SERVER);
 683                 if (err) {
 684                         Log(LOG_ERR, "Failed to initialize new SSL session: %s",
 685                             gnutls_strerror(err));
 686                         return false;
 687                 }
 688 #endif
 689                 if (!ConnSSL_Init_SSL(c))
 690                         return -1;
 691         }
 692         return ConnectAccept(c, false );
 693 }
 694
 695
 696 int
 697 ConnSSL_Connect( CONNECTION *c )
 698 {
 699         assert(c != NULL);
 700 #ifdef HAVE_LIBSSL
 701         assert(c->ssl_state.ssl);
 702 #endif
 703         assert(Conn_OPTION_ISSET(c, CONN_SSL));
 704         return ConnectAccept(c, true);
 705 }
 706
 707 static int
 708 ConnSSL_InitCertFp( CONNECTION *c )
 709 {
 710         const char hex[] = "0123456789abcdef";
 711         int i;
 712
 713 #ifdef HAVE_LIBSSL
 714         unsigned char digest[EVP_MAX_MD_SIZE];
 715         unsigned int digest_size;
 716         X509 *cert;
 717
 718         cert = SSL_get_peer_certificate(c->ssl_state.ssl);
 719         if (!cert)
 720                 return 0;
 721
 722         if (!X509_digest(cert, EVP_sha256(), digest, &digest_size)) {
 723                 X509_free(cert);
 724                 return 0;
 725         }
 726
 727         X509_free(cert);
 728 #endif /* HAVE_LIBSSL */
 729 #ifdef HAVE_LIBGNUTLS
 730         gnutls_x509_crt_t cert;
 731         unsigned int cert_list_size;
 732         const gnutls_datum_t *cert_list;
 733         unsigned char digest[MAX_HASH_SIZE];
 734         size_t digest_size;
 735
 736         if (gnutls_certificate_type_get(c->ssl_state.gnutls_session) !=
 737                                         GNUTLS_CRT_X509)
 738                 return 0;
 739
 740         if (gnutls_x509_crt_init(&cert) != GNUTLS_E_SUCCESS)
 741                 return 0;
 742
 743         cert_list_size = 0;
 744         cert_list = gnutls_certificate_get_peers(c->ssl_state.gnutls_session,
 745                                                  &cert_list_size);
 746         if (!cert_list) {
 747                 gnutls_x509_crt_deinit(cert);
 748                 return 0;
 749         }
 750
 751         if (gnutls_x509_crt_import(cert, &cert_list[0],
 752                                    GNUTLS_X509_FMT_DER) != GNUTLS_E_SUCCESS) {
 753                 gnutls_x509_crt_deinit(cert);
 754                 return 0;
 755         }
 756
 757         digest_size = sizeof(digest);
 758         if (gnutls_x509_crt_get_fingerprint(cert, GNUTLS_DIG_SHA256, digest,
 759                                             &digest_size)) {
 760                 gnutls_x509_crt_deinit(cert);
 761                 return 0;
 762         }
 763
 764         gnutls_x509_crt_deinit(cert);
 765 #endif /* HAVE_LIBGNUTLS */
 766
 767         assert(c->ssl_state.fingerprint == NULL);
 768
 769         c->ssl_state.fingerprint = malloc(SHA256_STRING_LEN);
 770         if (!c->ssl_state.fingerprint)
 771                 return 0;
 772
 773         for (i = 0; i < (int)digest_size; i++) {
 774                 c->ssl_state.fingerprint[i * 2] = hex[digest[i] / 16];
 775                 c->ssl_state.fingerprint[i * 2 + 1] = hex[digest[i] % 16];
 776         }
 777         c->ssl_state.fingerprint[i * 2] = '\0';
 778
 779         return 1;
 780 }
 781
 782 /* accept/connect wrapper. if connect is true, connect to peer, otherwise wait for incoming connection */
 783 static int
 784 ConnectAccept( CONNECTION *c, bool connect)
 785 {
 786         int ret;
 787 #ifdef HAVE_LIBSSL
 788         SSL *ssl = c->ssl_state.ssl;
 789         assert(ssl != NULL);
 790
 791         ret = connect ? SSL_connect(ssl) : SSL_accept(ssl);
 792         if (1 != ret)
 793                 return ConnSSL_HandleError(c, ret, connect ? "SSL_connect": "SSL_accept");
 794 #endif
 795 #ifdef HAVE_LIBGNUTLS
 796         (void) connect;
 797         ret = gnutls_handshake(c->ssl_state.gnutls_session);
 798         if (ret)
 799                 return ConnSSL_HandleError(c, ret, "gnutls_handshake");
 800 #endif /* _GNUTLS */
 801         (void)ConnSSL_InitCertFp(c);
 802
 803         Conn_OPTION_DEL(c, (CONN_SSL_WANT_WRITE|CONN_SSL_WANT_READ|CONN_SSL_CONNECT));
 804         ConnSSL_LogCertInfo(c);
 805
 806         Conn_StartLogin(CONNECTION2ID(c));
 807         return 1;
 808 }
 809
 810
 811 ssize_t
 812 ConnSSL_Write(CONNECTION *c, const void *buf, size_t count)
 813 {
 814         ssize_t bw;
 815
 816         Conn_OPTION_DEL(c, CONN_SSL_WANT_WRITE|CONN_SSL_WANT_READ);
 817
 818         assert(count > 0);
 819 #ifdef HAVE_LIBSSL
 820         bw = (ssize_t) SSL_write(c->ssl_state.ssl, buf, count);
 821 #endif
 822 #ifdef HAVE_LIBGNUTLS
 823         bw = gnutls_write(c->ssl_state.gnutls_session, buf, count);
 824 #endif
 825         if (bw > 0)
 826                 return bw;
 827         if (ConnSSL_HandleError( c, bw, "ConnSSL_Write") == 0)
 828                 errno = EAGAIN; /* try again */
 829         return -1;
 830 }
 831
 832
 833 ssize_t
 834 ConnSSL_Read(CONNECTION *c, void * buf, size_t count)
 835 {
 836         ssize_t br;
 837
 838         Conn_OPTION_DEL(c, CONN_SSL_WANT_WRITE|CONN_SSL_WANT_READ);
 839 #ifdef HAVE_LIBSSL
 840         br = (ssize_t) SSL_read(c->ssl_state.ssl, buf, count);
 841         if (br > 0)     /* on EOF we have to call ConnSSL_HandleError(), see SSL_read(3) */
 842                 return br;
 843 #endif
 844 #ifdef HAVE_LIBGNUTLS
 845         br = gnutls_read(c->ssl_state.gnutls_session, buf, count);
 846         if (br >= 0)    /* on EOF we must _not_ call ConnSSL_HandleError, see gnutls_record_recv(3) */
 847                 return br;
 848 #endif
 849         /* error on read: switch ConnSSL_HandleError() return values -> 0 is "try again", so return -1 and set EAGAIN */
 850         if (ConnSSL_HandleError(c, br, "ConnSSL_Read") == 0) {
 851                 errno = EAGAIN;
 852                 return -1;
 853         }
 854         return 0;
 855 }
 856
 857
 858 bool
 859 ConnSSL_GetCipherInfo(CONNECTION *c, char *buf, size_t len)
 860 {
 861 #ifdef HAVE_LIBSSL
 862         char *nl;
 863         SSL *ssl = c->ssl_state.ssl;
 864
 865         if (!ssl)
 866                 return false;
 867         *buf = 0;
 868         SSL_CIPHER_description(SSL_get_current_cipher(ssl), buf, len);
 869         nl = strchr(buf, '\n');
 870         if (nl)
 871                 *nl = 0;
 872         return true;
 873 #endif
 874 #ifdef HAVE_LIBGNUTLS
 875         if (Conn_OPTION_ISSET(c, CONN_SSL)) {
 876                 const char *name_cipher, *name_mac, *name_proto, *name_keyexchange;
 877                 unsigned keysize;
 878
 879                 gnutls_session_t sess = c->ssl_state.gnutls_session;
 880                 gnutls_cipher_algorithm_t cipher = gnutls_cipher_get(sess);
 881                 name_cipher = gnutls_cipher_get_name(cipher);
 882                 name_mac = gnutls_mac_get_name(gnutls_mac_get(sess));
 883                 keysize = gnutls_cipher_get_key_size(cipher) * 8;
 884                 name_proto = gnutls_protocol_get_name(gnutls_protocol_get_version(sess));
 885                 name_keyexchange = gnutls_kx_get_name(gnutls_kx_get(sess));
 886
 887                 return snprintf(buf, len, "%s-%s%15s Kx=%s      Enc=%s(%u) Mac=%s",
 888                         name_cipher, name_mac, name_proto, name_keyexchange, name_cipher, keysize, name_mac) > 0;
 889         }
 890         return false;
 891 #endif
 892 }
 893
 894 char *
 895 ConnSSL_GetCertFp(CONNECTION *c)
 896 {
 897         return c->ssl_state.fingerprint;
 898 }
 899
 900 bool
 901 ConnSSL_SetCertFp(CONNECTION *c, const char *fingerprint)
 902 {
 903         assert (c != NULL);
 904         c->ssl_state.fingerprint = strndup(fingerprint, SHA256_STRING_LEN - 1);
 905         return c->ssl_state.fingerprint != NULL;
 906 }
 907 #else
 908
 909 bool
 910 ConnSSL_InitLibrary(void)
 911 {
 912         return true;
 913 }
 914
 915 #endif /* SSL_SUPPORT */
 916 /* -eof- */