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