src/modules/extra/m_ssl_gnutls.cpp

   1 /*
   2  * InspIRCd -- Internet Relay Chat Daemon
   3  *
   4  *   Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
   5  *   Copyright (C) 2008 John Brooks <john.brooks@dereferenced.net>
   6  *   Copyright (C) 2006-2008 Craig Edwards <craigedwards@brainbox.cc>
   7  *   Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
   8  *   Copyright (C) 2006 Oliver Lupton <oliverlupton@gmail.com>
   9  *
  10  * This file is part of InspIRCd.  InspIRCd is free software: you can
  11  * redistribute it and/or modify it under the terms of the GNU General Public
  12  * License as published by the Free Software Foundation, version 2.
  13  *
  14  * This program is distributed in the hope that it will be useful, but WITHOUT
  15  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  16  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  17  * details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21  */
  22
  23
  24 #include "inspircd.h"
  25 #include <gcrypt.h>
  26 #include <gnutls/gnutls.h>
  27 #include <gnutls/x509.h>
  28 #include "ssl.h"
  29 #include "m_cap.h"
  30
  31 #ifdef _WIN32
  32 # pragma comment(lib, "libgnutls.lib")
  33 # pragma comment(lib, "libgcrypt.lib")
  34 # pragma comment(lib, "libgpg-error.lib")
  35 # pragma comment(lib, "user32.lib")
  36 # pragma comment(lib, "advapi32.lib")
  37 # pragma comment(lib, "libgcc.lib")
  38 # pragma comment(lib, "libmingwex.lib")
  39 # pragma comment(lib, "gdi32.lib")
  40 #endif
  41
  42 /* $ModDesc: Provides SSL support for clients */
  43 /* $CompileFlags: pkgconfincludes("gnutls","/gnutls/gnutls.h","") exec("libgcrypt-config --cflags") */
  44 /* $LinkerFlags: rpath("pkg-config --libs gnutls") pkgconflibs("gnutls","/libgnutls.so","-lgnutls") exec("libgcrypt-config --libs") */
  45 /* $NoPedantic */
  46
  47 // These don't exist in older GnuTLS versions
  48 #if ((GNUTLS_VERSION_MAJOR > 2) || (GNUTLS_VERSION_MAJOR == 2 && GNUTLS_VERSION_MINOR > 1) || (GNUTLS_VERSION_MAJOR == 2 && GNUTLS_VERSION_MINOR == 1 && GNUTLS_VERSION_MICRO >= 7))
  49 #define GNUTLS_NEW_PRIO_API
  50 #endif
  51
  52 #if(GNUTLS_VERSION_MAJOR < 2)
  53 typedef gnutls_certificate_credentials_t gnutls_certificate_credentials;
  54 typedef gnutls_dh_params_t gnutls_dh_params;
  55 #endif
  56
  57 enum issl_status { ISSL_NONE, ISSL_HANDSHAKING_READ, ISSL_HANDSHAKING_WRITE, ISSL_HANDSHAKEN, ISSL_CLOSING, ISSL_CLOSED };
  58
  59 static std::vector<gnutls_x509_crt_t> x509_certs;
  60 static gnutls_x509_privkey_t x509_key;
  61 #if(GNUTLS_VERSION_MAJOR < 2 || ( GNUTLS_VERSION_MAJOR == 2 && GNUTLS_VERSION_MINOR < 12 ) )
  62 static int cert_callback (gnutls_session_t session, const gnutls_datum_t * req_ca_rdn, int nreqs,
  63         const gnutls_pk_algorithm_t * sign_algos, int sign_algos_length, gnutls_retr_st * st) {
  64
  65         st->type = GNUTLS_CRT_X509;
  66 #else
  67 static int cert_callback (gnutls_session_t session, const gnutls_datum_t * req_ca_rdn, int nreqs,
  68         const gnutls_pk_algorithm_t * sign_algos, int sign_algos_length, gnutls_retr2_st * st) {
  69         st->cert_type = GNUTLS_CRT_X509;
  70         st->key_type = GNUTLS_PRIVKEY_X509;
  71 #endif
  72         st->ncerts = x509_certs.size();
  73         st->cert.x509 = &x509_certs[0];
  74         st->key.x509 = x509_key;
  75         st->deinit_all = 0;
  76
  77         return 0;
  78 }
  79
  80 static ssize_t gnutls_pull_wrapper(gnutls_transport_ptr_t user_wrap, void* buffer, size_t size)
  81 {
  82         StreamSocket* user = reinterpret_cast<StreamSocket*>(user_wrap);
  83         if (user->GetEventMask() & FD_READ_WILL_BLOCK)
  84         {
  85                 errno = EAGAIN;
  86                 return -1;
  87         }
  88         int rv = ServerInstance->SE->Recv(user, reinterpret_cast<char *>(buffer), size, 0);
  89         if (rv < 0)
  90         {
  91                 /* On Windows we need to set errno for gnutls */
  92                 if (SocketEngine::IgnoreError())
  93                         errno = EAGAIN;
  94         }
  95         if (rv < (int)size)
  96                 ServerInstance->SE->ChangeEventMask(user, FD_READ_WILL_BLOCK);
  97         return rv;
  98 }
  99
 100 static ssize_t gnutls_push_wrapper(gnutls_transport_ptr_t user_wrap, const void* buffer, size_t size)
 101 {
 102         StreamSocket* user = reinterpret_cast<StreamSocket*>(user_wrap);
 103         if (user->GetEventMask() & FD_WRITE_WILL_BLOCK)
 104         {
 105                 errno = EAGAIN;
 106                 return -1;
 107         }
 108         int rv = ServerInstance->SE->Send(user, reinterpret_cast<const char *>(buffer), size, 0);
 109         if (rv < 0)
 110         {
 111                 /* On Windows we need to set errno for gnutls */
 112                 if (SocketEngine::IgnoreError())
 113                         errno = EAGAIN;
 114         }
 115         if (rv < (int)size)
 116                 ServerInstance->SE->ChangeEventMask(user, FD_WRITE_WILL_BLOCK);
 117         return rv;
 118 }
 119
 120 class RandGen : public HandlerBase2<void, char*, size_t>
 121 {
 122  public:
 123         RandGen() {}
 124         void Call(char* buffer, size_t len)
 125         {
 126                 gcry_randomize(buffer, len, GCRY_STRONG_RANDOM);
 127         }
 128 };
 129
 130 /** Represents an SSL user's extra data
 131  */
 132 class issl_session
 133 {
 134 public:
 135         gnutls_session_t sess;
 136         issl_status status;
 137         reference<ssl_cert> cert;
 138         issl_session() : sess(NULL) {}
 139 };
 140
 141 class CommandStartTLS : public SplitCommand
 142 {
 143  public:
 144         bool enabled;
 145         CommandStartTLS (Module* mod) : SplitCommand(mod, "STARTTLS")
 146         {
 147                 enabled = true;
 148                 works_before_reg = true;
 149         }
 150
 151         CmdResult HandleLocal(const std::vector<std::string> &parameters, LocalUser *user)
 152         {
 153                 if (!enabled)
 154                 {
 155                         user->WriteNumeric(691, "%s :STARTTLS is not enabled", user->nick.c_str());
 156                         return CMD_FAILURE;
 157                 }
 158
 159                 if (user->registered == REG_ALL)
 160                 {
 161                         user->WriteNumeric(691, "%s :STARTTLS is not permitted after client registration is complete", user->nick.c_str());
 162                 }
 163                 else
 164                 {
 165                         if (!user->eh.GetIOHook())
 166                         {
 167                                 user->WriteNumeric(670, "%s :STARTTLS successful, go ahead with TLS handshake", user->nick.c_str());
 168                                 /* We need to flush the write buffer prior to adding the IOHook,
 169                                  * otherwise we'll be sending this line inside the SSL session - which
 170                                  * won't start its handshake until the client gets this line. Currently,
 171                                  * we assume the write will not block here; this is usually safe, as
 172                                  * STARTTLS is sent very early on in the registration phase, where the
 173                                  * user hasn't built up much sendq. Handling a blocked write here would
 174                                  * be very annoying.
 175                                  */
 176                                 user->eh.DoWrite();
 177                                 user->eh.AddIOHook(creator);
 178                                 creator->OnStreamSocketAccept(&user->eh, NULL, NULL);
 179                         }
 180                         else
 181                                 user->WriteNumeric(691, "%s :STARTTLS failure", user->nick.c_str());
 182                 }
 183
 184                 return CMD_FAILURE;
 185         }
 186 };
 187
 188 class ModuleSSLGnuTLS : public Module
 189 {
 190         issl_session* sessions;
 191
 192         gnutls_certificate_credentials_t x509_cred;
 193         gnutls_dh_params_t dh_params;
 194         gnutls_digest_algorithm_t hash;
 195         #ifdef GNUTLS_NEW_PRIO_API
 196         gnutls_priority_t priority;
 197         #endif
 198
 199         std::string sslports;
 200         int dh_bits;
 201
 202         bool cred_alloc;
 203         bool dh_alloc;
 204
 205         RandGen randhandler;
 206         CommandStartTLS starttls;
 207
 208         GenericCap capHandler;
 209         ServiceProvider iohook;
 210
 211         inline static const char* UnknownIfNULL(const char* str)
 212         {
 213                 return str ? str : "UNKNOWN";
 214         }
 215
 216  public:
 217
 218         ModuleSSLGnuTLS()
 219                 : starttls(this), capHandler(this, "tls"), iohook(this, "ssl/gnutls", SERVICE_IOHOOK)
 220         {
 221                 gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
 222
 223                 sessions = new issl_session[ServerInstance->SE->GetMaxFds()];
 224
 225                 gnutls_global_init(); // This must be called once in the program
 226                 gnutls_x509_privkey_init(&x509_key);
 227
 228                 #ifdef GNUTLS_NEW_PRIO_API
 229                 // Init this here so it's always initialized, avoids an extra boolean
 230                 gnutls_priority_init(&priority, "NORMAL", NULL);
 231                 #endif
 232
 233                 cred_alloc = false;
 234                 dh_alloc = false;
 235         }
 236
 237         void init()
 238         {
 239                 // Needs the flag as it ignores a plain /rehash
 240                 OnModuleRehash(NULL,"ssl");
 241
 242                 ServerInstance->GenRandom = &randhandler;
 243
 244                 // Void return, guess we assume success
 245                 gnutls_certificate_set_dh_params(x509_cred, dh_params);
 246                 Implementation eventlist[] = { I_On005Numeric, I_OnRehash, I_OnModuleRehash, I_OnUserConnect,
 247                         I_OnEvent, I_OnHookIO };
 248                 ServerInstance->Modules->Attach(eventlist, this, sizeof(eventlist)/sizeof(Implementation));
 249
 250                 ServerInstance->Modules->AddService(iohook);
 251                 ServerInstance->Modules->AddService(starttls);
 252         }
 253
 254         void OnRehash(User* user)
 255         {
 256                 sslports.clear();
 257
 258                 ConfigTag* Conf = ServerInstance->Config->ConfValue("gnutls");
 259                 starttls.enabled = Conf->getBool("starttls", true);
 260
 261                 if (Conf->getBool("showports", true))
 262                 {
 263                         sslports = Conf->getString("advertisedports");
 264                         if (!sslports.empty())
 265                                 return;
 266
 267                         for (size_t i = 0; i < ServerInstance->ports.size(); i++)
 268                         {
 269                                 ListenSocket* port = ServerInstance->ports[i];
 270                                 if (port->bind_tag->getString("ssl") != "gnutls")
 271                                         continue;
 272
 273                                 const std::string& portid = port->bind_desc;
 274                                 ServerInstance->Logs->Log("m_ssl_gnutls", DEFAULT, "m_ssl_gnutls.so: Enabling SSL for port %s", portid.c_str());
 275
 276                                 if (port->bind_tag->getString("type", "clients") == "clients" && port->bind_addr != "127.0.0.1")
 277                                 {
 278                                         /*
 279                                          * Found an SSL port for clients that is not bound to 127.0.0.1 and handled by us, display
 280                                          * the IP:port in ISUPPORT.
 281                                          *
 282                                          * We used to advertise all ports seperated by a ';' char that matched the above criteria,
 283                                          * but this resulted in too long ISUPPORT lines if there were lots of ports to be displayed.
 284                                          * To solve this by default we now only display the first IP:port found and let the user
 285                                          * configure the exact value for the 005 token, if necessary.
 286                                          */
 287                                         sslports = portid;
 288                                         break;
 289                                 }
 290                         }
 291                 }
 292         }
 293
 294         void OnModuleRehash(User* user, const std::string &param)
 295         {
 296                 if(param != "ssl")
 297                         return;
 298
 299                 std::string keyfile;
 300                 std::string certfile;
 301                 std::string cafile;
 302                 std::string crlfile;
 303                 OnRehash(user);
 304
 305                 ConfigTag* Conf = ServerInstance->Config->ConfValue("gnutls");
 306
 307                 cafile = Conf->getString("cafile", CONFIG_PATH "/ca.pem");
 308                 crlfile = Conf->getString("crlfile", CONFIG_PATH "/crl.pem");
 309                 certfile = Conf->getString("certfile", CONFIG_PATH "/cert.pem");
 310                 keyfile = Conf->getString("keyfile", CONFIG_PATH "/key.pem");
 311                 dh_bits = Conf->getInt("dhbits");
 312                 std::string hashname = Conf->getString("hash", "md5");
 313
 314                 // The GnuTLS manual states that the gnutls_set_default_priority()
 315                 // call we used previously when initializing the session is the same
 316                 // as setting the "NORMAL" priority string.
 317                 // Thus if the setting below is not in the config we will behave exactly
 318                 // the same as before, when the priority setting wasn't available.
 319                 std::string priorities = Conf->getString("priority", "NORMAL");
 320
 321                 if((dh_bits != 768) && (dh_bits != 1024) && (dh_bits != 2048) && (dh_bits != 3072) && (dh_bits != 4096))
 322                         dh_bits = 1024;
 323
 324                 if (hashname == "md5")
 325                         hash = GNUTLS_DIG_MD5;
 326                 else if (hashname == "sha1")
 327                         hash = GNUTLS_DIG_SHA1;
 328                 else
 329                         throw ModuleException("Unknown hash type " + hashname);
 330
 331
 332                 int ret;
 333
 334                 if (dh_alloc)
 335                 {
 336                         gnutls_dh_params_deinit(dh_params);
 337                         dh_alloc = false;
 338                         dh_params = NULL;
 339                 }
 340
 341                 if (cred_alloc)
 342                 {
 343                         // Deallocate the old credentials
 344                         gnutls_certificate_free_credentials(x509_cred);
 345
 346                         for(unsigned int i=0; i < x509_certs.size(); i++)
 347                                 gnutls_x509_crt_deinit(x509_certs[i]);
 348                         x509_certs.clear();
 349                 }
 350
 351                 ret = gnutls_certificate_allocate_credentials(&x509_cred);
 352                 cred_alloc = (ret >= 0);
 353                 if (!cred_alloc)
 354                         ServerInstance->Logs->Log("m_ssl_gnutls",DEBUG, "m_ssl_gnutls.so: Failed to allocate certificate credentials: %s", gnutls_strerror(ret));
 355
 356                 if((ret =gnutls_certificate_set_x509_trust_file(x509_cred, cafile.c_str(), GNUTLS_X509_FMT_PEM)) < 0)
 357                         ServerInstance->Logs->Log("m_ssl_gnutls",DEBUG, "m_ssl_gnutls.so: Failed to set X.509 trust file '%s': %s", cafile.c_str(), gnutls_strerror(ret));
 358
 359                 if((ret = gnutls_certificate_set_x509_crl_file (x509_cred, crlfile.c_str(), GNUTLS_X509_FMT_PEM)) < 0)
 360                         ServerInstance->Logs->Log("m_ssl_gnutls",DEBUG, "m_ssl_gnutls.so: Failed to set X.509 CRL file '%s': %s", crlfile.c_str(), gnutls_strerror(ret));
 361
 362                 FileReader reader;
 363
 364                 reader.LoadFile(certfile);
 365                 std::string cert_string = reader.Contents();
 366                 gnutls_datum_t cert_datum = { (unsigned char*)cert_string.data(), static_cast<unsigned int>(cert_string.length()) };
 367
 368                 reader.LoadFile(keyfile);
 369                 std::string key_string = reader.Contents();
 370                 gnutls_datum_t key_datum = { (unsigned char*)key_string.data(), static_cast<unsigned int>(key_string.length()) };
 371
 372                 // If this fails, no SSL port will work. At all. So, do the smart thing - throw a ModuleException
 373                 unsigned int certcount = 3;
 374                 x509_certs.resize(certcount);
 375                 ret = gnutls_x509_crt_list_import(&x509_certs[0], &certcount, &cert_datum, GNUTLS_X509_FMT_PEM, GNUTLS_X509_CRT_LIST_IMPORT_FAIL_IF_EXCEED);
 376                 if (ret == GNUTLS_E_SHORT_MEMORY_BUFFER)
 377                 {
 378                         // the buffer wasn't big enough to hold all certs but gnutls updated certcount to the number of available certs, try again with a bigger buffer
 379                         x509_certs.resize(certcount);
 380                         ret = gnutls_x509_crt_list_import(&x509_certs[0], &certcount, &cert_datum, GNUTLS_X509_FMT_PEM, GNUTLS_X509_CRT_LIST_IMPORT_FAIL_IF_EXCEED);
 381                 }
 382
 383                 if (ret <= 0)
 384                 {
 385                         // clear the vector so we won't call gnutls_x509_crt_deinit() on the (uninited) certs later
 386                         x509_certs.clear();
 387                         throw ModuleException("Unable to load GnuTLS server certificate (" + certfile + "): " + ((ret < 0) ? (std::string(gnutls_strerror(ret))) : "No certs could be read"));
 388                 }
 389                 x509_certs.resize(ret);
 390
 391                 if((ret = gnutls_x509_privkey_import(x509_key, &key_datum, GNUTLS_X509_FMT_PEM)) < 0)
 392                         throw ModuleException("Unable to load GnuTLS server private key (" + keyfile + "): " + std::string(gnutls_strerror(ret)));
 393
 394                 if((ret = gnutls_certificate_set_x509_key(x509_cred, &x509_certs[0], certcount, x509_key)) < 0)
 395                         throw ModuleException("Unable to set GnuTLS cert/key pair: " + std::string(gnutls_strerror(ret)));
 396
 397                 #ifdef GNUTLS_NEW_PRIO_API
 398                 // It's safe to call this every time as we cannot have this uninitialized, see constructor and below.
 399                 gnutls_priority_deinit(priority);
 400
 401                 // Try to set the priorities for ciphers, kex methods etc. to the user supplied string
 402                 // If the user did not supply anything then the string is already set to "NORMAL"
 403                 const char* priocstr = priorities.c_str();
 404                 const char* prioerror;
 405
 406                 if ((ret = gnutls_priority_init(&priority, priocstr, &prioerror)) < 0)
 407                 {
 408                         // gnutls did not understand the user supplied string, log and fall back to the default priorities
 409                         ServerInstance->Logs->Log("m_ssl_gnutls",DEFAULT, "m_ssl_gnutls.so: Failed to set priorities to \"%s\": %s Syntax error at position %u, falling back to default (NORMAL)", priorities.c_str(), gnutls_strerror(ret), (unsigned int) (prioerror - priocstr));
 410                         gnutls_priority_init(&priority, "NORMAL", NULL);
 411                 }
 412
 413                 #else
 414                 if (priorities != "NORMAL")
 415                         ServerInstance->Logs->Log("m_ssl_gnutls",DEFAULT, "m_ssl_gnutls.so: You've set <gnutls:priority> to a value other than the default, but this is only supported with GnuTLS v2.1.7 or newer. Your GnuTLS version is older than that so the option will have no effect.");
 416                 #endif
 417
 418                 #if(GNUTLS_VERSION_MAJOR < 2 || ( GNUTLS_VERSION_MAJOR == 2 && GNUTLS_VERSION_MINOR < 12 ) )
 419                 gnutls_certificate_client_set_retrieve_function (x509_cred, cert_callback);
 420                 #else
 421                 gnutls_certificate_set_retrieve_function (x509_cred, cert_callback);
 422                 #endif
 423                 ret = gnutls_dh_params_init(&dh_params);
 424                 dh_alloc = (ret >= 0);
 425                 if (!dh_alloc)
 426                 {
 427                         ServerInstance->Logs->Log("m_ssl_gnutls",DEFAULT, "m_ssl_gnutls.so: Failed to initialise DH parameters: %s", gnutls_strerror(ret));
 428                         return;
 429                 }
 430
 431                 std::string dhfile = Conf->getString("dhfile");
 432                 if (!dhfile.empty())
 433                 {
 434                         // Try to load DH params from file
 435                         reader.LoadFile(dhfile);
 436                         std::string dhstring = reader.Contents();
 437                         gnutls_datum_t dh_datum = { (unsigned char*)dhstring.data(), static_cast<unsigned int>(dhstring.length()) };
 438
 439                         if ((ret = gnutls_dh_params_import_pkcs3(dh_params, &dh_datum, GNUTLS_X509_FMT_PEM)) < 0)
 440                         {
 441                                 // File unreadable or GnuTLS was unhappy with the contents, generate the DH primes now
 442                                 ServerInstance->Logs->Log("m_ssl_gnutls", DEFAULT, "m_ssl_gnutls.so: Generating DH parameters because I failed to load them from file '%s': %s", dhfile.c_str(), gnutls_strerror(ret));
 443                                 GenerateDHParams();
 444                         }
 445                 }
 446                 else
 447                 {
 448                         GenerateDHParams();
 449                 }
 450         }
 451
 452         void GenerateDHParams()
 453         {
 454                 // Generate Diffie Hellman parameters - for use with DHE
 455                 // kx algorithms. These should be discarded and regenerated
 456                 // once a day, once a week or once a month. Depending on the
 457                 // security requirements.
 458
 459                 if (!dh_alloc)
 460                         return;
 461
 462                 int ret;
 463
 464                 if((ret = gnutls_dh_params_generate2(dh_params, dh_bits)) < 0)
 465                         ServerInstance->Logs->Log("m_ssl_gnutls",DEFAULT, "m_ssl_gnutls.so: Failed to generate DH parameters (%d bits): %s", dh_bits, gnutls_strerror(ret));
 466         }
 467
 468         ~ModuleSSLGnuTLS()
 469         {
 470                 for(unsigned int i=0; i < x509_certs.size(); i++)
 471                         gnutls_x509_crt_deinit(x509_certs[i]);
 472
 473                 gnutls_x509_privkey_deinit(x509_key);
 474                 #ifdef GNUTLS_NEW_PRIO_API
 475                 gnutls_priority_deinit(priority);
 476                 #endif
 477
 478                 if (dh_alloc)
 479                         gnutls_dh_params_deinit(dh_params);
 480                 if (cred_alloc)
 481                         gnutls_certificate_free_credentials(x509_cred);
 482
 483                 gnutls_global_deinit();
 484                 delete[] sessions;
 485                 ServerInstance->GenRandom = &ServerInstance->HandleGenRandom;
 486         }
 487
 488         void OnCleanup(int target_type, void* item)
 489         {
 490                 if(target_type == TYPE_USER)
 491                 {
 492                         LocalUser* user = IS_LOCAL(static_cast<User*>(item));
 493
 494                         if (user && user->eh.GetIOHook() == this)
 495                         {
 496                                 // User is using SSL, they're a local user, and they're using one of *our* SSL ports.
 497                                 // Potentially there could be multiple SSL modules loaded at once on different ports.
 498                                 ServerInstance->Users->QuitUser(user, "SSL module unloading");
 499                         }
 500                 }
 501         }
 502
 503         Version GetVersion()
 504         {
 505                 return Version("Provides SSL support for clients", VF_VENDOR);
 506         }
 507
 508
 509         void On005Numeric(std::string &output)
 510         {
 511                 if (!sslports.empty())
 512                         output.append(" SSL=" + sslports);
 513                 if (starttls.enabled)
 514                         output.append(" STARTTLS");
 515         }
 516
 517         void OnHookIO(StreamSocket* user, ListenSocket* lsb)
 518         {
 519                 if (!user->GetIOHook() && lsb->bind_tag->getString("ssl") == "gnutls")
 520                 {
 521                         /* Hook the user with our module */
 522                         user->AddIOHook(this);
 523                 }
 524         }
 525
 526         void OnRequest(Request& request)
 527         {
 528                 if (strcmp("GET_SSL_CERT", request.id) == 0)
 529                 {
 530                         SocketCertificateRequest& req = static_cast<SocketCertificateRequest&>(request);
 531                         int fd = req.sock->GetFd();
 532                         issl_session* session = &sessions[fd];
 533
 534                         req.cert = session->cert;
 535                 }
 536         }
 537
 538         void InitSession(StreamSocket* user, bool me_server)
 539         {
 540                 issl_session* session = &sessions[user->GetFd()];
 541
 542                 gnutls_init(&session->sess, me_server ? GNUTLS_SERVER : GNUTLS_CLIENT);
 543
 544                 #ifdef GNUTLS_NEW_PRIO_API
 545                 gnutls_priority_set(session->sess, priority);
 546                 #endif
 547                 gnutls_credentials_set(session->sess, GNUTLS_CRD_CERTIFICATE, x509_cred);
 548                 gnutls_dh_set_prime_bits(session->sess, dh_bits);
 549                 gnutls_transport_set_ptr(session->sess, reinterpret_cast<gnutls_transport_ptr_t>(user));
 550                 gnutls_transport_set_push_function(session->sess, gnutls_push_wrapper);
 551                 gnutls_transport_set_pull_function(session->sess, gnutls_pull_wrapper);
 552
 553                 if (me_server)
 554                         gnutls_certificate_server_set_request(session->sess, GNUTLS_CERT_REQUEST); // Request client certificate if any.
 555
 556                 Handshake(session, user);
 557         }
 558
 559         void OnStreamSocketAccept(StreamSocket* user, irc::sockets::sockaddrs* client, irc::sockets::sockaddrs* server)
 560         {
 561                 issl_session* session = &sessions[user->GetFd()];
 562
 563                 /* For STARTTLS: Don't try and init a session on a socket that already has a session */
 564                 if (session->sess)
 565                         return;
 566
 567                 InitSession(user, true);
 568         }
 569
 570         void OnStreamSocketConnect(StreamSocket* user)
 571         {
 572                 InitSession(user, false);
 573         }
 574
 575         void OnStreamSocketClose(StreamSocket* user)
 576         {
 577                 CloseSession(&sessions[user->GetFd()]);
 578         }
 579
 580         int OnStreamSocketRead(StreamSocket* user, std::string& recvq)
 581         {
 582                 issl_session* session = &sessions[user->GetFd()];
 583
 584                 if (!session->sess)
 585                 {
 586                         CloseSession(session);
 587                         user->SetError("No SSL session");
 588                         return -1;
 589                 }
 590
 591                 if (session->status == ISSL_HANDSHAKING_READ || session->status == ISSL_HANDSHAKING_WRITE)
 592                 {
 593                         // The handshake isn't finished, try to finish it.
 594
 595                         if(!Handshake(session, user))
 596                         {
 597                                 if (session->status != ISSL_CLOSING)
 598                                         return 0;
 599                                 return -1;
 600                         }
 601                 }
 602
 603                 // If we resumed the handshake then session->status will be ISSL_HANDSHAKEN.
 604
 605                 if (session->status == ISSL_HANDSHAKEN)
 606                 {
 607                         char* buffer = ServerInstance->GetReadBuffer();
 608                         size_t bufsiz = ServerInstance->Config->NetBufferSize;
 609                         int ret = gnutls_record_recv(session->sess, buffer, bufsiz);
 610                         if (ret > 0)
 611                         {
 612                                 recvq.append(buffer, ret);
 613                                 return 1;
 614                         }
 615                         else if (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED)
 616                         {
 617                                 return 0;
 618                         }
 619                         else if (ret == 0)
 620                         {
 621                                 user->SetError("Connection closed");
 622                                 CloseSession(session);
 623                                 return -1;
 624                         }
 625                         else
 626                         {
 627                                 user->SetError(gnutls_strerror(ret));
 628                                 CloseSession(session);
 629                                 return -1;
 630                         }
 631                 }
 632                 else if (session->status == ISSL_CLOSING)
 633                         return -1;
 634
 635                 return 0;
 636         }
 637
 638         int OnStreamSocketWrite(StreamSocket* user, std::string& sendq)
 639         {
 640                 issl_session* session = &sessions[user->GetFd()];
 641
 642                 if (!session->sess)
 643                 {
 644                         CloseSession(session);
 645                         user->SetError("No SSL session");
 646                         return -1;
 647                 }
 648
 649                 if (session->status == ISSL_HANDSHAKING_WRITE || session->status == ISSL_HANDSHAKING_READ)
 650                 {
 651                         // The handshake isn't finished, try to finish it.
 652                         Handshake(session, user);
 653                         if (session->status != ISSL_CLOSING)
 654                                 return 0;
 655                         return -1;
 656                 }
 657
 658                 int ret = 0;
 659
 660                 if (session->status == ISSL_HANDSHAKEN)
 661                 {
 662                         ret = gnutls_record_send(session->sess, sendq.data(), sendq.length());
 663
 664                         if (ret == (int)sendq.length())
 665                         {
 666                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_NO_WRITE);
 667                                 return 1;
 668                         }
 669                         else if (ret > 0)
 670                         {
 671                                 sendq = sendq.substr(ret);
 672                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_SINGLE_WRITE);
 673                                 return 0;
 674                         }
 675                         else if (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED || ret == 0)
 676                         {
 677                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_SINGLE_WRITE);
 678                                 return 0;
 679                         }
 680                         else // (ret < 0)
 681                         {
 682                                 user->SetError(gnutls_strerror(ret));
 683                                 CloseSession(session);
 684                                 return -1;
 685                         }
 686                 }
 687
 688                 return 0;
 689         }
 690
 691         bool Handshake(issl_session* session, StreamSocket* user)
 692         {
 693                 int ret = gnutls_handshake(session->sess);
 694
 695                 if (ret < 0)
 696                 {
 697                         if(ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED)
 698                         {
 699                                 // Handshake needs resuming later, read() or write() would have blocked.
 700
 701                                 if(gnutls_record_get_direction(session->sess) == 0)
 702                                 {
 703                                         // gnutls_handshake() wants to read() again.
 704                                         session->status = ISSL_HANDSHAKING_READ;
 705                                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_POLL_READ | FD_WANT_NO_WRITE);
 706                                 }
 707                                 else
 708                                 {
 709                                         // gnutls_handshake() wants to write() again.
 710                                         session->status = ISSL_HANDSHAKING_WRITE;
 711                                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_NO_READ | FD_WANT_SINGLE_WRITE);
 712                                 }
 713                         }
 714                         else
 715                         {
 716                                 user->SetError("Handshake Failed - " + std::string(gnutls_strerror(ret)));
 717                                 CloseSession(session);
 718                                 session->status = ISSL_CLOSING;
 719                         }
 720
 721                         return false;
 722                 }
 723                 else
 724                 {
 725                         // Change the seesion state
 726                         session->status = ISSL_HANDSHAKEN;
 727
 728                         VerifyCertificate(session,user);
 729
 730                         // Finish writing, if any left
 731                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_POLL_READ | FD_WANT_NO_WRITE | FD_ADD_TRIAL_WRITE);
 732
 733                         return true;
 734                 }
 735         }
 736
 737         void OnUserConnect(LocalUser* user)
 738         {
 739                 if (user->eh.GetIOHook() == this)
 740                 {
 741                         if (sessions[user->eh.GetFd()].sess)
 742                         {
 743                                 const gnutls_session_t& sess = sessions[user->eh.GetFd()].sess;
 744                                 std::string cipher = UnknownIfNULL(gnutls_kx_get_name(gnutls_kx_get(sess)));
 745                                 cipher.append("-").append(UnknownIfNULL(gnutls_cipher_get_name(gnutls_cipher_get(sess)))).append("-");
 746                                 cipher.append(UnknownIfNULL(gnutls_mac_get_name(gnutls_mac_get(sess))));
 747
 748                                 ssl_cert* cert = sessions[user->eh.GetFd()].cert;
 749                                 if (cert->fingerprint.empty())
 750                                         user->WriteServ("NOTICE %s :*** You are connected using SSL cipher \"%s\"", user->nick.c_str(), cipher.c_str());
 751                                 else
 752                                         user->WriteServ("NOTICE %s :*** You are connected using SSL cipher \"%s\""
 753                                                 " and your SSL fingerprint is %s", user->nick.c_str(), cipher.c_str(), cert->fingerprint.c_str());
 754                         }
 755                 }
 756         }
 757
 758         void CloseSession(issl_session* session)
 759         {
 760                 if (session->sess)
 761                 {
 762                         gnutls_bye(session->sess, GNUTLS_SHUT_WR);
 763                         gnutls_deinit(session->sess);
 764                 }
 765                 session->sess = NULL;
 766                 session->cert = NULL;
 767                 session->status = ISSL_NONE;
 768         }
 769
 770         void VerifyCertificate(issl_session* session, StreamSocket* user)
 771         {
 772                 if (!session->sess || !user)
 773                         return;
 774
 775                 unsigned int status;
 776                 const gnutls_datum_t* cert_list;
 777                 int ret;
 778                 unsigned int cert_list_size;
 779                 gnutls_x509_crt_t cert;
 780                 char name[MAXBUF];
 781                 unsigned char digest[MAXBUF];
 782                 size_t digest_size = sizeof(digest);
 783                 size_t name_size = sizeof(name);
 784                 ssl_cert* certinfo = new ssl_cert;
 785                 session->cert = certinfo;
 786
 787                 /* This verification function uses the trusted CAs in the credentials
 788                  * structure. So you must have installed one or more CA certificates.
 789                  */
 790                 ret = gnutls_certificate_verify_peers2(session->sess, &status);
 791
 792                 if (ret < 0)
 793                 {
 794                         certinfo->error = std::string(gnutls_strerror(ret));
 795                         return;
 796                 }
 797
 798                 certinfo->invalid = (status & GNUTLS_CERT_INVALID);
 799                 certinfo->unknownsigner = (status & GNUTLS_CERT_SIGNER_NOT_FOUND);
 800                 certinfo->revoked = (status & GNUTLS_CERT_REVOKED);
 801                 certinfo->trusted = !(status & GNUTLS_CERT_SIGNER_NOT_CA);
 802
 803                 /* Up to here the process is the same for X.509 certificates and
 804                  * OpenPGP keys. From now on X.509 certificates are assumed. This can
 805                  * be easily extended to work with openpgp keys as well.
 806                  */
 807                 if (gnutls_certificate_type_get(session->sess) != GNUTLS_CRT_X509)
 808                 {
 809                         certinfo->error = "No X509 keys sent";
 810                         return;
 811                 }
 812
 813                 ret = gnutls_x509_crt_init(&cert);
 814                 if (ret < 0)
 815                 {
 816                         certinfo->error = gnutls_strerror(ret);
 817                         return;
 818                 }
 819
 820                 cert_list_size = 0;
 821                 cert_list = gnutls_certificate_get_peers(session->sess, &cert_list_size);
 822                 if (cert_list == NULL)
 823                 {
 824                         certinfo->error = "No certificate was found";
 825                         goto info_done_dealloc;
 826                 }
 827
 828                 /* This is not a real world example, since we only check the first
 829                  * certificate in the given chain.
 830                  */
 831
 832                 ret = gnutls_x509_crt_import(cert, &cert_list[0], GNUTLS_X509_FMT_DER);
 833                 if (ret < 0)
 834                 {
 835                         certinfo->error = gnutls_strerror(ret);
 836                         goto info_done_dealloc;
 837                 }
 838
 839                 gnutls_x509_crt_get_dn(cert, name, &name_size);
 840                 certinfo->dn = name;
 841
 842                 gnutls_x509_crt_get_issuer_dn(cert, name, &name_size);
 843                 certinfo->issuer = name;
 844
 845                 if ((ret = gnutls_x509_crt_get_fingerprint(cert, hash, digest, &digest_size)) < 0)
 846                 {
 847                         certinfo->error = gnutls_strerror(ret);
 848                 }
 849                 else
 850                 {
 851                         certinfo->fingerprint = irc::hex(digest, digest_size);
 852                 }
 853
 854                 /* Beware here we do not check for errors.
 855                  */
 856                 if ((gnutls_x509_crt_get_expiration_time(cert) < ServerInstance->Time()) || (gnutls_x509_crt_get_activation_time(cert) > ServerInstance->Time()))
 857                 {
 858                         certinfo->error = "Not activated, or expired certificate";
 859                 }
 860
 861 info_done_dealloc:
 862                 gnutls_x509_crt_deinit(cert);
 863         }
 864
 865         void OnEvent(Event& ev)
 866         {
 867                 if (starttls.enabled)
 868                         capHandler.HandleEvent(ev);
 869         }
 870 };
 871
 872 MODULE_INIT(ModuleSSLGnuTLS)