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 "modules/ssl.h"
  29 #include "modules/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 class RandGen : public HandlerBase2<void, char*, size_t>
  81 {
  82  public:
  83         RandGen() {}
  84         void Call(char* buffer, size_t len)
  85         {
  86                 gcry_randomize(buffer, len, GCRY_STRONG_RANDOM);
  87         }
  88 };
  89
  90 /** Represents an SSL user's extra data
  91  */
  92 class issl_session
  93 {
  94 public:
  95         StreamSocket* socket;
  96         gnutls_session_t sess;
  97         issl_status status;
  98         reference<ssl_cert> cert;
  99
 100         issl_session() : socket(NULL), sess(NULL) {}
 101 };
 102
 103 class CommandStartTLS : public SplitCommand
 104 {
 105  public:
 106         bool enabled;
 107         CommandStartTLS (Module* mod) : SplitCommand(mod, "STARTTLS")
 108         {
 109                 enabled = true;
 110                 works_before_reg = true;
 111         }
 112
 113         CmdResult HandleLocal(const std::vector<std::string> &parameters, LocalUser *user)
 114         {
 115                 if (!enabled)
 116                 {
 117                         user->WriteNumeric(691, "%s :STARTTLS is not enabled", user->nick.c_str());
 118                         return CMD_FAILURE;
 119                 }
 120
 121                 if (user->registered == REG_ALL)
 122                 {
 123                         user->WriteNumeric(691, "%s :STARTTLS is not permitted after client registration is complete", user->nick.c_str());
 124                 }
 125                 else
 126                 {
 127                         if (!user->eh.GetIOHook())
 128                         {
 129                                 user->WriteNumeric(670, "%s :STARTTLS successful, go ahead with TLS handshake", user->nick.c_str());
 130                                 /* We need to flush the write buffer prior to adding the IOHook,
 131                                  * otherwise we'll be sending this line inside the SSL session - which
 132                                  * won't start its handshake until the client gets this line. Currently,
 133                                  * we assume the write will not block here; this is usually safe, as
 134                                  * STARTTLS is sent very early on in the registration phase, where the
 135                                  * user hasn't built up much sendq. Handling a blocked write here would
 136                                  * be very annoying.
 137                                  */
 138                                 user->eh.DoWrite();
 139                                 user->eh.AddIOHook(creator);
 140                                 creator->OnStreamSocketAccept(&user->eh, NULL, NULL);
 141                         }
 142                         else
 143                                 user->WriteNumeric(691, "%s :STARTTLS failure", user->nick.c_str());
 144                 }
 145
 146                 return CMD_FAILURE;
 147         }
 148 };
 149
 150 class ModuleSSLGnuTLS : public Module
 151 {
 152         issl_session* sessions;
 153
 154         gnutls_certificate_credentials_t x509_cred;
 155         gnutls_dh_params_t dh_params;
 156         gnutls_digest_algorithm_t hash;
 157         #ifdef GNUTLS_NEW_PRIO_API
 158         gnutls_priority_t priority;
 159         #endif
 160
 161         std::string sslports;
 162         int dh_bits;
 163
 164         bool cred_alloc;
 165         bool dh_alloc;
 166
 167         RandGen randhandler;
 168         CommandStartTLS starttls;
 169
 170         GenericCap capHandler;
 171         ServiceProvider iohook;
 172
 173         inline static const char* UnknownIfNULL(const char* str)
 174         {
 175                 return str ? str : "UNKNOWN";
 176         }
 177
 178         static ssize_t gnutls_pull_wrapper(gnutls_transport_ptr_t session_wrap, void* buffer, size_t size)
 179         {
 180                 issl_session* session = reinterpret_cast<issl_session*>(session_wrap);
 181                 if (session->socket->GetEventMask() & FD_READ_WILL_BLOCK)
 182                 {
 183 #ifdef _WIN32
 184                         gnutls_transport_set_errno(session->sess, EAGAIN);
 185 #else
 186                         errno = EAGAIN;
 187 #endif
 188                         return -1;
 189                 }
 190
 191                 int rv = ServerInstance->SE->Recv(session->socket, reinterpret_cast<char *>(buffer), size, 0);
 192
 193 #ifdef _WIN32
 194                 if (rv < 0)
 195                 {
 196                         /* Windows doesn't use errno, but gnutls does, so check SocketEngine::IgnoreError()
 197                          * and then set errno appropriately.
 198                          * The gnutls library may also have a different errno variable than us, see
 199                          * gnutls_transport_set_errno(3).
 200                          */
 201                         gnutls_transport_set_errno(session->sess, SocketEngine::IgnoreError() ? EAGAIN : errno);
 202                 }
 203 #endif
 204
 205                 if (rv < (int)size)
 206                         ServerInstance->SE->ChangeEventMask(session->socket, FD_READ_WILL_BLOCK);
 207                 return rv;
 208         }
 209
 210         static ssize_t gnutls_push_wrapper(gnutls_transport_ptr_t session_wrap, const void* buffer, size_t size)
 211         {
 212                 issl_session* session = reinterpret_cast<issl_session*>(session_wrap);
 213                 if (session->socket->GetEventMask() & FD_WRITE_WILL_BLOCK)
 214                 {
 215 #ifdef _WIN32
 216                         gnutls_transport_set_errno(session->sess, EAGAIN);
 217 #else
 218                         errno = EAGAIN;
 219 #endif
 220                         return -1;
 221                 }
 222
 223                 int rv = ServerInstance->SE->Send(session->socket, reinterpret_cast<const char *>(buffer), size, 0);
 224
 225 #ifdef _WIN32
 226                 if (rv < 0)
 227                 {
 228                         /* Windows doesn't use errno, but gnutls does, so check SocketEngine::IgnoreError()
 229                          * and then set errno appropriately.
 230                          * The gnutls library may also have a different errno variable than us, see
 231                          * gnutls_transport_set_errno(3).
 232                          */
 233                         gnutls_transport_set_errno(session->sess, SocketEngine::IgnoreError() ? EAGAIN : errno);
 234                 }
 235 #endif
 236
 237                 if (rv < (int)size)
 238                         ServerInstance->SE->ChangeEventMask(session->socket, FD_WRITE_WILL_BLOCK);
 239                 return rv;
 240         }
 241
 242  public:
 243         ModuleSSLGnuTLS()
 244                 : starttls(this), capHandler(this, "tls"), iohook(this, "ssl/gnutls", SERVICE_IOHOOK)
 245         {
 246                 gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
 247
 248                 sessions = new issl_session[ServerInstance->SE->GetMaxFds()];
 249
 250                 gnutls_global_init(); // This must be called once in the program
 251                 gnutls_x509_privkey_init(&x509_key);
 252
 253                 #ifdef GNUTLS_NEW_PRIO_API
 254                 // Init this here so it's always initialized, avoids an extra boolean
 255                 gnutls_priority_init(&priority, "NORMAL", NULL);
 256                 #endif
 257
 258                 cred_alloc = false;
 259                 dh_alloc = false;
 260         }
 261
 262         void init() CXX11_OVERRIDE
 263         {
 264                 // Needs the flag as it ignores a plain /rehash
 265                 OnModuleRehash(NULL,"ssl");
 266
 267                 ServerInstance->GenRandom = &randhandler;
 268
 269                 // Void return, guess we assume success
 270                 gnutls_certificate_set_dh_params(x509_cred, dh_params);
 271                 Implementation eventlist[] = { I_On005Numeric, I_OnRehash, I_OnModuleRehash, I_OnUserConnect,
 272                         I_OnEvent, I_OnHookIO };
 273                 ServerInstance->Modules->Attach(eventlist, this, sizeof(eventlist)/sizeof(Implementation));
 274
 275                 ServerInstance->Modules->AddService(iohook);
 276                 ServerInstance->Modules->AddService(starttls);
 277         }
 278
 279         void OnRehash(User* user) CXX11_OVERRIDE
 280         {
 281                 sslports.clear();
 282
 283                 ConfigTag* Conf = ServerInstance->Config->ConfValue("gnutls");
 284                 starttls.enabled = Conf->getBool("starttls", true);
 285
 286                 if (Conf->getBool("showports", true))
 287                 {
 288                         sslports = Conf->getString("advertisedports");
 289                         if (!sslports.empty())
 290                                 return;
 291
 292                         for (size_t i = 0; i < ServerInstance->ports.size(); i++)
 293                         {
 294                                 ListenSocket* port = ServerInstance->ports[i];
 295                                 if (port->bind_tag->getString("ssl") != "gnutls")
 296                                         continue;
 297
 298                                 const std::string& portid = port->bind_desc;
 299                                 ServerInstance->Logs->Log("m_ssl_gnutls", LOG_DEFAULT, "m_ssl_gnutls.so: Enabling SSL for port %s", portid.c_str());
 300
 301                                 if (port->bind_tag->getString("type", "clients") == "clients" && port->bind_addr != "127.0.0.1")
 302                                 {
 303                                         /*
 304                                          * Found an SSL port for clients that is not bound to 127.0.0.1 and handled by us, display
 305                                          * the IP:port in ISUPPORT.
 306                                          *
 307                                          * We used to advertise all ports seperated by a ';' char that matched the above criteria,
 308                                          * but this resulted in too long ISUPPORT lines if there were lots of ports to be displayed.
 309                                          * To solve this by default we now only display the first IP:port found and let the user
 310                                          * configure the exact value for the 005 token, if necessary.
 311                                          */
 312                                         sslports = portid;
 313                                         break;
 314                                 }
 315                         }
 316                 }
 317         }
 318
 319         void OnModuleRehash(User* user, const std::string &param) CXX11_OVERRIDE
 320         {
 321                 if(param != "ssl")
 322                         return;
 323
 324                 std::string keyfile;
 325                 std::string certfile;
 326                 std::string cafile;
 327                 std::string crlfile;
 328                 OnRehash(user);
 329
 330                 ConfigTag* Conf = ServerInstance->Config->ConfValue("gnutls");
 331
 332                 cafile = Conf->getString("cafile", CONFIG_PATH "/ca.pem");
 333                 crlfile = Conf->getString("crlfile", CONFIG_PATH "/crl.pem");
 334                 certfile = Conf->getString("certfile", CONFIG_PATH "/cert.pem");
 335                 keyfile = Conf->getString("keyfile", CONFIG_PATH "/key.pem");
 336                 dh_bits = Conf->getInt("dhbits");
 337                 std::string hashname = Conf->getString("hash", "md5");
 338
 339                 // The GnuTLS manual states that the gnutls_set_default_priority()
 340                 // call we used previously when initializing the session is the same
 341                 // as setting the "NORMAL" priority string.
 342                 // Thus if the setting below is not in the config we will behave exactly
 343                 // the same as before, when the priority setting wasn't available.
 344                 std::string priorities = Conf->getString("priority", "NORMAL");
 345
 346                 if((dh_bits != 768) && (dh_bits != 1024) && (dh_bits != 2048) && (dh_bits != 3072) && (dh_bits != 4096))
 347                         dh_bits = 1024;
 348
 349                 if (hashname == "md5")
 350                         hash = GNUTLS_DIG_MD5;
 351                 else if (hashname == "sha1")
 352                         hash = GNUTLS_DIG_SHA1;
 353                 else
 354                         throw ModuleException("Unknown hash type " + hashname);
 355
 356
 357                 int ret;
 358
 359                 if (dh_alloc)
 360                 {
 361                         gnutls_dh_params_deinit(dh_params);
 362                         dh_alloc = false;
 363                         dh_params = NULL;
 364                 }
 365
 366                 if (cred_alloc)
 367                 {
 368                         // Deallocate the old credentials
 369                         gnutls_certificate_free_credentials(x509_cred);
 370
 371                         for(unsigned int i=0; i < x509_certs.size(); i++)
 372                                 gnutls_x509_crt_deinit(x509_certs[i]);
 373                         x509_certs.clear();
 374                 }
 375
 376                 ret = gnutls_certificate_allocate_credentials(&x509_cred);
 377                 cred_alloc = (ret >= 0);
 378                 if (!cred_alloc)
 379                         ServerInstance->Logs->Log("m_ssl_gnutls", LOG_DEBUG, "m_ssl_gnutls.so: Failed to allocate certificate credentials: %s", gnutls_strerror(ret));
 380
 381                 if((ret =gnutls_certificate_set_x509_trust_file(x509_cred, cafile.c_str(), GNUTLS_X509_FMT_PEM)) < 0)
 382                         ServerInstance->Logs->Log("m_ssl_gnutls", LOG_DEBUG, "m_ssl_gnutls.so: Failed to set X.509 trust file '%s': %s", cafile.c_str(), gnutls_strerror(ret));
 383
 384                 if((ret = gnutls_certificate_set_x509_crl_file (x509_cred, crlfile.c_str(), GNUTLS_X509_FMT_PEM)) < 0)
 385                         ServerInstance->Logs->Log("m_ssl_gnutls", LOG_DEBUG, "m_ssl_gnutls.so: Failed to set X.509 CRL file '%s': %s", crlfile.c_str(), gnutls_strerror(ret));
 386
 387                 FileReader reader;
 388
 389                 reader.Load(certfile);
 390                 std::string cert_string = reader.GetString();
 391                 gnutls_datum_t cert_datum = { (unsigned char*)cert_string.data(), static_cast<unsigned int>(cert_string.length()) };
 392
 393                 reader.Load(keyfile);
 394                 std::string key_string = reader.GetString();
 395                 gnutls_datum_t key_datum = { (unsigned char*)key_string.data(), static_cast<unsigned int>(key_string.length()) };
 396
 397                 // If this fails, no SSL port will work. At all. So, do the smart thing - throw a ModuleException
 398                 unsigned int certcount = 3;
 399                 x509_certs.resize(certcount);
 400                 ret = gnutls_x509_crt_list_import(&x509_certs[0], &certcount, &cert_datum, GNUTLS_X509_FMT_PEM, GNUTLS_X509_CRT_LIST_IMPORT_FAIL_IF_EXCEED);
 401                 if (ret == GNUTLS_E_SHORT_MEMORY_BUFFER)
 402                 {
 403                         // 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
 404                         x509_certs.resize(certcount);
 405                         ret = gnutls_x509_crt_list_import(&x509_certs[0], &certcount, &cert_datum, GNUTLS_X509_FMT_PEM, GNUTLS_X509_CRT_LIST_IMPORT_FAIL_IF_EXCEED);
 406                 }
 407
 408                 if (ret <= 0)
 409                 {
 410                         // clear the vector so we won't call gnutls_x509_crt_deinit() on the (uninited) certs later
 411                         x509_certs.clear();
 412                         throw ModuleException("Unable to load GnuTLS server certificate (" + certfile + "): " + ((ret < 0) ? (std::string(gnutls_strerror(ret))) : "No certs could be read"));
 413                 }
 414                 x509_certs.resize(ret);
 415
 416                 if((ret = gnutls_x509_privkey_import(x509_key, &key_datum, GNUTLS_X509_FMT_PEM)) < 0)
 417                         throw ModuleException("Unable to load GnuTLS server private key (" + keyfile + "): " + std::string(gnutls_strerror(ret)));
 418
 419                 if((ret = gnutls_certificate_set_x509_key(x509_cred, &x509_certs[0], certcount, x509_key)) < 0)
 420                         throw ModuleException("Unable to set GnuTLS cert/key pair: " + std::string(gnutls_strerror(ret)));
 421
 422                 #ifdef GNUTLS_NEW_PRIO_API
 423                 // It's safe to call this every time as we cannot have this uninitialized, see constructor and below.
 424                 gnutls_priority_deinit(priority);
 425
 426                 // Try to set the priorities for ciphers, kex methods etc. to the user supplied string
 427                 // If the user did not supply anything then the string is already set to "NORMAL"
 428                 const char* priocstr = priorities.c_str();
 429                 const char* prioerror;
 430
 431                 if ((ret = gnutls_priority_init(&priority, priocstr, &prioerror)) < 0)
 432                 {
 433                         // gnutls did not understand the user supplied string, log and fall back to the default priorities
 434                         ServerInstance->Logs->Log("m_ssl_gnutls", LOG_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));
 435                         gnutls_priority_init(&priority, "NORMAL", NULL);
 436                 }
 437
 438                 #else
 439                 if (priorities != "NORMAL")
 440                         ServerInstance->Logs->Log("m_ssl_gnutls", LOG_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.");
 441                 #endif
 442
 443                 #if(GNUTLS_VERSION_MAJOR < 2 || ( GNUTLS_VERSION_MAJOR == 2 && GNUTLS_VERSION_MINOR < 12 ) )
 444                 gnutls_certificate_client_set_retrieve_function (x509_cred, cert_callback);
 445                 #else
 446                 gnutls_certificate_set_retrieve_function (x509_cred, cert_callback);
 447                 #endif
 448                 ret = gnutls_dh_params_init(&dh_params);
 449                 dh_alloc = (ret >= 0);
 450                 if (!dh_alloc)
 451                 {
 452                         ServerInstance->Logs->Log("m_ssl_gnutls", LOG_DEFAULT, "m_ssl_gnutls.so: Failed to initialise DH parameters: %s", gnutls_strerror(ret));
 453                         return;
 454                 }
 455
 456                 std::string dhfile = Conf->getString("dhfile");
 457                 if (!dhfile.empty())
 458                 {
 459                         // Try to load DH params from file
 460                         reader.Load(dhfile);
 461                         std::string dhstring = reader.GetString();
 462                         gnutls_datum_t dh_datum = { (unsigned char*)dhstring.data(), static_cast<unsigned int>(dhstring.length()) };
 463
 464                         if ((ret = gnutls_dh_params_import_pkcs3(dh_params, &dh_datum, GNUTLS_X509_FMT_PEM)) < 0)
 465                         {
 466                                 // File unreadable or GnuTLS was unhappy with the contents, generate the DH primes now
 467                                 ServerInstance->Logs->Log("m_ssl_gnutls", LOG_DEFAULT, "m_ssl_gnutls.so: Generating DH parameters because I failed to load them from file '%s': %s", dhfile.c_str(), gnutls_strerror(ret));
 468                                 GenerateDHParams();
 469                         }
 470                 }
 471                 else
 472                 {
 473                         GenerateDHParams();
 474                 }
 475         }
 476
 477         void GenerateDHParams()
 478         {
 479                 // Generate Diffie Hellman parameters - for use with DHE
 480                 // kx algorithms. These should be discarded and regenerated
 481                 // once a day, once a week or once a month. Depending on the
 482                 // security requirements.
 483
 484                 if (!dh_alloc)
 485                         return;
 486
 487                 int ret;
 488
 489                 if((ret = gnutls_dh_params_generate2(dh_params, dh_bits)) < 0)
 490                         ServerInstance->Logs->Log("m_ssl_gnutls", LOG_DEFAULT, "m_ssl_gnutls.so: Failed to generate DH parameters (%d bits): %s", dh_bits, gnutls_strerror(ret));
 491         }
 492
 493         ~ModuleSSLGnuTLS()
 494         {
 495                 for(unsigned int i=0; i < x509_certs.size(); i++)
 496                         gnutls_x509_crt_deinit(x509_certs[i]);
 497
 498                 gnutls_x509_privkey_deinit(x509_key);
 499                 #ifdef GNUTLS_NEW_PRIO_API
 500                 gnutls_priority_deinit(priority);
 501                 #endif
 502
 503                 if (dh_alloc)
 504                         gnutls_dh_params_deinit(dh_params);
 505                 if (cred_alloc)
 506                         gnutls_certificate_free_credentials(x509_cred);
 507
 508                 gnutls_global_deinit();
 509                 delete[] sessions;
 510                 ServerInstance->GenRandom = &ServerInstance->HandleGenRandom;
 511         }
 512
 513         void OnCleanup(int target_type, void* item) CXX11_OVERRIDE
 514         {
 515                 if(target_type == TYPE_USER)
 516                 {
 517                         LocalUser* user = IS_LOCAL(static_cast<User*>(item));
 518
 519                         if (user && user->eh.GetIOHook() == this)
 520                         {
 521                                 // User is using SSL, they're a local user, and they're using one of *our* SSL ports.
 522                                 // Potentially there could be multiple SSL modules loaded at once on different ports.
 523                                 ServerInstance->Users->QuitUser(user, "SSL module unloading");
 524                         }
 525                 }
 526         }
 527
 528         Version GetVersion() CXX11_OVERRIDE
 529         {
 530                 return Version("Provides SSL support for clients", VF_VENDOR);
 531         }
 532
 533         void On005Numeric(std::map<std::string, std::string>& tokens) CXX11_OVERRIDE
 534         {
 535                 if (!sslports.empty())
 536                         tokens["SSL"] = sslports;
 537                 if (starttls.enabled)
 538                         tokens["STARTTLS"];
 539         }
 540
 541         void OnHookIO(StreamSocket* user, ListenSocket* lsb) CXX11_OVERRIDE
 542         {
 543                 if (!user->GetIOHook() && lsb->bind_tag->getString("ssl") == "gnutls")
 544                 {
 545                         /* Hook the user with our module */
 546                         user->AddIOHook(this);
 547                 }
 548         }
 549
 550         void OnRequest(Request& request) CXX11_OVERRIDE
 551         {
 552                 if (strcmp("GET_SSL_CERT", request.id) == 0)
 553                 {
 554                         SocketCertificateRequest& req = static_cast<SocketCertificateRequest&>(request);
 555                         int fd = req.sock->GetFd();
 556                         issl_session* session = &sessions[fd];
 557
 558                         req.cert = session->cert;
 559                 }
 560         }
 561
 562         void InitSession(StreamSocket* user, bool me_server)
 563         {
 564                 issl_session* session = &sessions[user->GetFd()];
 565
 566                 gnutls_init(&session->sess, me_server ? GNUTLS_SERVER : GNUTLS_CLIENT);
 567                 session->socket = user;
 568
 569                 #ifdef GNUTLS_NEW_PRIO_API
 570                 gnutls_priority_set(session->sess, priority);
 571                 #endif
 572                 gnutls_credentials_set(session->sess, GNUTLS_CRD_CERTIFICATE, x509_cred);
 573                 gnutls_dh_set_prime_bits(session->sess, dh_bits);
 574                 gnutls_transport_set_ptr(session->sess, reinterpret_cast<gnutls_transport_ptr_t>(session));
 575                 gnutls_transport_set_push_function(session->sess, gnutls_push_wrapper);
 576                 gnutls_transport_set_pull_function(session->sess, gnutls_pull_wrapper);
 577
 578                 if (me_server)
 579                         gnutls_certificate_server_set_request(session->sess, GNUTLS_CERT_REQUEST); // Request client certificate if any.
 580
 581                 Handshake(session, user);
 582         }
 583
 584         void OnStreamSocketAccept(StreamSocket* user, irc::sockets::sockaddrs* client, irc::sockets::sockaddrs* server) CXX11_OVERRIDE
 585         {
 586                 issl_session* session = &sessions[user->GetFd()];
 587
 588                 /* For STARTTLS: Don't try and init a session on a socket that already has a session */
 589                 if (session->sess)
 590                         return;
 591
 592                 InitSession(user, true);
 593         }
 594
 595         void OnStreamSocketConnect(StreamSocket* user) CXX11_OVERRIDE
 596         {
 597                 InitSession(user, false);
 598         }
 599
 600         void OnStreamSocketClose(StreamSocket* user) CXX11_OVERRIDE
 601         {
 602                 CloseSession(&sessions[user->GetFd()]);
 603         }
 604
 605         int OnStreamSocketRead(StreamSocket* user, std::string& recvq) CXX11_OVERRIDE
 606         {
 607                 issl_session* session = &sessions[user->GetFd()];
 608
 609                 if (!session->sess)
 610                 {
 611                         CloseSession(session);
 612                         user->SetError("No SSL session");
 613                         return -1;
 614                 }
 615
 616                 if (session->status == ISSL_HANDSHAKING_READ || session->status == ISSL_HANDSHAKING_WRITE)
 617                 {
 618                         // The handshake isn't finished, try to finish it.
 619
 620                         if(!Handshake(session, user))
 621                         {
 622                                 if (session->status != ISSL_CLOSING)
 623                                         return 0;
 624                                 return -1;
 625                         }
 626                 }
 627
 628                 // If we resumed the handshake then session->status will be ISSL_HANDSHAKEN.
 629
 630                 if (session->status == ISSL_HANDSHAKEN)
 631                 {
 632                         char* buffer = ServerInstance->GetReadBuffer();
 633                         size_t bufsiz = ServerInstance->Config->NetBufferSize;
 634                         int ret = gnutls_record_recv(session->sess, buffer, bufsiz);
 635                         if (ret > 0)
 636                         {
 637                                 recvq.append(buffer, ret);
 638                                 return 1;
 639                         }
 640                         else if (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED)
 641                         {
 642                                 return 0;
 643                         }
 644                         else if (ret == 0)
 645                         {
 646                                 user->SetError("Connection closed");
 647                                 CloseSession(session);
 648                                 return -1;
 649                         }
 650                         else
 651                         {
 652                                 user->SetError(gnutls_strerror(ret));
 653                                 CloseSession(session);
 654                                 return -1;
 655                         }
 656                 }
 657                 else if (session->status == ISSL_CLOSING)
 658                         return -1;
 659
 660                 return 0;
 661         }
 662
 663         int OnStreamSocketWrite(StreamSocket* user, std::string& sendq) CXX11_OVERRIDE
 664         {
 665                 issl_session* session = &sessions[user->GetFd()];
 666
 667                 if (!session->sess)
 668                 {
 669                         CloseSession(session);
 670                         user->SetError("No SSL session");
 671                         return -1;
 672                 }
 673
 674                 if (session->status == ISSL_HANDSHAKING_WRITE || session->status == ISSL_HANDSHAKING_READ)
 675                 {
 676                         // The handshake isn't finished, try to finish it.
 677                         Handshake(session, user);
 678                         if (session->status != ISSL_CLOSING)
 679                                 return 0;
 680                         return -1;
 681                 }
 682
 683                 int ret = 0;
 684
 685                 if (session->status == ISSL_HANDSHAKEN)
 686                 {
 687                         ret = gnutls_record_send(session->sess, sendq.data(), sendq.length());
 688
 689                         if (ret == (int)sendq.length())
 690                         {
 691                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_NO_WRITE);
 692                                 return 1;
 693                         }
 694                         else if (ret > 0)
 695                         {
 696                                 sendq = sendq.substr(ret);
 697                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_SINGLE_WRITE);
 698                                 return 0;
 699                         }
 700                         else if (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED || ret == 0)
 701                         {
 702                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_SINGLE_WRITE);
 703                                 return 0;
 704                         }
 705                         else // (ret < 0)
 706                         {
 707                                 user->SetError(gnutls_strerror(ret));
 708                                 CloseSession(session);
 709                                 return -1;
 710                         }
 711                 }
 712
 713                 return 0;
 714         }
 715
 716         bool Handshake(issl_session* session, StreamSocket* user)
 717         {
 718                 int ret = gnutls_handshake(session->sess);
 719
 720                 if (ret < 0)
 721                 {
 722                         if(ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED)
 723                         {
 724                                 // Handshake needs resuming later, read() or write() would have blocked.
 725
 726                                 if(gnutls_record_get_direction(session->sess) == 0)
 727                                 {
 728                                         // gnutls_handshake() wants to read() again.
 729                                         session->status = ISSL_HANDSHAKING_READ;
 730                                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_POLL_READ | FD_WANT_NO_WRITE);
 731                                 }
 732                                 else
 733                                 {
 734                                         // gnutls_handshake() wants to write() again.
 735                                         session->status = ISSL_HANDSHAKING_WRITE;
 736                                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_NO_READ | FD_WANT_SINGLE_WRITE);
 737                                 }
 738                         }
 739                         else
 740                         {
 741                                 user->SetError("Handshake Failed - " + std::string(gnutls_strerror(ret)));
 742                                 CloseSession(session);
 743                                 session->status = ISSL_CLOSING;
 744                         }
 745
 746                         return false;
 747                 }
 748                 else
 749                 {
 750                         // Change the seesion state
 751                         session->status = ISSL_HANDSHAKEN;
 752
 753                         VerifyCertificate(session,user);
 754
 755                         // Finish writing, if any left
 756                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_POLL_READ | FD_WANT_NO_WRITE | FD_ADD_TRIAL_WRITE);
 757
 758                         return true;
 759                 }
 760         }
 761
 762         void OnUserConnect(LocalUser* user) CXX11_OVERRIDE
 763         {
 764                 if (user->eh.GetIOHook() == this)
 765                 {
 766                         if (sessions[user->eh.GetFd()].sess)
 767                         {
 768                                 const gnutls_session_t& sess = sessions[user->eh.GetFd()].sess;
 769                                 std::string cipher = UnknownIfNULL(gnutls_kx_get_name(gnutls_kx_get(sess)));
 770                                 cipher.append("-").append(UnknownIfNULL(gnutls_cipher_get_name(gnutls_cipher_get(sess)))).append("-");
 771                                 cipher.append(UnknownIfNULL(gnutls_mac_get_name(gnutls_mac_get(sess))));
 772
 773                                 ssl_cert* cert = sessions[user->eh.GetFd()].cert;
 774                                 if (cert->fingerprint.empty())
 775                                         user->WriteNotice("*** You are connected using SSL cipher '" + cipher + "'");
 776                                 else
 777                                         user->WriteNotice("*** You are connected using SSL cipher '" + cipher +
 778                                                 "' and your SSL fingerprint is " + cert->fingerprint);
 779                         }
 780                 }
 781         }
 782
 783         void CloseSession(issl_session* session)
 784         {
 785                 if (session->sess)
 786                 {
 787                         gnutls_bye(session->sess, GNUTLS_SHUT_WR);
 788                         gnutls_deinit(session->sess);
 789                 }
 790                 session->socket = NULL;
 791                 session->sess = NULL;
 792                 session->cert = NULL;
 793                 session->status = ISSL_NONE;
 794         }
 795
 796         void VerifyCertificate(issl_session* session, StreamSocket* user)
 797         {
 798                 if (!session->sess || !user)
 799                         return;
 800
 801                 unsigned int status;
 802                 const gnutls_datum_t* cert_list;
 803                 int ret;
 804                 unsigned int cert_list_size;
 805                 gnutls_x509_crt_t cert;
 806                 char name[MAXBUF];
 807                 unsigned char digest[MAXBUF];
 808                 size_t digest_size = sizeof(digest);
 809                 size_t name_size = sizeof(name);
 810                 ssl_cert* certinfo = new ssl_cert;
 811                 session->cert = certinfo;
 812
 813                 /* This verification function uses the trusted CAs in the credentials
 814                  * structure. So you must have installed one or more CA certificates.
 815                  */
 816                 ret = gnutls_certificate_verify_peers2(session->sess, &status);
 817
 818                 if (ret < 0)
 819                 {
 820                         certinfo->error = std::string(gnutls_strerror(ret));
 821                         return;
 822                 }
 823
 824                 certinfo->invalid = (status & GNUTLS_CERT_INVALID);
 825                 certinfo->unknownsigner = (status & GNUTLS_CERT_SIGNER_NOT_FOUND);
 826                 certinfo->revoked = (status & GNUTLS_CERT_REVOKED);
 827                 certinfo->trusted = !(status & GNUTLS_CERT_SIGNER_NOT_CA);
 828
 829                 /* Up to here the process is the same for X.509 certificates and
 830                  * OpenPGP keys. From now on X.509 certificates are assumed. This can
 831                  * be easily extended to work with openpgp keys as well.
 832                  */
 833                 if (gnutls_certificate_type_get(session->sess) != GNUTLS_CRT_X509)
 834                 {
 835                         certinfo->error = "No X509 keys sent";
 836                         return;
 837                 }
 838
 839                 ret = gnutls_x509_crt_init(&cert);
 840                 if (ret < 0)
 841                 {
 842                         certinfo->error = gnutls_strerror(ret);
 843                         return;
 844                 }
 845
 846                 cert_list_size = 0;
 847                 cert_list = gnutls_certificate_get_peers(session->sess, &cert_list_size);
 848                 if (cert_list == NULL)
 849                 {
 850                         certinfo->error = "No certificate was found";
 851                         goto info_done_dealloc;
 852                 }
 853
 854                 /* This is not a real world example, since we only check the first
 855                  * certificate in the given chain.
 856                  */
 857
 858                 ret = gnutls_x509_crt_import(cert, &cert_list[0], GNUTLS_X509_FMT_DER);
 859                 if (ret < 0)
 860                 {
 861                         certinfo->error = gnutls_strerror(ret);
 862                         goto info_done_dealloc;
 863                 }
 864
 865                 gnutls_x509_crt_get_dn(cert, name, &name_size);
 866                 certinfo->dn = name;
 867
 868                 gnutls_x509_crt_get_issuer_dn(cert, name, &name_size);
 869                 certinfo->issuer = name;
 870
 871                 if ((ret = gnutls_x509_crt_get_fingerprint(cert, hash, digest, &digest_size)) < 0)
 872                 {
 873                         certinfo->error = gnutls_strerror(ret);
 874                 }
 875                 else
 876                 {
 877                         certinfo->fingerprint = BinToHex(digest, digest_size);
 878                 }
 879
 880                 /* Beware here we do not check for errors.
 881                  */
 882                 if ((gnutls_x509_crt_get_expiration_time(cert) < ServerInstance->Time()) || (gnutls_x509_crt_get_activation_time(cert) > ServerInstance->Time()))
 883                 {
 884                         certinfo->error = "Not activated, or expired certificate";
 885                 }
 886
 887 info_done_dealloc:
 888                 gnutls_x509_crt_deinit(cert);
 889         }
 890
 891         void OnEvent(Event& ev) CXX11_OVERRIDE
 892         {
 893                 if (starttls.enabled)
 894                         capHandler.HandleEvent(ev);
 895         }
 896 };
 897
 898 MODULE_INIT(ModuleSSLGnuTLS)