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 <gnutls/gnutls.h>
  26 #include <gnutls/x509.h>
  27 #include <gcrypt.h>
  28 #include "ssl.h"
  29 #include "m_cap.h"
  30
  31 #ifdef WINDOWS
  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","") -Wno-deprecated-declarations */
  44 /* $LinkerFlags: rpath("pkg-config --libs gnutls") pkgconflibs("gnutls","/libgnutls.so","-lgnutls") -lgcrypt */
  45
  46 enum issl_status { ISSL_NONE, ISSL_HANDSHAKING_READ, ISSL_HANDSHAKING_WRITE, ISSL_HANDSHAKEN, ISSL_CLOSING, ISSL_CLOSED };
  47
  48 static std::vector<gnutls_x509_crt_t> x509_certs;
  49 static gnutls_x509_privkey_t x509_key;
  50 static int cert_callback (gnutls_session_t session, const gnutls_datum_t * req_ca_rdn, int nreqs,
  51         const gnutls_pk_algorithm_t * sign_algos, int sign_algos_length, gnutls_retr_st * st) {
  52
  53         st->type = GNUTLS_CRT_X509;
  54         st->ncerts = x509_certs.size();
  55         st->cert.x509 = &x509_certs[0];
  56         st->key.x509 = x509_key;
  57         st->deinit_all = 0;
  58
  59         return 0;
  60 }
  61
  62 static ssize_t gnutls_pull_wrapper(gnutls_transport_ptr_t user_wrap, void* buffer, size_t size)
  63 {
  64         StreamSocket* user = reinterpret_cast<StreamSocket*>(user_wrap);
  65         if (user->GetEventMask() & FD_READ_WILL_BLOCK)
  66         {
  67                 errno = EAGAIN;
  68                 return -1;
  69         }
  70         int rv = ServerInstance->SE->Recv(user, reinterpret_cast<char *>(buffer), size, 0);
  71         if (rv < (int)size)
  72                 ServerInstance->SE->ChangeEventMask(user, FD_READ_WILL_BLOCK);
  73         return rv;
  74 }
  75
  76 static ssize_t gnutls_push_wrapper(gnutls_transport_ptr_t user_wrap, const void* buffer, size_t size)
  77 {
  78         StreamSocket* user = reinterpret_cast<StreamSocket*>(user_wrap);
  79         if (user->GetEventMask() & FD_WRITE_WILL_BLOCK)
  80         {
  81                 errno = EAGAIN;
  82                 return -1;
  83         }
  84         int rv = ServerInstance->SE->Send(user, reinterpret_cast<const char *>(buffer), size, 0);
  85         if (rv < (int)size)
  86                 ServerInstance->SE->ChangeEventMask(user, FD_WRITE_WILL_BLOCK);
  87         return rv;
  88 }
  89
  90 class RandGen : public HandlerBase2<void, char*, size_t>
  91 {
  92  public:
  93         RandGen() {}
  94         void Call(char* buffer, size_t len)
  95         {
  96                 gcry_randomize(buffer, len, GCRY_STRONG_RANDOM);
  97         }
  98 };
  99
 100 /** Represents an SSL user's extra data
 101  */
 102 class issl_session
 103 {
 104 public:
 105         gnutls_session_t sess;
 106         issl_status status;
 107         reference<ssl_cert> cert;
 108         issl_session() : sess(NULL) {}
 109 };
 110
 111 class CommandStartTLS : public SplitCommand
 112 {
 113  public:
 114         bool enabled;
 115         CommandStartTLS (Module* mod) : SplitCommand(mod, "STARTTLS")
 116         {
 117                 enabled = true;
 118                 works_before_reg = true;
 119         }
 120
 121         CmdResult HandleLocal(const std::vector<std::string> &parameters, LocalUser *user)
 122         {
 123                 if (!enabled)
 124                 {
 125                         user->WriteNumeric(691, "%s :STARTTLS is not enabled", user->nick.c_str());
 126                         return CMD_FAILURE;
 127                 }
 128
 129                 if (user->registered == REG_ALL)
 130                 {
 131                         user->WriteNumeric(691, "%s :STARTTLS is not permitted after client registration is complete", user->nick.c_str());
 132                 }
 133                 else
 134                 {
 135                         if (!user->eh.GetIOHook())
 136                         {
 137                                 user->WriteNumeric(670, "%s :STARTTLS successful, go ahead with TLS handshake", user->nick.c_str());
 138                                 /* We need to flush the write buffer prior to adding the IOHook,
 139                                  * otherwise we'll be sending this line inside the SSL session - which
 140                                  * won't start its handshake until the client gets this line. Currently,
 141                                  * we assume the write will not block here; this is usually safe, as
 142                                  * STARTTLS is sent very early on in the registration phase, where the
 143                                  * user hasn't built up much sendq. Handling a blocked write here would
 144                                  * be very annoying.
 145                                  */
 146                                 user->eh.DoWrite();
 147                                 user->eh.AddIOHook(creator);
 148                                 creator->OnStreamSocketAccept(&user->eh, NULL, NULL);
 149                         }
 150                         else
 151                                 user->WriteNumeric(691, "%s :STARTTLS failure", user->nick.c_str());
 152                 }
 153
 154                 return CMD_FAILURE;
 155         }
 156 };
 157
 158 class ModuleSSLGnuTLS : public Module
 159 {
 160         issl_session* sessions;
 161
 162         gnutls_certificate_credentials x509_cred;
 163         gnutls_dh_params dh_params;
 164         gnutls_digest_algorithm_t hash;
 165
 166         std::string sslports;
 167         int dh_bits;
 168
 169         bool cred_alloc;
 170         bool dh_alloc;
 171
 172         RandGen randhandler;
 173         CommandStartTLS starttls;
 174
 175         GenericCap capHandler;
 176         ServiceProvider iohook;
 177  public:
 178
 179         ModuleSSLGnuTLS()
 180                 : starttls(this), capHandler(this, "tls"), iohook(this, "ssl/gnutls", SERVICE_IOHOOK)
 181         {
 182                 sessions = new issl_session[ServerInstance->SE->GetMaxFds()];
 183
 184                 gnutls_global_init(); // This must be called once in the program
 185                 gnutls_x509_privkey_init(&x509_key);
 186
 187                 cred_alloc = false;
 188                 dh_alloc = false;
 189         }
 190
 191         void init()
 192         {
 193                 // Needs the flag as it ignores a plain /rehash
 194                 OnModuleRehash(NULL,"ssl");
 195
 196                 ServerInstance->GenRandom = &randhandler;
 197
 198                 // Void return, guess we assume success
 199                 gnutls_certificate_set_dh_params(x509_cred, dh_params);
 200                 Implementation eventlist[] = { I_On005Numeric, I_OnRehash, I_OnModuleRehash, I_OnUserConnect,
 201                         I_OnEvent, I_OnHookIO };
 202                 ServerInstance->Modules->Attach(eventlist, this, sizeof(eventlist)/sizeof(Implementation));
 203
 204                 ServerInstance->Modules->AddService(iohook);
 205                 ServerInstance->AddCommand(&starttls);
 206         }
 207
 208         void OnRehash(User* user)
 209         {
 210                 sslports.clear();
 211
 212                 ConfigTag* Conf = ServerInstance->Config->ConfValue("gnutls");
 213                 starttls.enabled = Conf->getBool("starttls", true);
 214
 215                 if (Conf->getBool("showports", true))
 216                 {
 217                         sslports = Conf->getString("advertisedports");
 218                         if (!sslports.empty())
 219                                 return;
 220
 221                         for (size_t i = 0; i < ServerInstance->ports.size(); i++)
 222                         {
 223                                 ListenSocket* port = ServerInstance->ports[i];
 224                                 if (port->bind_tag->getString("ssl") != "gnutls")
 225                                         continue;
 226
 227                                 const std::string& portid = port->bind_desc;
 228                                 ServerInstance->Logs->Log("m_ssl_gnutls", DEFAULT, "m_ssl_gnutls.so: Enabling SSL for port %s", portid.c_str());
 229
 230                                 if (port->bind_tag->getString("type", "clients") == "clients" && port->bind_addr != "127.0.0.1")
 231                                 {
 232                                         /*
 233                                          * Found an SSL port for clients that is not bound to 127.0.0.1 and handled by us, display
 234                                          * the IP:port in ISUPPORT.
 235                                          *
 236                                          * We used to advertise all ports seperated by a ';' char that matched the above criteria,
 237                                          * but this resulted in too long ISUPPORT lines if there were lots of ports to be displayed.
 238                                          * To solve this by default we now only display the first IP:port found and let the user
 239                                          * configure the exact value for the 005 token, if necessary.
 240                                          */
 241                                         sslports = portid;
 242                                         break;
 243                                 }
 244                         }
 245                 }
 246         }
 247
 248         void OnModuleRehash(User* user, const std::string &param)
 249         {
 250                 if(param != "ssl")
 251                         return;
 252
 253                 std::string keyfile;
 254                 std::string certfile;
 255                 std::string cafile;
 256                 std::string crlfile;
 257                 OnRehash(user);
 258
 259                 ConfigTag* Conf = ServerInstance->Config->ConfValue("gnutls");
 260
 261                 cafile = Conf->getString("cafile", "conf/ca.pem");
 262                 crlfile = Conf->getString("crlfile", "conf/crl.pem");
 263                 certfile = Conf->getString("certfile", "conf/cert.pem");
 264                 keyfile = Conf->getString("keyfile", "conf/key.pem");
 265                 dh_bits = Conf->getInt("dhbits");
 266                 std::string hashname = Conf->getString("hash", "md5");
 267
 268                 if((dh_bits != 768) && (dh_bits != 1024) && (dh_bits != 2048) && (dh_bits != 3072) && (dh_bits != 4096))
 269                         dh_bits = 1024;
 270
 271                 if (hashname == "md5")
 272                         hash = GNUTLS_DIG_MD5;
 273                 else if (hashname == "sha1")
 274                         hash = GNUTLS_DIG_SHA1;
 275                 else
 276                         throw ModuleException("Unknown hash type " + hashname);
 277
 278
 279                 int ret;
 280
 281                 if (dh_alloc)
 282                 {
 283                         gnutls_dh_params_deinit(dh_params);
 284                         dh_alloc = false;
 285                 }
 286
 287                 if (cred_alloc)
 288                 {
 289                         // Deallocate the old credentials
 290                         gnutls_certificate_free_credentials(x509_cred);
 291
 292                         for(unsigned int i=0; i < x509_certs.size(); i++)
 293                                 gnutls_x509_crt_deinit(x509_certs[i]);
 294                         x509_certs.clear();
 295                 }
 296
 297                 ret = gnutls_certificate_allocate_credentials(&x509_cred);
 298                 cred_alloc = (ret >= 0);
 299                 if (!cred_alloc)
 300                         ServerInstance->Logs->Log("m_ssl_gnutls",DEBUG, "m_ssl_gnutls.so: Failed to allocate certificate credentials: %s", gnutls_strerror(ret));
 301
 302                 if((ret =gnutls_certificate_set_x509_trust_file(x509_cred, cafile.c_str(), GNUTLS_X509_FMT_PEM)) < 0)
 303                         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));
 304
 305                 if((ret = gnutls_certificate_set_x509_crl_file (x509_cred, crlfile.c_str(), GNUTLS_X509_FMT_PEM)) < 0)
 306                         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));
 307
 308                 FileReader reader;
 309
 310                 reader.LoadFile(certfile);
 311                 std::string cert_string = reader.Contents();
 312                 gnutls_datum_t cert_datum = { (unsigned char*)cert_string.data(), cert_string.length() };
 313
 314                 reader.LoadFile(keyfile);
 315                 std::string key_string = reader.Contents();
 316                 gnutls_datum_t key_datum = { (unsigned char*)key_string.data(), key_string.length() };
 317
 318                 // If this fails, no SSL port will work. At all. So, do the smart thing - throw a ModuleException
 319                 unsigned int certcount = Conf->getInt("certcount", 3);
 320                 x509_certs.resize(certcount);
 321                 ret = gnutls_x509_crt_list_import(&x509_certs[0], &certcount, &cert_datum, GNUTLS_X509_FMT_PEM, GNUTLS_X509_CRT_LIST_IMPORT_FAIL_IF_EXCEED);
 322                 if (ret < 0)
 323                         throw ModuleException("Unable to load GnuTLS server certificate (" + certfile + "): " + std::string(gnutls_strerror(ret)));
 324                 x509_certs.resize(certcount);
 325
 326                 if((ret = gnutls_x509_privkey_import(x509_key, &key_datum, GNUTLS_X509_FMT_PEM)) < 0)
 327                         throw ModuleException("Unable to load GnuTLS server private key (" + keyfile + "): " + std::string(gnutls_strerror(ret)));
 328
 329                 if((ret = gnutls_certificate_set_x509_key(x509_cred, &x509_certs[0], certcount, x509_key)) < 0)
 330                         throw ModuleException("Unable to set GnuTLS cert/key pair: " + std::string(gnutls_strerror(ret)));
 331
 332                 gnutls_certificate_client_set_retrieve_function (x509_cred, cert_callback);
 333
 334                 ret = gnutls_dh_params_init(&dh_params);
 335                 dh_alloc = (ret >= 0);
 336                 if (!dh_alloc)
 337                         ServerInstance->Logs->Log("m_ssl_gnutls",DEFAULT, "m_ssl_gnutls.so: Failed to initialise DH parameters: %s", gnutls_strerror(ret));
 338
 339                 // This may be on a large (once a day or week) timer eventually.
 340                 GenerateDHParams();
 341         }
 342
 343         void GenerateDHParams()
 344         {
 345                 // Generate Diffie Hellman parameters - for use with DHE
 346                 // kx algorithms. These should be discarded and regenerated
 347                 // once a day, once a week or once a month. Depending on the
 348                 // security requirements.
 349
 350                 if (!dh_alloc)
 351                         return;
 352
 353                 int ret;
 354
 355                 if((ret = gnutls_dh_params_generate2(dh_params, dh_bits)) < 0)
 356                         ServerInstance->Logs->Log("m_ssl_gnutls",DEFAULT, "m_ssl_gnutls.so: Failed to generate DH parameters (%d bits): %s", dh_bits, gnutls_strerror(ret));
 357         }
 358
 359         ~ModuleSSLGnuTLS()
 360         {
 361                 for(unsigned int i=0; i < x509_certs.size(); i++)
 362                         gnutls_x509_crt_deinit(x509_certs[i]);
 363
 364                 gnutls_x509_privkey_deinit(x509_key);
 365
 366                 if (dh_alloc)
 367                         gnutls_dh_params_deinit(dh_params);
 368                 if (cred_alloc)
 369                         gnutls_certificate_free_credentials(x509_cred);
 370
 371                 gnutls_global_deinit();
 372                 delete[] sessions;
 373                 ServerInstance->GenRandom = &ServerInstance->HandleGenRandom;
 374         }
 375
 376         void OnCleanup(int target_type, void* item)
 377         {
 378                 if(target_type == TYPE_USER)
 379                 {
 380                         LocalUser* user = IS_LOCAL(static_cast<User*>(item));
 381
 382                         if (user && user->eh.GetIOHook() == this)
 383                         {
 384                                 // User is using SSL, they're a local user, and they're using one of *our* SSL ports.
 385                                 // Potentially there could be multiple SSL modules loaded at once on different ports.
 386                                 ServerInstance->Users->QuitUser(user, "SSL module unloading");
 387                         }
 388                 }
 389         }
 390
 391         Version GetVersion()
 392         {
 393                 return Version("Provides SSL support for clients", VF_VENDOR);
 394         }
 395
 396
 397         void On005Numeric(std::string &output)
 398         {
 399                 if (!sslports.empty())
 400                         output.append(" SSL=" + sslports);
 401                 if (starttls.enabled)
 402                         output.append(" STARTTLS");
 403         }
 404
 405         void OnHookIO(StreamSocket* user, ListenSocket* lsb)
 406         {
 407                 if (!user->GetIOHook() && lsb->bind_tag->getString("ssl") == "gnutls")
 408                 {
 409                         /* Hook the user with our module */
 410                         user->AddIOHook(this);
 411                 }
 412         }
 413
 414         void OnRequest(Request& request)
 415         {
 416                 if (strcmp("GET_SSL_CERT", request.id) == 0)
 417                 {
 418                         SocketCertificateRequest& req = static_cast<SocketCertificateRequest&>(request);
 419                         int fd = req.sock->GetFd();
 420                         issl_session* session = &sessions[fd];
 421
 422                         req.cert = session->cert;
 423                 }
 424         }
 425
 426         void InitSession(StreamSocket* user, bool me_server)
 427         {
 428                 issl_session* session = &sessions[user->GetFd()];
 429
 430                 gnutls_init(&session->sess, me_server ? GNUTLS_SERVER : GNUTLS_CLIENT);
 431
 432                 gnutls_set_default_priority(session->sess); // Avoid calling all the priority functions, defaults are adequate.
 433                 gnutls_credentials_set(session->sess, GNUTLS_CRD_CERTIFICATE, x509_cred);
 434                 gnutls_dh_set_prime_bits(session->sess, dh_bits);
 435                 gnutls_transport_set_ptr(session->sess, reinterpret_cast<gnutls_transport_ptr_t>(user));
 436                 gnutls_transport_set_push_function(session->sess, gnutls_push_wrapper);
 437                 gnutls_transport_set_pull_function(session->sess, gnutls_pull_wrapper);
 438
 439                 if (me_server)
 440                         gnutls_certificate_server_set_request(session->sess, GNUTLS_CERT_REQUEST); // Request client certificate if any.
 441
 442                 Handshake(session, user);
 443         }
 444
 445         void OnStreamSocketAccept(StreamSocket* user, irc::sockets::sockaddrs* client, irc::sockets::sockaddrs* server)
 446         {
 447                 issl_session* session = &sessions[user->GetFd()];
 448
 449                 /* For STARTTLS: Don't try and init a session on a socket that already has a session */
 450                 if (session->sess)
 451                         return;
 452
 453                 InitSession(user, true);
 454         }
 455
 456         void OnStreamSocketConnect(StreamSocket* user)
 457         {
 458                 InitSession(user, false);
 459         }
 460
 461         void OnStreamSocketClose(StreamSocket* user)
 462         {
 463                 CloseSession(&sessions[user->GetFd()]);
 464         }
 465
 466         int OnStreamSocketRead(StreamSocket* user, std::string& recvq)
 467         {
 468                 issl_session* session = &sessions[user->GetFd()];
 469
 470                 if (!session->sess)
 471                 {
 472                         CloseSession(session);
 473                         user->SetError("No SSL session");
 474                         return -1;
 475                 }
 476
 477                 if (session->status == ISSL_HANDSHAKING_READ || session->status == ISSL_HANDSHAKING_WRITE)
 478                 {
 479                         // The handshake isn't finished, try to finish it.
 480
 481                         if(!Handshake(session, user))
 482                         {
 483                                 if (session->status != ISSL_CLOSING)
 484                                         return 0;
 485                                 return -1;
 486                         }
 487                 }
 488
 489                 // If we resumed the handshake then session->status will be ISSL_HANDSHAKEN.
 490
 491                 if (session->status == ISSL_HANDSHAKEN)
 492                 {
 493                         char* buffer = ServerInstance->GetReadBuffer();
 494                         size_t bufsiz = ServerInstance->Config->NetBufferSize;
 495                         int ret = gnutls_record_recv(session->sess, buffer, bufsiz);
 496                         if (ret > 0)
 497                         {
 498                                 recvq.append(buffer, ret);
 499                                 return 1;
 500                         }
 501                         else if (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED)
 502                         {
 503                                 return 0;
 504                         }
 505                         else if (ret == 0)
 506                         {
 507                                 user->SetError("SSL Connection closed");
 508                                 CloseSession(session);
 509                                 return -1;
 510                         }
 511                         else
 512                         {
 513                                 user->SetError(gnutls_strerror(ret));
 514                                 CloseSession(session);
 515                                 return -1;
 516                         }
 517                 }
 518                 else if (session->status == ISSL_CLOSING)
 519                         return -1;
 520
 521                 return 0;
 522         }
 523
 524         int OnStreamSocketWrite(StreamSocket* user, std::string& sendq)
 525         {
 526                 issl_session* session = &sessions[user->GetFd()];
 527
 528                 if (!session->sess)
 529                 {
 530                         CloseSession(session);
 531                         user->SetError("No SSL session");
 532                         return -1;
 533                 }
 534
 535                 if (session->status == ISSL_HANDSHAKING_WRITE || session->status == ISSL_HANDSHAKING_READ)
 536                 {
 537                         // The handshake isn't finished, try to finish it.
 538                         Handshake(session, user);
 539                         if (session->status != ISSL_CLOSING)
 540                                 return 0;
 541                         return -1;
 542                 }
 543
 544                 int ret = 0;
 545
 546                 if (session->status == ISSL_HANDSHAKEN)
 547                 {
 548                         ret = gnutls_record_send(session->sess, sendq.data(), sendq.length());
 549
 550                         if (ret == (int)sendq.length())
 551                         {
 552                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_NO_WRITE);
 553                                 return 1;
 554                         }
 555                         else if (ret > 0)
 556                         {
 557                                 sendq = sendq.substr(ret);
 558                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_SINGLE_WRITE);
 559                                 return 0;
 560                         }
 561                         else if (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED || ret == 0)
 562                         {
 563                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_SINGLE_WRITE);
 564                                 return 0;
 565                         }
 566                         else // (ret < 0)
 567                         {
 568                                 user->SetError(gnutls_strerror(ret));
 569                                 CloseSession(session);
 570                                 return -1;
 571                         }
 572                 }
 573
 574                 return 0;
 575         }
 576
 577         bool Handshake(issl_session* session, StreamSocket* user)
 578         {
 579                 int ret = gnutls_handshake(session->sess);
 580
 581                 if (ret < 0)
 582                 {
 583                         if(ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED)
 584                         {
 585                                 // Handshake needs resuming later, read() or write() would have blocked.
 586
 587                                 if(gnutls_record_get_direction(session->sess) == 0)
 588                                 {
 589                                         // gnutls_handshake() wants to read() again.
 590                                         session->status = ISSL_HANDSHAKING_READ;
 591                                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_POLL_READ | FD_WANT_NO_WRITE);
 592                                 }
 593                                 else
 594                                 {
 595                                         // gnutls_handshake() wants to write() again.
 596                                         session->status = ISSL_HANDSHAKING_WRITE;
 597                                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_NO_READ | FD_WANT_SINGLE_WRITE);
 598                                 }
 599                         }
 600                         else
 601                         {
 602                                 user->SetError(std::string("Handshake Failed - ") + gnutls_strerror(ret));
 603                                 CloseSession(session);
 604                                 session->status = ISSL_CLOSING;
 605                         }
 606
 607                         return false;
 608                 }
 609                 else
 610                 {
 611                         // Change the seesion state
 612                         session->status = ISSL_HANDSHAKEN;
 613
 614                         VerifyCertificate(session,user);
 615
 616                         // Finish writing, if any left
 617                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_POLL_READ | FD_WANT_NO_WRITE | FD_ADD_TRIAL_WRITE);
 618
 619                         return true;
 620                 }
 621         }
 622
 623         void OnUserConnect(LocalUser* user)
 624         {
 625                 if (user->eh.GetIOHook() == this)
 626                 {
 627                         if (sessions[user->eh.GetFd()].sess)
 628                         {
 629                                 ssl_cert* cert = sessions[user->eh.GetFd()].cert;
 630                                 std::string cipher = gnutls_kx_get_name(gnutls_kx_get(sessions[user->eh.GetFd()].sess));
 631                                 cipher.append("-").append(gnutls_cipher_get_name(gnutls_cipher_get(sessions[user->eh.GetFd()].sess))).append("-");
 632                                 cipher.append(gnutls_mac_get_name(gnutls_mac_get(sessions[user->eh.GetFd()].sess)));
 633                                 if (cert->fingerprint.empty())
 634                                         user->WriteServ("NOTICE %s :*** You are connected using SSL cipher \"%s\"", user->nick.c_str(), cipher.c_str());
 635                                 else
 636                                         user->WriteServ("NOTICE %s :*** You are connected using SSL cipher \"%s\""
 637                                                 " and your SSL fingerprint is %s", user->nick.c_str(), cipher.c_str(), cert->fingerprint.c_str());
 638                         }
 639                 }
 640         }
 641
 642         void CloseSession(issl_session* session)
 643         {
 644                 if (session->sess)
 645                 {
 646                         gnutls_bye(session->sess, GNUTLS_SHUT_WR);
 647                         gnutls_deinit(session->sess);
 648                 }
 649                 session->sess = NULL;
 650                 session->cert = NULL;
 651                 session->status = ISSL_NONE;
 652         }
 653
 654         void VerifyCertificate(issl_session* session, StreamSocket* user)
 655         {
 656                 if (!session->sess || !user)
 657                         return;
 658
 659                 unsigned int status;
 660                 const gnutls_datum_t* cert_list;
 661                 int ret;
 662                 unsigned int cert_list_size;
 663                 gnutls_x509_crt_t cert;
 664                 char name[MAXBUF];
 665                 unsigned char digest[MAXBUF];
 666                 size_t digest_size = sizeof(digest);
 667                 size_t name_size = sizeof(name);
 668                 ssl_cert* certinfo = new ssl_cert;
 669                 session->cert = certinfo;
 670
 671                 /* This verification function uses the trusted CAs in the credentials
 672                  * structure. So you must have installed one or more CA certificates.
 673                  */
 674                 ret = gnutls_certificate_verify_peers2(session->sess, &status);
 675
 676                 if (ret < 0)
 677                 {
 678                         certinfo->error = std::string(gnutls_strerror(ret));
 679                         return;
 680                 }
 681
 682                 certinfo->invalid = (status & GNUTLS_CERT_INVALID);
 683                 certinfo->unknownsigner = (status & GNUTLS_CERT_SIGNER_NOT_FOUND);
 684                 certinfo->revoked = (status & GNUTLS_CERT_REVOKED);
 685                 certinfo->trusted = !(status & GNUTLS_CERT_SIGNER_NOT_CA);
 686
 687                 /* Up to here the process is the same for X.509 certificates and
 688                  * OpenPGP keys. From now on X.509 certificates are assumed. This can
 689                  * be easily extended to work with openpgp keys as well.
 690                  */
 691                 if (gnutls_certificate_type_get(session->sess) != GNUTLS_CRT_X509)
 692                 {
 693                         certinfo->error = "No X509 keys sent";
 694                         return;
 695                 }
 696
 697                 ret = gnutls_x509_crt_init(&cert);
 698                 if (ret < 0)
 699                 {
 700                         certinfo->error = gnutls_strerror(ret);
 701                         return;
 702                 }
 703
 704                 cert_list_size = 0;
 705                 cert_list = gnutls_certificate_get_peers(session->sess, &cert_list_size);
 706                 if (cert_list == NULL)
 707                 {
 708                         certinfo->error = "No certificate was found";
 709                         goto info_done_dealloc;
 710                 }
 711
 712                 /* This is not a real world example, since we only check the first
 713                  * certificate in the given chain.
 714                  */
 715
 716                 ret = gnutls_x509_crt_import(cert, &cert_list[0], GNUTLS_X509_FMT_DER);
 717                 if (ret < 0)
 718                 {
 719                         certinfo->error = gnutls_strerror(ret);
 720                         goto info_done_dealloc;
 721                 }
 722
 723                 gnutls_x509_crt_get_dn(cert, name, &name_size);
 724                 certinfo->dn = name;
 725
 726                 gnutls_x509_crt_get_issuer_dn(cert, name, &name_size);
 727                 certinfo->issuer = name;
 728
 729                 if ((ret = gnutls_x509_crt_get_fingerprint(cert, hash, digest, &digest_size)) < 0)
 730                 {
 731                         certinfo->error = gnutls_strerror(ret);
 732                 }
 733                 else
 734                 {
 735                         certinfo->fingerprint = irc::hex(digest, digest_size);
 736                 }
 737
 738                 /* Beware here we do not check for errors.
 739                  */
 740                 if ((gnutls_x509_crt_get_expiration_time(cert) < ServerInstance->Time()) || (gnutls_x509_crt_get_activation_time(cert) > ServerInstance->Time()))
 741                 {
 742                         certinfo->error = "Not activated, or expired certificate";
 743                 }
 744
 745 info_done_dealloc:
 746                 gnutls_x509_crt_deinit(cert);
 747         }
 748
 749         void OnEvent(Event& ev)
 750         {
 751                 if (starttls.enabled)
 752                         capHandler.HandleEvent(ev);
 753         }
 754 };
 755
 756 MODULE_INIT(ModuleSSLGnuTLS)