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         gnutls_priority_t priority;
 166
 167         std::string sslports;
 168         int dh_bits;
 169
 170         bool cred_alloc;
 171         bool dh_alloc;
 172
 173         RandGen randhandler;
 174         CommandStartTLS starttls;
 175
 176         GenericCap capHandler;
 177         ServiceProvider iohook;
 178  public:
 179
 180         ModuleSSLGnuTLS()
 181                 : starttls(this), capHandler(this, "tls"), iohook(this, "ssl/gnutls", SERVICE_IOHOOK)
 182         {
 183                 sessions = new issl_session[ServerInstance->SE->GetMaxFds()];
 184
 185                 gnutls_global_init(); // This must be called once in the program
 186                 gnutls_x509_privkey_init(&x509_key);
 187                 // Init this here so it's always initialized, avoids an extra boolean
 188                 gnutls_priority_init(&priority, "NORMAL", NULL);
 189
 190                 cred_alloc = false;
 191                 dh_alloc = false;
 192         }
 193
 194         void init()
 195         {
 196                 // Needs the flag as it ignores a plain /rehash
 197                 OnModuleRehash(NULL,"ssl");
 198
 199                 ServerInstance->GenRandom = &randhandler;
 200
 201                 // Void return, guess we assume success
 202                 gnutls_certificate_set_dh_params(x509_cred, dh_params);
 203                 Implementation eventlist[] = { I_On005Numeric, I_OnRehash, I_OnModuleRehash, I_OnUserConnect,
 204                         I_OnEvent, I_OnHookIO };
 205                 ServerInstance->Modules->Attach(eventlist, this, sizeof(eventlist)/sizeof(Implementation));
 206
 207                 ServerInstance->Modules->AddService(iohook);
 208                 ServerInstance->AddCommand(&starttls);
 209         }
 210
 211         void OnRehash(User* user)
 212         {
 213                 sslports.clear();
 214
 215                 ConfigTag* Conf = ServerInstance->Config->ConfValue("gnutls");
 216                 starttls.enabled = Conf->getBool("starttls", true);
 217
 218                 if (Conf->getBool("showports", true))
 219                 {
 220                         sslports = Conf->getString("advertisedports");
 221                         if (!sslports.empty())
 222                                 return;
 223
 224                         for (size_t i = 0; i < ServerInstance->ports.size(); i++)
 225                         {
 226                                 ListenSocket* port = ServerInstance->ports[i];
 227                                 if (port->bind_tag->getString("ssl") != "gnutls")
 228                                         continue;
 229
 230                                 const std::string& portid = port->bind_desc;
 231                                 ServerInstance->Logs->Log("m_ssl_gnutls", DEFAULT, "m_ssl_gnutls.so: Enabling SSL for port %s", portid.c_str());
 232
 233                                 if (port->bind_tag->getString("type", "clients") == "clients" && port->bind_addr != "127.0.0.1")
 234                                 {
 235                                         /*
 236                                          * Found an SSL port for clients that is not bound to 127.0.0.1 and handled by us, display
 237                                          * the IP:port in ISUPPORT.
 238                                          *
 239                                          * We used to advertise all ports seperated by a ';' char that matched the above criteria,
 240                                          * but this resulted in too long ISUPPORT lines if there were lots of ports to be displayed.
 241                                          * To solve this by default we now only display the first IP:port found and let the user
 242                                          * configure the exact value for the 005 token, if necessary.
 243                                          */
 244                                         sslports = portid;
 245                                         break;
 246                                 }
 247                         }
 248                 }
 249         }
 250
 251         void OnModuleRehash(User* user, const std::string &param)
 252         {
 253                 if(param != "ssl")
 254                         return;
 255
 256                 std::string keyfile;
 257                 std::string certfile;
 258                 std::string cafile;
 259                 std::string crlfile;
 260                 OnRehash(user);
 261
 262                 ConfigTag* Conf = ServerInstance->Config->ConfValue("gnutls");
 263
 264                 cafile = Conf->getString("cafile", "conf/ca.pem");
 265                 crlfile = Conf->getString("crlfile", "conf/crl.pem");
 266                 certfile = Conf->getString("certfile", "conf/cert.pem");
 267                 keyfile = Conf->getString("keyfile", "conf/key.pem");
 268                 dh_bits = Conf->getInt("dhbits");
 269                 std::string hashname = Conf->getString("hash", "md5");
 270
 271                 // The GnuTLS manual states that the gnutls_set_default_priority()
 272                 // call we used previously when initializing the session is the same
 273                 // as setting the "NORMAL" priority string.
 274                 // Thus if the setting below is not in the config we will behave exactly
 275                 // the same as before, when the priority setting wasn't available.
 276                 std::string priorities = Conf->getString("priority", "NORMAL");
 277
 278                 if((dh_bits != 768) && (dh_bits != 1024) && (dh_bits != 2048) && (dh_bits != 3072) && (dh_bits != 4096))
 279                         dh_bits = 1024;
 280
 281                 if (hashname == "md5")
 282                         hash = GNUTLS_DIG_MD5;
 283                 else if (hashname == "sha1")
 284                         hash = GNUTLS_DIG_SHA1;
 285                 else
 286                         throw ModuleException("Unknown hash type " + hashname);
 287
 288
 289                 int ret;
 290
 291                 if (dh_alloc)
 292                 {
 293                         gnutls_dh_params_deinit(dh_params);
 294                         dh_alloc = false;
 295                 }
 296
 297                 if (cred_alloc)
 298                 {
 299                         // Deallocate the old credentials
 300                         gnutls_certificate_free_credentials(x509_cred);
 301
 302                         for(unsigned int i=0; i < x509_certs.size(); i++)
 303                                 gnutls_x509_crt_deinit(x509_certs[i]);
 304                         x509_certs.clear();
 305                 }
 306
 307                 ret = gnutls_certificate_allocate_credentials(&x509_cred);
 308                 cred_alloc = (ret >= 0);
 309                 if (!cred_alloc)
 310                         ServerInstance->Logs->Log("m_ssl_gnutls",DEBUG, "m_ssl_gnutls.so: Failed to allocate certificate credentials: %s", gnutls_strerror(ret));
 311
 312                 if((ret =gnutls_certificate_set_x509_trust_file(x509_cred, cafile.c_str(), GNUTLS_X509_FMT_PEM)) < 0)
 313                         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));
 314
 315                 if((ret = gnutls_certificate_set_x509_crl_file (x509_cred, crlfile.c_str(), GNUTLS_X509_FMT_PEM)) < 0)
 316                         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));
 317
 318                 FileReader reader;
 319
 320                 reader.LoadFile(certfile);
 321                 std::string cert_string = reader.Contents();
 322                 gnutls_datum_t cert_datum = { (unsigned char*)cert_string.data(), cert_string.length() };
 323
 324                 reader.LoadFile(keyfile);
 325                 std::string key_string = reader.Contents();
 326                 gnutls_datum_t key_datum = { (unsigned char*)key_string.data(), key_string.length() };
 327
 328                 // If this fails, no SSL port will work. At all. So, do the smart thing - throw a ModuleException
 329                 unsigned int certcount = Conf->getInt("certcount", 3);
 330                 x509_certs.resize(certcount);
 331                 ret = gnutls_x509_crt_list_import(&x509_certs[0], &certcount, &cert_datum, GNUTLS_X509_FMT_PEM, GNUTLS_X509_CRT_LIST_IMPORT_FAIL_IF_EXCEED);
 332                 if (ret < 0)
 333                         throw ModuleException("Unable to load GnuTLS server certificate (" + certfile + "): " + std::string(gnutls_strerror(ret)));
 334                 x509_certs.resize(certcount);
 335
 336                 if((ret = gnutls_x509_privkey_import(x509_key, &key_datum, GNUTLS_X509_FMT_PEM)) < 0)
 337                         throw ModuleException("Unable to load GnuTLS server private key (" + keyfile + "): " + std::string(gnutls_strerror(ret)));
 338
 339                 if((ret = gnutls_certificate_set_x509_key(x509_cred, &x509_certs[0], certcount, x509_key)) < 0)
 340                         throw ModuleException("Unable to set GnuTLS cert/key pair: " + std::string(gnutls_strerror(ret)));
 341
 342                 // It's safe to call this every time as we cannot have this uninitialized, see constructor and below.
 343                 gnutls_priority_deinit(priority);
 344
 345                 // Try to set the priorities for ciphers, kex methods etc. to the user supplied string
 346                 // If the user did not supply anything then the string is already set to "NORMAL"
 347                 const char* priocstr = priorities.c_str();
 348                 const char* prioerror;
 349
 350                 if ((ret = gnutls_priority_init(&priority, priocstr, &prioerror)) < 0)
 351                 {
 352                         // gnutls did not understand the user supplied string, log and fall back to the default priorities
 353                         ServerInstance->Logs->Log("m_ssl_gnutls",DEFAULT, "m_ssl_gnutls.so: Failed to set priorities to \"%s\": %s Syntax error at position %d, falling back to default (NORMAL)", priorities.c_str(), gnutls_strerror(ret), (prioerror - priocstr));
 354                         gnutls_priority_init(&priority, "NORMAL", NULL);
 355                 }
 356
 357                 gnutls_certificate_client_set_retrieve_function (x509_cred, cert_callback);
 358
 359                 ret = gnutls_dh_params_init(&dh_params);
 360                 dh_alloc = (ret >= 0);
 361                 if (!dh_alloc)
 362                         ServerInstance->Logs->Log("m_ssl_gnutls",DEFAULT, "m_ssl_gnutls.so: Failed to initialise DH parameters: %s", gnutls_strerror(ret));
 363
 364                 // This may be on a large (once a day or week) timer eventually.
 365                 GenerateDHParams();
 366         }
 367
 368         void GenerateDHParams()
 369         {
 370                 // Generate Diffie Hellman parameters - for use with DHE
 371                 // kx algorithms. These should be discarded and regenerated
 372                 // once a day, once a week or once a month. Depending on the
 373                 // security requirements.
 374
 375                 if (!dh_alloc)
 376                         return;
 377
 378                 int ret;
 379
 380                 if((ret = gnutls_dh_params_generate2(dh_params, dh_bits)) < 0)
 381                         ServerInstance->Logs->Log("m_ssl_gnutls",DEFAULT, "m_ssl_gnutls.so: Failed to generate DH parameters (%d bits): %s", dh_bits, gnutls_strerror(ret));
 382         }
 383
 384         ~ModuleSSLGnuTLS()
 385         {
 386                 for(unsigned int i=0; i < x509_certs.size(); i++)
 387                         gnutls_x509_crt_deinit(x509_certs[i]);
 388
 389                 gnutls_x509_privkey_deinit(x509_key);
 390                 gnutls_priority_deinit(priority);
 391
 392                 if (dh_alloc)
 393                         gnutls_dh_params_deinit(dh_params);
 394                 if (cred_alloc)
 395                         gnutls_certificate_free_credentials(x509_cred);
 396
 397                 gnutls_global_deinit();
 398                 delete[] sessions;
 399                 ServerInstance->GenRandom = &ServerInstance->HandleGenRandom;
 400         }
 401
 402         void OnCleanup(int target_type, void* item)
 403         {
 404                 if(target_type == TYPE_USER)
 405                 {
 406                         LocalUser* user = IS_LOCAL(static_cast<User*>(item));
 407
 408                         if (user && user->eh.GetIOHook() == this)
 409                         {
 410                                 // User is using SSL, they're a local user, and they're using one of *our* SSL ports.
 411                                 // Potentially there could be multiple SSL modules loaded at once on different ports.
 412                                 ServerInstance->Users->QuitUser(user, "SSL module unloading");
 413                         }
 414                 }
 415         }
 416
 417         Version GetVersion()
 418         {
 419                 return Version("Provides SSL support for clients", VF_VENDOR);
 420         }
 421
 422
 423         void On005Numeric(std::string &output)
 424         {
 425                 if (!sslports.empty())
 426                         output.append(" SSL=" + sslports);
 427                 if (starttls.enabled)
 428                         output.append(" STARTTLS");
 429         }
 430
 431         void OnHookIO(StreamSocket* user, ListenSocket* lsb)
 432         {
 433                 if (!user->GetIOHook() && lsb->bind_tag->getString("ssl") == "gnutls")
 434                 {
 435                         /* Hook the user with our module */
 436                         user->AddIOHook(this);
 437                 }
 438         }
 439
 440         void OnRequest(Request& request)
 441         {
 442                 if (strcmp("GET_SSL_CERT", request.id) == 0)
 443                 {
 444                         SocketCertificateRequest& req = static_cast<SocketCertificateRequest&>(request);
 445                         int fd = req.sock->GetFd();
 446                         issl_session* session = &sessions[fd];
 447
 448                         req.cert = session->cert;
 449                 }
 450         }
 451
 452         void InitSession(StreamSocket* user, bool me_server)
 453         {
 454                 issl_session* session = &sessions[user->GetFd()];
 455
 456                 gnutls_init(&session->sess, me_server ? GNUTLS_SERVER : GNUTLS_CLIENT);
 457
 458                 gnutls_priority_set(session->sess, priority);
 459                 gnutls_credentials_set(session->sess, GNUTLS_CRD_CERTIFICATE, x509_cred);
 460                 gnutls_dh_set_prime_bits(session->sess, dh_bits);
 461                 gnutls_transport_set_ptr(session->sess, reinterpret_cast<gnutls_transport_ptr_t>(user));
 462                 gnutls_transport_set_push_function(session->sess, gnutls_push_wrapper);
 463                 gnutls_transport_set_pull_function(session->sess, gnutls_pull_wrapper);
 464
 465                 if (me_server)
 466                         gnutls_certificate_server_set_request(session->sess, GNUTLS_CERT_REQUEST); // Request client certificate if any.
 467
 468                 Handshake(session, user);
 469         }
 470
 471         void OnStreamSocketAccept(StreamSocket* user, irc::sockets::sockaddrs* client, irc::sockets::sockaddrs* server)
 472         {
 473                 issl_session* session = &sessions[user->GetFd()];
 474
 475                 /* For STARTTLS: Don't try and init a session on a socket that already has a session */
 476                 if (session->sess)
 477                         return;
 478
 479                 InitSession(user, true);
 480         }
 481
 482         void OnStreamSocketConnect(StreamSocket* user)
 483         {
 484                 InitSession(user, false);
 485         }
 486
 487         void OnStreamSocketClose(StreamSocket* user)
 488         {
 489                 CloseSession(&sessions[user->GetFd()]);
 490         }
 491
 492         int OnStreamSocketRead(StreamSocket* user, std::string& recvq)
 493         {
 494                 issl_session* session = &sessions[user->GetFd()];
 495
 496                 if (!session->sess)
 497                 {
 498                         CloseSession(session);
 499                         user->SetError("No SSL session");
 500                         return -1;
 501                 }
 502
 503                 if (session->status == ISSL_HANDSHAKING_READ || session->status == ISSL_HANDSHAKING_WRITE)
 504                 {
 505                         // The handshake isn't finished, try to finish it.
 506
 507                         if(!Handshake(session, user))
 508                         {
 509                                 if (session->status != ISSL_CLOSING)
 510                                         return 0;
 511                                 return -1;
 512                         }
 513                 }
 514
 515                 // If we resumed the handshake then session->status will be ISSL_HANDSHAKEN.
 516
 517                 if (session->status == ISSL_HANDSHAKEN)
 518                 {
 519                         char* buffer = ServerInstance->GetReadBuffer();
 520                         size_t bufsiz = ServerInstance->Config->NetBufferSize;
 521                         int ret = gnutls_record_recv(session->sess, buffer, bufsiz);
 522                         if (ret > 0)
 523                         {
 524                                 recvq.append(buffer, ret);
 525                                 return 1;
 526                         }
 527                         else if (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED)
 528                         {
 529                                 return 0;
 530                         }
 531                         else if (ret == 0)
 532                         {
 533                                 user->SetError("SSL Connection closed");
 534                                 CloseSession(session);
 535                                 return -1;
 536                         }
 537                         else
 538                         {
 539                                 user->SetError(gnutls_strerror(ret));
 540                                 CloseSession(session);
 541                                 return -1;
 542                         }
 543                 }
 544                 else if (session->status == ISSL_CLOSING)
 545                         return -1;
 546
 547                 return 0;
 548         }
 549
 550         int OnStreamSocketWrite(StreamSocket* user, std::string& sendq)
 551         {
 552                 issl_session* session = &sessions[user->GetFd()];
 553
 554                 if (!session->sess)
 555                 {
 556                         CloseSession(session);
 557                         user->SetError("No SSL session");
 558                         return -1;
 559                 }
 560
 561                 if (session->status == ISSL_HANDSHAKING_WRITE || session->status == ISSL_HANDSHAKING_READ)
 562                 {
 563                         // The handshake isn't finished, try to finish it.
 564                         Handshake(session, user);
 565                         if (session->status != ISSL_CLOSING)
 566                                 return 0;
 567                         return -1;
 568                 }
 569
 570                 int ret = 0;
 571
 572                 if (session->status == ISSL_HANDSHAKEN)
 573                 {
 574                         ret = gnutls_record_send(session->sess, sendq.data(), sendq.length());
 575
 576                         if (ret == (int)sendq.length())
 577                         {
 578                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_NO_WRITE);
 579                                 return 1;
 580                         }
 581                         else if (ret > 0)
 582                         {
 583                                 sendq = sendq.substr(ret);
 584                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_SINGLE_WRITE);
 585                                 return 0;
 586                         }
 587                         else if (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED || ret == 0)
 588                         {
 589                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_SINGLE_WRITE);
 590                                 return 0;
 591                         }
 592                         else // (ret < 0)
 593                         {
 594                                 user->SetError(gnutls_strerror(ret));
 595                                 CloseSession(session);
 596                                 return -1;
 597                         }
 598                 }
 599
 600                 return 0;
 601         }
 602
 603         bool Handshake(issl_session* session, StreamSocket* user)
 604         {
 605                 int ret = gnutls_handshake(session->sess);
 606
 607                 if (ret < 0)
 608                 {
 609                         if(ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED)
 610                         {
 611                                 // Handshake needs resuming later, read() or write() would have blocked.
 612
 613                                 if(gnutls_record_get_direction(session->sess) == 0)
 614                                 {
 615                                         // gnutls_handshake() wants to read() again.
 616                                         session->status = ISSL_HANDSHAKING_READ;
 617                                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_POLL_READ | FD_WANT_NO_WRITE);
 618                                 }
 619                                 else
 620                                 {
 621                                         // gnutls_handshake() wants to write() again.
 622                                         session->status = ISSL_HANDSHAKING_WRITE;
 623                                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_NO_READ | FD_WANT_SINGLE_WRITE);
 624                                 }
 625                         }
 626                         else
 627                         {
 628                                 user->SetError(std::string("Handshake Failed - ") + gnutls_strerror(ret));
 629                                 CloseSession(session);
 630                                 session->status = ISSL_CLOSING;
 631                         }
 632
 633                         return false;
 634                 }
 635                 else
 636                 {
 637                         // Change the seesion state
 638                         session->status = ISSL_HANDSHAKEN;
 639
 640                         VerifyCertificate(session,user);
 641
 642                         // Finish writing, if any left
 643                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_POLL_READ | FD_WANT_NO_WRITE | FD_ADD_TRIAL_WRITE);
 644
 645                         return true;
 646                 }
 647         }
 648
 649         void OnUserConnect(LocalUser* user)
 650         {
 651                 if (user->eh.GetIOHook() == this)
 652                 {
 653                         if (sessions[user->eh.GetFd()].sess)
 654                         {
 655                                 ssl_cert* cert = sessions[user->eh.GetFd()].cert;
 656                                 std::string cipher = gnutls_kx_get_name(gnutls_kx_get(sessions[user->eh.GetFd()].sess));
 657                                 cipher.append("-").append(gnutls_cipher_get_name(gnutls_cipher_get(sessions[user->eh.GetFd()].sess))).append("-");
 658                                 cipher.append(gnutls_mac_get_name(gnutls_mac_get(sessions[user->eh.GetFd()].sess)));
 659                                 if (cert->fingerprint.empty())
 660                                         user->WriteServ("NOTICE %s :*** You are connected using SSL cipher \"%s\"", user->nick.c_str(), cipher.c_str());
 661                                 else
 662                                         user->WriteServ("NOTICE %s :*** You are connected using SSL cipher \"%s\""
 663                                                 " and your SSL fingerprint is %s", user->nick.c_str(), cipher.c_str(), cert->fingerprint.c_str());
 664                         }
 665                 }
 666         }
 667
 668         void CloseSession(issl_session* session)
 669         {
 670                 if (session->sess)
 671                 {
 672                         gnutls_bye(session->sess, GNUTLS_SHUT_WR);
 673                         gnutls_deinit(session->sess);
 674                 }
 675                 session->sess = NULL;
 676                 session->cert = NULL;
 677                 session->status = ISSL_NONE;
 678         }
 679
 680         void VerifyCertificate(issl_session* session, StreamSocket* user)
 681         {
 682                 if (!session->sess || !user)
 683                         return;
 684
 685                 unsigned int status;
 686                 const gnutls_datum_t* cert_list;
 687                 int ret;
 688                 unsigned int cert_list_size;
 689                 gnutls_x509_crt_t cert;
 690                 char name[MAXBUF];
 691                 unsigned char digest[MAXBUF];
 692                 size_t digest_size = sizeof(digest);
 693                 size_t name_size = sizeof(name);
 694                 ssl_cert* certinfo = new ssl_cert;
 695                 session->cert = certinfo;
 696
 697                 /* This verification function uses the trusted CAs in the credentials
 698                  * structure. So you must have installed one or more CA certificates.
 699                  */
 700                 ret = gnutls_certificate_verify_peers2(session->sess, &status);
 701
 702                 if (ret < 0)
 703                 {
 704                         certinfo->error = std::string(gnutls_strerror(ret));
 705                         return;
 706                 }
 707
 708                 certinfo->invalid = (status & GNUTLS_CERT_INVALID);
 709                 certinfo->unknownsigner = (status & GNUTLS_CERT_SIGNER_NOT_FOUND);
 710                 certinfo->revoked = (status & GNUTLS_CERT_REVOKED);
 711                 certinfo->trusted = !(status & GNUTLS_CERT_SIGNER_NOT_CA);
 712
 713                 /* Up to here the process is the same for X.509 certificates and
 714                  * OpenPGP keys. From now on X.509 certificates are assumed. This can
 715                  * be easily extended to work with openpgp keys as well.
 716                  */
 717                 if (gnutls_certificate_type_get(session->sess) != GNUTLS_CRT_X509)
 718                 {
 719                         certinfo->error = "No X509 keys sent";
 720                         return;
 721                 }
 722
 723                 ret = gnutls_x509_crt_init(&cert);
 724                 if (ret < 0)
 725                 {
 726                         certinfo->error = gnutls_strerror(ret);
 727                         return;
 728                 }
 729
 730                 cert_list_size = 0;
 731                 cert_list = gnutls_certificate_get_peers(session->sess, &cert_list_size);
 732                 if (cert_list == NULL)
 733                 {
 734                         certinfo->error = "No certificate was found";
 735                         goto info_done_dealloc;
 736                 }
 737
 738                 /* This is not a real world example, since we only check the first
 739                  * certificate in the given chain.
 740                  */
 741
 742                 ret = gnutls_x509_crt_import(cert, &cert_list[0], GNUTLS_X509_FMT_DER);
 743                 if (ret < 0)
 744                 {
 745                         certinfo->error = gnutls_strerror(ret);
 746                         goto info_done_dealloc;
 747                 }
 748
 749                 gnutls_x509_crt_get_dn(cert, name, &name_size);
 750                 certinfo->dn = name;
 751
 752                 gnutls_x509_crt_get_issuer_dn(cert, name, &name_size);
 753                 certinfo->issuer = name;
 754
 755                 if ((ret = gnutls_x509_crt_get_fingerprint(cert, hash, digest, &digest_size)) < 0)
 756                 {
 757                         certinfo->error = gnutls_strerror(ret);
 758                 }
 759                 else
 760                 {
 761                         certinfo->fingerprint = irc::hex(digest, digest_size);
 762                 }
 763
 764                 /* Beware here we do not check for errors.
 765                  */
 766                 if ((gnutls_x509_crt_get_expiration_time(cert) < ServerInstance->Time()) || (gnutls_x509_crt_get_activation_time(cert) > ServerInstance->Time()))
 767                 {
 768                         certinfo->error = "Not activated, or expired certificate";
 769                 }
 770
 771 info_done_dealloc:
 772                 gnutls_x509_crt_deinit(cert);
 773         }
 774
 775         void OnEvent(Event& ev)
 776         {
 777                 if (starttls.enabled)
 778                         capHandler.HandleEvent(ev);
 779         }
 780 };
 781
 782 MODULE_INIT(ModuleSSLGnuTLS)