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