src/modules/extra/m_ssl_gnutls.cpp

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