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 "ssl.h"
  28 #include "m_cap.h"
  29
  30 #ifdef _WIN32
  31 # pragma comment(lib, "libgnutls-30.lib")
  32 #endif
  33
  34 /* $ModDesc: Provides SSL support for clients */
  35 /* $CompileFlags: pkgconfincludes("gnutls","/gnutls/gnutls.h","") iflt("pkg-config --modversion gnutls","2.12") exec("libgcrypt-config --cflags") */
  36 /* $LinkerFlags: rpath("pkg-config --libs gnutls") pkgconflibs("gnutls","/libgnutls.so","-lgnutls") iflt("pkg-config --modversion gnutls","2.12") exec("libgcrypt-config --libs") */
  37 /* $NoPedantic */
  38
  39 #ifndef GNUTLS_VERSION_MAJOR
  40 #define GNUTLS_VERSION_MAJOR LIBGNUTLS_VERSION_MAJOR
  41 #define GNUTLS_VERSION_MINOR LIBGNUTLS_VERSION_MINOR
  42 #define GNUTLS_VERSION_PATCH LIBGNUTLS_VERSION_PATCH
  43 #endif
  44
  45 // These don't exist in older GnuTLS versions
  46 #if ((GNUTLS_VERSION_MAJOR > 2) || (GNUTLS_VERSION_MAJOR == 2 && GNUTLS_VERSION_MINOR > 1) || (GNUTLS_VERSION_MAJOR == 2 && GNUTLS_VERSION_MINOR == 1 && GNUTLS_VERSION_PATCH >= 7))
  47 #define GNUTLS_NEW_PRIO_API
  48 #endif
  49
  50 #if(GNUTLS_VERSION_MAJOR < 2)
  51 typedef gnutls_certificate_credentials_t gnutls_certificate_credentials;
  52 typedef gnutls_dh_params_t gnutls_dh_params;
  53 #endif
  54
  55 #if (GNUTLS_VERSION_MAJOR > 2 || (GNUTLS_VERSION_MAJOR == 2 && GNUTLS_VERSION_MINOR >= 12))
  56 # define GNUTLS_HAS_RND
  57 # include <gnutls/crypto.h>
  58 #else
  59 # include <gcrypt.h>
  60 #endif
  61
  62 enum issl_status { ISSL_NONE, ISSL_HANDSHAKING_READ, ISSL_HANDSHAKING_WRITE, ISSL_HANDSHAKEN, ISSL_CLOSING, ISSL_CLOSED };
  63
  64 struct SSLConfig : public refcountbase
  65 {
  66         gnutls_certificate_credentials_t x509_cred;
  67         std::vector<gnutls_x509_crt_t> x509_certs;
  68         gnutls_x509_privkey_t x509_key;
  69         gnutls_dh_params_t dh_params;
  70 #ifdef GNUTLS_NEW_PRIO_API
  71         gnutls_priority_t priority;
  72 #endif
  73
  74         SSLConfig()
  75                 : x509_cred(NULL)
  76                 , x509_key(NULL)
  77                 , dh_params(NULL)
  78 #ifdef GNUTLS_NEW_PRIO_API
  79                 , priority(NULL)
  80 #endif
  81         {
  82         }
  83
  84         ~SSLConfig()
  85         {
  86                 ServerInstance->Logs->Log("m_ssl_gnutls", DEBUG, "Destroying SSLConfig %p", (void*)this);
  87
  88                 if (x509_cred)
  89                         gnutls_certificate_free_credentials(x509_cred);
  90
  91                 for (unsigned int i = 0; i < x509_certs.size(); i++)
  92                         gnutls_x509_crt_deinit(x509_certs[i]);
  93
  94                 if (x509_key)
  95                         gnutls_x509_privkey_deinit(x509_key);
  96
  97                 if (dh_params)
  98                         gnutls_dh_params_deinit(dh_params);
  99
 100 #ifdef GNUTLS_NEW_PRIO_API
 101                 if (priority)
 102                         gnutls_priority_deinit(priority);
 103 #endif
 104         }
 105 };
 106
 107 static reference<SSLConfig> currconf;
 108
 109 static SSLConfig* GetSessionConfig(gnutls_session_t session);
 110
 111 #if(GNUTLS_VERSION_MAJOR < 2 || ( GNUTLS_VERSION_MAJOR == 2 && GNUTLS_VERSION_MINOR < 12 ) )
 112 static int cert_callback (gnutls_session_t session, const gnutls_datum_t * req_ca_rdn, int nreqs,
 113         const gnutls_pk_algorithm_t * sign_algos, int sign_algos_length, gnutls_retr_st * st) {
 114
 115         st->type = GNUTLS_CRT_X509;
 116 #else
 117 static int cert_callback (gnutls_session_t session, const gnutls_datum_t * req_ca_rdn, int nreqs,
 118         const gnutls_pk_algorithm_t * sign_algos, int sign_algos_length, gnutls_retr2_st * st) {
 119         st->cert_type = GNUTLS_CRT_X509;
 120         st->key_type = GNUTLS_PRIVKEY_X509;
 121 #endif
 122         SSLConfig* conf = GetSessionConfig(session);
 123         std::vector<gnutls_x509_crt_t>& x509_certs = conf->x509_certs;
 124         st->ncerts = x509_certs.size();
 125         st->cert.x509 = &x509_certs[0];
 126         st->key.x509 = conf->x509_key;
 127         st->deinit_all = 0;
 128
 129         return 0;
 130 }
 131
 132 class RandGen : public HandlerBase2<void, char*, size_t>
 133 {
 134  public:
 135         RandGen() {}
 136         void Call(char* buffer, size_t len)
 137         {
 138 #ifdef GNUTLS_HAS_RND
 139                 gnutls_rnd(GNUTLS_RND_RANDOM, buffer, len);
 140 #else
 141                 gcry_randomize(buffer, len, GCRY_STRONG_RANDOM);
 142 #endif
 143         }
 144 };
 145
 146 /** Represents an SSL user's extra data
 147  */
 148 class issl_session
 149 {
 150 public:
 151         StreamSocket* socket;
 152         gnutls_session_t sess;
 153         issl_status status;
 154         reference<ssl_cert> cert;
 155         reference<SSLConfig> config;
 156
 157         issl_session() : socket(NULL), sess(NULL), status(ISSL_NONE) {}
 158 };
 159
 160 static SSLConfig* GetSessionConfig(gnutls_session_t sess)
 161 {
 162         issl_session* session = reinterpret_cast<issl_session*>(gnutls_transport_get_ptr(sess));
 163         return session->config;
 164 }
 165
 166 class CommandStartTLS : public SplitCommand
 167 {
 168  public:
 169         bool enabled;
 170         CommandStartTLS (Module* mod) : SplitCommand(mod, "STARTTLS")
 171         {
 172                 enabled = true;
 173                 works_before_reg = true;
 174         }
 175
 176         CmdResult HandleLocal(const std::vector<std::string> &parameters, LocalUser *user)
 177         {
 178                 if (!enabled)
 179                 {
 180                         user->WriteNumeric(691, "%s :STARTTLS is not enabled", user->nick.c_str());
 181                         return CMD_FAILURE;
 182                 }
 183
 184                 if (user->registered == REG_ALL)
 185                 {
 186                         user->WriteNumeric(691, "%s :STARTTLS is not permitted after client registration is complete", user->nick.c_str());
 187                 }
 188                 else
 189                 {
 190                         if (!user->eh.GetIOHook())
 191                         {
 192                                 user->WriteNumeric(670, "%s :STARTTLS successful, go ahead with TLS handshake", user->nick.c_str());
 193                                 /* We need to flush the write buffer prior to adding the IOHook,
 194                                  * otherwise we'll be sending this line inside the SSL session - which
 195                                  * won't start its handshake until the client gets this line. Currently,
 196                                  * we assume the write will not block here; this is usually safe, as
 197                                  * STARTTLS is sent very early on in the registration phase, where the
 198                                  * user hasn't built up much sendq. Handling a blocked write here would
 199                                  * be very annoying.
 200                                  */
 201                                 user->eh.DoWrite();
 202                                 user->eh.AddIOHook(creator);
 203                                 creator->OnStreamSocketAccept(&user->eh, NULL, NULL);
 204                         }
 205                         else
 206                                 user->WriteNumeric(691, "%s :STARTTLS failure", user->nick.c_str());
 207                 }
 208
 209                 return CMD_FAILURE;
 210         }
 211 };
 212
 213 class ModuleSSLGnuTLS : public Module
 214 {
 215         issl_session* sessions;
 216
 217         gnutls_digest_algorithm_t hash;
 218
 219         std::string sslports;
 220         int dh_bits;
 221
 222         RandGen randhandler;
 223         CommandStartTLS starttls;
 224
 225         GenericCap capHandler;
 226         ServiceProvider iohook;
 227
 228         inline static const char* UnknownIfNULL(const char* str)
 229         {
 230                 return str ? str : "UNKNOWN";
 231         }
 232
 233         static ssize_t gnutls_pull_wrapper(gnutls_transport_ptr_t session_wrap, void* buffer, size_t size)
 234         {
 235                 issl_session* session = reinterpret_cast<issl_session*>(session_wrap);
 236                 if (session->socket->GetEventMask() & FD_READ_WILL_BLOCK)
 237                 {
 238 #ifdef _WIN32
 239                         gnutls_transport_set_errno(session->sess, EAGAIN);
 240 #else
 241                         errno = EAGAIN;
 242 #endif
 243                         return -1;
 244                 }
 245
 246                 int rv = ServerInstance->SE->Recv(session->socket, reinterpret_cast<char *>(buffer), size, 0);
 247
 248 #ifdef _WIN32
 249                 if (rv < 0)
 250                 {
 251                         /* Windows doesn't use errno, but gnutls does, so check SocketEngine::IgnoreError()
 252                          * and then set errno appropriately.
 253                          * The gnutls library may also have a different errno variable than us, see
 254                          * gnutls_transport_set_errno(3).
 255                          */
 256                         gnutls_transport_set_errno(session->sess, SocketEngine::IgnoreError() ? EAGAIN : errno);
 257                 }
 258 #endif
 259
 260                 if (rv < (int)size)
 261                         ServerInstance->SE->ChangeEventMask(session->socket, FD_READ_WILL_BLOCK);
 262                 return rv;
 263         }
 264
 265         static ssize_t gnutls_push_wrapper(gnutls_transport_ptr_t session_wrap, const void* buffer, size_t size)
 266         {
 267                 issl_session* session = reinterpret_cast<issl_session*>(session_wrap);
 268                 if (session->socket->GetEventMask() & FD_WRITE_WILL_BLOCK)
 269                 {
 270 #ifdef _WIN32
 271                         gnutls_transport_set_errno(session->sess, EAGAIN);
 272 #else
 273                         errno = EAGAIN;
 274 #endif
 275                         return -1;
 276                 }
 277
 278                 int rv = ServerInstance->SE->Send(session->socket, reinterpret_cast<const char *>(buffer), size, 0);
 279
 280 #ifdef _WIN32
 281                 if (rv < 0)
 282                 {
 283                         /* Windows doesn't use errno, but gnutls does, so check SocketEngine::IgnoreError()
 284                          * and then set errno appropriately.
 285                          * The gnutls library may also have a different errno variable than us, see
 286                          * gnutls_transport_set_errno(3).
 287                          */
 288                         gnutls_transport_set_errno(session->sess, SocketEngine::IgnoreError() ? EAGAIN : errno);
 289                 }
 290 #endif
 291
 292                 if (rv < (int)size)
 293                         ServerInstance->SE->ChangeEventMask(session->socket, FD_WRITE_WILL_BLOCK);
 294                 return rv;
 295         }
 296
 297  public:
 298
 299         ModuleSSLGnuTLS()
 300                 : starttls(this), capHandler(this, "tls"), iohook(this, "ssl/gnutls", SERVICE_IOHOOK)
 301         {
 302 #ifndef GNUTLS_HAS_RND
 303                 gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
 304 #endif
 305
 306                 sessions = new issl_session[ServerInstance->SE->GetMaxFds()];
 307
 308                 gnutls_global_init(); // This must be called once in the program
 309         }
 310
 311         void init()
 312         {
 313                 currconf = new SSLConfig;
 314                 InitSSLConfig(currconf);
 315
 316                 ServerInstance->GenRandom = &randhandler;
 317
 318                 Implementation eventlist[] = { I_On005Numeric, I_OnRehash, I_OnModuleRehash, I_OnUserConnect,
 319                         I_OnEvent, I_OnHookIO, I_OnCheckReady };
 320                 ServerInstance->Modules->Attach(eventlist, this, sizeof(eventlist)/sizeof(Implementation));
 321
 322                 ServerInstance->Modules->AddService(iohook);
 323                 ServerInstance->Modules->AddService(starttls);
 324         }
 325
 326         void OnRehash(User* user)
 327         {
 328                 sslports.clear();
 329
 330                 ConfigTag* Conf = ServerInstance->Config->ConfValue("gnutls");
 331                 starttls.enabled = Conf->getBool("starttls", true);
 332
 333                 if (Conf->getBool("showports", true))
 334                 {
 335                         sslports = Conf->getString("advertisedports");
 336                         if (!sslports.empty())
 337                                 return;
 338
 339                         for (size_t i = 0; i < ServerInstance->ports.size(); i++)
 340                         {
 341                                 ListenSocket* port = ServerInstance->ports[i];
 342                                 if (port->bind_tag->getString("ssl") != "gnutls")
 343                                         continue;
 344
 345                                 const std::string& portid = port->bind_desc;
 346                                 ServerInstance->Logs->Log("m_ssl_gnutls", DEFAULT, "m_ssl_gnutls.so: Enabling SSL for port %s", portid.c_str());
 347
 348                                 if (port->bind_tag->getString("type", "clients") == "clients" && port->bind_addr != "127.0.0.1")
 349                                 {
 350                                         /*
 351                                          * Found an SSL port for clients that is not bound to 127.0.0.1 and handled by us, display
 352                                          * the IP:port in ISUPPORT.
 353                                          *
 354                                          * We used to advertise all ports seperated by a ';' char that matched the above criteria,
 355                                          * but this resulted in too long ISUPPORT lines if there were lots of ports to be displayed.
 356                                          * To solve this by default we now only display the first IP:port found and let the user
 357                                          * configure the exact value for the 005 token, if necessary.
 358                                          */
 359                                         sslports = portid;
 360                                         break;
 361                                 }
 362                         }
 363                 }
 364         }
 365
 366         void OnModuleRehash(User* user, const std::string &param)
 367         {
 368                 if(param != "ssl")
 369                         return;
 370
 371                 reference<SSLConfig> newconf = new SSLConfig;
 372                 try
 373                 {
 374                         InitSSLConfig(newconf);
 375                 }
 376                 catch (ModuleException& ex)
 377                 {
 378                         ServerInstance->Logs->Log("m_ssl_gnutls", DEFAULT, "m_ssl_gnutls: Not applying new config. %s", ex.GetReason());
 379                         return;
 380                 }
 381
 382                 ServerInstance->Logs->Log("m_ssl_gnutls", DEFAULT, "m_ssl_gnutls: Applying new config, old config is in use by %d connection(s)", currconf->GetReferenceCount()-1);
 383                 currconf = newconf;
 384         }
 385
 386         void InitSSLConfig(SSLConfig* config)
 387         {
 388                 ServerInstance->Logs->Log("m_ssl_gnutls", DEBUG, "Initializing new SSLConfig %p", (void*)config);
 389
 390                 std::string keyfile;
 391                 std::string certfile;
 392                 std::string cafile;
 393                 std::string crlfile;
 394                 OnRehash(NULL);
 395
 396                 ConfigTag* Conf = ServerInstance->Config->ConfValue("gnutls");
 397
 398                 cafile = Conf->getString("cafile", CONFIG_PATH "/ca.pem");
 399                 crlfile = Conf->getString("crlfile", CONFIG_PATH "/crl.pem");
 400                 certfile = Conf->getString("certfile", CONFIG_PATH "/cert.pem");
 401                 keyfile = Conf->getString("keyfile", CONFIG_PATH "/key.pem");
 402                 dh_bits = Conf->getInt("dhbits");
 403                 std::string hashname = Conf->getString("hash", "md5");
 404
 405                 // The GnuTLS manual states that the gnutls_set_default_priority()
 406                 // call we used previously when initializing the session is the same
 407                 // as setting the "NORMAL" priority string.
 408                 // Thus if the setting below is not in the config we will behave exactly
 409                 // the same as before, when the priority setting wasn't available.
 410                 std::string priorities = Conf->getString("priority", "NORMAL");
 411
 412                 if((dh_bits != 768) && (dh_bits != 1024) && (dh_bits != 2048) && (dh_bits != 3072) && (dh_bits != 4096))
 413                         dh_bits = 1024;
 414
 415                 if (hashname == "md5")
 416                         hash = GNUTLS_DIG_MD5;
 417                 else if (hashname == "sha1")
 418                         hash = GNUTLS_DIG_SHA1;
 419 #ifdef INSPIRCD_GNUTLS_ENABLE_SHA256_FINGERPRINT
 420                 else if (hashname == "sha256")
 421                         hash = GNUTLS_DIG_SHA256;
 422 #endif
 423                 else
 424                         throw ModuleException("Unknown hash type " + hashname);
 425
 426
 427                 int ret;
 428
 429                 gnutls_certificate_credentials_t& x509_cred = config->x509_cred;
 430
 431                 ret = gnutls_certificate_allocate_credentials(&x509_cred);
 432                 if (ret < 0)
 433                 {
 434                         // Set to NULL because we can't be sure what value is in it and we must not try to
 435                         // deallocate it in case of an error
 436                         x509_cred = NULL;
 437                         throw ModuleException("Failed to allocate certificate credentials: " + std::string(gnutls_strerror(ret)));
 438                 }
 439
 440                 if((ret =gnutls_certificate_set_x509_trust_file(x509_cred, cafile.c_str(), GNUTLS_X509_FMT_PEM)) < 0)
 441                         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));
 442
 443                 if((ret = gnutls_certificate_set_x509_crl_file (x509_cred, crlfile.c_str(), GNUTLS_X509_FMT_PEM)) < 0)
 444                         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));
 445
 446                 FileReader reader;
 447
 448                 reader.LoadFile(certfile);
 449                 std::string cert_string = reader.Contents();
 450                 gnutls_datum_t cert_datum = { (unsigned char*)cert_string.data(), static_cast<unsigned int>(cert_string.length()) };
 451
 452                 reader.LoadFile(keyfile);
 453                 std::string key_string = reader.Contents();
 454                 gnutls_datum_t key_datum = { (unsigned char*)key_string.data(), static_cast<unsigned int>(key_string.length()) };
 455
 456                 std::vector<gnutls_x509_crt_t>& x509_certs = config->x509_certs;
 457
 458                 // If this fails, no SSL port will work. At all. So, do the smart thing - throw a ModuleException
 459                 unsigned int certcount = 3;
 460                 x509_certs.resize(certcount);
 461                 ret = gnutls_x509_crt_list_import(&x509_certs[0], &certcount, &cert_datum, GNUTLS_X509_FMT_PEM, GNUTLS_X509_CRT_LIST_IMPORT_FAIL_IF_EXCEED);
 462                 if (ret == GNUTLS_E_SHORT_MEMORY_BUFFER)
 463                 {
 464                         // 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
 465                         x509_certs.resize(certcount);
 466                         ret = gnutls_x509_crt_list_import(&x509_certs[0], &certcount, &cert_datum, GNUTLS_X509_FMT_PEM, GNUTLS_X509_CRT_LIST_IMPORT_FAIL_IF_EXCEED);
 467                 }
 468
 469                 if (ret <= 0)
 470                 {
 471                         // clear the vector so we won't call gnutls_x509_crt_deinit() on the (uninited) certs later
 472                         x509_certs.clear();
 473                         throw ModuleException("Unable to load GnuTLS server certificate (" + certfile + "): " + ((ret < 0) ? (std::string(gnutls_strerror(ret))) : "No certs could be read"));
 474                 }
 475                 x509_certs.resize(ret);
 476
 477                 gnutls_x509_privkey_t& x509_key = config->x509_key;
 478                 if (gnutls_x509_privkey_init(&x509_key) < 0)
 479                 {
 480                         // Make sure the destructor does not try to deallocate this, see above
 481                         x509_key = NULL;
 482                         throw ModuleException("Unable to initialize private key");
 483                 }
 484
 485                 if((ret = gnutls_x509_privkey_import(x509_key, &key_datum, GNUTLS_X509_FMT_PEM)) < 0)
 486                         throw ModuleException("Unable to load GnuTLS server private key (" + keyfile + "): " + std::string(gnutls_strerror(ret)));
 487
 488                 if((ret = gnutls_certificate_set_x509_key(x509_cred, &x509_certs[0], certcount, x509_key)) < 0)
 489                         throw ModuleException("Unable to set GnuTLS cert/key pair: " + std::string(gnutls_strerror(ret)));
 490
 491                 #ifdef GNUTLS_NEW_PRIO_API
 492                 // Try to set the priorities for ciphers, kex methods etc. to the user supplied string
 493                 // If the user did not supply anything then the string is already set to "NORMAL"
 494                 const char* priocstr = priorities.c_str();
 495                 const char* prioerror;
 496
 497                 gnutls_priority_t& priority = config->priority;
 498                 if ((ret = gnutls_priority_init(&priority, priocstr, &prioerror)) < 0)
 499                 {
 500                         // gnutls did not understand the user supplied string, log and fall back to the default priorities
 501                         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));
 502                         gnutls_priority_init(&priority, "NORMAL", NULL);
 503                 }
 504
 505                 #else
 506                 if (priorities != "NORMAL")
 507                         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.");
 508                 #endif
 509
 510                 #if(GNUTLS_VERSION_MAJOR < 2 || ( GNUTLS_VERSION_MAJOR == 2 && GNUTLS_VERSION_MINOR < 12 ) )
 511                 gnutls_certificate_client_set_retrieve_function (x509_cred, cert_callback);
 512                 #else
 513                 gnutls_certificate_set_retrieve_function (x509_cred, cert_callback);
 514                 #endif
 515
 516                 gnutls_dh_params_t& dh_params = config->dh_params;
 517                 ret = gnutls_dh_params_init(&dh_params);
 518                 if (ret < 0)
 519                 {
 520                         // Make sure the destructor does not try to deallocate this, see above
 521                         dh_params = NULL;
 522                         ServerInstance->Logs->Log("m_ssl_gnutls",DEFAULT, "m_ssl_gnutls.so: Failed to initialise DH parameters: %s", gnutls_strerror(ret));
 523                         return;
 524                 }
 525
 526                 std::string dhfile = Conf->getString("dhfile");
 527                 if (!dhfile.empty())
 528                 {
 529                         // Try to load DH params from file
 530                         reader.LoadFile(dhfile);
 531                         std::string dhstring = reader.Contents();
 532                         gnutls_datum_t dh_datum = { (unsigned char*)dhstring.data(), static_cast<unsigned int>(dhstring.length()) };
 533
 534                         if ((ret = gnutls_dh_params_import_pkcs3(dh_params, &dh_datum, GNUTLS_X509_FMT_PEM)) < 0)
 535                         {
 536                                 // File unreadable or GnuTLS was unhappy with the contents, generate the DH primes now
 537                                 ServerInstance->Logs->Log("m_ssl_gnutls", DEFAULT, "m_ssl_gnutls.so: Generating DH parameters because I failed to load them from file '%s': %s", dhfile.c_str(), gnutls_strerror(ret));
 538                                 GenerateDHParams(dh_params);
 539                         }
 540                 }
 541                 else
 542                 {
 543                         GenerateDHParams(dh_params);
 544                 }
 545
 546                 gnutls_certificate_set_dh_params(x509_cred, dh_params);
 547         }
 548
 549         void GenerateDHParams(gnutls_dh_params_t dh_params)
 550         {
 551                 // Generate Diffie Hellman parameters - for use with DHE
 552                 // kx algorithms. These should be discarded and regenerated
 553                 // once a day, once a week or once a month. Depending on the
 554                 // security requirements.
 555
 556                 int ret;
 557
 558                 if((ret = gnutls_dh_params_generate2(dh_params, dh_bits)) < 0)
 559                         ServerInstance->Logs->Log("m_ssl_gnutls",DEFAULT, "m_ssl_gnutls.so: Failed to generate DH parameters (%d bits): %s", dh_bits, gnutls_strerror(ret));
 560         }
 561
 562         ~ModuleSSLGnuTLS()
 563         {
 564                 currconf = NULL;
 565
 566                 gnutls_global_deinit();
 567                 delete[] sessions;
 568                 ServerInstance->GenRandom = &ServerInstance->HandleGenRandom;
 569         }
 570
 571         void OnCleanup(int target_type, void* item)
 572         {
 573                 if(target_type == TYPE_USER)
 574                 {
 575                         LocalUser* user = IS_LOCAL(static_cast<User*>(item));
 576
 577                         if (user && user->eh.GetIOHook() == this)
 578                         {
 579                                 // User is using SSL, they're a local user, and they're using one of *our* SSL ports.
 580                                 // Potentially there could be multiple SSL modules loaded at once on different ports.
 581                                 ServerInstance->Users->QuitUser(user, "SSL module unloading");
 582                         }
 583                 }
 584         }
 585
 586         Version GetVersion()
 587         {
 588                 return Version("Provides SSL support for clients", VF_VENDOR);
 589         }
 590
 591
 592         void On005Numeric(std::string &output)
 593         {
 594                 if (!sslports.empty())
 595                         output.append(" SSL=" + sslports);
 596                 if (starttls.enabled)
 597                         output.append(" STARTTLS");
 598         }
 599
 600         void OnHookIO(StreamSocket* user, ListenSocket* lsb)
 601         {
 602                 if (!user->GetIOHook() && lsb->bind_tag->getString("ssl") == "gnutls")
 603                 {
 604                         /* Hook the user with our module */
 605                         user->AddIOHook(this);
 606                 }
 607         }
 608
 609         void OnRequest(Request& request)
 610         {
 611                 if (strcmp("GET_SSL_CERT", request.id) == 0)
 612                 {
 613                         SocketCertificateRequest& req = static_cast<SocketCertificateRequest&>(request);
 614                         int fd = req.sock->GetFd();
 615                         issl_session* session = &sessions[fd];
 616
 617                         req.cert = session->cert;
 618                 }
 619                 else if (!strcmp("GET_RAW_SSL_SESSION", request.id))
 620                 {
 621                         SSLRawSessionRequest& req = static_cast<SSLRawSessionRequest&>(request);
 622                         if ((req.fd >= 0) && (req.fd < ServerInstance->SE->GetMaxFds()))
 623                                 req.data = reinterpret_cast<void*>(sessions[req.fd].sess);
 624                 }
 625         }
 626
 627         void InitSession(StreamSocket* user, bool me_server)
 628         {
 629                 issl_session* session = &sessions[user->GetFd()];
 630
 631                 gnutls_init(&session->sess, me_server ? GNUTLS_SERVER : GNUTLS_CLIENT);
 632                 session->socket = user;
 633                 session->config = currconf;
 634
 635                 #ifdef GNUTLS_NEW_PRIO_API
 636                 gnutls_priority_set(session->sess, currconf->priority);
 637                 #else
 638                 gnutls_set_default_priority(session->sess);
 639                 #endif
 640                 gnutls_credentials_set(session->sess, GNUTLS_CRD_CERTIFICATE, currconf->x509_cred);
 641                 gnutls_dh_set_prime_bits(session->sess, dh_bits);
 642                 gnutls_transport_set_ptr(session->sess, reinterpret_cast<gnutls_transport_ptr_t>(session));
 643                 gnutls_transport_set_push_function(session->sess, gnutls_push_wrapper);
 644                 gnutls_transport_set_pull_function(session->sess, gnutls_pull_wrapper);
 645
 646                 if (me_server)
 647                         gnutls_certificate_server_set_request(session->sess, GNUTLS_CERT_REQUEST); // Request client certificate if any.
 648
 649                 Handshake(session, user);
 650         }
 651
 652         void OnStreamSocketAccept(StreamSocket* user, irc::sockets::sockaddrs* client, irc::sockets::sockaddrs* server)
 653         {
 654                 issl_session* session = &sessions[user->GetFd()];
 655
 656                 /* For STARTTLS: Don't try and init a session on a socket that already has a session */
 657                 if (session->sess)
 658                         return;
 659
 660                 InitSession(user, true);
 661         }
 662
 663         void OnStreamSocketConnect(StreamSocket* user)
 664         {
 665                 InitSession(user, false);
 666         }
 667
 668         void OnStreamSocketClose(StreamSocket* user)
 669         {
 670                 CloseSession(&sessions[user->GetFd()]);
 671         }
 672
 673         int OnStreamSocketRead(StreamSocket* user, std::string& recvq)
 674         {
 675                 issl_session* session = &sessions[user->GetFd()];
 676
 677                 if (!session->sess)
 678                 {
 679                         CloseSession(session);
 680                         user->SetError("No SSL session");
 681                         return -1;
 682                 }
 683
 684                 if (session->status == ISSL_HANDSHAKING_READ || session->status == ISSL_HANDSHAKING_WRITE)
 685                 {
 686                         // The handshake isn't finished, try to finish it.
 687
 688                         if(!Handshake(session, user))
 689                         {
 690                                 if (session->status != ISSL_CLOSING)
 691                                         return 0;
 692                                 return -1;
 693                         }
 694                 }
 695
 696                 // If we resumed the handshake then session->status will be ISSL_HANDSHAKEN.
 697
 698                 if (session->status == ISSL_HANDSHAKEN)
 699                 {
 700                         char* buffer = ServerInstance->GetReadBuffer();
 701                         size_t bufsiz = ServerInstance->Config->NetBufferSize;
 702                         int ret = gnutls_record_recv(session->sess, buffer, bufsiz);
 703                         if (ret > 0)
 704                         {
 705                                 recvq.append(buffer, ret);
 706                                 return 1;
 707                         }
 708                         else if (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED)
 709                         {
 710                                 return 0;
 711                         }
 712                         else if (ret == 0)
 713                         {
 714                                 user->SetError("Connection closed");
 715                                 CloseSession(session);
 716                                 return -1;
 717                         }
 718                         else
 719                         {
 720                                 user->SetError(gnutls_strerror(ret));
 721                                 CloseSession(session);
 722                                 return -1;
 723                         }
 724                 }
 725                 else if (session->status == ISSL_CLOSING)
 726                         return -1;
 727
 728                 return 0;
 729         }
 730
 731         int OnStreamSocketWrite(StreamSocket* user, std::string& sendq)
 732         {
 733                 issl_session* session = &sessions[user->GetFd()];
 734
 735                 if (!session->sess)
 736                 {
 737                         CloseSession(session);
 738                         user->SetError("No SSL session");
 739                         return -1;
 740                 }
 741
 742                 if (session->status == ISSL_HANDSHAKING_WRITE || session->status == ISSL_HANDSHAKING_READ)
 743                 {
 744                         // The handshake isn't finished, try to finish it.
 745                         Handshake(session, user);
 746                         if (session->status != ISSL_CLOSING)
 747                                 return 0;
 748                         return -1;
 749                 }
 750
 751                 int ret = 0;
 752
 753                 if (session->status == ISSL_HANDSHAKEN)
 754                 {
 755                         ret = gnutls_record_send(session->sess, sendq.data(), sendq.length());
 756
 757                         if (ret == (int)sendq.length())
 758                         {
 759                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_NO_WRITE);
 760                                 return 1;
 761                         }
 762                         else if (ret > 0)
 763                         {
 764                                 sendq = sendq.substr(ret);
 765                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_SINGLE_WRITE);
 766                                 return 0;
 767                         }
 768                         else if (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED || ret == 0)
 769                         {
 770                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_SINGLE_WRITE);
 771                                 return 0;
 772                         }
 773                         else // (ret < 0)
 774                         {
 775                                 user->SetError(gnutls_strerror(ret));
 776                                 CloseSession(session);
 777                                 return -1;
 778                         }
 779                 }
 780
 781                 return 0;
 782         }
 783
 784         bool Handshake(issl_session* session, StreamSocket* user)
 785         {
 786                 int ret = gnutls_handshake(session->sess);
 787
 788                 if (ret < 0)
 789                 {
 790                         if(ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED)
 791                         {
 792                                 // Handshake needs resuming later, read() or write() would have blocked.
 793
 794                                 if(gnutls_record_get_direction(session->sess) == 0)
 795                                 {
 796                                         // gnutls_handshake() wants to read() again.
 797                                         session->status = ISSL_HANDSHAKING_READ;
 798                                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_POLL_READ | FD_WANT_NO_WRITE);
 799                                 }
 800                                 else
 801                                 {
 802                                         // gnutls_handshake() wants to write() again.
 803                                         session->status = ISSL_HANDSHAKING_WRITE;
 804                                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_NO_READ | FD_WANT_SINGLE_WRITE);
 805                                 }
 806                         }
 807                         else
 808                         {
 809                                 user->SetError("Handshake Failed - " + std::string(gnutls_strerror(ret)));
 810                                 CloseSession(session);
 811                                 session->status = ISSL_CLOSING;
 812                         }
 813
 814                         return false;
 815                 }
 816                 else
 817                 {
 818                         // Change the seesion state
 819                         session->status = ISSL_HANDSHAKEN;
 820
 821                         VerifyCertificate(session,user);
 822
 823                         // Finish writing, if any left
 824                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_POLL_READ | FD_WANT_NO_WRITE | FD_ADD_TRIAL_WRITE);
 825
 826                         return true;
 827                 }
 828         }
 829
 830         void OnUserConnect(LocalUser* user)
 831         {
 832                 if (user->eh.GetIOHook() == this)
 833                 {
 834                         if (sessions[user->eh.GetFd()].sess)
 835                         {
 836                                 const gnutls_session_t& sess = sessions[user->eh.GetFd()].sess;
 837                                 std::string cipher = UnknownIfNULL(gnutls_kx_get_name(gnutls_kx_get(sess)));
 838                                 cipher.append("-").append(UnknownIfNULL(gnutls_cipher_get_name(gnutls_cipher_get(sess)))).append("-");
 839                                 cipher.append(UnknownIfNULL(gnutls_mac_get_name(gnutls_mac_get(sess))));
 840
 841                                 ssl_cert* cert = sessions[user->eh.GetFd()].cert;
 842                                 if (cert->fingerprint.empty())
 843                                         user->WriteServ("NOTICE %s :*** You are connected using SSL cipher \"%s\"", user->nick.c_str(), cipher.c_str());
 844                                 else
 845                                         user->WriteServ("NOTICE %s :*** You are connected using SSL cipher \"%s\""
 846                                                 " and your SSL fingerprint is %s", user->nick.c_str(), cipher.c_str(), cert->fingerprint.c_str());
 847                         }
 848                 }
 849         }
 850
 851         void CloseSession(issl_session* session)
 852         {
 853                 if (session->sess)
 854                 {
 855                         gnutls_bye(session->sess, GNUTLS_SHUT_WR);
 856                         gnutls_deinit(session->sess);
 857                 }
 858                 session->socket = NULL;
 859                 session->sess = NULL;
 860                 session->cert = NULL;
 861                 session->status = ISSL_NONE;
 862                 session->config = NULL;
 863         }
 864
 865         void VerifyCertificate(issl_session* session, StreamSocket* user)
 866         {
 867                 if (!session->sess || !user)
 868                         return;
 869
 870                 unsigned int status;
 871                 const gnutls_datum_t* cert_list;
 872                 int ret;
 873                 unsigned int cert_list_size;
 874                 gnutls_x509_crt_t cert;
 875                 char name[MAXBUF];
 876                 unsigned char digest[MAXBUF];
 877                 size_t digest_size = sizeof(digest);
 878                 size_t name_size = sizeof(name);
 879                 ssl_cert* certinfo = new ssl_cert;
 880                 session->cert = certinfo;
 881
 882                 /* This verification function uses the trusted CAs in the credentials
 883                  * structure. So you must have installed one or more CA certificates.
 884                  */
 885                 ret = gnutls_certificate_verify_peers2(session->sess, &status);
 886
 887                 if (ret < 0)
 888                 {
 889                         certinfo->error = std::string(gnutls_strerror(ret));
 890                         return;
 891                 }
 892
 893                 certinfo->invalid = (status & GNUTLS_CERT_INVALID);
 894                 certinfo->unknownsigner = (status & GNUTLS_CERT_SIGNER_NOT_FOUND);
 895                 certinfo->revoked = (status & GNUTLS_CERT_REVOKED);
 896                 certinfo->trusted = !(status & GNUTLS_CERT_SIGNER_NOT_CA);
 897
 898                 /* Up to here the process is the same for X.509 certificates and
 899                  * OpenPGP keys. From now on X.509 certificates are assumed. This can
 900                  * be easily extended to work with openpgp keys as well.
 901                  */
 902                 if (gnutls_certificate_type_get(session->sess) != GNUTLS_CRT_X509)
 903                 {
 904                         certinfo->error = "No X509 keys sent";
 905                         return;
 906                 }
 907
 908                 ret = gnutls_x509_crt_init(&cert);
 909                 if (ret < 0)
 910                 {
 911                         certinfo->error = gnutls_strerror(ret);
 912                         return;
 913                 }
 914
 915                 cert_list_size = 0;
 916                 cert_list = gnutls_certificate_get_peers(session->sess, &cert_list_size);
 917                 if (cert_list == NULL)
 918                 {
 919                         certinfo->error = "No certificate was found";
 920                         goto info_done_dealloc;
 921                 }
 922
 923                 /* This is not a real world example, since we only check the first
 924                  * certificate in the given chain.
 925                  */
 926
 927                 ret = gnutls_x509_crt_import(cert, &cert_list[0], GNUTLS_X509_FMT_DER);
 928                 if (ret < 0)
 929                 {
 930                         certinfo->error = gnutls_strerror(ret);
 931                         goto info_done_dealloc;
 932                 }
 933
 934                 if (gnutls_x509_crt_get_dn(cert, name, &name_size) == 0)
 935                 {
 936                         std::string& dn = certinfo->dn;
 937                         dn = name;
 938                         // Make sure there are no chars in the string that we consider invalid
 939                         if (dn.find_first_of("\r\n") != std::string::npos)
 940                                 dn.clear();
 941                 }
 942
 943                 name_size = sizeof(name);
 944                 if (gnutls_x509_crt_get_issuer_dn(cert, name, &name_size) == 0)
 945                 {
 946                         std::string& issuer = certinfo->issuer;
 947                         issuer = name;
 948                         if (issuer.find_first_of("\r\n") != std::string::npos)
 949                                 issuer.clear();
 950                 }
 951
 952                 if ((ret = gnutls_x509_crt_get_fingerprint(cert, hash, digest, &digest_size)) < 0)
 953                 {
 954                         certinfo->error = gnutls_strerror(ret);
 955                 }
 956                 else
 957                 {
 958                         certinfo->fingerprint = irc::hex(digest, digest_size);
 959                 }
 960
 961                 /* Beware here we do not check for errors.
 962                  */
 963                 if ((gnutls_x509_crt_get_expiration_time(cert) < ServerInstance->Time()) || (gnutls_x509_crt_get_activation_time(cert) > ServerInstance->Time()))
 964                 {
 965                         certinfo->error = "Not activated, or expired certificate";
 966                 }
 967
 968 info_done_dealloc:
 969                 gnutls_x509_crt_deinit(cert);
 970         }
 971
 972         void OnEvent(Event& ev)
 973         {
 974                 if (starttls.enabled)
 975                         capHandler.HandleEvent(ev);
 976         }
 977
 978         ModResult OnCheckReady(LocalUser* user)
 979         {
 980                 if ((user->eh.GetIOHook() == this) && (sessions[user->eh.GetFd()].status != ISSL_HANDSHAKEN))
 981                         return MOD_RES_DENY;
 982                 return MOD_RES_PASSTHRU;
 983         }
 984 };
 985
 986 MODULE_INIT(ModuleSSLGnuTLS)