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 < (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
 206         ModuleSSLGnuTLS()
 207                 : starttls(this), capHandler(this, "tls"), iohook(this, "ssl/gnutls", SERVICE_IOHOOK)
 208         {
 209                 gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
 210
 211                 sessions = new issl_session[ServerInstance->SE->GetMaxFds()];
 212
 213                 gnutls_global_init(); // This must be called once in the program
 214                 gnutls_x509_privkey_init(&x509_key);
 215
 216                 #ifdef GNUTLS_NEW_PRIO_API
 217                 // Init this here so it's always initialized, avoids an extra boolean
 218                 gnutls_priority_init(&priority, "NORMAL", NULL);
 219                 #endif
 220
 221                 cred_alloc = false;
 222                 dh_alloc = false;
 223         }
 224
 225         void init()
 226         {
 227                 // Needs the flag as it ignores a plain /rehash
 228                 OnModuleRehash(NULL,"ssl");
 229
 230                 ServerInstance->GenRandom = &randhandler;
 231
 232                 // Void return, guess we assume success
 233                 gnutls_certificate_set_dh_params(x509_cred, dh_params);
 234                 Implementation eventlist[] = { I_On005Numeric, I_OnRehash, I_OnModuleRehash, I_OnUserConnect,
 235                         I_OnEvent, I_OnHookIO };
 236                 ServerInstance->Modules->Attach(eventlist, this, sizeof(eventlist)/sizeof(Implementation));
 237
 238                 ServerInstance->Modules->AddService(iohook);
 239                 ServerInstance->Modules->AddService(starttls);
 240         }
 241
 242         void OnRehash(User* user)
 243         {
 244                 sslports.clear();
 245
 246                 ConfigTag* Conf = ServerInstance->Config->ConfValue("gnutls");
 247                 starttls.enabled = Conf->getBool("starttls", true);
 248
 249                 if (Conf->getBool("showports", true))
 250                 {
 251                         sslports = Conf->getString("advertisedports");
 252                         if (!sslports.empty())
 253                                 return;
 254
 255                         for (size_t i = 0; i < ServerInstance->ports.size(); i++)
 256                         {
 257                                 ListenSocket* port = ServerInstance->ports[i];
 258                                 if (port->bind_tag->getString("ssl") != "gnutls")
 259                                         continue;
 260
 261                                 const std::string& portid = port->bind_desc;
 262                                 ServerInstance->Logs->Log("m_ssl_gnutls", DEFAULT, "m_ssl_gnutls.so: Enabling SSL for port %s", portid.c_str());
 263
 264                                 if (port->bind_tag->getString("type", "clients") == "clients" && port->bind_addr != "127.0.0.1")
 265                                 {
 266                                         /*
 267                                          * Found an SSL port for clients that is not bound to 127.0.0.1 and handled by us, display
 268                                          * the IP:port in ISUPPORT.
 269                                          *
 270                                          * We used to advertise all ports seperated by a ';' char that matched the above criteria,
 271                                          * but this resulted in too long ISUPPORT lines if there were lots of ports to be displayed.
 272                                          * To solve this by default we now only display the first IP:port found and let the user
 273                                          * configure the exact value for the 005 token, if necessary.
 274                                          */
 275                                         sslports = portid;
 276                                         break;
 277                                 }
 278                         }
 279                 }
 280         }
 281
 282         void OnModuleRehash(User* user, const std::string &param)
 283         {
 284                 if(param != "ssl")
 285                         return;
 286
 287                 std::string keyfile;
 288                 std::string certfile;
 289                 std::string cafile;
 290                 std::string crlfile;
 291                 OnRehash(user);
 292
 293                 ConfigTag* Conf = ServerInstance->Config->ConfValue("gnutls");
 294
 295                 cafile = Conf->getString("cafile", CONFIG_PATH "/ca.pem");
 296                 crlfile = Conf->getString("crlfile", CONFIG_PATH "/crl.pem");
 297                 certfile = Conf->getString("certfile", CONFIG_PATH "/cert.pem");
 298                 keyfile = Conf->getString("keyfile", CONFIG_PATH "/key.pem");
 299                 dh_bits = Conf->getInt("dhbits");
 300                 std::string hashname = Conf->getString("hash", "md5");
 301
 302                 // The GnuTLS manual states that the gnutls_set_default_priority()
 303                 // call we used previously when initializing the session is the same
 304                 // as setting the "NORMAL" priority string.
 305                 // Thus if the setting below is not in the config we will behave exactly
 306                 // the same as before, when the priority setting wasn't available.
 307                 std::string priorities = Conf->getString("priority", "NORMAL");
 308
 309                 if((dh_bits != 768) && (dh_bits != 1024) && (dh_bits != 2048) && (dh_bits != 3072) && (dh_bits != 4096))
 310                         dh_bits = 1024;
 311
 312                 if (hashname == "md5")
 313                         hash = GNUTLS_DIG_MD5;
 314                 else if (hashname == "sha1")
 315                         hash = GNUTLS_DIG_SHA1;
 316                 else
 317                         throw ModuleException("Unknown hash type " + hashname);
 318
 319
 320                 int ret;
 321
 322                 if (dh_alloc)
 323                 {
 324                         gnutls_dh_params_deinit(dh_params);
 325                         dh_alloc = false;
 326                 }
 327
 328                 if (cred_alloc)
 329                 {
 330                         // Deallocate the old credentials
 331                         gnutls_certificate_free_credentials(x509_cred);
 332
 333                         for(unsigned int i=0; i < x509_certs.size(); i++)
 334                                 gnutls_x509_crt_deinit(x509_certs[i]);
 335                         x509_certs.clear();
 336                 }
 337
 338                 ret = gnutls_certificate_allocate_credentials(&x509_cred);
 339                 cred_alloc = (ret >= 0);
 340                 if (!cred_alloc)
 341                         ServerInstance->Logs->Log("m_ssl_gnutls",DEBUG, "m_ssl_gnutls.so: Failed to allocate certificate credentials: %s", gnutls_strerror(ret));
 342
 343                 if((ret =gnutls_certificate_set_x509_trust_file(x509_cred, cafile.c_str(), GNUTLS_X509_FMT_PEM)) < 0)
 344                         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));
 345
 346                 if((ret = gnutls_certificate_set_x509_crl_file (x509_cred, crlfile.c_str(), GNUTLS_X509_FMT_PEM)) < 0)
 347                         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));
 348
 349                 FileReader reader;
 350
 351                 reader.LoadFile(certfile);
 352                 std::string cert_string = reader.Contents();
 353                 gnutls_datum_t cert_datum = { (unsigned char*)cert_string.data(), static_cast<unsigned int>(cert_string.length()) };
 354
 355                 reader.LoadFile(keyfile);
 356                 std::string key_string = reader.Contents();
 357                 gnutls_datum_t key_datum = { (unsigned char*)key_string.data(), static_cast<unsigned int>(key_string.length()) };
 358
 359                 // If this fails, no SSL port will work. At all. So, do the smart thing - throw a ModuleException
 360                 unsigned int certcount = 3;
 361                 x509_certs.resize(certcount);
 362                 ret = gnutls_x509_crt_list_import(&x509_certs[0], &certcount, &cert_datum, GNUTLS_X509_FMT_PEM, GNUTLS_X509_CRT_LIST_IMPORT_FAIL_IF_EXCEED);
 363                 if (ret == GNUTLS_E_SHORT_MEMORY_BUFFER)
 364                 {
 365                         // 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
 366                         x509_certs.resize(certcount);
 367                         ret = gnutls_x509_crt_list_import(&x509_certs[0], &certcount, &cert_datum, GNUTLS_X509_FMT_PEM, GNUTLS_X509_CRT_LIST_IMPORT_FAIL_IF_EXCEED);
 368                 }
 369
 370                 if (ret <= 0)
 371                 {
 372                         // clear the vector so we won't call gnutls_x509_crt_deinit() on the (uninited) certs later
 373                         x509_certs.clear();
 374                         throw ModuleException("Unable to load GnuTLS server certificate (" + certfile + "): " + ((ret < 0) ? (std::string(gnutls_strerror(ret))) : "No certs could be read"));
 375                 }
 376                 x509_certs.resize(ret);
 377
 378                 if((ret = gnutls_x509_privkey_import(x509_key, &key_datum, GNUTLS_X509_FMT_PEM)) < 0)
 379                         throw ModuleException("Unable to load GnuTLS server private key (" + keyfile + "): " + std::string(gnutls_strerror(ret)));
 380
 381                 if((ret = gnutls_certificate_set_x509_key(x509_cred, &x509_certs[0], certcount, x509_key)) < 0)
 382                         throw ModuleException("Unable to set GnuTLS cert/key pair: " + std::string(gnutls_strerror(ret)));
 383
 384                 #ifdef GNUTLS_NEW_PRIO_API
 385                 // It's safe to call this every time as we cannot have this uninitialized, see constructor and below.
 386                 gnutls_priority_deinit(priority);
 387
 388                 // Try to set the priorities for ciphers, kex methods etc. to the user supplied string
 389                 // If the user did not supply anything then the string is already set to "NORMAL"
 390                 const char* priocstr = priorities.c_str();
 391                 const char* prioerror;
 392
 393                 if ((ret = gnutls_priority_init(&priority, priocstr, &prioerror)) < 0)
 394                 {
 395                         // gnutls did not understand the user supplied string, log and fall back to the default priorities
 396                         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));
 397                         gnutls_priority_init(&priority, "NORMAL", NULL);
 398                 }
 399
 400                 #else
 401                 if (priorities != "NORMAL")
 402                         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.");
 403                 #endif
 404
 405                 #if(GNUTLS_VERSION_MAJOR < 2 || ( GNUTLS_VERSION_MAJOR == 2 && GNUTLS_VERSION_MINOR < 12 ) )
 406                 gnutls_certificate_client_set_retrieve_function (x509_cred, cert_callback);
 407                 #else
 408                 gnutls_certificate_set_retrieve_function (x509_cred, cert_callback);
 409                 #endif
 410                 ret = gnutls_dh_params_init(&dh_params);
 411                 dh_alloc = (ret >= 0);
 412                 if (!dh_alloc)
 413                         ServerInstance->Logs->Log("m_ssl_gnutls",DEFAULT, "m_ssl_gnutls.so: Failed to initialise DH parameters: %s", gnutls_strerror(ret));
 414
 415                 // This may be on a large (once a day or week) timer eventually.
 416                 GenerateDHParams();
 417         }
 418
 419         void GenerateDHParams()
 420         {
 421                 // Generate Diffie Hellman parameters - for use with DHE
 422                 // kx algorithms. These should be discarded and regenerated
 423                 // once a day, once a week or once a month. Depending on the
 424                 // security requirements.
 425
 426                 if (!dh_alloc)
 427                         return;
 428
 429                 int ret;
 430
 431                 if((ret = gnutls_dh_params_generate2(dh_params, dh_bits)) < 0)
 432                         ServerInstance->Logs->Log("m_ssl_gnutls",DEFAULT, "m_ssl_gnutls.so: Failed to generate DH parameters (%d bits): %s", dh_bits, gnutls_strerror(ret));
 433         }
 434
 435         ~ModuleSSLGnuTLS()
 436         {
 437                 for(unsigned int i=0; i < x509_certs.size(); i++)
 438                         gnutls_x509_crt_deinit(x509_certs[i]);
 439
 440                 gnutls_x509_privkey_deinit(x509_key);
 441                 #ifdef GNUTLS_NEW_PRIO_API
 442                 gnutls_priority_deinit(priority);
 443                 #endif
 444
 445                 if (dh_alloc)
 446                         gnutls_dh_params_deinit(dh_params);
 447                 if (cred_alloc)
 448                         gnutls_certificate_free_credentials(x509_cred);
 449
 450                 gnutls_global_deinit();
 451                 delete[] sessions;
 452                 ServerInstance->GenRandom = &ServerInstance->HandleGenRandom;
 453         }
 454
 455         void OnCleanup(int target_type, void* item)
 456         {
 457                 if(target_type == TYPE_USER)
 458                 {
 459                         LocalUser* user = IS_LOCAL(static_cast<User*>(item));
 460
 461                         if (user && user->eh.GetIOHook() == this)
 462                         {
 463                                 // User is using SSL, they're a local user, and they're using one of *our* SSL ports.
 464                                 // Potentially there could be multiple SSL modules loaded at once on different ports.
 465                                 ServerInstance->Users->QuitUser(user, "SSL module unloading");
 466                         }
 467                 }
 468         }
 469
 470         Version GetVersion()
 471         {
 472                 return Version("Provides SSL support for clients", VF_VENDOR);
 473         }
 474
 475
 476         void On005Numeric(std::string &output)
 477         {
 478                 if (!sslports.empty())
 479                         output.append(" SSL=" + sslports);
 480                 if (starttls.enabled)
 481                         output.append(" STARTTLS");
 482         }
 483
 484         void OnHookIO(StreamSocket* user, ListenSocket* lsb)
 485         {
 486                 if (!user->GetIOHook() && lsb->bind_tag->getString("ssl") == "gnutls")
 487                 {
 488                         /* Hook the user with our module */
 489                         user->AddIOHook(this);
 490                 }
 491         }
 492
 493         void OnRequest(Request& request)
 494         {
 495                 if (strcmp("GET_SSL_CERT", request.id) == 0)
 496                 {
 497                         SocketCertificateRequest& req = static_cast<SocketCertificateRequest&>(request);
 498                         int fd = req.sock->GetFd();
 499                         issl_session* session = &sessions[fd];
 500
 501                         req.cert = session->cert;
 502                 }
 503         }
 504
 505         void InitSession(StreamSocket* user, bool me_server)
 506         {
 507                 issl_session* session = &sessions[user->GetFd()];
 508
 509                 gnutls_init(&session->sess, me_server ? GNUTLS_SERVER : GNUTLS_CLIENT);
 510
 511                 #ifdef GNUTLS_NEW_PRIO_API
 512                 gnutls_priority_set(session->sess, priority);
 513                 #endif
 514                 gnutls_credentials_set(session->sess, GNUTLS_CRD_CERTIFICATE, x509_cred);
 515                 gnutls_dh_set_prime_bits(session->sess, dh_bits);
 516                 gnutls_transport_set_ptr(session->sess, reinterpret_cast<gnutls_transport_ptr_t>(user));
 517                 gnutls_transport_set_push_function(session->sess, gnutls_push_wrapper);
 518                 gnutls_transport_set_pull_function(session->sess, gnutls_pull_wrapper);
 519
 520                 if (me_server)
 521                         gnutls_certificate_server_set_request(session->sess, GNUTLS_CERT_REQUEST); // Request client certificate if any.
 522
 523                 Handshake(session, user);
 524         }
 525
 526         void OnStreamSocketAccept(StreamSocket* user, irc::sockets::sockaddrs* client, irc::sockets::sockaddrs* server)
 527         {
 528                 issl_session* session = &sessions[user->GetFd()];
 529
 530                 /* For STARTTLS: Don't try and init a session on a socket that already has a session */
 531                 if (session->sess)
 532                         return;
 533
 534                 InitSession(user, true);
 535         }
 536
 537         void OnStreamSocketConnect(StreamSocket* user)
 538         {
 539                 InitSession(user, false);
 540         }
 541
 542         void OnStreamSocketClose(StreamSocket* user)
 543         {
 544                 CloseSession(&sessions[user->GetFd()]);
 545         }
 546
 547         int OnStreamSocketRead(StreamSocket* user, std::string& recvq)
 548         {
 549                 issl_session* session = &sessions[user->GetFd()];
 550
 551                 if (!session->sess)
 552                 {
 553                         CloseSession(session);
 554                         user->SetError("No SSL session");
 555                         return -1;
 556                 }
 557
 558                 if (session->status == ISSL_HANDSHAKING_READ || session->status == ISSL_HANDSHAKING_WRITE)
 559                 {
 560                         // The handshake isn't finished, try to finish it.
 561
 562                         if(!Handshake(session, user))
 563                         {
 564                                 if (session->status != ISSL_CLOSING)
 565                                         return 0;
 566                                 return -1;
 567                         }
 568                 }
 569
 570                 // If we resumed the handshake then session->status will be ISSL_HANDSHAKEN.
 571
 572                 if (session->status == ISSL_HANDSHAKEN)
 573                 {
 574                         char* buffer = ServerInstance->GetReadBuffer();
 575                         size_t bufsiz = ServerInstance->Config->NetBufferSize;
 576                         int ret = gnutls_record_recv(session->sess, buffer, bufsiz);
 577                         if (ret > 0)
 578                         {
 579                                 recvq.append(buffer, ret);
 580                                 return 1;
 581                         }
 582                         else if (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED)
 583                         {
 584                                 return 0;
 585                         }
 586                         else if (ret == 0)
 587                         {
 588                                 user->SetError("Connection closed");
 589                                 CloseSession(session);
 590                                 return -1;
 591                         }
 592                         else
 593                         {
 594                                 user->SetError(gnutls_strerror(ret));
 595                                 CloseSession(session);
 596                                 return -1;
 597                         }
 598                 }
 599                 else if (session->status == ISSL_CLOSING)
 600                         return -1;
 601
 602                 return 0;
 603         }
 604
 605         int OnStreamSocketWrite(StreamSocket* user, std::string& sendq)
 606         {
 607                 issl_session* session = &sessions[user->GetFd()];
 608
 609                 if (!session->sess)
 610                 {
 611                         CloseSession(session);
 612                         user->SetError("No SSL session");
 613                         return -1;
 614                 }
 615
 616                 if (session->status == ISSL_HANDSHAKING_WRITE || session->status == ISSL_HANDSHAKING_READ)
 617                 {
 618                         // The handshake isn't finished, try to finish it.
 619                         Handshake(session, user);
 620                         if (session->status != ISSL_CLOSING)
 621                                 return 0;
 622                         return -1;
 623                 }
 624
 625                 int ret = 0;
 626
 627                 if (session->status == ISSL_HANDSHAKEN)
 628                 {
 629                         ret = gnutls_record_send(session->sess, sendq.data(), sendq.length());
 630
 631                         if (ret == (int)sendq.length())
 632                         {
 633                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_NO_WRITE);
 634                                 return 1;
 635                         }
 636                         else if (ret > 0)
 637                         {
 638                                 sendq = sendq.substr(ret);
 639                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_SINGLE_WRITE);
 640                                 return 0;
 641                         }
 642                         else if (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED || ret == 0)
 643                         {
 644                                 ServerInstance->SE->ChangeEventMask(user, FD_WANT_SINGLE_WRITE);
 645                                 return 0;
 646                         }
 647                         else // (ret < 0)
 648                         {
 649                                 user->SetError(gnutls_strerror(ret));
 650                                 CloseSession(session);
 651                                 return -1;
 652                         }
 653                 }
 654
 655                 return 0;
 656         }
 657
 658         bool Handshake(issl_session* session, StreamSocket* user)
 659         {
 660                 int ret = gnutls_handshake(session->sess);
 661
 662                 if (ret < 0)
 663                 {
 664                         if(ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED)
 665                         {
 666                                 // Handshake needs resuming later, read() or write() would have blocked.
 667
 668                                 if(gnutls_record_get_direction(session->sess) == 0)
 669                                 {
 670                                         // gnutls_handshake() wants to read() again.
 671                                         session->status = ISSL_HANDSHAKING_READ;
 672                                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_POLL_READ | FD_WANT_NO_WRITE);
 673                                 }
 674                                 else
 675                                 {
 676                                         // gnutls_handshake() wants to write() again.
 677                                         session->status = ISSL_HANDSHAKING_WRITE;
 678                                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_NO_READ | FD_WANT_SINGLE_WRITE);
 679                                 }
 680                         }
 681                         else
 682                         {
 683                                 user->SetError("Handshake Failed - " + std::string(gnutls_strerror(ret)));
 684                                 CloseSession(session);
 685                                 session->status = ISSL_CLOSING;
 686                         }
 687
 688                         return false;
 689                 }
 690                 else
 691                 {
 692                         // Change the seesion state
 693                         session->status = ISSL_HANDSHAKEN;
 694
 695                         VerifyCertificate(session,user);
 696
 697                         // Finish writing, if any left
 698                         ServerInstance->SE->ChangeEventMask(user, FD_WANT_POLL_READ | FD_WANT_NO_WRITE | FD_ADD_TRIAL_WRITE);
 699
 700                         return true;
 701                 }
 702         }
 703
 704         void OnUserConnect(LocalUser* user)
 705         {
 706                 if (user->eh.GetIOHook() == this)
 707                 {
 708                         if (sessions[user->eh.GetFd()].sess)
 709                         {
 710                                 const gnutls_session_t& sess = sessions[user->eh.GetFd()].sess;
 711                                 std::string cipher = UnknownIfNULL(gnutls_kx_get_name(gnutls_kx_get(sess)));
 712                                 cipher.append("-").append(UnknownIfNULL(gnutls_cipher_get_name(gnutls_cipher_get(sess)))).append("-");
 713                                 cipher.append(UnknownIfNULL(gnutls_mac_get_name(gnutls_mac_get(sess))));
 714
 715                                 ssl_cert* cert = sessions[user->eh.GetFd()].cert;
 716                                 if (cert->fingerprint.empty())
 717                                         user->WriteServ("NOTICE %s :*** You are connected using SSL cipher \"%s\"", user->nick.c_str(), cipher.c_str());
 718                                 else
 719                                         user->WriteServ("NOTICE %s :*** You are connected using SSL cipher \"%s\""
 720                                                 " and your SSL fingerprint is %s", user->nick.c_str(), cipher.c_str(), cert->fingerprint.c_str());
 721                         }
 722                 }
 723         }
 724
 725         void CloseSession(issl_session* session)
 726         {
 727                 if (session->sess)
 728                 {
 729                         gnutls_bye(session->sess, GNUTLS_SHUT_WR);
 730                         gnutls_deinit(session->sess);
 731                 }
 732                 session->sess = NULL;
 733                 session->cert = NULL;
 734                 session->status = ISSL_NONE;
 735         }
 736
 737         void VerifyCertificate(issl_session* session, StreamSocket* user)
 738         {
 739                 if (!session->sess || !user)
 740                         return;
 741
 742                 unsigned int status;
 743                 const gnutls_datum_t* cert_list;
 744                 int ret;
 745                 unsigned int cert_list_size;
 746                 gnutls_x509_crt_t cert;
 747                 char name[MAXBUF];
 748                 unsigned char digest[MAXBUF];
 749                 size_t digest_size = sizeof(digest);
 750                 size_t name_size = sizeof(name);
 751                 ssl_cert* certinfo = new ssl_cert;
 752                 session->cert = certinfo;
 753
 754                 /* This verification function uses the trusted CAs in the credentials
 755                  * structure. So you must have installed one or more CA certificates.
 756                  */
 757                 ret = gnutls_certificate_verify_peers2(session->sess, &status);
 758
 759                 if (ret < 0)
 760                 {
 761                         certinfo->error = std::string(gnutls_strerror(ret));
 762                         return;
 763                 }
 764
 765                 certinfo->invalid = (status & GNUTLS_CERT_INVALID);
 766                 certinfo->unknownsigner = (status & GNUTLS_CERT_SIGNER_NOT_FOUND);
 767                 certinfo->revoked = (status & GNUTLS_CERT_REVOKED);
 768                 certinfo->trusted = !(status & GNUTLS_CERT_SIGNER_NOT_CA);
 769
 770                 /* Up to here the process is the same for X.509 certificates and
 771                  * OpenPGP keys. From now on X.509 certificates are assumed. This can
 772                  * be easily extended to work with openpgp keys as well.
 773                  */
 774                 if (gnutls_certificate_type_get(session->sess) != GNUTLS_CRT_X509)
 775                 {
 776                         certinfo->error = "No X509 keys sent";
 777                         return;
 778                 }
 779
 780                 ret = gnutls_x509_crt_init(&cert);
 781                 if (ret < 0)
 782                 {
 783                         certinfo->error = gnutls_strerror(ret);
 784                         return;
 785                 }
 786
 787                 cert_list_size = 0;
 788                 cert_list = gnutls_certificate_get_peers(session->sess, &cert_list_size);
 789                 if (cert_list == NULL)
 790                 {
 791                         certinfo->error = "No certificate was found";
 792                         goto info_done_dealloc;
 793                 }
 794
 795                 /* This is not a real world example, since we only check the first
 796                  * certificate in the given chain.
 797                  */
 798
 799                 ret = gnutls_x509_crt_import(cert, &cert_list[0], GNUTLS_X509_FMT_DER);
 800                 if (ret < 0)
 801                 {
 802                         certinfo->error = gnutls_strerror(ret);
 803                         goto info_done_dealloc;
 804                 }
 805
 806                 gnutls_x509_crt_get_dn(cert, name, &name_size);
 807                 certinfo->dn = name;
 808
 809                 gnutls_x509_crt_get_issuer_dn(cert, name, &name_size);
 810                 certinfo->issuer = name;
 811
 812                 if ((ret = gnutls_x509_crt_get_fingerprint(cert, hash, digest, &digest_size)) < 0)
 813                 {
 814                         certinfo->error = gnutls_strerror(ret);
 815                 }
 816                 else
 817                 {
 818                         certinfo->fingerprint = irc::hex(digest, digest_size);
 819                 }
 820
 821                 /* Beware here we do not check for errors.
 822                  */
 823                 if ((gnutls_x509_crt_get_expiration_time(cert) < ServerInstance->Time()) || (gnutls_x509_crt_get_activation_time(cert) > ServerInstance->Time()))
 824                 {
 825                         certinfo->error = "Not activated, or expired certificate";
 826                 }
 827
 828 info_done_dealloc:
 829                 gnutls_x509_crt_deinit(cert);
 830         }
 831
 832         void OnEvent(Event& ev)
 833         {
 834                 if (starttls.enabled)
 835                         capHandler.HandleEvent(ev);
 836         }
 837 };
 838
 839 MODULE_INIT(ModuleSSLGnuTLS)