src/modules/extra/m_ssl_gnutls.cpp

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