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