src/modules/extra/m_ssl_gnutls.cpp

   1 #include <string>
   2 #include <vector>
   3
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <errno.h>
   7 #include <sys/types.h>
   8 #include <sys/socket.h>
   9 #include <netinet/in.h>
  10 #include <arpa/inet.h>
  11 #include <string.h>
  12 #include <unistd.h>
  13
  14 #include <gnutls/gnutls.h>
  15
  16 #include "inspircd_config.h"
  17 #include "users.h"
  18 #include "channels.h"
  19 #include "modules.h"
  20 #include "helperfuncs.h"
  21 #include "socket.h"
  22 #include "hashcomp.h"
  23
  24 /* $ModDesc: Provides SSL support for clients */
  25 /* $CompileFlags: `libgnutls-config --cflags` */
  26 /* $LinkerFlags: `libgnutls-config --libs` */
  27
  28 enum issl_status { ISSL_NONE, ISSL_HANDSHAKING_READ, ISSL_HANDSHAKING_WRITE, ISSL_HANDSHAKEN, ISSL_CLOSING, ISSL_CLOSED };
  29
  30 bool isin(int port, std::vector<int> portlist)
  31 {
  32         for(unsigned int i = 0; i < portlist.size(); i++)
  33                 if(portlist[i] == port)
  34                         return true;
  35
  36         return false;
  37 }
  38
  39 class issl_session
  40 {
  41 public:
  42         gnutls_session_t sess;
  43         issl_status status;
  44         std::string outbuf;
  45         int inbufoffset;
  46         char* inbuf;
  47         int fd;
  48 };
  49
  50 class ModuleSSL : public Module
  51 {
  52         Server* Srv;
  53         ServerConfig* SrvConf;
  54         ConfigReader* Conf;
  55
  56         CullList culllist;
  57
  58         std::vector<int> listenports;
  59
  60         int inbufsize;
  61         issl_session sessions[MAX_DESCRIPTORS];
  62
  63         gnutls_certificate_credentials x509_cred;
  64         gnutls_dh_params dh_params;
  65
  66         std::string keyfile;
  67         std::string certfile;
  68         std::string cafile;
  69         std::string crlfile;
  70         int dh_bits;
  71
  72  public:
  73
  74         ModuleSSL(Server* Me)
  75                 : Module::Module(Me)
  76         {
  77                 Srv = Me;
  78                 SrvConf = Srv->GetConfig();
  79                 Conf = new ConfigReader;
  80
  81                 // Not rehashable...because I cba to reduce all the sizes of existing buffers.
  82                 inbufsize = SrvConf->NetBufferSize;
  83
  84                 gnutls_global_init(); // This must be called once in the program
  85
  86                 if(gnutls_certificate_allocate_credentials(&x509_cred) != 0)
  87                         log(DEFAULT, "m_ssl_gnutls.so: Failed to allocate certificate credentials");
  88
  89                 // Guessing return meaning
  90                 if(gnutls_dh_params_init(&dh_params) < 0)
  91                         log(DEFAULT, "m_ssl_gnutls.so: Failed to initialise DH parameters");
  92
  93                 // Needs the flag as it ignores a plain /rehash
  94                 OnRehash("ssl");
  95
  96                 // Void return, guess we assume success
  97                 gnutls_certificate_set_dh_params(x509_cred, dh_params);
  98         }
  99
 100         virtual void OnRehash(std::string param)
 101         {
 102                 if(param != "ssl")
 103                         return;
 104
 105                 delete Conf;
 106                 Conf = new ConfigReader;
 107
 108                 for(unsigned int i = 0; i < listenports.size(); i++)
 109                 {
 110                         SrvConf->DelIOHook(listenports[i]);
 111                 }
 112
 113                 listenports.clear();
 114
 115                 for(int i = 0; i < Conf->Enumerate("bind"); i++)
 116                 {
 117                         // For each <bind> tag
 118                         if(((Conf->ReadValue("bind", "type", i) == "") || (Conf->ReadValue("bind", "type", i) == "clients")) && (Conf->ReadValue("bind", "ssl", i) == "gnutls"))
 119                         {
 120                                 // Get the port we're meant to be listening on with SSL
 121                                 unsigned int port = Conf->ReadInteger("bind", "port", i, true);
 122                                 SrvConf->AddIOHook(port, this);
 123
 124                                 // We keep a record of which ports we're listening on with SSL
 125                                 listenports.push_back(port);
 126
 127                                 log(DEFAULT, "m_ssl_gnutls.so: Enabling SSL for port %d", port);
 128                         }
 129                 }
 130
 131                 std::string confdir(CONFIG_FILE);
 132                 // +1 so we the path ends with a /
 133                 confdir = confdir.substr(0, confdir.find_last_of('/') + 1);
 134
 135                 cafile  = Conf->ReadValue("gnutls", "cafile", 0);
 136                 crlfile = Conf->ReadValue("gnutls", "crlfile", 0);
 137                 certfile        = Conf->ReadValue("gnutls", "certfile", 0);
 138                 keyfile = Conf->ReadValue("gnutls", "keyfile", 0);
 139                 dh_bits = Conf->ReadInteger("gnutls", "dhbits", 0, false);
 140
 141                 // Set all the default values needed.
 142                 if(cafile == "")
 143                         cafile = "ca.pem";
 144
 145                 if(crlfile == "")
 146                         crlfile = "crl.pem";
 147
 148                 if(certfile == "")
 149                         certfile = "cert.pem";
 150
 151                 if(keyfile == "")
 152                         keyfile = "key.pem";
 153
 154                 if((dh_bits != 768) && (dh_bits != 1024) && (dh_bits != 2048) && (dh_bits != 3072) && (dh_bits != 4096))
 155                         dh_bits = 1024;
 156
 157                 // Prepend relative paths with the path to the config directory.
 158                 if(cafile[0] != '/')
 159                         cafile = confdir + cafile;
 160
 161                 if(crlfile[0] != '/')
 162                         crlfile = confdir + crlfile;
 163
 164                 if(certfile[0] != '/')
 165                         certfile = confdir + certfile;
 166
 167                 if(keyfile[0] != '/')
 168                         keyfile = confdir + keyfile;
 169
 170                 if(gnutls_certificate_set_x509_trust_file(x509_cred, cafile.c_str(), GNUTLS_X509_FMT_PEM) < 0)
 171                         log(DEFAULT, "m_ssl_gnutls.so: Failed to set X.509 trust file: %s", cafile.c_str());
 172
 173                 if(gnutls_certificate_set_x509_crl_file (x509_cred, crlfile.c_str(), GNUTLS_X509_FMT_PEM) < 0)
 174                         log(DEFAULT, "m_ssl_gnutls.so: Failed to set X.509 CRL file: %s", crlfile.c_str());
 175
 176                 // Guessing on the return value of this, manual doesn't say :|
 177                 if(gnutls_certificate_set_x509_key_file (x509_cred, certfile.c_str(), keyfile.c_str(), GNUTLS_X509_FMT_PEM) < 0)
 178                         log(DEFAULT, "m_ssl_gnutls.so: Failed to set X.509 certificate and key files: %s and %s", certfile.c_str(), keyfile.c_str());
 179
 180                 // This may be on a large (once a day or week) timer eventually.
 181                 GenerateDHParams();
 182         }
 183
 184         void GenerateDHParams()
 185         {
 186                 // Generate Diffie Hellman parameters - for use with DHE
 187                 // kx algorithms. These should be discarded and regenerated
 188                 // once a day, once a week or once a month. Depending on the
 189                 // security requirements.
 190
 191                 if(gnutls_dh_params_generate2(dh_params, dh_bits) < 0)
 192                         log(DEFAULT, "m_ssl_gnutls.so: Failed to generate DH parameters (%d bits)", dh_bits);
 193         }
 194
 195         virtual ~ModuleSSL()
 196         {
 197                 delete Conf;
 198                 gnutls_dh_params_deinit(dh_params);
 199                 gnutls_certificate_free_credentials(x509_cred);
 200                 gnutls_global_deinit();
 201         }
 202
 203         virtual void OnCleanup(int target_type, void* item)
 204         {
 205                 if(target_type == TYPE_USER)
 206                 {
 207                         userrec* user = (userrec*)item;
 208
 209                         if(user->GetExt("ssl") && IS_LOCAL(user) && isin(user->port, listenports))
 210                         {
 211                                 // User is using SSL, they're a local user, and they're using one of *our* SSL ports.
 212                                 // Potentially there could be multiple SSL modules loaded at once on different ports.
 213                                 log(DEBUG, "m_ssl_gnutls.so: Adding user %s to cull list", user->nick);
 214                                 culllist.AddItem(user, "SSL module unloading");
 215                         }
 216                 }
 217         }
 218
 219         virtual void OnUnloadModule(Module* mod, std::string name)
 220         {
 221                 if(mod == this)
 222                 {
 223                         // We're being unloaded, kill all the users added to the cull list in OnCleanup
 224                         int numusers = culllist.Apply();
 225                         log(DEBUG, "m_ssl_gnutls.so: Killed %d users for unload of GnuTLS SSL module", numusers);
 226
 227                         for(unsigned int i = 0; i < listenports.size(); i++)
 228                                 SrvConf->DelIOHook(listenports[i]);
 229                 }
 230         }
 231
 232         virtual Version GetVersion()
 233         {
 234                 return Version(1, 0, 0, 0, VF_VENDOR);
 235         }
 236
 237         void Implements(char* List)
 238         {
 239                 List[I_OnRawSocketAccept] = List[I_OnRawSocketClose] = List[I_OnRawSocketRead] = List[I_OnRawSocketWrite] = List[I_OnCleanup] = 1;
 240                 List[I_OnSyncUserMetaData] = List[I_OnDecodeMetaData] = List[I_OnUnloadModule] = List[I_OnRehash] = List[I_OnWhois] = 1;
 241         }
 242
 243         virtual void OnRawSocketAccept(int fd, std::string ip, int localport)
 244         {
 245                 issl_session* session = &sessions[fd];
 246
 247                 session->fd = fd;
 248                 session->inbuf = new char[inbufsize];
 249                 session->inbufoffset = 0;
 250
 251                 gnutls_init(&session->sess, GNUTLS_SERVER);
 252
 253                 gnutls_set_default_priority(session->sess); // Avoid calling all the priority functions, defaults are adequate.
 254                 gnutls_credentials_set(session->sess, GNUTLS_CRD_CERTIFICATE, x509_cred);
 255                 gnutls_certificate_server_set_request(session->sess, GNUTLS_CERT_REQUEST); // Request client certificate if any.
 256                 gnutls_dh_set_prime_bits(session->sess, dh_bits);
 257                 gnutls_transport_set_ptr(session->sess, (gnutls_transport_ptr_t) fd); // Give gnutls the fd for the socket.
 258
 259                 Handshake(session);
 260         }
 261
 262         virtual void OnRawSocketClose(int fd)
 263         {
 264                 log(DEBUG, "OnRawSocketClose: %d", fd);
 265                 CloseSession(&sessions[fd]);
 266         }
 267
 268         virtual int OnRawSocketRead(int fd, char* buffer, unsigned int count, int &readresult)
 269         {
 270                 issl_session* session = &sessions[fd];
 271
 272                 if(!session->sess)
 273                 {
 274                         log(DEBUG, "m_ssl_gnutls.so: OnRawSocketRead: No session to read from");
 275                         readresult = 0;
 276                         CloseSession(session);
 277                         return 1;
 278                 }
 279
 280                 log(DEBUG, "m_ssl_gnutls.so: OnRawSocketRead(%d, buffer, %u, %d)", fd, count, readresult);
 281
 282                 if(session->status == ISSL_HANDSHAKING_READ)
 283                 {
 284                         // The handshake isn't finished, try to finish it.
 285
 286                         if(Handshake(session))
 287                         {
 288                                 // Handshake successfully resumed.
 289                                 log(DEBUG, "m_ssl_gnutls.so: OnRawSocketRead: successfully resumed handshake");
 290                         }
 291                         else
 292                         {
 293                                 // Couldn't resume handshake.
 294                                 log(DEBUG, "m_ssl_gnutls.so: OnRawSocketRead: failed to resume handshake");
 295                                 return -1;
 296                         }
 297                 }
 298                 else if(session->status == ISSL_HANDSHAKING_WRITE)
 299                 {
 300                         log(DEBUG, "m_ssl_gnutls.so: OnRawSocketRead: handshake wants to write data but we are currently reading");
 301                         return -1;
 302                 }
 303
 304                 // If we resumed the handshake then session->status will be ISSL_HANDSHAKEN.
 305
 306                 if(session->status == ISSL_HANDSHAKEN)
 307                 {
 308                         // Is this right? Not sure if the unencrypted data is garaunteed to be the same length.
 309                         // Read into the inbuffer, offset from the beginning by the amount of data we have that insp hasn't taken yet.
 310                         log(DEBUG, "m_ssl_gnutls.so: gnutls_record_recv(sess, inbuf+%d, %d-%d)", session->inbufoffset, inbufsize, session->inbufoffset);
 311
 312                         int ret = gnutls_record_recv(session->sess, session->inbuf + session->inbufoffset, inbufsize - session->inbufoffset);
 313
 314                         if(ret == 0)
 315                         {
 316                                 // Client closed connection.
 317                                 log(DEBUG, "m_ssl_gnutls.so: Client closed the connection");
 318                                 readresult = 0;
 319                                 CloseSession(session);
 320                                 return 1;
 321                         }
 322                         else if(ret < 0)
 323                         {
 324                                 if(ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED)
 325                                 {
 326                                         log(DEBUG, "m_ssl_gnutls.so: OnRawSocketRead: Not all SSL data read: %s", gnutls_strerror(ret));
 327                                         return -1;
 328                                 }
 329                                 else
 330                                 {
 331                                         log(DEBUG, "m_ssl_gnutls.so: OnRawSocketRead: Error reading SSL data: %s", gnutls_strerror(ret));
 332                                         readresult = 0;
 333                                         CloseSession(session);
 334                                 }
 335                         }
 336                         else
 337                         {
 338                                 // Read successfully 'ret' bytes into inbuf + inbufoffset
 339                                 // There are 'ret' + 'inbufoffset' bytes of data in 'inbuf'
 340                                 // 'buffer' is 'count' long
 341
 342                                 unsigned int length = ret + session->inbufoffset;
 343
 344                                 log(DEBUG, "m_ssl_gnutls.so: OnRawSocketRead: Read %d bytes, now have %d waiting to be passed up", ret, length);
 345
 346                                 if(count <= length)
 347                                 {
 348                                         memcpy(buffer, session->inbuf, count);
 349                                         // Move the stuff left in inbuf to the beginning of it
 350                                         memcpy(session->inbuf, session->inbuf + count, (length - count));
 351                                         // Now we need to set session->inbufoffset to the amount of data still waiting to be handed to insp.
 352                                         session->inbufoffset = length - count;
 353                                         // Insp uses readresult as the count of how much data there is in buffer, so:
 354                                         readresult = count;
 355                                 }
 356                                 else
 357                                 {
 358                                         // There's not as much in the inbuf as there is space in the buffer, so just copy the whole thing.
 359                                         memcpy(buffer, session->inbuf, length);
 360                                         // Zero the offset, as there's nothing there..
 361                                         session->inbufoffset = 0;
 362                                         // As above
 363                                         readresult = length;
 364                                 }
 365
 366                                 log(DEBUG, "m_ssl_gnutls.so: OnRawSocketRead: Passing %d bytes up to insp:");
 367                                 Srv->Log(DEBUG, std::string(buffer, readresult));
 368                         }
 369                 }
 370                 else if(session->status == ISSL_CLOSING)
 371                 {
 372                         log(DEBUG, "m_ssl_gnutls.so: OnRawSocketRead: session closing...");
 373                         readresult = 0;
 374                 }
 375
 376                 return 1;
 377         }
 378
 379         virtual int OnRawSocketWrite(int fd, char* buffer, int count)
 380         {
 381                 issl_session* session = &sessions[fd];
 382                 const char* sendbuffer = buffer;
 383
 384                 if(!session->sess)
 385                 {
 386                         log(DEBUG, "m_ssl_gnutls.so: OnRawSocketWrite: No session to write to");
 387                         CloseSession(session);
 388                         return 1;
 389                 }
 390
 391                 if(session->status == ISSL_HANDSHAKING_WRITE)
 392                 {
 393                         // The handshake isn't finished, try to finish it.
 394
 395                         if(Handshake(session))
 396                         {
 397                                 // Handshake successfully resumed.
 398                                 log(DEBUG, "m_ssl_gnutls.so: OnRawSocketWrite: successfully resumed handshake");
 399                         }
 400                         else
 401                         {
 402                                 // Couldn't resume handshake.
 403                                 log(DEBUG, "m_ssl_gnutls.so: OnRawSocketWrite: failed to resume handshake");
 404                         }
 405                 }
 406                 else if(session->status == ISSL_HANDSHAKING_READ)
 407                 {
 408                         log(DEBUG, "m_ssl_gnutls.so: OnRawSocketWrite: handshake wants to read data but we are currently writing");
 409                 }
 410
 411                 log(DEBUG, "m_ssl_gnutls.so: OnRawSocketWrite: Adding %d bytes to the outgoing buffer", count);
 412                 session->outbuf.append(sendbuffer, count);
 413                 sendbuffer = session->outbuf.c_str();
 414                 count = session->outbuf.size();
 415
 416                 if(session->status == ISSL_HANDSHAKEN)
 417                 {
 418                         log(DEBUG, "m_ssl_gnutls.so: OnRawSocketWrite: Trying to write %d bytes:", count);
 419                         Srv->Log(DEBUG, session->outbuf);
 420
 421                         int ret = gnutls_record_send(session->sess, sendbuffer, count);
 422
 423                         if(ret == 0)
 424                         {
 425                                 log(DEBUG, "m_ssl_gnutls.so: OnRawSocketWrite: Client closed the connection");
 426                                 CloseSession(session);
 427                         }
 428                         else if(ret < 0)
 429                         {
 430                                 if(ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED)
 431                                 {
 432                                         log(DEBUG, "m_ssl_gnutls.so: OnRawSocketWrite: Not all SSL data written: %s", gnutls_strerror(ret));
 433                                 }
 434                                 else
 435                                 {
 436                                         log(DEBUG, "m_ssl_gnutls.so: OnRawSocketWrite: Error writing SSL data: %s", gnutls_strerror(ret));
 437                                         CloseSession(session);
 438                                 }
 439                         }
 440                         else
 441                         {
 442                                 log(DEBUG, "m_ssl_gnutls.so: OnRawSocketWrite: Successfully wrote %d bytes", ret);
 443                                 session->outbuf = session->outbuf.substr(ret);
 444                         }
 445                 }
 446                 else if(session->status == ISSL_CLOSING)
 447                 {
 448                         log(DEBUG, "m_ssl_gnutls.so: OnRawSocketWrite: session closing...");
 449                 }
 450
 451                 return 1;
 452         }
 453
 454         // :kenny.chatspike.net 320 Om Epy|AFK :is a Secure Connection
 455         virtual void OnWhois(userrec* source, userrec* dest)
 456         {
 457                 if(dest->GetExt("ssl"))
 458                 {
 459                         WriteServ(source->fd, "320 %s %s :is a Secure Connection", source->nick, dest->nick);
 460                 }
 461         }
 462
 463         virtual void OnSyncUserMetaData(userrec* user, Module* proto, void* opaque, std::string extname)
 464         {
 465                 // check if the linking module wants to know about OUR metadata
 466                 if(extname == "ssl")
 467                 {
 468                         // check if this user has an swhois field to send
 469                         if(user->GetExt(extname))
 470                         {
 471                                 // call this function in the linking module, let it format the data how it
 472                                 // sees fit, and send it on its way. We dont need or want to know how.
 473                                 proto->ProtoSendMetaData(opaque, TYPE_USER, user, extname, "ON");
 474                         }
 475                 }
 476         }
 477
 478         virtual void OnDecodeMetaData(int target_type, void* target, std::string extname, std::string extdata)
 479         {
 480                 // check if its our metadata key, and its associated with a user
 481                 if ((target_type == TYPE_USER) && (extname == "ssl"))
 482                 {
 483                         userrec* dest = (userrec*)target;
 484                         // if they dont already have an ssl flag, accept the remote server's
 485                         if (!dest->GetExt(extname))
 486                         {
 487                                 dest->Extend(extname, "ON");
 488                         }
 489                 }
 490         }
 491
 492         bool Handshake(issl_session* session)
 493         {
 494                 int ret = gnutls_handshake(session->sess);
 495
 496       if(ret < 0)
 497                 {
 498                         if(ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED)
 499                         {
 500                                 // Handshake needs resuming later, read() or write() would have blocked.
 501
 502                                 if(gnutls_record_get_direction(session->sess) == 0)
 503                                 {
 504                                         // gnutls_handshake() wants to read() again.
 505                                         session->status = ISSL_HANDSHAKING_READ;
 506                                         log(DEBUG, "m_ssl_gnutls.so: Handshake needs resuming (reading) later, error string: %s", gnutls_strerror(ret));
 507                                 }
 508                                 else
 509                                 {
 510                                         // gnutls_handshake() wants to write() again.
 511                                         session->status = ISSL_HANDSHAKING_WRITE;
 512                                         log(DEBUG, "m_ssl_gnutls.so: Handshake needs resuming (writing) later, error string: %s", gnutls_strerror(ret));
 513                                         MakePollWrite(session);
 514                                 }
 515                         }
 516                         else
 517                         {
 518                                 // Handshake failed.
 519                                 CloseSession(session);
 520                            log(DEBUG, "m_ssl_gnutls.so: Handshake failed, error string: %s", gnutls_strerror(ret));
 521                            session->status = ISSL_CLOSING;
 522                         }
 523
 524                         return false;
 525                 }
 526                 else
 527                 {
 528                         // Handshake complete.
 529                         log(DEBUG, "m_ssl_gnutls.so: Handshake completed");
 530
 531                         // This will do for setting the ssl flag...it could be done earlier if it's needed. But this seems neater.
 532                         Srv->FindDescriptor(session->fd)->Extend("ssl", "ON");
 533
 534                         session->status = ISSL_HANDSHAKEN;
 535
 536                         MakePollWrite(session);
 537
 538                         return true;
 539                 }
 540         }
 541
 542         void MakePollWrite(issl_session* session)
 543         {
 544                 OnRawSocketWrite(session->fd, NULL, 0);
 545         }
 546
 547         void CloseSession(issl_session* session)
 548         {
 549                 if(session->sess)
 550                 {
 551                         gnutls_bye(session->sess, GNUTLS_SHUT_WR);
 552                         gnutls_deinit(session->sess);
 553                 }
 554
 555                 if(session->inbuf)
 556                 {
 557                         delete[] session->inbuf;
 558                 }
 559
 560                 session->outbuf.clear();
 561                 session->inbuf = NULL;
 562                 session->sess = NULL;
 563                 session->status = ISSL_NONE;
 564         }
 565 };
 566
 567 class ModuleSSLFactory : public ModuleFactory
 568 {
 569  public:
 570         ModuleSSLFactory()
 571         {
 572         }
 573
 574         ~ModuleSSLFactory()
 575         {
 576         }
 577
 578         virtual Module * CreateModule(Server* Me)
 579         {
 580                 return new ModuleSSL(Me);
 581         }
 582 };
 583
 584
 585 extern "C" void * init_module( void )
 586 {
 587         return new ModuleSSLFactory;
 588 }
 589