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