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