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