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