src/modules/extra/m_ssl_mbedtls.cpp

   1 /*
   2  * InspIRCd -- Internet Relay Chat Daemon
   3  *
   4  *   Copyright (C) 2016 Attila Molnar <attilamolnar@hush.com>
   5  *
   6  * This file is part of InspIRCd.  InspIRCd is free software: you can
   7  * redistribute it and/or modify it under the terms of the GNU General Public
   8  * License as published by the Free Software Foundation, version 2.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  12  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  13  * details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19
  20 /* $LinkerFlags: -lmbedtls */
  21
  22 #include "inspircd.h"
  23 #include "modules/ssl.h"
  24
  25 #include <mbedtls/ctr_drbg.h>
  26 #include <mbedtls/dhm.h>
  27 #include <mbedtls/ecp.h>
  28 #include <mbedtls/entropy.h>
  29 #include <mbedtls/error.h>
  30 #include <mbedtls/md.h>
  31 #include <mbedtls/pk.h>
  32 #include <mbedtls/ssl.h>
  33 #include <mbedtls/ssl_ciphersuites.h>
  34 #include <mbedtls/version.h>
  35 #include <mbedtls/x509.h>
  36 #include <mbedtls/x509_crt.h>
  37 #include <mbedtls/x509_crl.h>
  38
  39 #ifdef INSPIRCD_MBEDTLS_LIBRARY_DEBUG
  40 #include <mbedtls/debug.h>
  41 #endif
  42
  43 namespace mbedTLS
  44 {
  45         class Exception : public ModuleException
  46         {
  47          public:
  48                 Exception(const std::string& reason)
  49                         : ModuleException(reason) { }
  50         };
  51
  52         std::string ErrorToString(int errcode)
  53         {
  54                 char buf[256];
  55                 mbedtls_strerror(errcode, buf, sizeof(buf));
  56                 return buf;
  57         }
  58
  59         void ThrowOnError(int errcode, const char* msg)
  60         {
  61                 if (errcode != 0)
  62                 {
  63                         std::string reason = msg;
  64                         reason.append(" :").append(ErrorToString(errcode));
  65                         throw Exception(reason);
  66                 }
  67         }
  68
  69         template <typename T, void (*init)(T*), void (*deinit)(T*)>
  70         class RAIIObj
  71         {
  72                 T obj;
  73
  74          public:
  75                 RAIIObj()
  76                 {
  77                         init(&obj);
  78                 }
  79
  80                 ~RAIIObj()
  81                 {
  82                         deinit(&obj);
  83                 }
  84
  85                 T* get() { return &obj; }
  86                 const T* get() const { return &obj; }
  87         };
  88
  89         typedef RAIIObj<mbedtls_entropy_context, mbedtls_entropy_init, mbedtls_entropy_free> Entropy;
  90
  91         class CTRDRBG : private RAIIObj<mbedtls_ctr_drbg_context, mbedtls_ctr_drbg_init, mbedtls_ctr_drbg_free>
  92         {
  93          public:
  94                 bool Seed(Entropy& entropy)
  95                 {
  96                         return (mbedtls_ctr_drbg_seed(get(), mbedtls_entropy_func, entropy.get(), NULL, 0) == 0);
  97                 }
  98
  99                 void SetupConf(mbedtls_ssl_config* conf)
 100                 {
 101                         mbedtls_ssl_conf_rng(conf, mbedtls_ctr_drbg_random, get());
 102                 }
 103         };
 104
 105         class DHParams : public RAIIObj<mbedtls_dhm_context, mbedtls_dhm_init, mbedtls_dhm_free>
 106         {
 107          public:
 108                 void set(const std::string& dhstr)
 109                 {
 110                         // Last parameter is buffer size, must include the terminating null
 111                         int ret = mbedtls_dhm_parse_dhm(get(), reinterpret_cast<const unsigned char*>(dhstr.c_str()), dhstr.size()+1);
 112                         ThrowOnError(ret, "Unable to import DH params");
 113                 }
 114         };
 115
 116         class X509Key : public RAIIObj<mbedtls_pk_context, mbedtls_pk_init, mbedtls_pk_free>
 117         {
 118          public:
 119                 /** Import */
 120                 X509Key(const std::string& keystr)
 121                 {
 122                         int ret = mbedtls_pk_parse_key(get(), reinterpret_cast<const unsigned char*>(keystr.c_str()), keystr.size()+1, NULL, 0);
 123                         ThrowOnError(ret, "Unable to import private key");
 124                 }
 125         };
 126
 127         class Ciphersuites
 128         {
 129                 std::vector<int> list;
 130
 131          public:
 132                 Ciphersuites(const std::string& str)
 133                 {
 134                         // mbedTLS uses the ciphersuite format "TLS-ECDHE-RSA-WITH-AES-128-GCM-SHA256" internally.
 135                         // This is a bit verbose, so we make life a bit simpler for admins by not requiring them to supply the static parts.
 136                         irc::sepstream ss(str, ':');
 137                         for (std::string token; ss.GetToken(token); )
 138                         {
 139                                 // Prepend "TLS-" if not there
 140                                 if (token.compare(0, 4, "TLS-", 4))
 141                                         token.insert(0, "TLS-");
 142
 143                                 const int id = mbedtls_ssl_get_ciphersuite_id(token.c_str());
 144                                 if (!id)
 145                                         throw Exception("Unknown ciphersuite " + token);
 146                                 list.push_back(id);
 147                         }
 148                         list.push_back(0);
 149                 }
 150
 151                 const int* get() const { return &list.front(); }
 152                 bool empty() const { return (list.size() <= 1); }
 153         };
 154
 155         class Curves
 156         {
 157                 std::vector<mbedtls_ecp_group_id> list;
 158
 159          public:
 160                 Curves(const std::string& str)
 161                 {
 162                         irc::sepstream ss(str, ':');
 163                         for (std::string token; ss.GetToken(token); )
 164                         {
 165                                 const mbedtls_ecp_curve_info* curve = mbedtls_ecp_curve_info_from_name(token.c_str());
 166                                 if (!curve)
 167                                         throw Exception("Unknown curve " + token);
 168                                 list.push_back(curve->grp_id);
 169                         }
 170                         list.push_back(MBEDTLS_ECP_DP_NONE);
 171                 }
 172
 173                 const mbedtls_ecp_group_id* get() const { return &list.front(); }
 174                 bool empty() const { return (list.size() <= 1); }
 175         };
 176
 177         class X509CertList : public RAIIObj<mbedtls_x509_crt, mbedtls_x509_crt_init, mbedtls_x509_crt_free>
 178         {
 179          public:
 180                 /** Import or create empty */
 181                 X509CertList(const std::string& certstr, bool allowempty = false)
 182                 {
 183                         if ((allowempty) && (certstr.empty()))
 184                                 return;
 185                         int ret = mbedtls_x509_crt_parse(get(), reinterpret_cast<const unsigned char*>(certstr.c_str()), certstr.size()+1);
 186                         ThrowOnError(ret, "Unable to load certificates");
 187                 }
 188
 189                 bool empty() const { return (get()->raw.p != NULL); }
 190         };
 191
 192         class X509CRL : public RAIIObj<mbedtls_x509_crl, mbedtls_x509_crl_init, mbedtls_x509_crl_free>
 193         {
 194          public:
 195                 X509CRL(const std::string& crlstr)
 196                 {
 197                         if (crlstr.empty())
 198                                 return;
 199                         int ret = mbedtls_x509_crl_parse(get(), reinterpret_cast<const unsigned char*>(crlstr.c_str()), crlstr.size()+1);
 200                         ThrowOnError(ret, "Unable to load CRL");
 201                 }
 202         };
 203
 204         class X509Credentials
 205         {
 206                 /** Private key
 207                  */
 208                 X509Key key;
 209
 210                 /** Certificate list, presented to the peer
 211                  */
 212                 X509CertList certs;
 213
 214          public:
 215                 X509Credentials(const std::string& certstr, const std::string& keystr)
 216                         : key(keystr)
 217                         , certs(certstr)
 218                 {
 219                         // Verify that one of the certs match the private key
 220                         bool found = false;
 221                         for (mbedtls_x509_crt* cert = certs.get(); cert; cert = cert->next)
 222                         {
 223                                 if (mbedtls_pk_check_pair(&cert->pk, key.get()) == 0)
 224                                 {
 225                                         found = true;
 226                                         break;
 227                                 }
 228                         }
 229                         if (!found)
 230                                 throw Exception("Public/private key pair does not match");
 231                 }
 232
 233                 mbedtls_pk_context* getkey() { return key.get(); }
 234                 mbedtls_x509_crt* getcerts() { return certs.get(); }
 235         };
 236
 237         class Context
 238         {
 239                 mbedtls_ssl_config conf;
 240
 241 #ifdef INSPIRCD_MBEDTLS_LIBRARY_DEBUG
 242                 static void DebugLogFunc(void* userptr, int level, const char* file, int line, const char* msg)
 243                 {
 244                         // Remove trailing \n
 245                         size_t len = strlen(msg);
 246                         if ((len > 0) && (msg[len-1] == '\n'))
 247                                 len--;
 248                         ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "%s:%d %.*s", file, line, len, msg);
 249                 }
 250 #endif
 251
 252          public:
 253                 Context(CTRDRBG& ctrdrbg, unsigned int endpoint)
 254                 {
 255                         mbedtls_ssl_config_init(&conf);
 256 #ifdef INSPIRCD_MBEDTLS_LIBRARY_DEBUG
 257                         mbedtls_debug_set_threshold(INT_MAX);
 258                         mbedtls_ssl_conf_dbg(&conf, DebugLogFunc, NULL);
 259 #endif
 260                         mbedtls_ssl_conf_authmode(&conf, MBEDTLS_SSL_VERIFY_OPTIONAL);
 261
 262                         // TODO: check ret of mbedtls_ssl_config_defaults
 263                         mbedtls_ssl_config_defaults(&conf, endpoint, MBEDTLS_SSL_TRANSPORT_STREAM, MBEDTLS_SSL_PRESET_DEFAULT);
 264                         ctrdrbg.SetupConf(&conf);
 265                 }
 266
 267                 ~Context()
 268                 {
 269                         mbedtls_ssl_config_free(&conf);
 270                 }
 271
 272                 void SetMinDHBits(unsigned int mindh)
 273                 {
 274                         mbedtls_ssl_conf_dhm_min_bitlen(&conf, mindh);
 275                 }
 276
 277                 void SetDHParams(DHParams& dh)
 278                 {
 279                         mbedtls_ssl_conf_dh_param_ctx(&conf, dh.get());
 280                 }
 281
 282                 void SetX509CertAndKey(X509Credentials& x509cred)
 283                 {
 284                         mbedtls_ssl_conf_own_cert(&conf, x509cred.getcerts(), x509cred.getkey());
 285                 }
 286
 287                 void SetCiphersuites(const Ciphersuites& ciphersuites)
 288                 {
 289                         mbedtls_ssl_conf_ciphersuites(&conf, ciphersuites.get());
 290                 }
 291
 292                 void SetCurves(const Curves& curves)
 293                 {
 294                         mbedtls_ssl_conf_curves(&conf, curves.get());
 295                 }
 296
 297                 void SetVersion(int minver, int maxver)
 298                 {
 299                         // SSL v3 support cannot be enabled
 300                         if (minver)
 301                                 mbedtls_ssl_conf_min_version(&conf, MBEDTLS_SSL_MAJOR_VERSION_3, minver);
 302                         if (maxver)
 303                                 mbedtls_ssl_conf_max_version(&conf, MBEDTLS_SSL_MAJOR_VERSION_3, maxver);
 304                 }
 305
 306                 void SetCA(X509CertList& certs, X509CRL& crl)
 307                 {
 308                         mbedtls_ssl_conf_ca_chain(&conf, certs.get(), crl.get());
 309                 }
 310
 311                 const mbedtls_ssl_config* GetConf() const { return &conf; }
 312         };
 313
 314         class Hash
 315         {
 316                 const mbedtls_md_info_t* md;
 317
 318                 /** Buffer where cert hashes are written temporarily
 319                  */
 320                 mutable std::vector<unsigned char> buf;
 321
 322          public:
 323                 Hash(std::string hashstr)
 324                 {
 325                         std::transform(hashstr.begin(), hashstr.end(), hashstr.begin(), ::toupper);
 326                         md = mbedtls_md_info_from_string(hashstr.c_str());
 327                         if (!md)
 328                                 throw Exception("Unknown hash: " + hashstr);
 329
 330                         buf.resize(mbedtls_md_get_size(md));
 331                 }
 332
 333                 std::string hash(const unsigned char* input, size_t length) const
 334                 {
 335                         mbedtls_md(md, input, length, &buf.front());
 336                         return BinToHex(&buf.front(), buf.size());
 337                 }
 338         };
 339
 340         class Profile : public refcountbase
 341         {
 342                 /** Name of this profile
 343                  */
 344                 const std::string name;
 345
 346                 X509Credentials x509cred;
 347
 348                 /** Ciphersuites to use
 349                  */
 350                 Ciphersuites ciphersuites;
 351
 352                 /** Curves accepted for use in ECDHE and in the peer's end-entity certificate
 353                  */
 354                 Curves curves;
 355
 356                 Context serverctx;
 357                 Context clientctx;
 358
 359                 DHParams dhparams;
 360
 361                 X509CertList cacerts;
 362
 363                 X509CRL crl;
 364
 365                 /** Hashing algorithm to use when generating certificate fingerprints
 366                  */
 367                 Hash hash;
 368
 369                 /** Rough max size of records to send
 370                  */
 371                 const unsigned int outrecsize;
 372
 373                 Profile(const std::string& profilename, const std::string& certstr, const std::string& keystr,
 374                                 const std::string& dhstr, unsigned int mindh, const std::string& hashstr,
 375                                 const std::string& ciphersuitestr, const std::string& curvestr,
 376                                 const std::string& castr, const std::string& crlstr,
 377                                 unsigned int recsize,
 378                                 CTRDRBG& ctrdrbg,
 379                                 int minver, int maxver
 380                                 )
 381                         : name(profilename)
 382                         , x509cred(certstr, keystr)
 383                         , ciphersuites(ciphersuitestr)
 384                         , curves(curvestr)
 385                         , serverctx(ctrdrbg, MBEDTLS_SSL_IS_SERVER)
 386                         , clientctx(ctrdrbg, MBEDTLS_SSL_IS_CLIENT)
 387                         , cacerts(castr, true)
 388                         , crl(crlstr)
 389                         , hash(hashstr)
 390                         , outrecsize(recsize)
 391                 {
 392                         serverctx.SetX509CertAndKey(x509cred);
 393                         clientctx.SetX509CertAndKey(x509cred);
 394                         clientctx.SetMinDHBits(mindh);
 395
 396                         if (!ciphersuites.empty())
 397                         {
 398                                 serverctx.SetCiphersuites(ciphersuites);
 399                                 clientctx.SetCiphersuites(ciphersuites);
 400                         }
 401
 402                         if (!curves.empty())
 403                         {
 404                                 serverctx.SetCurves(curves);
 405                                 clientctx.SetCurves(curves);
 406                         }
 407
 408                         serverctx.SetVersion(minver, maxver);
 409                         clientctx.SetVersion(minver, maxver);
 410
 411                         if (!dhstr.empty())
 412                         {
 413                                 dhparams.set(dhstr);
 414                                 serverctx.SetDHParams(dhparams);
 415                         }
 416
 417                         serverctx.SetCA(cacerts, crl);
 418                 }
 419
 420                 static std::string ReadFile(const std::string& filename)
 421                 {
 422                         FileReader reader(filename);
 423                         std::string ret = reader.GetString();
 424                         if (ret.empty())
 425                                 throw Exception("Cannot read file " + filename);
 426                         return ret;
 427                 }
 428
 429          public:
 430                 static reference<Profile> Create(const std::string& profilename, ConfigTag* tag, CTRDRBG& ctr_drbg)
 431                 {
 432                         const std::string certstr = ReadFile(tag->getString("certfile", "cert.pem"));
 433                         const std::string keystr = ReadFile(tag->getString("keyfile", "key.pem"));
 434                         const std::string dhstr = ReadFile(tag->getString("dhfile", "dhparams.pem"));
 435
 436                         const std::string ciphersuitestr = tag->getString("ciphersuites");
 437                         const std::string curvestr = tag->getString("curves");
 438                         unsigned int mindh = tag->getInt("mindhbits", 2048);
 439                         std::string hashstr = tag->getString("hash", "sha256");
 440
 441                         std::string crlstr;
 442                         std::string castr = tag->getString("cafile");
 443                         if (!castr.empty())
 444                         {
 445                                 castr = ReadFile(castr);
 446                                 crlstr = tag->getString("crlfile");
 447                                 if (!crlstr.empty())
 448                                         crlstr = ReadFile(crlstr);
 449                         }
 450
 451                         int minver = tag->getInt("minver");
 452                         int maxver = tag->getInt("maxver");
 453                         unsigned int outrecsize = tag->getInt("outrecsize", 2048, 512, 16384);
 454                         return new Profile(profilename, certstr, keystr, dhstr, mindh, hashstr, ciphersuitestr, curvestr, castr, crlstr, outrecsize, ctr_drbg, minver, maxver);
 455                 }
 456
 457                 /** Set up the given session with the settings in this profile
 458                  */
 459                 void SetupClientSession(mbedtls_ssl_context* sess)
 460                 {
 461                         mbedtls_ssl_setup(sess, clientctx.GetConf());
 462                 }
 463
 464                 void SetupServerSession(mbedtls_ssl_context* sess)
 465                 {
 466                         mbedtls_ssl_setup(sess, serverctx.GetConf());
 467                 }
 468
 469                 const std::string& GetName() const { return name; }
 470                 X509Credentials& GetX509Credentials() { return x509cred; }
 471                 unsigned int GetOutgoingRecordSize() const { return outrecsize; }
 472                 const Hash& GetHash() const { return hash; }
 473         };
 474 }
 475
 476 class mbedTLSIOHook : public SSLIOHook
 477 {
 478         enum Status
 479         {
 480                 ISSL_NONE,
 481                 ISSL_HANDSHAKING,
 482                 ISSL_HANDSHAKEN
 483         };
 484
 485         mbedtls_ssl_context sess;
 486         Status status;
 487         reference<mbedTLS::Profile> profile;
 488
 489         void CloseSession()
 490         {
 491                 if (status == ISSL_NONE)
 492                         return;
 493
 494                 mbedtls_ssl_close_notify(&sess);
 495                 mbedtls_ssl_free(&sess);
 496                 certificate = NULL;
 497                 status = ISSL_NONE;
 498         }
 499
 500         // Returns 1 if handshake succeeded, 0 if it is still in progress, -1 if it failed
 501         int Handshake(StreamSocket* sock)
 502         {
 503                 int ret = mbedtls_ssl_handshake(&sess);
 504                 if (ret == 0)
 505                 {
 506                         // Change the seesion state
 507                         this->status = ISSL_HANDSHAKEN;
 508
 509                         VerifyCertificate();
 510
 511                         // Finish writing, if any left
 512                         SocketEngine::ChangeEventMask(sock, FD_WANT_POLL_READ | FD_WANT_NO_WRITE | FD_ADD_TRIAL_WRITE);
 513
 514                         return 1;
 515                 }
 516
 517                 this->status = ISSL_HANDSHAKING;
 518                 if (ret == MBEDTLS_ERR_SSL_WANT_READ)
 519                 {
 520                         SocketEngine::ChangeEventMask(sock, FD_WANT_POLL_READ | FD_WANT_NO_WRITE);
 521                         return 0;
 522                 }
 523                 else if (ret == MBEDTLS_ERR_SSL_WANT_WRITE)
 524                 {
 525                         SocketEngine::ChangeEventMask(sock, FD_WANT_NO_READ | FD_WANT_SINGLE_WRITE);
 526                         return 0;
 527                 }
 528
 529                 sock->SetError("Handshake Failed - " + mbedTLS::ErrorToString(ret));
 530                 CloseSession();
 531                 return -1;
 532         }
 533
 534         // Returns 1 if application I/O should proceed, 0 if it must wait for the underlying protocol to progress, -1 on fatal error
 535         int PrepareIO(StreamSocket* sock)
 536         {
 537                 if (status == ISSL_HANDSHAKEN)
 538                         return 1;
 539                 else if (status == ISSL_HANDSHAKING)
 540                 {
 541                         // The handshake isn't finished, try to finish it
 542                         return Handshake(sock);
 543                 }
 544
 545                 CloseSession();
 546                 sock->SetError("No SSL session");
 547                 return -1;
 548         }
 549
 550         void VerifyCertificate()
 551         {
 552                 this->certificate = new ssl_cert;
 553                 const mbedtls_x509_crt* const cert = mbedtls_ssl_get_peer_cert(&sess);
 554                 if (!cert)
 555                 {
 556                         certificate->error = "No client certificate sent";
 557                         return;
 558                 }
 559
 560                 // If there is a certificate we can always generate a fingerprint
 561                 certificate->fingerprint = profile->GetHash().hash(cert->raw.p, cert->raw.len);
 562
 563                 // At this point mbedTLS verified the cert already, we just need to check the results
 564                 const uint32_t flags = mbedtls_ssl_get_verify_result(&sess);
 565                 if (flags == 0xFFFFFFFF)
 566                 {
 567                         certificate->error = "Internal error during verification";
 568                         return;
 569                 }
 570
 571                 if (flags == 0)
 572                 {
 573                         // Verification succeeded
 574                         certificate->trusted = true;
 575                 }
 576                 else
 577                 {
 578                         // Verification failed
 579                         certificate->trusted = false;
 580                         if ((flags & MBEDTLS_X509_BADCERT_EXPIRED) || (flags & MBEDTLS_X509_BADCERT_FUTURE))
 581                                 certificate->error = "Not activated, or expired certificate";
 582                 }
 583
 584                 certificate->unknownsigner = (flags & MBEDTLS_X509_BADCERT_NOT_TRUSTED);
 585                 certificate->revoked = (flags & MBEDTLS_X509_BADCERT_REVOKED);
 586                 certificate->invalid = ((flags & MBEDTLS_X509_BADCERT_BAD_KEY) || (flags & MBEDTLS_X509_BADCERT_BAD_MD) || (flags & MBEDTLS_X509_BADCERT_BAD_PK));
 587
 588                 GetDNString(&cert->subject, certificate->dn);
 589                 GetDNString(&cert->issuer, certificate->issuer);
 590         }
 591
 592         static void GetDNString(const mbedtls_x509_name* x509name, std::string& out)
 593         {
 594                 char buf[512];
 595                 const int ret = mbedtls_x509_dn_gets(buf, sizeof(buf), x509name);
 596                 if (ret <= 0)
 597                         return;
 598
 599                 out.assign(buf, ret);
 600         }
 601
 602         static int Pull(void* userptr, unsigned char* buffer, size_t size)
 603         {
 604                 StreamSocket* const sock = reinterpret_cast<StreamSocket*>(userptr);
 605                 if (sock->GetEventMask() & FD_READ_WILL_BLOCK)
 606                         return MBEDTLS_ERR_SSL_WANT_READ;
 607
 608                 const int ret = SocketEngine::Recv(sock, reinterpret_cast<char*>(buffer), size, 0);
 609                 if (ret < (int)size)
 610                 {
 611                         SocketEngine::ChangeEventMask(sock, FD_READ_WILL_BLOCK);
 612                         if ((ret == -1) && (SocketEngine::IgnoreError()))
 613                                 return MBEDTLS_ERR_SSL_WANT_READ;
 614                 }
 615                 return ret;
 616         }
 617
 618         static int Push(void* userptr, const unsigned char* buffer, size_t size)
 619         {
 620                 StreamSocket* const sock = reinterpret_cast<StreamSocket*>(userptr);
 621                 if (sock->GetEventMask() & FD_WRITE_WILL_BLOCK)
 622                         return MBEDTLS_ERR_SSL_WANT_WRITE;
 623
 624                 const int ret = SocketEngine::Send(sock, buffer, size, 0);
 625                 if (ret < (int)size)
 626                 {
 627                         SocketEngine::ChangeEventMask(sock, FD_WRITE_WILL_BLOCK);
 628                         if ((ret == -1) && (SocketEngine::IgnoreError()))
 629                                 return MBEDTLS_ERR_SSL_WANT_WRITE;
 630                 }
 631                 return ret;
 632         }
 633
 634  public:
 635         mbedTLSIOHook(IOHookProvider* hookprov, StreamSocket* sock, bool isserver, mbedTLS::Profile* sslprofile)
 636                 : SSLIOHook(hookprov)
 637                 , status(ISSL_NONE)
 638                 , profile(sslprofile)
 639         {
 640                 mbedtls_ssl_init(&sess);
 641                 if (isserver)
 642                         profile->SetupServerSession(&sess);
 643                 else
 644                         profile->SetupClientSession(&sess);
 645
 646                 mbedtls_ssl_set_bio(&sess, reinterpret_cast<void*>(sock), Push, Pull, NULL);
 647
 648                 sock->AddIOHook(this);
 649                 Handshake(sock);
 650         }
 651
 652         void OnStreamSocketClose(StreamSocket* sock) CXX11_OVERRIDE
 653         {
 654                 CloseSession();
 655         }
 656
 657         int OnStreamSocketRead(StreamSocket* sock, std::string& recvq) CXX11_OVERRIDE
 658         {
 659                 // Finish handshake if needed
 660                 int prepret = PrepareIO(sock);
 661                 if (prepret <= 0)
 662                         return prepret;
 663
 664                 // If we resumed the handshake then this->status will be ISSL_HANDSHAKEN.
 665                 char* const readbuf = ServerInstance->GetReadBuffer();
 666                 const size_t readbufsize = ServerInstance->Config->NetBufferSize;
 667                 int ret = mbedtls_ssl_read(&sess, reinterpret_cast<unsigned char*>(readbuf), readbufsize);
 668                 if (ret > 0)
 669                 {
 670                         recvq.append(readbuf, ret);
 671
 672                         // Schedule a read if there is still data in the mbedTLS buffer
 673                         if (mbedtls_ssl_get_bytes_avail(&sess) > 0)
 674                                 SocketEngine::ChangeEventMask(sock, FD_ADD_TRIAL_READ);
 675                         return 1;
 676                 }
 677                 else if (ret == MBEDTLS_ERR_SSL_WANT_READ)
 678                 {
 679                         SocketEngine::ChangeEventMask(sock, FD_WANT_POLL_READ);
 680                         return 0;
 681                 }
 682                 else if (ret == MBEDTLS_ERR_SSL_WANT_WRITE)
 683                 {
 684                         SocketEngine::ChangeEventMask(sock, FD_WANT_NO_READ | FD_WANT_SINGLE_WRITE);
 685                         return 0;
 686                 }
 687                 else if (ret == 0)
 688                 {
 689                         sock->SetError("Connection closed");
 690                         CloseSession();
 691                         return -1;
 692                 }
 693                 else // error or MBEDTLS_ERR_SSL_CLIENT_RECONNECT which we treat as an error
 694                 {
 695                         sock->SetError(mbedTLS::ErrorToString(ret));
 696                         CloseSession();
 697                         return -1;
 698                 }
 699         }
 700
 701         int OnStreamSocketWrite(StreamSocket* sock) CXX11_OVERRIDE
 702         {
 703                 // Finish handshake if needed
 704                 int prepret = PrepareIO(sock);
 705                 if (prepret <= 0)
 706                         return prepret;
 707
 708                 // Session is ready for transferring application data
 709                 StreamSocket::SendQueue& sendq = sock->GetSendQ();
 710                 while (!sendq.empty())
 711                 {
 712                         FlattenSendQueue(sendq, profile->GetOutgoingRecordSize());
 713                         const StreamSocket::SendQueue::Element& buffer = sendq.front();
 714                         int ret = mbedtls_ssl_write(&sess, reinterpret_cast<const unsigned char*>(buffer.data()), buffer.length());
 715                         if (ret == (int)buffer.length())
 716                         {
 717                                 // Wrote entire record, continue sending
 718                                 sendq.pop_front();
 719                         }
 720                         else if (ret > 0)
 721                         {
 722                                 sendq.erase_front(ret);
 723                                 SocketEngine::ChangeEventMask(sock, FD_WANT_SINGLE_WRITE);
 724                                 return 0;
 725                         }
 726                         else if (ret == 0)
 727                         {
 728                                 sock->SetError("Connection closed");
 729                                 CloseSession();
 730                                 return -1;
 731                         }
 732                         else if (ret == MBEDTLS_ERR_SSL_WANT_WRITE)
 733                         {
 734                                 SocketEngine::ChangeEventMask(sock, FD_WANT_SINGLE_WRITE);
 735                                 return 0;
 736                         }
 737                         else if (ret == MBEDTLS_ERR_SSL_WANT_READ)
 738                         {
 739                                 SocketEngine::ChangeEventMask(sock, FD_WANT_POLL_READ);
 740                                 return 0;
 741                         }
 742                         else
 743                         {
 744                                 sock->SetError(mbedTLS::ErrorToString(ret));
 745                                 CloseSession();
 746                                 return -1;
 747                         }
 748                 }
 749
 750                 SocketEngine::ChangeEventMask(sock, FD_WANT_NO_WRITE);
 751                 return 1;
 752         }
 753
 754         void GetCiphersuite(std::string& out) const CXX11_OVERRIDE
 755         {
 756                 if (!IsHandshakeDone())
 757                         return;
 758                 out.append(mbedtls_ssl_get_version(&sess)).push_back('-');
 759
 760                 // All mbedTLS ciphersuite names currently begin with "TLS-" which provides no useful information so skip it, but be prepared if it changes
 761                 const char* const ciphersuitestr = mbedtls_ssl_get_ciphersuite(&sess);
 762                 const char prefix[] = "TLS-";
 763                 unsigned int skip = sizeof(prefix)-1;
 764                 if (strncmp(ciphersuitestr, prefix, sizeof(prefix)-1))
 765                         skip = 0;
 766                 out.append(ciphersuitestr + skip);
 767         }
 768
 769         bool IsHandshakeDone() const { return (status == ISSL_HANDSHAKEN); }
 770 };
 771
 772 class mbedTLSIOHookProvider : public refcountbase, public IOHookProvider
 773 {
 774         reference<mbedTLS::Profile> profile;
 775
 776  public:
 777         mbedTLSIOHookProvider(Module* mod, mbedTLS::Profile* prof)
 778                 : IOHookProvider(mod, "ssl/" + prof->GetName(), IOHookProvider::IOH_SSL)
 779                 , profile(prof)
 780         {
 781                 ServerInstance->Modules->AddService(*this);
 782         }
 783
 784         ~mbedTLSIOHookProvider()
 785         {
 786                 ServerInstance->Modules->DelService(*this);
 787         }
 788
 789         void OnAccept(StreamSocket* sock, irc::sockets::sockaddrs* client, irc::sockets::sockaddrs* server) CXX11_OVERRIDE
 790         {
 791                 new mbedTLSIOHook(this, sock, true, profile);
 792         }
 793
 794         void OnConnect(StreamSocket* sock) CXX11_OVERRIDE
 795         {
 796                 new mbedTLSIOHook(this, sock, false, profile);
 797         }
 798 };
 799
 800 class ModuleSSLmbedTLS : public Module
 801 {
 802         typedef std::vector<reference<mbedTLSIOHookProvider> > ProfileList;
 803
 804         mbedTLS::Entropy entropy;
 805         mbedTLS::CTRDRBG ctr_drbg;
 806         ProfileList profiles;
 807
 808         void ReadProfiles()
 809         {
 810                 // First, store all profiles in a new, temporary container. If no problems occur, swap the two
 811                 // containers; this way if something goes wrong we can go back and continue using the current profiles,
 812                 // avoiding unpleasant situations where no new SSL connections are possible.
 813                 ProfileList newprofiles;
 814
 815                 ConfigTagList tags = ServerInstance->Config->ConfTags("sslprofile");
 816                 if (tags.first == tags.second)
 817                 {
 818                         // No <sslprofile> tags found, create a profile named "mbedtls" from settings in the <mbedtls> block
 819                         const std::string defname = "mbedtls";
 820                         ConfigTag* tag = ServerInstance->Config->ConfValue(defname);
 821                         ServerInstance->Logs->Log(MODNAME, LOG_DEFAULT, "No <sslprofile> tags found; using settings from the <mbedtls> tag");
 822
 823                         try
 824                         {
 825                                 reference<mbedTLS::Profile> profile(mbedTLS::Profile::Create(defname, tag, ctr_drbg));
 826                                 newprofiles.push_back(new mbedTLSIOHookProvider(this, profile));
 827                         }
 828                         catch (CoreException& ex)
 829                         {
 830                                 throw ModuleException("Error while initializing the default SSL profile - " + ex.GetReason());
 831                         }
 832                 }
 833
 834                 for (ConfigIter i = tags.first; i != tags.second; ++i)
 835                 {
 836                         ConfigTag* tag = i->second;
 837                         if (tag->getString("provider") != "mbedtls")
 838                                 continue;
 839
 840                         std::string name = tag->getString("name");
 841                         if (name.empty())
 842                         {
 843                                 ServerInstance->Logs->Log(MODNAME, LOG_DEFAULT, "Ignoring <sslprofile> tag without name at " + tag->getTagLocation());
 844                                 continue;
 845                         }
 846
 847                         reference<mbedTLS::Profile> profile;
 848                         try
 849                         {
 850                                 profile = mbedTLS::Profile::Create(name, tag, ctr_drbg);
 851                         }
 852                         catch (CoreException& ex)
 853                         {
 854                                 throw ModuleException("Error while initializing SSL profile \"" + name + "\" at " + tag->getTagLocation() + " - " + ex.GetReason());
 855                         }
 856
 857                         newprofiles.push_back(new mbedTLSIOHookProvider(this, profile));
 858                 }
 859
 860                 // New profiles are ok, begin using them
 861                 // Old profiles are deleted when their refcount drops to zero
 862                 profiles.swap(newprofiles);
 863         }
 864
 865  public:
 866         void init() CXX11_OVERRIDE
 867         {
 868                 char verbuf[16]; // Should be at least 9 bytes in size
 869                 mbedtls_version_get_string(verbuf);
 870                 ServerInstance->Logs->Log(MODNAME, LOG_DEFAULT, "mbedTLS lib version %s module was compiled for " MBEDTLS_VERSION_STRING, verbuf);
 871
 872                 if (!ctr_drbg.Seed(entropy))
 873                         throw ModuleException("CTR DRBG seed failed");
 874                 ReadProfiles();
 875         }
 876
 877         void OnModuleRehash(User* user, const std::string &param) CXX11_OVERRIDE
 878         {
 879                 if (param != "ssl")
 880                         return;
 881
 882                 try
 883                 {
 884                         ReadProfiles();
 885                 }
 886                 catch (ModuleException& ex)
 887                 {
 888                         ServerInstance->Logs->Log(MODNAME, LOG_DEFAULT, ex.GetReason() + " Not applying settings.");
 889                 }
 890         }
 891
 892         void OnCleanup(int target_type, void* item) CXX11_OVERRIDE
 893         {
 894                 if (target_type != TYPE_USER)
 895                         return;
 896
 897                 LocalUser* user = IS_LOCAL(static_cast<User*>(item));
 898                 if ((user) && (user->eh.GetIOHook()) && (user->eh.GetIOHook()->prov->creator == this))
 899                 {
 900                         // User is using SSL, they're a local user, and they're using our IOHook.
 901                         // Potentially there could be multiple SSL modules loaded at once on different ports.
 902                         ServerInstance->Users.QuitUser(user, "SSL module unloading");
 903                 }
 904         }
 905
 906         ModResult OnCheckReady(LocalUser* user) CXX11_OVERRIDE
 907         {
 908                 if ((user->eh.GetIOHook()) && (user->eh.GetIOHook()->prov->creator == this))
 909                 {
 910                         mbedTLSIOHook* iohook = static_cast<mbedTLSIOHook*>(user->eh.GetIOHook());
 911                         if (!iohook->IsHandshakeDone())
 912                                 return MOD_RES_DENY;
 913                 }
 914
 915                 return MOD_RES_PASSTHRU;
 916         }
 917
 918         Version GetVersion() CXX11_OVERRIDE
 919         {
 920                 return Version("Provides SSL support via mbedTLS (PolarSSL)", VF_VENDOR);
 921         }
 922 };
 923
 924 MODULE_INIT(ModuleSSLmbedTLS)