citadel/modules/crypto/serv_crypto.c

   1 /*
   2  * Copyright (c) 1987-2015 by the citadel.org team
   3  *
   4  * This program is open source software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 3.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  */
  12
  13 #include <string.h>
  14 #include <unistd.h>
  15 #include <sys/stat.h>
  16 #include <sys/types.h>
  17 #include "sysdep.h"
  18
  19 #ifdef HAVE_OPENSSL
  20 #include <openssl/ssl.h>
  21 #include <openssl/err.h>
  22 #include <openssl/rand.h>
  23 #endif
  24
  25 #if TIME_WITH_SYS_TIME
  26 # include <sys/time.h>
  27 # include <time.h>
  28 #else
  29 # if HAVE_SYS_TIME_H
  30 #  include <sys/time.h>
  31 # else
  32 #  include <time.h>
  33 # endif
  34 #endif
  35
  36 #ifdef HAVE_PTHREAD_H
  37 #include <pthread.h>
  38 #endif
  39
  40 #ifdef HAVE_SYS_SELECT_H
  41 #include <sys/select.h>
  42 #endif
  43
  44 #include <stdio.h>
  45 #include <libcitadel.h>
  46 #include "server.h"
  47 #include "serv_crypto.h"
  48 #include "sysdep_decls.h"
  49 #include "citadel.h"
  50 #include "config.h"
  51
  52
  53 #include "ctdl_module.h"
  54 /* TODO: should we use the standard module init stuff to start this? */
  55 /* TODO: should we register an event handler to call destruct_ssl? */
  56
  57 #ifdef HAVE_OPENSSL
  58 SSL_CTX *ssl_ctx;               /* SSL context */
  59 pthread_mutex_t **SSLCritters;  /* Things needing locking */
  60
  61 static unsigned long id_callback(void)
  62 {
  63         return (unsigned long) pthread_self();
  64 }
  65
  66 void destruct_ssl(void)
  67 {
  68         int a;
  69         for (a = 0; a < CRYPTO_num_locks(); a++)
  70                 free(SSLCritters[a]);
  71         free (SSLCritters);
  72 }
  73
  74 void init_ssl(void)
  75 {
  76         const SSL_METHOD *ssl_method;
  77         DH *dh;
  78         RSA *rsa=NULL;
  79         X509_REQ *req = NULL;
  80         X509 *cer = NULL;
  81         EVP_PKEY *pk = NULL;
  82         EVP_PKEY *req_pkey = NULL;
  83         X509_NAME *name = NULL;
  84         FILE *fp;
  85
  86         if (!access(EGD_POOL, F_OK))
  87                 RAND_egd(EGD_POOL);
  88
  89         if (!RAND_status()) {
  90                 syslog(LOG_CRIT,
  91                         "PRNG not adequately seeded, won't do SSL/TLS\n");
  92                 return;
  93         }
  94         SSLCritters =
  95             malloc(CRYPTO_num_locks() * sizeof(pthread_mutex_t *));
  96         if (!SSLCritters) {
  97                 syslog(LOG_EMERG, "citserver: can't allocate memory!!\n");
  98                 /* Nothing's been initialized, just die */
  99                 exit(1);
 100         } else {
 101                 int a;
 102
 103                 for (a = 0; a < CRYPTO_num_locks(); a++) {
 104                         SSLCritters[a] = malloc(sizeof(pthread_mutex_t));
 105                         if (!SSLCritters[a]) {
 106                                 syslog(LOG_EMERG,
 107                                         "citserver: can't allocate memory!!\n");
 108                                 /* Nothing's been initialized, just die */
 109                                 exit(1);
 110                         }
 111                         pthread_mutex_init(SSLCritters[a], NULL);
 112                 }
 113         }
 114
 115         /*
 116          * Initialize SSL transport layer
 117          */
 118         SSL_library_init();
 119         SSL_load_error_strings();
 120         ssl_method = SSLv23_server_method();
 121         if (!(ssl_ctx = SSL_CTX_new(ssl_method))) {
 122                 syslog(LOG_CRIT, "SSL_CTX_new failed: %s\n",
 123                         ERR_reason_error_string(ERR_get_error()));
 124                 return;
 125         }
 126         if (!(SSL_CTX_set_cipher_list(ssl_ctx, CIT_CIPHERS))) {
 127                 syslog(LOG_CRIT, "SSL: No ciphers available\n");
 128                 SSL_CTX_free(ssl_ctx);
 129                 ssl_ctx = NULL;
 130                 return;
 131         }
 132 #if 0
 133 #if SSLEAY_VERSION_NUMBER >= 0x00906000L
 134         SSL_CTX_set_mode(ssl_ctx, SSL_CTX_get_mode(ssl_ctx) |
 135                          SSL_MODE_AUTO_RETRY);
 136 #endif
 137 #endif
 138
 139         CRYPTO_set_locking_callback(ssl_lock);
 140         CRYPTO_set_id_callback(id_callback);
 141
 142         /* Load DH parameters into the context */
 143         dh = DH_new();
 144         if (!dh) {
 145                 syslog(LOG_CRIT, "init_ssl() can't allocate a DH object: %s\n",
 146                         ERR_reason_error_string(ERR_get_error()));
 147                 SSL_CTX_free(ssl_ctx);
 148                 ssl_ctx = NULL;
 149                 return;
 150         }
 151         if (!(BN_hex2bn(&(dh->p), DH_P))) {
 152                 syslog(LOG_CRIT, "init_ssl() can't assign DH_P: %s\n",
 153                         ERR_reason_error_string(ERR_get_error()));
 154                 SSL_CTX_free(ssl_ctx);
 155                 ssl_ctx = NULL;
 156                 return;
 157         }
 158         if (!(BN_hex2bn(&(dh->g), DH_G))) {
 159                 syslog(LOG_CRIT, "init_ssl() can't assign DH_G: %s\n",
 160                         ERR_reason_error_string(ERR_get_error()));
 161                 SSL_CTX_free(ssl_ctx);
 162                 ssl_ctx = NULL;
 163                 return;
 164         }
 165         dh->length = DH_L;
 166         SSL_CTX_set_tmp_dh(ssl_ctx, dh);
 167         DH_free(dh);
 168
 169         /* Get our certificates in order.
 170          * First, create the key/cert directory if it's not there already...
 171          */
 172         mkdir(ctdl_key_dir, 0700);
 173
 174         /*
 175          * Generate a key pair if we don't have one.
 176          */
 177         if (access(file_crpt_file_key, R_OK) != 0) {
 178                 syslog(LOG_INFO, "Generating RSA key pair.\n");
 179                 rsa = RSA_generate_key(1024,    /* modulus size */
 180                                         65537,  /* exponent */
 181                                         NULL,   /* no callback */
 182                                         NULL);  /* no callback */
 183                 if (rsa == NULL) {
 184                         syslog(LOG_CRIT, "Key generation failed: %s\n",
 185                                 ERR_reason_error_string(ERR_get_error()));
 186                 }
 187                 if (rsa != NULL) {
 188                         fp = fopen(file_crpt_file_key, "w");
 189                         if (fp != NULL) {
 190                                 chmod(file_crpt_file_key, 0600);
 191                                 if (PEM_write_RSAPrivateKey(fp, /* the file */
 192                                                         rsa,    /* the key */
 193                                                         NULL,   /* no enc */
 194                                                         NULL,   /* no passphr */
 195                                                         0,      /* no passphr */
 196                                                         NULL,   /* no callbk */
 197                                                         NULL    /* no callbk */
 198                                 ) != 1) {
 199                                         syslog(LOG_CRIT, "Cannot write key: %s\n",
 200                                                 ERR_reason_error_string(ERR_get_error()));
 201                                         unlink(file_crpt_file_key);
 202                                 }
 203                                 fclose(fp);
 204                         }
 205                         RSA_free(rsa);
 206                 }
 207         }
 208
 209         /*
 210          * If there is no certificate file on disk, we will be generating a self-signed certificate
 211          * in the next step.  Therefore, if we have neither a CSR nor a certificate, generate
 212          * the CSR in this step so that the next step may commence.
 213          */
 214         if ( (access(file_crpt_file_cer, R_OK) != 0) && (access(file_crpt_file_csr, R_OK) != 0) ) {
 215                 syslog(LOG_INFO, "Generating a certificate signing request.\n");
 216
 217                 /*
 218                  * Read our key from the file.  No, we don't just keep this
 219                  * in memory from the above key-generation function, because
 220                  * there is the possibility that the key was already on disk
 221                  * and we didn't just generate it now.
 222                  */
 223                 fp = fopen(file_crpt_file_key, "r");
 224                 if (fp) {
 225                         rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 226                         fclose(fp);
 227                 }
 228
 229                 if (rsa) {
 230
 231                         /* Create a public key from the private key */
 232                         if (pk=EVP_PKEY_new(), pk != NULL) {
 233                                 EVP_PKEY_assign_RSA(pk, rsa);
 234                                 if (req = X509_REQ_new(), req != NULL) {
 235
 236                                         /* Set the public key */
 237                                         X509_REQ_set_pubkey(req, pk);
 238                                         X509_REQ_set_version(req, 0L);
 239
 240                                         name = X509_REQ_get_subject_name(req);
 241
 242                                         /* Tell it who we are */
 243
 244                                         /*
 245                                         X509_NAME_add_entry_by_txt(name, "C",
 246                                                 MBSTRING_ASC, "US", -1, -1, 0);
 247
 248                                         X509_NAME_add_entry_by_txt(name, "ST",
 249                                                 MBSTRING_ASC, "New York", -1, -1, 0);
 250
 251                                         X509_NAME_add_entry_by_txt(name, "L",
 252                                                 MBSTRING_ASC, "Mount Kisco", -1, -1, 0);
 253                                         */
 254
 255                                         X509_NAME_add_entry_by_txt(name, "O",
 256                                                                    MBSTRING_ASC,
 257                                                                    (unsigned char*) CtdlGetConfigStr("c_humannode"),
 258                                                                    -1, -1, 0);
 259
 260                                         X509_NAME_add_entry_by_txt(name, "OU",
 261                                                                    MBSTRING_ASC,
 262                                                                    (unsigned const char*)"Citadel server",
 263                                                                    -1, -1, 0);
 264
 265                                         /* X509_NAME_add_entry_by_txt(name, "CN",
 266                                                 MBSTRING_ASC, CtdlGetConfigStr("c_fqdn"), -1, -1, 0);
 267                                         */
 268
 269                                         X509_NAME_add_entry_by_txt(name,
 270                                                                    "CN",
 271                                                                    MBSTRING_ASC,
 272                                                                    (const unsigned char *)"*", -1, -1, 0);
 273
 274                                         X509_REQ_set_subject_name(req, name);
 275
 276                                         /* Sign the CSR */
 277                                         if (!X509_REQ_sign(req, pk, EVP_md5())) {
 278                                                 syslog(LOG_CRIT, "X509_REQ_sign(): error\n");
 279                                         }
 280                                         else {
 281                                                 /* Write it to disk. */
 282                                                 fp = fopen(file_crpt_file_csr, "w");
 283                                                 if (fp != NULL) {
 284                                                         chmod(file_crpt_file_csr, 0600);
 285                                                         PEM_write_X509_REQ(fp, req);
 286                                                         fclose(fp);
 287                                                 }
 288                                         }
 289
 290                                         X509_REQ_free(req);
 291                                 }
 292                         }
 293
 294                         RSA_free(rsa);
 295                 }
 296
 297                 else {
 298                         syslog(LOG_CRIT, "Unable to read private key.\n");
 299                 }
 300         }
 301
 302
 303
 304         /*
 305          * Generate a self-signed certificate if we don't have one.
 306          */
 307         if (access(file_crpt_file_cer, R_OK) != 0) {
 308                 syslog(LOG_INFO, "Generating a self-signed certificate.\n");
 309
 310                 /* Same deal as before: always read the key from disk because
 311                  * it may or may not have just been generated.
 312                  */
 313                 fp = fopen(file_crpt_file_key, "r");
 314                 if (fp) {
 315                         rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 316                         fclose(fp);
 317                 }
 318
 319                 /* This also holds true for the CSR. */
 320                 req = NULL;
 321                 cer = NULL;
 322                 pk = NULL;
 323                 if (rsa) {
 324                         if (pk=EVP_PKEY_new(), pk != NULL) {
 325                                 EVP_PKEY_assign_RSA(pk, rsa);
 326                         }
 327
 328                         fp = fopen(file_crpt_file_csr, "r");
 329                         if (fp) {
 330                                 req = PEM_read_X509_REQ(fp, NULL, NULL, NULL);
 331                                 fclose(fp);
 332                         }
 333
 334                         if (req) {
 335                                 if (cer = X509_new(), cer != NULL) {
 336
 337                                         ASN1_INTEGER_set(X509_get_serialNumber(cer), 0);
 338                                         X509_set_issuer_name(cer, req->req_info->subject);
 339                                         X509_set_subject_name(cer, req->req_info->subject);
 340                                         X509_gmtime_adj(X509_get_notBefore(cer),0);
 341                                         X509_gmtime_adj(X509_get_notAfter(cer),(long)60*60*24*SIGN_DAYS);
 342                                         req_pkey = X509_REQ_get_pubkey(req);
 343                                         X509_set_pubkey(cer, req_pkey);
 344                                         EVP_PKEY_free(req_pkey);
 345
 346                                         /* Sign the cert */
 347                                         if (!X509_sign(cer, pk, EVP_md5())) {
 348                                                 syslog(LOG_CRIT, "X509_sign(): error\n");
 349                                         }
 350                                         else {
 351                                                 /* Write it to disk. */
 352                                                 fp = fopen(file_crpt_file_cer, "w");
 353                                                 if (fp != NULL) {
 354                                                         chmod(file_crpt_file_cer, 0600);
 355                                                         PEM_write_X509(fp, cer);
 356                                                         fclose(fp);
 357                                                 }
 358                                         }
 359                                         X509_free(cer);
 360                                 }
 361                         }
 362
 363                         RSA_free(rsa);
 364                 }
 365         }
 366
 367
 368         /*
 369          * Now try to bind to the key and certificate.
 370          */
 371         SSL_CTX_use_certificate_chain_file(ssl_ctx, file_crpt_file_cer);
 372         SSL_CTX_use_PrivateKey_file(ssl_ctx, file_crpt_file_key, SSL_FILETYPE_PEM);
 373         if ( !SSL_CTX_check_private_key(ssl_ctx) ) {
 374                 syslog(LOG_CRIT, "Cannot install certificate: %s\n",
 375                                 ERR_reason_error_string(ERR_get_error()));
 376         }
 377
 378         /* Finally let the server know we're here */
 379         CtdlRegisterProtoHook(cmd_stls, "STLS", "Start SSL/TLS session");
 380         CtdlRegisterProtoHook(cmd_gtls, "GTLS",
 381                               "Get SSL/TLS session status");
 382         CtdlRegisterSessionHook(endtls, EVT_STOP, PRIO_STOP + 10);
 383 }
 384
 385
 386 /*
 387  * client_write_ssl() Send binary data to the client encrypted.
 388  */
 389 void client_write_ssl(const char *buf, int nbytes)
 390 {
 391         int retval;
 392         int nremain;
 393         char junk[1];
 394
 395         nremain = nbytes;
 396
 397         while (nremain > 0) {
 398                 if (SSL_want_write(CC->ssl)) {
 399                         if ((SSL_read(CC->ssl, junk, 0)) < 1) {
 400                                 syslog(LOG_DEBUG, "SSL_read in client_write: %s\n", ERR_reason_error_string(ERR_get_error()));
 401                         }
 402                 }
 403                 retval =
 404                     SSL_write(CC->ssl, &buf[nbytes - nremain], nremain);
 405                 if (retval < 1) {
 406                         long errval;
 407
 408                         errval = SSL_get_error(CC->ssl, retval);
 409                         if (errval == SSL_ERROR_WANT_READ ||
 410                             errval == SSL_ERROR_WANT_WRITE) {
 411                                 sleep(1);
 412                                 continue;
 413                         }
 414                         syslog(LOG_DEBUG, "SSL_write got error %ld, ret %d\n", errval, retval);
 415                         if (retval == -1)
 416                                 syslog(LOG_DEBUG, "errno is %d\n", errno);
 417                         endtls();
 418                         client_write(&buf[nbytes - nremain], nremain);
 419                         return;
 420                 }
 421                 nremain -= retval;
 422         }
 423 }
 424
 425
 426 /*
 427  * read data from the encrypted layer.
 428  */
 429 int client_read_sslbuffer(StrBuf *buf, int timeout)
 430 {
 431         char sbuf[16384]; /* OpenSSL communicates in 16k blocks, so let's speak its native tongue. */
 432         int rlen;
 433         char junk[1];
 434         SSL *pssl = CC->ssl;
 435
 436         if (pssl == NULL) return(-1);
 437
 438         while (1) {
 439                 if (SSL_want_read(pssl)) {
 440                         if ((SSL_write(pssl, junk, 0)) < 1) {
 441                                 syslog(LOG_DEBUG, "SSL_write in client_read\n");
 442                         }
 443                 }
 444                 rlen = SSL_read(pssl, sbuf, sizeof(sbuf));
 445                 if (rlen < 1) {
 446                         long errval;
 447
 448                         errval = SSL_get_error(pssl, rlen);
 449                         if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
 450                                 sleep(1);
 451                                 continue;
 452                         }
 453                         syslog(LOG_DEBUG, "SSL_read got error %ld\n", errval);
 454                         endtls();
 455                         return (-1);
 456                 }
 457                 StrBufAppendBufPlain(buf, sbuf, rlen, 0);
 458                 return rlen;
 459         }
 460         return (0);
 461 }
 462
 463 int client_readline_sslbuffer(StrBuf *Line, StrBuf *IOBuf, const char **Pos, int timeout)
 464 {
 465         CitContext *CCC = CC;
 466         const char *pos = NULL;
 467         const char *pLF;
 468         int len, rlen;
 469         int nSuccessLess = 0;
 470         const char *pch = NULL;
 471
 472         if ((Line == NULL) ||
 473             (Pos == NULL) ||
 474             (IOBuf == NULL))
 475         {
 476                 if (Pos != NULL)
 477                         *Pos = NULL;
 478 //              *Error = ErrRBLF_PreConditionFailed;
 479                 return -1;
 480         }
 481
 482         pos = *Pos;
 483         if ((StrLength(IOBuf) > 0) &&
 484             (pos != NULL) &&
 485             (pos < ChrPtr(IOBuf) + StrLength(IOBuf)))
 486         {
 487                 pch = pos;
 488                 pch = strchr(pch, '\n');
 489
 490                 if (pch == NULL) {
 491                         StrBufAppendBufPlain(Line, pos,
 492                                              StrLength(IOBuf) - (pos - ChrPtr(IOBuf)), 0);
 493                         FlushStrBuf(IOBuf);
 494                         *Pos = NULL;
 495                 }
 496                 else {
 497                         int n = 0;
 498                         if ((pch > ChrPtr(IOBuf)) &&
 499                             (*(pch - 1) == '\r')) {
 500                                 n = 1;
 501                         }
 502                         StrBufAppendBufPlain(Line, pos,
 503                                              (pch - pos - n), 0);
 504
 505                         if (StrLength(IOBuf) <= (pch - ChrPtr(IOBuf) + 1)) {
 506                                 FlushStrBuf(IOBuf);
 507                                 *Pos = NULL;
 508                         }
 509                         else
 510                                 *Pos = pch + 1;
 511                         return StrLength(Line);
 512                 }
 513         }
 514
 515         pLF = NULL;
 516         while ((nSuccessLess < timeout) &&
 517                (pLF == NULL) &&
 518                (CCC->ssl != NULL)) {
 519
 520                 rlen = client_read_sslbuffer(IOBuf, timeout);
 521                 if (rlen < 1) {
 522 //                      *Error = strerror(errno);
 523 //                      close(*fd);
 524 //                      *fd = -1;
 525                         return -1;
 526                 }
 527                 else if (rlen > 0) {
 528                         pLF = strchr(ChrPtr(IOBuf), '\n');
 529                 }
 530         }
 531         *Pos = NULL;
 532         if (pLF != NULL) {
 533                 pos = ChrPtr(IOBuf);
 534                 len = pLF - pos;
 535                 if (len > 0 && (*(pLF - 1) == '\r') )
 536                         len --;
 537                 StrBufAppendBufPlain(Line, pos, len, 0);
 538                 if (pLF + 1 >= ChrPtr(IOBuf) + StrLength(IOBuf))
 539                 {
 540                         FlushStrBuf(IOBuf);
 541                 }
 542                 else
 543                         *Pos = pLF + 1;
 544                 return StrLength(Line);
 545         }
 546 //      *Error = ErrRBLF_NotEnoughSentFromServer;
 547         return -1;
 548 }
 549
 550
 551
 552 int client_read_sslblob(StrBuf *Target, long bytes, int timeout)
 553 {
 554         long baselen;
 555         long RemainRead;
 556         int retval = 0;
 557         CitContext *CCC = CC;
 558
 559         baselen = StrLength(Target);
 560
 561         if (StrLength(CCC->RecvBuf.Buf) > 0)
 562         {
 563                 long RemainLen;
 564                 long TotalLen;
 565                 const char *pchs;
 566
 567                 if (CCC->RecvBuf.ReadWritePointer == NULL)
 568                         CCC->RecvBuf.ReadWritePointer = ChrPtr(CCC->RecvBuf.Buf);
 569                 pchs = ChrPtr(CCC->RecvBuf.Buf);
 570                 TotalLen = StrLength(CCC->RecvBuf.Buf);
 571                 RemainLen = TotalLen - (pchs - CCC->RecvBuf.ReadWritePointer);
 572                 if (RemainLen > bytes)
 573                         RemainLen = bytes;
 574                 if (RemainLen > 0)
 575                 {
 576                         StrBufAppendBufPlain(Target,
 577                                              CCC->RecvBuf.ReadWritePointer,
 578                                              RemainLen, 0);
 579                         CCC->RecvBuf.ReadWritePointer += RemainLen;
 580                 }
 581                 if ((ChrPtr(CCC->RecvBuf.Buf) + StrLength(CCC->RecvBuf.Buf)) <= CCC->RecvBuf.ReadWritePointer)
 582                 {
 583                         CCC->RecvBuf.ReadWritePointer = NULL;
 584                         FlushStrBuf(CCC->RecvBuf.Buf);
 585                 }
 586         }
 587
 588         if (StrLength(Target) >= bytes + baselen)
 589                 return 1;
 590
 591         CCC->RecvBuf.ReadWritePointer = NULL;
 592
 593         while ((StrLength(Target) < bytes + baselen) &&
 594                (retval >= 0))
 595         {
 596                 retval = client_read_sslbuffer(CCC->RecvBuf.Buf, timeout);
 597                 if (retval >= 0) {
 598                         RemainRead = bytes - (StrLength (Target) - baselen);
 599                         if (RemainRead < StrLength(CCC->RecvBuf.Buf))
 600                         {
 601                                 StrBufAppendBufPlain(
 602                                         Target,
 603                                         ChrPtr(CCC->RecvBuf.Buf),
 604                                         RemainRead, 0);
 605                                 CCC->RecvBuf.ReadWritePointer = ChrPtr(CCC->RecvBuf.Buf) + RemainRead;
 606                                 break;
 607                         }
 608                         StrBufAppendBuf(Target, CCC->RecvBuf.Buf, 0); /* todo: Buf > bytes? */
 609                         FlushStrBuf(CCC->RecvBuf.Buf);
 610                 }
 611                 else
 612                 {
 613                         FlushStrBuf(CCC->RecvBuf.Buf);
 614                         return -1;
 615
 616                 }
 617         }
 618         return 1;
 619 }
 620
 621
 622 /*
 623  * CtdlStartTLS() starts SSL/TLS encryption for the current session.  It
 624  * must be supplied with pre-generated strings for responses of "ok," "no
 625  * support for TLS," and "error" so that we can use this in any protocol.
 626  */
 627 void CtdlStartTLS(char *ok_response, char *nosup_response,
 628                         char *error_response) {
 629
 630         int retval, bits, alg_bits;
 631
 632         if (!ssl_ctx) {
 633                 syslog(LOG_CRIT, "SSL failed: no ssl_ctx exists?\n");
 634                 if (nosup_response != NULL) cprintf("%s", nosup_response);
 635                 return;
 636         }
 637         if (!(CC->ssl = SSL_new(ssl_ctx))) {
 638                 syslog(LOG_CRIT, "SSL_new failed: %s\n",
 639                                 ERR_reason_error_string(ERR_get_error()));
 640                 if (error_response != NULL) cprintf("%s", error_response);
 641                 return;
 642         }
 643         if (!(SSL_set_fd(CC->ssl, CC->client_socket))) {
 644                 syslog(LOG_CRIT, "SSL_set_fd failed: %s\n",
 645                         ERR_reason_error_string(ERR_get_error()));
 646                 SSL_free(CC->ssl);
 647                 CC->ssl = NULL;
 648                 if (error_response != NULL) cprintf("%s", error_response);
 649                 return;
 650         }
 651         if (ok_response != NULL) cprintf("%s", ok_response);
 652         retval = SSL_accept(CC->ssl);
 653         if (retval < 1) {
 654                 /*
 655                  * Can't notify the client of an error here; they will
 656                  * discover the problem at the SSL layer and should
 657                  * revert to unencrypted communications.
 658                  */
 659                 long errval;
 660                 char error_string[128];
 661
 662                 errval = SSL_get_error(CC->ssl, retval);
 663                 syslog(LOG_CRIT, "SSL_accept failed: retval=%d, errval=%ld, err=%s\n",
 664                         retval,
 665                         errval,
 666                         ERR_error_string(errval, error_string)
 667                 );
 668                 SSL_free(CC->ssl);
 669                 CC->ssl = NULL;
 670                 return;
 671         }
 672         BIO_set_close(CC->ssl->rbio, BIO_NOCLOSE);
 673         bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl), &alg_bits);
 674         syslog(LOG_INFO, "SSL/TLS using %s on %s (%d of %d bits)\n",
 675                 SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
 676                 SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
 677                 bits, alg_bits);
 678         CC->redirect_ssl = 1;
 679 }
 680
 681
 682 /*
 683  * cmd_stls() starts SSL/TLS encryption for the current session
 684  */
 685 void cmd_stls(char *params)
 686 {
 687         char ok_response[SIZ];
 688         char nosup_response[SIZ];
 689         char error_response[SIZ];
 690
 691         unbuffer_output();
 692
 693         sprintf(ok_response,
 694                 "%d Begin TLS negotiation now\n",
 695                 CIT_OK);
 696         sprintf(nosup_response,
 697                 "%d TLS not supported here\n",
 698                 ERROR + CMD_NOT_SUPPORTED);
 699         sprintf(error_response,
 700                 "%d TLS negotiation error\n",
 701                 ERROR + INTERNAL_ERROR);
 702
 703         CtdlStartTLS(ok_response, nosup_response, error_response);
 704 }
 705
 706
 707 /*
 708  * cmd_gtls() returns status info about the TLS connection
 709  */
 710 void cmd_gtls(char *params)
 711 {
 712         int bits, alg_bits;
 713
 714         if (!CC->ssl || !CC->redirect_ssl) {
 715                 cprintf("%d Session is not encrypted.\n", ERROR);
 716                 return;
 717         }
 718         bits =
 719             SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl),
 720                                 &alg_bits);
 721         cprintf("%d %s|%s|%d|%d\n", CIT_OK,
 722                 SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
 723                 SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
 724                 alg_bits, bits);
 725 }
 726
 727
 728 /*
 729  * endtls() shuts down the TLS connection
 730  *
 731  * WARNING:  This may make your session vulnerable to a known plaintext
 732  * attack in the current implmentation.
 733  */
 734 void endtls(void)
 735 {
 736         if (!CC->ssl) {
 737                 CC->redirect_ssl = 0;
 738                 return;
 739         }
 740
 741         syslog(LOG_INFO, "Ending SSL/TLS\n");
 742         SSL_shutdown(CC->ssl);
 743         SSL_free(CC->ssl);
 744         CC->ssl = NULL;
 745         CC->redirect_ssl = 0;
 746 }
 747
 748
 749 /*
 750  * ssl_lock() callback for OpenSSL mutex locks
 751  */
 752 void ssl_lock(int mode, int n, const char *file, int line)
 753 {
 754         if (mode & CRYPTO_LOCK)
 755                 pthread_mutex_lock(SSLCritters[n]);
 756         else
 757                 pthread_mutex_unlock(SSLCritters[n]);
 758 }
 759 #endif                          /* HAVE_OPENSSL */