citadel/modules/crypto/serv_crypto.c

   1 // Copyright (c) 1987-2022 by the citadel.org team
   2 //
   3 // This program is open source software; you can redistribute it and/or modify
   4 // it under the terms of the GNU General Public License version 3.
   5 //
   6 // This program is distributed in the hope that it will be useful,
   7 // but WITHOUT ANY WARRANTY; without even the implied warranty of
   8 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9 // GNU General Public License for more details.
  10
  11 #include <string.h>
  12 #include <unistd.h>
  13 #include <sys/stat.h>
  14 #include <sys/types.h>
  15 #include "sysdep.h"
  16
  17 #ifdef HAVE_OPENSSL
  18 #include <openssl/ssl.h>
  19 #include <openssl/err.h>
  20 #include <openssl/rand.h>
  21 #endif
  22
  23 #include <time.h>
  24
  25 #ifdef HAVE_PTHREAD_H
  26 #include <pthread.h>
  27 #endif
  28
  29 #ifdef HAVE_SYS_SELECT_H
  30 #include <sys/select.h>
  31 #endif
  32
  33 #include <stdio.h>
  34 #include <libcitadel.h>
  35 #include "server.h"
  36 #include "serv_crypto.h"
  37 #include "sysdep_decls.h"
  38 #include "citadel.h"
  39 #include "config.h"
  40 #include "ctdl_module.h"
  41
  42 #ifdef HAVE_OPENSSL
  43 SSL_CTX *ssl_ctx;                               // SSL context for all sessions
  44
  45
  46 void generate_key(char *keyfilename) {
  47         int ret = 0;
  48         RSA *rsa = NULL;
  49         BIGNUM *bne = NULL;
  50         int bits = 2048;
  51         unsigned long e = RSA_F4;
  52         FILE *fp;
  53
  54         if (access(keyfilename, R_OK) == 0) {   // we already have a key, so don't generate a new one
  55                 return;
  56         }
  57
  58         syslog(LOG_INFO, "crypto: generating RSA key pair");
  59
  60         // generate rsa key
  61         bne = BN_new();
  62         ret = BN_set_word(bne,e);
  63         if (ret != 1) {
  64                 goto free_all;
  65         }
  66
  67         rsa = RSA_new();
  68         ret = RSA_generate_key_ex(rsa, bits, bne, NULL);
  69         if (ret != 1) {
  70                 goto free_all;
  71         }
  72
  73         // write the key file
  74         fp = fopen(keyfilename, "w");
  75         if (fp != NULL) {
  76                 chmod(keyfilename, 0600);
  77                 if (PEM_write_RSAPrivateKey(fp, // the file
  78                                         rsa,    // the key
  79                                         NULL,   // no enc
  80                                         NULL,   // no passphrase
  81                                         0,      // no passphrase
  82                                         NULL,   // no callback
  83                                         NULL    // no callback
  84                 ) != 1) {
  85                         syslog(LOG_ERR, "crypto: cannot write key: %s", ERR_reason_error_string(ERR_get_error()));
  86                         unlink(keyfilename);
  87                 }
  88                 fclose(fp);
  89         }
  90
  91         // free the memory we used
  92 free_all:
  93         RSA_free(rsa);
  94         BN_free(bne);
  95 }
  96
  97
  98 // Set the private key and certificate chain for the global SSL Context.
  99 // This is called during initialization, and can be called again later if the certificate changes.
 100 void bind_to_key_and_certificate(void) {
 101
 102         syslog(LOG_DEBUG, "crypto: using certificate chain %s", file_crpt_file_cer);
 103         SSL_CTX_use_certificate_chain_file(ssl_ctx, file_crpt_file_cer);
 104
 105         syslog(LOG_DEBUG, "crypto: using private key %s", file_crpt_file_key);
 106         SSL_CTX_use_PrivateKey_file(ssl_ctx, file_crpt_file_key, SSL_FILETYPE_PEM);
 107         if ( !SSL_CTX_check_private_key(ssl_ctx) ) {
 108                 syslog(LOG_ERR, "crypto: cannot install certificate: %s", ERR_reason_error_string(ERR_get_error()));
 109         }
 110 }
 111
 112
 113 // Check the modification time of the key and certificate -- reload if they changed
 114 void update_key_and_cert_if_needed(void) {
 115         static time_t previous_mtime = 0;
 116         struct stat keystat;
 117         struct stat certstat;
 118
 119         if (stat(file_crpt_file_key, &keystat) != 0) {
 120                 syslog(LOG_ERR, "%s: %s", file_crpt_file_key, strerror(errno));
 121                 return;
 122         }
 123         if (stat(file_crpt_file_cer, &certstat) != 0) {
 124                 syslog(LOG_ERR, "%s: %s", file_crpt_file_cer, strerror(errno));
 125                 return;
 126         }
 127
 128         if ((keystat.st_mtime + certstat.st_mtime) != previous_mtime) {
 129                 bind_to_key_and_certificate();
 130                 previous_mtime = keystat.st_mtime + certstat.st_mtime;
 131         }
 132 }
 133
 134
 135 void init_ssl(void) {
 136         RSA *rsa = NULL;
 137         X509_REQ *req = NULL;
 138         X509 *cer = NULL;
 139         EVP_PKEY *pk = NULL;
 140         EVP_PKEY *req_pkey = NULL;
 141         X509_NAME *name = NULL;
 142         FILE *fp;
 143
 144         // Initialize SSL transport layer
 145         SSL_library_init();
 146         SSL_load_error_strings();
 147         if (!(ssl_ctx = SSL_CTX_new(SSLv23_server_method()))) {
 148                 syslog(LOG_ERR, "crypto: SSL_CTX_new failed: %s", ERR_reason_error_string(ERR_get_error()));
 149                 return;
 150         }
 151         if (!(SSL_CTX_set_cipher_list(ssl_ctx, CIT_CIPHERS))) {
 152                 syslog(LOG_ERR, "crypto: No ciphers available");
 153                 SSL_CTX_free(ssl_ctx);
 154                 ssl_ctx = NULL;
 155                 return;
 156         }
 157
 158         mkdir(ctdl_key_dir, 0700);              // If the keys directory does not exist, create it
 159         generate_key(file_crpt_file_key);       // If a private key does not exist, create it
 160
 161         // If there is no certificate file on disk, we will be generating a self-signed certificate
 162         // in the next step.  Therefore, if we have neither a CSR nor a certificate, generate
 163         // the CSR in this step so that the next step may commence.
 164         if ( (access(file_crpt_file_cer, R_OK) != 0) && (access(file_crpt_file_csr, R_OK) != 0) ) {
 165                 syslog(LOG_INFO, "crypto: generating a generic certificate signing request.");
 166
 167                 // Read our key from the file.  No, we don't just keep this
 168                 // in memory from the above key-generation function, because
 169                 // there is the possibility that the key was already on disk
 170                 // and we didn't just generate it now.
 171                 fp = fopen(file_crpt_file_key, "r");
 172                 if (fp) {
 173                         rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 174                         fclose(fp);
 175                 }
 176
 177                 if (rsa) {
 178                         // Create a public key from the private key
 179                         if (pk=EVP_PKEY_new(), pk != NULL) {
 180                                 EVP_PKEY_assign_RSA(pk, rsa);
 181                                 if (req = X509_REQ_new(), req != NULL) {
 182
 183                                         // Set the public key
 184                                         X509_REQ_set_pubkey(req, pk);
 185                                         X509_REQ_set_version(req, 0L);
 186
 187                                         name = X509_REQ_get_subject_name(req);
 188
 189                                         // Tell it who we are
 190                                         X509_NAME_add_entry_by_txt(name, "C", MBSTRING_ASC, (unsigned const char *)"ZZ", -1, -1, 0);
 191                                         X509_NAME_add_entry_by_txt(name, "ST", MBSTRING_ASC, (unsigned const char *)"The World", -1, -1, 0);
 192                                         X509_NAME_add_entry_by_txt(name, "L", MBSTRING_ASC, (unsigned const char *)"My Location", -1, -1, 0);
 193                                         X509_NAME_add_entry_by_txt(name, "O", MBSTRING_ASC, (unsigned const char *)"Generic certificate", -1, -1, 0);
 194                                         X509_NAME_add_entry_by_txt(name, "OU", MBSTRING_ASC, (unsigned const char *)"Citadel server", -1, -1, 0);
 195                                         X509_NAME_add_entry_by_txt(name, "CN", MBSTRING_ASC, (unsigned const char *)"*", -1, -1, 0);
 196                                         X509_REQ_set_subject_name(req, name);
 197
 198                                         // Sign the CSR
 199                                         if (!X509_REQ_sign(req, pk, EVP_md5())) {
 200                                                 syslog(LOG_ERR, "crypto: X509_REQ_sign(): error");
 201                                         }
 202                                         else {
 203                                                 // Write it to disk
 204                                                 fp = fopen(file_crpt_file_csr, "w");
 205                                                 if (fp != NULL) {
 206                                                         chmod(file_crpt_file_csr, 0600);
 207                                                         PEM_write_X509_REQ(fp, req);
 208                                                         fclose(fp);
 209                                                 }
 210                                         }
 211
 212                                         X509_REQ_free(req);
 213                                 }
 214                         }
 215                         RSA_free(rsa);
 216                 }
 217                 else {
 218                         syslog(LOG_ERR, "crypto: unable to read private key.");
 219                 }
 220         }
 221
 222         // Generate a self-signed certificate if we don't have one.
 223         if (access(file_crpt_file_cer, R_OK) != 0) {
 224                 syslog(LOG_INFO, "crypto: generating a generic self-signed certificate.");
 225
 226                 // Same deal as before: always read the key from disk because
 227                 // it may or may not have just been generated.
 228                 fp = fopen(file_crpt_file_key, "r");
 229                 if (fp) {
 230                         rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 231                         fclose(fp);
 232                 }
 233
 234                 // This also holds true for the CSR.
 235                 req = NULL;
 236                 cer = NULL;
 237                 pk = NULL;
 238                 if (rsa) {
 239                         if (pk=EVP_PKEY_new(), pk != NULL) {
 240                                 EVP_PKEY_assign_RSA(pk, rsa);
 241                         }
 242
 243                         fp = fopen(file_crpt_file_csr, "r");
 244                         if (fp) {
 245                                 req = PEM_read_X509_REQ(fp, NULL, NULL, NULL);
 246                                 fclose(fp);
 247                         }
 248
 249                         if (req) {
 250                                 if (cer = X509_new(), cer != NULL) {
 251                                         ASN1_INTEGER_set(X509_get_serialNumber(cer), 0);
 252                                         X509_set_issuer_name(cer, X509_REQ_get_subject_name(req));
 253                                         X509_set_subject_name(cer, X509_REQ_get_subject_name(req));
 254                                         X509_gmtime_adj(X509_get_notBefore(cer),0);
 255                                         X509_gmtime_adj(X509_get_notAfter(cer),(long)60*60*24*SIGN_DAYS);
 256                                         req_pkey = X509_REQ_get_pubkey(req);
 257                                         X509_set_pubkey(cer, req_pkey);
 258                                         EVP_PKEY_free(req_pkey);
 259
 260                                         // Sign the cert
 261                                         if (!X509_sign(cer, pk, EVP_md5())) {
 262                                                 syslog(LOG_ERR, "crypto: X509_sign() error");
 263                                         }
 264                                         else {
 265                                                 // Write it to disk.
 266                                                 fp = fopen(file_crpt_file_cer, "w");
 267                                                 if (fp != NULL) {
 268                                                         chmod(file_crpt_file_cer, 0600);
 269                                                         PEM_write_X509(fp, cer);
 270                                                         fclose(fp);
 271                                                 }
 272                                         }
 273                                         X509_free(cer);
 274                                 }
 275                         }
 276
 277                         RSA_free(rsa);
 278                 }
 279         }
 280
 281         // Now try to bind to the key and certificate.
 282         bind_to_key_and_certificate();
 283
 284         // Finally let the server know we're here
 285         CtdlRegisterProtoHook(cmd_stls, "STLS", "Start SSL/TLS session");
 286         CtdlRegisterProtoHook(cmd_gtls, "GTLS", "Get SSL/TLS session status");
 287         CtdlRegisterSessionHook(endtls, EVT_STOP, PRIO_STOP + 10);
 288 }
 289
 290
 291 // client_write_ssl() Send binary data to the client encrypted.
 292 void client_write_ssl(const char *buf, int nbytes) {
 293         int retval;
 294         int nremain;
 295         char junk[1];
 296
 297         nremain = nbytes;
 298
 299         while (nremain > 0) {
 300                 if (SSL_want_write(CC->ssl)) {
 301                         if ((SSL_read(CC->ssl, junk, 0)) < 1) {
 302                                 syslog(LOG_DEBUG, "crypto: SSL_read in client_write: %s", ERR_reason_error_string(ERR_get_error()));
 303                         }
 304                 }
 305                 retval =
 306                     SSL_write(CC->ssl, &buf[nbytes - nremain], nremain);
 307                 if (retval < 1) {
 308                         long errval;
 309
 310                         errval = SSL_get_error(CC->ssl, retval);
 311                         if (errval == SSL_ERROR_WANT_READ ||
 312                             errval == SSL_ERROR_WANT_WRITE) {
 313                                 sleep(1);
 314                                 continue;
 315                         }
 316                         syslog(LOG_DEBUG, "crypto: SSL_write got error %ld, ret %d", errval, retval);
 317                         if (retval == -1) {
 318                                 syslog(LOG_DEBUG, "crypto: errno is %d", errno);
 319                         }
 320                         endtls();
 321                         client_write(&buf[nbytes - nremain], nremain);
 322                         return;
 323                 }
 324                 nremain -= retval;
 325         }
 326 }
 327
 328
 329 // read data from the encrypted layer.
 330 int client_read_sslbuffer(StrBuf *buf, int timeout) {
 331         char sbuf[16384];       // OpenSSL communicates in 16k blocks, so let's speak its native tongue.
 332         int rlen;
 333         char junk[1];
 334         SSL *pssl = CC->ssl;
 335
 336         if (pssl == NULL) return(-1);
 337
 338         while (1) {
 339                 if (SSL_want_read(pssl)) {
 340                         if ((SSL_write(pssl, junk, 0)) < 1) {
 341                                 syslog(LOG_DEBUG, "crypto: SSL_write in client_read");
 342                         }
 343                 }
 344                 rlen = SSL_read(pssl, sbuf, sizeof(sbuf));
 345                 if (rlen < 1) {
 346                         long errval;
 347
 348                         errval = SSL_get_error(pssl, rlen);
 349                         if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
 350                                 sleep(1);
 351                                 continue;
 352                         }
 353                         syslog(LOG_DEBUG, "crypto: SSL_read got error %ld", errval);
 354                         endtls();
 355                         return (-1);
 356                 }
 357                 StrBufAppendBufPlain(buf, sbuf, rlen, 0);
 358                 return rlen;
 359         }
 360         return (0);
 361 }
 362
 363
 364 int client_readline_sslbuffer(StrBuf *Line, StrBuf *IOBuf, const char **Pos, int timeout) {
 365         const char *pos = NULL;
 366         const char *pLF;
 367         int len, rlen;
 368         int nSuccessLess = 0;
 369         const char *pch = NULL;
 370
 371         if ((Line == NULL) || (Pos == NULL) || (IOBuf == NULL)) {
 372                 if (Pos != NULL) {
 373                         *Pos = NULL;
 374                 }
 375                 return -1;
 376         }
 377
 378         pos = *Pos;
 379         if ((StrLength(IOBuf) > 0) && (pos != NULL) && (pos < ChrPtr(IOBuf) + StrLength(IOBuf))) {
 380                 pch = pos;
 381                 pch = strchr(pch, '\n');
 382
 383                 if (pch == NULL) {
 384                         StrBufAppendBufPlain(Line, pos, StrLength(IOBuf) - (pos - ChrPtr(IOBuf)), 0);
 385                         FlushStrBuf(IOBuf);
 386                         *Pos = NULL;
 387                 }
 388                 else {
 389                         int n = 0;
 390                         if ((pch > ChrPtr(IOBuf)) &&
 391                             (*(pch - 1) == '\r')) {
 392                                 n = 1;
 393                         }
 394                         StrBufAppendBufPlain(Line, pos,
 395                                              (pch - pos - n), 0);
 396
 397                         if (StrLength(IOBuf) <= (pch - ChrPtr(IOBuf) + 1)) {
 398                                 FlushStrBuf(IOBuf);
 399                                 *Pos = NULL;
 400                         }
 401                         else
 402                                 *Pos = pch + 1;
 403                         return StrLength(Line);
 404                 }
 405         }
 406
 407         pLF = NULL;
 408         while ((nSuccessLess < timeout) &&
 409                (pLF == NULL) &&
 410                (CC->ssl != NULL)) {
 411
 412                 rlen = client_read_sslbuffer(IOBuf, timeout);
 413                 if (rlen < 1) {
 414                         return -1;
 415                 }
 416                 else if (rlen > 0) {
 417                         pLF = strchr(ChrPtr(IOBuf), '\n');
 418                 }
 419         }
 420         *Pos = NULL;
 421         if (pLF != NULL) {
 422                 pos = ChrPtr(IOBuf);
 423                 len = pLF - pos;
 424                 if (len > 0 && (*(pLF - 1) == '\r') )
 425                         len --;
 426                 StrBufAppendBufPlain(Line, pos, len, 0);
 427                 if (pLF + 1 >= ChrPtr(IOBuf) + StrLength(IOBuf))
 428                 {
 429                         FlushStrBuf(IOBuf);
 430                 }
 431                 else
 432                         *Pos = pLF + 1;
 433                 return StrLength(Line);
 434         }
 435         return -1;
 436 }
 437
 438
 439 int client_read_sslblob(StrBuf *Target, long bytes, int timeout) {
 440         long baselen;
 441         long RemainRead;
 442         int retval = 0;
 443
 444         baselen = StrLength(Target);
 445
 446         if (StrLength(CC->RecvBuf.Buf) > 0) {
 447                 long RemainLen;
 448                 long TotalLen;
 449                 const char *pchs;
 450
 451                 if (CC->RecvBuf.ReadWritePointer == NULL) {
 452                         CC->RecvBuf.ReadWritePointer = ChrPtr(CC->RecvBuf.Buf);
 453                 }
 454                 pchs = ChrPtr(CC->RecvBuf.Buf);
 455                 TotalLen = StrLength(CC->RecvBuf.Buf);
 456                 RemainLen = TotalLen - (pchs - CC->RecvBuf.ReadWritePointer);
 457                 if (RemainLen > bytes) {
 458                         RemainLen = bytes;
 459                 }
 460                 if (RemainLen > 0) {
 461                         StrBufAppendBufPlain(Target, CC->RecvBuf.ReadWritePointer, RemainLen, 0);
 462                         CC->RecvBuf.ReadWritePointer += RemainLen;
 463                 }
 464                 if ((ChrPtr(CC->RecvBuf.Buf) + StrLength(CC->RecvBuf.Buf)) <= CC->RecvBuf.ReadWritePointer) {
 465                         CC->RecvBuf.ReadWritePointer = NULL;
 466                         FlushStrBuf(CC->RecvBuf.Buf);
 467                 }
 468         }
 469
 470         if (StrLength(Target) >= bytes + baselen) {
 471                 return 1;
 472         }
 473
 474         CC->RecvBuf.ReadWritePointer = NULL;
 475
 476         while ((StrLength(Target) < bytes + baselen) && (retval >= 0)) {
 477                 retval = client_read_sslbuffer(CC->RecvBuf.Buf, timeout);
 478                 if (retval >= 0) {
 479                         RemainRead = bytes - (StrLength (Target) - baselen);
 480                         if (RemainRead < StrLength(CC->RecvBuf.Buf)) {
 481                                 StrBufAppendBufPlain(
 482                                         Target,
 483                                         ChrPtr(CC->RecvBuf.Buf),
 484                                         RemainRead, 0);
 485                                 CC->RecvBuf.ReadWritePointer = ChrPtr(CC->RecvBuf.Buf) + RemainRead;
 486                                 break;
 487                         }
 488                         StrBufAppendBuf(Target, CC->RecvBuf.Buf, 0);    // todo: Buf > bytes?
 489                         FlushStrBuf(CC->RecvBuf.Buf);
 490                 }
 491                 else {
 492                         FlushStrBuf(CC->RecvBuf.Buf);
 493                         return -1;
 494
 495                 }
 496         }
 497         return 1;
 498 }
 499
 500
 501 // CtdlStartTLS() starts SSL/TLS encryption for the current session.  It
 502 // must be supplied with pre-generated strings for responses of "ok," "no
 503 // support for TLS," and "error" so that we can use this in any protocol.
 504 void CtdlStartTLS(char *ok_response, char *nosup_response, char *error_response) {
 505         int retval, bits, alg_bits;
 506
 507         if (CC->redirect_ssl) {
 508                 syslog(LOG_ERR, "crypto: attempt to begin SSL on an already encrypted connection");
 509                 if (error_response != NULL) {
 510                         cprintf("%s", error_response);
 511                 }
 512                 return;
 513         }
 514
 515         if (!ssl_ctx) {
 516                 syslog(LOG_ERR, "crypto: SSL failed: context has not been initialized");
 517                 if (nosup_response != NULL) {
 518                         cprintf("%s", nosup_response);
 519                 }
 520                 return;
 521         }
 522
 523         update_key_and_cert_if_needed();                // did someone update the key or cert?  if so, re-bind them
 524
 525         if (!(CC->ssl = SSL_new(ssl_ctx))) {
 526                 syslog(LOG_ERR, "crypto: SSL_new failed: %s", ERR_reason_error_string(ERR_get_error()));
 527                 if (error_response != NULL) {
 528                         cprintf("%s", error_response);
 529                 }
 530                 return;
 531         }
 532         if (!(SSL_set_fd(CC->ssl, CC->client_socket))) {
 533                 syslog(LOG_ERR, "crypto: SSL_set_fd failed: %s", ERR_reason_error_string(ERR_get_error()));
 534                 SSL_free(CC->ssl);
 535                 CC->ssl = NULL;
 536                 if (error_response != NULL) {
 537                         cprintf("%s", error_response);
 538                 }
 539                 return;
 540         }
 541         if (ok_response != NULL) {
 542                 cprintf("%s", ok_response);
 543         }
 544         retval = SSL_accept(CC->ssl);
 545         if (retval < 1) {
 546                 // Can't notify the client of an error here; they will
 547                 // discover the problem at the SSL layer and should
 548                 // revert to unencrypted communications.
 549                 long errval;
 550                 char error_string[128];
 551
 552                 errval = SSL_get_error(CC->ssl, retval);
 553                 syslog(LOG_ERR, "crypto: SSL_accept failed: retval=%d, errval=%ld, err=%s",
 554                         retval,
 555                         errval,
 556                         ERR_error_string(errval, error_string)
 557                 );
 558                 SSL_free(CC->ssl);
 559                 CC->ssl = NULL;
 560                 return;
 561         }
 562         bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl), &alg_bits);
 563         syslog(LOG_INFO, "crypto: SSL/TLS using %s on %s (%d of %d bits)",
 564                 SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
 565                 SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
 566                 bits, alg_bits
 567         );
 568         CC->redirect_ssl = 1;
 569 }
 570
 571
 572 // cmd_stls() starts SSL/TLS encryption for the current session
 573 void cmd_stls(char *params) {
 574         char ok_response[SIZ];
 575         char nosup_response[SIZ];
 576         char error_response[SIZ];
 577
 578         unbuffer_output();
 579
 580         sprintf(ok_response, "%d Begin TLS negotiation now\n", CIT_OK);
 581         sprintf(nosup_response, "%d TLS not supported here\n", ERROR + CMD_NOT_SUPPORTED);
 582         sprintf(error_response, "%d TLS negotiation error\n", ERROR + INTERNAL_ERROR);
 583
 584         CtdlStartTLS(ok_response, nosup_response, error_response);
 585 }
 586
 587
 588 // cmd_gtls() returns status info about the TLS connection
 589 void cmd_gtls(char *params) {
 590         int bits, alg_bits;
 591
 592         if (!CC->ssl || !CC->redirect_ssl) {
 593                 cprintf("%d Session is not encrypted.\n", ERROR);
 594                 return;
 595         }
 596         bits =
 597             SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl),
 598                                 &alg_bits);
 599         cprintf("%d %s|%s|%d|%d\n", CIT_OK,
 600                 SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
 601                 SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
 602                 alg_bits, bits);
 603 }
 604
 605
 606 // endtls() shuts down the TLS connection
 607 //
 608 // WARNING:  This may make your session vulnerable to a known plaintext
 609 // attack in the current implmentation.
 610 void endtls(void) {
 611         if (!CC->ssl) {
 612                 CC->redirect_ssl = 0;
 613                 return;
 614         }
 615
 616         syslog(LOG_INFO, "crypto: ending SSL/TLS");
 617         SSL_shutdown(CC->ssl);
 618         SSL_free(CC->ssl);
 619         CC->ssl = NULL;
 620         CC->redirect_ssl = 0;
 621 }
 622
 623 #endif  // HAVE_OPENSSL