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