citadel/modules/crypto/serv_crypto.c

   1 // Copyright (c) 1987-2021 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 cert_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 > cert_mtime) || (certstat.st_mtime > cert_mtime)) {
 129                 bind_to_key_and_certificate();
 130                 cert_mtime = certstat.st_mtime;
 131         }
 132 }
 133
 134
 135 void init_ssl(void) {
 136         const SSL_METHOD *ssl_method;
 137         RSA *rsa = NULL;
 138         X509_REQ *req = NULL;
 139         X509 *cer = NULL;
 140         EVP_PKEY *pk = NULL;
 141         EVP_PKEY *req_pkey = NULL;
 142         X509_NAME *name = NULL;
 143         FILE *fp;
 144
 145         // Initialize SSL transport layer
 146         SSL_library_init();
 147         SSL_load_error_strings();
 148         ssl_method = SSLv23_server_method();
 149         if (!(ssl_ctx = SSL_CTX_new(ssl_method))) {
 150                 syslog(LOG_ERR, "crypto: SSL_CTX_new failed: %s", ERR_reason_error_string(ERR_get_error()));
 151                 return;
 152         }
 153         if (!(SSL_CTX_set_cipher_list(ssl_ctx, CIT_CIPHERS))) {
 154                 syslog(LOG_ERR, "crypto: No ciphers available");
 155                 SSL_CTX_free(ssl_ctx);
 156                 ssl_ctx = NULL;
 157                 return;
 158         }
 159
 160         mkdir(ctdl_key_dir, 0700);              // If the keys directory does not exist, create it
 161         generate_key(file_crpt_file_key);       // If a private key does not exist, create it
 162
 163         // If there is no certificate file on disk, we will be generating a self-signed certificate
 164         // in the next step.  Therefore, if we have neither a CSR nor a certificate, generate
 165         // the CSR in this step so that the next step may commence.
 166         if ( (access(file_crpt_file_cer, R_OK) != 0) && (access(file_crpt_file_csr, R_OK) != 0) ) {
 167                 syslog(LOG_INFO, "crypto: generating a generic certificate signing request.");
 168
 169                 // Read our key from the file.  No, we don't just keep this
 170                 // in memory from the above key-generation function, because
 171                 // there is the possibility that the key was already on disk
 172                 // and we didn't just generate it now.
 173                 fp = fopen(file_crpt_file_key, "r");
 174                 if (fp) {
 175                         rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 176                         fclose(fp);
 177                 }
 178
 179                 if (rsa) {
 180                         // Create a public key from the private key
 181                         if (pk=EVP_PKEY_new(), pk != NULL) {
 182                                 EVP_PKEY_assign_RSA(pk, rsa);
 183                                 if (req = X509_REQ_new(), req != NULL) {
 184
 185                                         // Set the public key
 186                                         X509_REQ_set_pubkey(req, pk);
 187                                         X509_REQ_set_version(req, 0L);
 188
 189                                         name = X509_REQ_get_subject_name(req);
 190
 191                                         // Tell it who we are
 192                                         X509_NAME_add_entry_by_txt(name, "C", MBSTRING_ASC, (unsigned const char *)"ZZ", -1, -1, 0);
 193                                         X509_NAME_add_entry_by_txt(name, "ST", MBSTRING_ASC, (unsigned const char *)"The World", -1, -1, 0);
 194                                         X509_NAME_add_entry_by_txt(name, "L", MBSTRING_ASC, (unsigned const char *)"My Location", -1, -1, 0);
 195                                         X509_NAME_add_entry_by_txt(name, "O", MBSTRING_ASC, (unsigned const char *)"Generic certificate", -1, -1, 0);
 196                                         X509_NAME_add_entry_by_txt(name, "OU", MBSTRING_ASC, (unsigned const char *)"Citadel server", -1, -1, 0);
 197                                         X509_NAME_add_entry_by_txt(name, "CN", MBSTRING_ASC, (unsigned const char *)"*", -1, -1, 0);
 198                                         X509_REQ_set_subject_name(req, name);
 199
 200                                         // Sign the CSR
 201                                         if (!X509_REQ_sign(req, pk, EVP_md5())) {
 202                                                 syslog(LOG_ERR, "crypto: X509_REQ_sign(): error");
 203                                         }
 204                                         else {
 205                                                 // Write it to disk
 206                                                 fp = fopen(file_crpt_file_csr, "w");
 207                                                 if (fp != NULL) {
 208                                                         chmod(file_crpt_file_csr, 0600);
 209                                                         PEM_write_X509_REQ(fp, req);
 210                                                         fclose(fp);
 211                                                 }
 212                                         }
 213
 214                                         X509_REQ_free(req);
 215                                 }
 216                         }
 217                         RSA_free(rsa);
 218                 }
 219                 else {
 220                         syslog(LOG_ERR, "crypto: unable to read private key.");
 221                 }
 222         }
 223
 224         // Generate a self-signed certificate if we don't have one.
 225         if (access(file_crpt_file_cer, R_OK) != 0) {
 226                 syslog(LOG_INFO, "crypto: generating a generic self-signed certificate.");
 227
 228                 // Same deal as before: always read the key from disk because
 229                 // it may or may not have just been generated.
 230                 fp = fopen(file_crpt_file_key, "r");
 231                 if (fp) {
 232                         rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 233                         fclose(fp);
 234                 }
 235
 236                 // This also holds true for the CSR.
 237                 req = NULL;
 238                 cer = NULL;
 239                 pk = NULL;
 240                 if (rsa) {
 241                         if (pk=EVP_PKEY_new(), pk != NULL) {
 242                                 EVP_PKEY_assign_RSA(pk, rsa);
 243                         }
 244
 245                         fp = fopen(file_crpt_file_csr, "r");
 246                         if (fp) {
 247                                 req = PEM_read_X509_REQ(fp, NULL, NULL, NULL);
 248                                 fclose(fp);
 249                         }
 250
 251                         if (req) {
 252                                 if (cer = X509_new(), cer != NULL) {
 253                                         ASN1_INTEGER_set(X509_get_serialNumber(cer), 0);
 254                                         X509_set_issuer_name(cer, X509_REQ_get_subject_name(req));
 255                                         X509_set_subject_name(cer, X509_REQ_get_subject_name(req));
 256                                         X509_gmtime_adj(X509_get_notBefore(cer),0);
 257                                         X509_gmtime_adj(X509_get_notAfter(cer),(long)60*60*24*SIGN_DAYS);
 258                                         req_pkey = X509_REQ_get_pubkey(req);
 259                                         X509_set_pubkey(cer, req_pkey);
 260                                         EVP_PKEY_free(req_pkey);
 261
 262                                         // Sign the cert
 263                                         if (!X509_sign(cer, pk, EVP_md5())) {
 264                                                 syslog(LOG_ERR, "crypto: X509_sign() error");
 265                                         }
 266                                         else {
 267                                                 // Write it to disk.
 268                                                 fp = fopen(file_crpt_file_cer, "w");
 269                                                 if (fp != NULL) {
 270                                                         chmod(file_crpt_file_cer, 0600);
 271                                                         PEM_write_X509(fp, cer);
 272                                                         fclose(fp);
 273                                                 }
 274                                         }
 275                                         X509_free(cer);
 276                                 }
 277                         }
 278
 279                         RSA_free(rsa);
 280                 }
 281         }
 282
 283         // Now try to bind to the key and certificate.
 284         bind_to_key_and_certificate();
 285
 286         // Finally let the server know we're here
 287         CtdlRegisterProtoHook(cmd_stls, "STLS", "Start SSL/TLS session");
 288         CtdlRegisterProtoHook(cmd_gtls, "GTLS", "Get SSL/TLS session status");
 289         CtdlRegisterSessionHook(endtls, EVT_STOP, PRIO_STOP + 10);
 290 }
 291
 292
 293 // client_write_ssl() Send binary data to the client encrypted.
 294 void client_write_ssl(const char *buf, int nbytes) {
 295         int retval;
 296         int nremain;
 297         char junk[1];
 298
 299         nremain = nbytes;
 300
 301         while (nremain > 0) {
 302                 if (SSL_want_write(CC->ssl)) {
 303                         if ((SSL_read(CC->ssl, junk, 0)) < 1) {
 304                                 syslog(LOG_DEBUG, "crypto: SSL_read in client_write: %s", ERR_reason_error_string(ERR_get_error()));
 305                         }
 306                 }
 307                 retval =
 308                     SSL_write(CC->ssl, &buf[nbytes - nremain], nremain);
 309                 if (retval < 1) {
 310                         long errval;
 311
 312                         errval = SSL_get_error(CC->ssl, retval);
 313                         if (errval == SSL_ERROR_WANT_READ ||
 314                             errval == SSL_ERROR_WANT_WRITE) {
 315                                 sleep(1);
 316                                 continue;
 317                         }
 318                         syslog(LOG_DEBUG, "crypto: SSL_write got error %ld, ret %d", errval, retval);
 319                         if (retval == -1) {
 320                                 syslog(LOG_DEBUG, "crypto: errno is %d", errno);
 321                         }
 322                         endtls();
 323                         client_write(&buf[nbytes - nremain], nremain);
 324                         return;
 325                 }
 326                 nremain -= retval;
 327         }
 328 }
 329
 330
 331 // read data from the encrypted layer.
 332 int client_read_sslbuffer(StrBuf *buf, int timeout) {
 333         char sbuf[16384];       // OpenSSL communicates in 16k blocks, so let's speak its native tongue.
 334         int rlen;
 335         char junk[1];
 336         SSL *pssl = CC->ssl;
 337
 338         if (pssl == NULL) return(-1);
 339
 340         while (1) {
 341                 if (SSL_want_read(pssl)) {
 342                         if ((SSL_write(pssl, junk, 0)) < 1) {
 343                                 syslog(LOG_DEBUG, "crypto: SSL_write in client_read");
 344                         }
 345                 }
 346                 rlen = SSL_read(pssl, sbuf, sizeof(sbuf));
 347                 if (rlen < 1) {
 348                         long errval;
 349
 350                         errval = SSL_get_error(pssl, rlen);
 351                         if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
 352                                 sleep(1);
 353                                 continue;
 354                         }
 355                         syslog(LOG_DEBUG, "crypto: SSL_read got error %ld", errval);
 356                         endtls();
 357                         return (-1);
 358                 }
 359                 StrBufAppendBufPlain(buf, sbuf, rlen, 0);
 360                 return rlen;
 361         }
 362         return (0);
 363 }
 364
 365
 366 int client_readline_sslbuffer(StrBuf *Line, StrBuf *IOBuf, const char **Pos, int timeout) {
 367         const char *pos = NULL;
 368         const char *pLF;
 369         int len, rlen;
 370         int nSuccessLess = 0;
 371         const char *pch = NULL;
 372
 373         if ((Line == NULL) || (Pos == NULL) || (IOBuf == NULL)) {
 374                 if (Pos != NULL) {
 375                         *Pos = NULL;
 376                 }
 377                 return -1;
 378         }
 379
 380         pos = *Pos;
 381         if ((StrLength(IOBuf) > 0) && (pos != NULL) && (pos < ChrPtr(IOBuf) + StrLength(IOBuf))) {
 382                 pch = pos;
 383                 pch = strchr(pch, '\n');
 384
 385                 if (pch == NULL) {
 386                         StrBufAppendBufPlain(Line, pos, StrLength(IOBuf) - (pos - ChrPtr(IOBuf)), 0);
 387                         FlushStrBuf(IOBuf);
 388                         *Pos = NULL;
 389                 }
 390                 else {
 391                         int n = 0;
 392                         if ((pch > ChrPtr(IOBuf)) &&
 393                             (*(pch - 1) == '\r')) {
 394                                 n = 1;
 395                         }
 396                         StrBufAppendBufPlain(Line, pos,
 397                                              (pch - pos - n), 0);
 398
 399                         if (StrLength(IOBuf) <= (pch - ChrPtr(IOBuf) + 1)) {
 400                                 FlushStrBuf(IOBuf);
 401                                 *Pos = NULL;
 402                         }
 403                         else
 404                                 *Pos = pch + 1;
 405                         return StrLength(Line);
 406                 }
 407         }
 408
 409         pLF = NULL;
 410         while ((nSuccessLess < timeout) &&
 411                (pLF == NULL) &&
 412                (CC->ssl != NULL)) {
 413
 414                 rlen = client_read_sslbuffer(IOBuf, timeout);
 415                 if (rlen < 1) {
 416                         return -1;
 417                 }
 418                 else if (rlen > 0) {
 419                         pLF = strchr(ChrPtr(IOBuf), '\n');
 420                 }
 421         }
 422         *Pos = NULL;
 423         if (pLF != NULL) {
 424                 pos = ChrPtr(IOBuf);
 425                 len = pLF - pos;
 426                 if (len > 0 && (*(pLF - 1) == '\r') )
 427                         len --;
 428                 StrBufAppendBufPlain(Line, pos, len, 0);
 429                 if (pLF + 1 >= ChrPtr(IOBuf) + StrLength(IOBuf))
 430                 {
 431                         FlushStrBuf(IOBuf);
 432                 }
 433                 else
 434                         *Pos = pLF + 1;
 435                 return StrLength(Line);
 436         }
 437         return -1;
 438 }
 439
 440
 441 int client_read_sslblob(StrBuf *Target, long bytes, int timeout) {
 442         long baselen;
 443         long RemainRead;
 444         int retval = 0;
 445
 446         baselen = StrLength(Target);
 447
 448         if (StrLength(CC->RecvBuf.Buf) > 0) {
 449                 long RemainLen;
 450                 long TotalLen;
 451                 const char *pchs;
 452
 453                 if (CC->RecvBuf.ReadWritePointer == NULL) {
 454                         CC->RecvBuf.ReadWritePointer = ChrPtr(CC->RecvBuf.Buf);
 455                 }
 456                 pchs = ChrPtr(CC->RecvBuf.Buf);
 457                 TotalLen = StrLength(CC->RecvBuf.Buf);
 458                 RemainLen = TotalLen - (pchs - CC->RecvBuf.ReadWritePointer);
 459                 if (RemainLen > bytes) {
 460                         RemainLen = bytes;
 461                 }
 462                 if (RemainLen > 0) {
 463                         StrBufAppendBufPlain(Target, CC->RecvBuf.ReadWritePointer, RemainLen, 0);
 464                         CC->RecvBuf.ReadWritePointer += RemainLen;
 465                 }
 466                 if ((ChrPtr(CC->RecvBuf.Buf) + StrLength(CC->RecvBuf.Buf)) <= CC->RecvBuf.ReadWritePointer) {
 467                         CC->RecvBuf.ReadWritePointer = NULL;
 468                         FlushStrBuf(CC->RecvBuf.Buf);
 469                 }
 470         }
 471
 472         if (StrLength(Target) >= bytes + baselen) {
 473                 return 1;
 474         }
 475
 476         CC->RecvBuf.ReadWritePointer = NULL;
 477
 478         while ((StrLength(Target) < bytes + baselen) && (retval >= 0)) {
 479                 retval = client_read_sslbuffer(CC->RecvBuf.Buf, timeout);
 480                 if (retval >= 0) {
 481                         RemainRead = bytes - (StrLength (Target) - baselen);
 482                         if (RemainRead < StrLength(CC->RecvBuf.Buf)) {
 483                                 StrBufAppendBufPlain(
 484                                         Target,
 485                                         ChrPtr(CC->RecvBuf.Buf),
 486                                         RemainRead, 0);
 487                                 CC->RecvBuf.ReadWritePointer = ChrPtr(CC->RecvBuf.Buf) + RemainRead;
 488                                 break;
 489                         }
 490                         StrBufAppendBuf(Target, CC->RecvBuf.Buf, 0);    // todo: Buf > bytes?
 491                         FlushStrBuf(CC->RecvBuf.Buf);
 492                 }
 493                 else {
 494                         FlushStrBuf(CC->RecvBuf.Buf);
 495                         return -1;
 496
 497                 }
 498         }
 499         return 1;
 500 }
 501
 502
 503 // CtdlStartTLS() starts SSL/TLS encryption for the current session.  It
 504 // must be supplied with pre-generated strings for responses of "ok," "no
 505 // support for TLS," and "error" so that we can use this in any protocol.
 506 void CtdlStartTLS(char *ok_response, char *nosup_response, char *error_response) {
 507         int retval, bits, alg_bits;
 508
 509         if (CC->redirect_ssl) {
 510                 syslog(LOG_ERR, "crypto: attempt to begin SSL on an already encrypted connection");
 511                 if (error_response != NULL) {
 512                         cprintf("%s", error_response);
 513                 }
 514                 return;
 515         }
 516
 517         if (!ssl_ctx) {
 518                 syslog(LOG_ERR, "crypto: SSL failed: context has not been initialized");
 519                 if (nosup_response != NULL) {
 520                         cprintf("%s", nosup_response);
 521                 }
 522                 return;
 523         }
 524
 525         update_key_and_cert_if_needed();                // did someone update the key or cert?  if so, re-bind them
 526
 527         if (!(CC->ssl = SSL_new(ssl_ctx))) {
 528                 syslog(LOG_ERR, "crypto: SSL_new failed: %s", ERR_reason_error_string(ERR_get_error()));
 529                 if (error_response != NULL) {
 530                         cprintf("%s", error_response);
 531                 }
 532                 return;
 533         }
 534         if (!(SSL_set_fd(CC->ssl, CC->client_socket))) {
 535                 syslog(LOG_ERR, "crypto: SSL_set_fd failed: %s", ERR_reason_error_string(ERR_get_error()));
 536                 SSL_free(CC->ssl);
 537                 CC->ssl = NULL;
 538                 if (error_response != NULL) {
 539                         cprintf("%s", error_response);
 540                 }
 541                 return;
 542         }
 543         if (ok_response != NULL) {
 544                 cprintf("%s", ok_response);
 545         }
 546         retval = SSL_accept(CC->ssl);
 547         if (retval < 1) {
 548                 // Can't notify the client of an error here; they will
 549                 // discover the problem at the SSL layer and should
 550                 // revert to unencrypted communications.
 551                 long errval;
 552                 char error_string[128];
 553
 554                 errval = SSL_get_error(CC->ssl, retval);
 555                 syslog(LOG_ERR, "crypto: SSL_accept failed: retval=%d, errval=%ld, err=%s",
 556                         retval,
 557                         errval,
 558                         ERR_error_string(errval, error_string)
 559                 );
 560                 SSL_free(CC->ssl);
 561                 CC->ssl = NULL;
 562                 return;
 563         }
 564         bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl), &alg_bits);
 565         syslog(LOG_INFO, "crypto: SSL/TLS using %s on %s (%d of %d bits)",
 566                 SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
 567                 SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
 568                 bits, alg_bits
 569         );
 570         CC->redirect_ssl = 1;
 571 }
 572
 573
 574 // cmd_stls() starts SSL/TLS encryption for the current session
 575 void cmd_stls(char *params) {
 576         char ok_response[SIZ];
 577         char nosup_response[SIZ];
 578         char error_response[SIZ];
 579
 580         unbuffer_output();
 581
 582         sprintf(ok_response, "%d Begin TLS negotiation now\n", CIT_OK);
 583         sprintf(nosup_response, "%d TLS not supported here\n", ERROR + CMD_NOT_SUPPORTED);
 584         sprintf(error_response, "%d TLS negotiation error\n", ERROR + INTERNAL_ERROR);
 585
 586         CtdlStartTLS(ok_response, nosup_response, error_response);
 587 }
 588
 589
 590 // cmd_gtls() returns status info about the TLS connection
 591 void cmd_gtls(char *params) {
 592         int bits, alg_bits;
 593
 594         if (!CC->ssl || !CC->redirect_ssl) {
 595                 cprintf("%d Session is not encrypted.\n", ERROR);
 596                 return;
 597         }
 598         bits =
 599             SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl),
 600                                 &alg_bits);
 601         cprintf("%d %s|%s|%d|%d\n", CIT_OK,
 602                 SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
 603                 SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
 604                 alg_bits, bits);
 605 }
 606
 607
 608 // endtls() shuts down the TLS connection
 609 //
 610 // WARNING:  This may make your session vulnerable to a known plaintext
 611 // attack in the current implmentation.
 612 void endtls(void) {
 613         if (!CC->ssl) {
 614                 CC->redirect_ssl = 0;
 615                 return;
 616         }
 617
 618         syslog(LOG_INFO, "crypto: ending SSL/TLS");
 619         SSL_shutdown(CC->ssl);
 620         SSL_free(CC->ssl);
 621         CC->ssl = NULL;
 622         CC->redirect_ssl = 0;
 623 }
 624
 625 #endif  // HAVE_OPENSSL