citadel/server/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_defs.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                 syslog(LOG_INFO, "crypto: %s exists and is readable", keyfilename);
  58                 return;
  59         }
  60
  61         syslog(LOG_INFO, "crypto: generating RSA key pair");
  62
  63         // generate rsa key
  64         bne = BN_new();
  65         ret = BN_set_word(bne,e);
  66         if (ret != 1) {
  67                 goto free_all;
  68         }
  69
  70         rsa = RSA_new();
  71         ret = RSA_generate_key_ex(rsa, bits, bne, NULL);
  72         if (ret != 1) {
  73                 goto free_all;
  74         }
  75
  76         // write the key file
  77         fp = fopen(keyfilename, "w");
  78         if (fp != NULL) {
  79                 chmod(keyfilename, 0600);
  80                 if (PEM_write_RSAPrivateKey(fp, // the file
  81                                         rsa,    // the key
  82                                         NULL,   // no enc
  83                                         NULL,   // no passphrase
  84                                         0,      // no passphrase
  85                                         NULL,   // no callback
  86                                         NULL    // no callback
  87                 ) != 1) {
  88                         syslog(LOG_ERR, "crypto: cannot write key: %s", ERR_reason_error_string(ERR_get_error()));
  89                         unlink(keyfilename);
  90                 }
  91                 fclose(fp);
  92         }
  93
  94         // free the memory we used
  95 free_all:
  96         RSA_free(rsa);
  97         BN_free(bne);
  98 }
  99
 100
 101 // If a certificate does not exist, generate a self-signed one now.
 102 void generate_certificate(char *keyfilename, char *certfilename) {
 103         RSA *private_key = NULL;
 104         EVP_PKEY *public_key = NULL;
 105         X509_REQ *certificate_signing_request = NULL;
 106         X509_NAME *name = NULL;
 107         X509 *certificate = NULL;
 108         FILE *fp;
 109
 110         if (access(certfilename, R_OK) == 0) {                  // already have one.
 111                 syslog(LOG_INFO, "crypto: %s exists and is readable", certfilename);
 112                 return;
 113         }
 114
 115         syslog(LOG_INFO, "crypto: generating a self-signed certificate");
 116
 117         // Read in our private key.
 118         fp = fopen(keyfilename, "r");
 119         if (fp) {
 120                 private_key = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 121                 fclose(fp);
 122         }
 123
 124         if (!private_key) {
 125                 syslog(LOG_ERR, "crypto: cannot read the private key");
 126                 return;
 127         }
 128
 129         // Create a public key from the private key
 130         public_key = EVP_PKEY_new();
 131         if (!public_key) {
 132                 syslog(LOG_ERR, "crypto: cannot allocate public key");
 133                 RSA_free(private_key);
 134                 return;
 135         }
 136         EVP_PKEY_assign_RSA(public_key, private_key);
 137
 138         // Create a certificate signing request
 139         certificate_signing_request = X509_REQ_new();
 140         if (!certificate_signing_request) {
 141                 syslog(LOG_ERR, "crypto: cannot allocate certificate signing request");
 142                 RSA_free(private_key);
 143                 EVP_PKEY_free(public_key);
 144                 return;
 145         }
 146
 147         // Assign the public key to the certificate signing request
 148         X509_REQ_set_pubkey(certificate_signing_request, public_key);
 149         X509_REQ_set_version(certificate_signing_request, 0L);
 150
 151         // Tell it who we are
 152         name = X509_REQ_get_subject_name(certificate_signing_request);
 153         X509_NAME_add_entry_by_txt(name, "C", MBSTRING_ASC, (unsigned const char *)"ZZ", -1, -1, 0);
 154         X509_NAME_add_entry_by_txt(name, "ST", MBSTRING_ASC, (unsigned const char *)"The World", -1, -1, 0);
 155         X509_NAME_add_entry_by_txt(name, "L", MBSTRING_ASC, (unsigned const char *)"My Location", -1, -1, 0);
 156         X509_NAME_add_entry_by_txt(name, "O", MBSTRING_ASC, (unsigned const char *)"Generic certificate", -1, -1, 0);
 157         X509_NAME_add_entry_by_txt(name, "OU", MBSTRING_ASC, (unsigned const char *)"Citadel server", -1, -1, 0);
 158         X509_NAME_add_entry_by_txt(name, "CN", MBSTRING_ASC, (unsigned const char *)"*", -1, -1, 0);
 159         X509_REQ_set_subject_name(certificate_signing_request, name);
 160
 161         // Sign the CSR
 162         //if (!X509_REQ_sign(certificate_signing_request, public_key, EVP_md5())) {
 163         if (!X509_REQ_sign(certificate_signing_request, public_key, EVP_md5()) , 0) {
 164                 syslog(LOG_ERR, "crypto: X509_REQ_sign(): error");
 165                 X509_REQ_free(certificate_signing_request);
 166                 RSA_free(private_key);
 167                 EVP_PKEY_free(public_key);
 168                 return;
 169         }
 170
 171         // Generate the self-signed certificate
 172         certificate = X509_new();
 173         if (!certificate) {
 174                 syslog(LOG_ERR, "crypto: cannot allocate X.509 certificate");
 175                 X509_REQ_free(certificate_signing_request);
 176                 RSA_free(private_key);
 177                 EVP_PKEY_free(public_key);
 178                 return;
 179         }
 180
 181         ASN1_INTEGER_set(X509_get_serialNumber(certificate), 0);
 182         X509_set_issuer_name(certificate, X509_REQ_get_subject_name(certificate_signing_request));
 183         X509_set_subject_name(certificate, X509_REQ_get_subject_name(certificate_signing_request));
 184         X509_gmtime_adj(X509_get_notBefore(certificate), 0);
 185         X509_gmtime_adj(X509_get_notAfter(certificate), (long)60*60*24*SIGN_DAYS);
 186         X509_set_pubkey(certificate, public_key);
 187         X509_REQ_free(certificate_signing_request);             // We're done with the CSR; free it
 188
 189         // Finally, sign the certificate with our private key.
 190         if (!X509_sign(certificate, public_key, EVP_md5())) {
 191                 syslog(LOG_ERR, "crypto: X509_sign() error");
 192                 X509_free(certificate);
 193                 RSA_free(private_key);
 194                 EVP_PKEY_free(public_key);
 195                 return;
 196         }
 197
 198         // Write the certificate to disk
 199         fp = fopen(certfilename, "w");
 200         if (fp != NULL) {
 201                 chmod(certfilename, 0600);
 202                 PEM_write_X509(fp, certificate);
 203                 fclose(fp);
 204         }
 205         else {
 206                 syslog(LOG_ERR, "crypto: %s: %m", certfilename);
 207         }
 208
 209         X509_free(certificate);
 210         EVP_PKEY_free(public_key);
 211         // do not RSA_free(private_key); because it was freed by EVP_PKEY_free() above
 212 }
 213
 214
 215 // Set the private key and certificate chain for the global SSL Context.
 216 // This is called during initialization, and can be called again later if the certificate changes.
 217 void bind_to_key_and_certificate(void) {
 218
 219         SSL_CTX *old_ctx = NULL;
 220         SSL_CTX *new_ctx = NULL;
 221
 222         const SSL_METHOD *method = SSLv23_server_method();
 223         if (!method) {
 224                 syslog(LOG_ERR, "crypto: SSLv23_server_method() failed: %s", ERR_reason_error_string(ERR_get_error()));
 225                 return;
 226         }
 227
 228         new_ctx = SSL_CTX_new(method);
 229         if (!new_ctx) {
 230                 syslog(LOG_ERR, "crypto: SSL_CTX_new failed: %s", ERR_reason_error_string(ERR_get_error()));
 231                 return;
 232         }
 233
 234         if (!(SSL_CTX_set_cipher_list(new_ctx, ssl_cipher_list))) {
 235                 syslog(LOG_ERR, "crypto: SSL_CTX_set_cipher_list failed: %s", ERR_reason_error_string(ERR_get_error()));
 236                 return;
 237         }
 238
 239         syslog(LOG_DEBUG, "crypto: using certificate chain %s", file_crpt_file_cer);
 240         if (!SSL_CTX_use_certificate_chain_file(new_ctx, file_crpt_file_cer)) {
 241                 syslog(LOG_ERR, "crypto: SSL_CTX_use_certificate_chain_file failed: %s", ERR_reason_error_string(ERR_get_error()));
 242                 return;
 243         }
 244
 245         syslog(LOG_DEBUG, "crypto: using private key %s", file_crpt_file_key);
 246         if (!SSL_CTX_use_PrivateKey_file(new_ctx, file_crpt_file_key, SSL_FILETYPE_PEM)) {
 247                 syslog(LOG_ERR, "crypto: SSL_CTX_use_PrivateKey_file failed: %s", ERR_reason_error_string(ERR_get_error()));
 248                 return;
 249         }
 250
 251         old_ctx = ssl_ctx;
 252         ssl_ctx = new_ctx;              // All future binds will use the new certificate
 253
 254         if (old_ctx != NULL) {
 255                 sleep(1);               // Hopefully wait until all in-progress binds to the old certificate have completed
 256                 SSL_CTX_free(old_ctx);
 257         }
 258 }
 259
 260
 261 // Check the modification time of the key and certificate files.  Reload if either one changed.
 262 void update_key_and_cert_if_needed(void) {
 263         static time_t previous_mtime = 0;
 264         struct stat keystat;
 265         struct stat certstat;
 266
 267         if (stat(file_crpt_file_key, &keystat) != 0) {
 268                 syslog(LOG_ERR, "%s: %s", file_crpt_file_key, strerror(errno));
 269                 return;
 270         }
 271         if (stat(file_crpt_file_cer, &certstat) != 0) {
 272                 syslog(LOG_ERR, "%s: %s", file_crpt_file_cer, strerror(errno));
 273                 return;
 274         }
 275
 276         if ((keystat.st_mtime + certstat.st_mtime) != previous_mtime) {
 277                 begin_critical_section(S_OPENSSL);
 278                 bind_to_key_and_certificate();
 279                 end_critical_section(S_OPENSSL);
 280                 previous_mtime = keystat.st_mtime + certstat.st_mtime;
 281         }
 282 }
 283
 284
 285 // Initialize the TLS subsystem.
 286 void init_ssl(void) {
 287
 288         // Initialize the OpenSSL library
 289         SSL_library_init();
 290         SSL_load_error_strings();
 291
 292         // Load (or generate) a key and certificate
 293         mkdir(ctdl_key_dir, 0700);                                      // If the keys directory does not exist, create it
 294         generate_key(file_crpt_file_key);                               // If a private key does not exist, create it
 295         generate_certificate(file_crpt_file_key, file_crpt_file_cer);   // If a certificate does not exist, create it
 296         bind_to_key_and_certificate();                                  // Load key and cert from disk, and bind to them.
 297
 298         // Register some Citadel protocol commands for dealing with encrypted sessions
 299         CtdlRegisterProtoHook(cmd_stls, "STLS", "Start TLS session");
 300         CtdlRegisterProtoHook(cmd_gtls, "GTLS", "Get TLS session status");
 301         CtdlRegisterSessionHook(endtls, EVT_STOP, PRIO_STOP + 10);
 302 }
 303
 304
 305 // client_write_ssl() Send binary data to the client encrypted.
 306 void client_write_ssl(const char *buf, int nbytes) {
 307         int retval;
 308         int nremain;
 309         char junk[1];
 310
 311         nremain = nbytes;
 312
 313         while (nremain > 0) {
 314                 if (SSL_want_write(CC->ssl)) {
 315                         if ((SSL_read(CC->ssl, junk, 0)) < 1) {
 316                                 syslog(LOG_DEBUG, "crypto: SSL_read in client_write: %s", ERR_reason_error_string(ERR_get_error()));
 317                         }
 318                 }
 319                 retval =
 320                     SSL_write(CC->ssl, &buf[nbytes - nremain], nremain);
 321                 if (retval < 1) {
 322                         long errval;
 323
 324                         errval = SSL_get_error(CC->ssl, retval);
 325                         if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
 326                                 sleep(1);
 327                                 continue;
 328                         }
 329                         syslog(LOG_DEBUG, "crypto: SSL_write got error %ld, ret %d", errval, retval);
 330                         if (retval == -1) {
 331                                 syslog(LOG_DEBUG, "crypto: errno is %d", errno);
 332                         }
 333                         endtls();
 334                         client_write(&buf[nbytes - nremain], nremain);
 335                         return;
 336                 }
 337                 nremain -= retval;
 338         }
 339 }
 340
 341
 342 // read data from the encrypted layer.
 343 int client_read_sslbuffer(StrBuf *buf, int timeout) {
 344         char sbuf[16384];       // OpenSSL communicates in 16k blocks, so let's speak its native tongue.
 345         int rlen;
 346         char junk[1];
 347         SSL *pssl = CC->ssl;
 348
 349         if (pssl == NULL) return(-1);
 350
 351         while (1) {
 352                 if (SSL_want_read(pssl)) {
 353                         if ((SSL_write(pssl, junk, 0)) < 1) {
 354                                 syslog(LOG_DEBUG, "crypto: SSL_write in client_read");
 355                         }
 356                 }
 357                 rlen = SSL_read(pssl, sbuf, sizeof(sbuf));
 358                 if (rlen < 1) {
 359                         long errval;
 360
 361                         errval = SSL_get_error(pssl, rlen);
 362                         if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
 363                                 sleep(1);
 364                                 continue;
 365                         }
 366                         syslog(LOG_DEBUG, "crypto: SSL_read got error %ld", errval);
 367                         endtls();
 368                         return (-1);
 369                 }
 370                 StrBufAppendBufPlain(buf, sbuf, rlen, 0);
 371                 return rlen;
 372         }
 373         return (0);
 374 }
 375
 376
 377 int client_readline_sslbuffer(StrBuf *Line, StrBuf *IOBuf, const char **Pos, int timeout) {
 378         const char *pos = NULL;
 379         const char *pLF;
 380         int len, rlen;
 381         int nSuccessLess = 0;
 382         const char *pch = NULL;
 383
 384         if ((Line == NULL) || (Pos == NULL) || (IOBuf == NULL)) {
 385                 if (Pos != NULL) {
 386                         *Pos = NULL;
 387                 }
 388                 return -1;
 389         }
 390
 391         pos = *Pos;
 392         if ((StrLength(IOBuf) > 0) && (pos != NULL) && (pos < ChrPtr(IOBuf) + StrLength(IOBuf))) {
 393                 pch = pos;
 394                 pch = strchr(pch, '\n');
 395
 396                 if (pch == NULL) {
 397                         StrBufAppendBufPlain(Line, pos, StrLength(IOBuf) - (pos - ChrPtr(IOBuf)), 0);
 398                         FlushStrBuf(IOBuf);
 399                         *Pos = NULL;
 400                 }
 401                 else {
 402                         int n = 0;
 403                         if ((pch > ChrPtr(IOBuf)) && (*(pch - 1) == '\r')) {
 404                                 n = 1;
 405                         }
 406                         StrBufAppendBufPlain(Line, pos, (pch - pos - n), 0);
 407
 408                         if (StrLength(IOBuf) <= (pch - ChrPtr(IOBuf) + 1)) {
 409                                 FlushStrBuf(IOBuf);
 410                                 *Pos = NULL;
 411                         }
 412                         else {
 413                                 *Pos = pch + 1;
 414                         }
 415                         return StrLength(Line);
 416                 }
 417         }
 418
 419         pLF = NULL;
 420         while ((nSuccessLess < timeout) && (pLF == NULL) && (CC->ssl != NULL)) {
 421
 422                 rlen = client_read_sslbuffer(IOBuf, timeout);
 423                 if (rlen < 1) {
 424                         return -1;
 425                 }
 426                 else if (rlen > 0) {
 427                         pLF = strchr(ChrPtr(IOBuf), '\n');
 428                 }
 429         }
 430         *Pos = NULL;
 431         if (pLF != NULL) {
 432                 pos = ChrPtr(IOBuf);
 433                 len = pLF - pos;
 434                 if (len > 0 && (*(pLF - 1) == '\r') )
 435                         len --;
 436                 StrBufAppendBufPlain(Line, pos, len, 0);
 437                 if (pLF + 1 >= ChrPtr(IOBuf) + StrLength(IOBuf)) {
 438                         FlushStrBuf(IOBuf);
 439                 }
 440                 else  {
 441                         *Pos = pLF + 1;
 442                 }
 443                 return StrLength(Line);
 444         }
 445         return -1;
 446 }
 447
 448
 449 int client_read_sslblob(StrBuf *Target, long bytes, int timeout) {
 450         long baselen;
 451         long RemainRead;
 452         int retval = 0;
 453
 454         baselen = StrLength(Target);
 455
 456         if (StrLength(CC->RecvBuf.Buf) > 0) {
 457                 long RemainLen;
 458                 long TotalLen;
 459                 const char *pchs;
 460
 461                 if (CC->RecvBuf.ReadWritePointer == NULL) {
 462                         CC->RecvBuf.ReadWritePointer = ChrPtr(CC->RecvBuf.Buf);
 463                 }
 464                 pchs = ChrPtr(CC->RecvBuf.Buf);
 465                 TotalLen = StrLength(CC->RecvBuf.Buf);
 466                 RemainLen = TotalLen - (pchs - CC->RecvBuf.ReadWritePointer);
 467                 if (RemainLen > bytes) {
 468                         RemainLen = bytes;
 469                 }
 470                 if (RemainLen > 0) {
 471                         StrBufAppendBufPlain(Target, CC->RecvBuf.ReadWritePointer, RemainLen, 0);
 472                         CC->RecvBuf.ReadWritePointer += RemainLen;
 473                 }
 474                 if ((ChrPtr(CC->RecvBuf.Buf) + StrLength(CC->RecvBuf.Buf)) <= CC->RecvBuf.ReadWritePointer) {
 475                         CC->RecvBuf.ReadWritePointer = NULL;
 476                         FlushStrBuf(CC->RecvBuf.Buf);
 477                 }
 478         }
 479
 480         if (StrLength(Target) >= bytes + baselen) {
 481                 return 1;
 482         }
 483
 484         CC->RecvBuf.ReadWritePointer = NULL;
 485
 486         while ((StrLength(Target) < bytes + baselen) && (retval >= 0)) {
 487                 retval = client_read_sslbuffer(CC->RecvBuf.Buf, timeout);
 488                 if (retval >= 0) {
 489                         RemainRead = bytes - (StrLength (Target) - baselen);
 490                         if (RemainRead < StrLength(CC->RecvBuf.Buf)) {
 491                                 StrBufAppendBufPlain(
 492                                         Target,
 493                                         ChrPtr(CC->RecvBuf.Buf),
 494                                         RemainRead, 0);
 495                                 CC->RecvBuf.ReadWritePointer = ChrPtr(CC->RecvBuf.Buf) + RemainRead;
 496                                 break;
 497                         }
 498                         StrBufAppendBuf(Target, CC->RecvBuf.Buf, 0);
 499                         FlushStrBuf(CC->RecvBuf.Buf);
 500                 }
 501                 else {
 502                         FlushStrBuf(CC->RecvBuf.Buf);
 503                         return -1;
 504
 505                 }
 506         }
 507         return 1;
 508 }
 509
 510
 511 // CtdlStartTLS() starts TLS encryption for the current session.  It
 512 // must be supplied with pre-generated strings for responses of "ok," "no
 513 // support for TLS," and "error" so that we can use this in any protocol.
 514 void CtdlStartTLS(char *ok_response, char *nosup_response, char *error_response) {
 515         int retval, bits, alg_bits;
 516
 517         if (CC->redirect_ssl) {
 518                 syslog(LOG_ERR, "crypto: attempt to begin SSL on an already encrypted connection");
 519                 if (error_response != NULL) {
 520                         cprintf("%s", error_response);
 521                 }
 522                 return;
 523         }
 524
 525         if (!ssl_ctx) {
 526                 syslog(LOG_ERR, "crypto: SSL failed: ../../context.has not been initialized");
 527                 if (nosup_response != NULL) {
 528                         cprintf("%s", nosup_response);
 529                 }
 530                 return;
 531         }
 532
 533         update_key_and_cert_if_needed();                // did someone update the key or cert?  if so, re-bind them
 534
 535         if (!(CC->ssl = SSL_new(ssl_ctx))) {
 536                 syslog(LOG_ERR, "crypto: SSL_new failed: %s", ERR_reason_error_string(ERR_get_error()));
 537                 if (error_response != NULL) {
 538                         cprintf("%s", error_response);
 539                 }
 540                 return;
 541         }
 542         if (!(SSL_set_fd(CC->ssl, CC->client_socket))) {
 543                 syslog(LOG_ERR, "crypto: SSL_set_fd failed: %s", ERR_reason_error_string(ERR_get_error()));
 544                 SSL_free(CC->ssl);
 545                 CC->ssl = NULL;
 546                 if (error_response != NULL) {
 547                         cprintf("%s", error_response);
 548                 }
 549                 return;
 550         }
 551         if (ok_response != NULL) {
 552                 cprintf("%s", ok_response);
 553         }
 554         retval = SSL_accept(CC->ssl);
 555         if (retval < 1) {
 556                 // Can't notify the client of an error here; they will
 557                 // discover the problem at the SSL layer and should
 558                 // revert to unencrypted communications.
 559                 syslog(LOG_ERR, "crypto: SSL_accept failed: %s", ERR_reason_error_string(ERR_get_error()));
 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: 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 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 = SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl), &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 void endtls(void) {
 608         if (!CC->ssl) {
 609                 CC->redirect_ssl = 0;
 610                 return;
 611         }
 612
 613         syslog(LOG_INFO, "crypto: ending TLS on this session");
 614         SSL_shutdown(CC->ssl);
 615         SSL_free(CC->ssl);
 616         CC->ssl = NULL;
 617         CC->redirect_ssl = 0;
 618 }
 619
 620 #endif  // HAVE_OPENSSL