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
  41
  42 #include "ctdl_module.h"
  43
  44 #ifdef HAVE_OPENSSL
  45 SSL_CTX *ssl_ctx;               /* SSL context */
  46 pthread_mutex_t **SSLCritters;  /* Things needing locking */
  47
  48
  49 static unsigned long id_callback(void) {
  50         return (unsigned long) pthread_self();
  51 }
  52
  53
  54 void destruct_ssl(void) {
  55         int a;
  56         for (a = 0; a < CRYPTO_num_locks(); a++)
  57                 free(SSLCritters[a]);
  58         free (SSLCritters);
  59 }
  60
  61
  62 void generate_key(char *keyfilename) {
  63         int ret = 0;
  64         RSA *rsa = NULL;
  65         BIGNUM *bne = NULL;
  66         int bits = 2048;
  67         unsigned long e = RSA_F4;
  68         FILE *fp;
  69
  70         if (access(keyfilename, R_OK) == 0) {
  71                 return;
  72         }
  73
  74         syslog(LOG_INFO, "crypto: generating RSA key pair");
  75
  76         // generate rsa key
  77         bne = BN_new();
  78         ret = BN_set_word(bne,e);
  79         if (ret != 1) {
  80                 goto free_all;
  81         }
  82
  83         rsa = RSA_new();
  84         ret = RSA_generate_key_ex(rsa, bits, bne, NULL);
  85         if (ret != 1) {
  86                 goto free_all;
  87         }
  88
  89         // write the key file
  90         fp = fopen(keyfilename, "w");
  91         if (fp != NULL) {
  92                 chmod(keyfilename, 0600);
  93                 if (PEM_write_RSAPrivateKey(fp, /* the file */
  94                                         rsa,    /* the key */
  95                                         NULL,   /* no enc */
  96                                         NULL,   /* no passphr */
  97                                         0,      /* no passphr */
  98                                         NULL,   /* no callbk */
  99                                         NULL    /* no callbk */
 100                 ) != 1) {
 101                         syslog(LOG_ERR, "crypto: cannot write key: %s", ERR_reason_error_string(ERR_get_error()));
 102                         unlink(keyfilename);
 103                 }
 104                 fclose(fp);
 105         }
 106
 107     // 4. free
 108 free_all:
 109     RSA_free(rsa);
 110     BN_free(bne);
 111 }
 112
 113
 114 void init_ssl(void) {
 115         const SSL_METHOD *ssl_method;
 116         RSA *rsa = NULL;
 117         X509_REQ *req = NULL;
 118         X509 *cer = NULL;
 119         EVP_PKEY *pk = NULL;
 120         EVP_PKEY *req_pkey = NULL;
 121         X509_NAME *name = NULL;
 122         FILE *fp;
 123
 124         SSLCritters = malloc(CRYPTO_num_locks() * sizeof(pthread_mutex_t *));
 125         if (!SSLCritters) {
 126                 syslog(LOG_ERR, "crypto: can't allocate memory!");
 127                 exit(CTDLEXIT_CRYPTO);
 128         }
 129         else {
 130                 int a;
 131
 132                 for (a = 0; a < CRYPTO_num_locks(); a++) {
 133                         SSLCritters[a] = malloc(sizeof(pthread_mutex_t));
 134                         if (!SSLCritters[a]) {
 135                                 syslog(LOG_ERR, "crypto: can't allocate memory!!");
 136                                 exit(CTDLEXIT_CRYPTO);
 137                         }
 138                         pthread_mutex_init(SSLCritters[a], NULL);
 139                 }
 140         }
 141
 142         /*
 143          * Initialize SSL transport layer
 144          */
 145         SSL_library_init();
 146         SSL_load_error_strings();
 147         ssl_method = SSLv23_server_method();
 148         if (!(ssl_ctx = SSL_CTX_new(ssl_method))) {
 149                 syslog(LOG_ERR, "crypto: SSL_CTX_new failed: %s", ERR_reason_error_string(ERR_get_error()));
 150                 return;
 151         }
 152         if (!(SSL_CTX_set_cipher_list(ssl_ctx, CIT_CIPHERS))) {
 153                 syslog(LOG_ERR, "crypto: No ciphers available");
 154                 SSL_CTX_free(ssl_ctx);
 155                 ssl_ctx = NULL;
 156                 return;
 157         }
 158
 159         CRYPTO_set_locking_callback(ssl_lock);
 160         CRYPTO_set_id_callback(id_callback);
 161
 162         mkdir(ctdl_key_dir, 0700);              // If the keys directory does not exist, create it
 163         generate_key(file_crpt_file_key);       // If a private key does not exist, create it
 164
 165         /*
 166          * If there is no certificate file on disk, we will be generating a self-signed certificate
 167          * in the next step.  Therefore, if we have neither a CSR nor a certificate, generate
 168          * the CSR in this step so that the next step may commence.
 169          */
 170         if ( (access(file_crpt_file_cer, R_OK) != 0) && (access(file_crpt_file_csr, R_OK) != 0) ) {
 171                 syslog(LOG_INFO, "crypto: generating a generic certificate signing request.");
 172
 173                 /*
 174                  * Read our key from the file.  No, we don't just keep this
 175                  * in memory from the above key-generation function, because
 176                  * there is the possibility that the key was already on disk
 177                  * and we didn't just generate it now.
 178                  */
 179                 fp = fopen(file_crpt_file_key, "r");
 180                 if (fp) {
 181                         rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 182                         fclose(fp);
 183                 }
 184
 185                 if (rsa) {
 186
 187                         /* Create a public key from the private key */
 188                         if (pk=EVP_PKEY_new(), pk != NULL) {
 189                                 EVP_PKEY_assign_RSA(pk, rsa);
 190                                 if (req = X509_REQ_new(), req != NULL) {
 191
 192                                         /* Set the public key */
 193                                         X509_REQ_set_pubkey(req, pk);
 194                                         X509_REQ_set_version(req, 0L);
 195
 196                                         name = X509_REQ_get_subject_name(req);
 197
 198                                         /* Tell it who we are */
 199                                         X509_NAME_add_entry_by_txt(name, "C", MBSTRING_ASC, (unsigned const char *)"ZZ", -1, -1, 0);
 200                                         X509_NAME_add_entry_by_txt(name, "ST", MBSTRING_ASC, (unsigned const char *)"The World", -1, -1, 0);
 201                                         X509_NAME_add_entry_by_txt(name, "L", MBSTRING_ASC, (unsigned const char *)"My Location", -1, -1, 0);
 202                                         X509_NAME_add_entry_by_txt(name, "O", MBSTRING_ASC, (unsigned const char *)"Generic certificate", -1, -1, 0);
 203                                         X509_NAME_add_entry_by_txt(name, "OU", MBSTRING_ASC, (unsigned const char *)"Citadel server", -1, -1, 0);
 204                                         X509_NAME_add_entry_by_txt(name, "CN", MBSTRING_ASC, (unsigned const char *)"*", -1, -1, 0);
 205                                         X509_REQ_set_subject_name(req, name);
 206
 207                                         /* Sign the CSR */
 208                                         if (!X509_REQ_sign(req, pk, EVP_md5())) {
 209                                                 syslog(LOG_ERR, "crypto: X509_REQ_sign(): error");
 210                                         }
 211                                         else {
 212                                                 /* Write it to disk. */
 213                                                 fp = fopen(file_crpt_file_csr, "w");
 214                                                 if (fp != NULL) {
 215                                                         chmod(file_crpt_file_csr, 0600);
 216                                                         PEM_write_X509_REQ(fp, req);
 217                                                         fclose(fp);
 218                                                 }
 219                                         }
 220
 221                                         X509_REQ_free(req);
 222                                 }
 223                         }
 224
 225                         RSA_free(rsa);
 226                 }
 227
 228                 else {
 229                         syslog(LOG_ERR, "crypto: unable to read private key.");
 230                 }
 231         }
 232
 233
 234         /*
 235          * Generate a self-signed certificate if we don't have one.
 236          */
 237         if (access(file_crpt_file_cer, R_OK) != 0) {
 238                 syslog(LOG_INFO, "crypto: generating a generic self-signed certificate.");
 239
 240                 /* Same deal as before: always read the key from disk because
 241                  * it may or may not have just been generated.
 242                  */
 243                 fp = fopen(file_crpt_file_key, "r");
 244                 if (fp) {
 245                         rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 246                         fclose(fp);
 247                 }
 248
 249                 /* This also holds true for the CSR. */
 250                 req = NULL;
 251                 cer = NULL;
 252                 pk = NULL;
 253                 if (rsa) {
 254                         if (pk=EVP_PKEY_new(), pk != NULL) {
 255                                 EVP_PKEY_assign_RSA(pk, rsa);
 256                         }
 257
 258                         fp = fopen(file_crpt_file_csr, "r");
 259                         if (fp) {
 260                                 req = PEM_read_X509_REQ(fp, NULL, NULL, NULL);
 261                                 fclose(fp);
 262                         }
 263
 264                         if (req) {
 265                                 if (cer = X509_new(), cer != NULL) {
 266                                         ASN1_INTEGER_set(X509_get_serialNumber(cer), 0);
 267                                         X509_set_issuer_name(cer, X509_REQ_get_subject_name(req));
 268                                         X509_set_subject_name(cer, X509_REQ_get_subject_name(req));
 269                                         X509_gmtime_adj(X509_get_notBefore(cer),0);
 270                                         X509_gmtime_adj(X509_get_notAfter(cer),(long)60*60*24*SIGN_DAYS);
 271                                         req_pkey = X509_REQ_get_pubkey(req);
 272                                         X509_set_pubkey(cer, req_pkey);
 273                                         EVP_PKEY_free(req_pkey);
 274
 275                                         /* Sign the cert */
 276                                         if (!X509_sign(cer, pk, EVP_md5())) {
 277                                                 syslog(LOG_ERR, "crypto: X509_sign() error");
 278                                         }
 279                                         else {
 280                                                 /* Write it to disk. */
 281                                                 fp = fopen(file_crpt_file_cer, "w");
 282                                                 if (fp != NULL) {
 283                                                         chmod(file_crpt_file_cer, 0600);
 284                                                         PEM_write_X509(fp, cer);
 285                                                         fclose(fp);
 286                                                 }
 287                                         }
 288                                         X509_free(cer);
 289                                 }
 290                         }
 291
 292                         RSA_free(rsa);
 293                 }
 294         }
 295
 296
 297         /*
 298          * Now try to bind to the key and certificate.
 299          */
 300         SSL_CTX_use_certificate_chain_file(ssl_ctx, file_crpt_file_cer);
 301         SSL_CTX_use_PrivateKey_file(ssl_ctx, file_crpt_file_key, SSL_FILETYPE_PEM);
 302         if ( !SSL_CTX_check_private_key(ssl_ctx) ) {
 303                 syslog(LOG_ERR, "crypto: cannot install certificate: %s", ERR_reason_error_string(ERR_get_error()));
 304         }
 305
 306         /* Finally let the server know we're here */
 307         CtdlRegisterProtoHook(cmd_stls, "STLS", "Start SSL/TLS session");
 308         CtdlRegisterProtoHook(cmd_gtls, "GTLS", "Get SSL/TLS session status");
 309         CtdlRegisterSessionHook(endtls, EVT_STOP, PRIO_STOP + 10);
 310 }
 311
 312
 313 // client_write_ssl() Send binary data to the client encrypted.
 314 void client_write_ssl(const char *buf, int nbytes) {
 315         int retval;
 316         int nremain;
 317         char junk[1];
 318
 319         nremain = nbytes;
 320
 321         while (nremain > 0) {
 322                 if (SSL_want_write(CC->ssl)) {
 323                         if ((SSL_read(CC->ssl, junk, 0)) < 1) {
 324                                 syslog(LOG_DEBUG, "crypto: SSL_read in client_write: %s", ERR_reason_error_string(ERR_get_error()));
 325                         }
 326                 }
 327                 retval =
 328                     SSL_write(CC->ssl, &buf[nbytes - nremain], nremain);
 329                 if (retval < 1) {
 330                         long errval;
 331
 332                         errval = SSL_get_error(CC->ssl, retval);
 333                         if (errval == SSL_ERROR_WANT_READ ||
 334                             errval == SSL_ERROR_WANT_WRITE) {
 335                                 sleep(1);
 336                                 continue;
 337                         }
 338                         syslog(LOG_DEBUG, "crypto: SSL_write got error %ld, ret %d", errval, retval);
 339                         if (retval == -1) {
 340                                 syslog(LOG_DEBUG, "crypto: errno is %d", errno);
 341                         }
 342                         endtls();
 343                         client_write(&buf[nbytes - nremain], nremain);
 344                         return;
 345                 }
 346                 nremain -= retval;
 347         }
 348 }
 349
 350
 351 // read data from the encrypted layer.
 352 int client_read_sslbuffer(StrBuf *buf, int timeout) {
 353         char sbuf[16384]; /* OpenSSL communicates in 16k blocks, so let's speak its native tongue. */
 354         int rlen;
 355         char junk[1];
 356         SSL *pssl = CC->ssl;
 357
 358         if (pssl == NULL) return(-1);
 359
 360         while (1) {
 361                 if (SSL_want_read(pssl)) {
 362                         if ((SSL_write(pssl, junk, 0)) < 1) {
 363                                 syslog(LOG_DEBUG, "crypto: SSL_write in client_read");
 364                         }
 365                 }
 366                 rlen = SSL_read(pssl, sbuf, sizeof(sbuf));
 367                 if (rlen < 1) {
 368                         long errval;
 369
 370                         errval = SSL_get_error(pssl, rlen);
 371                         if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
 372                                 sleep(1);
 373                                 continue;
 374                         }
 375                         syslog(LOG_DEBUG, "crypto: SSL_read got error %ld", errval);
 376                         endtls();
 377                         return (-1);
 378                 }
 379                 StrBufAppendBufPlain(buf, sbuf, rlen, 0);
 380                 return rlen;
 381         }
 382         return (0);
 383 }
 384
 385
 386 int client_readline_sslbuffer(StrBuf *Line, StrBuf *IOBuf, const char **Pos, int timeout) {
 387         const char *pos = NULL;
 388         const char *pLF;
 389         int len, rlen;
 390         int nSuccessLess = 0;
 391         const char *pch = NULL;
 392
 393         if ((Line == NULL) || (Pos == NULL) || (IOBuf == NULL))
 394         {
 395                 if (Pos != NULL)
 396                 {
 397                         *Pos = NULL;
 398                 }
 399                 return -1;
 400         }
 401
 402         pos = *Pos;
 403         if ((StrLength(IOBuf) > 0) && (pos != NULL) && (pos < ChrPtr(IOBuf) + StrLength(IOBuf)))
 404         {
 405                 pch = pos;
 406                 pch = strchr(pch, '\n');
 407
 408                 if (pch == NULL) {
 409                         StrBufAppendBufPlain(Line, pos, StrLength(IOBuf) - (pos - ChrPtr(IOBuf)), 0);
 410                         FlushStrBuf(IOBuf);
 411                         *Pos = NULL;
 412                 }
 413                 else {
 414                         int n = 0;
 415                         if ((pch > ChrPtr(IOBuf)) &&
 416                             (*(pch - 1) == '\r')) {
 417                                 n = 1;
 418                         }
 419                         StrBufAppendBufPlain(Line, pos,
 420                                              (pch - pos - n), 0);
 421
 422                         if (StrLength(IOBuf) <= (pch - ChrPtr(IOBuf) + 1)) {
 423                                 FlushStrBuf(IOBuf);
 424                                 *Pos = NULL;
 425                         }
 426                         else
 427                                 *Pos = pch + 1;
 428                         return StrLength(Line);
 429                 }
 430         }
 431
 432         pLF = NULL;
 433         while ((nSuccessLess < timeout) &&
 434                (pLF == NULL) &&
 435                (CC->ssl != NULL)) {
 436
 437                 rlen = client_read_sslbuffer(IOBuf, timeout);
 438                 if (rlen < 1) {
 439                         return -1;
 440                 }
 441                 else if (rlen > 0) {
 442                         pLF = strchr(ChrPtr(IOBuf), '\n');
 443                 }
 444         }
 445         *Pos = NULL;
 446         if (pLF != NULL) {
 447                 pos = ChrPtr(IOBuf);
 448                 len = pLF - pos;
 449                 if (len > 0 && (*(pLF - 1) == '\r') )
 450                         len --;
 451                 StrBufAppendBufPlain(Line, pos, len, 0);
 452                 if (pLF + 1 >= ChrPtr(IOBuf) + StrLength(IOBuf))
 453                 {
 454                         FlushStrBuf(IOBuf);
 455                 }
 456                 else
 457                         *Pos = pLF + 1;
 458                 return StrLength(Line);
 459         }
 460         return -1;
 461 }
 462
 463
 464 int client_read_sslblob(StrBuf *Target, long bytes, int timeout) {
 465         long baselen;
 466         long RemainRead;
 467         int retval = 0;
 468
 469         baselen = StrLength(Target);
 470
 471         if (StrLength(CC->RecvBuf.Buf) > 0)
 472         {
 473                 long RemainLen;
 474                 long TotalLen;
 475                 const char *pchs;
 476
 477                 if (CC->RecvBuf.ReadWritePointer == NULL)
 478                 {
 479                         CC->RecvBuf.ReadWritePointer = ChrPtr(CC->RecvBuf.Buf);
 480                 }
 481                 pchs = ChrPtr(CC->RecvBuf.Buf);
 482                 TotalLen = StrLength(CC->RecvBuf.Buf);
 483                 RemainLen = TotalLen - (pchs - CC->RecvBuf.ReadWritePointer);
 484                 if (RemainLen > bytes)
 485                 {
 486                         RemainLen = bytes;
 487                 }
 488                 if (RemainLen > 0)
 489                 {
 490                         StrBufAppendBufPlain(Target, CC->RecvBuf.ReadWritePointer, RemainLen, 0);
 491                         CC->RecvBuf.ReadWritePointer += RemainLen;
 492                 }
 493                 if ((ChrPtr(CC->RecvBuf.Buf) + StrLength(CC->RecvBuf.Buf)) <= CC->RecvBuf.ReadWritePointer)
 494                 {
 495                         CC->RecvBuf.ReadWritePointer = NULL;
 496                         FlushStrBuf(CC->RecvBuf.Buf);
 497                 }
 498         }
 499
 500         if (StrLength(Target) >= bytes + baselen) {
 501                 return 1;
 502         }
 503
 504         CC->RecvBuf.ReadWritePointer = NULL;
 505
 506         while ((StrLength(Target) < bytes + baselen) && (retval >= 0)) {
 507                 retval = client_read_sslbuffer(CC->RecvBuf.Buf, timeout);
 508                 if (retval >= 0) {
 509                         RemainRead = bytes - (StrLength (Target) - baselen);
 510                         if (RemainRead < StrLength(CC->RecvBuf.Buf))
 511                         {
 512                                 StrBufAppendBufPlain(
 513                                         Target,
 514                                         ChrPtr(CC->RecvBuf.Buf),
 515                                         RemainRead, 0);
 516                                 CC->RecvBuf.ReadWritePointer = ChrPtr(CC->RecvBuf.Buf) + RemainRead;
 517                                 break;
 518                         }
 519                         StrBufAppendBuf(Target, CC->RecvBuf.Buf, 0); /* todo: Buf > bytes? */
 520                         FlushStrBuf(CC->RecvBuf.Buf);
 521                 }
 522                 else {
 523                         FlushStrBuf(CC->RecvBuf.Buf);
 524                         return -1;
 525
 526                 }
 527         }
 528         return 1;
 529 }
 530
 531
 532 // CtdlStartTLS() starts SSL/TLS encryption for the current session.  It
 533 // must be supplied with pre-generated strings for responses of "ok," "no
 534 // support for TLS," and "error" so that we can use this in any protocol.
 535 void CtdlStartTLS(char *ok_response, char *nosup_response, char *error_response) {
 536         int retval, bits, alg_bits;
 537
 538         if (CC->redirect_ssl) {
 539                 syslog(LOG_ERR, "crypto: attempt to begin SSL on an already encrypted connection");
 540                 if (error_response != NULL) {
 541                         cprintf("%s", error_response);
 542                 }
 543                 return;
 544         }
 545
 546         if (!ssl_ctx) {
 547                 syslog(LOG_ERR, "crypto: SSL failed: no ssl_ctx exists?");
 548                 if (nosup_response != NULL) cprintf("%s", nosup_response);
 549                 return;
 550         }
 551         if (!(CC->ssl = SSL_new(ssl_ctx))) {
 552                 syslog(LOG_ERR, "crypto: SSL_new failed: %s", ERR_reason_error_string(ERR_get_error()));
 553                 if (error_response != NULL) {
 554                         cprintf("%s", error_response);
 555                 }
 556                 return;
 557         }
 558         if (!(SSL_set_fd(CC->ssl, CC->client_socket))) {
 559                 syslog(LOG_ERR, "crypto: SSL_set_fd failed: %s", ERR_reason_error_string(ERR_get_error()));
 560                 SSL_free(CC->ssl);
 561                 CC->ssl = NULL;
 562                 if (error_response != NULL) cprintf("%s", error_response);
 563                 return;
 564         }
 565         if (ok_response != NULL) cprintf("%s", ok_response);
 566         retval = SSL_accept(CC->ssl);
 567         if (retval < 1) {
 568                 /*
 569                  * Can't notify the client of an error here; they will
 570                  * discover the problem at the SSL layer and should
 571                  * revert to unencrypted communications.
 572                  */
 573                 long errval;
 574                 char error_string[128];
 575
 576                 errval = SSL_get_error(CC->ssl, retval);
 577                 syslog(LOG_ERR, "crypto: SSL_accept failed: retval=%d, errval=%ld, err=%s",
 578                         retval,
 579                         errval,
 580                         ERR_error_string(errval, error_string)
 581                 );
 582                 SSL_free(CC->ssl);
 583                 CC->ssl = NULL;
 584                 return;
 585         }
 586         // BIO_set_close(CC->ssl->rbio, BIO_NOCLOSE); not needed anymore in openssl 1.1 ?
 587         bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl), &alg_bits);
 588         syslog(LOG_INFO, "crypto: SSL/TLS using %s on %s (%d of %d bits)",
 589                 SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
 590                 SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
 591                 bits, alg_bits
 592         );
 593         CC->redirect_ssl = 1;
 594 }
 595
 596
 597 // cmd_stls() starts SSL/TLS encryption for the current session
 598 void cmd_stls(char *params) {
 599         char ok_response[SIZ];
 600         char nosup_response[SIZ];
 601         char error_response[SIZ];
 602
 603         unbuffer_output();
 604
 605         sprintf(ok_response, "%d Begin TLS negotiation now\n", CIT_OK);
 606         sprintf(nosup_response, "%d TLS not supported here\n", ERROR + CMD_NOT_SUPPORTED);
 607         sprintf(error_response, "%d TLS negotiation error\n", ERROR + INTERNAL_ERROR);
 608
 609         CtdlStartTLS(ok_response, nosup_response, error_response);
 610 }
 611
 612
 613 // cmd_gtls() returns status info about the TLS connection
 614 void cmd_gtls(char *params) {
 615         int bits, alg_bits;
 616
 617         if (!CC->ssl || !CC->redirect_ssl) {
 618                 cprintf("%d Session is not encrypted.\n", ERROR);
 619                 return;
 620         }
 621         bits =
 622             SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl),
 623                                 &alg_bits);
 624         cprintf("%d %s|%s|%d|%d\n", CIT_OK,
 625                 SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
 626                 SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
 627                 alg_bits, bits);
 628 }
 629
 630
 631 // endtls() shuts down the TLS connection
 632 //
 633 // WARNING:  This may make your session vulnerable to a known plaintext
 634 // attack in the current implmentation.
 635 void endtls(void) {
 636         if (!CC->ssl) {
 637                 CC->redirect_ssl = 0;
 638                 return;
 639         }
 640
 641         syslog(LOG_INFO, "crypto: ending SSL/TLS");
 642         SSL_shutdown(CC->ssl);
 643         SSL_free(CC->ssl);
 644         CC->ssl = NULL;
 645         CC->redirect_ssl = 0;
 646 }
 647
 648
 649 // ssl_lock() callback for OpenSSL mutex locks
 650 void ssl_lock(int mode, int n, const char *file, int line) {
 651         if (mode & CRYPTO_LOCK) {
 652                 pthread_mutex_lock(SSLCritters[n]);
 653         }
 654         else {
 655                 pthread_mutex_unlock(SSLCritters[n]);
 656         }
 657 }
 658 #endif                          /* HAVE_OPENSSL */