citadel/modules/crypto/serv_crypto.c

   1 /*
   2  * Copyright (c) 1987-2018 by the citadel.org team
   3  *
   4  * This program is open source software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 3.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  */
  12
  13 #include <string.h>
  14 #include <unistd.h>
  15 #include <sys/stat.h>
  16 #include <sys/types.h>
  17 #include "sysdep.h"
  18
  19 #ifdef HAVE_OPENSSL
  20 #include <openssl/ssl.h>
  21 #include <openssl/err.h>
  22 #include <openssl/rand.h>
  23 #endif
  24
  25 #if TIME_WITH_SYS_TIME
  26 # include <sys/time.h>
  27 # include <time.h>
  28 #else
  29 # if HAVE_SYS_TIME_H
  30 #  include <sys/time.h>
  31 # else
  32 #  include <time.h>
  33 # endif
  34 #endif
  35
  36 #ifdef HAVE_PTHREAD_H
  37 #include <pthread.h>
  38 #endif
  39
  40 #ifdef HAVE_SYS_SELECT_H
  41 #include <sys/select.h>
  42 #endif
  43
  44 #include <stdio.h>
  45 #include <libcitadel.h>
  46 #include "server.h"
  47 #include "serv_crypto.h"
  48 #include "sysdep_decls.h"
  49 #include "citadel.h"
  50 #include "config.h"
  51
  52
  53 #include "ctdl_module.h"
  54
  55 #ifdef HAVE_OPENSSL
  56 SSL_CTX *ssl_ctx;               /* SSL context */
  57 pthread_mutex_t **SSLCritters;  /* Things needing locking */
  58
  59 static unsigned long id_callback(void)
  60 {
  61         return (unsigned long) pthread_self();
  62 }
  63
  64 void destruct_ssl(void)
  65 {
  66         int a;
  67         for (a = 0; a < CRYPTO_num_locks(); a++)
  68                 free(SSLCritters[a]);
  69         free (SSLCritters);
  70 }
  71
  72
  73 void generate_key(char *keyfilename)
  74 {
  75         int ret = 0;
  76         RSA *rsa = NULL;
  77         BIGNUM *bne = NULL;
  78         int bits = 2048;
  79         unsigned long e = RSA_F4;
  80         FILE *fp;
  81
  82         if (access(file_crpt_file_key, R_OK) == 0) {
  83                 return;
  84         }
  85
  86         syslog(LOG_INFO, "crypto: generating RSA key pair");
  87
  88         // generate rsa key
  89         bne = BN_new();
  90         ret = BN_set_word(bne,e);
  91         if (ret != 1) {
  92                 goto free_all;
  93         }
  94
  95         rsa = RSA_new();
  96         ret = RSA_generate_key_ex(rsa, bits, bne, NULL);
  97         if (ret != 1) {
  98                 goto free_all;
  99         }
 100
 101         // write the key file
 102         fp = fopen(keyfilename, "w");
 103         if (fp != NULL) {
 104                 chmod(file_crpt_file_key, 0600);
 105                 if (PEM_write_RSAPrivateKey(fp, /* the file */
 106                                         rsa,    /* the key */
 107                                         NULL,   /* no enc */
 108                                         NULL,   /* no passphr */
 109                                         0,      /* no passphr */
 110                                         NULL,   /* no callbk */
 111                                         NULL    /* no callbk */
 112                 ) != 1) {
 113                         syslog(LOG_ERR, "crypto: cannot write key: %s", ERR_reason_error_string(ERR_get_error()));
 114                         unlink(file_crpt_file_key);
 115                 }
 116                 fclose(fp);
 117         }
 118
 119     // 4. free
 120 free_all:
 121     RSA_free(rsa);
 122     BN_free(bne);
 123 }
 124
 125
 126
 127
 128 void init_ssl(void)
 129 {
 130         const SSL_METHOD *ssl_method;
 131         RSA *rsa = NULL;
 132         X509_REQ *req = NULL;
 133         X509 *cer = NULL;
 134         EVP_PKEY *pk = NULL;
 135         EVP_PKEY *req_pkey = NULL;
 136         X509_NAME *name = NULL;
 137         FILE *fp;
 138
 139         SSLCritters = malloc(CRYPTO_num_locks() * sizeof(pthread_mutex_t *));
 140         if (!SSLCritters) {
 141                 syslog(LOG_ERR, "crypto: can't allocate memory!");
 142                 exit(CTDLEXIT_CRYPTO);
 143         } else {
 144                 int a;
 145
 146                 for (a = 0; a < CRYPTO_num_locks(); a++) {
 147                         SSLCritters[a] = malloc(sizeof(pthread_mutex_t));
 148                         if (!SSLCritters[a]) {
 149                                 syslog(LOG_ERR, "crypto: can't allocate memory!!");
 150                                 exit(CTDLEXIT_CRYPTO);
 151                         }
 152                         pthread_mutex_init(SSLCritters[a], NULL);
 153                 }
 154         }
 155
 156         /*
 157          * Initialize SSL transport layer
 158          */
 159         SSL_library_init();
 160         SSL_load_error_strings();
 161         ssl_method = SSLv23_server_method();
 162         if (!(ssl_ctx = SSL_CTX_new(ssl_method))) {
 163                 syslog(LOG_ERR, "crypto: SSL_CTX_new failed: %s", ERR_reason_error_string(ERR_get_error()));
 164                 return;
 165         }
 166         if (!(SSL_CTX_set_cipher_list(ssl_ctx, CIT_CIPHERS))) {
 167                 syslog(LOG_ERR, "crypto: No ciphers available");
 168                 SSL_CTX_free(ssl_ctx);
 169                 ssl_ctx = NULL;
 170                 return;
 171         }
 172
 173         CRYPTO_set_locking_callback(ssl_lock);
 174         CRYPTO_set_id_callback(id_callback);
 175
 176         mkdir(ctdl_key_dir, 0700);              // If the keys directory does not exist, create it
 177         generate_key(file_crpt_file_key);       // If a private key does not exist, create it
 178
 179         /*
 180          * If there is no certificate file on disk, we will be generating a self-signed certificate
 181          * in the next step.  Therefore, if we have neither a CSR nor a certificate, generate
 182          * the CSR in this step so that the next step may commence.
 183          */
 184         if ( (access(file_crpt_file_cer, R_OK) != 0) && (access(file_crpt_file_csr, R_OK) != 0) ) {
 185                 syslog(LOG_INFO, "crypto: generating a generic certificate signing request.");
 186
 187                 /*
 188                  * Read our key from the file.  No, we don't just keep this
 189                  * in memory from the above key-generation function, because
 190                  * there is the possibility that the key was already on disk
 191                  * and we didn't just generate it now.
 192                  */
 193                 fp = fopen(file_crpt_file_key, "r");
 194                 if (fp) {
 195                         rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 196                         fclose(fp);
 197                 }
 198
 199                 if (rsa) {
 200
 201                         /* Create a public key from the private key */
 202                         if (pk=EVP_PKEY_new(), pk != NULL) {
 203                                 EVP_PKEY_assign_RSA(pk, rsa);
 204                                 if (req = X509_REQ_new(), req != NULL) {
 205
 206                                         /* Set the public key */
 207                                         X509_REQ_set_pubkey(req, pk);
 208                                         X509_REQ_set_version(req, 0L);
 209
 210                                         name = X509_REQ_get_subject_name(req);
 211
 212                                         /* Tell it who we are */
 213                                         X509_NAME_add_entry_by_txt(name, "C", MBSTRING_ASC, (unsigned const char *)"ZZ", -1, -1, 0);
 214                                         X509_NAME_add_entry_by_txt(name, "ST", MBSTRING_ASC, (unsigned const char *)"The World", -1, -1, 0);
 215                                         X509_NAME_add_entry_by_txt(name, "L", MBSTRING_ASC, (unsigned const char *)"My Location", -1, -1, 0);
 216                                         X509_NAME_add_entry_by_txt(name, "O", MBSTRING_ASC, (unsigned const char *)"Generic certificate", -1, -1, 0);
 217                                         X509_NAME_add_entry_by_txt(name, "OU", MBSTRING_ASC, (unsigned const char *)"Citadel server", -1, -1, 0);
 218                                         X509_NAME_add_entry_by_txt(name, "CN", MBSTRING_ASC, (unsigned const char *)"*", -1, -1, 0);
 219                                         X509_REQ_set_subject_name(req, name);
 220
 221                                         /* Sign the CSR */
 222                                         if (!X509_REQ_sign(req, pk, EVP_md5())) {
 223                                                 syslog(LOG_ERR, "crypto: X509_REQ_sign(): error");
 224                                         }
 225                                         else {
 226                                                 /* Write it to disk. */
 227                                                 fp = fopen(file_crpt_file_csr, "w");
 228                                                 if (fp != NULL) {
 229                                                         chmod(file_crpt_file_csr, 0600);
 230                                                         PEM_write_X509_REQ(fp, req);
 231                                                         fclose(fp);
 232                                                 }
 233                                         }
 234
 235                                         X509_REQ_free(req);
 236                                 }
 237                         }
 238
 239                         RSA_free(rsa);
 240                 }
 241
 242                 else {
 243                         syslog(LOG_ERR, "crypto: unable to read private key.");
 244                 }
 245         }
 246
 247
 248         /*
 249          * Generate a self-signed certificate if we don't have one.
 250          */
 251         if (access(file_crpt_file_cer, R_OK) != 0) {
 252                 syslog(LOG_INFO, "crypto: generating a generic self-signed certificate.");
 253
 254                 /* Same deal as before: always read the key from disk because
 255                  * it may or may not have just been generated.
 256                  */
 257                 fp = fopen(file_crpt_file_key, "r");
 258                 if (fp) {
 259                         rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 260                         fclose(fp);
 261                 }
 262
 263                 /* This also holds true for the CSR. */
 264                 req = NULL;
 265                 cer = NULL;
 266                 pk = NULL;
 267                 if (rsa) {
 268                         if (pk=EVP_PKEY_new(), pk != NULL) {
 269                                 EVP_PKEY_assign_RSA(pk, rsa);
 270                         }
 271
 272                         fp = fopen(file_crpt_file_csr, "r");
 273                         if (fp) {
 274                                 req = PEM_read_X509_REQ(fp, NULL, NULL, NULL);
 275                                 fclose(fp);
 276                         }
 277
 278                         if (req) {
 279                                 if (cer = X509_new(), cer != NULL) {
 280                                         ASN1_INTEGER_set(X509_get_serialNumber(cer), 0);
 281                                         X509_set_issuer_name(cer, X509_REQ_get_subject_name(req));
 282                                         X509_set_subject_name(cer, X509_REQ_get_subject_name(req));
 283                                         X509_gmtime_adj(X509_get_notBefore(cer),0);
 284                                         X509_gmtime_adj(X509_get_notAfter(cer),(long)60*60*24*SIGN_DAYS);
 285                                         req_pkey = X509_REQ_get_pubkey(req);
 286                                         X509_set_pubkey(cer, req_pkey);
 287                                         EVP_PKEY_free(req_pkey);
 288
 289                                         /* Sign the cert */
 290                                         if (!X509_sign(cer, pk, EVP_md5())) {
 291                                                 syslog(LOG_ERR, "crypto: X509_sign() error");
 292                                         }
 293                                         else {
 294                                                 /* Write it to disk. */
 295                                                 fp = fopen(file_crpt_file_cer, "w");
 296                                                 if (fp != NULL) {
 297                                                         chmod(file_crpt_file_cer, 0600);
 298                                                         PEM_write_X509(fp, cer);
 299                                                         fclose(fp);
 300                                                 }
 301                                         }
 302                                         X509_free(cer);
 303                                 }
 304                         }
 305
 306                         RSA_free(rsa);
 307                 }
 308         }
 309
 310
 311         /*
 312          * Now try to bind to the key and certificate.
 313          */
 314         SSL_CTX_use_certificate_chain_file(ssl_ctx, file_crpt_file_cer);
 315         SSL_CTX_use_PrivateKey_file(ssl_ctx, file_crpt_file_key, SSL_FILETYPE_PEM);
 316         if ( !SSL_CTX_check_private_key(ssl_ctx) ) {
 317                 syslog(LOG_ERR, "crypto: cannot install certificate: %s", ERR_reason_error_string(ERR_get_error()));
 318         }
 319
 320         /* Finally let the server know we're here */
 321         CtdlRegisterProtoHook(cmd_stls, "STLS", "Start SSL/TLS session");
 322         CtdlRegisterProtoHook(cmd_gtls, "GTLS", "Get SSL/TLS session status");
 323         CtdlRegisterSessionHook(endtls, EVT_STOP, PRIO_STOP + 10);
 324 }
 325
 326
 327 /*
 328  * client_write_ssl() Send binary data to the client encrypted.
 329  */
 330 void client_write_ssl(const char *buf, int nbytes)
 331 {
 332         int retval;
 333         int nremain;
 334         char junk[1];
 335
 336         nremain = nbytes;
 337
 338         while (nremain > 0) {
 339                 if (SSL_want_write(CC->ssl)) {
 340                         if ((SSL_read(CC->ssl, junk, 0)) < 1) {
 341                                 syslog(LOG_DEBUG, "crypto: SSL_read in client_write: %s", ERR_reason_error_string(ERR_get_error()));
 342                         }
 343                 }
 344                 retval =
 345                     SSL_write(CC->ssl, &buf[nbytes - nremain], nremain);
 346                 if (retval < 1) {
 347                         long errval;
 348
 349                         errval = SSL_get_error(CC->ssl, retval);
 350                         if (errval == SSL_ERROR_WANT_READ ||
 351                             errval == SSL_ERROR_WANT_WRITE) {
 352                                 sleep(1);
 353                                 continue;
 354                         }
 355                         syslog(LOG_DEBUG, "crypto: SSL_write got error %ld, ret %d", errval, retval);
 356                         if (retval == -1) {
 357                                 syslog(LOG_DEBUG, "crypto: errno is %d", errno);
 358                         }
 359                         endtls();
 360                         client_write(&buf[nbytes - nremain], nremain);
 361                         return;
 362                 }
 363                 nremain -= retval;
 364         }
 365 }
 366
 367
 368 /*
 369  * read data from the encrypted layer.
 370  */
 371 int client_read_sslbuffer(StrBuf *buf, int timeout)
 372 {
 373         char sbuf[16384]; /* OpenSSL communicates in 16k blocks, so let's speak its native tongue. */
 374         int rlen;
 375         char junk[1];
 376         SSL *pssl = CC->ssl;
 377
 378         if (pssl == NULL) return(-1);
 379
 380         while (1) {
 381                 if (SSL_want_read(pssl)) {
 382                         if ((SSL_write(pssl, junk, 0)) < 1) {
 383                                 syslog(LOG_DEBUG, "crypto: SSL_write in client_read");
 384                         }
 385                 }
 386                 rlen = SSL_read(pssl, sbuf, sizeof(sbuf));
 387                 if (rlen < 1) {
 388                         long errval;
 389
 390                         errval = SSL_get_error(pssl, rlen);
 391                         if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
 392                                 sleep(1);
 393                                 continue;
 394                         }
 395                         syslog(LOG_DEBUG, "crypto: SSL_read got error %ld", errval);
 396                         endtls();
 397                         return (-1);
 398                 }
 399                 StrBufAppendBufPlain(buf, sbuf, rlen, 0);
 400                 return rlen;
 401         }
 402         return (0);
 403 }
 404
 405 int client_readline_sslbuffer(StrBuf *Line, StrBuf *IOBuf, const char **Pos, int timeout)
 406 {
 407         CitContext *CCC = CC;
 408         const char *pos = NULL;
 409         const char *pLF;
 410         int len, rlen;
 411         int nSuccessLess = 0;
 412         const char *pch = NULL;
 413
 414         if ((Line == NULL) || (Pos == NULL) || (IOBuf == NULL))
 415         {
 416                 if (Pos != NULL)
 417                 {
 418                         *Pos = NULL;
 419                 }
 420                 return -1;
 421         }
 422
 423         pos = *Pos;
 424         if ((StrLength(IOBuf) > 0) && (pos != NULL) && (pos < ChrPtr(IOBuf) + StrLength(IOBuf)))
 425         {
 426                 pch = pos;
 427                 pch = strchr(pch, '\n');
 428
 429                 if (pch == NULL) {
 430                         StrBufAppendBufPlain(Line, pos, StrLength(IOBuf) - (pos - ChrPtr(IOBuf)), 0);
 431                         FlushStrBuf(IOBuf);
 432                         *Pos = NULL;
 433                 }
 434                 else {
 435                         int n = 0;
 436                         if ((pch > ChrPtr(IOBuf)) &&
 437                             (*(pch - 1) == '\r')) {
 438                                 n = 1;
 439                         }
 440                         StrBufAppendBufPlain(Line, pos,
 441                                              (pch - pos - n), 0);
 442
 443                         if (StrLength(IOBuf) <= (pch - ChrPtr(IOBuf) + 1)) {
 444                                 FlushStrBuf(IOBuf);
 445                                 *Pos = NULL;
 446                         }
 447                         else
 448                                 *Pos = pch + 1;
 449                         return StrLength(Line);
 450                 }
 451         }
 452
 453         pLF = NULL;
 454         while ((nSuccessLess < timeout) &&
 455                (pLF == NULL) &&
 456                (CCC->ssl != NULL)) {
 457
 458                 rlen = client_read_sslbuffer(IOBuf, timeout);
 459                 if (rlen < 1) {
 460                         return -1;
 461                 }
 462                 else if (rlen > 0) {
 463                         pLF = strchr(ChrPtr(IOBuf), '\n');
 464                 }
 465         }
 466         *Pos = NULL;
 467         if (pLF != NULL) {
 468                 pos = ChrPtr(IOBuf);
 469                 len = pLF - pos;
 470                 if (len > 0 && (*(pLF - 1) == '\r') )
 471                         len --;
 472                 StrBufAppendBufPlain(Line, pos, len, 0);
 473                 if (pLF + 1 >= ChrPtr(IOBuf) + StrLength(IOBuf))
 474                 {
 475                         FlushStrBuf(IOBuf);
 476                 }
 477                 else
 478                         *Pos = pLF + 1;
 479                 return StrLength(Line);
 480         }
 481         return -1;
 482 }
 483
 484
 485 int client_read_sslblob(StrBuf *Target, long bytes, int timeout)
 486 {
 487         long baselen;
 488         long RemainRead;
 489         int retval = 0;
 490         CitContext *CCC = CC;
 491
 492         baselen = StrLength(Target);
 493
 494         if (StrLength(CCC->RecvBuf.Buf) > 0)
 495         {
 496                 long RemainLen;
 497                 long TotalLen;
 498                 const char *pchs;
 499
 500                 if (CCC->RecvBuf.ReadWritePointer == NULL)
 501                 {
 502                         CCC->RecvBuf.ReadWritePointer = ChrPtr(CCC->RecvBuf.Buf);
 503                 }
 504                 pchs = ChrPtr(CCC->RecvBuf.Buf);
 505                 TotalLen = StrLength(CCC->RecvBuf.Buf);
 506                 RemainLen = TotalLen - (pchs - CCC->RecvBuf.ReadWritePointer);
 507                 if (RemainLen > bytes)
 508                 {
 509                         RemainLen = bytes;
 510                 }
 511                 if (RemainLen > 0)
 512                 {
 513                         StrBufAppendBufPlain(Target, CCC->RecvBuf.ReadWritePointer, RemainLen, 0);
 514                         CCC->RecvBuf.ReadWritePointer += RemainLen;
 515                 }
 516                 if ((ChrPtr(CCC->RecvBuf.Buf) + StrLength(CCC->RecvBuf.Buf)) <= CCC->RecvBuf.ReadWritePointer)
 517                 {
 518                         CCC->RecvBuf.ReadWritePointer = NULL;
 519                         FlushStrBuf(CCC->RecvBuf.Buf);
 520                 }
 521         }
 522
 523         if (StrLength(Target) >= bytes + baselen)
 524         {
 525                 return 1;
 526         }
 527
 528         CCC->RecvBuf.ReadWritePointer = NULL;
 529
 530         while ((StrLength(Target) < bytes + baselen) && (retval >= 0))
 531         {
 532                 retval = client_read_sslbuffer(CCC->RecvBuf.Buf, timeout);
 533                 if (retval >= 0) {
 534                         RemainRead = bytes - (StrLength (Target) - baselen);
 535                         if (RemainRead < StrLength(CCC->RecvBuf.Buf))
 536                         {
 537                                 StrBufAppendBufPlain(
 538                                         Target,
 539                                         ChrPtr(CCC->RecvBuf.Buf),
 540                                         RemainRead, 0);
 541                                 CCC->RecvBuf.ReadWritePointer = ChrPtr(CCC->RecvBuf.Buf) + RemainRead;
 542                                 break;
 543                         }
 544                         StrBufAppendBuf(Target, CCC->RecvBuf.Buf, 0); /* todo: Buf > bytes? */
 545                         FlushStrBuf(CCC->RecvBuf.Buf);
 546                 }
 547                 else
 548                 {
 549                         FlushStrBuf(CCC->RecvBuf.Buf);
 550                         return -1;
 551
 552                 }
 553         }
 554         return 1;
 555 }
 556
 557
 558 /*
 559  * CtdlStartTLS() starts SSL/TLS encryption for the current session.  It
 560  * must be supplied with pre-generated strings for responses of "ok," "no
 561  * support for TLS," and "error" so that we can use this in any protocol.
 562  */
 563 void CtdlStartTLS(char *ok_response, char *nosup_response, char *error_response)
 564 {
 565         int retval, bits, alg_bits;
 566
 567         if (!ssl_ctx) {
 568                 syslog(LOG_ERR, "crypto: SSL failed: no ssl_ctx exists?");
 569                 if (nosup_response != NULL) cprintf("%s", nosup_response);
 570                 return;
 571         }
 572         if (!(CC->ssl = SSL_new(ssl_ctx))) {
 573                 syslog(LOG_ERR, "crypto: SSL_new failed: %s", ERR_reason_error_string(ERR_get_error()));
 574                 if (error_response != NULL) {
 575                         cprintf("%s", error_response);
 576                 }
 577                 return;
 578         }
 579         if (!(SSL_set_fd(CC->ssl, CC->client_socket))) {
 580                 syslog(LOG_ERR, "crypto: SSL_set_fd failed: %s", ERR_reason_error_string(ERR_get_error()));
 581                 SSL_free(CC->ssl);
 582                 CC->ssl = NULL;
 583                 if (error_response != NULL) cprintf("%s", error_response);
 584                 return;
 585         }
 586         if (ok_response != NULL) cprintf("%s", ok_response);
 587         retval = SSL_accept(CC->ssl);
 588         if (retval < 1) {
 589                 /*
 590                  * Can't notify the client of an error here; they will
 591                  * discover the problem at the SSL layer and should
 592                  * revert to unencrypted communications.
 593                  */
 594                 long errval;
 595                 char error_string[128];
 596
 597                 errval = SSL_get_error(CC->ssl, retval);
 598                 syslog(LOG_ERR, "crypto: SSL_accept failed: retval=%d, errval=%ld, err=%s",
 599                         retval,
 600                         errval,
 601                         ERR_error_string(errval, error_string)
 602                 );
 603                 SSL_free(CC->ssl);
 604                 CC->ssl = NULL;
 605                 return;
 606         }
 607         // BIO_set_close(CC->ssl->rbio, BIO_NOCLOSE); not needed anymore in openssl 1.1 ?
 608         bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl), &alg_bits);
 609         syslog(LOG_INFO, "crypto: SSL/TLS using %s on %s (%d of %d bits)",
 610                 SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
 611                 SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
 612                 bits, alg_bits
 613         );
 614         CC->redirect_ssl = 1;
 615 }
 616
 617
 618 /*
 619  * cmd_stls() starts SSL/TLS encryption for the current session
 620  */
 621 void cmd_stls(char *params)
 622 {
 623         char ok_response[SIZ];
 624         char nosup_response[SIZ];
 625         char error_response[SIZ];
 626
 627         unbuffer_output();
 628
 629         sprintf(ok_response, "%d Begin TLS negotiation now\n", CIT_OK);
 630         sprintf(nosup_response, "%d TLS not supported here\n", ERROR + CMD_NOT_SUPPORTED);
 631         sprintf(error_response, "%d TLS negotiation error\n", ERROR + INTERNAL_ERROR);
 632
 633         CtdlStartTLS(ok_response, nosup_response, error_response);
 634 }
 635
 636
 637 /*
 638  * cmd_gtls() returns status info about the TLS connection
 639  */
 640 void cmd_gtls(char *params)
 641 {
 642         int bits, alg_bits;
 643
 644         if (!CC->ssl || !CC->redirect_ssl) {
 645                 cprintf("%d Session is not encrypted.\n", ERROR);
 646                 return;
 647         }
 648         bits =
 649             SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl),
 650                                 &alg_bits);
 651         cprintf("%d %s|%s|%d|%d\n", CIT_OK,
 652                 SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
 653                 SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
 654                 alg_bits, bits);
 655 }
 656
 657
 658 /*
 659  * endtls() shuts down the TLS connection
 660  *
 661  * WARNING:  This may make your session vulnerable to a known plaintext
 662  * attack in the current implmentation.
 663  */
 664 void endtls(void)
 665 {
 666         if (!CC->ssl) {
 667                 CC->redirect_ssl = 0;
 668                 return;
 669         }
 670
 671         syslog(LOG_INFO, "crypto: ending SSL/TLS");
 672         SSL_shutdown(CC->ssl);
 673         SSL_free(CC->ssl);
 674         CC->ssl = NULL;
 675         CC->redirect_ssl = 0;
 676 }
 677
 678
 679 /*
 680  * ssl_lock() callback for OpenSSL mutex locks
 681  */
 682 void ssl_lock(int mode, int n, const char *file, int line)
 683 {
 684         if (mode & CRYPTO_LOCK)
 685         {
 686                 pthread_mutex_lock(SSLCritters[n]);
 687         }
 688         else {
 689                 pthread_mutex_unlock(SSLCritters[n]);
 690         }
 691 }
 692 #endif                          /* HAVE_OPENSSL */