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
 281                                         ASN1_INTEGER_set(X509_get_serialNumber(cer), 0);
 282                                         X509_set_issuer_name(cer, req->req_info->subject);
 283                                         X509_set_subject_name(cer, req->req_info->subject);
 284                                         X509_gmtime_adj(X509_get_notBefore(cer),0);
 285                                         X509_gmtime_adj(X509_get_notAfter(cer),(long)60*60*24*SIGN_DAYS);
 286                                         req_pkey = X509_REQ_get_pubkey(req);
 287                                         X509_set_pubkey(cer, req_pkey);
 288                                         EVP_PKEY_free(req_pkey);
 289
 290                                         /* Sign the cert */
 291                                         if (!X509_sign(cer, pk, EVP_md5())) {
 292                                                 syslog(LOG_ERR, "crypto: X509_sign() error");
 293                                         }
 294                                         else {
 295                                                 /* Write it to disk. */
 296                                                 fp = fopen(file_crpt_file_cer, "w");
 297                                                 if (fp != NULL) {
 298                                                         chmod(file_crpt_file_cer, 0600);
 299                                                         PEM_write_X509(fp, cer);
 300                                                         fclose(fp);
 301                                                 }
 302                                         }
 303                                         X509_free(cer);
 304                                 }
 305                         }
 306
 307                         RSA_free(rsa);
 308                 }
 309         }
 310
 311
 312         /*
 313          * Now try to bind to the key and certificate.
 314          */
 315         SSL_CTX_use_certificate_chain_file(ssl_ctx, file_crpt_file_cer);
 316         SSL_CTX_use_PrivateKey_file(ssl_ctx, file_crpt_file_key, SSL_FILETYPE_PEM);
 317         if ( !SSL_CTX_check_private_key(ssl_ctx) ) {
 318                 syslog(LOG_ERR, "crypto: cannot install certificate: %s", ERR_reason_error_string(ERR_get_error()));
 319         }
 320
 321         /* Finally let the server know we're here */
 322         CtdlRegisterProtoHook(cmd_stls, "STLS", "Start SSL/TLS session");
 323         CtdlRegisterProtoHook(cmd_gtls, "GTLS", "Get SSL/TLS session status");
 324         CtdlRegisterSessionHook(endtls, EVT_STOP, PRIO_STOP + 10);
 325 }
 326
 327
 328 /*
 329  * client_write_ssl() Send binary data to the client encrypted.
 330  */
 331 void client_write_ssl(const char *buf, int nbytes)
 332 {
 333         int retval;
 334         int nremain;
 335         char junk[1];
 336
 337         nremain = nbytes;
 338
 339         while (nremain > 0) {
 340                 if (SSL_want_write(CC->ssl)) {
 341                         if ((SSL_read(CC->ssl, junk, 0)) < 1) {
 342                                 syslog(LOG_DEBUG, "crypto: SSL_read in client_write: %s", ERR_reason_error_string(ERR_get_error()));
 343                         }
 344                 }
 345                 retval =
 346                     SSL_write(CC->ssl, &buf[nbytes - nremain], nremain);
 347                 if (retval < 1) {
 348                         long errval;
 349
 350                         errval = SSL_get_error(CC->ssl, retval);
 351                         if (errval == SSL_ERROR_WANT_READ ||
 352                             errval == SSL_ERROR_WANT_WRITE) {
 353                                 sleep(1);
 354                                 continue;
 355                         }
 356                         syslog(LOG_DEBUG, "crypto: SSL_write got error %ld, ret %d", errval, retval);
 357                         if (retval == -1) {
 358                                 syslog(LOG_DEBUG, "crypto: errno is %d", errno);
 359                         }
 360                         endtls();
 361                         client_write(&buf[nbytes - nremain], nremain);
 362                         return;
 363                 }
 364                 nremain -= retval;
 365         }
 366 }
 367
 368
 369 /*
 370  * read data from the encrypted layer.
 371  */
 372 int client_read_sslbuffer(StrBuf *buf, int timeout)
 373 {
 374         char sbuf[16384]; /* OpenSSL communicates in 16k blocks, so let's speak its native tongue. */
 375         int rlen;
 376         char junk[1];
 377         SSL *pssl = CC->ssl;
 378
 379         if (pssl == NULL) return(-1);
 380
 381         while (1) {
 382                 if (SSL_want_read(pssl)) {
 383                         if ((SSL_write(pssl, junk, 0)) < 1) {
 384                                 syslog(LOG_DEBUG, "crypto: SSL_write in client_read");
 385                         }
 386                 }
 387                 rlen = SSL_read(pssl, sbuf, sizeof(sbuf));
 388                 if (rlen < 1) {
 389                         long errval;
 390
 391                         errval = SSL_get_error(pssl, rlen);
 392                         if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
 393                                 sleep(1);
 394                                 continue;
 395                         }
 396                         syslog(LOG_DEBUG, "crypto: SSL_read got error %ld", errval);
 397                         endtls();
 398                         return (-1);
 399                 }
 400                 StrBufAppendBufPlain(buf, sbuf, rlen, 0);
 401                 return rlen;
 402         }
 403         return (0);
 404 }
 405
 406 int client_readline_sslbuffer(StrBuf *Line, StrBuf *IOBuf, const char **Pos, int timeout)
 407 {
 408         CitContext *CCC = CC;
 409         const char *pos = NULL;
 410         const char *pLF;
 411         int len, rlen;
 412         int nSuccessLess = 0;
 413         const char *pch = NULL;
 414
 415         if ((Line == NULL) || (Pos == NULL) || (IOBuf == NULL))
 416         {
 417                 if (Pos != NULL)
 418                 {
 419                         *Pos = NULL;
 420                 }
 421                 return -1;
 422         }
 423
 424         pos = *Pos;
 425         if ((StrLength(IOBuf) > 0) && (pos != NULL) && (pos < ChrPtr(IOBuf) + StrLength(IOBuf)))
 426         {
 427                 pch = pos;
 428                 pch = strchr(pch, '\n');
 429
 430                 if (pch == NULL) {
 431                         StrBufAppendBufPlain(Line, pos, StrLength(IOBuf) - (pos - ChrPtr(IOBuf)), 0);
 432                         FlushStrBuf(IOBuf);
 433                         *Pos = NULL;
 434                 }
 435                 else {
 436                         int n = 0;
 437                         if ((pch > ChrPtr(IOBuf)) &&
 438                             (*(pch - 1) == '\r')) {
 439                                 n = 1;
 440                         }
 441                         StrBufAppendBufPlain(Line, pos,
 442                                              (pch - pos - n), 0);
 443
 444                         if (StrLength(IOBuf) <= (pch - ChrPtr(IOBuf) + 1)) {
 445                                 FlushStrBuf(IOBuf);
 446                                 *Pos = NULL;
 447                         }
 448                         else
 449                                 *Pos = pch + 1;
 450                         return StrLength(Line);
 451                 }
 452         }
 453
 454         pLF = NULL;
 455         while ((nSuccessLess < timeout) &&
 456                (pLF == NULL) &&
 457                (CCC->ssl != NULL)) {
 458
 459                 rlen = client_read_sslbuffer(IOBuf, timeout);
 460                 if (rlen < 1) {
 461                         return -1;
 462                 }
 463                 else if (rlen > 0) {
 464                         pLF = strchr(ChrPtr(IOBuf), '\n');
 465                 }
 466         }
 467         *Pos = NULL;
 468         if (pLF != NULL) {
 469                 pos = ChrPtr(IOBuf);
 470                 len = pLF - pos;
 471                 if (len > 0 && (*(pLF - 1) == '\r') )
 472                         len --;
 473                 StrBufAppendBufPlain(Line, pos, len, 0);
 474                 if (pLF + 1 >= ChrPtr(IOBuf) + StrLength(IOBuf))
 475                 {
 476                         FlushStrBuf(IOBuf);
 477                 }
 478                 else
 479                         *Pos = pLF + 1;
 480                 return StrLength(Line);
 481         }
 482         return -1;
 483 }
 484
 485
 486 int client_read_sslblob(StrBuf *Target, long bytes, int timeout)
 487 {
 488         long baselen;
 489         long RemainRead;
 490         int retval = 0;
 491         CitContext *CCC = CC;
 492
 493         baselen = StrLength(Target);
 494
 495         if (StrLength(CCC->RecvBuf.Buf) > 0)
 496         {
 497                 long RemainLen;
 498                 long TotalLen;
 499                 const char *pchs;
 500
 501                 if (CCC->RecvBuf.ReadWritePointer == NULL)
 502                 {
 503                         CCC->RecvBuf.ReadWritePointer = ChrPtr(CCC->RecvBuf.Buf);
 504                 }
 505                 pchs = ChrPtr(CCC->RecvBuf.Buf);
 506                 TotalLen = StrLength(CCC->RecvBuf.Buf);
 507                 RemainLen = TotalLen - (pchs - CCC->RecvBuf.ReadWritePointer);
 508                 if (RemainLen > bytes)
 509                 {
 510                         RemainLen = bytes;
 511                 }
 512                 if (RemainLen > 0)
 513                 {
 514                         StrBufAppendBufPlain(Target, CCC->RecvBuf.ReadWritePointer, RemainLen, 0);
 515                         CCC->RecvBuf.ReadWritePointer += RemainLen;
 516                 }
 517                 if ((ChrPtr(CCC->RecvBuf.Buf) + StrLength(CCC->RecvBuf.Buf)) <= CCC->RecvBuf.ReadWritePointer)
 518                 {
 519                         CCC->RecvBuf.ReadWritePointer = NULL;
 520                         FlushStrBuf(CCC->RecvBuf.Buf);
 521                 }
 522         }
 523
 524         if (StrLength(Target) >= bytes + baselen)
 525         {
 526                 return 1;
 527         }
 528
 529         CCC->RecvBuf.ReadWritePointer = NULL;
 530
 531         while ((StrLength(Target) < bytes + baselen) && (retval >= 0))
 532         {
 533                 retval = client_read_sslbuffer(CCC->RecvBuf.Buf, timeout);
 534                 if (retval >= 0) {
 535                         RemainRead = bytes - (StrLength (Target) - baselen);
 536                         if (RemainRead < StrLength(CCC->RecvBuf.Buf))
 537                         {
 538                                 StrBufAppendBufPlain(
 539                                         Target,
 540                                         ChrPtr(CCC->RecvBuf.Buf),
 541                                         RemainRead, 0);
 542                                 CCC->RecvBuf.ReadWritePointer = ChrPtr(CCC->RecvBuf.Buf) + RemainRead;
 543                                 break;
 544                         }
 545                         StrBufAppendBuf(Target, CCC->RecvBuf.Buf, 0); /* todo: Buf > bytes? */
 546                         FlushStrBuf(CCC->RecvBuf.Buf);
 547                 }
 548                 else
 549                 {
 550                         FlushStrBuf(CCC->RecvBuf.Buf);
 551                         return -1;
 552
 553                 }
 554         }
 555         return 1;
 556 }
 557
 558
 559 /*
 560  * CtdlStartTLS() starts SSL/TLS encryption for the current session.  It
 561  * must be supplied with pre-generated strings for responses of "ok," "no
 562  * support for TLS," and "error" so that we can use this in any protocol.
 563  */
 564 void CtdlStartTLS(char *ok_response, char *nosup_response, char *error_response)
 565 {
 566         int retval, bits, alg_bits;
 567
 568         if (!ssl_ctx) {
 569                 syslog(LOG_ERR, "crypto: SSL failed: no ssl_ctx exists?");
 570                 if (nosup_response != NULL) cprintf("%s", nosup_response);
 571                 return;
 572         }
 573         if (!(CC->ssl = SSL_new(ssl_ctx))) {
 574                 syslog(LOG_ERR, "crypto: SSL_new failed: %s", ERR_reason_error_string(ERR_get_error()));
 575                 if (error_response != NULL) {
 576                         cprintf("%s", error_response);
 577                 }
 578                 return;
 579         }
 580         if (!(SSL_set_fd(CC->ssl, CC->client_socket))) {
 581                 syslog(LOG_ERR, "crypto: SSL_set_fd failed: %s", ERR_reason_error_string(ERR_get_error()));
 582                 SSL_free(CC->ssl);
 583                 CC->ssl = NULL;
 584                 if (error_response != NULL) cprintf("%s", error_response);
 585                 return;
 586         }
 587         if (ok_response != NULL) cprintf("%s", ok_response);
 588         retval = SSL_accept(CC->ssl);
 589         if (retval < 1) {
 590                 /*
 591                  * Can't notify the client of an error here; they will
 592                  * discover the problem at the SSL layer and should
 593                  * revert to unencrypted communications.
 594                  */
 595                 long errval;
 596                 char error_string[128];
 597
 598                 errval = SSL_get_error(CC->ssl, retval);
 599                 syslog(LOG_ERR, "crypto: SSL_accept failed: retval=%d, errval=%ld, err=%s",
 600                         retval,
 601                         errval,
 602                         ERR_error_string(errval, error_string)
 603                 );
 604                 SSL_free(CC->ssl);
 605                 CC->ssl = NULL;
 606                 return;
 607         }
 608         BIO_set_close(CC->ssl->rbio, BIO_NOCLOSE);
 609         bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl), &alg_bits);
 610         syslog(LOG_INFO, "crypto: SSL/TLS using %s on %s (%d of %d bits)",
 611                 SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
 612                 SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
 613                 bits, alg_bits
 614         );
 615         CC->redirect_ssl = 1;
 616 }
 617
 618
 619 /*
 620  * cmd_stls() starts SSL/TLS encryption for the current session
 621  */
 622 void cmd_stls(char *params)
 623 {
 624         char ok_response[SIZ];
 625         char nosup_response[SIZ];
 626         char error_response[SIZ];
 627
 628         unbuffer_output();
 629
 630         sprintf(ok_response, "%d Begin TLS negotiation now\n", CIT_OK);
 631         sprintf(nosup_response, "%d TLS not supported here\n", ERROR + CMD_NOT_SUPPORTED);
 632         sprintf(error_response, "%d TLS negotiation error\n", ERROR + INTERNAL_ERROR);
 633
 634         CtdlStartTLS(ok_response, nosup_response, error_response);
 635 }
 636
 637
 638 /*
 639  * cmd_gtls() returns status info about the TLS connection
 640  */
 641 void cmd_gtls(char *params)
 642 {
 643         int bits, alg_bits;
 644
 645         if (!CC->ssl || !CC->redirect_ssl) {
 646                 cprintf("%d Session is not encrypted.\n", ERROR);
 647                 return;
 648         }
 649         bits =
 650             SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl),
 651                                 &alg_bits);
 652         cprintf("%d %s|%s|%d|%d\n", CIT_OK,
 653                 SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
 654                 SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
 655                 alg_bits, bits);
 656 }
 657
 658
 659 /*
 660  * endtls() shuts down the TLS connection
 661  *
 662  * WARNING:  This may make your session vulnerable to a known plaintext
 663  * attack in the current implmentation.
 664  */
 665 void endtls(void)
 666 {
 667         if (!CC->ssl) {
 668                 CC->redirect_ssl = 0;
 669                 return;
 670         }
 671
 672         syslog(LOG_INFO, "crypto: ending SSL/TLS");
 673         SSL_shutdown(CC->ssl);
 674         SSL_free(CC->ssl);
 675         CC->ssl = NULL;
 676         CC->redirect_ssl = 0;
 677 }
 678
 679
 680 /*
 681  * ssl_lock() callback for OpenSSL mutex locks
 682  */
 683 void ssl_lock(int mode, int n, const char *file, int line)
 684 {
 685         if (mode & CRYPTO_LOCK)
 686         {
 687                 pthread_mutex_lock(SSLCritters[n]);
 688         }
 689         else {
 690                 pthread_mutex_unlock(SSLCritters[n]);
 691         }
 692 }
 693 #endif                          /* HAVE_OPENSSL */