citadel/modules/crypto/serv_crypto.c

   1 /*
   2  * Copyright (c) 1987-2017 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 void init_ssl(void)
  73 {
  74         const SSL_METHOD *ssl_method;
  75         RSA *rsa=NULL;
  76         X509_REQ *req = NULL;
  77         X509 *cer = NULL;
  78         EVP_PKEY *pk = NULL;
  79         EVP_PKEY *req_pkey = NULL;
  80         X509_NAME *name = NULL;
  81         FILE *fp;
  82
  83         if (!access(EGD_POOL, F_OK))
  84                 RAND_egd(EGD_POOL);
  85
  86         if (!RAND_status()) {
  87                 syslog(LOG_ERR, "PRNG not adequately seeded, won't do SSL/TLS");
  88                 return;
  89         }
  90         SSLCritters = malloc(CRYPTO_num_locks() * sizeof(pthread_mutex_t *));
  91         if (!SSLCritters) {
  92                 syslog(LOG_ERR, "citserver: can't allocate memory!!");
  93                 /* Nothing's been initialized, just die */
  94                 exit(1);
  95         } else {
  96                 int a;
  97
  98                 for (a = 0; a < CRYPTO_num_locks(); a++) {
  99                         SSLCritters[a] = malloc(sizeof(pthread_mutex_t));
 100                         if (!SSLCritters[a]) {
 101                                 syslog(LOG_EMERG, "citserver: can't allocate memory!!");
 102                                 /* Nothing's been initialized, just die */
 103                                 exit(1);
 104                         }
 105                         pthread_mutex_init(SSLCritters[a], NULL);
 106                 }
 107         }
 108
 109         /*
 110          * Initialize SSL transport layer
 111          */
 112         SSL_library_init();
 113         SSL_load_error_strings();
 114         ssl_method = SSLv23_server_method();
 115         if (!(ssl_ctx = SSL_CTX_new(ssl_method))) {
 116                 syslog(LOG_ERR, "SSL_CTX_new failed: %s", ERR_reason_error_string(ERR_get_error()));
 117                 return;
 118         }
 119         if (!(SSL_CTX_set_cipher_list(ssl_ctx, CIT_CIPHERS))) {
 120                 syslog(LOG_ERR, "SSL: No ciphers available");
 121                 SSL_CTX_free(ssl_ctx);
 122                 ssl_ctx = NULL;
 123                 return;
 124         }
 125
 126         CRYPTO_set_locking_callback(ssl_lock);
 127         CRYPTO_set_id_callback(id_callback);
 128
 129         /* Get our certificates in order.
 130          * First, create the key/cert directory if it's not there already...
 131          */
 132         mkdir(ctdl_key_dir, 0700);
 133
 134         /*
 135          * Generate a key pair if we don't have one.
 136          */
 137         if (access(file_crpt_file_key, R_OK) != 0) {
 138                 syslog(LOG_INFO, "Generating RSA key pair.");
 139                 rsa = RSA_generate_key(1024,    /* modulus size */
 140                                         65537,  /* exponent */
 141                                         NULL,   /* no callback */
 142                                         NULL);  /* no callback */
 143                 if (rsa == NULL) {
 144                         syslog(LOG_ERR, "Key generation failed: %s", ERR_reason_error_string(ERR_get_error()));
 145                 }
 146                 if (rsa != NULL) {
 147                         fp = fopen(file_crpt_file_key, "w");
 148                         if (fp != NULL) {
 149                                 chmod(file_crpt_file_key, 0600);
 150                                 if (PEM_write_RSAPrivateKey(fp, /* the file */
 151                                                         rsa,    /* the key */
 152                                                         NULL,   /* no enc */
 153                                                         NULL,   /* no passphr */
 154                                                         0,      /* no passphr */
 155                                                         NULL,   /* no callbk */
 156                                                         NULL    /* no callbk */
 157                                 ) != 1) {
 158                                         syslog(LOG_ERR, "Cannot write key: %s", ERR_reason_error_string(ERR_get_error()));
 159                                         unlink(file_crpt_file_key);
 160                                 }
 161                                 fclose(fp);
 162                         }
 163                         RSA_free(rsa);
 164                 }
 165         }
 166
 167         /*
 168          * If there is no certificate file on disk, we will be generating a self-signed certificate
 169          * in the next step.  Therefore, if we have neither a CSR nor a certificate, generate
 170          * the CSR in this step so that the next step may commence.
 171          */
 172         if ( (access(file_crpt_file_cer, R_OK) != 0) && (access(file_crpt_file_csr, R_OK) != 0) ) {
 173                 syslog(LOG_INFO, "Generating a generic certificate signing request.");
 174
 175                 /*
 176                  * Read our key from the file.  No, we don't just keep this
 177                  * in memory from the above key-generation function, because
 178                  * there is the possibility that the key was already on disk
 179                  * and we didn't just generate it now.
 180                  */
 181                 fp = fopen(file_crpt_file_key, "r");
 182                 if (fp) {
 183                         rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 184                         fclose(fp);
 185                 }
 186
 187                 if (rsa) {
 188
 189                         /* Create a public key from the private key */
 190                         if (pk=EVP_PKEY_new(), pk != NULL) {
 191                                 EVP_PKEY_assign_RSA(pk, rsa);
 192                                 if (req = X509_REQ_new(), req != NULL) {
 193
 194                                         /* Set the public key */
 195                                         X509_REQ_set_pubkey(req, pk);
 196                                         X509_REQ_set_version(req, 0L);
 197
 198                                         name = X509_REQ_get_subject_name(req);
 199
 200                                         /* Tell it who we are */
 201                                         X509_NAME_add_entry_by_txt(name, "C", MBSTRING_ASC, (unsigned const char *)"ZZ", -1, -1, 0);
 202                                         X509_NAME_add_entry_by_txt(name, "ST", MBSTRING_ASC, (unsigned const char *)"The World", -1, -1, 0);
 203                                         X509_NAME_add_entry_by_txt(name, "L", MBSTRING_ASC, (unsigned const char *)"My Location", -1, -1, 0);
 204                                         X509_NAME_add_entry_by_txt(name, "O", MBSTRING_ASC, (unsigned const char *)"Generic certificate", -1, -1, 0);
 205                                         X509_NAME_add_entry_by_txt(name, "OU", MBSTRING_ASC, (unsigned const char *)"Citadel server", -1, -1, 0);
 206                                         X509_NAME_add_entry_by_txt(name, "CN", MBSTRING_ASC, (unsigned const char *)"*", -1, -1, 0);
 207                                         X509_REQ_set_subject_name(req, name);
 208
 209                                         /* Sign the CSR */
 210                                         if (!X509_REQ_sign(req, pk, EVP_md5())) {
 211                                                 syslog(LOG_ERR, "X509_REQ_sign(): error");
 212                                         }
 213                                         else {
 214                                                 /* Write it to disk. */
 215                                                 fp = fopen(file_crpt_file_csr, "w");
 216                                                 if (fp != NULL) {
 217                                                         chmod(file_crpt_file_csr, 0600);
 218                                                         PEM_write_X509_REQ(fp, req);
 219                                                         fclose(fp);
 220                                                 }
 221                                         }
 222
 223                                         X509_REQ_free(req);
 224                                 }
 225                         }
 226
 227                         RSA_free(rsa);
 228                 }
 229
 230                 else {
 231                         syslog(LOG_ERR, "Unable to read private key.");
 232                 }
 233         }
 234
 235
 236         /*
 237          * Generate a self-signed certificate if we don't have one.
 238          */
 239         if (access(file_crpt_file_cer, R_OK) != 0) {
 240                 syslog(LOG_INFO, "Generating a generic self-signed certificate.");
 241
 242                 /* Same deal as before: always read the key from disk because
 243                  * it may or may not have just been generated.
 244                  */
 245                 fp = fopen(file_crpt_file_key, "r");
 246                 if (fp) {
 247                         rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 248                         fclose(fp);
 249                 }
 250
 251                 /* This also holds true for the CSR. */
 252                 req = NULL;
 253                 cer = NULL;
 254                 pk = NULL;
 255                 if (rsa) {
 256                         if (pk=EVP_PKEY_new(), pk != NULL) {
 257                                 EVP_PKEY_assign_RSA(pk, rsa);
 258                         }
 259
 260                         fp = fopen(file_crpt_file_csr, "r");
 261                         if (fp) {
 262                                 req = PEM_read_X509_REQ(fp, NULL, NULL, NULL);
 263                                 fclose(fp);
 264                         }
 265
 266                         if (req) {
 267                                 if (cer = X509_new(), cer != NULL) {
 268
 269                                         ASN1_INTEGER_set(X509_get_serialNumber(cer), 0);
 270                                         X509_set_issuer_name(cer, req->req_info->subject);
 271                                         X509_set_subject_name(cer, req->req_info->subject);
 272                                         X509_gmtime_adj(X509_get_notBefore(cer),0);
 273                                         X509_gmtime_adj(X509_get_notAfter(cer),(long)60*60*24*SIGN_DAYS);
 274                                         req_pkey = X509_REQ_get_pubkey(req);
 275                                         X509_set_pubkey(cer, req_pkey);
 276                                         EVP_PKEY_free(req_pkey);
 277
 278                                         /* Sign the cert */
 279                                         if (!X509_sign(cer, pk, EVP_md5())) {
 280                                                 syslog(LOG_ERR, "X509_sign(): error");
 281                                         }
 282                                         else {
 283                                                 /* Write it to disk. */
 284                                                 fp = fopen(file_crpt_file_cer, "w");
 285                                                 if (fp != NULL) {
 286                                                         chmod(file_crpt_file_cer, 0600);
 287                                                         PEM_write_X509(fp, cer);
 288                                                         fclose(fp);
 289                                                 }
 290                                         }
 291                                         X509_free(cer);
 292                                 }
 293                         }
 294
 295                         RSA_free(rsa);
 296                 }
 297         }
 298
 299
 300         /*
 301          * Now try to bind to the key and certificate.
 302          */
 303         SSL_CTX_use_certificate_chain_file(ssl_ctx, file_crpt_file_cer);
 304         SSL_CTX_use_PrivateKey_file(ssl_ctx, file_crpt_file_key, SSL_FILETYPE_PEM);
 305         if ( !SSL_CTX_check_private_key(ssl_ctx) ) {
 306                 syslog(LOG_ERR, "Cannot install certificate: %s", ERR_reason_error_string(ERR_get_error()));
 307         }
 308
 309         /* Finally let the server know we're here */
 310         CtdlRegisterProtoHook(cmd_stls, "STLS", "Start SSL/TLS session");
 311         CtdlRegisterProtoHook(cmd_gtls, "GTLS", "Get SSL/TLS session status");
 312         CtdlRegisterSessionHook(endtls, EVT_STOP, PRIO_STOP + 10);
 313 }
 314
 315
 316 /*
 317  * client_write_ssl() Send binary data to the client encrypted.
 318  */
 319 void client_write_ssl(const char *buf, int nbytes)
 320 {
 321         int retval;
 322         int nremain;
 323         char junk[1];
 324
 325         nremain = nbytes;
 326
 327         while (nremain > 0) {
 328                 if (SSL_want_write(CC->ssl)) {
 329                         if ((SSL_read(CC->ssl, junk, 0)) < 1) {
 330                                 syslog(LOG_DEBUG, "SSL_read in client_write: %s", ERR_reason_error_string(ERR_get_error()));
 331                         }
 332                 }
 333                 retval =
 334                     SSL_write(CC->ssl, &buf[nbytes - nremain], nremain);
 335                 if (retval < 1) {
 336                         long errval;
 337
 338                         errval = SSL_get_error(CC->ssl, retval);
 339                         if (errval == SSL_ERROR_WANT_READ ||
 340                             errval == SSL_ERROR_WANT_WRITE) {
 341                                 sleep(1);
 342                                 continue;
 343                         }
 344                         syslog(LOG_DEBUG, "SSL_write got error %ld, ret %d", errval, retval);
 345                         if (retval == -1)
 346                                 syslog(LOG_DEBUG, "errno is %d", errno);
 347                         endtls();
 348                         client_write(&buf[nbytes - nremain], nremain);
 349                         return;
 350                 }
 351                 nremain -= retval;
 352         }
 353 }
 354
 355
 356 /*
 357  * read data from the encrypted layer.
 358  */
 359 int client_read_sslbuffer(StrBuf *buf, int timeout)
 360 {
 361         char sbuf[16384]; /* OpenSSL communicates in 16k blocks, so let's speak its native tongue. */
 362         int rlen;
 363         char junk[1];
 364         SSL *pssl = CC->ssl;
 365
 366         if (pssl == NULL) return(-1);
 367
 368         while (1) {
 369                 if (SSL_want_read(pssl)) {
 370                         if ((SSL_write(pssl, junk, 0)) < 1) {
 371                                 syslog(LOG_DEBUG, "SSL_write in client_read");
 372                         }
 373                 }
 374                 rlen = SSL_read(pssl, sbuf, sizeof(sbuf));
 375                 if (rlen < 1) {
 376                         long errval;
 377
 378                         errval = SSL_get_error(pssl, rlen);
 379                         if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
 380                                 sleep(1);
 381                                 continue;
 382                         }
 383                         syslog(LOG_DEBUG, "SSL_read got error %ld", errval);
 384                         endtls();
 385                         return (-1);
 386                 }
 387                 StrBufAppendBufPlain(buf, sbuf, rlen, 0);
 388                 return rlen;
 389         }
 390         return (0);
 391 }
 392
 393 int client_readline_sslbuffer(StrBuf *Line, StrBuf *IOBuf, const char **Pos, int timeout)
 394 {
 395         CitContext *CCC = CC;
 396         const char *pos = NULL;
 397         const char *pLF;
 398         int len, rlen;
 399         int nSuccessLess = 0;
 400         const char *pch = NULL;
 401
 402         if ((Line == NULL) || (Pos == NULL) || (IOBuf == NULL))
 403         {
 404                 if (Pos != NULL)
 405                 {
 406                         *Pos = NULL;
 407                 }
 408                 return -1;
 409         }
 410
 411         pos = *Pos;
 412         if ((StrLength(IOBuf) > 0) && (pos != NULL) && (pos < ChrPtr(IOBuf) + StrLength(IOBuf)))
 413         {
 414                 pch = pos;
 415                 pch = strchr(pch, '\n');
 416
 417                 if (pch == NULL) {
 418                         StrBufAppendBufPlain(Line, pos, StrLength(IOBuf) - (pos - ChrPtr(IOBuf)), 0);
 419                         FlushStrBuf(IOBuf);
 420                         *Pos = NULL;
 421                 }
 422                 else {
 423                         int n = 0;
 424                         if ((pch > ChrPtr(IOBuf)) &&
 425                             (*(pch - 1) == '\r')) {
 426                                 n = 1;
 427                         }
 428                         StrBufAppendBufPlain(Line, pos,
 429                                              (pch - pos - n), 0);
 430
 431                         if (StrLength(IOBuf) <= (pch - ChrPtr(IOBuf) + 1)) {
 432                                 FlushStrBuf(IOBuf);
 433                                 *Pos = NULL;
 434                         }
 435                         else
 436                                 *Pos = pch + 1;
 437                         return StrLength(Line);
 438                 }
 439         }
 440
 441         pLF = NULL;
 442         while ((nSuccessLess < timeout) &&
 443                (pLF == NULL) &&
 444                (CCC->ssl != NULL)) {
 445
 446                 rlen = client_read_sslbuffer(IOBuf, timeout);
 447                 if (rlen < 1) {
 448                         return -1;
 449                 }
 450                 else if (rlen > 0) {
 451                         pLF = strchr(ChrPtr(IOBuf), '\n');
 452                 }
 453         }
 454         *Pos = NULL;
 455         if (pLF != NULL) {
 456                 pos = ChrPtr(IOBuf);
 457                 len = pLF - pos;
 458                 if (len > 0 && (*(pLF - 1) == '\r') )
 459                         len --;
 460                 StrBufAppendBufPlain(Line, pos, len, 0);
 461                 if (pLF + 1 >= ChrPtr(IOBuf) + StrLength(IOBuf))
 462                 {
 463                         FlushStrBuf(IOBuf);
 464                 }
 465                 else
 466                         *Pos = pLF + 1;
 467                 return StrLength(Line);
 468         }
 469         return -1;
 470 }
 471
 472
 473 int client_read_sslblob(StrBuf *Target, long bytes, int timeout)
 474 {
 475         long baselen;
 476         long RemainRead;
 477         int retval = 0;
 478         CitContext *CCC = CC;
 479
 480         baselen = StrLength(Target);
 481
 482         if (StrLength(CCC->RecvBuf.Buf) > 0)
 483         {
 484                 long RemainLen;
 485                 long TotalLen;
 486                 const char *pchs;
 487
 488                 if (CCC->RecvBuf.ReadWritePointer == NULL)
 489                 {
 490                         CCC->RecvBuf.ReadWritePointer = ChrPtr(CCC->RecvBuf.Buf);
 491                 }
 492                 pchs = ChrPtr(CCC->RecvBuf.Buf);
 493                 TotalLen = StrLength(CCC->RecvBuf.Buf);
 494                 RemainLen = TotalLen - (pchs - CCC->RecvBuf.ReadWritePointer);
 495                 if (RemainLen > bytes)
 496                 {
 497                         RemainLen = bytes;
 498                 }
 499                 if (RemainLen > 0)
 500                 {
 501                         StrBufAppendBufPlain(Target, CCC->RecvBuf.ReadWritePointer, RemainLen, 0);
 502                         CCC->RecvBuf.ReadWritePointer += RemainLen;
 503                 }
 504                 if ((ChrPtr(CCC->RecvBuf.Buf) + StrLength(CCC->RecvBuf.Buf)) <= CCC->RecvBuf.ReadWritePointer)
 505                 {
 506                         CCC->RecvBuf.ReadWritePointer = NULL;
 507                         FlushStrBuf(CCC->RecvBuf.Buf);
 508                 }
 509         }
 510
 511         if (StrLength(Target) >= bytes + baselen)
 512         {
 513                 return 1;
 514         }
 515
 516         CCC->RecvBuf.ReadWritePointer = NULL;
 517
 518         while ((StrLength(Target) < bytes + baselen) && (retval >= 0))
 519         {
 520                 retval = client_read_sslbuffer(CCC->RecvBuf.Buf, timeout);
 521                 if (retval >= 0) {
 522                         RemainRead = bytes - (StrLength (Target) - baselen);
 523                         if (RemainRead < StrLength(CCC->RecvBuf.Buf))
 524                         {
 525                                 StrBufAppendBufPlain(
 526                                         Target,
 527                                         ChrPtr(CCC->RecvBuf.Buf),
 528                                         RemainRead, 0);
 529                                 CCC->RecvBuf.ReadWritePointer = ChrPtr(CCC->RecvBuf.Buf) + RemainRead;
 530                                 break;
 531                         }
 532                         StrBufAppendBuf(Target, CCC->RecvBuf.Buf, 0); /* todo: Buf > bytes? */
 533                         FlushStrBuf(CCC->RecvBuf.Buf);
 534                 }
 535                 else
 536                 {
 537                         FlushStrBuf(CCC->RecvBuf.Buf);
 538                         return -1;
 539
 540                 }
 541         }
 542         return 1;
 543 }
 544
 545
 546 /*
 547  * CtdlStartTLS() starts SSL/TLS encryption for the current session.  It
 548  * must be supplied with pre-generated strings for responses of "ok," "no
 549  * support for TLS," and "error" so that we can use this in any protocol.
 550  */
 551 void CtdlStartTLS(char *ok_response, char *nosup_response, char *error_response)
 552 {
 553         int retval, bits, alg_bits;
 554
 555         if (!ssl_ctx) {
 556                 syslog(LOG_ERR, "SSL failed: no ssl_ctx exists?");
 557                 if (nosup_response != NULL) cprintf("%s", nosup_response);
 558                 return;
 559         }
 560         if (!(CC->ssl = SSL_new(ssl_ctx))) {
 561                 syslog(LOG_ERR, "SSL_new failed: %s",
 562                                 ERR_reason_error_string(ERR_get_error()));
 563                 if (error_response != NULL) cprintf("%s", error_response);
 564                 return;
 565         }
 566         if (!(SSL_set_fd(CC->ssl, CC->client_socket))) {
 567                 syslog(LOG_ERR, "SSL_set_fd failed: %s", ERR_reason_error_string(ERR_get_error()));
 568                 SSL_free(CC->ssl);
 569                 CC->ssl = NULL;
 570                 if (error_response != NULL) cprintf("%s", error_response);
 571                 return;
 572         }
 573         if (ok_response != NULL) cprintf("%s", ok_response);
 574         retval = SSL_accept(CC->ssl);
 575         if (retval < 1) {
 576                 /*
 577                  * Can't notify the client of an error here; they will
 578                  * discover the problem at the SSL layer and should
 579                  * revert to unencrypted communications.
 580                  */
 581                 long errval;
 582                 char error_string[128];
 583
 584                 errval = SSL_get_error(CC->ssl, retval);
 585                 syslog(LOG_ERR, "SSL_accept failed: retval=%d, errval=%ld, err=%s",
 586                         retval,
 587                         errval,
 588                         ERR_error_string(errval, error_string)
 589                 );
 590                 SSL_free(CC->ssl);
 591                 CC->ssl = NULL;
 592                 return;
 593         }
 594         BIO_set_close(CC->ssl->rbio, BIO_NOCLOSE);
 595         bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl), &alg_bits);
 596         syslog(LOG_INFO, "SSL/TLS using %s on %s (%d of %d bits)",
 597                 SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
 598                 SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
 599                 bits, alg_bits);
 600         CC->redirect_ssl = 1;
 601 }
 602
 603
 604 /*
 605  * cmd_stls() starts SSL/TLS encryption for the current session
 606  */
 607 void cmd_stls(char *params)
 608 {
 609         char ok_response[SIZ];
 610         char nosup_response[SIZ];
 611         char error_response[SIZ];
 612
 613         unbuffer_output();
 614
 615         sprintf(ok_response, "%d Begin TLS negotiation now\n", CIT_OK);
 616         sprintf(nosup_response, "%d TLS not supported here\n", ERROR + CMD_NOT_SUPPORTED);
 617         sprintf(error_response, "%d TLS negotiation error\n", ERROR + INTERNAL_ERROR);
 618
 619         CtdlStartTLS(ok_response, nosup_response, error_response);
 620 }
 621
 622
 623 /*
 624  * cmd_gtls() returns status info about the TLS connection
 625  */
 626 void cmd_gtls(char *params)
 627 {
 628         int bits, alg_bits;
 629
 630         if (!CC->ssl || !CC->redirect_ssl) {
 631                 cprintf("%d Session is not encrypted.\n", ERROR);
 632                 return;
 633         }
 634         bits =
 635             SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl),
 636                                 &alg_bits);
 637         cprintf("%d %s|%s|%d|%d\n", CIT_OK,
 638                 SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
 639                 SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
 640                 alg_bits, bits);
 641 }
 642
 643
 644 /*
 645  * endtls() shuts down the TLS connection
 646  *
 647  * WARNING:  This may make your session vulnerable to a known plaintext
 648  * attack in the current implmentation.
 649  */
 650 void endtls(void)
 651 {
 652         if (!CC->ssl) {
 653                 CC->redirect_ssl = 0;
 654                 return;
 655         }
 656
 657         syslog(LOG_INFO, "Ending SSL/TLS");
 658         SSL_shutdown(CC->ssl);
 659         SSL_free(CC->ssl);
 660         CC->ssl = NULL;
 661         CC->redirect_ssl = 0;
 662 }
 663
 664
 665 /*
 666  * ssl_lock() callback for OpenSSL mutex locks
 667  */
 668 void ssl_lock(int mode, int n, const char *file, int line)
 669 {
 670         if (mode & CRYPTO_LOCK)
 671         {
 672                 pthread_mutex_lock(SSLCritters[n]);
 673         }
 674         else {
 675                 pthread_mutex_unlock(SSLCritters[n]);
 676         }
 677 }
 678 #endif                          /* HAVE_OPENSSL */