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