citadel/modules/crypto/serv_crypto.c

   1 /*
   2  * Copyright (c) 1987-2009 by the citadel.org team
   3  *
   4  *  This program is free software; you can redistribute it and/or modify
   5  *  it under the terms of the GNU General Public License as published by
   6  *  the Free Software Foundation; either version 3 of the License, or
   7  *  (at your option) any later version.
   8  *
   9  *  This program is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *  GNU General Public License for more details.
  13  *
  14  *  You should have received a copy of the GNU General Public License
  15  *  along with this program; if not, write to the Free Software
  16  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  */
  18
  19 #include <string.h>
  20 #include <unistd.h>
  21 #include <sys/stat.h>
  22 #include <sys/types.h>
  23 #include "sysdep.h"
  24
  25 #ifdef HAVE_OPENSSL
  26 #include <openssl/ssl.h>
  27 #include <openssl/err.h>
  28 #include <openssl/rand.h>
  29 #endif
  30
  31 #if TIME_WITH_SYS_TIME
  32 # include <sys/time.h>
  33 # include <time.h>
  34 #else
  35 # if HAVE_SYS_TIME_H
  36 #  include <sys/time.h>
  37 # else
  38 #  include <time.h>
  39 # endif
  40 #endif
  41
  42 #ifdef HAVE_PTHREAD_H
  43 #include <pthread.h>
  44 #endif
  45
  46 #ifdef HAVE_SYS_SELECT_H
  47 #include <sys/select.h>
  48 #endif
  49
  50 #include <stdio.h>
  51 #include <libcitadel.h>
  52 #include "server.h"
  53 #include "serv_crypto.h"
  54 #include "sysdep_decls.h"
  55 #include "citadel.h"
  56 #include "config.h"
  57
  58
  59 #include "ctdl_module.h"
  60 /* TODO: should we use the standard module init stuff to start this? */
  61 /* TODO: should we register an event handler to call destruct_ssl? */
  62
  63 #ifdef HAVE_OPENSSL
  64 SSL_CTX *ssl_ctx;               /* SSL context */
  65 pthread_mutex_t **SSLCritters;  /* Things needing locking */
  66
  67 static unsigned long id_callback(void)
  68 {
  69         return (unsigned long) pthread_self();
  70 }
  71
  72 void destruct_ssl(void)
  73 {
  74         int a;
  75         for (a = 0; a < CRYPTO_num_locks(); a++)
  76                 free(SSLCritters[a]);
  77         free (SSLCritters);
  78 }
  79
  80 void init_ssl(void)
  81 {
  82         const SSL_METHOD *ssl_method;
  83         DH *dh;
  84         RSA *rsa=NULL;
  85         X509_REQ *req = NULL;
  86         X509 *cer = NULL;
  87         EVP_PKEY *pk = NULL;
  88         EVP_PKEY *req_pkey = NULL;
  89         X509_NAME *name = NULL;
  90         FILE *fp;
  91
  92         if (!access(EGD_POOL, F_OK))
  93                 RAND_egd(EGD_POOL);
  94
  95         if (!RAND_status()) {
  96                 syslog(LOG_CRIT,
  97                         "PRNG not adequately seeded, won't do SSL/TLS\n");
  98                 return;
  99         }
 100         SSLCritters =
 101             malloc(CRYPTO_num_locks() * sizeof(pthread_mutex_t *));
 102         if (!SSLCritters) {
 103                 syslog(LOG_EMERG, "citserver: can't allocate memory!!\n");
 104                 /* Nothing's been initialized, just die */
 105                 exit(1);
 106         } else {
 107                 int a;
 108
 109                 for (a = 0; a < CRYPTO_num_locks(); a++) {
 110                         SSLCritters[a] = malloc(sizeof(pthread_mutex_t));
 111                         if (!SSLCritters[a]) {
 112                                 syslog(LOG_EMERG,
 113                                         "citserver: can't allocate memory!!\n");
 114                                 /* Nothing's been initialized, just die */
 115                                 exit(1);
 116                         }
 117                         pthread_mutex_init(SSLCritters[a], NULL);
 118                 }
 119         }
 120
 121         /*
 122          * Initialize SSL transport layer
 123          */
 124         SSL_library_init();
 125         SSL_load_error_strings();
 126         ssl_method = SSLv23_server_method();
 127         if (!(ssl_ctx = SSL_CTX_new(ssl_method))) {
 128                 syslog(LOG_CRIT, "SSL_CTX_new failed: %s\n",
 129                         ERR_reason_error_string(ERR_get_error()));
 130                 return;
 131         }
 132         if (!(SSL_CTX_set_cipher_list(ssl_ctx, CIT_CIPHERS))) {
 133                 syslog(LOG_CRIT, "SSL: No ciphers available\n");
 134                 SSL_CTX_free(ssl_ctx);
 135                 ssl_ctx = NULL;
 136                 return;
 137         }
 138 #if 0
 139 #if SSLEAY_VERSION_NUMBER >= 0x00906000L
 140         SSL_CTX_set_mode(ssl_ctx, SSL_CTX_get_mode(ssl_ctx) |
 141                          SSL_MODE_AUTO_RETRY);
 142 #endif
 143 #endif
 144
 145         CRYPTO_set_locking_callback(ssl_lock);
 146         CRYPTO_set_id_callback(id_callback);
 147
 148         /* Load DH parameters into the context */
 149         dh = DH_new();
 150         if (!dh) {
 151                 syslog(LOG_CRIT, "init_ssl() can't allocate a DH object: %s\n",
 152                         ERR_reason_error_string(ERR_get_error()));
 153                 SSL_CTX_free(ssl_ctx);
 154                 ssl_ctx = NULL;
 155                 return;
 156         }
 157         if (!(BN_hex2bn(&(dh->p), DH_P))) {
 158                 syslog(LOG_CRIT, "init_ssl() can't assign DH_P: %s\n",
 159                         ERR_reason_error_string(ERR_get_error()));
 160                 SSL_CTX_free(ssl_ctx);
 161                 ssl_ctx = NULL;
 162                 return;
 163         }
 164         if (!(BN_hex2bn(&(dh->g), DH_G))) {
 165                 syslog(LOG_CRIT, "init_ssl() can't assign DH_G: %s\n",
 166                         ERR_reason_error_string(ERR_get_error()));
 167                 SSL_CTX_free(ssl_ctx);
 168                 ssl_ctx = NULL;
 169                 return;
 170         }
 171         dh->length = DH_L;
 172         SSL_CTX_set_tmp_dh(ssl_ctx, dh);
 173         DH_free(dh);
 174
 175         /* Get our certificates in order.
 176          * First, create the key/cert directory if it's not there already...
 177          */
 178         mkdir(ctdl_key_dir, 0700);
 179
 180         /*
 181          * Generate a key pair if we don't have one.
 182          */
 183         if (access(file_crpt_file_key, R_OK) != 0) {
 184                 syslog(LOG_INFO, "Generating RSA key pair.\n");
 185                 rsa = RSA_generate_key(1024,    /* modulus size */
 186                                         65537,  /* exponent */
 187                                         NULL,   /* no callback */
 188                                         NULL);  /* no callback */
 189                 if (rsa == NULL) {
 190                         syslog(LOG_CRIT, "Key generation failed: %s\n",
 191                                 ERR_reason_error_string(ERR_get_error()));
 192                 }
 193                 if (rsa != NULL) {
 194                         fp = fopen(file_crpt_file_key, "w");
 195                         if (fp != NULL) {
 196                                 chmod(file_crpt_file_key, 0600);
 197                                 if (PEM_write_RSAPrivateKey(fp, /* the file */
 198                                                         rsa,    /* the key */
 199                                                         NULL,   /* no enc */
 200                                                         NULL,   /* no passphr */
 201                                                         0,      /* no passphr */
 202                                                         NULL,   /* no callbk */
 203                                                         NULL    /* no callbk */
 204                                 ) != 1) {
 205                                         syslog(LOG_CRIT, "Cannot write key: %s\n",
 206                                                 ERR_reason_error_string(ERR_get_error()));
 207                                         unlink(file_crpt_file_key);
 208                                 }
 209                                 fclose(fp);
 210                         }
 211                         RSA_free(rsa);
 212                 }
 213         }
 214
 215         /*
 216          * If there is no certificate file on disk, we will be generating a self-signed certificate
 217          * in the next step.  Therefore, if we have neither a CSR nor a certificate, generate
 218          * the CSR in this step so that the next step may commence.
 219          */
 220         if ( (access(file_crpt_file_cer, R_OK) != 0) && (access(file_crpt_file_csr, R_OK) != 0) ) {
 221                 syslog(LOG_INFO, "Generating a certificate signing request.\n");
 222
 223                 /*
 224                  * Read our key from the file.  No, we don't just keep this
 225                  * in memory from the above key-generation function, because
 226                  * there is the possibility that the key was already on disk
 227                  * and we didn't just generate it now.
 228                  */
 229                 fp = fopen(file_crpt_file_key, "r");
 230                 if (fp) {
 231                         rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 232                         fclose(fp);
 233                 }
 234
 235                 if (rsa) {
 236
 237                         /* Create a public key from the private key */
 238                         if (pk=EVP_PKEY_new(), pk != NULL) {
 239                                 EVP_PKEY_assign_RSA(pk, rsa);
 240                                 if (req = X509_REQ_new(), req != NULL) {
 241
 242                                         /* Set the public key */
 243                                         X509_REQ_set_pubkey(req, pk);
 244                                         X509_REQ_set_version(req, 0L);
 245
 246                                         name = X509_REQ_get_subject_name(req);
 247
 248                                         /* Tell it who we are */
 249
 250                                         /*
 251                                         X509_NAME_add_entry_by_txt(name, "C",
 252                                                 MBSTRING_ASC, "US", -1, -1, 0);
 253
 254                                         X509_NAME_add_entry_by_txt(name, "ST",
 255                                                 MBSTRING_ASC, "New York", -1, -1, 0);
 256
 257                                         X509_NAME_add_entry_by_txt(name, "L",
 258                                                 MBSTRING_ASC, "Mount Kisco", -1, -1, 0);
 259                                         */
 260
 261                                         X509_NAME_add_entry_by_txt(name, "O",
 262                                                                    MBSTRING_ASC,
 263                                                                    (unsigned char*) config.c_humannode,
 264                                                                    -1, -1, 0);
 265
 266                                         X509_NAME_add_entry_by_txt(name, "OU",
 267                                                                    MBSTRING_ASC,
 268                                                                    (unsigned const char*)"Citadel server",
 269                                                                    -1, -1, 0);
 270
 271                                         /* X509_NAME_add_entry_by_txt(name, "CN",
 272                                                 MBSTRING_ASC, config.c_fqdn, -1, -1, 0);
 273                                         */
 274
 275                                         X509_NAME_add_entry_by_txt(name,
 276                                                                    "CN",
 277                                                                    MBSTRING_ASC,
 278                                                                    (const unsigned char *)"*", -1, -1, 0);
 279
 280                                         X509_REQ_set_subject_name(req, name);
 281
 282                                         /* Sign the CSR */
 283                                         if (!X509_REQ_sign(req, pk, EVP_md5())) {
 284                                                 syslog(LOG_CRIT, "X509_REQ_sign(): error\n");
 285                                         }
 286                                         else {
 287                                                 /* Write it to disk. */
 288                                                 fp = fopen(file_crpt_file_csr, "w");
 289                                                 if (fp != NULL) {
 290                                                         chmod(file_crpt_file_csr, 0600);
 291                                                         PEM_write_X509_REQ(fp, req);
 292                                                         fclose(fp);
 293                                                 }
 294                                         }
 295
 296                                         X509_REQ_free(req);
 297                                 }
 298                         }
 299
 300                         RSA_free(rsa);
 301                 }
 302
 303                 else {
 304                         syslog(LOG_CRIT, "Unable to read private key.\n");
 305                 }
 306         }
 307
 308
 309
 310         /*
 311          * Generate a self-signed certificate if we don't have one.
 312          */
 313         if (access(file_crpt_file_cer, R_OK) != 0) {
 314                 syslog(LOG_INFO, "Generating a self-signed certificate.\n");
 315
 316                 /* Same deal as before: always read the key from disk because
 317                  * it may or may not have just been generated.
 318                  */
 319                 fp = fopen(file_crpt_file_key, "r");
 320                 if (fp) {
 321                         rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 322                         fclose(fp);
 323                 }
 324
 325                 /* This also holds true for the CSR. */
 326                 req = NULL;
 327                 cer = NULL;
 328                 pk = NULL;
 329                 if (rsa) {
 330                         if (pk=EVP_PKEY_new(), pk != NULL) {
 331                                 EVP_PKEY_assign_RSA(pk, rsa);
 332                         }
 333
 334                         fp = fopen(file_crpt_file_csr, "r");
 335                         if (fp) {
 336                                 req = PEM_read_X509_REQ(fp, NULL, NULL, NULL);
 337                                 fclose(fp);
 338                         }
 339
 340                         if (req) {
 341                                 if (cer = X509_new(), cer != NULL) {
 342
 343                                         ASN1_INTEGER_set(X509_get_serialNumber(cer), 0);
 344                                         X509_set_issuer_name(cer, req->req_info->subject);
 345                                         X509_set_subject_name(cer, req->req_info->subject);
 346                                         X509_gmtime_adj(X509_get_notBefore(cer),0);
 347                                         X509_gmtime_adj(X509_get_notAfter(cer),(long)60*60*24*SIGN_DAYS);
 348                                         req_pkey = X509_REQ_get_pubkey(req);
 349                                         X509_set_pubkey(cer, req_pkey);
 350                                         EVP_PKEY_free(req_pkey);
 351
 352                                         /* Sign the cert */
 353                                         if (!X509_sign(cer, pk, EVP_md5())) {
 354                                                 syslog(LOG_CRIT, "X509_sign(): error\n");
 355                                         }
 356                                         else {
 357                                                 /* Write it to disk. */
 358                                                 fp = fopen(file_crpt_file_cer, "w");
 359                                                 if (fp != NULL) {
 360                                                         chmod(file_crpt_file_cer, 0600);
 361                                                         PEM_write_X509(fp, cer);
 362                                                         fclose(fp);
 363                                                 }
 364                                         }
 365                                         X509_free(cer);
 366                                 }
 367                         }
 368
 369                         RSA_free(rsa);
 370                 }
 371         }
 372
 373
 374         /*
 375          * Now try to bind to the key and certificate.
 376          */
 377         SSL_CTX_use_certificate_chain_file(ssl_ctx, file_crpt_file_cer);
 378         SSL_CTX_use_PrivateKey_file(ssl_ctx, file_crpt_file_key, SSL_FILETYPE_PEM);
 379         if ( !SSL_CTX_check_private_key(ssl_ctx) ) {
 380                 syslog(LOG_CRIT, "Cannot install certificate: %s\n",
 381                                 ERR_reason_error_string(ERR_get_error()));
 382         }
 383
 384         /* Finally let the server know we're here */
 385         CtdlRegisterProtoHook(cmd_stls, "STLS", "Start SSL/TLS session");
 386         CtdlRegisterProtoHook(cmd_gtls, "GTLS",
 387                               "Get SSL/TLS session status");
 388         CtdlRegisterSessionHook(endtls, EVT_STOP);
 389 }
 390
 391
 392 /*
 393  * client_write_ssl() Send binary data to the client encrypted.
 394  */
 395 void client_write_ssl(const char *buf, int nbytes)
 396 {
 397         int retval;
 398         int nremain;
 399         char junk[1];
 400
 401         nremain = nbytes;
 402
 403         while (nremain > 0) {
 404                 if (SSL_want_write(CC->ssl)) {
 405                         if ((SSL_read(CC->ssl, junk, 0)) < 1) {
 406                                 syslog(LOG_DEBUG, "SSL_read in client_write: %s\n", ERR_reason_error_string(ERR_get_error()));
 407                         }
 408                 }
 409                 retval =
 410                     SSL_write(CC->ssl, &buf[nbytes - nremain], nremain);
 411                 if (retval < 1) {
 412                         long errval;
 413
 414                         errval = SSL_get_error(CC->ssl, retval);
 415                         if (errval == SSL_ERROR_WANT_READ ||
 416                             errval == SSL_ERROR_WANT_WRITE) {
 417                                 sleep(1);
 418                                 continue;
 419                         }
 420                         syslog(LOG_DEBUG, "SSL_write got error %ld, ret %d\n", errval, retval);
 421                         if (retval == -1)
 422                                 syslog(LOG_DEBUG, "errno is %d\n", errno);
 423                         endtls();
 424                         client_write(&buf[nbytes - nremain], nremain);
 425                         return;
 426                 }
 427                 nremain -= retval;
 428         }
 429 }
 430
 431
 432 /*
 433  * read data from the encrypted layer.
 434  */
 435 int client_read_sslbuffer(StrBuf *buf, int timeout)
 436 {
 437         char sbuf[16384]; /* OpenSSL communicates in 16k blocks, so let's speak its native tongue. */
 438         int rlen;
 439         char junk[1];
 440         SSL *pssl = CC->ssl;
 441
 442         if (pssl == NULL) return(-1);
 443
 444         while (1) {
 445                 if (SSL_want_read(pssl)) {
 446                         if ((SSL_write(pssl, junk, 0)) < 1) {
 447                                 syslog(LOG_DEBUG, "SSL_write in client_read\n");
 448                         }
 449                 }
 450                 rlen = SSL_read(pssl, sbuf, sizeof(sbuf));
 451                 if (rlen < 1) {
 452                         long errval;
 453
 454                         errval = SSL_get_error(pssl, rlen);
 455                         if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
 456                                 sleep(1);
 457                                 continue;
 458                         }
 459                         syslog(LOG_DEBUG, "SSL_read got error %ld\n", errval);
 460                         endtls();
 461                         return (-1);
 462                 }
 463                 StrBufAppendBufPlain(buf, sbuf, rlen, 0);
 464                 return rlen;
 465         }
 466         return (0);
 467 }
 468
 469 int client_readline_sslbuffer(StrBuf *Line, StrBuf *IOBuf, const char **Pos, int timeout)
 470 {
 471         CitContext *CCC = CC;
 472         const char *pos = NULL;
 473         const char *pLF;
 474         int len, rlen;
 475         int nSuccessLess = 0;
 476         const char *pch = NULL;
 477
 478         if ((Line == NULL) ||
 479             (Pos == NULL) ||
 480             (IOBuf == NULL))
 481         {
 482                 if (Pos != NULL)
 483                         *Pos = NULL;
 484 //              *Error = ErrRBLF_PreConditionFailed;
 485                 return -1;
 486         }
 487
 488         pos = *Pos;
 489         if ((StrLength(IOBuf) > 0) &&
 490             (pos != NULL) &&
 491             (pos < ChrPtr(IOBuf) + StrLength(IOBuf)))
 492         {
 493                 pch = pos;
 494                 pch = strchr(pch, '\n');
 495
 496                 if (pch == NULL) {
 497                         StrBufAppendBufPlain(Line, pos,
 498                                              StrLength(IOBuf) - (pos - ChrPtr(IOBuf)), 0);
 499                         FlushStrBuf(IOBuf);
 500                         pos = *Pos = NULL;
 501                 }
 502                 else {
 503                         int n = 0;
 504                         if ((pch > ChrPtr(IOBuf)) &&
 505                             (*(pch - 1) == '\r')) {
 506                                 n = 1;
 507                         }
 508                         StrBufAppendBufPlain(Line, pos,
 509                                              (pch - pos - n), 0);
 510
 511                         if (StrLength(IOBuf) <= (pch - ChrPtr(IOBuf) + 1)) {
 512                                 FlushStrBuf(IOBuf);
 513                                 pos = *Pos = NULL;
 514                         }
 515                         else
 516                                 *Pos = pch + 1;
 517                         return StrLength(Line);
 518                 }
 519         }
 520
 521         pLF = NULL;
 522         while ((nSuccessLess < timeout) &&
 523                (pLF == NULL) &&
 524                (CCC->ssl != NULL)) {
 525
 526                 rlen = client_read_sslbuffer(IOBuf, timeout);
 527                 if (rlen < 1) {
 528 //                      *Error = strerror(errno);
 529 //                      close(*fd);
 530 //                      *fd = -1;
 531                         return -1;
 532                 }
 533                 else if (rlen > 0) {
 534                         pLF = strchr(ChrPtr(IOBuf), '\n');
 535                 }
 536         }
 537         *Pos = NULL;
 538         if (pLF != NULL) {
 539                 pos = ChrPtr(IOBuf);
 540                 len = pLF - pos;
 541                 if (len > 0 && (*(pLF - 1) == '\r') )
 542                         len --;
 543                 StrBufAppendBufPlain(Line, pos, len, 0);
 544                 if (pLF + 1 >= ChrPtr(IOBuf) + StrLength(IOBuf))
 545                 {
 546                         FlushStrBuf(IOBuf);
 547                 }
 548                 else
 549                         *Pos = pLF + 1;
 550                 return StrLength(Line);
 551         }
 552 //      *Error = ErrRBLF_NotEnoughSentFromServer;
 553         return -1;
 554 }
 555
 556
 557
 558 int client_read_sslblob(StrBuf *Target, long bytes, int timeout)
 559 {
 560         long baselen;
 561         long RemainRead;
 562         int retval = 0;
 563         CitContext *CCC = CC;
 564
 565         baselen = StrLength(Target);
 566
 567         if (StrLength(CCC->RecvBuf.Buf) > 0)
 568         {
 569                 long RemainLen;
 570                 long TotalLen;
 571                 const char *pchs;
 572
 573                 if (CCC->RecvBuf.ReadWritePointer == NULL)
 574                         CCC->RecvBuf.ReadWritePointer = ChrPtr(CCC->RecvBuf.Buf);
 575                 pchs = ChrPtr(CCC->RecvBuf.Buf);
 576                 TotalLen = StrLength(CCC->RecvBuf.Buf);
 577                 RemainLen = TotalLen - (pchs - CCC->RecvBuf.ReadWritePointer);
 578                 if (RemainLen > bytes)
 579                         RemainLen = bytes;
 580                 if (RemainLen > 0)
 581                 {
 582                         StrBufAppendBufPlain(Target,
 583                                              CCC->RecvBuf.ReadWritePointer,
 584                                              RemainLen, 0);
 585                         CCC->RecvBuf.ReadWritePointer += RemainLen;
 586                 }
 587                 if ((ChrPtr(CCC->RecvBuf.Buf) + StrLength(CCC->RecvBuf.Buf)) <= CCC->RecvBuf.ReadWritePointer)
 588                 {
 589                         CCC->RecvBuf.ReadWritePointer = NULL;
 590                         FlushStrBuf(CCC->RecvBuf.Buf);
 591                 }
 592         }
 593
 594         if (StrLength(Target) >= bytes + baselen)
 595                 return 1;
 596
 597         CCC->RecvBuf.ReadWritePointer = NULL;
 598
 599         while ((StrLength(Target) < bytes + baselen) &&
 600                (retval >= 0))
 601         {
 602                 retval = client_read_sslbuffer(CCC->RecvBuf.Buf, timeout);
 603                 if (retval >= 0) {
 604                         RemainRead = bytes - (StrLength (Target) - baselen);
 605                         if (RemainRead < StrLength(CCC->RecvBuf.Buf))
 606                         {
 607                                 StrBufAppendBufPlain(
 608                                         Target,
 609                                         ChrPtr(CCC->RecvBuf.Buf),
 610                                         RemainRead, 0);
 611                                 CCC->RecvBuf.ReadWritePointer = ChrPtr(CCC->RecvBuf.Buf) + RemainRead;
 612                                 break;
 613                         }
 614                         StrBufAppendBuf(Target, CCC->RecvBuf.Buf, 0); /* todo: Buf > bytes? */
 615                         FlushStrBuf(CCC->RecvBuf.Buf);
 616                 }
 617                 else
 618                 {
 619                         FlushStrBuf(CCC->RecvBuf.Buf);
 620                         return -1;
 621
 622                 }
 623         }
 624         return 1;
 625 }
 626
 627
 628 /*
 629  * CtdlStartTLS() starts SSL/TLS encryption for the current session.  It
 630  * must be supplied with pre-generated strings for responses of "ok," "no
 631  * support for TLS," and "error" so that we can use this in any protocol.
 632  */
 633 void CtdlStartTLS(char *ok_response, char *nosup_response,
 634                         char *error_response) {
 635
 636         int retval, bits, alg_bits;
 637
 638         if (!ssl_ctx) {
 639                 syslog(LOG_CRIT, "SSL failed: no ssl_ctx exists?\n");
 640                 if (nosup_response != NULL) cprintf("%s", nosup_response);
 641                 return;
 642         }
 643         if (!(CC->ssl = SSL_new(ssl_ctx))) {
 644                 syslog(LOG_CRIT, "SSL_new failed: %s\n",
 645                                 ERR_reason_error_string(ERR_get_error()));
 646                 if (error_response != NULL) cprintf("%s", error_response);
 647                 return;
 648         }
 649         if (!(SSL_set_fd(CC->ssl, CC->client_socket))) {
 650                 syslog(LOG_CRIT, "SSL_set_fd failed: %s\n",
 651                         ERR_reason_error_string(ERR_get_error()));
 652                 SSL_free(CC->ssl);
 653                 CC->ssl = NULL;
 654                 if (error_response != NULL) cprintf("%s", error_response);
 655                 return;
 656         }
 657         if (ok_response != NULL) cprintf("%s", ok_response);
 658         retval = SSL_accept(CC->ssl);
 659         if (retval < 1) {
 660                 /*
 661                  * Can't notify the client of an error here; they will
 662                  * discover the problem at the SSL layer and should
 663                  * revert to unencrypted communications.
 664                  */
 665                 long errval;
 666                 char error_string[128];
 667
 668                 errval = SSL_get_error(CC->ssl, retval);
 669                 syslog(LOG_CRIT, "SSL_accept failed: retval=%d, errval=%ld, err=%s\n",
 670                         retval,
 671                         errval,
 672                         ERR_error_string(errval, error_string)
 673                 );
 674                 SSL_free(CC->ssl);
 675                 CC->ssl = NULL;
 676                 return;
 677         }
 678         BIO_set_close(CC->ssl->rbio, BIO_NOCLOSE);
 679         bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl), &alg_bits);
 680         syslog(LOG_INFO, "SSL/TLS using %s on %s (%d of %d bits)\n",
 681                 SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
 682                 SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
 683                 bits, alg_bits);
 684         CC->redirect_ssl = 1;
 685 }
 686
 687
 688 /*
 689  * cmd_stls() starts SSL/TLS encryption for the current session
 690  */
 691 void cmd_stls(char *params)
 692 {
 693         char ok_response[SIZ];
 694         char nosup_response[SIZ];
 695         char error_response[SIZ];
 696
 697         unbuffer_output();
 698
 699         sprintf(ok_response,
 700                 "%d Begin TLS negotiation now\n",
 701                 CIT_OK);
 702         sprintf(nosup_response,
 703                 "%d TLS not supported here\n",
 704                 ERROR + CMD_NOT_SUPPORTED);
 705         sprintf(error_response,
 706                 "%d TLS negotiation error\n",
 707                 ERROR + INTERNAL_ERROR);
 708
 709         CtdlStartTLS(ok_response, nosup_response, error_response);
 710 }
 711
 712
 713 /*
 714  * cmd_gtls() returns status info about the TLS connection
 715  */
 716 void cmd_gtls(char *params)
 717 {
 718         int bits, alg_bits;
 719
 720         if (!CC->ssl || !CC->redirect_ssl) {
 721                 cprintf("%d Session is not encrypted.\n", ERROR);
 722                 return;
 723         }
 724         bits =
 725             SSL_CIPHER_get_bits(SSL_get_current_cipher(CC->ssl),
 726                                 &alg_bits);
 727         cprintf("%d %s|%s|%d|%d\n", CIT_OK,
 728                 SSL_CIPHER_get_version(SSL_get_current_cipher(CC->ssl)),
 729                 SSL_CIPHER_get_name(SSL_get_current_cipher(CC->ssl)),
 730                 alg_bits, bits);
 731 }
 732
 733
 734 /*
 735  * endtls() shuts down the TLS connection
 736  *
 737  * WARNING:  This may make your session vulnerable to a known plaintext
 738  * attack in the current implmentation.
 739  */
 740 void endtls(void)
 741 {
 742         if (!CC->ssl) {
 743                 CC->redirect_ssl = 0;
 744                 return;
 745         }
 746
 747         syslog(LOG_INFO, "Ending SSL/TLS\n");
 748         SSL_shutdown(CC->ssl);
 749         SSL_free(CC->ssl);
 750         CC->ssl = NULL;
 751         CC->redirect_ssl = 0;
 752 }
 753
 754
 755 /*
 756  * ssl_lock() callback for OpenSSL mutex locks
 757  */
 758 void ssl_lock(int mode, int n, const char *file, int line)
 759 {
 760         if (mode & CRYPTO_LOCK)
 761                 pthread_mutex_lock(SSLCritters[n]);
 762         else
 763                 pthread_mutex_unlock(SSLCritters[n]);
 764 }
 765 #endif                          /* HAVE_OPENSSL */