openssl-support.diff

   1 After applying this patch, run these commands for a successful build:
   2
   3     autoconf
   4     autoheader
   5     ./configure
   6     make proto
   7     make
   8
   9 Casey Marshall writes:
  10
  11 I've been hacking together a way to use rsync with OpenSSL, and have
  12 attached my current patch against a recent CVS tree. The details of
  13 this implementation are:
  14
  15   1. The SSL code is added as a "layer" that is forked into its own
  16      process.
  17
  18   2. An SSL connection is established by the client issuing the
  19      command:
  20
  21        #starttls
  22
  23      And, if the daemon allows SSL, it replies with
  24
  25        @RSYNCD: starttls
  26
  27      At which point both sides begin negotiating the SSL connection.
  28      Servers that can't or don't want to use SSL just treat it as a
  29      normal unknown command.
  30
  31   3. The SSL code is meant to be unobtrusive, and when this patch is
  32      applied the program may still be built with no SSL code.
  33
  34   4. There are a number of details not implemented.
  35
  36 All warnings apply; I don't do C programming all that often, so I
  37 can't say if I've left any cleanup/compatibility errors in the code.
  38
  39
  40 --- orig/Makefile.in    2006-01-14 08:14:29
  41 +++ Makefile.in 2004-10-08 20:17:06
  42 @@ -38,7 +38,7 @@ OBJS3=progress.o pipe.o
  43  DAEMON_OBJ = params.o loadparm.o clientserver.o access.o connection.o authenticate.o
  44  popt_OBJS=popt/findme.o  popt/popt.o  popt/poptconfig.o \
  45         popt/popthelp.o popt/poptparse.o
  46 -OBJS=$(OBJS1) $(OBJS2) $(OBJS3) $(DAEMON_OBJ) $(LIBOBJ) $(ZLIBOBJ) @BUILD_POPT@
  47 +OBJS=$(OBJS1) $(OBJS2) $(OBJS3) $(DAEMON_OBJ) $(LIBOBJ) $(ZLIBOBJ) @BUILD_POPT@ @SSL_OBJS@
  48
  49  TLS_OBJ = tls.o syscall.o lib/compat.o lib/snprintf.o lib/permstring.o
  50
  51 --- orig/cleanup.c      2006-01-14 08:14:29
  52 +++ cleanup.c   2005-01-10 10:43:22
  53 @@ -22,6 +22,9 @@
  54  #include "rsync.h"
  55
  56  extern int io_error;
  57 +#if HAVE_OPENSSL
  58 +extern int use_ssl;
  59 +#endif
  60  extern int keep_partial;
  61  extern int log_got_error;
  62  extern char *partial_dir;
  63 @@ -97,6 +100,11 @@ void _exit_cleanup(int code, const char
  64         signal(SIGUSR1, SIG_IGN);
  65         signal(SIGUSR2, SIG_IGN);
  66
  67 +#if HAVE_OPENSSL
  68 +       if (use_ssl)
  69 +               end_tls();
  70 +#endif
  71 +
  72         if (verbose > 3) {
  73                 rprintf(FINFO,"_exit_cleanup(code=%d, file=%s, line=%d): entered\n",
  74                         code, file, line);
  75 --- orig/clientserver.c 2006-01-14 08:14:29
  76 +++ clientserver.c      2005-04-09 17:39:57
  77 @@ -44,6 +44,9 @@ extern int io_timeout;
  78  extern int orig_umask;
  79  extern int no_detach;
  80  extern int default_af_hint;
  81 +#if HAVE_OPENSSL
  82 +extern int use_ssl;
  83 +#endif
  84  extern char *bind_address;
  85  extern struct filter_list_struct server_filter_list;
  86  extern char *config_file;
  87 @@ -99,8 +102,18 @@ int start_socket_client(char *host, char
  88                 exit_cleanup(RERR_SOCKETIO);
  89
  90         ret = start_inband_exchange(user, path, fd, fd, argc);
  91 +       if (ret)
  92 +               return ret;
  93 +
  94 +#if HAVE_OPENSSL
  95 +       if (use_ssl) {
  96 +               int f_in = get_tls_rfd();
  97 +               int f_out = get_tls_wfd();
  98 +               return client_run(f_in, f_out, -1, argc, argv);
  99 +       }
 100 +#endif
 101
 102 -       return ret ? ret : client_run(fd, fd, -1, argc, argv);
 103 +       return client_run(fd, fd, -1, argc, argv);
 104  }
 105
 106  int start_inband_exchange(char *user, char *path, int f_in, int f_out,
 107 @@ -161,6 +174,33 @@ int start_inband_exchange(char *user, ch
 108         if (verbose > 1)
 109                 print_child_argv(sargs);
 110
 111 +#if HAVE_OPENSSL
 112 +       if (use_ssl) {
 113 +               io_printf(f_out, "#starttls\n");
 114 +               while (1) {
 115 +                       if (!read_line(f_in, line, sizeof(line)-1)) {
 116 +                               rprintf(FERROR, "rsync: did not receive reply to #starttls\n");
 117 +                               return -1;
 118 +                       }
 119 +                       if (strncmp(line, "@ERROR", 6) == 0) {
 120 +                               rprintf(FERROR, "%s\n", line);
 121 +                               return -1;
 122 +                       }
 123 +                       if (strcmp(line, "@RSYNCD: starttls") == 0) {
 124 +                               break;
 125 +                       }
 126 +                       rprintf(FINFO, "%s\n", line);
 127 +               }
 128 +               if (start_tls(f_in, f_out)) {
 129 +                       rprintf(FERROR, "rsync: error during SSL handshake: %s\n",
 130 +                               get_ssl_error());
 131 +                       return -1;
 132 +               }
 133 +               f_in = get_tls_rfd();
 134 +               f_out = get_tls_wfd();
 135 +       }
 136 +#endif
 137 +
 138         p = strchr(path,'/');
 139         if (p) *p = 0;
 140         io_printf(f_out, "%s\n", path);
 141 @@ -189,6 +229,10 @@ int start_inband_exchange(char *user, ch
 142                          * server to terminate the listing of modules.
 143                          * We don't want to go on and transfer
 144                          * anything; just exit. */
 145 +#if HAVE_OPENSSL
 146 +                       if (use_ssl)
 147 +                               end_tls();
 148 +#endif
 149                         exit(0);
 150                 }
 151
 152 @@ -196,6 +240,10 @@ int start_inband_exchange(char *user, ch
 153                         rprintf(FERROR, "%s\n", line);
 154                         /* This is always fatal; the server will now
 155                          * close the socket. */
 156 +#if HAVE_OPENSSL
 157 +                       if (use_ssl)
 158 +                               end_tls();
 159 +#endif
 160                         return -1;
 161                 }
 162
 163 @@ -700,6 +748,7 @@ static void send_listing(int fd)
 164                 io_printf(fd,"@RSYNCD: EXIT\n");
 165  }
 166
 167 +
 168  /* this is called when a connection is established to a client
 169     and we want to start talking. The setup of the system is done from
 170     here */
 171 @@ -749,6 +798,9 @@ int start_daemon(int f_in, int f_out)
 172         if (protocol_version > remote_protocol)
 173                 protocol_version = remote_protocol;
 174
 175 +#if HAVE_OPENSSL
 176 +retry:
 177 +#endif
 178         line[0] = 0;
 179         if (!read_line(f_in, line, sizeof line - 1))
 180                 return -1;
 181 @@ -758,6 +810,20 @@ int start_daemon(int f_in, int f_out)
 182                 return -1;
 183         }
 184
 185 +#if HAVE_OPENSSL
 186 +       if (use_ssl && strcmp(line, "#starttls") == 0) {
 187 +               io_printf(f_out, "@RSYNCD: starttls\n");
 188 +               if (start_tls(f_in, f_out)) {
 189 +                       rprintf(FLOG, "SSL connection failed: %s\n",
 190 +                               get_ssl_error());
 191 +                       return -1;
 192 +               }
 193 +               f_in = get_tls_rfd();
 194 +               f_out = get_tls_wfd();
 195 +               goto retry;
 196 +       }
 197 +#endif
 198 +
 199         if (*line == '#') {
 200                 /* it's some sort of command that I don't understand */
 201                 io_printf(f_out, "@ERROR: Unknown command '%s'\n", line);
 202 --- orig/configure.in   2006-01-15 14:52:33
 203 +++ configure.in        2004-07-03 20:22:28
 204 @@ -282,6 +282,21 @@ if test x"$enable_locale" != x"no"; then
 205         AC_DEFINE(CONFIG_LOCALE)
 206  fi
 207
 208 +AC_ARG_ENABLE(openssl,
 209 +              AC_HELP_STRING([--enable-openssl], [compile SSL support with OpenSSL.]))
 210 +
 211 +if test "x$enable_openssl" != xno
 212 +then
 213 +       have_ssl=yes
 214 +       AC_CHECK_LIB(ssl, SSL_library_init, , [have_ssl=no])
 215 +       if test "x$have_ssl" = xyes
 216 +       then
 217 +               AC_DEFINE(HAVE_OPENSSL, 1, [true if you want to use SSL.])
 218 +               SSL_OBJS=ssl.o
 219 +               AC_SUBST(SSL_OBJS)
 220 +       fi
 221 +fi
 222 +
 223  AC_MSG_CHECKING([whether to call shutdown on all sockets])
 224  case $host_os in
 225         *cygwin* ) AC_MSG_RESULT(yes)
 226 --- orig/options.c      2006-01-21 21:02:30
 227 +++ options.c   2006-01-21 21:13:11
 228 @@ -163,6 +163,14 @@ int log_format_has_o_or_i = 0;
 229  int always_checksum = 0;
 230  int list_only = 0;
 231
 232 +#if HAVE_OPENSSL
 233 +int use_ssl = 0;
 234 +char *ssl_cert_path = NULL;
 235 +char *ssl_key_path = NULL;
 236 +char *ssl_key_passwd = NULL;
 237 +char *ssl_ca_path = NULL;
 238 +#endif
 239 +
 240  #define MAX_BATCH_NAME_LEN 256 /* Must be less than MAXPATHLEN-13 */
 241  char *batch_name = NULL;
 242
 243 @@ -191,6 +199,7 @@ static void print_rsync_version(enum log
 244         char const *hardlinks = "no ";
 245         char const *links = "no ";
 246         char const *ipv6 = "no ";
 247 +       char const *ssl = "no ";
 248         STRUCT_STAT *dumstat;
 249
 250  #ifdef HAVE_SOCKETPAIR
 251 @@ -213,6 +222,10 @@ static void print_rsync_version(enum log
 252         ipv6 = "";
 253  #endif
 254
 255 +#if HAVE_OPENSSL
 256 +       ssl = "";
 257 +#endif
 258 +
 259         rprintf(f, "%s  version %s  protocol version %d\n",
 260                 RSYNC_NAME, RSYNC_VERSION, PROTOCOL_VERSION);
 261         rprintf(f, "Copyright (C) 1996-2006 by Wayne Davison, Andrew Tridgell, and others\n");
 262 @@ -225,10 +238,10 @@ static void print_rsync_version(enum log
 263         /* Note that this field may not have type ino_t.  It depends
 264          * on the complicated interaction between largefile feature
 265          * macros. */
 266 -       rprintf(f, "              %sinplace, %sIPv6, %d-bit system inums, %d-bit internal inums\n",
 267 +       rprintf(f, "              %sinplace, %sIPv6, %d-bit system inums, %d-bit internal inums, %sssl\n",
 268                 have_inplace, ipv6,
 269                 (int) (sizeof dumstat->st_ino * 8),
 270 -               (int) (sizeof (int64) * 8));
 271 +               (int) (sizeof (int64) * 8), ssl);
 272  #ifdef MAINTAINER_MODE
 273         rprintf(f, "              panic action: \"%s\"\n",
 274                 get_panic_action());
 275 @@ -361,6 +374,13 @@ void usage(enum logcode F)
 276    rprintf(F," -4, --ipv4                  prefer IPv4\n");
 277    rprintf(F," -6, --ipv6                  prefer IPv6\n");
 278  #endif
 279 +#if HAVE_OPENSSL
 280 +  rprintf(F,"     --ssl                   allow socket connections to use SSL\n");
 281 +  rprintf(F,"     --ssl-cert=FILE         path to daemon's SSL certificate\n");
 282 +  rprintf(F,"     --ssl-key=FILE          path to daemon's SSL private key\n");
 283 +  rprintf(F,"     --ssl-key-passwd=PASS   password for PEM-encoded private key\n");
 284 +  rprintf(F,"     --ssl-ca-certs=FILE     path to trusted CA certificates\n");
 285 +#endif
 286    rprintf(F,"     --version               print version number\n");
 287    rprintf(F,"     --help                  show this help screen\n");
 288
 289 @@ -373,6 +393,7 @@ enum {OPT_VERSION = 1000, OPT_DAEMON, OP
 290        OPT_FILTER, OPT_COMPARE_DEST, OPT_COPY_DEST, OPT_LINK_DEST, OPT_HELP,
 291        OPT_INCLUDE, OPT_INCLUDE_FROM, OPT_MODIFY_WINDOW, OPT_MIN_SIZE, OPT_CHMOD,
 292        OPT_READ_BATCH, OPT_WRITE_BATCH, OPT_ONLY_WRITE_BATCH, OPT_MAX_SIZE,
 293 +      OPT_USE_SSL,
 294        OPT_SERVER, OPT_REFUSED_BASE = 9000};
 295
 296  static struct poptOption long_options[] = {
 297 @@ -501,6 +522,13 @@ static struct poptOption long_options[]
 298    {"checksum-seed",    0,  POPT_ARG_INT,    &checksum_seed, 0, 0, 0 },
 299    {"server",           0,  POPT_ARG_NONE,   0, OPT_SERVER, 0, 0 },
 300    {"sender",           0,  POPT_ARG_NONE,   0, OPT_SENDER, 0, 0 },
 301 +#if HAVE_OPENSSL
 302 +  {"ssl",              0,  POPT_ARG_NONE,   0, OPT_USE_SSL, 0, 0},
 303 +  {"ssl-cert",         0,  POPT_ARG_STRING, &ssl_cert_path, OPT_USE_SSL, 0, 0},
 304 +  {"ssl-key",          0,  POPT_ARG_STRING, &ssl_key_path, OPT_USE_SSL, 0, 0},
 305 +  {"ssl-key-passwd",   0,  POPT_ARG_STRING, &ssl_key_passwd, OPT_USE_SSL, 0, 0},
 306 +  {"ssl-ca-certs",     0,  POPT_ARG_STRING, &ssl_ca_path, OPT_USE_SSL, 0, 0},
 307 +#endif
 308    /* All the following options switch us into daemon-mode option-parsing. */
 309    {"config",           0,  POPT_ARG_STRING, 0, OPT_DAEMON, 0, 0 },
 310    {"daemon",           0,  POPT_ARG_NONE,   0, OPT_DAEMON, 0, 0 },
 311 @@ -1027,6 +1055,12 @@ int parse_arguments(int *argc, const cha
 312                         usage(FINFO);
 313                         exit_cleanup(0);
 314
 315 +               case OPT_USE_SSL:
 316 +#if HAVE_OPENSSL
 317 +                       use_ssl = 1;
 318 +#endif
 319 +                       break;
 320 +
 321                 default:
 322                         /* A large opt value means that set_refuse_options()
 323                          * turned this option off. */
 324 @@ -1305,6 +1339,17 @@ int parse_arguments(int *argc, const cha
 325         if (delay_updates && !partial_dir)
 326                 partial_dir = partialdir_for_delayupdate;
 327
 328 +#if HAVE_OPENSSL
 329 +       if (use_ssl) {
 330 +               if (init_tls()) {
 331 +                       snprintf(err_buf, sizeof(err_buf),
 332 +                                "Openssl error: %s\n",
 333 +                                get_ssl_error());
 334 +                       return 0;
 335 +               }
 336 +       }
 337 +#endif
 338 +
 339         if (inplace) {
 340  #ifdef HAVE_FTRUNCATE
 341                 if (partial_dir) {
 342 @@ -1700,11 +1745,28 @@ char *check_for_hostspec(char *s, char *
 343  {
 344         char *p;
 345         int not_host;
 346 +       int url_prefix_len = sizeof URL_PREFIX - 1;
 347
 348 -       if (port_ptr && strncasecmp(URL_PREFIX, s, strlen(URL_PREFIX)) == 0) {
 349 +       if (!port_ptr)
 350 +               url_prefix_len = 0;
 351 +       else if (strncasecmp(URL_PREFIX, s, url_prefix_len) != 0) {
 352 +#if HAVE_OPENSSL
 353 +               url_prefix_len = sizeof SSL_URL_PREFIX - 1;
 354 +               if (strncasecmp(SSL_URL_PREFIX, s, url_prefix_len) != 0)
 355 +                       url_prefix_len = 0;
 356 +               else {
 357 +                       if (!use_ssl)
 358 +                               init_tls();
 359 +                       use_ssl = 1;
 360 +               }
 361 +#else
 362 +               url_prefix_len = 0;
 363 +#endif
 364 +       }
 365 +       if (url_prefix_len) {
 366                 char *path;
 367                 int hostlen;
 368 -               s += strlen(URL_PREFIX);
 369 +               s += url_prefix_len;
 370                 if ((p = strchr(s, '/')) != NULL) {
 371                         hostlen = p - s;
 372                         path = p + 1;
 373 --- orig/rsync.h        2006-01-21 21:02:30
 374 +++ rsync.h     2004-10-08 21:01:33
 375 @@ -32,6 +32,7 @@
 376
 377  #define DEFAULT_LOCK_FILE "/var/run/rsyncd.lock"
 378  #define URL_PREFIX "rsync://"
 379 +#define SSL_URL_PREFIX "rsyncs://"
 380
 381  #define BACKUP_SUFFIX "~"
 382
 383 @@ -410,6 +411,11 @@ enum msgcode {
 384  # define SIZEOF_INT64 SIZEOF_OFF_T
 385  #endif
 386
 387 +#if HAVE_OPENSSL
 388 +#include <openssl/ssl.h>
 389 +#include <openssl/err.h>
 390 +#endif
 391 +
 392  /* Starting from protocol version 26, we always use 64-bit
 393   * ino_t and dev_t internally, even if this platform does not
 394   * allow files to have 64-bit inums.  That's because the
 395 --- orig/ssl.c  2004-10-08 19:37:22
 396 +++ ssl.c       2004-10-08 19:37:22
 397 @@ -0,0 +1,366 @@
 398 +/* -*- c-file-style: "linux" -*-
 399 + * ssl.c: operations for negotiating SSL rsync connections.
 400 + *
 401 + * Copyright (C) 2003  Casey Marshall <rsdio@metastatic.org>
 402 + *
 403 + * This program is free software; you can redistribute it and/or modify
 404 + * it under the terms of the GNU General Public License as published by
 405 + * the Free Software Foundation; either version 2 of the License, or
 406 + * (at your option) any later version.
 407 + *
 408 + * This program is distributed in the hope that it will be useful,
 409 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
 410 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 411 + * GNU General Public License for more details.
 412 + *
 413 + * You should have received a copy of the GNU General Public License
 414 + * along with this program; if not, write to the Free Software
 415 + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 416 + */
 417 +
 418 +#include "rsync.h"
 419 +
 420 +#if HAVE_SYS_SELECT_H
 421 +#include <sys/select.h>
 422 +#else
 423 +#include <sys/time.h>
 424 +#include <sys/types.h>
 425 +#include <unistd.h>
 426 +#endif
 427 +#include <string.h>
 428 +
 429 +#define BUF_SIZE 1024
 430 +
 431 +extern int verbose;
 432 +extern int am_daemon;
 433 +extern int am_server;
 434 +
 435 +extern char *ssl_cert_path;
 436 +extern char *ssl_key_path;
 437 +extern char *ssl_key_passwd;
 438 +extern char *ssl_ca_path;
 439 +
 440 +static SSL_CTX *ssl_ctx;
 441 +static SSL *ssl;
 442 +static int tls_read[2] = { -1, -1 };
 443 +static int tls_write[2] = { -1, -1 };
 444 +static int ssl_running;
 445 +static int ssl_pid = -1;
 446 +
 447 +/**
 448 + * A non-interactive callback to be passed to SSL_CTX_set_default_password_cb,
 449 + * which merely copies the value of ssl_key_passwd into buf. This is
 450 + * used for when the private key password is supplied via an option.
 451 + */
 452 +static int default_password_cb(char *buf, int n, UNUSED(int f), UNUSED(void *u))
 453 +{
 454 +       if (ssl_key_passwd == NULL || n < (int)strlen(ssl_key_passwd))
 455 +               return 0;
 456 +       strncpy(buf, ssl_key_passwd, n-1);
 457 +       return strlen(ssl_key_passwd);
 458 +}
 459 +
 460 +/**
 461 + * If verbose, this method traces the status of the SSL handshake.
 462 + */
 463 +static void info_callback(const SSL *ssl, int cb, int val)
 464 +{
 465 +       char buf[128];
 466 +       char *cbs;
 467 +
 468 +       switch (cb) {
 469 +       case SSL_CB_LOOP:
 470 +               cbs = "SSL_CB_LOOP";
 471 +               break;
 472 +       case SSL_CB_EXIT:
 473 +               cbs = "SSL_CB_EXIT";
 474 +               break;
 475 +       case SSL_CB_READ:
 476 +               cbs = "SSL_CB_READ";
 477 +               break;
 478 +       case SSL_CB_WRITE:
 479 +               cbs = "SSL_CB_WRITE";
 480 +               break;
 481 +       case SSL_CB_ALERT:
 482 +               cbs = "SSL_CB_ALERT";
 483 +               break;
 484 +       case SSL_CB_READ_ALERT:
 485 +               cbs = "SSL_CB_READ_ALERT";
 486 +               break;
 487 +       case SSL_CB_WRITE_ALERT:
 488 +               cbs = "SSL_CB_WRITE_ALERT";
 489 +               break;
 490 +       case SSL_CB_ACCEPT_LOOP:
 491 +               cbs = "SSL_CB_ACCEPT_LOOP";
 492 +               break;
 493 +       case SSL_CB_ACCEPT_EXIT:
 494 +               cbs = "SSL_CB_ACCEPT_EXIT";
 495 +               break;
 496 +       case SSL_CB_CONNECT_LOOP:
 497 +               cbs = "SSL_CB_CONNECT_LOOP";
 498 +               break;
 499 +       case SSL_CB_CONNECT_EXIT:
 500 +               cbs = "SSL_CB_CONNECT_EXIT";
 501 +               break;
 502 +       case SSL_CB_HANDSHAKE_START:
 503 +               cbs = "SSL_CB_HANDSHAKE_START";
 504 +               break;
 505 +       case SSL_CB_HANDSHAKE_DONE:
 506 +               cbs = "SSL_CB_HANDSHAKE_DONE";
 507 +               break;
 508 +       default:
 509 +               snprintf(buf, sizeof buf, "??? (%d)", cb);
 510 +               cbs = buf;
 511 +               break;
 512 +       }
 513 +       if (verbose > 2) {
 514 +               rprintf(FLOG, "SSL: info_callback(%p,%s,%d)\n", ssl, cbs, val);
 515 +               if (cb == SSL_CB_HANDSHAKE_DONE) {
 516 +                       SSL_CIPHER_description(SSL_get_current_cipher((SSL*)ssl),
 517 +                                              buf, sizeof buf);
 518 +                       rprintf(FLOG, "SSL: cipher: %s", buf);
 519 +               }
 520 +       }
 521 +}
 522 +
 523 +/**
 524 + * Initializes the SSL context for TLSv1 connections; returns zero on
 525 + * success.
 526 + */
 527 +int init_tls(void)
 528 +{
 529 +       if (ssl_ctx)
 530 +               return 0;
 531 +       SSL_library_init();
 532 +       SSL_load_error_strings();
 533 +       ssl_ctx = SSL_CTX_new(TLSv1_method());
 534 +       if (!ssl_ctx)
 535 +               return 1;
 536 +       SSL_CTX_set_info_callback(ssl_ctx, info_callback);
 537 +
 538 +       /* Sets the certificate sent to the other party. */
 539 +       if (ssl_cert_path != NULL
 540 +           && SSL_CTX_use_certificate_file(ssl_ctx, ssl_cert_path,
 541 +                                           SSL_FILETYPE_PEM) != 1)
 542 +               return 1;
 543 +       /* Set up the simple non-interactive callback if the password
 544 +        * was supplied on the command line. */
 545 +       if (ssl_key_passwd != NULL)
 546 +               SSL_CTX_set_default_passwd_cb(ssl_ctx, default_password_cb);
 547 +       /* Sets the private key that matches the public certificate. */
 548 +       if (ssl_key_path != NULL) {
 549 +               if (SSL_CTX_use_PrivateKey_file(ssl_ctx, ssl_key_path,
 550 +                                               SSL_FILETYPE_PEM) != 1)
 551 +                       return 1;
 552 +               if (SSL_CTX_check_private_key(ssl_ctx) != 1)
 553 +                       return 1;
 554 +       }
 555 +       if (ssl_ca_path != NULL
 556 +           && !SSL_CTX_load_verify_locations(ssl_ctx, ssl_ca_path, NULL))
 557 +               return 1;
 558 +
 559 +       return 0;
 560 +}
 561 +
 562 +/**
 563 + * Returns the error string for the current SSL error, if any.
 564 + */
 565 +char *get_ssl_error(void)
 566 +{
 567 +       return ERR_error_string(ERR_get_error(), NULL);
 568 +}
 569 +
 570 +/**
 571 + * Returns the input file descriptor for the SSL connection.
 572 + */
 573 +int get_tls_rfd(void)
 574 +{
 575 +       return tls_read[0];
 576 +}
 577 +
 578 +/**
 579 + * Returns the output file descriptor for the SSL connection.
 580 + */
 581 +int get_tls_wfd(void)
 582 +{
 583 +       return tls_write[1];
 584 +}
 585 +
 586 +/**
 587 + * Signal handler that ends the SSL connection.
 588 + */
 589 +static RETSIGTYPE tls_sigusr1(int UNUSED(val))
 590 +{
 591 +       if (ssl) {
 592 +               SSL_shutdown(ssl);
 593 +               SSL_free(ssl);
 594 +               ssl = NULL;
 595 +       }
 596 +       ssl_running = 0;
 597 +}
 598 +
 599 +/**
 600 + * Negotiates the TLS connection, creates a socket pair for communicating
 601 + * with the rsync process, then forks into a new process that will handle
 602 + * the communication.
 603 + *
 604 + * 0 is returned on success.
 605 + */
 606 +int start_tls(int f_in, int f_out)
 607 +{
 608 +       int tls_fd;
 609 +       int n = 0, r;
 610 +       unsigned char buf1[BUF_SIZE], buf2[BUF_SIZE];
 611 +       int avail1 = 0, avail2 = 0, write1 = 0, write2 = 0;
 612 +       fd_set rd, wd;
 613 +
 614 +       if (fd_pair(tls_read))
 615 +               return 1;
 616 +       if (fd_pair(tls_write))
 617 +               return 1;
 618 +
 619 +       set_blocking(tls_read[0]);
 620 +       set_blocking(tls_read[1]);
 621 +       set_blocking(tls_write[0]);
 622 +       set_blocking(tls_write[1]);
 623 +       set_blocking(f_in);
 624 +       set_blocking(f_out);
 625 +
 626 +       ssl_pid = do_fork();
 627 +       if (ssl_pid < 0)
 628 +               return -1;
 629 +       if (ssl_pid != 0) {
 630 +               close(tls_write[0]);
 631 +               close(tls_read[1]);
 632 +               return 0;
 633 +       }
 634 +
 635 +       signal(SIGUSR1, tls_sigusr1);
 636 +       ssl = SSL_new(ssl_ctx);
 637 +       if (!ssl)
 638 +               goto closed;
 639 +       if (am_daemon || am_server)
 640 +               SSL_set_accept_state(ssl);
 641 +       else
 642 +               SSL_set_connect_state(ssl);
 643 +       SSL_set_rfd(ssl, f_in);
 644 +       SSL_set_wfd(ssl, f_out);
 645 +
 646 +       tls_fd = SSL_get_fd(ssl);
 647 +       n = tls_write[0];
 648 +       n = MAX(tls_read[1], n);
 649 +       n = MAX(tls_fd, n) + 1;
 650 +
 651 +       ssl_running = 1;
 652 +       while (ssl_running) {
 653 +               FD_ZERO(&rd);
 654 +               FD_ZERO(&wd);
 655 +               FD_SET(tls_write[0], &rd);
 656 +               FD_SET(tls_read[1], &wd);
 657 +               FD_SET(tls_fd, &rd);
 658 +               FD_SET(tls_fd, &wd);
 659 +
 660 +               r = select(n, &rd, &wd, NULL, NULL);
 661 +
 662 +               if (r == -1 && errno == EINTR)
 663 +                       continue;
 664 +               if (FD_ISSET(tls_write[0], &rd)) {
 665 +                       r = read(tls_write[0], buf1+avail1, BUF_SIZE-avail1);
 666 +                       if (r >= 0)
 667 +                               avail1 += r;
 668 +                       else {
 669 +                               rprintf(FERROR, "pipe read error: %s\n",
 670 +                                       strerror(errno));
 671 +                               break;
 672 +                       }
 673 +               }
 674 +               if (FD_ISSET(tls_fd, &rd)) {
 675 +                       r = SSL_read(ssl, buf2+avail2, BUF_SIZE-avail2);
 676 +                       if (r > 0)
 677 +                               avail2 += r;
 678 +                       else {
 679 +                               switch (SSL_get_error(ssl, r)) {
 680 +                               case SSL_ERROR_ZERO_RETURN:
 681 +                                       goto closed;
 682 +                               case SSL_ERROR_WANT_READ:
 683 +                               case SSL_ERROR_WANT_WRITE:
 684 +                                       break;
 685 +                               case SSL_ERROR_SYSCALL:
 686 +                                       if (r == 0)
 687 +                                               rprintf(FERROR, "SSL spurious EOF\n");
 688 +                                       else
 689 +                                               rprintf(FERROR, "SSL I/O error: %s\n",
 690 +                                                       strerror(errno));
 691 +                                       goto closed;
 692 +                               case SSL_ERROR_SSL:
 693 +                                       rprintf(FERROR, "SSL: %s\n",
 694 +                                               ERR_error_string(ERR_get_error(), NULL));
 695 +                                       goto closed;
 696 +                               default:
 697 +                                       rprintf(FERROR, "unexpected ssl error %d\n", r);
 698 +                                       goto closed;
 699 +                               }
 700 +                       }
 701 +               }
 702 +               if (FD_ISSET(tls_read[1], &wd) && write2 < avail2) {
 703 +                       r = write(tls_read[1], buf2+write2, avail2-write2);
 704 +                       if (r >= 0)
 705 +                               write2 += r;
 706 +                       else {
 707 +                               rprintf(FERROR, "pipe write error: %s\n",
 708 +                                       strerror(errno));
 709 +                               break;
 710 +                       }
 711 +               }
 712 +               if (FD_ISSET(tls_fd, &wd) && write1 < avail1) {
 713 +                       r = SSL_write(ssl, buf1+write1, avail1-write1);
 714 +                       if (r > 0)
 715 +                               write1 += r;
 716 +                       else {
 717 +                               switch (SSL_get_error(ssl, r)) {
 718 +                               case SSL_ERROR_ZERO_RETURN:
 719 +                                       goto closed;
 720 +                               case SSL_ERROR_WANT_READ:
 721 +                               case SSL_ERROR_WANT_WRITE:
 722 +                                       break;
 723 +                               case SSL_ERROR_SYSCALL:
 724 +                                       if (r == 0)
 725 +                                               rprintf(FERROR, "SSL: spurious EOF\n");
 726 +                                       else
 727 +                                               rprintf(FERROR, "SSL: I/O error: %s\n",
 728 +                                                       strerror(errno));
 729 +                                       goto closed;
 730 +                               case SSL_ERROR_SSL:
 731 +                                       rprintf(FERROR, "SSL: %s\n",
 732 +                                               ERR_error_string(ERR_get_error(), NULL));
 733 +                                       goto closed;
 734 +                               default:
 735 +                                       rprintf(FERROR, "unexpected ssl error %d\n", r);
 736 +                                       goto closed;
 737 +                               }
 738 +                       }
 739 +               }
 740 +               if (avail1 == write1)
 741 +                       avail1 = write1 = 0;
 742 +               if (avail2 == write2)
 743 +                       avail2 = write2 = 0;
 744 +       }
 745 +
 746 +       /* XXX I'm pretty sure that there is a lot that I am not considering
 747 +          here. Bugs? Yes, probably. */
 748 +
 749 +       /* We're finished. */
 750 +    closed:
 751 +       close(tls_read[1]);
 752 +       close(tls_write[0]);
 753 +       exit(0);
 754 +}
 755 +
 756 +/**
 757 + * Ends the TLS connection.
 758 + */
 759 +void end_tls(void)
 760 +{
 761 +       if (ssl_pid > 0)
 762 +               kill(ssl_pid, SIGUSR1);
 763 +}