openssl-support.diff

   1 Casey Marshall wrote:
   2
   3 I've been hacking together a way to use rsync with OpenSSL, and have
   4 attached my current patch against a recent CVS tree. The details of
   5 this implementation are:
   6
   7   1. The SSL code is added as a "layer" that is forked into its own
   8      process.
   9
  10   2. An SSL connection is established by the client issuing the
  11      command:
  12
  13        #starttls
  14
  15      And, if the daemon allows SSL, it replies with
  16
  17        @RSYNCD: starttls
  18
  19      At which point both sides begin negotiating the SSL connection.
  20      Servers that can't or don't want to use SSL just treat it as a
  21      normal unknown command.
  22
  23   3. The SSL code is meant to be unobtrusive, and when this patch is
  24      applied the program may still be built with no SSL code.
  25
  26   4. There are a number of details not implemented.
  27
  28 All warnings apply; I don't do C programming all that often, so I
  29 can't say if I've left any cleanup/compatibility errors in the code.
  30
  31 To use this patch, run these commands for a successful build:
  32
  33     patch -p1 <patches/openssl-support.diff
  34     ./prepare-source
  35     ./configure
  36     make
  37
  38 --- old/Makefile.in
  39 +++ new/Makefile.in
  40 @@ -39,7 +39,7 @@ OBJS3=progress.o pipe.o
  41  DAEMON_OBJ = params.o loadparm.o clientserver.o access.o connection.o authenticate.o
  42  popt_OBJS=popt/findme.o  popt/popt.o  popt/poptconfig.o \
  43         popt/popthelp.o popt/poptparse.o
  44 -OBJS=$(OBJS1) $(OBJS2) $(OBJS3) $(DAEMON_OBJ) $(LIBOBJ) $(ZLIBOBJ) @BUILD_POPT@
  45 +OBJS=$(OBJS1) $(OBJS2) $(OBJS3) $(DAEMON_OBJ) $(LIBOBJ) $(ZLIBOBJ) @BUILD_POPT@ @SSL_OBJS@
  46
  47  TLS_OBJ = tls.o syscall.o lib/compat.o lib/snprintf.o lib/permstring.o lib/sysxattrs.o @BUILD_POPT@
  48
  49 --- old/cleanup.c
  50 +++ new/cleanup.c
  51 @@ -25,6 +25,9 @@
  52  extern int am_server;
  53  extern int am_daemon;
  54  extern int io_error;
  55 +#ifdef HAVE_OPENSSL
  56 +extern int use_ssl;
  57 +#endif
  58  extern int keep_partial;
  59  extern int log_got_error;
  60  extern char *partial_dir;
  61 @@ -116,6 +119,14 @@ NORETURN void _exit_cleanup(int code, co
  62                                 code, file, line);
  63                 }
  64
  65 +#ifdef HAVE_OPENSSL
  66 +               /* FALLTHROUGH */
  67 +#include "case_N.h"
  68 +
  69 +               if (use_ssl)
  70 +                       end_tls();
  71 +#endif
  72 +
  73                 /* FALLTHROUGH */
  74  #include "case_N.h"
  75
  76 --- old/clientserver.c
  77 +++ new/clientserver.c
  78 @@ -29,6 +29,9 @@ extern int am_sender;
  79  extern int am_server;
  80  extern int am_daemon;
  81  extern int am_root;
  82 +#ifdef HAVE_OPENSSL
  83 +extern int use_ssl;
  84 +#endif
  85  extern int rsync_port;
  86  extern int ignore_errors;
  87  extern int kluge_around_eof;
  88 @@ -106,8 +109,18 @@ int start_socket_client(char *host, char
  89         set_socket_options(fd, sockopts);
  90
  91         ret = start_inband_exchange(user, path, fd, fd, argc);
  92 +       if (ret)
  93 +               return ret;
  94
  95 -       return ret ? ret : client_run(fd, fd, -1, argc, argv);
  96 +#ifdef HAVE_OPENSSL
  97 +       if (use_ssl) {
  98 +               int f_in = get_tls_rfd();
  99 +               int f_out = get_tls_wfd();
 100 +               return client_run(f_in, f_out, -1, argc, argv);
 101 +       }
 102 +#endif
 103 +
 104 +       return client_run(fd, fd, -1, argc, argv);
 105  }
 106
 107  int start_inband_exchange(const char *user, char *path, int f_in, int f_out,
 108 @@ -168,6 +181,33 @@ int start_inband_exchange(const char *us
 109         if (verbose > 1)
 110                 print_child_argv(sargs);
 111
 112 +#ifdef HAVE_OPENSSL
 113 +       if (use_ssl) {
 114 +               io_printf(f_out, "#starttls\n");
 115 +               while (1) {
 116 +                       if (!read_line(f_in, line, sizeof(line)-1)) {
 117 +                               rprintf(FERROR, "rsync: did not receive reply to #starttls\n");
 118 +                               return -1;
 119 +                       }
 120 +                       if (strncmp(line, "@ERROR", 6) == 0) {
 121 +                               rprintf(FERROR, "%s\n", line);
 122 +                               return -1;
 123 +                       }
 124 +                       if (strcmp(line, "@RSYNCD: starttls") == 0) {
 125 +                               break;
 126 +                       }
 127 +                       rprintf(FINFO, "%s\n", line);
 128 +               }
 129 +               if (start_tls(f_in, f_out)) {
 130 +                       rprintf(FERROR, "rsync: error during SSL handshake: %s\n",
 131 +                               get_ssl_error());
 132 +                       return -1;
 133 +               }
 134 +               f_in = get_tls_rfd();
 135 +               f_out = get_tls_wfd();
 136 +       }
 137 +#endif
 138 +
 139         p = strchr(path,'/');
 140         if (p) *p = 0;
 141         io_printf(f_out, "%s\n", path);
 142 @@ -196,6 +236,10 @@ int start_inband_exchange(const char *us
 143                          * server to terminate the listing of modules.
 144                          * We don't want to go on and transfer
 145                          * anything; just exit. */
 146 +#ifdef HAVE_OPENSSL
 147 +                       if (use_ssl)
 148 +                               end_tls();
 149 +#endif
 150                         exit(0);
 151                 }
 152
 153 @@ -203,6 +247,10 @@ int start_inband_exchange(const char *us
 154                         rprintf(FERROR, "%s\n", line);
 155                         /* This is always fatal; the server will now
 156                          * close the socket. */
 157 +#ifdef HAVE_OPENSSL
 158 +                       if (use_ssl)
 159 +                               end_tls();
 160 +#endif
 161                         return -1;
 162                 }
 163
 164 @@ -789,6 +837,9 @@ int start_daemon(int f_in, int f_out)
 165         if (protocol_version > remote_protocol)
 166                 protocol_version = remote_protocol;
 167
 168 +#ifdef HAVE_OPENSSL
 169 +retry:
 170 +#endif
 171         line[0] = 0;
 172         if (!read_line(f_in, line, sizeof line - 1))
 173                 return -1;
 174 @@ -800,6 +851,20 @@ int start_daemon(int f_in, int f_out)
 175                 return -1;
 176         }
 177
 178 +#ifdef HAVE_OPENSSL
 179 +       if (use_ssl && strcmp(line, "#starttls") == 0) {
 180 +               io_printf(f_out, "@RSYNCD: starttls\n");
 181 +               if (start_tls(f_in, f_out)) {
 182 +                       rprintf(FLOG, "SSL connection failed: %s\n",
 183 +                               get_ssl_error());
 184 +                       return -1;
 185 +               }
 186 +               f_in = get_tls_rfd();
 187 +               f_out = get_tls_wfd();
 188 +               goto retry;
 189 +       }
 190 +#endif
 191 +
 192         if (*line == '#') {
 193                 /* it's some sort of command that I don't understand */
 194                 io_printf(f_out, "@ERROR: Unknown command '%s'\n", line);
 195 --- old/configure.in
 196 +++ new/configure.in
 197 @@ -290,6 +290,21 @@ if test x"$enable_locale" != x"no"; then
 198         AC_DEFINE(CONFIG_LOCALE)
 199  fi
 200
 201 +AC_ARG_ENABLE(openssl,
 202 +              AC_HELP_STRING([--enable-openssl], [compile SSL support with OpenSSL.]))
 203 +
 204 +if test "x$enable_openssl" != xno
 205 +then
 206 +       have_ssl=yes
 207 +       AC_CHECK_LIB(ssl, SSL_library_init, , [have_ssl=no])
 208 +       if test "x$have_ssl" = xyes
 209 +       then
 210 +               AC_DEFINE(HAVE_OPENSSL, 1, [true if you want to use SSL.])
 211 +               SSL_OBJS=ssl.o
 212 +               AC_SUBST(SSL_OBJS)
 213 +       fi
 214 +fi
 215 +
 216  AC_MSG_CHECKING([whether to call shutdown on all sockets])
 217  case $host_os in
 218         *cygwin* ) AC_MSG_RESULT(yes)
 219 --- old/options.c
 220 +++ new/options.c
 221 @@ -174,6 +174,14 @@ int logfile_format_has_o_or_i = 0;
 222  int always_checksum = 0;
 223  int list_only = 0;
 224
 225 +#ifdef HAVE_OPENSSL
 226 +int use_ssl = 0;
 227 +char *ssl_cert_path = NULL;
 228 +char *ssl_key_path = NULL;
 229 +char *ssl_key_passwd = NULL;
 230 +char *ssl_ca_path = NULL;
 231 +#endif
 232 +
 233  #define MAX_BATCH_NAME_LEN 256 /* Must be less than MAXPATHLEN-13 */
 234  char *batch_name = NULL;
 235
 236 @@ -212,6 +220,7 @@ static void print_rsync_version(enum log
 237         char const *links = "no ";
 238         char const *iconv = "no ";
 239         char const *ipv6 = "no ";
 240 +       char const *ssl = "no ";
 241         STRUCT_STAT *dumstat;
 242
 243  #if SUBPROTOCOL_VERSION != 0
 244 @@ -241,6 +250,9 @@ static void print_rsync_version(enum log
 245  #ifdef ICONV_OPTION
 246         iconv = "";
 247  #endif
 248 +#ifdef HAVE_OPENSSL
 249 +       ssl = "";
 250 +#endif
 251
 252         rprintf(f, "%s  version %s  protocol version %d%s\n",
 253                 RSYNC_NAME, RSYNC_VERSION, PROTOCOL_VERSION, subprotocol);
 254 @@ -254,8 +266,8 @@ static void print_rsync_version(enum log
 255                 (int)(sizeof (int64) * 8));
 256         rprintf(f, "    %ssocketpairs, %shardlinks, %ssymlinks, %sIPv6, batchfiles, %sinplace,\n",
 257                 got_socketpair, hardlinks, links, ipv6, have_inplace);
 258 -       rprintf(f, "    %sappend, %sACLs, %sxattrs, %siconv\n",
 259 -               have_inplace, acls, xattrs, iconv);
 260 +       rprintf(f, "    %sappend, %sACLs, %sxattrs, %siconv, %sSSL\n",
 261 +               have_inplace, acls, xattrs, iconv, ssl);
 262
 263  #ifdef MAINTAINER_MODE
 264         rprintf(f, "Panic Action: \"%s\"\n", get_panic_action());
 265 @@ -415,6 +427,13 @@ void usage(enum logcode F)
 266    rprintf(F," -4, --ipv4                  prefer IPv4\n");
 267    rprintf(F," -6, --ipv6                  prefer IPv6\n");
 268  #endif
 269 +#ifdef HAVE_OPENSSL
 270 +  rprintf(F,"     --ssl                   allow socket connections to use SSL\n");
 271 +  rprintf(F,"     --ssl-cert=FILE         path to daemon's SSL certificate\n");
 272 +  rprintf(F,"     --ssl-key=FILE          path to daemon's SSL private key\n");
 273 +  rprintf(F,"     --ssl-key-passwd=PASS   password for PEM-encoded private key\n");
 274 +  rprintf(F,"     --ssl-ca-certs=FILE     path to trusted CA certificates\n");
 275 +#endif
 276    rprintf(F,"     --version               print version number\n");
 277    rprintf(F,"(-h) --help                  show this help (-h works with no other options)\n");
 278
 279 @@ -428,7 +447,7 @@ enum {OPT_VERSION = 1000, OPT_DAEMON, OP
 280        OPT_FILTER, OPT_COMPARE_DEST, OPT_COPY_DEST, OPT_LINK_DEST, OPT_HELP,
 281        OPT_INCLUDE, OPT_INCLUDE_FROM, OPT_MODIFY_WINDOW, OPT_MIN_SIZE, OPT_CHMOD,
 282        OPT_READ_BATCH, OPT_WRITE_BATCH, OPT_ONLY_WRITE_BATCH, OPT_MAX_SIZE,
 283 -      OPT_NO_D,
 284 +      OPT_NO_D, OPT_USE_SSL,
 285        OPT_SERVER, OPT_REFUSED_BASE = 9000};
 286
 287  static struct poptOption long_options[] = {
 288 @@ -590,6 +609,13 @@ static struct poptOption long_options[]
 289    {"checksum-seed",    0,  POPT_ARG_INT,    &checksum_seed, 0, 0, 0 },
 290    {"server",           0,  POPT_ARG_NONE,   0, OPT_SERVER, 0, 0 },
 291    {"sender",           0,  POPT_ARG_NONE,   0, OPT_SENDER, 0, 0 },
 292 +#ifdef HAVE_OPENSSL
 293 +  {"ssl",              0,  POPT_ARG_NONE,   0, OPT_USE_SSL, 0, 0},
 294 +  {"ssl-cert",         0,  POPT_ARG_STRING, &ssl_cert_path, OPT_USE_SSL, 0, 0},
 295 +  {"ssl-key",          0,  POPT_ARG_STRING, &ssl_key_path, OPT_USE_SSL, 0, 0},
 296 +  {"ssl-key-passwd",   0,  POPT_ARG_STRING, &ssl_key_passwd, OPT_USE_SSL, 0, 0},
 297 +  {"ssl-ca-certs",     0,  POPT_ARG_STRING, &ssl_ca_path, OPT_USE_SSL, 0, 0},
 298 +#endif
 299    /* All the following options switch us into daemon-mode option-parsing. */
 300    {"config",           0,  POPT_ARG_STRING, 0, OPT_DAEMON, 0, 0 },
 301    {"daemon",           0,  POPT_ARG_NONE,   0, OPT_DAEMON, 0, 0 },
 302 @@ -617,6 +643,13 @@ static void daemon_usage(enum logcode F)
 303    rprintf(F," -4, --ipv4                  prefer IPv4\n");
 304    rprintf(F," -6, --ipv6                  prefer IPv6\n");
 305  #endif
 306 +#ifdef HAVE_OPENSSL
 307 +  rprintf(F,"     --ssl                   allow socket connections to use SSL\n");
 308 +  rprintf(F,"     --ssl-cert=FILE         path to daemon's SSL certificate\n");
 309 +  rprintf(F,"     --ssl-key=FILE          path to daemon's SSL private key\n");
 310 +  rprintf(F,"     --ssl-key-passwd=PASS   password for PEM-encoded private key\n");
 311 +  rprintf(F,"     --ssl-ca-certs=FILE     path to trusted CA certificates\n");
 312 +#endif
 313    rprintf(F,"     --help                  show this help screen\n");
 314
 315    rprintf(F,"\n");
 316 @@ -643,6 +676,13 @@ static struct poptOption long_daemon_opt
 317    {"protocol",         0,  POPT_ARG_INT,    &protocol_version, 0, 0, 0 },
 318    {"server",           0,  POPT_ARG_NONE,   &am_server, 0, 0, 0 },
 319    {"temp-dir",        'T', POPT_ARG_STRING, &tmpdir, 0, 0, 0 },
 320 +#ifdef HAVE_OPENSSL
 321 +  {"ssl",              0,  POPT_ARG_NONE,   0, OPT_USE_SSL, 0, 0},
 322 +  {"ssl-cert",         0,  POPT_ARG_STRING, &ssl_cert_path, OPT_USE_SSL, 0, 0},
 323 +  {"ssl-key",          0,  POPT_ARG_STRING, &ssl_key_path, OPT_USE_SSL, 0, 0},
 324 +  {"ssl-key-passwd",   0,  POPT_ARG_STRING, &ssl_key_passwd, OPT_USE_SSL, 0, 0},
 325 +  {"ssl-ca-certs",     0,  POPT_ARG_STRING, &ssl_ca_path, OPT_USE_SSL, 0, 0},
 326 +#endif
 327    {"verbose",         'v', POPT_ARG_NONE,   0, 'v', 0, 0 },
 328    {"no-verbose",       0,  POPT_ARG_VAL,    &verbose, 0, 0, 0 },
 329    {"no-v",             0,  POPT_ARG_VAL,    &verbose, 0, 0, 0 },
 330 @@ -913,6 +953,12 @@ int parse_arguments(int *argc, const cha
 331                                         verbose++;
 332                                         break;
 333
 334 +#ifdef HAVE_OPENSSL
 335 +                               case OPT_USE_SSL:
 336 +                                       use_ssl = 1;
 337 +                                       break;
 338 +#endif
 339 +
 340                                 default:
 341                                         rprintf(FERROR,
 342                                             "rsync: %s: %s (in daemon mode)\n",
 343 @@ -936,6 +982,17 @@ int parse_arguments(int *argc, const cha
 344                                 exit_cleanup(RERR_SYNTAX);
 345                         }
 346
 347 +#ifdef HAVE_OPENSSL
 348 +                       if (use_ssl) {
 349 +                               if (init_tls()) {
 350 +                                       snprintf(err_buf, sizeof(err_buf),
 351 +                                                "Openssl error: %s\n",
 352 +                                                get_ssl_error());
 353 +                                       return 0;
 354 +                               }
 355 +                       }
 356 +#endif
 357 +
 358                         *argv = poptGetArgs(pc);
 359                         *argc = count_args(*argv);
 360                         am_starting_up = 0;
 361 @@ -1180,6 +1237,12 @@ int parse_arguments(int *argc, const cha
 362                         return 0;
 363  #endif
 364
 365 +#ifdef HAVE_OPENSSL
 366 +               case OPT_USE_SSL:
 367 +                       use_ssl = 1;
 368 +                       break;
 369 +#endif
 370 +
 371                 default:
 372                         /* A large opt value means that set_refuse_options()
 373                          * turned this option off. */
 374 @@ -1475,6 +1538,17 @@ int parse_arguments(int *argc, const cha
 375         if (delay_updates && !partial_dir)
 376                 partial_dir = tmp_partialdir;
 377
 378 +#ifdef HAVE_OPENSSL
 379 +       if (use_ssl) {
 380 +               if (init_tls()) {
 381 +                       snprintf(err_buf, sizeof(err_buf),
 382 +                                "Openssl error: %s\n",
 383 +                                get_ssl_error());
 384 +                       return 0;
 385 +               }
 386 +       }
 387 +#endif
 388 +
 389         if (inplace) {
 390  #ifdef HAVE_FTRUNCATE
 391                 if (partial_dir) {
 392 @@ -1928,10 +2002,27 @@ char *check_for_hostspec(char *s, char *
 393         char *p;
 394         int not_host;
 395         int hostlen;
 396 +       int url_prefix_len = sizeof URL_PREFIX - 1;
 397
 398 -       if (port_ptr && strncasecmp(URL_PREFIX, s, strlen(URL_PREFIX)) == 0) {
 399 +       if (!port_ptr)
 400 +               url_prefix_len = 0;
 401 +       else if (strncasecmp(URL_PREFIX, s, url_prefix_len) != 0) {
 402 +#ifdef HAVE_OPENSSL
 403 +               url_prefix_len = sizeof SSL_URL_PREFIX - 1;
 404 +               if (strncasecmp(SSL_URL_PREFIX, s, url_prefix_len) != 0)
 405 +                       url_prefix_len = 0;
 406 +               else {
 407 +                       if (!use_ssl)
 408 +                               init_tls();
 409 +                       use_ssl = 1;
 410 +               }
 411 +#else
 412 +               url_prefix_len = 0;
 413 +#endif
 414 +       }
 415 +       if (url_prefix_len) {
 416                 char *path;
 417 -               s += strlen(URL_PREFIX);
 418 +               s += url_prefix_len;
 419                 if ((p = strchr(s, '/')) != NULL) {
 420                         hostlen = p - s;
 421                         path = p + 1;
 422 --- old/rsync.h
 423 +++ new/rsync.h
 424 @@ -31,6 +31,7 @@
 425
 426  #define DEFAULT_LOCK_FILE "/var/run/rsyncd.lock"
 427  #define URL_PREFIX "rsync://"
 428 +#define SSL_URL_PREFIX "rsyncs://"
 429
 430  #define BACKUP_SUFFIX "~"
 431
 432 @@ -488,6 +489,11 @@ enum msgcode {
 433  # define SIZEOF_INT64 SIZEOF_OFF_T
 434  #endif
 435
 436 +#ifdef HAVE_OPENSSL
 437 +#include <openssl/ssl.h>
 438 +#include <openssl/err.h>
 439 +#endif
 440 +
 441  /* Starting from protocol version 26, we always use 64-bit
 442   * ino_t and dev_t internally, even if this platform does not
 443   * allow files to have 64-bit inums.  That's because the
 444 --- old/ssl.c
 445 +++ new/ssl.c
 446 @@ -0,0 +1,370 @@
 447 +/* -*- c-file-style: "linux" -*-
 448 + * ssl.c: operations for negotiating SSL rsync connections.
 449 + *
 450 + * Copyright (C) 2003  Casey Marshall <rsdio@metastatic.org>
 451 + *
 452 + * This program is free software; you can redistribute it and/or modify
 453 + * it under the terms of the GNU General Public License as published by
 454 + * the Free Software Foundation; either version 2 of the License, or
 455 + * (at your option) any later version.
 456 + *
 457 + * This program is distributed in the hope that it will be useful,
 458 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
 459 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 460 + * GNU General Public License for more details.
 461 + *
 462 + * You should have received a copy of the GNU General Public License
 463 + * along with this program; if not, write to the Free Software
 464 + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 465 + */
 466 +
 467 +#include "rsync.h"
 468 +
 469 +#ifdef HAVE_SYS_SELECT_H
 470 +#include <sys/select.h>
 471 +#else
 472 +#include <sys/time.h>
 473 +#include <sys/types.h>
 474 +#include <unistd.h>
 475 +#endif
 476 +#include <string.h>
 477 +
 478 +#define BUF_SIZE 1024
 479 +
 480 +extern int verbose;
 481 +extern int am_daemon;
 482 +extern int am_server;
 483 +
 484 +extern char *ssl_cert_path;
 485 +extern char *ssl_key_path;
 486 +extern char *ssl_key_passwd;
 487 +extern char *ssl_ca_path;
 488 +
 489 +static SSL_CTX *ssl_ctx;
 490 +static SSL *ssl;
 491 +static int tls_read[2] = { -1, -1 };
 492 +static int tls_write[2] = { -1, -1 };
 493 +static int ssl_running;
 494 +static int ssl_pid = -1;
 495 +
 496 +#ifdef HAVE_SIGACTION
 497 +static struct sigaction sigact;
 498 +#endif
 499 +
 500 +/**
 501 + * A non-interactive callback to be passed to SSL_CTX_set_default_password_cb,
 502 + * which merely copies the value of ssl_key_passwd into buf. This is
 503 + * used for when the private key password is supplied via an option.
 504 + */
 505 +static int default_password_cb(char *buf, int n, UNUSED(int f), UNUSED(void *u))
 506 +{
 507 +       if (ssl_key_passwd == NULL || n < (int)strlen(ssl_key_passwd))
 508 +               return 0;
 509 +       strncpy(buf, ssl_key_passwd, n-1);
 510 +       return strlen(ssl_key_passwd);
 511 +}
 512 +
 513 +/**
 514 + * If verbose, this method traces the status of the SSL handshake.
 515 + */
 516 +static void info_callback(const SSL *ssl, int cb, int val)
 517 +{
 518 +       char buf[128];
 519 +       char *cbs;
 520 +
 521 +       switch (cb) {
 522 +       case SSL_CB_LOOP:
 523 +               cbs = "SSL_CB_LOOP";
 524 +               break;
 525 +       case SSL_CB_EXIT:
 526 +               cbs = "SSL_CB_EXIT";
 527 +               break;
 528 +       case SSL_CB_READ:
 529 +               cbs = "SSL_CB_READ";
 530 +               break;
 531 +       case SSL_CB_WRITE:
 532 +               cbs = "SSL_CB_WRITE";
 533 +               break;
 534 +       case SSL_CB_ALERT:
 535 +               cbs = "SSL_CB_ALERT";
 536 +               break;
 537 +       case SSL_CB_READ_ALERT:
 538 +               cbs = "SSL_CB_READ_ALERT";
 539 +               break;
 540 +       case SSL_CB_WRITE_ALERT:
 541 +               cbs = "SSL_CB_WRITE_ALERT";
 542 +               break;
 543 +       case SSL_CB_ACCEPT_LOOP:
 544 +               cbs = "SSL_CB_ACCEPT_LOOP";
 545 +               break;
 546 +       case SSL_CB_ACCEPT_EXIT:
 547 +               cbs = "SSL_CB_ACCEPT_EXIT";
 548 +               break;
 549 +       case SSL_CB_CONNECT_LOOP:
 550 +               cbs = "SSL_CB_CONNECT_LOOP";
 551 +               break;
 552 +       case SSL_CB_CONNECT_EXIT:
 553 +               cbs = "SSL_CB_CONNECT_EXIT";
 554 +               break;
 555 +       case SSL_CB_HANDSHAKE_START:
 556 +               cbs = "SSL_CB_HANDSHAKE_START";
 557 +               break;
 558 +       case SSL_CB_HANDSHAKE_DONE:
 559 +               cbs = "SSL_CB_HANDSHAKE_DONE";
 560 +               break;
 561 +       default:
 562 +               snprintf(buf, sizeof buf, "??? (%d)", cb);
 563 +               cbs = buf;
 564 +               break;
 565 +       }
 566 +       if (verbose > 2) {
 567 +               rprintf(FLOG, "SSL: info_callback(%p,%s,%d)\n", ssl, cbs, val);
 568 +               if (cb == SSL_CB_HANDSHAKE_DONE) {
 569 +                       SSL_CIPHER_description(SSL_get_current_cipher((SSL*)ssl),
 570 +                                              buf, sizeof buf);
 571 +                       rprintf(FLOG, "SSL: cipher: %s", buf);
 572 +               }
 573 +       }
 574 +}
 575 +
 576 +/**
 577 + * Initializes the SSL context for TLSv1 connections; returns zero on
 578 + * success.
 579 + */
 580 +int init_tls(void)
 581 +{
 582 +       if (ssl_ctx)
 583 +               return 0;
 584 +       SSL_library_init();
 585 +       SSL_load_error_strings();
 586 +       ssl_ctx = SSL_CTX_new(TLSv1_method());
 587 +       if (!ssl_ctx)
 588 +               return 1;
 589 +       SSL_CTX_set_info_callback(ssl_ctx, info_callback);
 590 +
 591 +       /* Sets the certificate sent to the other party. */
 592 +       if (ssl_cert_path != NULL
 593 +           && SSL_CTX_use_certificate_file(ssl_ctx, ssl_cert_path,
 594 +                                           SSL_FILETYPE_PEM) != 1)
 595 +               return 1;
 596 +       /* Set up the simple non-interactive callback if the password
 597 +        * was supplied on the command line. */
 598 +       if (ssl_key_passwd != NULL)
 599 +               SSL_CTX_set_default_passwd_cb(ssl_ctx, default_password_cb);
 600 +       /* Sets the private key that matches the public certificate. */
 601 +       if (ssl_key_path != NULL) {
 602 +               if (SSL_CTX_use_PrivateKey_file(ssl_ctx, ssl_key_path,
 603 +                                               SSL_FILETYPE_PEM) != 1)
 604 +                       return 1;
 605 +               if (SSL_CTX_check_private_key(ssl_ctx) != 1)
 606 +                       return 1;
 607 +       }
 608 +       if (ssl_ca_path != NULL
 609 +           && !SSL_CTX_load_verify_locations(ssl_ctx, ssl_ca_path, NULL))
 610 +               return 1;
 611 +
 612 +       return 0;
 613 +}
 614 +
 615 +/**
 616 + * Returns the error string for the current SSL error, if any.
 617 + */
 618 +char *get_ssl_error(void)
 619 +{
 620 +       return ERR_error_string(ERR_get_error(), NULL);
 621 +}
 622 +
 623 +/**
 624 + * Returns the input file descriptor for the SSL connection.
 625 + */
 626 +int get_tls_rfd(void)
 627 +{
 628 +       return tls_read[0];
 629 +}
 630 +
 631 +/**
 632 + * Returns the output file descriptor for the SSL connection.
 633 + */
 634 +int get_tls_wfd(void)
 635 +{
 636 +       return tls_write[1];
 637 +}
 638 +
 639 +/**
 640 + * Signal handler that ends the SSL connection.
 641 + */
 642 +static RETSIGTYPE tls_sigusr1(int UNUSED(val))
 643 +{
 644 +       if (ssl) {
 645 +               SSL_shutdown(ssl);
 646 +               SSL_free(ssl);
 647 +               ssl = NULL;
 648 +       }
 649 +       ssl_running = 0;
 650 +}
 651 +
 652 +/**
 653 + * Negotiates the TLS connection, creates a socket pair for communicating
 654 + * with the rsync process, then forks into a new process that will handle
 655 + * the communication.
 656 + *
 657 + * 0 is returned on success.
 658 + */
 659 +int start_tls(int f_in, int f_out)
 660 +{
 661 +       int tls_fd;
 662 +       int n = 0, r;
 663 +       unsigned char buf1[BUF_SIZE], buf2[BUF_SIZE];
 664 +       int avail1 = 0, avail2 = 0, write1 = 0, write2 = 0;
 665 +       fd_set rd, wd;
 666 +
 667 +       if (fd_pair(tls_read))
 668 +               return 1;
 669 +       if (fd_pair(tls_write))
 670 +               return 1;
 671 +
 672 +       set_blocking(tls_read[0]);
 673 +       set_blocking(tls_read[1]);
 674 +       set_blocking(tls_write[0]);
 675 +       set_blocking(tls_write[1]);
 676 +       set_blocking(f_in);
 677 +       set_blocking(f_out);
 678 +
 679 +       ssl_pid = do_fork();
 680 +       if (ssl_pid < 0)
 681 +               return -1;
 682 +       if (ssl_pid != 0) {
 683 +               close(tls_write[0]);
 684 +               close(tls_read[1]);
 685 +               return 0;
 686 +       }
 687 +
 688 +       SIGACTION(SIGUSR1, tls_sigusr1);
 689 +       ssl = SSL_new(ssl_ctx);
 690 +       if (!ssl)
 691 +               goto closed;
 692 +       if (am_daemon || am_server)
 693 +               SSL_set_accept_state(ssl);
 694 +       else
 695 +               SSL_set_connect_state(ssl);
 696 +       SSL_set_rfd(ssl, f_in);
 697 +       SSL_set_wfd(ssl, f_out);
 698 +
 699 +       tls_fd = SSL_get_fd(ssl);
 700 +       n = tls_write[0];
 701 +       n = MAX(tls_read[1], n);
 702 +       n = MAX(tls_fd, n) + 1;
 703 +
 704 +       ssl_running = 1;
 705 +       while (ssl_running) {
 706 +               FD_ZERO(&rd);
 707 +               FD_ZERO(&wd);
 708 +               FD_SET(tls_write[0], &rd);
 709 +               FD_SET(tls_read[1], &wd);
 710 +               FD_SET(tls_fd, &rd);
 711 +               FD_SET(tls_fd, &wd);
 712 +
 713 +               r = select(n, &rd, &wd, NULL, NULL);
 714 +
 715 +               if (r == -1 && errno == EINTR)
 716 +                       continue;
 717 +               if (FD_ISSET(tls_write[0], &rd)) {
 718 +                       r = read(tls_write[0], buf1+avail1, BUF_SIZE-avail1);
 719 +                       if (r >= 0)
 720 +                               avail1 += r;
 721 +                       else {
 722 +                               rprintf(FERROR, "pipe read error: %s\n",
 723 +                                       strerror(errno));
 724 +                               break;
 725 +                       }
 726 +               }
 727 +               if (FD_ISSET(tls_fd, &rd)) {
 728 +                       r = SSL_read(ssl, buf2+avail2, BUF_SIZE-avail2);
 729 +                       if (r > 0)
 730 +                               avail2 += r;
 731 +                       else {
 732 +                               switch (SSL_get_error(ssl, r)) {
 733 +                               case SSL_ERROR_ZERO_RETURN:
 734 +                                       goto closed;
 735 +                               case SSL_ERROR_WANT_READ:
 736 +                               case SSL_ERROR_WANT_WRITE:
 737 +                                       break;
 738 +                               case SSL_ERROR_SYSCALL:
 739 +                                       if (r == 0)
 740 +                                               rprintf(FERROR, "SSL spurious EOF\n");
 741 +                                       else
 742 +                                               rprintf(FERROR, "SSL I/O error: %s\n",
 743 +                                                       strerror(errno));
 744 +                                       goto closed;
 745 +                               case SSL_ERROR_SSL:
 746 +                                       rprintf(FERROR, "SSL: %s\n",
 747 +                                               ERR_error_string(ERR_get_error(), NULL));
 748 +                                       goto closed;
 749 +                               default:
 750 +                                       rprintf(FERROR, "unexpected ssl error %d\n", r);
 751 +                                       goto closed;
 752 +                               }
 753 +                       }
 754 +               }
 755 +               if (FD_ISSET(tls_read[1], &wd) && write2 < avail2) {
 756 +                       r = write(tls_read[1], buf2+write2, avail2-write2);
 757 +                       if (r >= 0)
 758 +                               write2 += r;
 759 +                       else {
 760 +                               rprintf(FERROR, "pipe write error: %s\n",
 761 +                                       strerror(errno));
 762 +                               break;
 763 +                       }
 764 +               }
 765 +               if (FD_ISSET(tls_fd, &wd) && write1 < avail1) {
 766 +                       r = SSL_write(ssl, buf1+write1, avail1-write1);
 767 +                       if (r > 0)
 768 +                               write1 += r;
 769 +                       else {
 770 +                               switch (SSL_get_error(ssl, r)) {
 771 +                               case SSL_ERROR_ZERO_RETURN:
 772 +                                       goto closed;
 773 +                               case SSL_ERROR_WANT_READ:
 774 +                               case SSL_ERROR_WANT_WRITE:
 775 +                                       break;
 776 +                               case SSL_ERROR_SYSCALL:
 777 +                                       if (r == 0)
 778 +                                               rprintf(FERROR, "SSL: spurious EOF\n");
 779 +                                       else
 780 +                                               rprintf(FERROR, "SSL: I/O error: %s\n",
 781 +                                                       strerror(errno));
 782 +                                       goto closed;
 783 +                               case SSL_ERROR_SSL:
 784 +                                       rprintf(FERROR, "SSL: %s\n",
 785 +                                               ERR_error_string(ERR_get_error(), NULL));
 786 +                                       goto closed;
 787 +                               default:
 788 +                                       rprintf(FERROR, "unexpected ssl error %d\n", r);
 789 +                                       goto closed;
 790 +                               }
 791 +                       }
 792 +               }
 793 +               if (avail1 == write1)
 794 +                       avail1 = write1 = 0;
 795 +               if (avail2 == write2)
 796 +                       avail2 = write2 = 0;
 797 +       }
 798 +
 799 +       /* XXX I'm pretty sure that there is a lot that I am not considering
 800 +          here. Bugs? Yes, probably. */
 801 +
 802 +       /* We're finished. */
 803 +    closed:
 804 +       close(tls_read[1]);
 805 +       close(tls_write[0]);
 806 +       exit(0);
 807 +}
 808 +
 809 +/**
 810 + * Ends the TLS connection.
 811 + */
 812 +void end_tls(void)
 813 +{
 814 +       if (ssl_pid > 0)
 815 +               kill(ssl_pid, SIGUSR1);
 816 +}