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 @@ -112,8 +115,18 @@ int start_socket_client(char *host, int
  89         set_socket_options(fd, sockopts);
  90
  91         ret = start_inband_exchange(fd, fd, user, remote_argc, remote_argv);
  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  static int exchange_protocols(int f_in, int f_out, char *buf, size_t bufsiz, int am_client)
 108 @@ -244,6 +257,32 @@ int start_inband_exchange(int f_in, int
 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_old(f_in, line, sizeof line)) {
 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 +                       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 @@ -272,6 +311,10 @@ int start_inband_exchange(int f_in, int
 142                          * server to terminate the listing of modules.
 143                          * We don't want to go on and transfer
 144                          * anything; just exit. */
 145 +#ifdef HAVE_OPENSSL
 146 +                       if (use_ssl)
 147 +                               end_tls();
 148 +#endif
 149                         exit(0);
 150                 }
 151
 152 @@ -279,6 +322,10 @@ int start_inband_exchange(int f_in, int
 153                         rprintf(FERROR, "%s\n", line);
 154                         /* This is always fatal; the server will now
 155                          * close the socket. */
 156 +#ifdef HAVE_OPENSSL
 157 +                       if (use_ssl)
 158 +                               end_tls();
 159 +#endif
 160                         return -1;
 161                 }
 162
 163 @@ -807,6 +854,9 @@ int start_daemon(int f_in, int f_out)
 164         if (exchange_protocols(f_in, f_out, line, sizeof line, 0) < 0)
 165                 return -1;
 166
 167 +#ifdef HAVE_OPENSSL
 168 +retry:
 169 +#endif
 170         line[0] = 0;
 171         if (!read_line_old(f_in, line, sizeof line))
 172                 return -1;
 173 @@ -818,6 +868,20 @@ int start_daemon(int f_in, int f_out)
 174                 return -1;
 175         }
 176
 177 +#ifdef HAVE_OPENSSL
 178 +       if (use_ssl && strcmp(line, "#starttls") == 0) {
 179 +               io_printf(f_out, "@RSYNCD: starttls\n");
 180 +               if (start_tls(f_in, f_out)) {
 181 +                       rprintf(FLOG, "SSL connection failed: %s\n",
 182 +                               get_ssl_error());
 183 +                       return -1;
 184 +               }
 185 +               f_in = get_tls_rfd();
 186 +               f_out = get_tls_wfd();
 187 +               goto retry;
 188 +       }
 189 +#endif
 190 +
 191         if (*line == '#') {
 192                 /* it's some sort of command that I don't understand */
 193                 io_printf(f_out, "@ERROR: Unknown command '%s'\n", line);
 194 --- old/configure.in
 195 +++ new/configure.in
 196 @@ -290,6 +290,21 @@ if test x"$enable_locale" != x"no"; then
 197         AC_DEFINE(CONFIG_LOCALE)
 198  fi
 199
 200 +AC_ARG_ENABLE(openssl,
 201 +              AC_HELP_STRING([--enable-openssl], [compile SSL support with OpenSSL.]))
 202 +
 203 +if test "x$enable_openssl" != xno
 204 +then
 205 +       have_ssl=yes
 206 +       AC_CHECK_LIB(ssl, SSL_library_init, , [have_ssl=no])
 207 +       if test "x$have_ssl" = xyes
 208 +       then
 209 +               AC_DEFINE(HAVE_OPENSSL, 1, [true if you want to use SSL.])
 210 +               SSL_OBJS=ssl.o
 211 +               AC_SUBST(SSL_OBJS)
 212 +       fi
 213 +fi
 214 +
 215  AC_MSG_CHECKING([whether to call shutdown on all sockets])
 216  case $host_os in
 217         *cygwin* ) AC_MSG_RESULT(yes)
 218 --- old/options.c
 219 +++ new/options.c
 220 @@ -181,6 +181,14 @@ int logfile_format_has_o_or_i = 0;
 221  int always_checksum = 0;
 222  int list_only = 0;
 223
 224 +#ifdef HAVE_OPENSSL
 225 +int use_ssl = 0;
 226 +char *ssl_cert_path = NULL;
 227 +char *ssl_key_path = NULL;
 228 +char *ssl_key_passwd = NULL;
 229 +char *ssl_ca_path = NULL;
 230 +#endif
 231 +
 232  #define MAX_BATCH_NAME_LEN 256 /* Must be less than MAXPATHLEN-13 */
 233  char *batch_name = NULL;
 234
 235 @@ -220,6 +228,7 @@ static void print_rsync_version(enum log
 236         char const *links = "no ";
 237         char const *iconv = "no ";
 238         char const *ipv6 = "no ";
 239 +       char const *ssl = "no ";
 240         STRUCT_STAT *dumstat;
 241
 242  #if SUBPROTOCOL_VERSION != 0
 243 @@ -249,6 +258,9 @@ static void print_rsync_version(enum log
 244  #ifdef ICONV_OPTION
 245         iconv = "";
 246  #endif
 247 +#ifdef HAVE_OPENSSL
 248 +       ssl = "";
 249 +#endif
 250
 251         rprintf(f, "%s  version %s  protocol version %d%s\n",
 252                 RSYNC_NAME, RSYNC_VERSION, PROTOCOL_VERSION, subprotocol);
 253 @@ -262,8 +274,8 @@ static void print_rsync_version(enum log
 254                 (int)(sizeof (int64) * 8));
 255         rprintf(f, "    %ssocketpairs, %shardlinks, %ssymlinks, %sIPv6, batchfiles, %sinplace,\n",
 256                 got_socketpair, hardlinks, links, ipv6, have_inplace);
 257 -       rprintf(f, "    %sappend, %sACLs, %sxattrs, %siconv\n",
 258 -               have_inplace, acls, xattrs, iconv);
 259 +       rprintf(f, "    %sappend, %sACLs, %sxattrs, %siconv, %sSSL\n",
 260 +               have_inplace, acls, xattrs, iconv, ssl);
 261
 262  #ifdef MAINTAINER_MODE
 263         rprintf(f, "Panic Action: \"%s\"\n", get_panic_action());
 264 @@ -424,6 +436,13 @@ void usage(enum logcode F)
 265  #endif
 266    rprintf(F," -4, --ipv4                  prefer IPv4\n");
 267    rprintf(F," -6, --ipv6                  prefer IPv6\n");
 268 +#ifdef HAVE_OPENSSL
 269 +  rprintf(F,"     --ssl                   allow socket connections to use SSL\n");
 270 +  rprintf(F,"     --ssl-cert=FILE         path to daemon's SSL certificate\n");
 271 +  rprintf(F,"     --ssl-key=FILE          path to daemon's SSL private key\n");
 272 +  rprintf(F,"     --ssl-key-passwd=PASS   password for PEM-encoded private key\n");
 273 +  rprintf(F,"     --ssl-ca-certs=FILE     path to trusted CA certificates\n");
 274 +#endif
 275    rprintf(F,"     --version               print version number\n");
 276    rprintf(F,"(-h) --help                  show this help (-h works with no other options)\n");
 277
 278 @@ -437,7 +456,7 @@ enum {OPT_VERSION = 1000, OPT_DAEMON, OP
 279        OPT_FILTER, OPT_COMPARE_DEST, OPT_COPY_DEST, OPT_LINK_DEST, OPT_HELP,
 280        OPT_INCLUDE, OPT_INCLUDE_FROM, OPT_MODIFY_WINDOW, OPT_MIN_SIZE, OPT_CHMOD,
 281        OPT_READ_BATCH, OPT_WRITE_BATCH, OPT_ONLY_WRITE_BATCH, OPT_MAX_SIZE,
 282 -      OPT_NO_D, OPT_APPEND,
 283 +      OPT_NO_D, OPT_APPEND, OPT_USE_SSL,
 284        OPT_SERVER, OPT_REFUSED_BASE = 9000};
 285
 286  static struct poptOption long_options[] = {
 287 @@ -620,6 +639,13 @@ static struct poptOption long_options[]
 288    {"checksum-seed",    0,  POPT_ARG_INT,    &checksum_seed, 0, 0, 0 },
 289    {"server",           0,  POPT_ARG_NONE,   0, OPT_SERVER, 0, 0 },
 290    {"sender",           0,  POPT_ARG_NONE,   0, OPT_SENDER, 0, 0 },
 291 +#ifdef HAVE_OPENSSL
 292 +  {"ssl",              0,  POPT_ARG_NONE,   0, OPT_USE_SSL, 0, 0},
 293 +  {"ssl-cert",         0,  POPT_ARG_STRING, &ssl_cert_path, OPT_USE_SSL, 0, 0},
 294 +  {"ssl-key",          0,  POPT_ARG_STRING, &ssl_key_path, OPT_USE_SSL, 0, 0},
 295 +  {"ssl-key-passwd",   0,  POPT_ARG_STRING, &ssl_key_passwd, OPT_USE_SSL, 0, 0},
 296 +  {"ssl-ca-certs",     0,  POPT_ARG_STRING, &ssl_ca_path, OPT_USE_SSL, 0, 0},
 297 +#endif
 298    /* All the following options switch us into daemon-mode option-parsing. */
 299    {"config",           0,  POPT_ARG_STRING, 0, OPT_DAEMON, 0, 0 },
 300    {"daemon",           0,  POPT_ARG_NONE,   0, OPT_DAEMON, 0, 0 },
 301 @@ -645,6 +671,13 @@ static void daemon_usage(enum logcode F)
 302    rprintf(F," -v, --verbose               increase verbosity\n");
 303    rprintf(F," -4, --ipv4                  prefer IPv4\n");
 304    rprintf(F," -6, --ipv6                  prefer IPv6\n");
 305 +#ifdef HAVE_OPENSSL
 306 +  rprintf(F,"     --ssl                   allow socket connections to use SSL\n");
 307 +  rprintf(F,"     --ssl-cert=FILE         path to daemon's SSL certificate\n");
 308 +  rprintf(F,"     --ssl-key=FILE          path to daemon's SSL private key\n");
 309 +  rprintf(F,"     --ssl-key-passwd=PASS   password for PEM-encoded private key\n");
 310 +  rprintf(F,"     --ssl-ca-certs=FILE     path to trusted CA certificates\n");
 311 +#endif
 312    rprintf(F,"     --help                  show this help screen\n");
 313
 314    rprintf(F,"\n");
 315 @@ -669,6 +702,13 @@ static struct poptOption long_daemon_opt
 316    {"protocol",         0,  POPT_ARG_INT,    &protocol_version, 0, 0, 0 },
 317    {"server",           0,  POPT_ARG_NONE,   &am_server, 0, 0, 0 },
 318    {"temp-dir",        'T', POPT_ARG_STRING, &tmpdir, 0, 0, 0 },
 319 +#ifdef HAVE_OPENSSL
 320 +  {"ssl",              0,  POPT_ARG_NONE,   0, OPT_USE_SSL, 0, 0},
 321 +  {"ssl-cert",         0,  POPT_ARG_STRING, &ssl_cert_path, OPT_USE_SSL, 0, 0},
 322 +  {"ssl-key",          0,  POPT_ARG_STRING, &ssl_key_path, OPT_USE_SSL, 0, 0},
 323 +  {"ssl-key-passwd",   0,  POPT_ARG_STRING, &ssl_key_passwd, OPT_USE_SSL, 0, 0},
 324 +  {"ssl-ca-certs",     0,  POPT_ARG_STRING, &ssl_ca_path, OPT_USE_SSL, 0, 0},
 325 +#endif
 326    {"verbose",         'v', POPT_ARG_NONE,   0, 'v', 0, 0 },
 327    {"no-verbose",       0,  POPT_ARG_VAL,    &verbose, 0, 0, 0 },
 328    {"no-v",             0,  POPT_ARG_VAL,    &verbose, 0, 0, 0 },
 329 @@ -943,6 +983,12 @@ int parse_arguments(int *argc_p, const c
 330                                         verbose++;
 331                                         break;
 332
 333 +#ifdef HAVE_OPENSSL
 334 +                               case OPT_USE_SSL:
 335 +                                       use_ssl = 1;
 336 +                                       break;
 337 +#endif
 338 +
 339                                 default:
 340                                         rprintf(FERROR,
 341                                             "rsync: %s: %s (in daemon mode)\n",
 342 @@ -966,6 +1012,17 @@ int parse_arguments(int *argc_p, const c
 343                                 exit_cleanup(RERR_SYNTAX);
 344                         }
 345
 346 +#ifdef HAVE_OPENSSL
 347 +                       if (use_ssl) {
 348 +                               if (init_tls()) {
 349 +                                       snprintf(err_buf, sizeof(err_buf),
 350 +                                                "Openssl error: %s\n",
 351 +                                                get_ssl_error());
 352 +                                       return 0;
 353 +                               }
 354 +                       }
 355 +#endif
 356 +
 357                         *argv_p = argv = poptGetArgs(pc);
 358                         *argc_p = argc = count_args(argv);
 359                         am_starting_up = 0;
 360 @@ -1216,6 +1273,12 @@ int parse_arguments(int *argc_p, const c
 361                         return 0;
 362  #endif
 363
 364 +#ifdef HAVE_OPENSSL
 365 +               case OPT_USE_SSL:
 366 +                       use_ssl = 1;
 367 +                       break;
 368 +#endif
 369 +
 370                 default:
 371                         /* A large opt value means that set_refuse_options()
 372                          * turned this option off. */
 373 @@ -1530,6 +1593,17 @@ int parse_arguments(int *argc_p, const c
 374         if (delay_updates && !partial_dir)
 375                 partial_dir = tmp_partialdir;
 376
 377 +#ifdef HAVE_OPENSSL
 378 +       if (use_ssl) {
 379 +               if (init_tls()) {
 380 +                       snprintf(err_buf, sizeof(err_buf),
 381 +                                "Openssl error: %s\n",
 382 +                                get_ssl_error());
 383 +                       return 0;
 384 +               }
 385 +       }
 386 +#endif
 387 +
 388         if (inplace) {
 389  #ifdef HAVE_FTRUNCATE
 390                 if (partial_dir) {
 391 @@ -1997,10 +2071,27 @@ char *check_for_hostspec(char *s, char *
 392         char *p;
 393         int not_host;
 394         int hostlen;
 395 +       int url_prefix_len = sizeof URL_PREFIX - 1;
 396
 397 -       if (port_ptr && strncasecmp(URL_PREFIX, s, strlen(URL_PREFIX)) == 0) {
 398 +       if (!port_ptr)
 399 +               url_prefix_len = 0;
 400 +       else if (strncasecmp(URL_PREFIX, s, url_prefix_len) != 0) {
 401 +#ifdef HAVE_OPENSSL
 402 +               url_prefix_len = sizeof SSL_URL_PREFIX - 1;
 403 +               if (strncasecmp(SSL_URL_PREFIX, s, url_prefix_len) != 0)
 404 +                       url_prefix_len = 0;
 405 +               else {
 406 +                       if (!use_ssl)
 407 +                               init_tls();
 408 +                       use_ssl = 1;
 409 +               }
 410 +#else
 411 +               url_prefix_len = 0;
 412 +#endif
 413 +       }
 414 +       if (url_prefix_len) {
 415                 char *path;
 416 -               s += strlen(URL_PREFIX);
 417 +               s += url_prefix_len;
 418                 if ((p = strchr(s, '/')) != NULL) {
 419                         hostlen = p - s;
 420                         path = p + 1;
 421 --- old/rsync.h
 422 +++ new/rsync.h
 423 @@ -31,6 +31,7 @@
 424
 425  #define DEFAULT_LOCK_FILE "/var/run/rsyncd.lock"
 426  #define URL_PREFIX "rsync://"
 427 +#define SSL_URL_PREFIX "rsyncs://"
 428
 429  #define BACKUP_SUFFIX "~"
 430
 431 @@ -491,6 +492,11 @@ enum msgcode {
 432  # define SIZEOF_INT64 SIZEOF_OFF_T
 433  #endif
 434
 435 +#ifdef HAVE_OPENSSL
 436 +#include <openssl/ssl.h>
 437 +#include <openssl/err.h>
 438 +#endif
 439 +
 440  struct hashtable {
 441         void *nodes;
 442         int32 size, entries;
 443 --- old/ssl.c
 444 +++ new/ssl.c
 445 @@ -0,0 +1,370 @@
 446 +/* -*- c-file-style: "linux" -*-
 447 + * ssl.c: operations for negotiating SSL rsync connections.
 448 + *
 449 + * Copyright (C) 2003  Casey Marshall <rsdio@metastatic.org>
 450 + *
 451 + * This program is free software; you can redistribute it and/or modify
 452 + * it under the terms of the GNU General Public License as published by
 453 + * the Free Software Foundation; either version 2 of the License, or
 454 + * (at your option) any later version.
 455 + *
 456 + * This program is distributed in the hope that it will be useful,
 457 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
 458 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 459 + * GNU General Public License for more details.
 460 + *
 461 + * You should have received a copy of the GNU General Public License
 462 + * along with this program; if not, write to the Free Software
 463 + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 464 + */
 465 +
 466 +#include "rsync.h"
 467 +
 468 +#ifdef HAVE_SYS_SELECT_H
 469 +#include <sys/select.h>
 470 +#else
 471 +#include <sys/time.h>
 472 +#include <sys/types.h>
 473 +#include <unistd.h>
 474 +#endif
 475 +#include <string.h>
 476 +
 477 +#define BUF_SIZE 1024
 478 +
 479 +extern int verbose;
 480 +extern int am_daemon;
 481 +extern int am_server;
 482 +
 483 +extern char *ssl_cert_path;
 484 +extern char *ssl_key_path;
 485 +extern char *ssl_key_passwd;
 486 +extern char *ssl_ca_path;
 487 +
 488 +static SSL_CTX *ssl_ctx;
 489 +static SSL *ssl;
 490 +static int tls_read[2] = { -1, -1 };
 491 +static int tls_write[2] = { -1, -1 };
 492 +static int ssl_running;
 493 +static int ssl_pid = -1;
 494 +
 495 +#ifdef HAVE_SIGACTION
 496 +static struct sigaction sigact;
 497 +#endif
 498 +
 499 +/**
 500 + * A non-interactive callback to be passed to SSL_CTX_set_default_password_cb,
 501 + * which merely copies the value of ssl_key_passwd into buf. This is
 502 + * used for when the private key password is supplied via an option.
 503 + */
 504 +static int default_password_cb(char *buf, int n, UNUSED(int f), UNUSED(void *u))
 505 +{
 506 +       if (ssl_key_passwd == NULL || n < (int)strlen(ssl_key_passwd))
 507 +               return 0;
 508 +       strncpy(buf, ssl_key_passwd, n-1);
 509 +       return strlen(ssl_key_passwd);
 510 +}
 511 +
 512 +/**
 513 + * If verbose, this method traces the status of the SSL handshake.
 514 + */
 515 +static void info_callback(const SSL *ssl, int cb, int val)
 516 +{
 517 +       char buf[128];
 518 +       char *cbs;
 519 +
 520 +       switch (cb) {
 521 +       case SSL_CB_LOOP:
 522 +               cbs = "SSL_CB_LOOP";
 523 +               break;
 524 +       case SSL_CB_EXIT:
 525 +               cbs = "SSL_CB_EXIT";
 526 +               break;
 527 +       case SSL_CB_READ:
 528 +               cbs = "SSL_CB_READ";
 529 +               break;
 530 +       case SSL_CB_WRITE:
 531 +               cbs = "SSL_CB_WRITE";
 532 +               break;
 533 +       case SSL_CB_ALERT:
 534 +               cbs = "SSL_CB_ALERT";
 535 +               break;
 536 +       case SSL_CB_READ_ALERT:
 537 +               cbs = "SSL_CB_READ_ALERT";
 538 +               break;
 539 +       case SSL_CB_WRITE_ALERT:
 540 +               cbs = "SSL_CB_WRITE_ALERT";
 541 +               break;
 542 +       case SSL_CB_ACCEPT_LOOP:
 543 +               cbs = "SSL_CB_ACCEPT_LOOP";
 544 +               break;
 545 +       case SSL_CB_ACCEPT_EXIT:
 546 +               cbs = "SSL_CB_ACCEPT_EXIT";
 547 +               break;
 548 +       case SSL_CB_CONNECT_LOOP:
 549 +               cbs = "SSL_CB_CONNECT_LOOP";
 550 +               break;
 551 +       case SSL_CB_CONNECT_EXIT:
 552 +               cbs = "SSL_CB_CONNECT_EXIT";
 553 +               break;
 554 +       case SSL_CB_HANDSHAKE_START:
 555 +               cbs = "SSL_CB_HANDSHAKE_START";
 556 +               break;
 557 +       case SSL_CB_HANDSHAKE_DONE:
 558 +               cbs = "SSL_CB_HANDSHAKE_DONE";
 559 +               break;
 560 +       default:
 561 +               snprintf(buf, sizeof buf, "??? (%d)", cb);
 562 +               cbs = buf;
 563 +               break;
 564 +       }
 565 +       if (verbose > 2) {
 566 +               rprintf(FLOG, "SSL: info_callback(%p,%s,%d)\n", ssl, cbs, val);
 567 +               if (cb == SSL_CB_HANDSHAKE_DONE) {
 568 +                       SSL_CIPHER_description(SSL_get_current_cipher((SSL*)ssl),
 569 +                                              buf, sizeof buf);
 570 +                       rprintf(FLOG, "SSL: cipher: %s", buf);
 571 +               }
 572 +       }
 573 +}
 574 +
 575 +/**
 576 + * Initializes the SSL context for TLSv1 connections; returns zero on
 577 + * success.
 578 + */
 579 +int init_tls(void)
 580 +{
 581 +       if (ssl_ctx)
 582 +               return 0;
 583 +       SSL_library_init();
 584 +       SSL_load_error_strings();
 585 +       ssl_ctx = SSL_CTX_new(TLSv1_method());
 586 +       if (!ssl_ctx)
 587 +               return 1;
 588 +       SSL_CTX_set_info_callback(ssl_ctx, info_callback);
 589 +
 590 +       /* Sets the certificate sent to the other party. */
 591 +       if (ssl_cert_path != NULL
 592 +           && SSL_CTX_use_certificate_file(ssl_ctx, ssl_cert_path,
 593 +                                           SSL_FILETYPE_PEM) != 1)
 594 +               return 1;
 595 +       /* Set up the simple non-interactive callback if the password
 596 +        * was supplied on the command line. */
 597 +       if (ssl_key_passwd != NULL)
 598 +               SSL_CTX_set_default_passwd_cb(ssl_ctx, default_password_cb);
 599 +       /* Sets the private key that matches the public certificate. */
 600 +       if (ssl_key_path != NULL) {
 601 +               if (SSL_CTX_use_PrivateKey_file(ssl_ctx, ssl_key_path,
 602 +                                               SSL_FILETYPE_PEM) != 1)
 603 +                       return 1;
 604 +               if (SSL_CTX_check_private_key(ssl_ctx) != 1)
 605 +                       return 1;
 606 +       }
 607 +       if (ssl_ca_path != NULL
 608 +           && !SSL_CTX_load_verify_locations(ssl_ctx, ssl_ca_path, NULL))
 609 +               return 1;
 610 +
 611 +       return 0;
 612 +}
 613 +
 614 +/**
 615 + * Returns the error string for the current SSL error, if any.
 616 + */
 617 +char *get_ssl_error(void)
 618 +{
 619 +       return ERR_error_string(ERR_get_error(), NULL);
 620 +}
 621 +
 622 +/**
 623 + * Returns the input file descriptor for the SSL connection.
 624 + */
 625 +int get_tls_rfd(void)
 626 +{
 627 +       return tls_read[0];
 628 +}
 629 +
 630 +/**
 631 + * Returns the output file descriptor for the SSL connection.
 632 + */
 633 +int get_tls_wfd(void)
 634 +{
 635 +       return tls_write[1];
 636 +}
 637 +
 638 +/**
 639 + * Signal handler that ends the SSL connection.
 640 + */
 641 +static RETSIGTYPE tls_sigusr1(int UNUSED(val))
 642 +{
 643 +       if (ssl) {
 644 +               SSL_shutdown(ssl);
 645 +               SSL_free(ssl);
 646 +               ssl = NULL;
 647 +       }
 648 +       ssl_running = 0;
 649 +}
 650 +
 651 +/**
 652 + * Negotiates the TLS connection, creates a socket pair for communicating
 653 + * with the rsync process, then forks into a new process that will handle
 654 + * the communication.
 655 + *
 656 + * 0 is returned on success.
 657 + */
 658 +int start_tls(int f_in, int f_out)
 659 +{
 660 +       int tls_fd;
 661 +       int n = 0, r;
 662 +       unsigned char buf1[BUF_SIZE], buf2[BUF_SIZE];
 663 +       int avail1 = 0, avail2 = 0, write1 = 0, write2 = 0;
 664 +       fd_set rd, wd;
 665 +
 666 +       if (fd_pair(tls_read))
 667 +               return 1;
 668 +       if (fd_pair(tls_write))
 669 +               return 1;
 670 +
 671 +       set_blocking(tls_read[0]);
 672 +       set_blocking(tls_read[1]);
 673 +       set_blocking(tls_write[0]);
 674 +       set_blocking(tls_write[1]);
 675 +       set_blocking(f_in);
 676 +       set_blocking(f_out);
 677 +
 678 +       ssl_pid = do_fork();
 679 +       if (ssl_pid < 0)
 680 +               return -1;
 681 +       if (ssl_pid != 0) {
 682 +               close(tls_write[0]);
 683 +               close(tls_read[1]);
 684 +               return 0;
 685 +       }
 686 +
 687 +       SIGACTION(SIGUSR1, tls_sigusr1);
 688 +       ssl = SSL_new(ssl_ctx);
 689 +       if (!ssl)
 690 +               goto closed;
 691 +       if (am_daemon || am_server)
 692 +               SSL_set_accept_state(ssl);
 693 +       else
 694 +               SSL_set_connect_state(ssl);
 695 +       SSL_set_rfd(ssl, f_in);
 696 +       SSL_set_wfd(ssl, f_out);
 697 +
 698 +       tls_fd = SSL_get_fd(ssl);
 699 +       n = tls_write[0];
 700 +       n = MAX(tls_read[1], n);
 701 +       n = MAX(tls_fd, n) + 1;
 702 +
 703 +       ssl_running = 1;
 704 +       while (ssl_running) {
 705 +               FD_ZERO(&rd);
 706 +               FD_ZERO(&wd);
 707 +               FD_SET(tls_write[0], &rd);
 708 +               FD_SET(tls_read[1], &wd);
 709 +               FD_SET(tls_fd, &rd);
 710 +               FD_SET(tls_fd, &wd);
 711 +
 712 +               r = select(n, &rd, &wd, NULL, NULL);
 713 +
 714 +               if (r == -1 && errno == EINTR)
 715 +                       continue;
 716 +               if (FD_ISSET(tls_write[0], &rd)) {
 717 +                       r = read(tls_write[0], buf1+avail1, BUF_SIZE-avail1);
 718 +                       if (r >= 0)
 719 +                               avail1 += r;
 720 +                       else {
 721 +                               rprintf(FERROR, "pipe read error: %s\n",
 722 +                                       strerror(errno));
 723 +                               break;
 724 +                       }
 725 +               }
 726 +               if (FD_ISSET(tls_fd, &rd)) {
 727 +                       r = SSL_read(ssl, buf2+avail2, BUF_SIZE-avail2);
 728 +                       if (r > 0)
 729 +                               avail2 += r;
 730 +                       else {
 731 +                               switch (SSL_get_error(ssl, r)) {
 732 +                               case SSL_ERROR_ZERO_RETURN:
 733 +                                       goto closed;
 734 +                               case SSL_ERROR_WANT_READ:
 735 +                               case SSL_ERROR_WANT_WRITE:
 736 +                                       break;
 737 +                               case SSL_ERROR_SYSCALL:
 738 +                                       if (r == 0)
 739 +                                               rprintf(FERROR, "SSL spurious EOF\n");
 740 +                                       else
 741 +                                               rprintf(FERROR, "SSL I/O error: %s\n",
 742 +                                                       strerror(errno));
 743 +                                       goto closed;
 744 +                               case SSL_ERROR_SSL:
 745 +                                       rprintf(FERROR, "SSL: %s\n",
 746 +                                               ERR_error_string(ERR_get_error(), NULL));
 747 +                                       goto closed;
 748 +                               default:
 749 +                                       rprintf(FERROR, "unexpected ssl error %d\n", r);
 750 +                                       goto closed;
 751 +                               }
 752 +                       }
 753 +               }
 754 +               if (FD_ISSET(tls_read[1], &wd) && write2 < avail2) {
 755 +                       r = write(tls_read[1], buf2+write2, avail2-write2);
 756 +                       if (r >= 0)
 757 +                               write2 += r;
 758 +                       else {
 759 +                               rprintf(FERROR, "pipe write error: %s\n",
 760 +                                       strerror(errno));
 761 +                               break;
 762 +                       }
 763 +               }
 764 +               if (FD_ISSET(tls_fd, &wd) && write1 < avail1) {
 765 +                       r = SSL_write(ssl, buf1+write1, avail1-write1);
 766 +                       if (r > 0)
 767 +                               write1 += r;
 768 +                       else {
 769 +                               switch (SSL_get_error(ssl, r)) {
 770 +                               case SSL_ERROR_ZERO_RETURN:
 771 +                                       goto closed;
 772 +                               case SSL_ERROR_WANT_READ:
 773 +                               case SSL_ERROR_WANT_WRITE:
 774 +                                       break;
 775 +                               case SSL_ERROR_SYSCALL:
 776 +                                       if (r == 0)
 777 +                                               rprintf(FERROR, "SSL: spurious EOF\n");
 778 +                                       else
 779 +                                               rprintf(FERROR, "SSL: I/O error: %s\n",
 780 +                                                       strerror(errno));
 781 +                                       goto closed;
 782 +                               case SSL_ERROR_SSL:
 783 +                                       rprintf(FERROR, "SSL: %s\n",
 784 +                                               ERR_error_string(ERR_get_error(), NULL));
 785 +                                       goto closed;
 786 +                               default:
 787 +                                       rprintf(FERROR, "unexpected ssl error %d\n", r);
 788 +                                       goto closed;
 789 +                               }
 790 +                       }
 791 +               }
 792 +               if (avail1 == write1)
 793 +                       avail1 = write1 = 0;
 794 +               if (avail2 == write2)
 795 +                       avail2 = write2 = 0;
 796 +       }
 797 +
 798 +       /* XXX I'm pretty sure that there is a lot that I am not considering
 799 +          here. Bugs? Yes, probably. */
 800 +
 801 +       /* We're finished. */
 802 +    closed:
 803 +       close(tls_read[1]);
 804 +       close(tls_write[0]);
 805 +       exit(0);
 806 +}
 807 +
 808 +/**
 809 + * Ends the TLS connection.
 810 + */
 811 +void end_tls(void)
 812 +{
 813 +       if (ssl_pid > 0)
 814 +               kill(ssl_pid, SIGUSR1);
 815 +}