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 diff --git a/Makefile.in b/Makefile.in
  39 --- a/Makefile.in
  40 +++ b/Makefile.in
  41 @@ -40,7 +40,7 @@ OBJS3=progress.o pipe.o
  42  DAEMON_OBJ = params.o loadparm.o clientserver.o access.o connection.o authenticate.o
  43  popt_OBJS=popt/findme.o  popt/popt.o  popt/poptconfig.o \
  44         popt/popthelp.o popt/poptparse.o
  45 -OBJS=$(OBJS1) $(OBJS2) $(OBJS3) $(DAEMON_OBJ) $(LIBOBJ) $(ZLIBOBJ) @BUILD_POPT@
  46 +OBJS=$(OBJS1) $(OBJS2) $(OBJS3) $(DAEMON_OBJ) $(LIBOBJ) $(ZLIBOBJ) @BUILD_POPT@ @SSL_OBJS@
  47
  48  TLS_OBJ = tls.o syscall.o lib/compat.o lib/snprintf.o lib/permstring.o lib/sysxattrs.o @BUILD_POPT@
  49
  50 diff --git a/cleanup.c b/cleanup.c
  51 --- a/cleanup.c
  52 +++ b/cleanup.c
  53 @@ -25,6 +25,9 @@
  54  extern int am_server;
  55  extern int am_daemon;
  56  extern int io_error;
  57 +#ifdef HAVE_OPENSSL
  58 +extern int use_ssl;
  59 +#endif
  60  extern int keep_partial;
  61  extern int got_xfer_error;
  62  extern int progress_is_active;
  63 @@ -125,6 +128,14 @@ NORETURN void _exit_cleanup(int code, const char *file, int line)
  64                                 code, file, line);
  65                 }
  66
  67 +#ifdef HAVE_OPENSSL
  68 +               /* FALLTHROUGH */
  69 +#include "case_N.h"
  70 +
  71 +               if (use_ssl)
  72 +                       end_tls();
  73 +#endif
  74 +
  75                 /* FALLTHROUGH */
  76  #include "case_N.h"
  77
  78 diff --git a/clientserver.c b/clientserver.c
  79 --- a/clientserver.c
  80 +++ b/clientserver.c
  81 @@ -31,6 +31,9 @@ extern int am_sender;
  82  extern int am_server;
  83  extern int am_daemon;
  84  extern int am_root;
  85 +#ifdef HAVE_OPENSSL
  86 +extern int use_ssl;
  87 +#endif
  88  extern int rsync_port;
  89  extern int protect_args;
  90  extern int ignore_errors;
  91 @@ -126,8 +129,18 @@ int start_socket_client(char *host, int remote_argc, char *remote_argv[],
  92  #endif
  93
  94         ret = start_inband_exchange(fd, fd, user, remote_argc, remote_argv);
  95 +       if (ret)
  96 +               return ret;
  97 +
  98 +#ifdef HAVE_OPENSSL
  99 +       if (use_ssl) {
 100 +               int f_in = get_tls_rfd();
 101 +               int f_out = get_tls_wfd();
 102 +               return client_run(f_in, f_out, -1, argc, argv);
 103 +       }
 104 +#endif
 105
 106 -       return ret ? ret : client_run(fd, fd, -1, argc, argv);
 107 +       return client_run(fd, fd, -1, argc, argv);
 108  }
 109
 110  static int exchange_protocols(int f_in, int f_out, char *buf, size_t bufsiz, int am_client)
 111 @@ -270,6 +283,32 @@ int start_inband_exchange(int f_in, int f_out, const char *user, int argc, char
 112         if (verbose > 1)
 113                 print_child_argv("sending daemon args:", sargs);
 114
 115 +#ifdef HAVE_OPENSSL
 116 +       if (use_ssl) {
 117 +               io_printf(f_out, "#starttls\n");
 118 +               while (1) {
 119 +                       if (!read_line_old(f_in, line, sizeof line)) {
 120 +                               rprintf(FERROR, "rsync: did not receive reply to #starttls\n");
 121 +                               return -1;
 122 +                       }
 123 +                       if (strncmp(line, "@ERROR", 6) == 0) {
 124 +                               rprintf(FERROR, "%s\n", line);
 125 +                               return -1;
 126 +                       }
 127 +                       if (strcmp(line, "@RSYNCD: starttls") == 0)
 128 +                               break;
 129 +                       rprintf(FINFO, "%s\n", line);
 130 +               }
 131 +               if (start_tls(f_in, f_out)) {
 132 +                       rprintf(FERROR, "rsync: error during SSL handshake: %s\n",
 133 +                               get_ssl_error());
 134 +                       return -1;
 135 +               }
 136 +               f_in = get_tls_rfd();
 137 +               f_out = get_tls_wfd();
 138 +       }
 139 +#endif
 140 +
 141         io_printf(f_out, "%.*s\n", modlen, modname);
 142
 143         /* Old servers may just drop the connection here,
 144 @@ -295,6 +334,10 @@ int start_inband_exchange(int f_in, int f_out, const char *user, int argc, char
 145                          * server to terminate the listing of modules.
 146                          * We don't want to go on and transfer
 147                          * anything; just exit. */
 148 +#ifdef HAVE_OPENSSL
 149 +                       if (use_ssl)
 150 +                               end_tls();
 151 +#endif
 152                         exit(0);
 153                 }
 154
 155 @@ -302,6 +345,10 @@ int start_inband_exchange(int f_in, int f_out, const char *user, int argc, char
 156                         rprintf(FERROR, "%s\n", line);
 157                         /* This is always fatal; the server will now
 158                          * close the socket. */
 159 +#ifdef HAVE_OPENSSL
 160 +                       if (use_ssl)
 161 +                               end_tls();
 162 +#endif
 163                         return -1;
 164                 }
 165
 166 @@ -935,6 +982,9 @@ int start_daemon(int f_in, int f_out)
 167         if (exchange_protocols(f_in, f_out, line, sizeof line, 0) < 0)
 168                 return -1;
 169
 170 +#ifdef HAVE_OPENSSL
 171 +retry:
 172 +#endif
 173         line[0] = 0;
 174         if (!read_line_old(f_in, line, sizeof line))
 175                 return -1;
 176 @@ -946,6 +996,20 @@ int start_daemon(int f_in, int f_out)
 177                 return -1;
 178         }
 179
 180 +#ifdef HAVE_OPENSSL
 181 +       if (use_ssl && strcmp(line, "#starttls") == 0) {
 182 +               io_printf(f_out, "@RSYNCD: starttls\n");
 183 +               if (start_tls(f_in, f_out)) {
 184 +                       rprintf(FLOG, "SSL connection failed: %s\n",
 185 +                               get_ssl_error());
 186 +                       return -1;
 187 +               }
 188 +               f_in = get_tls_rfd();
 189 +               f_out = get_tls_wfd();
 190 +               goto retry;
 191 +       }
 192 +#endif
 193 +
 194         if (*line == '#') {
 195                 /* it's some sort of command that I don't understand */
 196                 io_printf(f_out, "@ERROR: Unknown command '%s'\n", line);
 197 diff --git a/configure.in b/configure.in
 198 --- a/configure.in
 199 +++ b/configure.in
 200 @@ -295,6 +295,21 @@ if test x"$enable_locale" != x"no"; then
 201         AC_DEFINE(CONFIG_LOCALE)
 202  fi
 203
 204 +AC_ARG_ENABLE(openssl,
 205 +              AC_HELP_STRING([--enable-openssl], [compile SSL support with OpenSSL.]))
 206 +
 207 +if test "x$enable_openssl" != xno
 208 +then
 209 +       have_ssl=yes
 210 +       AC_CHECK_LIB(ssl, SSL_library_init, , [have_ssl=no])
 211 +       if test "x$have_ssl" = xyes
 212 +       then
 213 +               AC_DEFINE(HAVE_OPENSSL, 1, [true if you want to use SSL.])
 214 +               SSL_OBJS=ssl.o
 215 +               AC_SUBST(SSL_OBJS)
 216 +       fi
 217 +fi
 218 +
 219  AC_MSG_CHECKING([whether to call shutdown on all sockets])
 220  case $host_os in
 221         *cygwin* ) AC_MSG_RESULT(yes)
 222 diff --git a/options.c b/options.c
 223 --- a/options.c
 224 +++ b/options.c
 225 @@ -185,6 +185,14 @@ int logfile_format_has_o_or_i = 0;
 226  int always_checksum = 0;
 227  int list_only = 0;
 228
 229 +#ifdef HAVE_OPENSSL
 230 +int use_ssl = 0;
 231 +char *ssl_cert_path = NULL;
 232 +char *ssl_key_path = NULL;
 233 +char *ssl_key_passwd = NULL;
 234 +char *ssl_ca_path = NULL;
 235 +#endif
 236 +
 237  #define MAX_BATCH_NAME_LEN 256 /* Must be less than MAXPATHLEN-13 */
 238  char *batch_name = NULL;
 239
 240 @@ -225,6 +233,7 @@ static void print_rsync_version(enum logcode f)
 241         char const *links = "no ";
 242         char const *iconv = "no ";
 243         char const *ipv6 = "no ";
 244 +       char const *ssl = "no ";
 245         STRUCT_STAT *dumstat;
 246
 247  #if SUBPROTOCOL_VERSION != 0
 248 @@ -257,6 +266,9 @@ static void print_rsync_version(enum logcode f)
 249  #if defined HAVE_LUTIMES && defined HAVE_UTIMES
 250         symtimes = "";
 251  #endif
 252 +#ifdef HAVE_OPENSSL
 253 +       ssl = "";
 254 +#endif
 255
 256         rprintf(f, "%s  version %s  protocol version %d%s\n",
 257                 RSYNC_NAME, RSYNC_VERSION, PROTOCOL_VERSION, subprotocol);
 258 @@ -270,8 +282,8 @@ static void print_rsync_version(enum logcode f)
 259                 (int)(sizeof (int64) * 8));
 260         rprintf(f, "    %ssocketpairs, %shardlinks, %ssymlinks, %sIPv6, batchfiles, %sinplace,\n",
 261                 got_socketpair, hardlinks, links, ipv6, have_inplace);
 262 -       rprintf(f, "    %sappend, %sACLs, %sxattrs, %siconv, %ssymtimes\n",
 263 -               have_inplace, acls, xattrs, iconv, symtimes);
 264 +       rprintf(f, "    %sappend, %sACLs, %sxattrs, %siconv, %ssymtimes, %sSSL\n",
 265 +               have_inplace, acls, xattrs, iconv, symtimes, ssl);
 266
 267  #ifdef MAINTAINER_MODE
 268         rprintf(f, "Panic Action: \"%s\"\n", get_panic_action());
 269 @@ -433,6 +445,13 @@ void usage(enum logcode F)
 270  #endif
 271    rprintf(F," -4, --ipv4                  prefer IPv4\n");
 272    rprintf(F," -6, --ipv6                  prefer IPv6\n");
 273 +#ifdef HAVE_OPENSSL
 274 +  rprintf(F,"     --ssl                   allow socket connections to use SSL\n");
 275 +  rprintf(F,"     --ssl-cert=FILE         path to daemon's SSL certificate\n");
 276 +  rprintf(F,"     --ssl-key=FILE          path to daemon's SSL private key\n");
 277 +  rprintf(F,"     --ssl-key-passwd=PASS   password for PEM-encoded private key\n");
 278 +  rprintf(F,"     --ssl-ca-certs=FILE     path to trusted CA certificates\n");
 279 +#endif
 280    rprintf(F,"     --version               print version number\n");
 281    rprintf(F,"(-h) --help                  show this help (-h works with no other options)\n");
 282
 283 @@ -446,7 +465,7 @@ enum {OPT_VERSION = 1000, OPT_DAEMON, OPT_SENDER, OPT_EXCLUDE, OPT_EXCLUDE_FROM,
 284        OPT_FILTER, OPT_COMPARE_DEST, OPT_COPY_DEST, OPT_LINK_DEST, OPT_HELP,
 285        OPT_INCLUDE, OPT_INCLUDE_FROM, OPT_MODIFY_WINDOW, OPT_MIN_SIZE, OPT_CHMOD,
 286        OPT_READ_BATCH, OPT_WRITE_BATCH, OPT_ONLY_WRITE_BATCH, OPT_MAX_SIZE,
 287 -      OPT_NO_D, OPT_APPEND, OPT_NO_ICONV,
 288 +      OPT_NO_D, OPT_APPEND, OPT_NO_ICONV, OPT_USE_SSL,
 289        OPT_SERVER, OPT_REFUSED_BASE = 9000};
 290
 291  static struct poptOption long_options[] = {
 292 @@ -649,6 +668,13 @@ static struct poptOption long_options[] = {
 293    {"checksum-seed",    0,  POPT_ARG_INT,    &checksum_seed, 0, 0, 0 },
 294    {"server",           0,  POPT_ARG_NONE,   0, OPT_SERVER, 0, 0 },
 295    {"sender",           0,  POPT_ARG_NONE,   0, OPT_SENDER, 0, 0 },
 296 +#ifdef HAVE_OPENSSL
 297 +  {"ssl",              0,  POPT_ARG_NONE,   0, OPT_USE_SSL, 0, 0},
 298 +  {"ssl-cert",         0,  POPT_ARG_STRING, &ssl_cert_path, OPT_USE_SSL, 0, 0},
 299 +  {"ssl-key",          0,  POPT_ARG_STRING, &ssl_key_path, OPT_USE_SSL, 0, 0},
 300 +  {"ssl-key-passwd",   0,  POPT_ARG_STRING, &ssl_key_passwd, OPT_USE_SSL, 0, 0},
 301 +  {"ssl-ca-certs",     0,  POPT_ARG_STRING, &ssl_ca_path, OPT_USE_SSL, 0, 0},
 302 +#endif
 303    /* All the following options switch us into daemon-mode option-parsing. */
 304    {"config",           0,  POPT_ARG_STRING, 0, OPT_DAEMON, 0, 0 },
 305    {"daemon",           0,  POPT_ARG_NONE,   0, OPT_DAEMON, 0, 0 },
 306 @@ -674,6 +700,13 @@ static void daemon_usage(enum logcode F)
 307    rprintf(F," -v, --verbose               increase verbosity\n");
 308    rprintf(F," -4, --ipv4                  prefer IPv4\n");
 309    rprintf(F," -6, --ipv6                  prefer IPv6\n");
 310 +#ifdef HAVE_OPENSSL
 311 +  rprintf(F,"     --ssl                   allow socket connections to use SSL\n");
 312 +  rprintf(F,"     --ssl-cert=FILE         path to daemon's SSL certificate\n");
 313 +  rprintf(F,"     --ssl-key=FILE          path to daemon's SSL private key\n");
 314 +  rprintf(F,"     --ssl-key-passwd=PASS   password for PEM-encoded private key\n");
 315 +  rprintf(F,"     --ssl-ca-certs=FILE     path to trusted CA certificates\n");
 316 +#endif
 317    rprintf(F,"     --help                  show this help screen\n");
 318
 319    rprintf(F,"\n");
 320 @@ -698,6 +731,13 @@ static struct poptOption long_daemon_options[] = {
 321    {"protocol",         0,  POPT_ARG_INT,    &protocol_version, 0, 0, 0 },
 322    {"server",           0,  POPT_ARG_NONE,   &am_server, 0, 0, 0 },
 323    {"temp-dir",        'T', POPT_ARG_STRING, &tmpdir, 0, 0, 0 },
 324 +#ifdef HAVE_OPENSSL
 325 +  {"ssl",              0,  POPT_ARG_NONE,   0, OPT_USE_SSL, 0, 0},
 326 +  {"ssl-cert",         0,  POPT_ARG_STRING, &ssl_cert_path, OPT_USE_SSL, 0, 0},
 327 +  {"ssl-key",          0,  POPT_ARG_STRING, &ssl_key_path, OPT_USE_SSL, 0, 0},
 328 +  {"ssl-key-passwd",   0,  POPT_ARG_STRING, &ssl_key_passwd, OPT_USE_SSL, 0, 0},
 329 +  {"ssl-ca-certs",     0,  POPT_ARG_STRING, &ssl_ca_path, OPT_USE_SSL, 0, 0},
 330 +#endif
 331    {"verbose",         'v', POPT_ARG_NONE,   0, 'v', 0, 0 },
 332    {"no-verbose",       0,  POPT_ARG_VAL,    &verbose, 0, 0, 0 },
 333    {"no-v",             0,  POPT_ARG_VAL,    &verbose, 0, 0, 0 },
 334 @@ -979,6 +1019,12 @@ int parse_arguments(int *argc_p, const char ***argv_p)
 335                                         verbose++;
 336                                         break;
 337
 338 +#ifdef HAVE_OPENSSL
 339 +                               case OPT_USE_SSL:
 340 +                                       use_ssl = 1;
 341 +                                       break;
 342 +#endif
 343 +
 344                                 default:
 345                                         rprintf(FERROR,
 346                                             "rsync: %s: %s (in daemon mode)\n",
 347 @@ -1002,6 +1048,17 @@ int parse_arguments(int *argc_p, const char ***argv_p)
 348                                 exit_cleanup(RERR_SYNTAX);
 349                         }
 350
 351 +#ifdef HAVE_OPENSSL
 352 +                       if (use_ssl) {
 353 +                               if (init_tls()) {
 354 +                                       snprintf(err_buf, sizeof(err_buf),
 355 +                                                "Openssl error: %s\n",
 356 +                                                get_ssl_error());
 357 +                                       return 0;
 358 +                               }
 359 +                       }
 360 +#endif
 361 +
 362                         *argv_p = argv = poptGetArgs(pc);
 363                         *argc_p = argc = count_args(argv);
 364                         am_starting_up = 0;
 365 @@ -1260,6 +1317,12 @@ int parse_arguments(int *argc_p, const char ***argv_p)
 366                         return 0;
 367  #endif
 368
 369 +#ifdef HAVE_OPENSSL
 370 +               case OPT_USE_SSL:
 371 +                       use_ssl = 1;
 372 +                       break;
 373 +#endif
 374 +
 375                 default:
 376                         /* A large opt value means that set_refuse_options()
 377                          * turned this option off. */
 378 @@ -1593,6 +1656,17 @@ int parse_arguments(int *argc_p, const char ***argv_p)
 379         if (delay_updates && !partial_dir)
 380                 partial_dir = tmp_partialdir;
 381
 382 +#ifdef HAVE_OPENSSL
 383 +       if (use_ssl) {
 384 +               if (init_tls()) {
 385 +                       snprintf(err_buf, sizeof(err_buf),
 386 +                                "Openssl error: %s\n",
 387 +                                get_ssl_error());
 388 +                       return 0;
 389 +               }
 390 +       }
 391 +#endif
 392 +
 393         if (inplace) {
 394  #ifdef HAVE_FTRUNCATE
 395                 if (partial_dir) {
 396 @@ -2067,10 +2141,27 @@ char *check_for_hostspec(char *s, char **host_ptr, int *port_ptr)
 397         char *p;
 398         int not_host;
 399         int hostlen;
 400 -
 401 -       if (port_ptr && strncasecmp(URL_PREFIX, s, strlen(URL_PREFIX)) == 0) {
 402 +       int url_prefix_len = sizeof URL_PREFIX - 1;
 403 +
 404 +       if (!port_ptr)
 405 +               url_prefix_len = 0;
 406 +       else if (strncasecmp(URL_PREFIX, s, url_prefix_len) != 0) {
 407 +#ifdef HAVE_OPENSSL
 408 +               url_prefix_len = sizeof SSL_URL_PREFIX - 1;
 409 +               if (strncasecmp(SSL_URL_PREFIX, s, url_prefix_len) != 0)
 410 +                       url_prefix_len = 0;
 411 +               else {
 412 +                       if (!use_ssl)
 413 +                               init_tls();
 414 +                       use_ssl = 1;
 415 +               }
 416 +#else
 417 +               url_prefix_len = 0;
 418 +#endif
 419 +       }
 420 +       if (url_prefix_len) {
 421                 char *path;
 422 -               s += strlen(URL_PREFIX);
 423 +               s += url_prefix_len;
 424                 if ((p = strchr(s, '/')) != NULL) {
 425                         hostlen = p - s;
 426                         path = p + 1;
 427 diff --git a/rsync.h b/rsync.h
 428 --- a/rsync.h
 429 +++ b/rsync.h
 430 @@ -31,6 +31,7 @@
 431
 432  #define DEFAULT_LOCK_FILE "/var/run/rsyncd.lock"
 433  #define URL_PREFIX "rsync://"
 434 +#define SSL_URL_PREFIX "rsyncs://"
 435
 436  #define SYMLINK_PREFIX "/rsyncd-munged/"
 437  #define SYMLINK_PREFIX_LEN ((int)sizeof SYMLINK_PREFIX - 1)
 438 @@ -543,6 +544,11 @@ typedef unsigned int size_t;
 439  # define SIZEOF_INT64 SIZEOF_OFF_T
 440  #endif
 441
 442 +#ifdef HAVE_OPENSSL
 443 +#include <openssl/ssl.h>
 444 +#include <openssl/err.h>
 445 +#endif
 446 +
 447  struct hashtable {
 448         void *nodes;
 449         int32 size, entries;
 450 diff --git a/ssl.c b/ssl.c
 451 new file mode 100644
 452 --- /dev/null
 453 +++ b/ssl.c
 454 @@ -0,0 +1,370 @@
 455 +/* -*- c-file-style: "linux" -*-
 456 + * ssl.c: operations for negotiating SSL rsync connections.
 457 + *
 458 + * Copyright (C) 2003  Casey Marshall <rsdio@metastatic.org>
 459 + *
 460 + * This program is free software; you can redistribute it and/or modify
 461 + * it under the terms of the GNU General Public License as published by
 462 + * the Free Software Foundation; either version 2 of the License, or
 463 + * (at your option) any later version.
 464 + *
 465 + * This program is distributed in the hope that it will be useful,
 466 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
 467 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 468 + * GNU General Public License for more details.
 469 + *
 470 + * You should have received a copy of the GNU General Public License
 471 + * along with this program; if not, write to the Free Software
 472 + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 473 + */
 474 +
 475 +#include "rsync.h"
 476 +
 477 +#ifdef HAVE_SYS_SELECT_H
 478 +#include <sys/select.h>
 479 +#else
 480 +#include <sys/time.h>
 481 +#include <sys/types.h>
 482 +#include <unistd.h>
 483 +#endif
 484 +#include <string.h>
 485 +
 486 +#define BUF_SIZE 1024
 487 +
 488 +extern int verbose;
 489 +extern int am_daemon;
 490 +extern int am_server;
 491 +
 492 +extern char *ssl_cert_path;
 493 +extern char *ssl_key_path;
 494 +extern char *ssl_key_passwd;
 495 +extern char *ssl_ca_path;
 496 +
 497 +static SSL_CTX *ssl_ctx;
 498 +static SSL *ssl;
 499 +static int tls_read[2] = { -1, -1 };
 500 +static int tls_write[2] = { -1, -1 };
 501 +static int ssl_running;
 502 +static int ssl_pid = -1;
 503 +
 504 +#ifdef HAVE_SIGACTION
 505 +static struct sigaction sigact;
 506 +#endif
 507 +
 508 +/**
 509 + * A non-interactive callback to be passed to SSL_CTX_set_default_password_cb,
 510 + * which merely copies the value of ssl_key_passwd into buf. This is
 511 + * used for when the private key password is supplied via an option.
 512 + */
 513 +static int default_password_cb(char *buf, int n, UNUSED(int f), UNUSED(void *u))
 514 +{
 515 +       if (ssl_key_passwd == NULL || n < (int)strlen(ssl_key_passwd))
 516 +               return 0;
 517 +       strncpy(buf, ssl_key_passwd, n-1);
 518 +       return strlen(ssl_key_passwd);
 519 +}
 520 +
 521 +/**
 522 + * If verbose, this method traces the status of the SSL handshake.
 523 + */
 524 +static void info_callback(const SSL *ssl, int cb, int val)
 525 +{
 526 +       char buf[128];
 527 +       char *cbs;
 528 +
 529 +       switch (cb) {
 530 +       case SSL_CB_LOOP:
 531 +               cbs = "SSL_CB_LOOP";
 532 +               break;
 533 +       case SSL_CB_EXIT:
 534 +               cbs = "SSL_CB_EXIT";
 535 +               break;
 536 +       case SSL_CB_READ:
 537 +               cbs = "SSL_CB_READ";
 538 +               break;
 539 +       case SSL_CB_WRITE:
 540 +               cbs = "SSL_CB_WRITE";
 541 +               break;
 542 +       case SSL_CB_ALERT:
 543 +               cbs = "SSL_CB_ALERT";
 544 +               break;
 545 +       case SSL_CB_READ_ALERT:
 546 +               cbs = "SSL_CB_READ_ALERT";
 547 +               break;
 548 +       case SSL_CB_WRITE_ALERT:
 549 +               cbs = "SSL_CB_WRITE_ALERT";
 550 +               break;
 551 +       case SSL_CB_ACCEPT_LOOP:
 552 +               cbs = "SSL_CB_ACCEPT_LOOP";
 553 +               break;
 554 +       case SSL_CB_ACCEPT_EXIT:
 555 +               cbs = "SSL_CB_ACCEPT_EXIT";
 556 +               break;
 557 +       case SSL_CB_CONNECT_LOOP:
 558 +               cbs = "SSL_CB_CONNECT_LOOP";
 559 +               break;
 560 +       case SSL_CB_CONNECT_EXIT:
 561 +               cbs = "SSL_CB_CONNECT_EXIT";
 562 +               break;
 563 +       case SSL_CB_HANDSHAKE_START:
 564 +               cbs = "SSL_CB_HANDSHAKE_START";
 565 +               break;
 566 +       case SSL_CB_HANDSHAKE_DONE:
 567 +               cbs = "SSL_CB_HANDSHAKE_DONE";
 568 +               break;
 569 +       default:
 570 +               snprintf(buf, sizeof buf, "??? (%d)", cb);
 571 +               cbs = buf;
 572 +               break;
 573 +       }
 574 +       if (verbose > 2) {
 575 +               rprintf(FLOG, "SSL: info_callback(%p,%s,%d)\n", ssl, cbs, val);
 576 +               if (cb == SSL_CB_HANDSHAKE_DONE) {
 577 +                       SSL_CIPHER_description(SSL_get_current_cipher((SSL*)ssl),
 578 +                                              buf, sizeof buf);
 579 +                       rprintf(FLOG, "SSL: cipher: %s", buf);
 580 +               }
 581 +       }
 582 +}
 583 +
 584 +/**
 585 + * Initializes the SSL context for TLSv1 connections; returns zero on
 586 + * success.
 587 + */
 588 +int init_tls(void)
 589 +{
 590 +       if (ssl_ctx)
 591 +               return 0;
 592 +       SSL_library_init();
 593 +       SSL_load_error_strings();
 594 +       ssl_ctx = SSL_CTX_new(TLSv1_method());
 595 +       if (!ssl_ctx)
 596 +               return 1;
 597 +       SSL_CTX_set_info_callback(ssl_ctx, info_callback);
 598 +
 599 +       /* Sets the certificate sent to the other party. */
 600 +       if (ssl_cert_path != NULL
 601 +           && SSL_CTX_use_certificate_file(ssl_ctx, ssl_cert_path,
 602 +                                           SSL_FILETYPE_PEM) != 1)
 603 +               return 1;
 604 +       /* Set up the simple non-interactive callback if the password
 605 +        * was supplied on the command line. */
 606 +       if (ssl_key_passwd != NULL)
 607 +               SSL_CTX_set_default_passwd_cb(ssl_ctx, default_password_cb);
 608 +       /* Sets the private key that matches the public certificate. */
 609 +       if (ssl_key_path != NULL) {
 610 +               if (SSL_CTX_use_PrivateKey_file(ssl_ctx, ssl_key_path,
 611 +                                               SSL_FILETYPE_PEM) != 1)
 612 +                       return 1;
 613 +               if (SSL_CTX_check_private_key(ssl_ctx) != 1)
 614 +                       return 1;
 615 +       }
 616 +       if (ssl_ca_path != NULL
 617 +           && !SSL_CTX_load_verify_locations(ssl_ctx, ssl_ca_path, NULL))
 618 +               return 1;
 619 +
 620 +       return 0;
 621 +}
 622 +
 623 +/**
 624 + * Returns the error string for the current SSL error, if any.
 625 + */
 626 +char *get_ssl_error(void)
 627 +{
 628 +       return ERR_error_string(ERR_get_error(), NULL);
 629 +}
 630 +
 631 +/**
 632 + * Returns the input file descriptor for the SSL connection.
 633 + */
 634 +int get_tls_rfd(void)
 635 +{
 636 +       return tls_read[0];
 637 +}
 638 +
 639 +/**
 640 + * Returns the output file descriptor for the SSL connection.
 641 + */
 642 +int get_tls_wfd(void)
 643 +{
 644 +       return tls_write[1];
 645 +}
 646 +
 647 +/**
 648 + * Signal handler that ends the SSL connection.
 649 + */
 650 +static RETSIGTYPE tls_sigusr1(int UNUSED(val))
 651 +{
 652 +       if (ssl) {
 653 +               SSL_shutdown(ssl);
 654 +               SSL_free(ssl);
 655 +               ssl = NULL;
 656 +       }
 657 +       ssl_running = 0;
 658 +}
 659 +
 660 +/**
 661 + * Negotiates the TLS connection, creates a socket pair for communicating
 662 + * with the rsync process, then forks into a new process that will handle
 663 + * the communication.
 664 + *
 665 + * 0 is returned on success.
 666 + */
 667 +int start_tls(int f_in, int f_out)
 668 +{
 669 +       int tls_fd;
 670 +       int n = 0, r;
 671 +       unsigned char buf1[BUF_SIZE], buf2[BUF_SIZE];
 672 +       int avail1 = 0, avail2 = 0, write1 = 0, write2 = 0;
 673 +       fd_set rd, wd;
 674 +
 675 +       if (fd_pair(tls_read))
 676 +               return 1;
 677 +       if (fd_pair(tls_write))
 678 +               return 1;
 679 +
 680 +       set_blocking(tls_read[0]);
 681 +       set_blocking(tls_read[1]);
 682 +       set_blocking(tls_write[0]);
 683 +       set_blocking(tls_write[1]);
 684 +       set_blocking(f_in);
 685 +       set_blocking(f_out);
 686 +
 687 +       ssl_pid = do_fork();
 688 +       if (ssl_pid < 0)
 689 +               return -1;
 690 +       if (ssl_pid != 0) {
 691 +               close(tls_write[0]);
 692 +               close(tls_read[1]);
 693 +               return 0;
 694 +       }
 695 +
 696 +       SIGACTION(SIGUSR1, tls_sigusr1);
 697 +       ssl = SSL_new(ssl_ctx);
 698 +       if (!ssl)
 699 +               goto closed;
 700 +       if (am_daemon || am_server)
 701 +               SSL_set_accept_state(ssl);
 702 +       else
 703 +               SSL_set_connect_state(ssl);
 704 +       SSL_set_rfd(ssl, f_in);
 705 +       SSL_set_wfd(ssl, f_out);
 706 +
 707 +       tls_fd = SSL_get_fd(ssl);
 708 +       n = tls_write[0];
 709 +       n = MAX(tls_read[1], n);
 710 +       n = MAX(tls_fd, n) + 1;
 711 +
 712 +       ssl_running = 1;
 713 +       while (ssl_running) {
 714 +               FD_ZERO(&rd);
 715 +               FD_ZERO(&wd);
 716 +               FD_SET(tls_write[0], &rd);
 717 +               FD_SET(tls_read[1], &wd);
 718 +               FD_SET(tls_fd, &rd);
 719 +               FD_SET(tls_fd, &wd);
 720 +
 721 +               r = select(n, &rd, &wd, NULL, NULL);
 722 +
 723 +               if (r == -1 && errno == EINTR)
 724 +                       continue;
 725 +               if (FD_ISSET(tls_write[0], &rd)) {
 726 +                       r = read(tls_write[0], buf1+avail1, BUF_SIZE-avail1);
 727 +                       if (r >= 0)
 728 +                               avail1 += r;
 729 +                       else {
 730 +                               rprintf(FERROR, "pipe read error: %s\n",
 731 +                                       strerror(errno));
 732 +                               break;
 733 +                       }
 734 +               }
 735 +               if (FD_ISSET(tls_fd, &rd)) {
 736 +                       r = SSL_read(ssl, buf2+avail2, BUF_SIZE-avail2);
 737 +                       if (r > 0)
 738 +                               avail2 += r;
 739 +                       else {
 740 +                               switch (SSL_get_error(ssl, r)) {
 741 +                               case SSL_ERROR_ZERO_RETURN:
 742 +                                       goto closed;
 743 +                               case SSL_ERROR_WANT_READ:
 744 +                               case SSL_ERROR_WANT_WRITE:
 745 +                                       break;
 746 +                               case SSL_ERROR_SYSCALL:
 747 +                                       if (r == 0)
 748 +                                               rprintf(FERROR, "SSL spurious EOF\n");
 749 +                                       else
 750 +                                               rprintf(FERROR, "SSL I/O error: %s\n",
 751 +                                                       strerror(errno));
 752 +                                       goto closed;
 753 +                               case SSL_ERROR_SSL:
 754 +                                       rprintf(FERROR, "SSL: %s\n",
 755 +                                               ERR_error_string(ERR_get_error(), NULL));
 756 +                                       goto closed;
 757 +                               default:
 758 +                                       rprintf(FERROR, "unexpected ssl error %d\n", r);
 759 +                                       goto closed;
 760 +                               }
 761 +                       }
 762 +               }
 763 +               if (FD_ISSET(tls_read[1], &wd) && write2 < avail2) {
 764 +                       r = write(tls_read[1], buf2+write2, avail2-write2);
 765 +                       if (r >= 0)
 766 +                               write2 += r;
 767 +                       else {
 768 +                               rprintf(FERROR, "pipe write error: %s\n",
 769 +                                       strerror(errno));
 770 +                               break;
 771 +                       }
 772 +               }
 773 +               if (FD_ISSET(tls_fd, &wd) && write1 < avail1) {
 774 +                       r = SSL_write(ssl, buf1+write1, avail1-write1);
 775 +                       if (r > 0)
 776 +                               write1 += r;
 777 +                       else {
 778 +                               switch (SSL_get_error(ssl, r)) {
 779 +                               case SSL_ERROR_ZERO_RETURN:
 780 +                                       goto closed;
 781 +                               case SSL_ERROR_WANT_READ:
 782 +                               case SSL_ERROR_WANT_WRITE:
 783 +                                       break;
 784 +                               case SSL_ERROR_SYSCALL:
 785 +                                       if (r == 0)
 786 +                                               rprintf(FERROR, "SSL: spurious EOF\n");
 787 +                                       else
 788 +                                               rprintf(FERROR, "SSL: I/O error: %s\n",
 789 +                                                       strerror(errno));
 790 +                                       goto closed;
 791 +                               case SSL_ERROR_SSL:
 792 +                                       rprintf(FERROR, "SSL: %s\n",
 793 +                                               ERR_error_string(ERR_get_error(), NULL));
 794 +                                       goto closed;
 795 +                               default:
 796 +                                       rprintf(FERROR, "unexpected ssl error %d\n", r);
 797 +                                       goto closed;
 798 +                               }
 799 +                       }
 800 +               }
 801 +               if (avail1 == write1)
 802 +                       avail1 = write1 = 0;
 803 +               if (avail2 == write2)
 804 +                       avail2 = write2 = 0;
 805 +       }
 806 +
 807 +       /* XXX I'm pretty sure that there is a lot that I am not considering
 808 +          here. Bugs? Yes, probably. */
 809 +
 810 +       /* We're finished. */
 811 +    closed:
 812 +       close(tls_read[1]);
 813 +       close(tls_write[0]);
 814 +       exit(0);
 815 +}
 816 +
 817 +/**
 818 + * Ends the TLS connection.
 819 + */
 820 +void end_tls(void)
 821 +{
 822 +       if (ssl_pid > 0)
 823 +               kill(ssl_pid, SIGUSR1);
 824 +}