gio/gdbusauthmechanismsha1.c

   1 /* GDBus - GLib D-Bus Library
   2  *
   3  * Copyright (C) 2008-2010 Red Hat, Inc.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
  17  *
  18  * Author: David Zeuthen <davidz@redhat.com>
  19  */
  20
  21 #include "config.h"
  22
  23 #include <string.h>
  24 #include <fcntl.h>
  25 #include <errno.h>
  26 #include <sys/types.h>
  27
  28 #include <glib/gstdio.h>
  29
  30 #ifdef G_OS_UNIX
  31 #include <unistd.h>
  32 #endif
  33 #ifdef G_OS_WIN32
  34 #include <io.h>
  35 #endif
  36
  37 #include "gdbusauthmechanismsha1.h"
  38 #include "gcredentials.h"
  39 #include "gdbuserror.h"
  40 #include "gioenumtypes.h"
  41 #include "gioerror.h"
  42 #include "gdbusprivate.h"
  43
  44 #include "glibintl.h"
  45
  46 struct _GDBusAuthMechanismSha1Private
  47 {
  48   gboolean is_client;
  49   gboolean is_server;
  50   GDBusAuthMechanismState state;
  51
  52   /* used on the client side */
  53   gchar *to_send;
  54
  55   /* used on the server side */
  56   gchar *cookie;
  57   gchar *server_challenge;
  58 };
  59
  60 static gint                     mechanism_get_priority              (void);
  61 static const gchar             *mechanism_get_name                  (void);
  62
  63 static gboolean                 mechanism_is_supported              (GDBusAuthMechanism   *mechanism);
  64 static gchar                   *mechanism_encode_data               (GDBusAuthMechanism   *mechanism,
  65                                                                      const gchar          *data,
  66                                                                      gsize                 data_len,
  67                                                                      gsize                *out_data_len);
  68 static gchar                   *mechanism_decode_data               (GDBusAuthMechanism   *mechanism,
  69                                                                      const gchar          *data,
  70                                                                      gsize                 data_len,
  71                                                                      gsize                *out_data_len);
  72 static GDBusAuthMechanismState  mechanism_server_get_state          (GDBusAuthMechanism   *mechanism);
  73 static void                     mechanism_server_initiate           (GDBusAuthMechanism   *mechanism,
  74                                                                      const gchar          *initial_response,
  75                                                                      gsize                 initial_response_len);
  76 static void                     mechanism_server_data_receive       (GDBusAuthMechanism   *mechanism,
  77                                                                      const gchar          *data,
  78                                                                      gsize                 data_len);
  79 static gchar                   *mechanism_server_data_send          (GDBusAuthMechanism   *mechanism,
  80                                                                      gsize                *out_data_len);
  81 static gchar                   *mechanism_server_get_reject_reason  (GDBusAuthMechanism   *mechanism);
  82 static void                     mechanism_server_shutdown           (GDBusAuthMechanism   *mechanism);
  83 static GDBusAuthMechanismState  mechanism_client_get_state          (GDBusAuthMechanism   *mechanism);
  84 static gchar                   *mechanism_client_initiate           (GDBusAuthMechanism   *mechanism,
  85                                                                      gsize                *out_initial_response_len);
  86 static void                     mechanism_client_data_receive       (GDBusAuthMechanism   *mechanism,
  87                                                                      const gchar          *data,
  88                                                                      gsize                 data_len);
  89 static gchar                   *mechanism_client_data_send          (GDBusAuthMechanism   *mechanism,
  90                                                                      gsize                *out_data_len);
  91 static void                     mechanism_client_shutdown           (GDBusAuthMechanism   *mechanism);
  92
  93 /* ---------------------------------------------------------------------------------------------------- */
  94
  95 G_DEFINE_TYPE_WITH_PRIVATE (GDBusAuthMechanismSha1, _g_dbus_auth_mechanism_sha1, G_TYPE_DBUS_AUTH_MECHANISM)
  96
  97 /* ---------------------------------------------------------------------------------------------------- */
  98
  99 static void
 100 _g_dbus_auth_mechanism_sha1_finalize (GObject *object)
 101 {
 102   GDBusAuthMechanismSha1 *mechanism = G_DBUS_AUTH_MECHANISM_SHA1 (object);
 103
 104   g_free (mechanism->priv->to_send);
 105
 106   g_free (mechanism->priv->cookie);
 107   g_free (mechanism->priv->server_challenge);
 108
 109   if (G_OBJECT_CLASS (_g_dbus_auth_mechanism_sha1_parent_class)->finalize != NULL)
 110     G_OBJECT_CLASS (_g_dbus_auth_mechanism_sha1_parent_class)->finalize (object);
 111 }
 112
 113 static void
 114 _g_dbus_auth_mechanism_sha1_class_init (GDBusAuthMechanismSha1Class *klass)
 115 {
 116   GObjectClass *gobject_class;
 117   GDBusAuthMechanismClass *mechanism_class;
 118
 119   gobject_class = G_OBJECT_CLASS (klass);
 120   gobject_class->finalize = _g_dbus_auth_mechanism_sha1_finalize;
 121
 122   mechanism_class = G_DBUS_AUTH_MECHANISM_CLASS (klass);
 123   mechanism_class->get_priority              = mechanism_get_priority;
 124   mechanism_class->get_name                  = mechanism_get_name;
 125   mechanism_class->is_supported              = mechanism_is_supported;
 126   mechanism_class->encode_data               = mechanism_encode_data;
 127   mechanism_class->decode_data               = mechanism_decode_data;
 128   mechanism_class->server_get_state          = mechanism_server_get_state;
 129   mechanism_class->server_initiate           = mechanism_server_initiate;
 130   mechanism_class->server_data_receive       = mechanism_server_data_receive;
 131   mechanism_class->server_data_send          = mechanism_server_data_send;
 132   mechanism_class->server_get_reject_reason  = mechanism_server_get_reject_reason;
 133   mechanism_class->server_shutdown           = mechanism_server_shutdown;
 134   mechanism_class->client_get_state          = mechanism_client_get_state;
 135   mechanism_class->client_initiate           = mechanism_client_initiate;
 136   mechanism_class->client_data_receive       = mechanism_client_data_receive;
 137   mechanism_class->client_data_send          = mechanism_client_data_send;
 138   mechanism_class->client_shutdown           = mechanism_client_shutdown;
 139 }
 140
 141 static void
 142 _g_dbus_auth_mechanism_sha1_init (GDBusAuthMechanismSha1 *mechanism)
 143 {
 144   mechanism->priv = _g_dbus_auth_mechanism_sha1_get_instance_private (mechanism);
 145 }
 146
 147 /* ---------------------------------------------------------------------------------------------------- */
 148
 149 static gint
 150 mechanism_get_priority (void)
 151 {
 152   return 0;
 153 }
 154
 155 static const gchar *
 156 mechanism_get_name (void)
 157 {
 158   return "DBUS_COOKIE_SHA1";
 159 }
 160
 161 static gboolean
 162 mechanism_is_supported (GDBusAuthMechanism *mechanism)
 163 {
 164   g_return_val_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism), FALSE);
 165   return TRUE;
 166 }
 167
 168 static gchar *
 169 mechanism_encode_data (GDBusAuthMechanism   *mechanism,
 170                        const gchar          *data,
 171                        gsize                 data_len,
 172                        gsize                *out_data_len)
 173 {
 174   return NULL;
 175 }
 176
 177
 178 static gchar *
 179 mechanism_decode_data (GDBusAuthMechanism   *mechanism,
 180                        const gchar          *data,
 181                        gsize                 data_len,
 182                        gsize                *out_data_len)
 183 {
 184   return NULL;
 185 }
 186
 187 /* ---------------------------------------------------------------------------------------------------- */
 188
 189 static gint
 190 random_ascii (void)
 191 {
 192   gint ret;
 193   ret = g_random_int_range (0, 60);
 194   if (ret < 25)
 195     ret += 'A';
 196   else if (ret < 50)
 197     ret += 'a' - 25;
 198   else
 199     ret += '0' - 50;
 200   return ret;
 201 }
 202
 203 static gchar *
 204 random_ascii_string (guint len)
 205 {
 206   GString *challenge;
 207   guint n;
 208
 209   challenge = g_string_new (NULL);
 210   for (n = 0; n < len; n++)
 211     g_string_append_c (challenge, random_ascii ());
 212   return g_string_free (challenge, FALSE);
 213 }
 214
 215 static gchar *
 216 random_blob (guint len)
 217 {
 218   GString *challenge;
 219   guint n;
 220
 221   challenge = g_string_new (NULL);
 222   for (n = 0; n < len; n++)
 223     g_string_append_c (challenge, g_random_int_range (0, 256));
 224   return g_string_free (challenge, FALSE);
 225 }
 226
 227 /* ---------------------------------------------------------------------------------------------------- */
 228
 229 /* ensure keyring dir exists and permissions are correct */
 230 static gchar *
 231 ensure_keyring_directory (GError **error)
 232 {
 233   gchar *path;
 234   const gchar *e;
 235
 236   g_return_val_if_fail (error == NULL || *error == NULL, NULL);
 237
 238   e = g_getenv ("G_DBUS_COOKIE_SHA1_KEYRING_DIR");
 239   if (e != NULL)
 240     {
 241       path = g_strdup (e);
 242     }
 243   else
 244     {
 245       path = g_build_filename (g_get_home_dir (),
 246                                ".dbus-keyrings",
 247                                NULL);
 248     }
 249
 250   if (g_file_test (path, G_FILE_TEST_EXISTS | G_FILE_TEST_IS_DIR))
 251     {
 252       if (g_getenv ("G_DBUS_COOKIE_SHA1_KEYRING_DIR_IGNORE_PERMISSION") == NULL)
 253         {
 254 #ifdef G_OS_UNIX
 255           struct stat statbuf;
 256           if (stat (path, &statbuf) != 0)
 257             {
 258               g_set_error (error,
 259                            G_IO_ERROR,
 260                            g_io_error_from_errno (errno),
 261                            _("Error when getting information for directory “%s”: %s"),
 262                            path,
 263                            strerror (errno));
 264               g_free (path);
 265               path = NULL;
 266               goto out;
 267             }
 268           if ((statbuf.st_mode  & 0777) != 0700)
 269             {
 270               g_set_error (error,
 271                            G_IO_ERROR,
 272                            G_IO_ERROR_FAILED,
 273                            _("Permissions on directory “%s” are malformed. Expected mode 0700, got 0%o"),
 274                            path,
 275                            statbuf.st_mode & 0777);
 276               g_free (path);
 277               path = NULL;
 278               goto out;
 279             }
 280 #else
 281 #ifdef __GNUC__
 282 #warning Please implement permission checking on this non-UNIX platform
 283 #endif
 284 #endif
 285         }
 286         goto out;
 287     }
 288
 289   if (g_mkdir (path, 0700) != 0)
 290     {
 291       g_set_error (error,
 292                    G_IO_ERROR,
 293                    g_io_error_from_errno (errno),
 294                    _("Error creating directory “%s”: %s"),
 295                    path,
 296                    strerror (errno));
 297       g_free (path);
 298       path = NULL;
 299       goto out;
 300     }
 301
 302 out:
 303   return path;
 304 }
 305
 306 /* ---------------------------------------------------------------------------------------------------- */
 307
 308 static void
 309 append_nibble (GString *s, gint val)
 310 {
 311   g_string_append_c (s, val >= 10 ? ('a' + val - 10) : ('0' + val));
 312 }
 313
 314 static gchar *
 315 hexencode (const gchar *str,
 316            gssize       len)
 317 {
 318   guint n;
 319   GString *s;
 320
 321   if (len == -1)
 322     len = strlen (str);
 323
 324   s = g_string_new (NULL);
 325   for (n = 0; n < len; n++)
 326     {
 327       gint val;
 328       gint upper_nibble;
 329       gint lower_nibble;
 330
 331       val = ((const guchar *) str)[n];
 332       upper_nibble = val >> 4;
 333       lower_nibble = val & 0x0f;
 334
 335       append_nibble (s, upper_nibble);
 336       append_nibble (s, lower_nibble);
 337     }
 338
 339   return g_string_free (s, FALSE);
 340 }
 341
 342 /* ---------------------------------------------------------------------------------------------------- */
 343
 344 /* looks up an entry in the keyring */
 345 static gchar *
 346 keyring_lookup_entry (const gchar  *cookie_context,
 347                       gint          cookie_id,
 348                       GError      **error)
 349 {
 350   gchar *ret;
 351   gchar *keyring_dir;
 352   gchar *contents;
 353   gchar *path;
 354   guint n;
 355   gchar **lines;
 356
 357   g_return_val_if_fail (cookie_context != NULL, NULL);
 358   g_return_val_if_fail (error == NULL || *error == NULL, NULL);
 359
 360   ret = NULL;
 361   path = NULL;
 362   contents = NULL;
 363   lines = NULL;
 364
 365   keyring_dir = ensure_keyring_directory (error);
 366   if (keyring_dir == NULL)
 367     goto out;
 368
 369   path = g_build_filename (keyring_dir, cookie_context, NULL);
 370
 371   if (!g_file_get_contents (path,
 372                             &contents,
 373                             NULL,
 374                             error))
 375     {
 376       g_prefix_error (error,
 377                       _("Error opening keyring “%s” for reading: "),
 378                       path);
 379       goto out;
 380     }
 381   g_assert (contents != NULL);
 382
 383   lines = g_strsplit (contents, "\n", 0);
 384   for (n = 0; lines[n] != NULL; n++)
 385     {
 386       const gchar *line = lines[n];
 387       gchar **tokens;
 388       gchar *endp;
 389       gint line_id;
 390       guint64 line_when;
 391
 392       if (line[0] == '\0')
 393         continue;
 394
 395       tokens = g_strsplit (line, " ", 0);
 396       if (g_strv_length (tokens) != 3)
 397         {
 398           g_set_error (error,
 399                        G_IO_ERROR,
 400                        G_IO_ERROR_FAILED,
 401                        _("Line %d of the keyring at “%s” with content “%s” is malformed"),
 402                        n + 1,
 403                        path,
 404                        line);
 405           g_strfreev (tokens);
 406           goto out;
 407         }
 408
 409       line_id = g_ascii_strtoll (tokens[0], &endp, 10);
 410       if (*endp != '\0')
 411         {
 412           g_set_error (error,
 413                        G_IO_ERROR,
 414                        G_IO_ERROR_FAILED,
 415                        _("First token of line %d of the keyring at “%s” with content “%s” is malformed"),
 416                        n + 1,
 417                        path,
 418                        line);
 419           g_strfreev (tokens);
 420           goto out;
 421         }
 422
 423       line_when = g_ascii_strtoll (tokens[1], &endp, 10);
 424       line_when = line_when; /* To avoid -Wunused-but-set-variable */
 425       if (*endp != '\0')
 426         {
 427           g_set_error (error,
 428                        G_IO_ERROR,
 429                        G_IO_ERROR_FAILED,
 430                        _("Second token of line %d of the keyring at “%s” with content “%s” is malformed"),
 431                        n + 1,
 432                        path,
 433                        line);
 434           g_strfreev (tokens);
 435           goto out;
 436         }
 437
 438       if (line_id == cookie_id)
 439         {
 440           /* YAY, success */
 441           ret = tokens[2]; /* steal pointer */
 442           tokens[2] = NULL;
 443           g_strfreev (tokens);
 444           goto out;
 445         }
 446
 447       g_strfreev (tokens);
 448     }
 449
 450   /* BOOH, didn't find the cookie */
 451   g_set_error (error,
 452                G_IO_ERROR,
 453                G_IO_ERROR_FAILED,
 454                _("Didn’t find cookie with id %d in the keyring at “%s”"),
 455                cookie_id,
 456                path);
 457
 458  out:
 459   g_free (keyring_dir);
 460   g_free (path);
 461   g_free (contents);
 462   g_strfreev (lines);
 463   return ret;
 464 }
 465
 466 /* function for logging important events that the system administrator should take notice of */
 467 G_GNUC_PRINTF(1, 2)
 468 static void
 469 _log (const gchar *message,
 470       ...)
 471 {
 472   gchar *s;
 473   va_list var_args;
 474
 475   va_start (var_args, message);
 476   s = g_strdup_vprintf (message, var_args);
 477   va_end (var_args);
 478
 479   /* TODO: might want to send this to syslog instead */
 480   g_printerr ("GDBus-DBUS_COOKIE_SHA1: %s\n", s);
 481   g_free (s);
 482 }
 483
 484 static gint
 485 keyring_acquire_lock (const gchar  *path,
 486                       GError      **error)
 487 {
 488   gchar *lock;
 489   gint ret;
 490   guint num_tries;
 491   guint num_create_tries;
 492
 493   g_return_val_if_fail (path != NULL, FALSE);
 494   g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
 495
 496   ret = -1;
 497   lock = g_strdup_printf ("%s.lock", path);
 498
 499   /* This is what the D-Bus spec says
 500    *
 501    *  Create a lockfile name by appending ".lock" to the name of the
 502    *  cookie file. The server should attempt to create this file using
 503    *  O_CREAT | O_EXCL. If file creation fails, the lock
 504    *  fails. Servers should retry for a reasonable period of time,
 505    *  then they may choose to delete an existing lock to keep users
 506    *  from having to manually delete a stale lock. [1]
 507    *
 508    *  [1] : Lockfiles are used instead of real file locking fcntl() because
 509    *         real locking implementations are still flaky on network filesystems
 510    */
 511
 512   num_create_tries = 0;
 513 #ifdef EEXISTS
 514  again:
 515 #endif
 516   num_tries = 0;
 517   while (g_file_test (lock, G_FILE_TEST_EXISTS))
 518     {
 519       /* sleep 10ms, then try again */
 520       g_usleep (1000*10);
 521       num_tries++;
 522       if (num_tries == 50)
 523         {
 524           /* ok, we slept 50*10ms = 0.5 seconds. Conclude that the lock file must be
 525            * stale (nuke the it from orbit)
 526            */
 527           if (g_unlink (lock) != 0)
 528             {
 529               g_set_error (error,
 530                            G_IO_ERROR,
 531                            g_io_error_from_errno (errno),
 532                            _("Error deleting stale lock file “%s”: %s"),
 533                            lock,
 534                            strerror (errno));
 535               goto out;
 536             }
 537           _log ("Deleted stale lock file '%s'", lock);
 538           break;
 539         }
 540     }
 541
 542   ret = g_open (lock, O_CREAT |
 543 #ifdef O_EXCL
 544                 O_EXCL,
 545 #else
 546                 0,
 547 #endif
 548                 0700);
 549   if (ret == -1)
 550     {
 551 #ifdef EEXISTS
 552       /* EEXIST: pathname already exists and O_CREAT and O_EXCL were used. */
 553       if (errno == EEXISTS)
 554         {
 555           num_create_tries++;
 556           if (num_create_tries < 5)
 557             goto again;
 558         }
 559 #endif
 560       num_create_tries = num_create_tries; /* To avoid -Wunused-but-set-variable */
 561       g_set_error (error,
 562                    G_IO_ERROR,
 563                    g_io_error_from_errno (errno),
 564                    _("Error creating lock file “%s”: %s"),
 565                    lock,
 566                    strerror (errno));
 567       goto out;
 568     }
 569
 570  out:
 571   g_free (lock);
 572   return ret;
 573 }
 574
 575 static gboolean
 576 keyring_release_lock (const gchar  *path,
 577                       gint          lock_fd,
 578                       GError      **error)
 579 {
 580   gchar *lock;
 581   gboolean ret;
 582
 583   g_return_val_if_fail (path != NULL, FALSE);
 584   g_return_val_if_fail (lock_fd != -1, FALSE);
 585   g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
 586
 587   ret = FALSE;
 588   lock = g_strdup_printf ("%s.lock", path);
 589   if (close (lock_fd) != 0)
 590     {
 591       g_set_error (error,
 592                    G_IO_ERROR,
 593                    g_io_error_from_errno (errno),
 594                    _("Error closing (unlinked) lock file “%s”: %s"),
 595                    lock,
 596                    strerror (errno));
 597       goto out;
 598     }
 599   if (g_unlink (lock) != 0)
 600     {
 601       g_set_error (error,
 602                    G_IO_ERROR,
 603                    g_io_error_from_errno (errno),
 604                    _("Error unlinking lock file “%s”: %s"),
 605                    lock,
 606                    strerror (errno));
 607       goto out;
 608     }
 609
 610   ret = TRUE;
 611
 612  out:
 613   g_free (lock);
 614   return ret;
 615 }
 616
 617
 618 /* adds an entry to the keyring, taking care of locking and deleting stale/future entries */
 619 static gboolean
 620 keyring_generate_entry (const gchar  *cookie_context,
 621                         gint         *out_id,
 622                         gchar       **out_cookie,
 623                         GError      **error)
 624 {
 625   gboolean ret;
 626   gchar *keyring_dir;
 627   gchar *path;
 628   gchar *contents;
 629   GError *local_error;
 630   gchar **lines;
 631   gint max_line_id;
 632   GString *new_contents;
 633   guint64 now;
 634   gboolean have_id;
 635   gint use_id;
 636   gchar *use_cookie;
 637   gboolean changed_file;
 638   gint lock_fd;
 639
 640   g_return_val_if_fail (cookie_context != NULL, FALSE);
 641   g_return_val_if_fail (out_id != NULL, FALSE);
 642   g_return_val_if_fail (out_cookie != NULL, FALSE);
 643   g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
 644
 645   ret = FALSE;
 646   path = NULL;
 647   contents = NULL;
 648   lines = NULL;
 649   new_contents = NULL;
 650   have_id = FALSE;
 651   use_id = 0;
 652   use_cookie = NULL;
 653   lock_fd = -1;
 654
 655   keyring_dir = ensure_keyring_directory (error);
 656   if (keyring_dir == NULL)
 657     goto out;
 658
 659   path = g_build_filename (keyring_dir, cookie_context, NULL);
 660
 661   lock_fd = keyring_acquire_lock (path, error);
 662   if (lock_fd == -1)
 663     goto out;
 664
 665   local_error = NULL;
 666   contents = NULL;
 667   if (!g_file_get_contents (path,
 668                             &contents,
 669                             NULL,
 670                             &local_error))
 671     {
 672       if (local_error->domain == G_FILE_ERROR && local_error->code == G_FILE_ERROR_NOENT)
 673         {
 674           /* file doesn't have to exist */
 675           g_error_free (local_error);
 676         }
 677       else
 678         {
 679           g_propagate_prefixed_error (error,
 680                                       local_error,
 681                                       _("Error opening keyring “%s” for writing: "),
 682                                       path);
 683           goto out;
 684         }
 685     }
 686
 687   new_contents = g_string_new (NULL);
 688   now = time (NULL);
 689   changed_file = FALSE;
 690
 691   max_line_id = 0;
 692   if (contents != NULL)
 693     {
 694       guint n;
 695       lines = g_strsplit (contents, "\n", 0);
 696       for (n = 0; lines[n] != NULL; n++)
 697         {
 698           const gchar *line = lines[n];
 699           gchar **tokens;
 700           gchar *endp;
 701           gint line_id;
 702           guint64 line_when;
 703           gboolean keep_entry;
 704
 705           if (line[0] == '\0')
 706             continue;
 707
 708           tokens = g_strsplit (line, " ", 0);
 709           if (g_strv_length (tokens) != 3)
 710             {
 711               g_set_error (error,
 712                            G_IO_ERROR,
 713                            G_IO_ERROR_FAILED,
 714                            _("Line %d of the keyring at “%s” with content “%s” is malformed"),
 715                            n + 1,
 716                            path,
 717                            line);
 718               g_strfreev (tokens);
 719               goto out;
 720             }
 721
 722           line_id = g_ascii_strtoll (tokens[0], &endp, 10);
 723           if (*endp != '\0')
 724             {
 725               g_set_error (error,
 726                            G_IO_ERROR,
 727                            G_IO_ERROR_FAILED,
 728                            _("First token of line %d of the keyring at “%s” with content “%s” is malformed"),
 729                            n + 1,
 730                            path,
 731                            line);
 732               g_strfreev (tokens);
 733               goto out;
 734             }
 735
 736           line_when = g_ascii_strtoll (tokens[1], &endp, 10);
 737           if (*endp != '\0')
 738             {
 739               g_set_error (error,
 740                            G_IO_ERROR,
 741                            G_IO_ERROR_FAILED,
 742                            _("Second token of line %d of the keyring at “%s” with content “%s” is malformed"),
 743                            n + 1,
 744                            path,
 745                            line);
 746               g_strfreev (tokens);
 747               goto out;
 748             }
 749           line_when = line_when; /* To avoid -Wunused-but-set-variable */
 750
 751
 752           /* D-Bus spec says:
 753            *
 754            *  Once the lockfile has been created, the server loads the
 755            *  cookie file. It should then delete any cookies that are
 756            *  old (the timeout can be fairly short), or more than a
 757            *  reasonable time in the future (so that cookies never
 758            *  accidentally become permanent, if the clock was set far
 759            *  into the future at some point). If no recent keys remain,
 760            *  the server may generate a new key.
 761            *
 762            */
 763           keep_entry = TRUE;
 764           if (line_when > now)
 765             {
 766               /* Oddball case: entry is more recent than our current wall-clock time..
 767                * This is OK, it means that another server on another machine but with
 768                * same $HOME wrote the entry.
 769                *
 770                * So discard the entry if it's more than 1 day in the future ("reasonable
 771                * time in the future").
 772                */
 773               if (line_when - now > 24*60*60)
 774                 {
 775                   keep_entry = FALSE;
 776                   _log ("Deleted SHA1 cookie from %" G_GUINT64_FORMAT " seconds in the future", line_when - now);
 777                 }
 778             }
 779           else
 780             {
 781               /* Discard entry if it's older than 15 minutes ("can be fairly short") */
 782               if (now - line_when > 15*60)
 783                 {
 784                   keep_entry = FALSE;
 785                 }
 786             }
 787
 788           if (!keep_entry)
 789             {
 790               changed_file = FALSE;
 791             }
 792           else
 793             {
 794               g_string_append_printf (new_contents,
 795                                       "%d %" G_GUINT64_FORMAT " %s\n",
 796                                       line_id,
 797                                       line_when,
 798                                       tokens[2]);
 799               max_line_id = MAX (line_id, max_line_id);
 800               /* Only reuse entry if not older than 10 minutes.
 801                *
 802                * (We need a bit of grace time compared to 15 minutes above.. otherwise
 803                * there's a race where we reuse the 14min59.9 secs old entry and a
 804                * split-second later another server purges the now 15 minute old entry.)
 805                */
 806               if (now - line_when < 10 * 60)
 807                 {
 808                   if (!have_id)
 809                     {
 810                       use_id = line_id;
 811                       use_cookie = tokens[2]; /* steal memory */
 812                       tokens[2] = NULL;
 813                       have_id = TRUE;
 814                     }
 815                 }
 816             }
 817           g_strfreev (tokens);
 818         }
 819     } /* for each line */
 820
 821   ret = TRUE;
 822
 823   if (have_id)
 824     {
 825       *out_id = use_id;
 826       *out_cookie = use_cookie;
 827       use_cookie = NULL;
 828     }
 829   else
 830     {
 831       gchar *raw_cookie;
 832       *out_id = max_line_id + 1;
 833       raw_cookie = random_blob (32);
 834       *out_cookie = hexencode (raw_cookie, 32);
 835       g_free (raw_cookie);
 836
 837       g_string_append_printf (new_contents,
 838                               "%d %" G_GUINT64_FORMAT " %s\n",
 839                               *out_id,
 840                               (guint64) time (NULL),
 841                               *out_cookie);
 842       changed_file = TRUE;
 843     }
 844
 845   /* and now actually write the cookie file if there are changes (this is atomic) */
 846   if (changed_file)
 847     {
 848       if (!g_file_set_contents (path,
 849                                 new_contents->str,
 850                                 -1,
 851                                 error))
 852         {
 853           *out_id = 0;
 854           *out_cookie = 0;
 855           g_free (*out_cookie);
 856           ret = FALSE;
 857           goto out;
 858         }
 859     }
 860
 861  out:
 862
 863   if (lock_fd != -1)
 864     {
 865       GError *local_error;
 866       local_error = NULL;
 867       if (!keyring_release_lock (path, lock_fd, &local_error))
 868         {
 869           if (error != NULL)
 870             {
 871               if (*error == NULL)
 872                 {
 873                   *error = local_error;
 874                 }
 875               else
 876                 {
 877                   g_prefix_error (error,
 878                                   _("(Additionally, releasing the lock for “%s” also failed: %s) "),
 879                                   path,
 880                                   local_error->message);
 881                 }
 882             }
 883           else
 884             {
 885               g_error_free (local_error);
 886             }
 887         }
 888     }
 889
 890   g_free (keyring_dir);
 891   g_free (path);
 892   g_strfreev (lines);
 893   g_free (contents);
 894   if (new_contents != NULL)
 895     g_string_free (new_contents, TRUE);
 896   g_free (use_cookie);
 897   return ret;
 898 }
 899
 900 /* ---------------------------------------------------------------------------------------------------- */
 901
 902 static gchar *
 903 generate_sha1 (const gchar *server_challenge,
 904                const gchar *client_challenge,
 905                const gchar *cookie)
 906 {
 907   GString *str;
 908   gchar *sha1;
 909
 910   str = g_string_new (server_challenge);
 911   g_string_append_c (str, ':');
 912   g_string_append (str, client_challenge);
 913   g_string_append_c (str, ':');
 914   g_string_append (str, cookie);
 915   sha1 = g_compute_checksum_for_string (G_CHECKSUM_SHA1, str->str, -1);
 916   g_string_free (str, TRUE);
 917
 918   return sha1;
 919 }
 920
 921 /* ---------------------------------------------------------------------------------------------------- */
 922
 923 static GDBusAuthMechanismState
 924 mechanism_server_get_state (GDBusAuthMechanism   *mechanism)
 925 {
 926   GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
 927
 928   g_return_val_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism), G_DBUS_AUTH_MECHANISM_STATE_INVALID);
 929   g_return_val_if_fail (m->priv->is_server && !m->priv->is_client, G_DBUS_AUTH_MECHANISM_STATE_INVALID);
 930
 931   return m->priv->state;
 932 }
 933
 934 static void
 935 mechanism_server_initiate (GDBusAuthMechanism   *mechanism,
 936                            const gchar          *initial_response,
 937                            gsize                 initial_response_len)
 938 {
 939   GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
 940
 941   g_return_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism));
 942   g_return_if_fail (!m->priv->is_server && !m->priv->is_client);
 943
 944   m->priv->is_server = TRUE;
 945   m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_REJECTED;
 946
 947   if (initial_response != NULL && strlen (initial_response) > 0)
 948     {
 949 #ifdef G_OS_UNIX
 950       gint64 uid;
 951       gchar *endp;
 952
 953       uid = g_ascii_strtoll (initial_response, &endp, 10);
 954       if (*endp == '\0')
 955         {
 956           if (uid == getuid ())
 957             {
 958               m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_HAVE_DATA_TO_SEND;
 959             }
 960         }
 961 #elif defined(G_OS_WIN32)
 962       gchar *sid;
 963       sid = _g_dbus_win32_get_user_sid ();
 964       if (g_strcmp0 (initial_response, sid) == 0)
 965         m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_HAVE_DATA_TO_SEND;
 966       g_free (sid);
 967 #else
 968 #error Please implement for your OS
 969 #endif
 970     }
 971 }
 972
 973 static void
 974 mechanism_server_data_receive (GDBusAuthMechanism   *mechanism,
 975                                const gchar          *data,
 976                                gsize                 data_len)
 977 {
 978   GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
 979   gchar **tokens;
 980   const gchar *client_challenge;
 981   const gchar *alleged_sha1;
 982   gchar *sha1;
 983
 984   g_return_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism));
 985   g_return_if_fail (m->priv->is_server && !m->priv->is_client);
 986   g_return_if_fail (m->priv->state == G_DBUS_AUTH_MECHANISM_STATE_WAITING_FOR_DATA);
 987
 988   tokens = NULL;
 989   sha1 = NULL;
 990
 991   tokens = g_strsplit (data, " ", 0);
 992   if (g_strv_length (tokens) != 2)
 993     {
 994       g_warning ("Malformed data '%s'", data);
 995       m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_REJECTED;
 996       goto out;
 997     }
 998
 999   client_challenge = tokens[0];
1000   alleged_sha1 = tokens[1];
1001
1002   sha1 = generate_sha1 (m->priv->server_challenge, client_challenge, m->priv->cookie);
1003
1004   if (g_strcmp0 (sha1, alleged_sha1) == 0)
1005     {
1006       m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_ACCEPTED;
1007     }
1008   else
1009     {
1010       m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_REJECTED;
1011     }
1012
1013  out:
1014   g_strfreev (tokens);
1015   g_free (sha1);
1016 }
1017
1018 static gchar *
1019 mechanism_server_data_send (GDBusAuthMechanism   *mechanism,
1020                             gsize                *out_data_len)
1021 {
1022   GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
1023   gchar *s;
1024   gint cookie_id;
1025   const gchar *cookie_context;
1026   GError *error;
1027
1028   g_return_val_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism), NULL);
1029   g_return_val_if_fail (m->priv->is_server && !m->priv->is_client, NULL);
1030   g_return_val_if_fail (m->priv->state == G_DBUS_AUTH_MECHANISM_STATE_HAVE_DATA_TO_SEND, NULL);
1031
1032   s = NULL;
1033
1034   /* TODO: use GDBusAuthObserver here to get the cookie context to use? */
1035   cookie_context = "org_gtk_gdbus_general";
1036
1037   cookie_id = -1;
1038   error = NULL;
1039   if (!keyring_generate_entry (cookie_context,
1040                                &cookie_id,
1041                                &m->priv->cookie,
1042                                &error))
1043     {
1044       g_warning ("Error adding entry to keyring: %s", error->message);
1045       g_error_free (error);
1046       m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_REJECTED;
1047       goto out;
1048     }
1049
1050   m->priv->server_challenge = random_ascii_string (16);
1051   s = g_strdup_printf ("%s %d %s",
1052                        cookie_context,
1053                        cookie_id,
1054                        m->priv->server_challenge);
1055
1056   m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_WAITING_FOR_DATA;
1057
1058  out:
1059   return s;
1060 }
1061
1062 static gchar *
1063 mechanism_server_get_reject_reason (GDBusAuthMechanism   *mechanism)
1064 {
1065   GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
1066
1067   g_return_val_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism), NULL);
1068   g_return_val_if_fail (m->priv->is_server && !m->priv->is_client, NULL);
1069   g_return_val_if_fail (m->priv->state == G_DBUS_AUTH_MECHANISM_STATE_REJECTED, NULL);
1070
1071   /* can never end up here because we are never in the REJECTED state */
1072   g_assert_not_reached ();
1073
1074   return NULL;
1075 }
1076
1077 static void
1078 mechanism_server_shutdown (GDBusAuthMechanism   *mechanism)
1079 {
1080   GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
1081
1082   g_return_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism));
1083   g_return_if_fail (m->priv->is_server && !m->priv->is_client);
1084
1085   m->priv->is_server = FALSE;
1086 }
1087
1088 /* ---------------------------------------------------------------------------------------------------- */
1089
1090 static GDBusAuthMechanismState
1091 mechanism_client_get_state (GDBusAuthMechanism   *mechanism)
1092 {
1093   GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
1094
1095   g_return_val_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism), G_DBUS_AUTH_MECHANISM_STATE_INVALID);
1096   g_return_val_if_fail (m->priv->is_client && !m->priv->is_server, G_DBUS_AUTH_MECHANISM_STATE_INVALID);
1097
1098   return m->priv->state;
1099 }
1100
1101 static gchar *
1102 mechanism_client_initiate (GDBusAuthMechanism   *mechanism,
1103                            gsize                *out_initial_response_len)
1104 {
1105   GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
1106   gchar *initial_response;
1107
1108   g_return_val_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism), NULL);
1109   g_return_val_if_fail (!m->priv->is_server && !m->priv->is_client, NULL);
1110
1111   m->priv->is_client = TRUE;
1112   m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_WAITING_FOR_DATA;
1113
1114   *out_initial_response_len = -1;
1115
1116 #ifdef G_OS_UNIX
1117   initial_response = g_strdup_printf ("%" G_GINT64_FORMAT, (gint64) getuid ());
1118 #elif defined (G_OS_WIN32)
1119 initial_response = _g_dbus_win32_get_user_sid ();
1120 #else
1121 #error Please implement for your OS
1122 #endif
1123   g_assert (initial_response != NULL);
1124
1125   return initial_response;
1126 }
1127
1128 static void
1129 mechanism_client_data_receive (GDBusAuthMechanism   *mechanism,
1130                                const gchar          *data,
1131                                gsize                 data_len)
1132 {
1133   GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
1134   gchar **tokens;
1135   const gchar *cookie_context;
1136   guint cookie_id;
1137   const gchar *server_challenge;
1138   gchar *client_challenge;
1139   gchar *endp;
1140   gchar *cookie;
1141   GError *error;
1142   gchar *sha1;
1143
1144   g_return_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism));
1145   g_return_if_fail (m->priv->is_client && !m->priv->is_server);
1146   g_return_if_fail (m->priv->state == G_DBUS_AUTH_MECHANISM_STATE_WAITING_FOR_DATA);
1147
1148   tokens = NULL;
1149   cookie = NULL;
1150   client_challenge = NULL;
1151
1152   tokens = g_strsplit (data, " ", 0);
1153   if (g_strv_length (tokens) != 3)
1154     {
1155       g_warning ("Malformed data '%s'", data);
1156       m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_REJECTED;
1157       goto out;
1158     }
1159
1160   cookie_context = tokens[0];
1161   cookie_id = g_ascii_strtoll (tokens[1], &endp, 10);
1162   if (*endp != '\0')
1163     {
1164       g_warning ("Malformed cookie_id '%s'", tokens[1]);
1165       m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_REJECTED;
1166       goto out;
1167     }
1168   server_challenge = tokens[2];
1169
1170   error = NULL;
1171   cookie = keyring_lookup_entry (cookie_context, cookie_id, &error);
1172   if (cookie == NULL)
1173     {
1174       g_warning ("Problems looking up entry in keyring: %s", error->message);
1175       g_error_free (error);
1176       m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_REJECTED;
1177       goto out;
1178     }
1179
1180   client_challenge = random_ascii_string (16);
1181   sha1 = generate_sha1 (server_challenge, client_challenge, cookie);
1182   m->priv->to_send = g_strdup_printf ("%s %s", client_challenge, sha1);
1183   g_free (sha1);
1184   m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_HAVE_DATA_TO_SEND;
1185
1186  out:
1187   g_strfreev (tokens);
1188   g_free (cookie);
1189   g_free (client_challenge);
1190 }
1191
1192 static gchar *
1193 mechanism_client_data_send (GDBusAuthMechanism   *mechanism,
1194                             gsize                *out_data_len)
1195 {
1196   GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
1197
1198   g_return_val_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism), NULL);
1199   g_return_val_if_fail (m->priv->is_client && !m->priv->is_server, NULL);
1200   g_return_val_if_fail (m->priv->state == G_DBUS_AUTH_MECHANISM_STATE_HAVE_DATA_TO_SEND, NULL);
1201
1202   g_assert (m->priv->to_send != NULL);
1203
1204   m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_ACCEPTED;
1205
1206   return g_strdup (m->priv->to_send);
1207 }
1208
1209 static void
1210 mechanism_client_shutdown (GDBusAuthMechanism   *mechanism)
1211 {
1212   GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
1213
1214   g_return_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism));
1215   g_return_if_fail (m->priv->is_client && !m->priv->is_server);
1216
1217   m->priv->is_client = FALSE;
1218 }
1219
1220 /* ---------------------------------------------------------------------------------------------------- */