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|---|---|---|---|
| 1 | /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- | ||
| 2 | * | ||
| 3 | * Copyright © 2018 Endless Mobile, Inc. | ||
| 4 | * | ||
| 5 | * SPDX-License-Identifier: LGPL-2.1-or-later | ||
| 6 | * | ||
| 7 | * This library is free software; you can redistribute it and/or | ||
| 8 | * modify it under the terms of the GNU Lesser General Public | ||
| 9 | * License as published by the Free Software Foundation; either | ||
| 10 | * version 2.1 of the License, or (at your option) any later version. | ||
| 11 | * | ||
| 12 | * This library is distributed in the hope that it will be useful, | ||
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
| 15 | * Lesser General Public License for more details. | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU Lesser General Public | ||
| 18 | * License along with this library; if not, write to the Free Software | ||
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | ||
| 20 | * | ||
| 21 | * Authors: | ||
| 22 | * - Philip Withnall <withnall@endlessm.com> | ||
| 23 | */ | ||
| 24 | |||
| 25 | #include "config.h" | ||
| 26 | |||
| 27 | #include <glib.h> | ||
| 28 | #include <glib-object.h> | ||
| 29 | #include <glib/gi18n-lib.h> | ||
| 30 | #include <gio/gio.h> | ||
| 31 | #include <libgsystemservice/peer-manager.h> | ||
| 32 | #include <libgsystemservice/peer-manager-dbus.h> | ||
| 33 | #include <stdlib.h> | ||
| 34 | |||
| 35 | |||
| 36 | /** | ||
| 37 | * SECTION:peer-manager-dbus | ||
| 38 | * @short_description: D-Bus peer management and notification (implementation) | ||
| 39 | * @stability: Stable | ||
| 40 | * @include: libgsystemservice/peer-manager-dbus.h | ||
| 41 | * | ||
| 42 | * An implementation of the #GssPeerManager interface which draws its data | ||
| 43 | * from the D-Bus daemon. This is the only expected runtime implementation of | ||
| 44 | * the interface, and has only been split out from the interface to allow for | ||
| 45 | * easier unit testing of anything which uses it. | ||
| 46 | * | ||
| 47 | * The credentials of a peer are retrieved from the D-Bus daemon using | ||
| 48 | * [`GetConnectionCredentials`](https://dbus.freedesktop.org/doc/dbus-specification.html#bus-messages-get-connection-credentials), | ||
| 49 | * and reading `/proc/$pid/cmdline` to get the absolute path to the executable | ||
| 50 | * for each peer, which we use as an identifier for it. This is not atomic or | ||
| 51 | * particularly trusted, as PIDs can be reused in the time it takes us to query | ||
| 52 | * the information, and processes can modify their own cmdline file, but | ||
| 53 | * without an LSM enabled in the kernel and dbus-daemon, it’s the best we can do | ||
| 54 | * for identifying processes. | ||
| 55 | * | ||
| 56 | * Since: 0.1.0 | ||
| 57 | */ | ||
| 58 | |||
| 59 | static void gss_peer_manager_dbus_peer_manager_init (GssPeerManagerInterface *iface); | ||
| 60 | static void gss_peer_manager_dbus_dispose (GObject *object); | ||
| 61 | |||
| 62 | static void gss_peer_manager_dbus_get_property (GObject *object, | ||
| 63 | guint property_id, | ||
| 64 | GValue *value, | ||
| 65 | GParamSpec *pspec); | ||
| 66 | static void gss_peer_manager_dbus_set_property (GObject *object, | ||
| 67 | guint property_id, | ||
| 68 | const GValue *value, | ||
| 69 | GParamSpec *pspec); | ||
| 70 | |||
| 71 | static void gss_peer_manager_dbus_ensure_peer_credentials_async (GssPeerManager *manager, | ||
| 72 | const gchar *sender, | ||
| 73 | GCancellable *cancellable, | ||
| 74 | GAsyncReadyCallback callback, | ||
| 75 | gpointer user_data); | ||
| 76 | static gchar *gss_peer_manager_dbus_ensure_peer_credentials_finish (GssPeerManager *manager, | ||
| 77 | GAsyncResult *result, | ||
| 78 | GError **error); | ||
| 79 | static const gchar *gss_peer_manager_dbus_get_peer_credentials (GssPeerManager *manager, | ||
| 80 | const gchar *sender); | ||
| 81 | |||
| 82 | /** | ||
| 83 | * GssPeerManagerDBus: | ||
| 84 | * | ||
| 85 | * An implementation of #GssPeerManager. | ||
| 86 | * | ||
| 87 | * Since: 0.1.0 | ||
| 88 | */ | ||
| 89 | struct _GssPeerManagerDBus | ||
| 90 | { | ||
| 91 | GObject parent; | ||
| 92 | |||
| 93 | GDBusConnection *connection; /* (owned) */ | ||
| 94 | |||
| 95 | /* Hold the watch IDs of all peers who have added entries at some point. */ | ||
| 96 | GPtrArray *peer_watch_ids; /* (owned) */ | ||
| 97 | |||
| 98 | /* Cache of peer credentials (currently only the executable path of each peer). */ | ||
| 99 | GHashTable *peer_credentials; /* (owned) (element-type utf8 filename) */ | ||
| 100 | }; | ||
| 101 | |||
| 102 | typedef enum | ||
| 103 | { | ||
| 104 | PROP_CONNECTION = 1, | ||
| 105 | } GssPeerManagerDBusProperty; | ||
| 106 | |||
| 107 |
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12 | G_DEFINE_TYPE_WITH_CODE (GssPeerManagerDBus, gss_peer_manager_dbus, G_TYPE_OBJECT, |
| 108 | G_IMPLEMENT_INTERFACE (GSS_TYPE_PEER_MANAGER, | ||
| 109 | gss_peer_manager_dbus_peer_manager_init)) | ||
| 110 | static void | ||
| 111 | 1 | gss_peer_manager_dbus_class_init (GssPeerManagerDBusClass *klass) | |
| 112 | { | ||
| 113 | 1 | GObjectClass *object_class = (GObjectClass *) klass; | |
| 114 | 1 | GParamSpec *props[PROP_CONNECTION + 1] = { NULL, }; | |
| 115 | |||
| 116 | 1 | object_class->dispose = gss_peer_manager_dbus_dispose; | |
| 117 | 1 | object_class->get_property = gss_peer_manager_dbus_get_property; | |
| 118 | 1 | object_class->set_property = gss_peer_manager_dbus_set_property; | |
| 119 | |||
| 120 | /** | ||
| 121 | * GssPeerManagerDBus:connection: | ||
| 122 | * | ||
| 123 | * D-Bus connection to use for retrieving peer credentials. | ||
| 124 | * | ||
| 125 | * Since: 0.1.0 | ||
| 126 | */ | ||
| 127 | 1 | props[PROP_CONNECTION] = | |
| 128 | 1 | g_param_spec_object ("connection", "Connection", | |
| 129 | "D-Bus connection to use for retrieving peer credentials.", | ||
| 130 | G_TYPE_DBUS_CONNECTION, | ||
| 131 | G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS); | ||
| 132 | |||
| 133 | 1 | g_object_class_install_properties (object_class, G_N_ELEMENTS (props), props); | |
| 134 | 1 | } | |
| 135 | |||
| 136 | static void | ||
| 137 | 1 | gss_peer_manager_dbus_peer_manager_init (GssPeerManagerInterface *iface) | |
| 138 | { | ||
| 139 | 1 | iface->ensure_peer_credentials_async = gss_peer_manager_dbus_ensure_peer_credentials_async; | |
| 140 | 1 | iface->ensure_peer_credentials_finish = gss_peer_manager_dbus_ensure_peer_credentials_finish; | |
| 141 | 1 | iface->get_peer_credentials = gss_peer_manager_dbus_get_peer_credentials; | |
| 142 | 1 | } | |
| 143 | |||
| 144 | static void | ||
| 145 | ✗ | watcher_id_free (gpointer data) | |
| 146 | { | ||
| 147 | ✗ | g_bus_unwatch_name (GPOINTER_TO_UINT (data)); | |
| 148 | ✗ | } | |
| 149 | |||
| 150 | static void | ||
| 151 | 1 | gss_peer_manager_dbus_init (GssPeerManagerDBus *self) | |
| 152 | { | ||
| 153 | 1 | self->peer_watch_ids = g_ptr_array_new_with_free_func (watcher_id_free); | |
| 154 | 1 | self->peer_credentials = g_hash_table_new_full (g_str_hash, g_str_equal, | |
| 155 | g_free, g_free); | ||
| 156 | 1 | } | |
| 157 | |||
| 158 | static void | ||
| 159 | 1 | gss_peer_manager_dbus_dispose (GObject *object) | |
| 160 | { | ||
| 161 | 1 | GssPeerManagerDBus *self = GSS_PEER_MANAGER_DBUS (object); | |
| 162 | |||
| 163 |
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1 | g_clear_object (&self->connection); |
| 164 | |||
| 165 |
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1 | g_clear_pointer (&self->peer_credentials, g_hash_table_unref); |
| 166 |
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1 | g_clear_pointer (&self->peer_watch_ids, g_ptr_array_unref); |
| 167 | |||
| 168 | /* Chain up to the parent class */ | ||
| 169 | 1 | G_OBJECT_CLASS (gss_peer_manager_dbus_parent_class)->dispose (object); | |
| 170 | 1 | } | |
| 171 | |||
| 172 | static void | ||
| 173 | ✗ | gss_peer_manager_dbus_get_property (GObject *object, | |
| 174 | guint property_id, | ||
| 175 | GValue *value, | ||
| 176 | GParamSpec *pspec) | ||
| 177 | { | ||
| 178 | ✗ | GssPeerManagerDBus *self = GSS_PEER_MANAGER_DBUS (object); | |
| 179 | |||
| 180 | ✗ | switch ((GssPeerManagerDBusProperty) property_id) | |
| 181 | { | ||
| 182 | ✗ | case PROP_CONNECTION: | |
| 183 | ✗ | g_value_set_object (value, self->connection); | |
| 184 | ✗ | break; | |
| 185 | ✗ | default: | |
| 186 | ✗ | g_assert_not_reached (); | |
| 187 | } | ||
| 188 | ✗ | } | |
| 189 | |||
| 190 | static void | ||
| 191 | 1 | gss_peer_manager_dbus_set_property (GObject *object, | |
| 192 | guint property_id, | ||
| 193 | const GValue *value, | ||
| 194 | GParamSpec *pspec) | ||
| 195 | { | ||
| 196 | 1 | GssPeerManagerDBus *self = GSS_PEER_MANAGER_DBUS (object); | |
| 197 | |||
| 198 |
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1 | switch ((GssPeerManagerDBusProperty) property_id) |
| 199 | { | ||
| 200 | 1 | case PROP_CONNECTION: | |
| 201 | /* Construct only. */ | ||
| 202 |
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1 | g_assert (self->connection == NULL); |
| 203 | 1 | self->connection = g_value_dup_object (value); | |
| 204 | 1 | break; | |
| 205 | ✗ | default: | |
| 206 | ✗ | g_assert_not_reached (); | |
| 207 | } | ||
| 208 | 1 | } | |
| 209 | |||
| 210 | static void | ||
| 211 | ✗ | peer_vanished_cb (GDBusConnection *connection, | |
| 212 | const gchar *name, | ||
| 213 | gpointer user_data) | ||
| 214 | { | ||
| 215 | ✗ | GssPeerManagerDBus *self = GSS_PEER_MANAGER_DBUS (user_data); | |
| 216 | |||
| 217 | ✗ | g_debug ("%s: Removing peer credentials for ‘%s’ from cache", G_STRFUNC, name); | |
| 218 | ✗ | if (g_hash_table_remove (self->peer_credentials, name)) | |
| 219 | { | ||
| 220 | /* Notify users of this API. */ | ||
| 221 | ✗ | g_signal_emit_by_name (self, "peer-vanished", name); | |
| 222 | } | ||
| 223 | ✗ | } | |
| 224 | |||
| 225 | /* An async function for getting credentials for D-Bus peers, either by querying | ||
| 226 | * the bus, or by getting them from a cache. */ | ||
| 227 | static void ensure_peer_credentials_cb (GObject *obj, | ||
| 228 | GAsyncResult *result, | ||
| 229 | gpointer user_data); | ||
| 230 | |||
| 231 | static void | ||
| 232 | ✗ | gss_peer_manager_dbus_ensure_peer_credentials_async (GssPeerManager *manager, | |
| 233 | const gchar *sender, | ||
| 234 | GCancellable *cancellable, | ||
| 235 | GAsyncReadyCallback callback, | ||
| 236 | gpointer user_data) | ||
| 237 | { | ||
| 238 | ✗ | GssPeerManagerDBus *self = GSS_PEER_MANAGER_DBUS (manager); | |
| 239 | |||
| 240 | ✗ | g_autoptr(GTask) task = g_task_new (self, cancellable, callback, user_data); | |
| 241 | ✗ | g_task_set_source_tag (task, (gpointer) gss_peer_manager_dbus_ensure_peer_credentials_async); | |
| 242 | ✗ | g_task_set_task_data (task, g_strdup (sender), g_free); | |
| 243 | |||
| 244 | /* Look up information about the sender so that we can (for example) | ||
| 245 | * prioritise downloads by sender. */ | ||
| 246 | ✗ | const gchar *peer_path = gss_peer_manager_get_peer_credentials (manager, sender); | |
| 247 | |||
| 248 | ✗ | if (peer_path != NULL) | |
| 249 | { | ||
| 250 | ✗ | g_debug ("%s: Found credentials in cache; path is ‘%s’", | |
| 251 | G_STRFUNC, peer_path); | ||
| 252 | ✗ | g_task_return_pointer (task, g_strdup (peer_path), g_free); | |
| 253 | } | ||
| 254 | else | ||
| 255 | { | ||
| 256 | /* Watch the peer so we can know if/when it disappears. */ | ||
| 257 | ✗ | guint watch_id = g_bus_watch_name_on_connection (self->connection, sender, | |
| 258 | G_BUS_NAME_WATCHER_FLAGS_NONE, | ||
| 259 | NULL, peer_vanished_cb, | ||
| 260 | self, NULL); | ||
| 261 | ✗ | g_ptr_array_add (self->peer_watch_ids, GUINT_TO_POINTER (watch_id)); | |
| 262 | |||
| 263 | /* And query for its credentials. */ | ||
| 264 | ✗ | g_dbus_connection_call (self->connection, "org.freedesktop.DBus", "/", | |
| 265 | "org.freedesktop.DBus", "GetConnectionCredentials", | ||
| 266 | g_variant_new ("(s)", sender), | ||
| 267 | G_VARIANT_TYPE ("(a{sv})"), | ||
| 268 | G_DBUS_CALL_FLAGS_NONE, | ||
| 269 | -1 /* default timeout */, | ||
| 270 | cancellable, | ||
| 271 | ensure_peer_credentials_cb, g_steal_pointer (&task)); | ||
| 272 | } | ||
| 273 | ✗ | } | |
| 274 | |||
| 275 | static void | ||
| 276 | ✗ | ensure_peer_credentials_cb (GObject *obj, | |
| 277 | GAsyncResult *result, | ||
| 278 | gpointer user_data) | ||
| 279 | { | ||
| 280 | ✗ | g_autoptr(GTask) task = G_TASK (user_data); | |
| 281 | ✗ | GssPeerManagerDBus *self = GSS_PEER_MANAGER_DBUS (g_task_get_source_object (task)); | |
| 282 | ✗ | GDBusConnection *connection = G_DBUS_CONNECTION (obj); | |
| 283 | ✗ | const gchar *sender = g_task_get_task_data (task); | |
| 284 | ✗ | g_autoptr(GError) local_error = NULL; | |
| 285 | |||
| 286 | /* Finish looking up the sender. */ | ||
| 287 | ✗ | g_autoptr(GVariant) retval = NULL; | |
| 288 | ✗ | retval = g_dbus_connection_call_finish (connection, result, &local_error); | |
| 289 | |||
| 290 | ✗ | if (retval == NULL) | |
| 291 | { | ||
| 292 | ✗ | g_task_return_error (task, g_steal_pointer (&local_error)); | |
| 293 | ✗ | return; | |
| 294 | } | ||
| 295 | |||
| 296 | /* From the credentials information from D-Bus, we can get the process ID, | ||
| 297 | * and then look up the process name. Note that this is racy (the process | ||
| 298 | * ID may get recycled between GetConnectionCredentials() returning and us | ||
| 299 | * querying the kernel for the process name), but there’s nothing we can | ||
| 300 | * do about that. The correct approach is to use an LSM label as returned | ||
| 301 | * by GetConnectionCredentials(), but EOS doesn’t support any LSM. | ||
| 302 | * We would look at /proc/$pid/exe, but that requires elevated privileges | ||
| 303 | * (CAP_SYS_PTRACE, but I can’t get that working; so it would require root | ||
| 304 | * privileges). Instead, we look at /proc/$pid/cmdline, which is accessible | ||
| 305 | * by all. Unfortunately, it is also forgeable. */ | ||
| 306 | guint process_id; | ||
| 307 | |||
| 308 | ✗ | g_autoptr(GVariant) credentials = g_variant_get_child_value (retval, 0); | |
| 309 | |||
| 310 | ✗ | if (!g_variant_lookup (credentials, "ProcessID", "u", &process_id)) | |
| 311 | { | ||
| 312 | ✗ | g_task_return_new_error (task, GSS_PEER_MANAGER_ERROR, | |
| 313 | GSS_PEER_MANAGER_ERROR_IDENTIFYING_PEER, | ||
| 314 | ✗ | _("Process ID for peer ‘%s’ could not be determined"), | |
| 315 | sender); | ||
| 316 | ✗ | return; | |
| 317 | } | ||
| 318 | |||
| 319 | ✗ | g_autofree gchar *pid_str = g_strdup_printf ("%u", process_id); | |
| 320 | ✗ | g_autofree gchar *proc_pid_cmdline = g_build_filename ("/proc", pid_str, "cmdline", NULL); | |
| 321 | ✗ | g_autofree gchar *cmdline = NULL; | |
| 322 | |||
| 323 | ✗ | g_debug ("%s: Getting contents of ‘%s’", G_STRFUNC, proc_pid_cmdline); | |
| 324 | |||
| 325 | /* Assume the path is always the first nul-terminated segment. */ | ||
| 326 | ✗ | if (!g_file_get_contents (proc_pid_cmdline, &cmdline, NULL, &local_error)) | |
| 327 | { | ||
| 328 | ✗ | g_task_return_new_error (task, GSS_PEER_MANAGER_ERROR, | |
| 329 | GSS_PEER_MANAGER_ERROR_IDENTIFYING_PEER, | ||
| 330 | ✗ | _("Executable path for peer ‘%s’ (process ID: %s) " | |
| 331 | "could not be determined: %s"), | ||
| 332 | ✗ | sender, pid_str, local_error->message); | |
| 333 | ✗ | return; | |
| 334 | } | ||
| 335 | |||
| 336 | /* Resolve to an absolute path, since what we get back might not be absolute. */ | ||
| 337 | ✗ | g_autofree gchar *sender_path = g_find_program_in_path (cmdline); | |
| 338 | |||
| 339 | ✗ | if (sender_path == NULL) | |
| 340 | { | ||
| 341 | ✗ | g_autofree gchar *message = | |
| 342 | ✗ | g_strdup_printf (_("Path ‘%s’ could not be resolved"), cmdline); | |
| 343 | ✗ | g_task_return_new_error (task, GSS_PEER_MANAGER_ERROR, | |
| 344 | GSS_PEER_MANAGER_ERROR_IDENTIFYING_PEER, | ||
| 345 | ✗ | _("Executable path for peer ‘%s’ (process ID: %s) " | |
| 346 | "could not be determined: %s"), | ||
| 347 | sender, pid_str, message); | ||
| 348 | ✗ | return; | |
| 349 | } | ||
| 350 | |||
| 351 | ✗ | g_debug ("%s: Got credentials from D-Bus daemon; path is ‘%s’ (resolved from ‘%s’)", | |
| 352 | G_STRFUNC, sender_path, cmdline); | ||
| 353 | |||
| 354 | ✗ | g_hash_table_replace (self->peer_credentials, | |
| 355 | ✗ | g_strdup (sender), g_strdup (sender_path)); | |
| 356 | |||
| 357 | ✗ | g_task_return_pointer (task, g_steal_pointer (&sender_path), g_free); | |
| 358 | } | ||
| 359 | |||
| 360 | static gchar * | ||
| 361 | ✗ | gss_peer_manager_dbus_ensure_peer_credentials_finish (GssPeerManager *manager, | |
| 362 | GAsyncResult *result, | ||
| 363 | GError **error) | ||
| 364 | { | ||
| 365 | ✗ | g_return_val_if_fail (g_task_is_valid (result, manager), NULL); | |
| 366 | ✗ | g_return_val_if_fail (g_async_result_is_tagged (result, (gpointer) gss_peer_manager_dbus_ensure_peer_credentials_async), NULL); | |
| 367 | |||
| 368 | ✗ | return g_task_propagate_pointer (G_TASK (result), error); | |
| 369 | } | ||
| 370 | |||
| 371 | static const gchar * | ||
| 372 | 1 | gss_peer_manager_dbus_get_peer_credentials (GssPeerManager *manager, | |
| 373 | const gchar *sender) | ||
| 374 | { | ||
| 375 | 1 | GssPeerManagerDBus *self = GSS_PEER_MANAGER_DBUS (manager); | |
| 376 | |||
| 377 | 1 | g_debug ("%s: Querying credentials for peer ‘%s’", G_STRFUNC, sender); | |
| 378 | 1 | return g_hash_table_lookup (self->peer_credentials, sender); | |
| 379 | } | ||
| 380 | |||
| 381 | /** | ||
| 382 | * gss_peer_manager_dbus_new: | ||
| 383 | * @connection: a #GDBusConnection | ||
| 384 | * | ||
| 385 | * Create a #GssPeerManagerDBus object to wrap the given existing @connection. | ||
| 386 | * | ||
| 387 | * Returns: (transfer full): a new #GssPeerManagerDBus wrapping @connection | ||
| 388 | * Since: 0.1.0 | ||
| 389 | */ | ||
| 390 | GssPeerManagerDBus * | ||
| 391 | 1 | gss_peer_manager_dbus_new (GDBusConnection *connection) | |
| 392 | { | ||
| 393 |
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1 | g_return_val_if_fail (G_IS_DBUS_CONNECTION (connection), NULL); |
| 394 | |||
| 395 | 1 | return g_object_new (GSS_TYPE_PEER_MANAGER_DBUS, | |
| 396 | "connection", connection, | ||
| 397 | NULL); | ||
| 398 | } | ||
| 399 |