/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */ /* dbus-server-socket.c Server implementation for sockets * * Copyright (C) 2002, 2003, 2004, 2006 Red Hat Inc. * * SPDX-License-Identifier: AFL-2.1 OR GPL-2.0-or-later * * Licensed under the Academic Free License version 2.1 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA * */ #include #include "dbus-internals.h" #include "dbus-server-socket.h" #include "dbus-transport-socket.h" #include "dbus-connection-internal.h" #include "dbus-memory.h" #include "dbus-nonce.h" #include "dbus-string.h" /** * @defgroup DBusServerSocket DBusServer implementations for SOCKET * @ingroup DBusInternals * @brief Implementation details of DBusServer on SOCKET * * @{ */ /** * * Opaque object representing a Socket server implementation. */ typedef struct DBusServerSocket DBusServerSocket; /** * Implementation details of DBusServerSocket. All members * are private. */ struct DBusServerSocket { DBusServer base; /**< Parent class members. */ int n_fds; /**< Number of active file handles */ DBusSocket *fds; /**< File descriptor or DBUS_SOCKET_INVALID if disconnected. */ DBusWatch **watch; /**< File descriptor watch. */ char *socket_name; /**< Name of domain socket, to unlink if appropriate */ DBusNonceFile *noncefile; /**< Nonce file used to authenticate clients */ }; static void socket_finalize (DBusServer *server) { DBusServerSocket *socket_server = (DBusServerSocket*) server; int i; _dbus_server_finalize_base (server); for (i = 0 ; i < socket_server->n_fds ; i++) if (socket_server->watch[i]) { _dbus_watch_unref (socket_server->watch[i]); socket_server->watch[i] = NULL; } dbus_free (socket_server->fds); dbus_free (socket_server->watch); dbus_free (socket_server->socket_name); _dbus_noncefile_delete (&socket_server->noncefile, NULL); dbus_free (server); } /* Return value is just for memory, not other failures. */ static dbus_bool_t handle_new_client_fd_and_unlock (DBusServer *server, DBusSocket client_fd) { DBusConnection *connection; DBusTransport *transport; DBusNewConnectionFunction new_connection_function; void *new_connection_data; _dbus_verbose ("Creating new client connection with fd %" DBUS_SOCKET_FORMAT "\n", _dbus_socket_printable (client_fd)); HAVE_LOCK_CHECK (server); if (!_dbus_set_socket_nonblocking (client_fd, NULL)) { SERVER_UNLOCK (server); return TRUE; } transport = _dbus_transport_new_for_socket (client_fd, &server->guid_hex, NULL); if (transport == NULL) { _dbus_close_socket (&client_fd, NULL); SERVER_UNLOCK (server); return FALSE; } if (!_dbus_transport_set_auth_mechanisms (transport, (const char **) server->auth_mechanisms)) { _dbus_transport_unref (transport); SERVER_UNLOCK (server); return FALSE; } /* note that client_fd is now owned by the transport, and will be * closed on transport disconnection/finalization */ connection = _dbus_connection_new_for_transport (transport); _dbus_transport_unref (transport); transport = NULL; /* now under the connection lock */ if (connection == NULL) { SERVER_UNLOCK (server); return FALSE; } /* See if someone wants to handle this new connection, self-referencing * for paranoia. */ new_connection_function = server->new_connection_function; new_connection_data = server->new_connection_data; _dbus_server_ref_unlocked (server); SERVER_UNLOCK (server); if (new_connection_function) { (* new_connection_function) (server, connection, new_connection_data); } dbus_server_unref (server); /* If no one grabbed a reference, the connection will die. */ _dbus_connection_close_if_only_one_ref (connection); dbus_connection_unref (connection); return TRUE; } static dbus_bool_t socket_handle_watch (DBusWatch *watch, unsigned int flags, void *data) { DBusServer *server = data; DBusServerSocket *socket_server = data; #ifndef DBUS_DISABLE_ASSERT int i; dbus_bool_t found = FALSE; #endif SERVER_LOCK (server); #ifndef DBUS_DISABLE_ASSERT for (i = 0 ; i < socket_server->n_fds ; i++) { if (socket_server->watch[i] == watch) { found = TRUE; break; } } _dbus_assert (found); #endif _dbus_verbose ("Handling client connection, flags 0x%x\n", flags); if (flags & DBUS_WATCH_READABLE) { DBusSocket client_fd; DBusSocket listen_fd; int saved_errno; listen_fd = _dbus_watch_get_socket (watch); if (socket_server->noncefile) client_fd = _dbus_accept_with_noncefile (listen_fd, socket_server->noncefile); else client_fd = _dbus_accept (listen_fd); saved_errno = _dbus_save_socket_errno (); if (!_dbus_socket_is_valid (client_fd)) { /* EINTR handled for us */ if (_dbus_get_is_errno_eagain_or_ewouldblock (saved_errno)) _dbus_verbose ("No client available to accept after all\n"); else _dbus_verbose ("Failed to accept a client connection: %s\n", _dbus_strerror (saved_errno)); SERVER_UNLOCK (server); } else { if (!handle_new_client_fd_and_unlock (server, client_fd)) _dbus_verbose ("Rejected client connection due to lack of memory\n"); } } if (flags & DBUS_WATCH_ERROR) _dbus_verbose ("Error on server listening socket\n"); if (flags & DBUS_WATCH_HANGUP) _dbus_verbose ("Hangup on server listening socket\n"); return TRUE; } static void socket_disconnect (DBusServer *server) { DBusServerSocket *socket_server = (DBusServerSocket*) server; int i; HAVE_LOCK_CHECK (server); for (i = 0 ; i < socket_server->n_fds ; i++) { if (socket_server->watch[i]) { _dbus_server_remove_watch (server, socket_server->watch[i]); _dbus_watch_invalidate (socket_server->watch[i]); _dbus_watch_unref (socket_server->watch[i]); socket_server->watch[i] = NULL; } if (_dbus_socket_is_valid (socket_server->fds[i])) _dbus_close_socket (&socket_server->fds[i], NULL); } if (socket_server->socket_name != NULL) { DBusString tmp; _dbus_string_init_const (&tmp, socket_server->socket_name); _dbus_delete_file (&tmp, NULL); } if (server->published_address) _dbus_daemon_unpublish_session_bus_address(); HAVE_LOCK_CHECK (server); } static const DBusServerVTable socket_vtable = { socket_finalize, socket_disconnect }; /** * Creates a new server listening on the given file descriptor. The * file descriptor should be nonblocking (use * _dbus_set_fd_nonblocking() to make it so). The file descriptor * should be listening for connections, that is, listen() should have * been successfully invoked on it. The server will use accept() to * accept new client connections. * * @param fds list of file descriptors. * @param n_fds number of file descriptors * @param address the server's address * @param noncefile to be used for authentication (NULL if not needed) * @param error location to store reason for failure * @returns the new server, or #NULL on OOM or other error. * */ DBusServer* _dbus_server_new_for_socket (DBusSocket *fds, int n_fds, const DBusString *address, DBusNonceFile *noncefile, DBusError *error) { DBusServerSocket *socket_server; DBusServer *server; int i; socket_server = dbus_new0 (DBusServerSocket, 1); if (socket_server == NULL) goto failed; socket_server->noncefile = noncefile; socket_server->fds = dbus_new (DBusSocket, n_fds); if (!socket_server->fds) goto failed; socket_server->watch = dbus_new0 (DBusWatch *, n_fds); if (!socket_server->watch) goto failed; for (i = 0 ; i < n_fds ; i++) { DBusWatch *watch; watch = _dbus_watch_new (_dbus_socket_get_pollable (fds[i]), DBUS_WATCH_READABLE, TRUE, socket_handle_watch, socket_server, NULL); if (watch == NULL) goto failed; socket_server->n_fds++; socket_server->fds[i] = fds[i]; socket_server->watch[i] = watch; } if (!_dbus_server_init_base (&socket_server->base, &socket_vtable, address, error)) goto failed; server = (DBusServer*)socket_server; SERVER_LOCK (server); for (i = 0 ; i < n_fds ; i++) { if (!_dbus_server_add_watch (&socket_server->base, socket_server->watch[i])) { int j; /* The caller is still responsible for closing the fds until * we return successfully, so don't let socket_disconnect() * close them */ for (j = 0; j < n_fds; j++) _dbus_socket_invalidate (&socket_server->fds[j]); /* socket_disconnect() will try to remove all the watches; * make sure it doesn't see the ones that weren't even added * yet */ for (j = i; j < n_fds; j++) { _dbus_watch_invalidate (socket_server->watch[j]); _dbus_watch_unref (socket_server->watch[j]); socket_server->watch[j] = NULL; } _dbus_server_disconnect_unlocked (server); SERVER_UNLOCK (server); _dbus_server_finalize_base (&socket_server->base); goto failed; } } SERVER_UNLOCK (server); _dbus_server_trace_ref (&socket_server->base, 0, 1, "new_for_socket"); return (DBusServer*) socket_server; failed: if (socket_server != NULL) { if (socket_server->watch != NULL) { for (i = 0; i < n_fds; i++) { if (socket_server->watch[i] != NULL) { _dbus_watch_invalidate (socket_server->watch[i]); _dbus_watch_unref (socket_server->watch[i]); socket_server->watch[i] = NULL; } } } dbus_free (socket_server->watch); dbus_free (socket_server->fds); dbus_free (socket_server); } if (error != NULL && !dbus_error_is_set (error)) _DBUS_SET_OOM (error); return NULL; } /** * Creates a new server listening on TCP. * If host is NULL, it will default to localhost. * If bind is NULL, it will default to the value for the host * parameter, and if that is NULL, then localhost * If bind is a hostname, it will be resolved and will listen * on all returned addresses. * If family is NULL, hostname resolution will try all address * families, otherwise it can be ipv4 or ipv6 to restrict the * addresses considered. * * @param host the hostname to report for the listen address * @param bind the hostname to listen on * @param port the port to listen on or 0 to let the OS choose * @param family * @param error location to store reason for failure. * @param use_nonce whether to use a nonce for low-level authentication (nonce-tcp transport) or not (tcp transport) * @returns the new server, or #NULL on failure. */ DBusServer* _dbus_server_new_for_tcp_socket (const char *host, const char *bind, const char *port, const char *family, DBusError *error, dbus_bool_t use_nonce) { DBusServer *server = NULL; DBusSocket *listen_fds = NULL; int nlisten_fds = 0, i; DBusString address = _DBUS_STRING_INIT_INVALID; DBusString host_str; /* Initialized as const later, not freed */ DBusString port_str = _DBUS_STRING_INIT_INVALID; DBusNonceFile *noncefile = NULL; const char *family_used = NULL; _DBUS_ASSERT_ERROR_IS_CLEAR (error); if (!_dbus_string_init (&address)) { dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL); goto failed; } if (!_dbus_string_init (&port_str)) { dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL); goto failed; } if (host == NULL) host = "localhost"; if (port == NULL) port = "0"; if (bind == NULL) bind = host; else if (strcmp (bind, "*") == 0) bind = NULL; nlisten_fds =_dbus_listen_tcp_socket (bind, port, family, &port_str, &family_used, &listen_fds, error); if (nlisten_fds <= 0) { _DBUS_ASSERT_ERROR_IS_SET(error); goto failed; } _dbus_string_init_const (&host_str, host); if (!_dbus_string_append (&address, use_nonce ? "nonce-tcp:host=" : "tcp:host=") || !_dbus_address_append_escaped (&address, &host_str) || !_dbus_string_append (&address, ",port=") || !_dbus_string_append (&address, _dbus_string_get_const_data(&port_str))) { dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL); goto failed; } if (family_used && (!_dbus_string_append (&address, ",family=") || !_dbus_string_append (&address, family_used))) { dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL); goto failed; } if (use_nonce) { if (!_dbus_noncefile_create (&noncefile, error)) goto failed; if (!_dbus_string_append (&address, ",noncefile=") || !_dbus_address_append_escaped (&address, _dbus_noncefile_get_path (noncefile))) { dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL); goto failed; } } server = _dbus_server_new_for_socket (listen_fds, nlisten_fds, &address, noncefile, error); if (server == NULL) goto failed; /* server has taken ownership of noncefile and the fds in listen_fds */ _dbus_string_free (&port_str); _dbus_string_free (&address); dbus_free(listen_fds); return server; failed: _dbus_noncefile_delete (&noncefile, NULL); if (listen_fds != NULL) { for (i = 0; i < nlisten_fds; i++) _dbus_close_socket (&listen_fds[i], NULL); dbus_free (listen_fds); } _dbus_string_free (&port_str); _dbus_string_free (&address); return NULL; } /** * Tries to interpret the address entry for various socket-related * addresses (well, currently only tcp and nonce-tcp). * * Sets error if the result is not OK. * * @param entry an address entry * @param server_p a new DBusServer, or #NULL on failure. * @param error location to store rationale for failure on bad address * @returns the outcome * */ DBusServerListenResult _dbus_server_listen_socket (DBusAddressEntry *entry, DBusServer **server_p, DBusError *error) { const char *method; *server_p = NULL; method = dbus_address_entry_get_method (entry); if (strcmp (method, "tcp") == 0 || strcmp (method, "nonce-tcp") == 0) { const char *host; const char *port; const char *bind; const char *family; host = dbus_address_entry_get_value (entry, "host"); bind = dbus_address_entry_get_value (entry, "bind"); port = dbus_address_entry_get_value (entry, "port"); family = dbus_address_entry_get_value (entry, "family"); *server_p = _dbus_server_new_for_tcp_socket (host, bind, port, family, error, strcmp (method, "nonce-tcp") == 0 ? TRUE : FALSE); if (*server_p) { _DBUS_ASSERT_ERROR_IS_CLEAR(error); return DBUS_SERVER_LISTEN_OK; } else { _DBUS_ASSERT_ERROR_IS_SET(error); return DBUS_SERVER_LISTEN_DID_NOT_CONNECT; } } else { _DBUS_ASSERT_ERROR_IS_CLEAR(error); return DBUS_SERVER_LISTEN_NOT_HANDLED; } } /** * This is a bad hack since it's really unix domain socket * specific. Also, the function weirdly adopts ownership * of the passed-in string. * * @param server a socket server * @param filename socket filename to report/delete * */ void _dbus_server_socket_own_filename (DBusServer *server, char *filename) { DBusServerSocket *socket_server = (DBusServerSocket*) server; socket_server->socket_name = filename; } /** * Creates a new server listening on the given Unix domain socket. * * @param path the path for the domain socket. * @param abstract #TRUE to use abstract socket namespace * @param error location to store reason for failure. * @returns the new server, or #NULL on failure. */ DBusServer* _dbus_server_new_for_domain_socket (const char *path, dbus_bool_t abstract, DBusError *error) { DBusServer *server; DBusSocket listen_fd; DBusString address; char *path_copy; DBusString path_str; _DBUS_ASSERT_ERROR_IS_CLEAR (error); if (!_dbus_string_init (&address)) { dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL); return NULL; } _dbus_string_init_const (&path_str, path); if ((abstract && !_dbus_string_append (&address, "unix:abstract=")) || (!abstract && !_dbus_string_append (&address, "unix:path=")) || !_dbus_address_append_escaped (&address, &path_str)) { dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL); goto failed_0; } if (abstract) { path_copy = NULL; } else { path_copy = _dbus_strdup (path); if (path_copy == NULL) { dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL); goto failed_0; } } listen_fd = _dbus_listen_unix_socket (path, abstract, error); if (!_dbus_socket_is_valid (listen_fd)) { _DBUS_ASSERT_ERROR_IS_SET (error); goto failed_1; } server = _dbus_server_new_for_socket (&listen_fd, 1, &address, 0, error); if (server == NULL) { goto failed_2; } if (path_copy != NULL) _dbus_server_socket_own_filename(server, path_copy); _dbus_string_free (&address); return server; failed_2: _dbus_close_socket (&listen_fd, NULL); failed_1: dbus_free (path_copy); failed_0: _dbus_string_free (&address); return NULL; } /** * Creates a new Unix domain socket server listening under the given directory. * This function is used for "unix:dir/tmpdir" kind of addresses. * * @param dir the path to a directory. * @param error location to store reason for failure. * @returns the new server, or #NULL on failure. */ static DBusServer * _dbus_server_new_for_dir (const char *dir, DBusError *error) { DBusServer *server; DBusString full_path; DBusString filename; if (!_dbus_string_init (&full_path)) { dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL); return NULL; } if (!_dbus_string_init (&filename)) { _dbus_string_free (&full_path); dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL); return NULL; } if (!_dbus_string_append (&filename, "dbus-")) { _dbus_string_free (&full_path); _dbus_string_free (&filename); dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL); return NULL; } if (!_dbus_generate_random_ascii (&filename, 10, error)) { _dbus_string_free (&full_path); _dbus_string_free (&filename); return NULL; } if (!_dbus_string_append (&full_path, dir) || !_dbus_concat_dir_and_file (&full_path, &filename)) { _dbus_string_free (&full_path); _dbus_string_free (&filename); dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL); return NULL; } server = _dbus_server_new_for_domain_socket (_dbus_string_get_const_data (&full_path), FALSE, /* not abstract */ error); _dbus_string_free (&full_path); _dbus_string_free (&filename); return server; } /** * Tries to interpret the address entry for UNIX socket * addresses. * * Sets error if the result is not OK. * * @param entry an address entry * @param server_p location to store a new DBusServer, or #NULL on failure. * @param error location to store rationale for failure on bad address * @returns the outcome * */ DBusServerListenResult _dbus_server_listen_unix_socket (DBusAddressEntry *entry, DBusServer **server_p, DBusError *error) { const char *method; *server_p = NULL; method = dbus_address_entry_get_method (entry); if (strcmp (method, "unix") == 0) { const char *path = dbus_address_entry_get_value (entry, "path"); const char *dir = dbus_address_entry_get_value (entry, "dir"); const char *tmpdir = dbus_address_entry_get_value (entry, "tmpdir"); const char *abstract = dbus_address_entry_get_value (entry, "abstract"); const char *runtime = dbus_address_entry_get_value (entry, "runtime"); int mutually_exclusive_modes = 0; mutually_exclusive_modes = (path != NULL) + (tmpdir != NULL) + (abstract != NULL) + (runtime != NULL) + (dir != NULL); if (mutually_exclusive_modes < 1) { _dbus_set_bad_address(error, "unix", "path or tmpdir or abstract or runtime or dir", NULL); return DBUS_SERVER_LISTEN_BAD_ADDRESS; } if (mutually_exclusive_modes > 1) { _dbus_set_bad_address(error, NULL, NULL, "cannot specify two of \"path\", \"tmpdir\", \"abstract\", \"runtime\" and \"dir\" at the same time"); return DBUS_SERVER_LISTEN_BAD_ADDRESS; } if (runtime != NULL) { DBusString full_path; DBusString filename; const char *runtimedir; if (strcmp (runtime, "yes") != 0) { _dbus_set_bad_address(error, NULL, NULL, "if given, the only value allowed for \"runtime\" is \"yes\""); return DBUS_SERVER_LISTEN_BAD_ADDRESS; } runtimedir = _dbus_getenv ("XDG_RUNTIME_DIR"); if (runtimedir == NULL) { dbus_set_error (error, DBUS_ERROR_NOT_SUPPORTED, "\"XDG_RUNTIME_DIR\" is not set"); return DBUS_SERVER_LISTEN_DID_NOT_CONNECT; } _dbus_string_init_const (&filename, "bus"); if (!_dbus_string_init (&full_path)) { _DBUS_SET_OOM (error); return DBUS_SERVER_LISTEN_DID_NOT_CONNECT; } if (!_dbus_string_append (&full_path, runtimedir) || !_dbus_concat_dir_and_file (&full_path, &filename)) { _dbus_string_free (&full_path); _DBUS_SET_OOM (error); return DBUS_SERVER_LISTEN_DID_NOT_CONNECT; } /* We can safely use filesystem sockets in the runtime directory, * and they are preferred because they can be bind-mounted between * Linux containers. */ *server_p = _dbus_server_new_for_domain_socket ( _dbus_string_get_const_data (&full_path), FALSE, error); _dbus_string_free (&full_path); } else if (tmpdir != NULL || dir != NULL) { /* tmpdir is now equivalent to dir. Previously it would try to * use an abstract socket. */ if (tmpdir != NULL) dir = tmpdir; *server_p = _dbus_server_new_for_dir (dir, error); } else { if (path) *server_p = _dbus_server_new_for_domain_socket (path, FALSE, error); else *server_p = _dbus_server_new_for_domain_socket (abstract, TRUE, error); } if (*server_p != NULL) { _DBUS_ASSERT_ERROR_IS_CLEAR(error); return DBUS_SERVER_LISTEN_OK; } else { _DBUS_ASSERT_ERROR_IS_SET(error); return DBUS_SERVER_LISTEN_DID_NOT_CONNECT; } } else { /* If we don't handle the method, we return NULL with the * error unset */ _DBUS_ASSERT_ERROR_IS_CLEAR(error); return DBUS_SERVER_LISTEN_NOT_HANDLED; } } /** @} */