From: David Zeuthen Date: Thu, 12 Apr 2012 03:05:33 +0000 (-0400) Subject: Avoid using monotonic time in the DBUS_COOKIE_SHA1 authentication method X-Git-Tag: dbus-1.6.0~7 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8734e4a16ff220a7af0fd718ba50f92d23c496cf;p=thirdparty%2Fdbus.git Avoid using monotonic time in the DBUS_COOKIE_SHA1 authentication method When libdbus-1 moved to using monotonic time support for the DBUS_COOKIE_SHA1 authentication was broken, in particular interoperability with non-libdbus-1 implementations such as GDBus. The problem is that if monotonic clocks are available in the OS, _dbus_get_current_time() will not return the number of seconds since the Epoch so using it for DBUS_COOKIE_SHA1 will violate the D-Bus specification. If both peers are using libdbus-1 it's not a problem since both ends will use the wrong time and thus agree. However, if the other end is another implementation and following the spec it will not work. First, we change _dbus_get_current_time() back so it always returns time since the Epoch and we then rename it _dbus_get_real_time() to make this clear. We then introduce _dbus_get_monotonic_time() and carefully make all current users of _dbus_get_current_time() use it, if applicable. During this audit, one of the callers, _dbus_generate_uuid(), was currently using monotonic time but it was decided to make it use real time instead. Signed-off-by: David Zeuthen Reviewed-by: Simon McVittie Bug: https://bugs.freedesktop.org/show_bug.cgi?id=48580 --- diff --git a/bus/connection.c b/bus/connection.c index 97e5f64b0..d69758c97 100644 --- a/bus/connection.c +++ b/bus/connection.c @@ -606,8 +606,8 @@ bus_connections_setup_connection (BusConnections *connections, d->connections = connections; d->connection = connection; - _dbus_get_current_time (&d->connection_tv_sec, - &d->connection_tv_usec); + _dbus_get_monotonic_time (&d->connection_tv_sec, + &d->connection_tv_usec); _dbus_assert (connection_data_slot >= 0); @@ -776,7 +776,7 @@ bus_connections_expire_incomplete (BusConnections *connections) DBusList *link; int auth_timeout; - _dbus_get_current_time (&tv_sec, &tv_usec); + _dbus_get_monotonic_time (&tv_sec, &tv_usec); auth_timeout = bus_context_get_auth_timeout (connections->context); link = _dbus_list_get_first_link (&connections->incomplete); @@ -1772,8 +1772,8 @@ bus_connections_expect_reply (BusConnections *connections, cprd->pending = pending; cprd->connections = connections; - _dbus_get_current_time (&pending->expire_item.added_tv_sec, - &pending->expire_item.added_tv_usec); + _dbus_get_monotonic_time (&pending->expire_item.added_tv_sec, + &pending->expire_item.added_tv_usec); _dbus_verbose ("Added pending reply %p, replier %p receiver %p serial %u\n", pending, diff --git a/bus/expirelist.c b/bus/expirelist.c index 3c87c1198..1a12ea456 100644 --- a/bus/expirelist.c +++ b/bus/expirelist.c @@ -123,9 +123,9 @@ bus_expire_list_recheck_immediately (BusExpireList *list) } static int -do_expiration_with_current_time (BusExpireList *list, - long tv_sec, - long tv_usec) +do_expiration_with_monotonic_time (BusExpireList *list, + long tv_sec, + long tv_usec) { DBusList *link; int next_interval, min_wait_time, items_to_expire; @@ -194,9 +194,9 @@ bus_expirelist_expire (BusExpireList *list) { long tv_sec, tv_usec; - _dbus_get_current_time (&tv_sec, &tv_usec); + _dbus_get_monotonic_time (&tv_sec, &tv_usec); - next_interval = do_expiration_with_current_time (list, tv_sec, tv_usec); + next_interval = do_expiration_with_monotonic_time (list, tv_sec, tv_usec); } bus_expire_timeout_set_interval (list->timeout, next_interval); @@ -340,7 +340,7 @@ bus_expire_list_test (const DBusString *test_data_dir) test_expire_func, NULL); _dbus_assert (list != NULL); - _dbus_get_current_time (&tv_sec, &tv_usec); + _dbus_get_monotonic_time (&tv_sec, &tv_usec); tv_sec_not_expired = tv_sec; tv_usec_not_expired = tv_usec; @@ -367,22 +367,22 @@ bus_expire_list_test (const DBusString *test_data_dir) _dbus_assert_not_reached ("out of memory"); next_interval = - do_expiration_with_current_time (list, tv_sec_not_expired, - tv_usec_not_expired); + do_expiration_with_monotonic_time (list, tv_sec_not_expired, + tv_usec_not_expired); _dbus_assert (item->expire_count == 0); _dbus_verbose ("next_interval = %d\n", next_interval); _dbus_assert (next_interval == 1); next_interval = - do_expiration_with_current_time (list, tv_sec_expired, - tv_usec_expired); + do_expiration_with_monotonic_time (list, tv_sec_expired, + tv_usec_expired); _dbus_assert (item->expire_count == 1); _dbus_verbose ("next_interval = %d\n", next_interval); _dbus_assert (next_interval == -1); next_interval = - do_expiration_with_current_time (list, tv_sec_past, - tv_usec_past); + do_expiration_with_monotonic_time (list, tv_sec_past, + tv_usec_past); _dbus_assert (item->expire_count == 1); _dbus_verbose ("next_interval = %d\n", next_interval); _dbus_assert (next_interval == 1000 + EXPIRE_AFTER); diff --git a/dbus/dbus-connection.c b/dbus/dbus-connection.c index ac0b2c0e7..ee33b6ccc 100644 --- a/dbus/dbus-connection.c +++ b/dbus/dbus-connection.c @@ -2388,7 +2388,7 @@ _dbus_connection_block_pending_call (DBusPendingCall *pending) * below */ timeout = _dbus_pending_call_get_timeout_unlocked (pending); - _dbus_get_current_time (&start_tv_sec, &start_tv_usec); + _dbus_get_monotonic_time (&start_tv_sec, &start_tv_usec); if (timeout) { timeout_milliseconds = dbus_timeout_get_interval (timeout); @@ -2445,7 +2445,7 @@ _dbus_connection_block_pending_call (DBusPendingCall *pending) return; } - _dbus_get_current_time (&tv_sec, &tv_usec); + _dbus_get_monotonic_time (&tv_sec, &tv_usec); elapsed_milliseconds = (tv_sec - start_tv_sec) * 1000 + (tv_usec - start_tv_usec) / 1000; diff --git a/dbus/dbus-internals.c b/dbus/dbus-internals.c index a5db14604..0e5d807e7 100644 --- a/dbus/dbus-internals.c +++ b/dbus/dbus-internals.c @@ -660,7 +660,10 @@ _dbus_generate_uuid (DBusGUID *uuid) { long now; - _dbus_get_current_time (&now, NULL); + /* don't use monotonic time because the UUID may be saved to disk, e.g. + * it may persist across reboots + */ + _dbus_get_real_time (&now, NULL); uuid->as_uint32s[DBUS_UUID_LENGTH_WORDS - 1] = DBUS_UINT32_TO_BE (now); diff --git a/dbus/dbus-keyring.c b/dbus/dbus-keyring.c index 35e8d74e0..23b9df5a0 100644 --- a/dbus/dbus-keyring.c +++ b/dbus/dbus-keyring.c @@ -353,7 +353,7 @@ add_new_key (DBusKey **keys_p, goto out; } - _dbus_get_current_time (×tamp, NULL); + _dbus_get_real_time (×tamp, NULL); keys[n_keys-1].id = id; keys[n_keys-1].creation_time = timestamp; @@ -428,7 +428,7 @@ _dbus_keyring_reload (DBusKeyring *keyring, retval = FALSE; have_lock = FALSE; - _dbus_get_current_time (&now, NULL); + _dbus_get_real_time (&now, NULL); if (add_new) { @@ -908,7 +908,7 @@ find_recent_key (DBusKeyring *keyring) int i; long tv_sec, tv_usec; - _dbus_get_current_time (&tv_sec, &tv_usec); + _dbus_get_real_time (&tv_sec, &tv_usec); i = 0; while (i < keyring->n_keys) diff --git a/dbus/dbus-mainloop.c b/dbus/dbus-mainloop.c index 8a30f7fe0..cef676a3a 100644 --- a/dbus/dbus-mainloop.c +++ b/dbus/dbus-mainloop.c @@ -91,8 +91,8 @@ timeout_callback_new (DBusTimeout *timeout) return NULL; cb->timeout = timeout; - _dbus_get_current_time (&cb->last_tv_sec, - &cb->last_tv_usec); + _dbus_get_monotonic_time (&cb->last_tv_sec, + &cb->last_tv_usec); return cb; } @@ -619,7 +619,7 @@ _dbus_loop_iterate (DBusLoop *loop, unsigned long tv_sec; unsigned long tv_usec; - _dbus_get_current_time (&tv_sec, &tv_usec); + _dbus_get_monotonic_time (&tv_sec, &tv_usec); link = _dbus_list_get_first_link (&loop->timeouts); while (link != NULL) @@ -728,7 +728,7 @@ _dbus_loop_iterate (DBusLoop *loop, unsigned long tv_sec; unsigned long tv_usec; - _dbus_get_current_time (&tv_sec, &tv_usec); + _dbus_get_monotonic_time (&tv_sec, &tv_usec); /* It'd be nice to avoid this O(n) thingy here */ link = _dbus_list_get_first_link (&loop->timeouts); diff --git a/dbus/dbus-sysdeps-unix.c b/dbus/dbus-sysdeps-unix.c index 9fddca73d..cef8bd310 100644 --- a/dbus/dbus-sysdeps-unix.c +++ b/dbus/dbus-sysdeps-unix.c @@ -2598,11 +2598,11 @@ _dbus_poll (DBusPollFD *fds, * available, to avoid problems when the system time changes. * * @param tv_sec return location for number of seconds - * @param tv_usec return location for number of microseconds (thousandths) + * @param tv_usec return location for number of microseconds */ void -_dbus_get_current_time (long *tv_sec, - long *tv_usec) +_dbus_get_monotonic_time (long *tv_sec, + long *tv_usec) { #ifdef HAVE_MONOTONIC_CLOCK struct timespec ts; @@ -2624,6 +2624,27 @@ _dbus_get_current_time (long *tv_sec, #endif } +/** + * Get current time, as in gettimeofday(). Never uses the monotonic + * clock. + * + * @param tv_sec return location for number of seconds + * @param tv_usec return location for number of microseconds + */ +void +_dbus_get_real_time (long *tv_sec, + long *tv_usec) +{ + struct timeval t; + + gettimeofday (&t, NULL); + + if (tv_sec) + *tv_sec = t.tv_sec; + if (tv_usec) + *tv_usec = t.tv_usec; +} + /** * Creates a directory; succeeds if the directory * is created or already existed. diff --git a/dbus/dbus-sysdeps-win.c b/dbus/dbus-sysdeps-win.c index e30e92fe7..397520af7 100644 --- a/dbus/dbus-sysdeps-win.c +++ b/dbus/dbus-sysdeps-win.c @@ -1872,14 +1872,15 @@ _dbus_sleep_milliseconds (int milliseconds) /** - * Get current time, as in gettimeofday(). + * Get current time, as in gettimeofday(). Never uses the monotonic + * clock. * * @param tv_sec return location for number of seconds * @param tv_usec return location for number of microseconds */ void -_dbus_get_current_time (long *tv_sec, - long *tv_usec) +_dbus_get_real_time (long *tv_sec, + long *tv_usec) { FILETIME ft; dbus_uint64_t time64; @@ -1901,6 +1902,20 @@ _dbus_get_current_time (long *tv_sec, *tv_usec = time64 % 1000000; } +/** + * Get current time, as in gettimeofday(). Use the monotonic clock if + * available, to avoid problems when the system time changes. + * + * @param tv_sec return location for number of seconds + * @param tv_usec return location for number of microseconds + */ +void +_dbus_get_monotonic_time (long *tv_sec, + long *tv_usec) +{ + /* no implementation yet, fall back to wall-clock time */ + _dbus_get_real_time (tv_sec, tv_usec); +} /** * signal (SIGPIPE, SIG_IGN); diff --git a/dbus/dbus-sysdeps.c b/dbus/dbus-sysdeps.c index 1a93cea79..861bfec9e 100644 --- a/dbus/dbus-sysdeps.c +++ b/dbus/dbus-sysdeps.c @@ -508,7 +508,7 @@ _dbus_generate_pseudorandom_bytes_buffer (char *buffer, _dbus_verbose ("Falling back to pseudorandom for %d bytes\n", n_bytes); - _dbus_get_current_time (NULL, &tv_usec); + _dbus_get_real_time (NULL, &tv_usec); srand (tv_usec); i = 0; diff --git a/dbus/dbus-sysdeps.h b/dbus/dbus-sysdeps.h index f8438f435..c03e2f54b 100644 --- a/dbus/dbus-sysdeps.h +++ b/dbus/dbus-sysdeps.h @@ -308,8 +308,11 @@ int _dbus_poll (DBusPollFD *fds, void _dbus_sleep_milliseconds (int milliseconds); -void _dbus_get_current_time (long *tv_sec, - long *tv_usec); +void _dbus_get_real_time (long *tv_sec, + long *tv_usec); + +void _dbus_get_monotonic_time (long *tv_sec, + long *tv_usec); /** * directory interface diff --git a/test/break-loader.c b/test/break-loader.c index 542f36ffd..e62b8c207 100644 --- a/test/break-loader.c +++ b/test/break-loader.c @@ -667,7 +667,7 @@ get_random_seed (void) fprintf (stderr, "could not open/read /dev/urandom, using current time for seed\n"); - _dbus_get_current_time (NULL, &tv_usec); + _dbus_get_monotonic_time (NULL, &tv_usec); seed = tv_usec; } diff --git a/test/name-test/test-pending-call-dispatch.c b/test/name-test/test-pending-call-dispatch.c index 57582d490..c8b5a4678 100644 --- a/test/name-test/test-pending-call-dispatch.c +++ b/test/name-test/test-pending-call-dispatch.c @@ -98,9 +98,9 @@ main (int argc, char *argv[]) { long delta; - _dbus_get_current_time (&start_tv_sec, &start_tv_usec); + _dbus_get_monotonic_time (&start_tv_sec, &start_tv_usec); _run_iteration (conn); - _dbus_get_current_time (&end_tv_sec, &end_tv_usec); + _dbus_get_monotonic_time (&end_tv_sec, &end_tv_usec); /* we just care about seconds */ delta = end_tv_sec - start_tv_sec; diff --git a/test/name-test/test-pending-call-timeout.c b/test/name-test/test-pending-call-timeout.c index 381113bd2..d051faba9 100644 --- a/test/name-test/test-pending-call-timeout.c +++ b/test/name-test/test-pending-call-timeout.c @@ -82,9 +82,9 @@ main (int argc, char *argv[]) { long delta; - _dbus_get_current_time (&start_tv_sec, &start_tv_usec); + _dbus_get_monotonic_time (&start_tv_sec, &start_tv_usec); _run_iteration (conn); - _dbus_get_current_time (&end_tv_sec, &end_tv_usec); + _dbus_get_monotonic_time (&end_tv_sec, &end_tv_usec); /* we just care about seconds */ delta = end_tv_sec - start_tv_sec;