dbus: Deal with undefined behavior with va_args.

Parse out a copy of the varargs ourselves to get to the reply portion, since
the original passed to D-Bus might modify or not modify the caller's copy,
depending on system ABI.
This commit is contained in:
Ryan C. Gordon 2018-07-13 17:53:24 -04:00
parent fd8e8f9f20
commit b5a420cb11
1 changed files with 15 additions and 3 deletions

View File

@ -173,17 +173,29 @@ SDL_DBus_CallMethodInternal(DBusConnection *conn, const char *node, const char *
if (conn) {
DBusMessage *msg = dbus.message_new_method_call(node, path, interface, method);
if (msg) {
int firstarg = va_arg(ap, int);
int firstarg;
va_list ap_reply;
va_copy(ap_reply, ap); /* copy the arg list so we don't compete with D-Bus for it */
firstarg = va_arg(ap, int);
if ((firstarg == DBUS_TYPE_INVALID) || dbus.message_append_args_valist(msg, firstarg, ap)) {
DBusMessage *reply = dbus.connection_send_with_reply_and_block(conn, msg, 300, NULL);
if (reply) {
firstarg = va_arg(ap, int);
if ((firstarg == DBUS_TYPE_INVALID) || dbus.message_get_args_valist(reply, NULL, firstarg, ap)) {
/* skip any input args, get to output args. */
while ((firstarg = va_arg(ap_reply, int)) != DBUS_TYPE_INVALID) {
/* we assume D-Bus already validated all this. */
{ void *dumpptr = va_arg(ap_reply, void*); (void) dumpptr; }
if (firstarg == DBUS_TYPE_ARRAY) {
{ const int dumpint = va_arg(ap_reply, int); (void) dumpint; }
}
}
firstarg = va_arg(ap_reply, int);
if ((firstarg == DBUS_TYPE_INVALID) || dbus.message_get_args_valist(reply, NULL, firstarg, ap_reply)) {
retval = SDL_TRUE;
}
dbus.message_unref(reply);
}
}
va_end(ap_reply);
dbus.message_unref(msg);
}
}