dhcpd: fix an improper widening conversion

We wanted to detect when tv_sec = unsigned1 - unsigned2
underflows by looking at tv_sec's sign. But if tv_sec
is long and it is wider than unsigned, we get unsigned -> long
conversion which is in this case never negative.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2015-01-27 21:59:40 +01:00
parent 64b744997e
commit 936c401077

View File

@ -413,7 +413,8 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
max_sock = udhcp_sp_fd_set(&rfds, server_socket);
if (server_config.auto_time) {
tv.tv_sec = timeout_end - monotonic_sec();
/* cast to signed is essential if tv_sec is wider than int */
tv.tv_sec = (int)(timeout_end - monotonic_sec());
tv.tv_usec = 0;
}
retval = 0;