diff options
Diffstat (limited to 'drivers/tty/tty_io.c')
| -rw-r--r-- | drivers/tty/tty_io.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 3949d95..e569546 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1025,11 +1025,17 @@ void start_tty(struct tty_struct *tty) } EXPORT_SYMBOL(start_tty); -/* We limit tty time update visibility to every 8 seconds or so. */ static void tty_update_time(struct timespec *time) { unsigned long sec = get_seconds(); - if (abs(sec - time->tv_sec) & ~7) + + /* + * We only care if the two values differ in anything other than the + * lower three bits (i.e every 8 seconds). If so, then we can update + * the time of the tty device, otherwise it could be construded as a + * security leak to let userspace know the exact timing of the tty. + */ + if ((sec ^ time->tv_sec) & ~7) time->tv_sec = sec; } |