With TIME_BACKTRACK_PROTECTION defined, openvpn_gettimeofday() uses and
updates global variable "now_usec" along with "now" only if current time
is ahead of the previsouly stored, taking nanoseconds into account.
But, update_time() function updates only "now" leaving "now_usec" as
is with any previously value stored.
This breaks both update_time() and openvpn_gettimeofday() results and
leads to time jumps in the future within one second, can affect shaper
and user timers.
100.900 openvpn_gettimeofday():
now set to 100s, now_usec set to 100ns, stored time is 100.900
101.300 update_time():
now set to 101s, but now_usec is not updated and still 900ns, stored
time jumps to the future 101.900
101.600 openvpn_gettimeofday():
current time 101.600 is in the past relatively stored time 101.900,
now & now_usec variables are not updated, returned time 101.900 is
still and again incorrect
102.100 openvpn_gettimeofday():
current time 102.100 is no longer in the past relatively stored time
101.900, so now & now_usec get updated with wrong time delta from
previous openvpn_gettimeofday() call or now/now_usec math
Since update_time() and openvpn_gettimeofday() calls are mixed in runtime,
to fix their coexistance update_time() must update "now_usec" as well,
calling just update_now() is not enough.
Signed-off-by: Vladislav Grishenko <[email protected]>
---
src/openvpn/otime.h | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/src/openvpn/otime.h b/src/openvpn/otime.h
index a6f7ec25..fab4575c 100644
--- a/src/openvpn/otime.h
+++ b/src/openvpn/otime.h
@@ -78,13 +78,9 @@ openvpn_gettimeofday(struct timeval *tv, void *tz)
static inline void
update_time(void)
{
-#ifdef _WIN32
- /* on _WIN32, gettimeofday is faster than time(NULL) */
+ /* can't use time(NULL), now_usec needs to be updated */
struct timeval tv;
openvpn_gettimeofday(&tv, NULL);
-#else
- update_now(time(NULL));
-#endif
}
#else /* !TIME_BACKTRACK_PROTECTION */
--
2.17.1
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