This came up in the OpenNTPD issue tracker:
https://github.com/openntpd-portable/openntpd-openbsd/pull/4
The issue is an overflow when calculating time offsets with a 32-bit
time_t in early 2036. The main reason to fix it in now, in 2015, is that
OpenNTPD fails to adjust time if such a system simply has a bad initial
time value.
I could maintain this as a local patch on the portable tree, but it
felt like this one should be upstream rather than hidden away in a patch
file.
Suggestions on better wording or oks?
Maybe 'sorry in advance for prolonging the Android uprising an
additional 2 years'.
Index: client.c
===
RCS file: /cvs/src/usr.sbin/ntpd/client.c,v
retrieving revision 1.100
diff -u -p -u -p -r1.100 client.c
--- client.c12 Feb 2015 01:54:57 - 1.100
+++ client.c22 Mar 2015 03:21:08 -
@@ -258,7 +258,11 @@ client_dispatch(struct ntp_peer *p, u_in
if (cmsg-cmsg_level == SOL_SOCKET
cmsg-cmsg_type == SCM_TIMESTAMP) {
memcpy(tv, CMSG_DATA(cmsg), sizeof(tv));
- T4 += tv.tv_sec + JAN_1970 + 1.0e-6 * tv.tv_usec;
+ /*
+* Account for overflow that occurs on OSes that still
+* have a 32-bit time_t.
+*/
+ T4 += (uint64_t)tv.tv_sec + JAN_1970 + 1.0e-6 *
tv.tv_usec;
break;
}
}
Index: util.c
===
RCS file: /cvs/src/usr.sbin/ntpd/util.c,v
retrieving revision 1.18
diff -u -p -u -p -r1.18 util.c
--- util.c 10 Feb 2015 11:46:39 - 1.18
+++ util.c 22 Mar 2015 03:21:08 -
@@ -45,13 +45,21 @@ gettime(void)
if (gettimeofday(tv, NULL) == -1)
fatal(gettimeofday);
- return (tv.tv_sec + JAN_1970 + 1.0e-6 * tv.tv_usec);
+ /*
+* Account for overflow that occurs on OSes that still
+* have a 32-bit time_t.
+*/
+ return ((uint64_t)tv.tv_sec + JAN_1970 + 1.0e-6 * tv.tv_usec);
}
double
gettime_from_timeval(struct timeval *tv)
{
- return (tv-tv_sec + JAN_1970 + 1.0e-6 * tv-tv_usec);
+ /*
+* Account for overflow that occurs on OSes that still
+* have a 32-bit time_t.
+*/
+ return ((uint64_t)tv-tv_sec + JAN_1970 + 1.0e-6 * tv-tv_usec);
}
time_t
