The 32-bit integer part of the NTP timestamp overflows in year 2036, which starts the second NTP era.
Modify the timestamp conversion to shift values between 1900-1970 (in the first era) to the second era to enable the client to measure its offset correctly until year 2106 (assuming 64-bit time_t). Also update the conversion from double used when stepping the clock to work with 64-bit time_t after reaching the maximum 32-bit value in 2038 and the server conversion to work correctly in the next NTP era. Signed-off-by: Miroslav Lichvar <[email protected]> --- networking/ntpd.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/networking/ntpd.c b/networking/ntpd.c index 204e1d7c2..91faefcd8 100644 --- a/networking/ntpd.c +++ b/networking/ntpd.c @@ -554,7 +554,7 @@ gettime1900d(void) static void d_to_tv(struct timeval *tv, double d) { - tv->tv_sec = (long)d; + tv->tv_sec = (time_t)d; tv->tv_usec = (d - tv->tv_sec) * 1000000; } @@ -565,6 +565,9 @@ lfp_to_d(l_fixedpt_t lfp) lfp.int_partl = ntohl(lfp.int_partl); lfp.fractionl = ntohl(lfp.fractionl); ret = (double)lfp.int_partl + ((double)lfp.fractionl / UINT_MAX); + /* Shift timestamps before 1970 to the second NTP era (2036-2106) */ + if (lfp.int_partl < OFFSET_1900_1970) + ret += (double)UINT_MAX + 1.0; return ret; } static NOINLINE double @@ -582,8 +585,8 @@ d_to_lfp(l_fixedpt_t *lfp, double d) { uint32_t intl; uint32_t frac; - intl = (uint32_t)d; - frac = (uint32_t)((d - intl) * UINT_MAX); + intl = (uint32_t)(time_t)d; + frac = (uint32_t)((d - (time_t)d) * UINT_MAX); lfp->int_partl = htonl(intl); lfp->fractionl = htonl(frac); } -- 2.37.3 _______________________________________________ busybox mailing list [email protected] http://lists.busybox.net/mailman/listinfo/busybox
