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- From 0155adc8a0e61c0b1b7dc8febcba049b0d84bb31 Mon Sep 17 00:00:00 2001
- From: Brent Cook <busterb@gmail.com>
- Date: Sun, 22 Mar 2015 16:18:20 -0500
- Subject: [PATCH 11/11] Account for integer overflows with a 32-bit time_t
-
- If the current time is set past Feb. 2036, adding the NTP epoch offset
- overflows the time_t. While all systems in 2036 should have been running
- with a larger time_t for some time, today an invalid system clock cannot
- be reset with the overflow.
-
- Thanks to @Romua1d on github for point it out.
- ---
- src/usr.sbin/ntpd/client.c | 6 +++++-
- src/usr.sbin/ntpd/util.c | 12 ++++++++++--
- 2 files changed, 15 insertions(+), 3 deletions(-)
-
- diff --git a/src/usr.sbin/ntpd/client.c b/src/usr.sbin/ntpd/client.c
- index d47869b..70879c0 100644
- --- a/src/usr.sbin/ntpd/client.c
- +++ b/src/usr.sbin/ntpd/client.c
- @@ -269,7 +269,11 @@ client_dispatch(struct ntp_peer *p, u_int8_t settime)
- 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;
- }
- }
- diff --git a/src/usr.sbin/ntpd/util.c b/src/usr.sbin/ntpd/util.c
- index 0867ed7..e9f6d50 100644
- --- a/src/usr.sbin/ntpd/util.c
- +++ b/src/usr.sbin/ntpd/util.c
- @@ -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
- --
- 1.9.1
-
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