Module Name: src
Committed By: riastradh
Date: Sun May 15 16:20:10 UTC 2022
Modified Files:
src/sys/kern: kern_time.c
Log Message:
adjtime(2): Handle negative tv_sec and tv_usec.
Previously I clamped these to avoid dangerous arithmetic overflow.
But I assumed sensible values should be nonnegative.
For tv_sec, this assumption was just wrong -- the adjustment may be
negative.
For tv_usec, this assumption is...not wrong, but also not right.
tv_usec is not _supposed_ to be negative (by POSIX, the type need
only represent values in [-1, 1000000]; semantically the member is
supposed to be a nonnegative number of microseconds below 1000000),
but ntp abuses it to hold negative values, for reasons unclear -- the
same effect could be had by subtracting one from tv_sec, and adding
1000000 to the negative tv_usec. However, let's not break existing
ntp userlands...
To generate a diff of this commit:
cvs rdiff -u -r1.213 -r1.214 src/sys/kern/kern_time.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/kern_time.c
diff -u src/sys/kern/kern_time.c:1.213 src/sys/kern/kern_time.c:1.214
--- src/sys/kern/kern_time.c:1.213 Sun Mar 13 12:21:28 2022
+++ src/sys/kern/kern_time.c Sun May 15 16:20:10 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_time.c,v 1.213 2022/03/13 12:21:28 riastradh Exp $ */
+/* $NetBSD: kern_time.c,v 1.214 2022/05/15 16:20:10 riastradh Exp $ */
/*-
* Copyright (c) 2000, 2004, 2005, 2007, 2008, 2009, 2020
@@ -62,7 +62,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_time.c,v 1.213 2022/03/13 12:21:28 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_time.c,v 1.214 2022/05/15 16:20:10 riastradh Exp $");
#include <sys/param.h>
#include <sys/resourcevar.h>
@@ -625,9 +625,11 @@ adjtime1(const struct timeval *delta, st
*/
if (delta->tv_sec > INT64_MAX/1000000 - 1) {
time_adjtime = INT64_MAX;
+ } else if (delta->tv_sec < INT64_MIN/1000000 + 1) {
+ time_adjtime = INT64_MIN;
} else {
- time_adjtime = MAX(0, delta->tv_sec) * 1000000
- + MAX(0, MIN(999999, delta->tv_usec));
+ time_adjtime = delta->tv_sec * 1000000
+ + MAX(-999999, MIN(999999, delta->tv_usec));
}
if (time_adjtime) {
