On Fri, Mar 04, 2016 at 11:32:51PM +0100, Christian Weisgerber wrote:
> Matthias Andree <mand...@freebsd.org> noticed that the constraint
> offset was always off by 3600 seconds for him (running OpenNTPD on
> FreeBSD with CET timezone).
>
> The way we parse the HTTP date in the ntpd constraint code isn't
> portable:
>
> if (strptime(p, "%a, %d %h %Y %T %Z",
> &httpsdate->tls_tm) == NULL) {
> ...
> /* Return parsed date as local time */
> t = timegm(&httpsdate->tls_tm);
>
> Neither %Z nor any kind of timezone information in struct tm are
> in POSIX. We end up with a time that, depending on the operating
> system, is off by the offset between local time and UTC.
>
> Since we only support the preferred HTTP date format from
> https://tools.ietf.org/html/rfc7231#section-7.1.1.1
> for which the timezone is fixed as the literal string "GMT",
> I suggest to simply replace %Z with GMT in the strptime() call.
>
> Comments? OK?
>
make sense, ok.
Cheers
Giovanni
>
> Index: constraint.c
> ===================================================================
> RCS file: /cvs/src/usr.sbin/ntpd/constraint.c,v
> retrieving revision 1.25
> diff -u -p -r1.25 constraint.c
> --- constraint.c 27 Jan 2016 21:48:34 -0000 1.25
> +++ constraint.c 4 Mar 2016 22:12:37 -0000
> @@ -903,7 +903,7 @@ httpsdate_request(struct httpsdate *http
> * or ANSI C's asctime() - the latter doesn't include
> * the timezone which is required here.
> */
> - if (strptime(p, "%a, %d %h %Y %T %Z",
> + if (strptime(p, "%a, %d %h %Y %T GMT",
> &httpsdate->tls_tm) == NULL) {
> log_warnx("unsupported date format");
> free(line);
>
> --
> Christian "naddy" Weisgerber na...@mips.inka.de
>
