From: Job Snijders <job@bsd.nl>
Subject: Re: ntpd timegm error checks
To: Theo Buehler <tb@theobuehler.org>
Cc: tech@openbsd.org
Date: Sun, 31 May 2026 10:59:43 +0000

OK

On Sun, May 31, 2026 at 12:23:26PM +0200, Theo Buehler wrote:
> Another rather straightforward conversion, removing a confusing comment
> that would become a bit more confusing.
> 
> As visible in the diff, tls_tm is parsed twice in a row, where the
> second (rather the first) parse was added with the manual constraints
> checking in 2019. The layering is a bit strange here.
> 
> Index: constraint.c
> ===================================================================
> RCS file: /cvs/src/usr.sbin/ntpd/constraint.c,v
> diff -u -p -r1.60 constraint.c
> --- constraint.c	21 Nov 2024 13:38:14 -0000	1.60
> +++ constraint.c	31 May 2026 10:14:09 -0000
> @@ -1062,7 +1062,9 @@ httpsdate_request(struct httpsdate *http
>  	 */
>  	notbefore = tls_peer_cert_notbefore(httpsdate->tls_ctx);
>  	notafter = tls_peer_cert_notafter(httpsdate->tls_ctx);
> -	if ((httptime = timegm(&httpsdate->tls_tm)) == -1)
> +	httpsdate->tls_tm.tm_wday = -1;
> +	if ((httptime = timegm(&httpsdate->tls_tm)) == -1 &&
> +	    httpsdate->tls_tm.tm_wday == -1)
>  		goto fail;
>  	if (httptime <= notbefore) {
>  		if ((tm = gmtime(&notbefore)) == NULL)
> @@ -1114,8 +1116,12 @@ httpsdate_query(const char *addr, const 
>  	if (httpsdate_request(httpsdate, &when, synced) == -1)
>  		return (NULL);
>  
> -	/* Return parsed date as local time */
> +	httpsdate->tls_tm.tm_wday = -1;
>  	t = timegm(&httpsdate->tls_tm);
> +	if (t == -1 && httpsdate->tls_tm.tm_wday == -1) {
> +		httpsdate_free(httpsdate);
> +		return (NULL);
> +	}
>  
>  	/* Report parsed Date: as "received time" */
>  	rectv->tv_sec = t;
>