Re: x11/xscreensaver 2026Q1 locks and no login

[Ramiro Aceves <ea1abz%gmail.com@localhost>]

On Mon, 5 Oct 2026 09:09:02 -0400
Jim Spath <jspath55%gmail.com@localhost> wrote:

> I took the liberty of sharing this issue, and [JdeBP] replied:
> 
> > The most likely causes were the calls to ctype functions in
> xft_word_wrap(), but those were changed to use unsigned char in 6.15. So if
> this really is 6.15 as claimed, the ctype negative character bug is no
> longer there to be hit, from a cursory inspection.
> 
> > The sensible first step would be to get a core dump.
> 
> Hope this helps.
> 
> Jim
> 
> 

Thanks, Jim. 

I have also written an email to the author but at me moment no reply.
If I issue this command today that is tuesday, a good working day
(with xscreensaver running on the background, as usual) :

/usr/pkg/libexec/xscreensaver/xscreensaver-auth

It shows a good working login screen

but on Saturdays it bombs out with a segfault. But, it does not leave a core dump. I tried to get a core dump but the executable is setuid root.

$ ls -lh /usr/pkg/libexec/xscreensaver/xscreensaver-auth
-r-s--x--x  1 root  wheel  645K Sep 30 10:59 /usr/pkg/libexec/xscreensaver/xscreensaver-auth

But if you execute is as root, it complains

netbsd-raspa4# /usr/pkg/libexec/xscreensaver/xscreensaver-auth
xscreensaver-auth: 08:32:00: running as user "root" -- authentication disallowed
netbsd-raspa4#

My lack of expertise... I cannot get a core dump that would clarify it.

Yes, it is 6.15 version:

netbsd-nuc$ pkgin se xscreensaver
xscreensaver-6.15nb2 = Screen saver and locker for the X window system

When compiling xscreensaver to include debugging symbols I see many warnings that perhaps correspond to this:

CTYPE(3)                   Library Functions Manual                   CTYPE(3)
..
..
     Because the bugs may manifest as silent misbehavior or as crashes only
     when fed input outside the US-ASCII range, the NetBSD implementation of
     the ctype functions is designed to elicit a compiler warning for code
     that passes inputs of type char in order to flag code that may pass
     negative values at runtime that would lead to undefined behavior
..
..

bsod.c:5357:17: warning: array subscript has type 'char' [-Wchar-subscripts]
 5357 |     if (isalpha(*s)) *s = toupper (*s);
      |                 ^
bsod.c:5357:36: warning: array subscript has type 'char' [-Wchar-subscripts]
 5357 |     if (isalpha(*s)) *s = toupper (*s);
      |                                    ^
bsod.c:5373:19: warning: array subscript has type 'char' [-Wchar-subscripts]
 5373 |       if (isalpha(*s)) *s = toupper (*s);
      |                   ^
bsod.c:5373:38: warning: array subscript has type 'char' [-Wchar-subscripts]
 5373 |       if (isalpha(*s)) *s = toupper (*s);


(this is an example of compiling xscreensaver un mi RPi4, just to show it)

Regards.
Ramiro.